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Diffstat (limited to '')
27 files changed, 11864 insertions, 0 deletions
diff --git a/security/keys/Kconfig b/security/keys/Kconfig new file mode 100644 index 000000000..6462e6654 --- /dev/null +++ b/security/keys/Kconfig @@ -0,0 +1,103 @@ +# +# Key management configuration +# + +config KEYS + bool "Enable access key retention support" + select ASSOCIATIVE_ARRAY + help + This option provides support for retaining authentication tokens and + access keys in the kernel. + + It also includes provision of methods by which such keys might be + associated with a process so that network filesystems, encryption + support and the like can find them. + + Furthermore, a special type of key is available that acts as keyring: + a searchable sequence of keys. Each process is equipped with access + to five standard keyrings: UID-specific, GID-specific, session, + process and thread. + + If you are unsure as to whether this is required, answer N. + +config KEYS_COMPAT + def_bool y + depends on COMPAT && KEYS + +config PERSISTENT_KEYRINGS + bool "Enable register of persistent per-UID keyrings" + depends on KEYS + help + This option provides a register of persistent per-UID keyrings, + primarily aimed at Kerberos key storage. The keyrings are persistent + in the sense that they stay around after all processes of that UID + have exited, not that they survive the machine being rebooted. + + A particular keyring may be accessed by either the user whose keyring + it is or by a process with administrative privileges. The active + LSMs gets to rule on which admin-level processes get to access the + cache. + + Keyrings are created and added into the register upon demand and get + removed if they expire (a default timeout is set upon creation). + +config BIG_KEYS + bool "Large payload keys" + depends on KEYS + depends on TMPFS + select CRYPTO + select CRYPTO_AES + select CRYPTO_GCM + help + This option provides support for holding large keys within the kernel + (for example Kerberos ticket caches). The data may be stored out to + swapspace by tmpfs. + + If you are unsure as to whether this is required, answer N. + +config TRUSTED_KEYS + tristate "TRUSTED KEYS" + depends on KEYS && TCG_TPM + select CRYPTO + select CRYPTO_HMAC + select CRYPTO_SHA1 + select CRYPTO_HASH_INFO + help + This option provides support for creating, sealing, and unsealing + keys in the kernel. Trusted keys are random number symmetric keys, + generated and RSA-sealed by the TPM. The TPM only unseals the keys, + if the boot PCRs and other criteria match. Userspace will only ever + see encrypted blobs. + + If you are unsure as to whether this is required, answer N. + +config ENCRYPTED_KEYS + tristate "ENCRYPTED KEYS" + depends on KEYS + select CRYPTO + select CRYPTO_HMAC + select CRYPTO_AES + select CRYPTO_CBC + select CRYPTO_SHA256 + select CRYPTO_RNG + help + This option provides support for create/encrypting/decrypting keys + in the kernel. Encrypted keys are kernel generated random numbers, + which are encrypted/decrypted with a 'master' symmetric key. The + 'master' key can be either a trusted-key or user-key type. + Userspace only ever sees/stores encrypted blobs. + + If you are unsure as to whether this is required, answer N. + +config KEY_DH_OPERATIONS + bool "Diffie-Hellman operations on retained keys" + depends on KEYS + select CRYPTO + select CRYPTO_HASH + select CRYPTO_DH + help + This option provides support for calculating Diffie-Hellman + public keys and shared secrets using values stored as keys + in the kernel. + + If you are unsure as to whether this is required, answer N. diff --git a/security/keys/Makefile b/security/keys/Makefile new file mode 100644 index 000000000..ef1581b33 --- /dev/null +++ b/security/keys/Makefile @@ -0,0 +1,31 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for key management +# + +# +# Core +# +obj-y := \ + gc.o \ + key.o \ + keyring.o \ + keyctl.o \ + permission.o \ + process_keys.o \ + request_key.o \ + request_key_auth.o \ + user_defined.o +compat-obj-$(CONFIG_KEY_DH_OPERATIONS) += compat_dh.o +obj-$(CONFIG_KEYS_COMPAT) += compat.o $(compat-obj-y) +obj-$(CONFIG_PROC_FS) += proc.o +obj-$(CONFIG_SYSCTL) += sysctl.o +obj-$(CONFIG_PERSISTENT_KEYRINGS) += persistent.o +obj-$(CONFIG_KEY_DH_OPERATIONS) += dh.o + +# +# Key types +# +obj-$(CONFIG_BIG_KEYS) += big_key.o +obj-$(CONFIG_TRUSTED_KEYS) += trusted.o +obj-$(CONFIG_ENCRYPTED_KEYS) += encrypted-keys/ diff --git a/security/keys/big_key.c b/security/keys/big_key.c new file mode 100644 index 000000000..630594a5b --- /dev/null +++ b/security/keys/big_key.c @@ -0,0 +1,453 @@ +/* Large capacity key type + * + * Copyright (C) 2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "big_key: "fmt +#include <linux/init.h> +#include <linux/seq_file.h> +#include <linux/file.h> +#include <linux/shmem_fs.h> +#include <linux/err.h> +#include <linux/scatterlist.h> +#include <linux/random.h> +#include <linux/vmalloc.h> +#include <keys/user-type.h> +#include <keys/big_key-type.h> +#include <crypto/aead.h> +#include <crypto/gcm.h> + +struct big_key_buf { + unsigned int nr_pages; + void *virt; + struct scatterlist *sg; + struct page *pages[]; +}; + +/* + * Layout of key payload words. + */ +enum { + big_key_data, + big_key_path, + big_key_path_2nd_part, + big_key_len, +}; + +/* + * Crypto operation with big_key data + */ +enum big_key_op { + BIG_KEY_ENC, + BIG_KEY_DEC, +}; + +/* + * If the data is under this limit, there's no point creating a shm file to + * hold it as the permanently resident metadata for the shmem fs will be at + * least as large as the data. + */ +#define BIG_KEY_FILE_THRESHOLD (sizeof(struct inode) + sizeof(struct dentry)) + +/* + * Key size for big_key data encryption + */ +#define ENC_KEY_SIZE 32 + +/* + * Authentication tag length + */ +#define ENC_AUTHTAG_SIZE 16 + +/* + * big_key defined keys take an arbitrary string as the description and an + * arbitrary blob of data as the payload + */ +struct key_type key_type_big_key = { + .name = "big_key", + .preparse = big_key_preparse, + .free_preparse = big_key_free_preparse, + .instantiate = generic_key_instantiate, + .revoke = big_key_revoke, + .destroy = big_key_destroy, + .describe = big_key_describe, + .read = big_key_read, + /* no ->update(); don't add it without changing big_key_crypt() nonce */ +}; + +/* + * Crypto names for big_key data authenticated encryption + */ +static const char big_key_alg_name[] = "gcm(aes)"; +#define BIG_KEY_IV_SIZE GCM_AES_IV_SIZE + +/* + * Crypto algorithms for big_key data authenticated encryption + */ +static struct crypto_aead *big_key_aead; + +/* + * Since changing the key affects the entire object, we need a mutex. + */ +static DEFINE_MUTEX(big_key_aead_lock); + +/* + * Encrypt/decrypt big_key data + */ +static int big_key_crypt(enum big_key_op op, struct big_key_buf *buf, size_t datalen, u8 *key) +{ + int ret; + struct aead_request *aead_req; + /* We always use a zero nonce. The reason we can get away with this is + * because we're using a different randomly generated key for every + * different encryption. Notably, too, key_type_big_key doesn't define + * an .update function, so there's no chance we'll wind up reusing the + * key to encrypt updated data. Simply put: one key, one encryption. + */ + u8 zero_nonce[BIG_KEY_IV_SIZE]; + + aead_req = aead_request_alloc(big_key_aead, GFP_KERNEL); + if (!aead_req) + return -ENOMEM; + + memset(zero_nonce, 0, sizeof(zero_nonce)); + aead_request_set_crypt(aead_req, buf->sg, buf->sg, datalen, zero_nonce); + aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); + aead_request_set_ad(aead_req, 0); + + mutex_lock(&big_key_aead_lock); + if (crypto_aead_setkey(big_key_aead, key, ENC_KEY_SIZE)) { + ret = -EAGAIN; + goto error; + } + if (op == BIG_KEY_ENC) + ret = crypto_aead_encrypt(aead_req); + else + ret = crypto_aead_decrypt(aead_req); +error: + mutex_unlock(&big_key_aead_lock); + aead_request_free(aead_req); + return ret; +} + +/* + * Free up the buffer. + */ +static void big_key_free_buffer(struct big_key_buf *buf) +{ + unsigned int i; + + if (buf->virt) { + memset(buf->virt, 0, buf->nr_pages * PAGE_SIZE); + vunmap(buf->virt); + } + + for (i = 0; i < buf->nr_pages; i++) + if (buf->pages[i]) + __free_page(buf->pages[i]); + + kfree(buf); +} + +/* + * Allocate a buffer consisting of a set of pages with a virtual mapping + * applied over them. + */ +static void *big_key_alloc_buffer(size_t len) +{ + struct big_key_buf *buf; + unsigned int npg = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; + unsigned int i, l; + + buf = kzalloc(sizeof(struct big_key_buf) + + sizeof(struct page) * npg + + sizeof(struct scatterlist) * npg, + GFP_KERNEL); + if (!buf) + return NULL; + + buf->nr_pages = npg; + buf->sg = (void *)(buf->pages + npg); + sg_init_table(buf->sg, npg); + + for (i = 0; i < buf->nr_pages; i++) { + buf->pages[i] = alloc_page(GFP_KERNEL); + if (!buf->pages[i]) + goto nomem; + + l = min_t(size_t, len, PAGE_SIZE); + sg_set_page(&buf->sg[i], buf->pages[i], l, 0); + len -= l; + } + + buf->virt = vmap(buf->pages, buf->nr_pages, VM_MAP, PAGE_KERNEL); + if (!buf->virt) + goto nomem; + + return buf; + +nomem: + big_key_free_buffer(buf); + return NULL; +} + +/* + * Preparse a big key + */ +int big_key_preparse(struct key_preparsed_payload *prep) +{ + struct big_key_buf *buf; + struct path *path = (struct path *)&prep->payload.data[big_key_path]; + struct file *file; + u8 *enckey; + ssize_t written; + size_t datalen = prep->datalen, enclen = datalen + ENC_AUTHTAG_SIZE; + int ret; + + if (datalen <= 0 || datalen > 1024 * 1024 || !prep->data) + return -EINVAL; + + /* Set an arbitrary quota */ + prep->quotalen = 16; + + prep->payload.data[big_key_len] = (void *)(unsigned long)datalen; + + if (datalen > BIG_KEY_FILE_THRESHOLD) { + /* Create a shmem file to store the data in. This will permit the data + * to be swapped out if needed. + * + * File content is stored encrypted with randomly generated key. + */ + loff_t pos = 0; + + buf = big_key_alloc_buffer(enclen); + if (!buf) + return -ENOMEM; + memcpy(buf->virt, prep->data, datalen); + + /* generate random key */ + enckey = kmalloc(ENC_KEY_SIZE, GFP_KERNEL); + if (!enckey) { + ret = -ENOMEM; + goto error; + } + ret = get_random_bytes_wait(enckey, ENC_KEY_SIZE); + if (unlikely(ret)) + goto err_enckey; + + /* encrypt aligned data */ + ret = big_key_crypt(BIG_KEY_ENC, buf, datalen, enckey); + if (ret) + goto err_enckey; + + /* save aligned data to file */ + file = shmem_kernel_file_setup("", enclen, 0); + if (IS_ERR(file)) { + ret = PTR_ERR(file); + goto err_enckey; + } + + written = kernel_write(file, buf->virt, enclen, &pos); + if (written != enclen) { + ret = written; + if (written >= 0) + ret = -ENOMEM; + goto err_fput; + } + + /* Pin the mount and dentry to the key so that we can open it again + * later + */ + prep->payload.data[big_key_data] = enckey; + *path = file->f_path; + path_get(path); + fput(file); + big_key_free_buffer(buf); + } else { + /* Just store the data in a buffer */ + void *data = kmalloc(datalen, GFP_KERNEL); + + if (!data) + return -ENOMEM; + + prep->payload.data[big_key_data] = data; + memcpy(data, prep->data, prep->datalen); + } + return 0; + +err_fput: + fput(file); +err_enckey: + kzfree(enckey); +error: + big_key_free_buffer(buf); + return ret; +} + +/* + * Clear preparsement. + */ +void big_key_free_preparse(struct key_preparsed_payload *prep) +{ + if (prep->datalen > BIG_KEY_FILE_THRESHOLD) { + struct path *path = (struct path *)&prep->payload.data[big_key_path]; + + path_put(path); + } + kzfree(prep->payload.data[big_key_data]); +} + +/* + * dispose of the links from a revoked keyring + * - called with the key sem write-locked + */ +void big_key_revoke(struct key *key) +{ + struct path *path = (struct path *)&key->payload.data[big_key_path]; + + /* clear the quota */ + key_payload_reserve(key, 0); + if (key_is_positive(key) && + (size_t)key->payload.data[big_key_len] > BIG_KEY_FILE_THRESHOLD) + vfs_truncate(path, 0); +} + +/* + * dispose of the data dangling from the corpse of a big_key key + */ +void big_key_destroy(struct key *key) +{ + size_t datalen = (size_t)key->payload.data[big_key_len]; + + if (datalen > BIG_KEY_FILE_THRESHOLD) { + struct path *path = (struct path *)&key->payload.data[big_key_path]; + + path_put(path); + path->mnt = NULL; + path->dentry = NULL; + } + kzfree(key->payload.data[big_key_data]); + key->payload.data[big_key_data] = NULL; +} + +/* + * describe the big_key key + */ +void big_key_describe(const struct key *key, struct seq_file *m) +{ + size_t datalen = (size_t)key->payload.data[big_key_len]; + + seq_puts(m, key->description); + + if (key_is_positive(key)) + seq_printf(m, ": %zu [%s]", + datalen, + datalen > BIG_KEY_FILE_THRESHOLD ? "file" : "buff"); +} + +/* + * read the key data + * - the key's semaphore is read-locked + */ +long big_key_read(const struct key *key, char *buffer, size_t buflen) +{ + size_t datalen = (size_t)key->payload.data[big_key_len]; + long ret; + + if (!buffer || buflen < datalen) + return datalen; + + if (datalen > BIG_KEY_FILE_THRESHOLD) { + struct big_key_buf *buf; + struct path *path = (struct path *)&key->payload.data[big_key_path]; + struct file *file; + u8 *enckey = (u8 *)key->payload.data[big_key_data]; + size_t enclen = datalen + ENC_AUTHTAG_SIZE; + loff_t pos = 0; + + buf = big_key_alloc_buffer(enclen); + if (!buf) + return -ENOMEM; + + file = dentry_open(path, O_RDONLY, current_cred()); + if (IS_ERR(file)) { + ret = PTR_ERR(file); + goto error; + } + + /* read file to kernel and decrypt */ + ret = kernel_read(file, buf->virt, enclen, &pos); + if (ret >= 0 && ret != enclen) { + ret = -EIO; + goto err_fput; + } + + ret = big_key_crypt(BIG_KEY_DEC, buf, enclen, enckey); + if (ret) + goto err_fput; + + ret = datalen; + + /* copy out decrypted data */ + memcpy(buffer, buf->virt, datalen); + +err_fput: + fput(file); +error: + big_key_free_buffer(buf); + } else { + ret = datalen; + memcpy(buffer, key->payload.data[big_key_data], datalen); + } + + return ret; +} + +/* + * Register key type + */ +static int __init big_key_init(void) +{ + int ret; + + /* init block cipher */ + big_key_aead = crypto_alloc_aead(big_key_alg_name, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(big_key_aead)) { + ret = PTR_ERR(big_key_aead); + pr_err("Can't alloc crypto: %d\n", ret); + return ret; + } + + if (unlikely(crypto_aead_ivsize(big_key_aead) != BIG_KEY_IV_SIZE)) { + WARN(1, "big key algorithm changed?"); + ret = -EINVAL; + goto free_aead; + } + + ret = crypto_aead_setauthsize(big_key_aead, ENC_AUTHTAG_SIZE); + if (ret < 0) { + pr_err("Can't set crypto auth tag len: %d\n", ret); + goto free_aead; + } + + ret = register_key_type(&key_type_big_key); + if (ret < 0) { + pr_err("Can't register type: %d\n", ret); + goto free_aead; + } + + return 0; + +free_aead: + crypto_free_aead(big_key_aead); + return ret; +} + +late_initcall(big_key_init); diff --git a/security/keys/compat.c b/security/keys/compat.c new file mode 100644 index 000000000..e87c89c01 --- /dev/null +++ b/security/keys/compat.c @@ -0,0 +1,147 @@ +/* 32-bit compatibility syscall for 64-bit systems + * + * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/syscalls.h> +#include <linux/keyctl.h> +#include <linux/compat.h> +#include <linux/slab.h> +#include "internal.h" + +/* + * Instantiate a key with the specified compatibility multipart payload and + * link the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +static long compat_keyctl_instantiate_key_iov( + key_serial_t id, + const struct compat_iovec __user *_payload_iov, + unsigned ioc, + key_serial_t ringid) +{ + struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; + struct iov_iter from; + long ret; + + if (!_payload_iov) + ioc = 0; + + ret = compat_import_iovec(WRITE, _payload_iov, ioc, + ARRAY_SIZE(iovstack), &iov, + &from); + if (ret < 0) + return ret; + + ret = keyctl_instantiate_key_common(id, &from, ringid); + kfree(iov); + return ret; +} + +/* + * The key control system call, 32-bit compatibility version for 64-bit archs + * + * This should only be called if the 64-bit arch uses weird pointers in 32-bit + * mode or doesn't guarantee that the top 32-bits of the argument registers on + * taking a 32-bit syscall are zero. If you can, you should call sys_keyctl() + * directly. + */ +COMPAT_SYSCALL_DEFINE5(keyctl, u32, option, + u32, arg2, u32, arg3, u32, arg4, u32, arg5) +{ + switch (option) { + case KEYCTL_GET_KEYRING_ID: + return keyctl_get_keyring_ID(arg2, arg3); + + case KEYCTL_JOIN_SESSION_KEYRING: + return keyctl_join_session_keyring(compat_ptr(arg2)); + + case KEYCTL_UPDATE: + return keyctl_update_key(arg2, compat_ptr(arg3), arg4); + + case KEYCTL_REVOKE: + return keyctl_revoke_key(arg2); + + case KEYCTL_DESCRIBE: + return keyctl_describe_key(arg2, compat_ptr(arg3), arg4); + + case KEYCTL_CLEAR: + return keyctl_keyring_clear(arg2); + + case KEYCTL_LINK: + return keyctl_keyring_link(arg2, arg3); + + case KEYCTL_UNLINK: + return keyctl_keyring_unlink(arg2, arg3); + + case KEYCTL_SEARCH: + return keyctl_keyring_search(arg2, compat_ptr(arg3), + compat_ptr(arg4), arg5); + + case KEYCTL_READ: + return keyctl_read_key(arg2, compat_ptr(arg3), arg4); + + case KEYCTL_CHOWN: + return keyctl_chown_key(arg2, arg3, arg4); + + case KEYCTL_SETPERM: + return keyctl_setperm_key(arg2, arg3); + + case KEYCTL_INSTANTIATE: + return keyctl_instantiate_key(arg2, compat_ptr(arg3), arg4, + arg5); + + case KEYCTL_NEGATE: + return keyctl_negate_key(arg2, arg3, arg4); + + case KEYCTL_SET_REQKEY_KEYRING: + return keyctl_set_reqkey_keyring(arg2); + + case KEYCTL_SET_TIMEOUT: + return keyctl_set_timeout(arg2, arg3); + + case KEYCTL_ASSUME_AUTHORITY: + return keyctl_assume_authority(arg2); + + case KEYCTL_GET_SECURITY: + return keyctl_get_security(arg2, compat_ptr(arg3), arg4); + + case KEYCTL_SESSION_TO_PARENT: + return keyctl_session_to_parent(); + + case KEYCTL_REJECT: + return keyctl_reject_key(arg2, arg3, arg4, arg5); + + case KEYCTL_INSTANTIATE_IOV: + return compat_keyctl_instantiate_key_iov( + arg2, compat_ptr(arg3), arg4, arg5); + + case KEYCTL_INVALIDATE: + return keyctl_invalidate_key(arg2); + + case KEYCTL_GET_PERSISTENT: + return keyctl_get_persistent(arg2, arg3); + + case KEYCTL_DH_COMPUTE: + return compat_keyctl_dh_compute(compat_ptr(arg2), + compat_ptr(arg3), + arg4, compat_ptr(arg5)); + + case KEYCTL_RESTRICT_KEYRING: + return keyctl_restrict_keyring(arg2, compat_ptr(arg3), + compat_ptr(arg4)); + + default: + return -EOPNOTSUPP; + } +} diff --git a/security/keys/compat_dh.c b/security/keys/compat_dh.c new file mode 100644 index 000000000..aa6b34caf --- /dev/null +++ b/security/keys/compat_dh.c @@ -0,0 +1,40 @@ +/* 32-bit compatibility syscall for 64-bit systems for DH operations + * + * Copyright (C) 2016 Stephan Mueller <smueller@chronox.de> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/uaccess.h> + +#include "internal.h" + +/* + * Perform the DH computation or DH based key derivation. + * + * If successful, 0 will be returned. + */ +long compat_keyctl_dh_compute(struct keyctl_dh_params __user *params, + char __user *buffer, size_t buflen, + struct compat_keyctl_kdf_params __user *kdf) +{ + struct keyctl_kdf_params kdfcopy; + struct compat_keyctl_kdf_params compat_kdfcopy; + + if (!kdf) + return __keyctl_dh_compute(params, buffer, buflen, NULL); + + if (copy_from_user(&compat_kdfcopy, kdf, sizeof(compat_kdfcopy)) != 0) + return -EFAULT; + + kdfcopy.hashname = compat_ptr(compat_kdfcopy.hashname); + kdfcopy.otherinfo = compat_ptr(compat_kdfcopy.otherinfo); + kdfcopy.otherinfolen = compat_kdfcopy.otherinfolen; + memcpy(kdfcopy.__spare, compat_kdfcopy.__spare, + sizeof(kdfcopy.__spare)); + + return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy); +} diff --git a/security/keys/dh.c b/security/keys/dh.c new file mode 100644 index 000000000..711e89d8c --- /dev/null +++ b/security/keys/dh.c @@ -0,0 +1,428 @@ +/* Crypto operations using stored keys + * + * Copyright (c) 2016, Intel Corporation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/scatterlist.h> +#include <linux/crypto.h> +#include <crypto/hash.h> +#include <crypto/kpp.h> +#include <crypto/dh.h> +#include <keys/user-type.h> +#include "internal.h" + +static ssize_t dh_data_from_key(key_serial_t keyid, void **data) +{ + struct key *key; + key_ref_t key_ref; + long status; + ssize_t ret; + + key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ); + if (IS_ERR(key_ref)) { + ret = -ENOKEY; + goto error; + } + + key = key_ref_to_ptr(key_ref); + + ret = -EOPNOTSUPP; + if (key->type == &key_type_user) { + down_read(&key->sem); + status = key_validate(key); + if (status == 0) { + const struct user_key_payload *payload; + uint8_t *duplicate; + + payload = user_key_payload_locked(key); + + duplicate = kmemdup(payload->data, payload->datalen, + GFP_KERNEL); + if (duplicate) { + *data = duplicate; + ret = payload->datalen; + } else { + ret = -ENOMEM; + } + } + up_read(&key->sem); + } + + key_put(key); +error: + return ret; +} + +static void dh_free_data(struct dh *dh) +{ + kzfree(dh->key); + kzfree(dh->p); + kzfree(dh->g); +} + +struct dh_completion { + struct completion completion; + int err; +}; + +static void dh_crypto_done(struct crypto_async_request *req, int err) +{ + struct dh_completion *compl = req->data; + + if (err == -EINPROGRESS) + return; + + compl->err = err; + complete(&compl->completion); +} + +struct kdf_sdesc { + struct shash_desc shash; + char ctx[]; +}; + +static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) +{ + struct crypto_shash *tfm; + struct kdf_sdesc *sdesc; + int size; + int err; + + /* allocate synchronous hash */ + tfm = crypto_alloc_shash(hashname, 0, 0); + if (IS_ERR(tfm)) { + pr_info("could not allocate digest TFM handle %s\n", hashname); + return PTR_ERR(tfm); + } + + err = -EINVAL; + if (crypto_shash_digestsize(tfm) == 0) + goto out_free_tfm; + + err = -ENOMEM; + size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm); + sdesc = kmalloc(size, GFP_KERNEL); + if (!sdesc) + goto out_free_tfm; + sdesc->shash.tfm = tfm; + sdesc->shash.flags = 0x0; + + *sdesc_ret = sdesc; + + return 0; + +out_free_tfm: + crypto_free_shash(tfm); + return err; +} + +static void kdf_dealloc(struct kdf_sdesc *sdesc) +{ + if (!sdesc) + return; + + if (sdesc->shash.tfm) + crypto_free_shash(sdesc->shash.tfm); + + kzfree(sdesc); +} + +/* + * Implementation of the KDF in counter mode according to SP800-108 section 5.1 + * as well as SP800-56A section 5.8.1 (Single-step KDF). + * + * SP800-56A: + * The src pointer is defined as Z || other info where Z is the shared secret + * from DH and other info is an arbitrary string (see SP800-56A section + * 5.8.1.2). + * + * 'dlen' must be a multiple of the digest size. + */ +static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, + u8 *dst, unsigned int dlen, unsigned int zlen) +{ + struct shash_desc *desc = &sdesc->shash; + unsigned int h = crypto_shash_digestsize(desc->tfm); + int err = 0; + u8 *dst_orig = dst; + __be32 counter = cpu_to_be32(1); + + while (dlen) { + err = crypto_shash_init(desc); + if (err) + goto err; + + err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32)); + if (err) + goto err; + + if (zlen && h) { + u8 tmpbuffer[32]; + size_t chunk = min_t(size_t, zlen, sizeof(tmpbuffer)); + memset(tmpbuffer, 0, chunk); + + do { + err = crypto_shash_update(desc, tmpbuffer, + chunk); + if (err) + goto err; + + zlen -= chunk; + chunk = min_t(size_t, zlen, sizeof(tmpbuffer)); + } while (zlen); + } + + if (src && slen) { + err = crypto_shash_update(desc, src, slen); + if (err) + goto err; + } + + err = crypto_shash_final(desc, dst); + if (err) + goto err; + + dlen -= h; + dst += h; + counter = cpu_to_be32(be32_to_cpu(counter) + 1); + } + + return 0; + +err: + memzero_explicit(dst_orig, dlen); + return err; +} + +static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc, + char __user *buffer, size_t buflen, + uint8_t *kbuf, size_t kbuflen, size_t lzero) +{ + uint8_t *outbuf = NULL; + int ret; + size_t outbuf_len = roundup(buflen, + crypto_shash_digestsize(sdesc->shash.tfm)); + + outbuf = kmalloc(outbuf_len, GFP_KERNEL); + if (!outbuf) { + ret = -ENOMEM; + goto err; + } + + ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len, lzero); + if (ret) + goto err; + + ret = buflen; + if (copy_to_user(buffer, outbuf, buflen) != 0) + ret = -EFAULT; + +err: + kzfree(outbuf); + return ret; +} + +long __keyctl_dh_compute(struct keyctl_dh_params __user *params, + char __user *buffer, size_t buflen, + struct keyctl_kdf_params *kdfcopy) +{ + long ret; + ssize_t dlen; + int secretlen; + int outlen; + struct keyctl_dh_params pcopy; + struct dh dh_inputs; + struct scatterlist outsg; + struct dh_completion compl; + struct crypto_kpp *tfm; + struct kpp_request *req; + uint8_t *secret; + uint8_t *outbuf; + struct kdf_sdesc *sdesc = NULL; + + if (!params || (!buffer && buflen)) { + ret = -EINVAL; + goto out1; + } + if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) { + ret = -EFAULT; + goto out1; + } + + if (kdfcopy) { + char *hashname; + + if (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) { + ret = -EINVAL; + goto out1; + } + + if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN || + kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) { + ret = -EMSGSIZE; + goto out1; + } + + /* get KDF name string */ + hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME); + if (IS_ERR(hashname)) { + ret = PTR_ERR(hashname); + goto out1; + } + + /* allocate KDF from the kernel crypto API */ + ret = kdf_alloc(&sdesc, hashname); + kfree(hashname); + if (ret) + goto out1; + } + + memset(&dh_inputs, 0, sizeof(dh_inputs)); + + dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p); + if (dlen < 0) { + ret = dlen; + goto out1; + } + dh_inputs.p_size = dlen; + + dlen = dh_data_from_key(pcopy.base, &dh_inputs.g); + if (dlen < 0) { + ret = dlen; + goto out2; + } + dh_inputs.g_size = dlen; + + dlen = dh_data_from_key(pcopy.private, &dh_inputs.key); + if (dlen < 0) { + ret = dlen; + goto out2; + } + dh_inputs.key_size = dlen; + + secretlen = crypto_dh_key_len(&dh_inputs); + secret = kmalloc(secretlen, GFP_KERNEL); + if (!secret) { + ret = -ENOMEM; + goto out2; + } + ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs); + if (ret) + goto out3; + + tfm = crypto_alloc_kpp("dh", 0, 0); + if (IS_ERR(tfm)) { + ret = PTR_ERR(tfm); + goto out3; + } + + ret = crypto_kpp_set_secret(tfm, secret, secretlen); + if (ret) + goto out4; + + outlen = crypto_kpp_maxsize(tfm); + + if (!kdfcopy) { + /* + * When not using a KDF, buflen 0 is used to read the + * required buffer length + */ + if (buflen == 0) { + ret = outlen; + goto out4; + } else if (outlen > buflen) { + ret = -EOVERFLOW; + goto out4; + } + } + + outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen, + GFP_KERNEL); + if (!outbuf) { + ret = -ENOMEM; + goto out4; + } + + sg_init_one(&outsg, outbuf, outlen); + + req = kpp_request_alloc(tfm, GFP_KERNEL); + if (!req) { + ret = -ENOMEM; + goto out5; + } + + kpp_request_set_input(req, NULL, 0); + kpp_request_set_output(req, &outsg, outlen); + init_completion(&compl.completion); + kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + dh_crypto_done, &compl); + + /* + * For DH, generate_public_key and generate_shared_secret are + * the same calculation + */ + ret = crypto_kpp_generate_public_key(req); + if (ret == -EINPROGRESS) { + wait_for_completion(&compl.completion); + ret = compl.err; + if (ret) + goto out6; + } + + if (kdfcopy) { + /* + * Concatenate SP800-56A otherinfo past DH shared secret -- the + * input to the KDF is (DH shared secret || otherinfo) + */ + if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo, + kdfcopy->otherinfolen) != 0) { + ret = -EFAULT; + goto out6; + } + + ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf, + req->dst_len + kdfcopy->otherinfolen, + outlen - req->dst_len); + } else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) { + ret = req->dst_len; + } else { + ret = -EFAULT; + } + +out6: + kpp_request_free(req); +out5: + kzfree(outbuf); +out4: + crypto_free_kpp(tfm); +out3: + kzfree(secret); +out2: + dh_free_data(&dh_inputs); +out1: + kdf_dealloc(sdesc); + return ret; +} + +long keyctl_dh_compute(struct keyctl_dh_params __user *params, + char __user *buffer, size_t buflen, + struct keyctl_kdf_params __user *kdf) +{ + struct keyctl_kdf_params kdfcopy; + + if (!kdf) + return __keyctl_dh_compute(params, buffer, buflen, NULL); + + if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0) + return -EFAULT; + + return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy); +} diff --git a/security/keys/encrypted-keys/Makefile b/security/keys/encrypted-keys/Makefile new file mode 100644 index 000000000..7a44dce6f --- /dev/null +++ b/security/keys/encrypted-keys/Makefile @@ -0,0 +1,11 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for encrypted keys +# + +obj-$(CONFIG_ENCRYPTED_KEYS) += encrypted-keys.o + +encrypted-keys-y := encrypted.o ecryptfs_format.o +masterkey-$(CONFIG_TRUSTED_KEYS) := masterkey_trusted.o +masterkey-$(CONFIG_TRUSTED_KEYS)-$(CONFIG_ENCRYPTED_KEYS) := masterkey_trusted.o +encrypted-keys-y += $(masterkey-y) $(masterkey-m-m) diff --git a/security/keys/encrypted-keys/ecryptfs_format.c b/security/keys/encrypted-keys/ecryptfs_format.c new file mode 100644 index 000000000..6daa3b6ff --- /dev/null +++ b/security/keys/encrypted-keys/ecryptfs_format.c @@ -0,0 +1,81 @@ +/* + * ecryptfs_format.c: helper functions for the encrypted key type + * + * Copyright (C) 2006 International Business Machines Corp. + * Copyright (C) 2010 Politecnico di Torino, Italy + * TORSEC group -- http://security.polito.it + * + * Authors: + * Michael A. Halcrow <mahalcro@us.ibm.com> + * Tyler Hicks <tyhicks@ou.edu> + * Roberto Sassu <roberto.sassu@polito.it> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ + +#include <linux/module.h> +#include "ecryptfs_format.h" + +u8 *ecryptfs_get_auth_tok_key(struct ecryptfs_auth_tok *auth_tok) +{ + return auth_tok->token.password.session_key_encryption_key; +} +EXPORT_SYMBOL(ecryptfs_get_auth_tok_key); + +/* + * ecryptfs_get_versions() + * + * Source code taken from the software 'ecryptfs-utils' version 83. + * + */ +void ecryptfs_get_versions(int *major, int *minor, int *file_version) +{ + *major = ECRYPTFS_VERSION_MAJOR; + *minor = ECRYPTFS_VERSION_MINOR; + if (file_version) + *file_version = ECRYPTFS_SUPPORTED_FILE_VERSION; +} +EXPORT_SYMBOL(ecryptfs_get_versions); + +/* + * ecryptfs_fill_auth_tok - fill the ecryptfs_auth_tok structure + * + * Fill the ecryptfs_auth_tok structure with required ecryptfs data. + * The source code is inspired to the original function generate_payload() + * shipped with the software 'ecryptfs-utils' version 83. + * + */ +int ecryptfs_fill_auth_tok(struct ecryptfs_auth_tok *auth_tok, + const char *key_desc) +{ + int major, minor; + + ecryptfs_get_versions(&major, &minor, NULL); + auth_tok->version = (((uint16_t)(major << 8) & 0xFF00) + | ((uint16_t)minor & 0x00FF)); + auth_tok->token_type = ECRYPTFS_PASSWORD; + strncpy((char *)auth_tok->token.password.signature, key_desc, + ECRYPTFS_PASSWORD_SIG_SIZE); + auth_tok->token.password.session_key_encryption_key_bytes = + ECRYPTFS_MAX_KEY_BYTES; + /* + * Removed auth_tok->token.password.salt and + * auth_tok->token.password.session_key_encryption_key + * initialization from the original code + */ + /* TODO: Make the hash parameterizable via policy */ + auth_tok->token.password.flags |= + ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET; + /* The kernel code will encrypt the session key. */ + auth_tok->session_key.encrypted_key[0] = 0; + auth_tok->session_key.encrypted_key_size = 0; + /* Default; subject to change by kernel eCryptfs */ + auth_tok->token.password.hash_algo = PGP_DIGEST_ALGO_SHA512; + auth_tok->token.password.flags &= ~(ECRYPTFS_PERSISTENT_PASSWORD); + return 0; +} +EXPORT_SYMBOL(ecryptfs_fill_auth_tok); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/encrypted-keys/ecryptfs_format.h b/security/keys/encrypted-keys/ecryptfs_format.h new file mode 100644 index 000000000..40294de23 --- /dev/null +++ b/security/keys/encrypted-keys/ecryptfs_format.h @@ -0,0 +1,30 @@ +/* + * ecryptfs_format.h: helper functions for the encrypted key type + * + * Copyright (C) 2006 International Business Machines Corp. + * Copyright (C) 2010 Politecnico di Torino, Italy + * TORSEC group -- http://security.polito.it + * + * Authors: + * Michael A. Halcrow <mahalcro@us.ibm.com> + * Tyler Hicks <tyhicks@ou.edu> + * Roberto Sassu <roberto.sassu@polito.it> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ + +#ifndef __KEYS_ECRYPTFS_H +#define __KEYS_ECRYPTFS_H + +#include <linux/ecryptfs.h> + +#define PGP_DIGEST_ALGO_SHA512 10 + +u8 *ecryptfs_get_auth_tok_key(struct ecryptfs_auth_tok *auth_tok); +void ecryptfs_get_versions(int *major, int *minor, int *file_version); +int ecryptfs_fill_auth_tok(struct ecryptfs_auth_tok *auth_tok, + const char *key_desc); + +#endif /* __KEYS_ECRYPTFS_H */ diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c new file mode 100644 index 000000000..571f6d486 --- /dev/null +++ b/security/keys/encrypted-keys/encrypted.c @@ -0,0 +1,1015 @@ +/* + * Copyright (C) 2010 IBM Corporation + * Copyright (C) 2010 Politecnico di Torino, Italy + * TORSEC group -- http://security.polito.it + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * Roberto Sassu <roberto.sassu@polito.it> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * See Documentation/security/keys/trusted-encrypted.rst + */ + +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/parser.h> +#include <linux/string.h> +#include <linux/err.h> +#include <keys/user-type.h> +#include <keys/trusted-type.h> +#include <keys/encrypted-type.h> +#include <linux/key-type.h> +#include <linux/random.h> +#include <linux/rcupdate.h> +#include <linux/scatterlist.h> +#include <linux/ctype.h> +#include <crypto/aes.h> +#include <crypto/algapi.h> +#include <crypto/hash.h> +#include <crypto/sha.h> +#include <crypto/skcipher.h> + +#include "encrypted.h" +#include "ecryptfs_format.h" + +static const char KEY_TRUSTED_PREFIX[] = "trusted:"; +static const char KEY_USER_PREFIX[] = "user:"; +static const char hash_alg[] = "sha256"; +static const char hmac_alg[] = "hmac(sha256)"; +static const char blkcipher_alg[] = "cbc(aes)"; +static const char key_format_default[] = "default"; +static const char key_format_ecryptfs[] = "ecryptfs"; +static unsigned int ivsize; +static int blksize; + +#define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1) +#define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1) +#define KEY_ECRYPTFS_DESC_LEN 16 +#define HASH_SIZE SHA256_DIGEST_SIZE +#define MAX_DATA_SIZE 4096 +#define MIN_DATA_SIZE 20 + +static struct crypto_shash *hash_tfm; + +enum { + Opt_err = -1, Opt_new, Opt_load, Opt_update +}; + +enum { + Opt_error = -1, Opt_default, Opt_ecryptfs +}; + +static const match_table_t key_format_tokens = { + {Opt_default, "default"}, + {Opt_ecryptfs, "ecryptfs"}, + {Opt_error, NULL} +}; + +static const match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_load, "load"}, + {Opt_update, "update"}, + {Opt_err, NULL} +}; + +static int aes_get_sizes(void) +{ + struct crypto_skcipher *tfm; + + tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(tfm)) { + pr_err("encrypted_key: failed to alloc_cipher (%ld)\n", + PTR_ERR(tfm)); + return PTR_ERR(tfm); + } + ivsize = crypto_skcipher_ivsize(tfm); + blksize = crypto_skcipher_blocksize(tfm); + crypto_free_skcipher(tfm); + return 0; +} + +/* + * valid_ecryptfs_desc - verify the description of a new/loaded encrypted key + * + * The description of a encrypted key with format 'ecryptfs' must contain + * exactly 16 hexadecimal characters. + * + */ +static int valid_ecryptfs_desc(const char *ecryptfs_desc) +{ + int i; + + if (strlen(ecryptfs_desc) != KEY_ECRYPTFS_DESC_LEN) { + pr_err("encrypted_key: key description must be %d hexadecimal " + "characters long\n", KEY_ECRYPTFS_DESC_LEN); + return -EINVAL; + } + + for (i = 0; i < KEY_ECRYPTFS_DESC_LEN; i++) { + if (!isxdigit(ecryptfs_desc[i])) { + pr_err("encrypted_key: key description must contain " + "only hexadecimal characters\n"); + return -EINVAL; + } + } + + return 0; +} + +/* + * valid_master_desc - verify the 'key-type:desc' of a new/updated master-key + * + * key-type:= "trusted:" | "user:" + * desc:= master-key description + * + * Verify that 'key-type' is valid and that 'desc' exists. On key update, + * only the master key description is permitted to change, not the key-type. + * The key-type remains constant. + * + * On success returns 0, otherwise -EINVAL. + */ +static int valid_master_desc(const char *new_desc, const char *orig_desc) +{ + int prefix_len; + + if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) + prefix_len = KEY_TRUSTED_PREFIX_LEN; + else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) + prefix_len = KEY_USER_PREFIX_LEN; + else + return -EINVAL; + + if (!new_desc[prefix_len]) + return -EINVAL; + + if (orig_desc && strncmp(new_desc, orig_desc, prefix_len)) + return -EINVAL; + + return 0; +} + +/* + * datablob_parse - parse the keyctl data + * + * datablob format: + * new [<format>] <master-key name> <decrypted data length> + * load [<format>] <master-key name> <decrypted data length> + * <encrypted iv + data> + * update <new-master-key name> + * + * Tokenizes a copy of the keyctl data, returning a pointer to each token, + * which is null terminated. + * + * On success returns 0, otherwise -EINVAL. + */ +static int datablob_parse(char *datablob, const char **format, + char **master_desc, char **decrypted_datalen, + char **hex_encoded_iv) +{ + substring_t args[MAX_OPT_ARGS]; + int ret = -EINVAL; + int key_cmd; + int key_format; + char *p, *keyword; + + keyword = strsep(&datablob, " \t"); + if (!keyword) { + pr_info("encrypted_key: insufficient parameters specified\n"); + return ret; + } + key_cmd = match_token(keyword, key_tokens, args); + + /* Get optional format: default | ecryptfs */ + p = strsep(&datablob, " \t"); + if (!p) { + pr_err("encrypted_key: insufficient parameters specified\n"); + return ret; + } + + key_format = match_token(p, key_format_tokens, args); + switch (key_format) { + case Opt_ecryptfs: + case Opt_default: + *format = p; + *master_desc = strsep(&datablob, " \t"); + break; + case Opt_error: + *master_desc = p; + break; + } + + if (!*master_desc) { + pr_info("encrypted_key: master key parameter is missing\n"); + goto out; + } + + if (valid_master_desc(*master_desc, NULL) < 0) { + pr_info("encrypted_key: master key parameter \'%s\' " + "is invalid\n", *master_desc); + goto out; + } + + if (decrypted_datalen) { + *decrypted_datalen = strsep(&datablob, " \t"); + if (!*decrypted_datalen) { + pr_info("encrypted_key: keylen parameter is missing\n"); + goto out; + } + } + + switch (key_cmd) { + case Opt_new: + if (!decrypted_datalen) { + pr_info("encrypted_key: keyword \'%s\' not allowed " + "when called from .update method\n", keyword); + break; + } + ret = 0; + break; + case Opt_load: + if (!decrypted_datalen) { + pr_info("encrypted_key: keyword \'%s\' not allowed " + "when called from .update method\n", keyword); + break; + } + *hex_encoded_iv = strsep(&datablob, " \t"); + if (!*hex_encoded_iv) { + pr_info("encrypted_key: hex blob is missing\n"); + break; + } + ret = 0; + break; + case Opt_update: + if (decrypted_datalen) { + pr_info("encrypted_key: keyword \'%s\' not allowed " + "when called from .instantiate method\n", + keyword); + break; + } + ret = 0; + break; + case Opt_err: + pr_info("encrypted_key: keyword \'%s\' not recognized\n", + keyword); + break; + } +out: + return ret; +} + +/* + * datablob_format - format as an ascii string, before copying to userspace + */ +static char *datablob_format(struct encrypted_key_payload *epayload, + size_t asciiblob_len) +{ + char *ascii_buf, *bufp; + u8 *iv = epayload->iv; + int len; + int i; + + ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL); + if (!ascii_buf) + goto out; + + ascii_buf[asciiblob_len] = '\0'; + + /* copy datablob master_desc and datalen strings */ + len = sprintf(ascii_buf, "%s %s %s ", epayload->format, + epayload->master_desc, epayload->datalen); + + /* convert the hex encoded iv, encrypted-data and HMAC to ascii */ + bufp = &ascii_buf[len]; + for (i = 0; i < (asciiblob_len - len) / 2; i++) + bufp = hex_byte_pack(bufp, iv[i]); +out: + return ascii_buf; +} + +/* + * request_user_key - request the user key + * + * Use a user provided key to encrypt/decrypt an encrypted-key. + */ +static struct key *request_user_key(const char *master_desc, const u8 **master_key, + size_t *master_keylen) +{ + const struct user_key_payload *upayload; + struct key *ukey; + + ukey = request_key(&key_type_user, master_desc, NULL); + if (IS_ERR(ukey)) + goto error; + + down_read(&ukey->sem); + upayload = user_key_payload_locked(ukey); + if (!upayload) { + /* key was revoked before we acquired its semaphore */ + up_read(&ukey->sem); + key_put(ukey); + ukey = ERR_PTR(-EKEYREVOKED); + goto error; + } + *master_key = upayload->data; + *master_keylen = upayload->datalen; +error: + return ukey; +} + +static int calc_hash(struct crypto_shash *tfm, u8 *digest, + const u8 *buf, unsigned int buflen) +{ + SHASH_DESC_ON_STACK(desc, tfm); + int err; + + desc->tfm = tfm; + desc->flags = 0; + + err = crypto_shash_digest(desc, buf, buflen, digest); + shash_desc_zero(desc); + return err; +} + +static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen, + const u8 *buf, unsigned int buflen) +{ + struct crypto_shash *tfm; + int err; + + tfm = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(tfm)) { + pr_err("encrypted_key: can't alloc %s transform: %ld\n", + hmac_alg, PTR_ERR(tfm)); + return PTR_ERR(tfm); + } + + err = crypto_shash_setkey(tfm, key, keylen); + if (!err) + err = calc_hash(tfm, digest, buf, buflen); + crypto_free_shash(tfm); + return err; +} + +enum derived_key_type { ENC_KEY, AUTH_KEY }; + +/* Derive authentication/encryption key from trusted key */ +static int get_derived_key(u8 *derived_key, enum derived_key_type key_type, + const u8 *master_key, size_t master_keylen) +{ + u8 *derived_buf; + unsigned int derived_buf_len; + int ret; + + derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen; + if (derived_buf_len < HASH_SIZE) + derived_buf_len = HASH_SIZE; + + derived_buf = kzalloc(derived_buf_len, GFP_KERNEL); + if (!derived_buf) + return -ENOMEM; + + if (key_type) + strcpy(derived_buf, "AUTH_KEY"); + else + strcpy(derived_buf, "ENC_KEY"); + + memcpy(derived_buf + strlen(derived_buf) + 1, master_key, + master_keylen); + ret = calc_hash(hash_tfm, derived_key, derived_buf, derived_buf_len); + kzfree(derived_buf); + return ret; +} + +static struct skcipher_request *init_skcipher_req(const u8 *key, + unsigned int key_len) +{ + struct skcipher_request *req; + struct crypto_skcipher *tfm; + int ret; + + tfm = crypto_alloc_skcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(tfm)) { + pr_err("encrypted_key: failed to load %s transform (%ld)\n", + blkcipher_alg, PTR_ERR(tfm)); + return ERR_CAST(tfm); + } + + ret = crypto_skcipher_setkey(tfm, key, key_len); + if (ret < 0) { + pr_err("encrypted_key: failed to setkey (%d)\n", ret); + crypto_free_skcipher(tfm); + return ERR_PTR(ret); + } + + req = skcipher_request_alloc(tfm, GFP_KERNEL); + if (!req) { + pr_err("encrypted_key: failed to allocate request for %s\n", + blkcipher_alg); + crypto_free_skcipher(tfm); + return ERR_PTR(-ENOMEM); + } + + skcipher_request_set_callback(req, 0, NULL, NULL); + return req; +} + +static struct key *request_master_key(struct encrypted_key_payload *epayload, + const u8 **master_key, size_t *master_keylen) +{ + struct key *mkey = ERR_PTR(-EINVAL); + + if (!strncmp(epayload->master_desc, KEY_TRUSTED_PREFIX, + KEY_TRUSTED_PREFIX_LEN)) { + mkey = request_trusted_key(epayload->master_desc + + KEY_TRUSTED_PREFIX_LEN, + master_key, master_keylen); + } else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX, + KEY_USER_PREFIX_LEN)) { + mkey = request_user_key(epayload->master_desc + + KEY_USER_PREFIX_LEN, + master_key, master_keylen); + } else + goto out; + + if (IS_ERR(mkey)) { + int ret = PTR_ERR(mkey); + + if (ret == -ENOTSUPP) + pr_info("encrypted_key: key %s not supported", + epayload->master_desc); + else + pr_info("encrypted_key: key %s not found", + epayload->master_desc); + goto out; + } + + dump_master_key(*master_key, *master_keylen); +out: + return mkey; +} + +/* Before returning data to userspace, encrypt decrypted data. */ +static int derived_key_encrypt(struct encrypted_key_payload *epayload, + const u8 *derived_key, + unsigned int derived_keylen) +{ + struct scatterlist sg_in[2]; + struct scatterlist sg_out[1]; + struct crypto_skcipher *tfm; + struct skcipher_request *req; + unsigned int encrypted_datalen; + u8 iv[AES_BLOCK_SIZE]; + int ret; + + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); + + req = init_skcipher_req(derived_key, derived_keylen); + ret = PTR_ERR(req); + if (IS_ERR(req)) + goto out; + dump_decrypted_data(epayload); + + sg_init_table(sg_in, 2); + sg_set_buf(&sg_in[0], epayload->decrypted_data, + epayload->decrypted_datalen); + sg_set_page(&sg_in[1], ZERO_PAGE(0), AES_BLOCK_SIZE, 0); + + sg_init_table(sg_out, 1); + sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen); + + memcpy(iv, epayload->iv, sizeof(iv)); + skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv); + ret = crypto_skcipher_encrypt(req); + tfm = crypto_skcipher_reqtfm(req); + skcipher_request_free(req); + crypto_free_skcipher(tfm); + if (ret < 0) + pr_err("encrypted_key: failed to encrypt (%d)\n", ret); + else + dump_encrypted_data(epayload, encrypted_datalen); +out: + return ret; +} + +static int datablob_hmac_append(struct encrypted_key_payload *epayload, + const u8 *master_key, size_t master_keylen) +{ + u8 derived_key[HASH_SIZE]; + u8 *digest; + int ret; + + ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + digest = epayload->format + epayload->datablob_len; + ret = calc_hmac(digest, derived_key, sizeof derived_key, + epayload->format, epayload->datablob_len); + if (!ret) + dump_hmac(NULL, digest, HASH_SIZE); +out: + memzero_explicit(derived_key, sizeof(derived_key)); + return ret; +} + +/* verify HMAC before decrypting encrypted key */ +static int datablob_hmac_verify(struct encrypted_key_payload *epayload, + const u8 *format, const u8 *master_key, + size_t master_keylen) +{ + u8 derived_key[HASH_SIZE]; + u8 digest[HASH_SIZE]; + int ret; + char *p; + unsigned short len; + + ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + len = epayload->datablob_len; + if (!format) { + p = epayload->master_desc; + len -= strlen(epayload->format) + 1; + } else + p = epayload->format; + + ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len); + if (ret < 0) + goto out; + ret = crypto_memneq(digest, epayload->format + epayload->datablob_len, + sizeof(digest)); + if (ret) { + ret = -EINVAL; + dump_hmac("datablob", + epayload->format + epayload->datablob_len, + HASH_SIZE); + dump_hmac("calc", digest, HASH_SIZE); + } +out: + memzero_explicit(derived_key, sizeof(derived_key)); + return ret; +} + +static int derived_key_decrypt(struct encrypted_key_payload *epayload, + const u8 *derived_key, + unsigned int derived_keylen) +{ + struct scatterlist sg_in[1]; + struct scatterlist sg_out[2]; + struct crypto_skcipher *tfm; + struct skcipher_request *req; + unsigned int encrypted_datalen; + u8 iv[AES_BLOCK_SIZE]; + u8 *pad; + int ret; + + /* Throwaway buffer to hold the unused zero padding at the end */ + pad = kmalloc(AES_BLOCK_SIZE, GFP_KERNEL); + if (!pad) + return -ENOMEM; + + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); + req = init_skcipher_req(derived_key, derived_keylen); + ret = PTR_ERR(req); + if (IS_ERR(req)) + goto out; + dump_encrypted_data(epayload, encrypted_datalen); + + sg_init_table(sg_in, 1); + sg_init_table(sg_out, 2); + sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen); + sg_set_buf(&sg_out[0], epayload->decrypted_data, + epayload->decrypted_datalen); + sg_set_buf(&sg_out[1], pad, AES_BLOCK_SIZE); + + memcpy(iv, epayload->iv, sizeof(iv)); + skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv); + ret = crypto_skcipher_decrypt(req); + tfm = crypto_skcipher_reqtfm(req); + skcipher_request_free(req); + crypto_free_skcipher(tfm); + if (ret < 0) + goto out; + dump_decrypted_data(epayload); +out: + kfree(pad); + return ret; +} + +/* Allocate memory for decrypted key and datablob. */ +static struct encrypted_key_payload *encrypted_key_alloc(struct key *key, + const char *format, + const char *master_desc, + const char *datalen) +{ + struct encrypted_key_payload *epayload = NULL; + unsigned short datablob_len; + unsigned short decrypted_datalen; + unsigned short payload_datalen; + unsigned int encrypted_datalen; + unsigned int format_len; + long dlen; + int ret; + + ret = kstrtol(datalen, 10, &dlen); + if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE) + return ERR_PTR(-EINVAL); + + format_len = (!format) ? strlen(key_format_default) : strlen(format); + decrypted_datalen = dlen; + payload_datalen = decrypted_datalen; + if (format && !strcmp(format, key_format_ecryptfs)) { + if (dlen != ECRYPTFS_MAX_KEY_BYTES) { + pr_err("encrypted_key: keylen for the ecryptfs format " + "must be equal to %d bytes\n", + ECRYPTFS_MAX_KEY_BYTES); + return ERR_PTR(-EINVAL); + } + decrypted_datalen = ECRYPTFS_MAX_KEY_BYTES; + payload_datalen = sizeof(struct ecryptfs_auth_tok); + } + + encrypted_datalen = roundup(decrypted_datalen, blksize); + + datablob_len = format_len + 1 + strlen(master_desc) + 1 + + strlen(datalen) + 1 + ivsize + 1 + encrypted_datalen; + + ret = key_payload_reserve(key, payload_datalen + datablob_len + + HASH_SIZE + 1); + if (ret < 0) + return ERR_PTR(ret); + + epayload = kzalloc(sizeof(*epayload) + payload_datalen + + datablob_len + HASH_SIZE + 1, GFP_KERNEL); + if (!epayload) + return ERR_PTR(-ENOMEM); + + epayload->payload_datalen = payload_datalen; + epayload->decrypted_datalen = decrypted_datalen; + epayload->datablob_len = datablob_len; + return epayload; +} + +static int encrypted_key_decrypt(struct encrypted_key_payload *epayload, + const char *format, const char *hex_encoded_iv) +{ + struct key *mkey; + u8 derived_key[HASH_SIZE]; + const u8 *master_key; + u8 *hmac; + const char *hex_encoded_data; + unsigned int encrypted_datalen; + size_t master_keylen; + size_t asciilen; + int ret; + + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); + asciilen = (ivsize + 1 + encrypted_datalen + HASH_SIZE) * 2; + if (strlen(hex_encoded_iv) != asciilen) + return -EINVAL; + + hex_encoded_data = hex_encoded_iv + (2 * ivsize) + 2; + ret = hex2bin(epayload->iv, hex_encoded_iv, ivsize); + if (ret < 0) + return -EINVAL; + ret = hex2bin(epayload->encrypted_data, hex_encoded_data, + encrypted_datalen); + if (ret < 0) + return -EINVAL; + + hmac = epayload->format + epayload->datablob_len; + ret = hex2bin(hmac, hex_encoded_data + (encrypted_datalen * 2), + HASH_SIZE); + if (ret < 0) + return -EINVAL; + + mkey = request_master_key(epayload, &master_key, &master_keylen); + if (IS_ERR(mkey)) + return PTR_ERR(mkey); + + ret = datablob_hmac_verify(epayload, format, master_key, master_keylen); + if (ret < 0) { + pr_err("encrypted_key: bad hmac (%d)\n", ret); + goto out; + } + + ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + ret = derived_key_decrypt(epayload, derived_key, sizeof derived_key); + if (ret < 0) + pr_err("encrypted_key: failed to decrypt key (%d)\n", ret); +out: + up_read(&mkey->sem); + key_put(mkey); + memzero_explicit(derived_key, sizeof(derived_key)); + return ret; +} + +static void __ekey_init(struct encrypted_key_payload *epayload, + const char *format, const char *master_desc, + const char *datalen) +{ + unsigned int format_len; + + format_len = (!format) ? strlen(key_format_default) : strlen(format); + epayload->format = epayload->payload_data + epayload->payload_datalen; + epayload->master_desc = epayload->format + format_len + 1; + epayload->datalen = epayload->master_desc + strlen(master_desc) + 1; + epayload->iv = epayload->datalen + strlen(datalen) + 1; + epayload->encrypted_data = epayload->iv + ivsize + 1; + epayload->decrypted_data = epayload->payload_data; + + if (!format) + memcpy(epayload->format, key_format_default, format_len); + else { + if (!strcmp(format, key_format_ecryptfs)) + epayload->decrypted_data = + ecryptfs_get_auth_tok_key((struct ecryptfs_auth_tok *)epayload->payload_data); + + memcpy(epayload->format, format, format_len); + } + + memcpy(epayload->master_desc, master_desc, strlen(master_desc)); + memcpy(epayload->datalen, datalen, strlen(datalen)); +} + +/* + * encrypted_init - initialize an encrypted key + * + * For a new key, use a random number for both the iv and data + * itself. For an old key, decrypt the hex encoded data. + */ +static int encrypted_init(struct encrypted_key_payload *epayload, + const char *key_desc, const char *format, + const char *master_desc, const char *datalen, + const char *hex_encoded_iv) +{ + int ret = 0; + + if (format && !strcmp(format, key_format_ecryptfs)) { + ret = valid_ecryptfs_desc(key_desc); + if (ret < 0) + return ret; + + ecryptfs_fill_auth_tok((struct ecryptfs_auth_tok *)epayload->payload_data, + key_desc); + } + + __ekey_init(epayload, format, master_desc, datalen); + if (!hex_encoded_iv) { + get_random_bytes(epayload->iv, ivsize); + + get_random_bytes(epayload->decrypted_data, + epayload->decrypted_datalen); + } else + ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv); + return ret; +} + +/* + * encrypted_instantiate - instantiate an encrypted key + * + * Decrypt an existing encrypted datablob or create a new encrypted key + * based on a kernel random number. + * + * On success, return 0. Otherwise return errno. + */ +static int encrypted_instantiate(struct key *key, + struct key_preparsed_payload *prep) +{ + struct encrypted_key_payload *epayload = NULL; + char *datablob = NULL; + const char *format = NULL; + char *master_desc = NULL; + char *decrypted_datalen = NULL; + char *hex_encoded_iv = NULL; + size_t datalen = prep->datalen; + int ret; + + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + datablob[datalen] = 0; + memcpy(datablob, prep->data, datalen); + ret = datablob_parse(datablob, &format, &master_desc, + &decrypted_datalen, &hex_encoded_iv); + if (ret < 0) + goto out; + + epayload = encrypted_key_alloc(key, format, master_desc, + decrypted_datalen); + if (IS_ERR(epayload)) { + ret = PTR_ERR(epayload); + goto out; + } + ret = encrypted_init(epayload, key->description, format, master_desc, + decrypted_datalen, hex_encoded_iv); + if (ret < 0) { + kzfree(epayload); + goto out; + } + + rcu_assign_keypointer(key, epayload); +out: + kzfree(datablob); + return ret; +} + +static void encrypted_rcu_free(struct rcu_head *rcu) +{ + struct encrypted_key_payload *epayload; + + epayload = container_of(rcu, struct encrypted_key_payload, rcu); + kzfree(epayload); +} + +/* + * encrypted_update - update the master key description + * + * Change the master key description for an existing encrypted key. + * The next read will return an encrypted datablob using the new + * master key description. + * + * On success, return 0. Otherwise return errno. + */ +static int encrypted_update(struct key *key, struct key_preparsed_payload *prep) +{ + struct encrypted_key_payload *epayload = key->payload.data[0]; + struct encrypted_key_payload *new_epayload; + char *buf; + char *new_master_desc = NULL; + const char *format = NULL; + size_t datalen = prep->datalen; + int ret = 0; + + if (key_is_negative(key)) + return -ENOKEY; + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + buf = kmalloc(datalen + 1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + buf[datalen] = 0; + memcpy(buf, prep->data, datalen); + ret = datablob_parse(buf, &format, &new_master_desc, NULL, NULL); + if (ret < 0) + goto out; + + ret = valid_master_desc(new_master_desc, epayload->master_desc); + if (ret < 0) + goto out; + + new_epayload = encrypted_key_alloc(key, epayload->format, + new_master_desc, epayload->datalen); + if (IS_ERR(new_epayload)) { + ret = PTR_ERR(new_epayload); + goto out; + } + + __ekey_init(new_epayload, epayload->format, new_master_desc, + epayload->datalen); + + memcpy(new_epayload->iv, epayload->iv, ivsize); + memcpy(new_epayload->payload_data, epayload->payload_data, + epayload->payload_datalen); + + rcu_assign_keypointer(key, new_epayload); + call_rcu(&epayload->rcu, encrypted_rcu_free); +out: + kzfree(buf); + return ret; +} + +/* + * encrypted_read - format and copy out the encrypted data + * + * The resulting datablob format is: + * <master-key name> <decrypted data length> <encrypted iv> <encrypted data> + * + * On success, return to userspace the encrypted key datablob size. + */ +static long encrypted_read(const struct key *key, char *buffer, + size_t buflen) +{ + struct encrypted_key_payload *epayload; + struct key *mkey; + const u8 *master_key; + size_t master_keylen; + char derived_key[HASH_SIZE]; + char *ascii_buf; + size_t asciiblob_len; + int ret; + + epayload = dereference_key_locked(key); + + /* returns the hex encoded iv, encrypted-data, and hmac as ascii */ + asciiblob_len = epayload->datablob_len + ivsize + 1 + + roundup(epayload->decrypted_datalen, blksize) + + (HASH_SIZE * 2); + + if (!buffer || buflen < asciiblob_len) + return asciiblob_len; + + mkey = request_master_key(epayload, &master_key, &master_keylen); + if (IS_ERR(mkey)) + return PTR_ERR(mkey); + + ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key); + if (ret < 0) + goto out; + + ret = datablob_hmac_append(epayload, master_key, master_keylen); + if (ret < 0) + goto out; + + ascii_buf = datablob_format(epayload, asciiblob_len); + if (!ascii_buf) { + ret = -ENOMEM; + goto out; + } + + up_read(&mkey->sem); + key_put(mkey); + memzero_explicit(derived_key, sizeof(derived_key)); + + memcpy(buffer, ascii_buf, asciiblob_len); + kzfree(ascii_buf); + + return asciiblob_len; +out: + up_read(&mkey->sem); + key_put(mkey); + memzero_explicit(derived_key, sizeof(derived_key)); + return ret; +} + +/* + * encrypted_destroy - clear and free the key's payload + */ +static void encrypted_destroy(struct key *key) +{ + kzfree(key->payload.data[0]); +} + +struct key_type key_type_encrypted = { + .name = "encrypted", + .instantiate = encrypted_instantiate, + .update = encrypted_update, + .destroy = encrypted_destroy, + .describe = user_describe, + .read = encrypted_read, +}; +EXPORT_SYMBOL_GPL(key_type_encrypted); + +static int __init init_encrypted(void) +{ + int ret; + + hash_tfm = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hash_tfm)) { + pr_err("encrypted_key: can't allocate %s transform: %ld\n", + hash_alg, PTR_ERR(hash_tfm)); + return PTR_ERR(hash_tfm); + } + + ret = aes_get_sizes(); + if (ret < 0) + goto out; + ret = register_key_type(&key_type_encrypted); + if (ret < 0) + goto out; + return 0; +out: + crypto_free_shash(hash_tfm); + return ret; + +} + +static void __exit cleanup_encrypted(void) +{ + crypto_free_shash(hash_tfm); + unregister_key_type(&key_type_encrypted); +} + +late_initcall(init_encrypted); +module_exit(cleanup_encrypted); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/encrypted-keys/encrypted.h b/security/keys/encrypted-keys/encrypted.h new file mode 100644 index 000000000..1809995db --- /dev/null +++ b/security/keys/encrypted-keys/encrypted.h @@ -0,0 +1,67 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ENCRYPTED_KEY_H +#define __ENCRYPTED_KEY_H + +#define ENCRYPTED_DEBUG 0 +#if defined(CONFIG_TRUSTED_KEYS) || \ + (defined(CONFIG_TRUSTED_KEYS_MODULE) && defined(CONFIG_ENCRYPTED_KEYS_MODULE)) +extern struct key *request_trusted_key(const char *trusted_desc, + const u8 **master_key, size_t *master_keylen); +#else +static inline struct key *request_trusted_key(const char *trusted_desc, + const u8 **master_key, + size_t *master_keylen) +{ + return ERR_PTR(-EOPNOTSUPP); +} +#endif + +#if ENCRYPTED_DEBUG +static inline void dump_master_key(const u8 *master_key, size_t master_keylen) +{ + print_hex_dump(KERN_ERR, "master key: ", DUMP_PREFIX_NONE, 32, 1, + master_key, master_keylen, 0); +} + +static inline void dump_decrypted_data(struct encrypted_key_payload *epayload) +{ + print_hex_dump(KERN_ERR, "decrypted data: ", DUMP_PREFIX_NONE, 32, 1, + epayload->decrypted_data, + epayload->decrypted_datalen, 0); +} + +static inline void dump_encrypted_data(struct encrypted_key_payload *epayload, + unsigned int encrypted_datalen) +{ + print_hex_dump(KERN_ERR, "encrypted data: ", DUMP_PREFIX_NONE, 32, 1, + epayload->encrypted_data, encrypted_datalen, 0); +} + +static inline void dump_hmac(const char *str, const u8 *digest, + unsigned int hmac_size) +{ + if (str) + pr_info("encrypted_key: %s", str); + print_hex_dump(KERN_ERR, "hmac: ", DUMP_PREFIX_NONE, 32, 1, digest, + hmac_size, 0); +} +#else +static inline void dump_master_key(const u8 *master_key, size_t master_keylen) +{ +} + +static inline void dump_decrypted_data(struct encrypted_key_payload *epayload) +{ +} + +static inline void dump_encrypted_data(struct encrypted_key_payload *epayload, + unsigned int encrypted_datalen) +{ +} + +static inline void dump_hmac(const char *str, const u8 *digest, + unsigned int hmac_size) +{ +} +#endif +#endif diff --git a/security/keys/encrypted-keys/masterkey_trusted.c b/security/keys/encrypted-keys/masterkey_trusted.c new file mode 100644 index 000000000..cbf0bc127 --- /dev/null +++ b/security/keys/encrypted-keys/masterkey_trusted.c @@ -0,0 +1,47 @@ +/* + * Copyright (C) 2010 IBM Corporation + * Copyright (C) 2010 Politecnico di Torino, Italy + * TORSEC group -- http://security.polito.it + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * Roberto Sassu <roberto.sassu@polito.it> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * See Documentation/security/keys/trusted-encrypted.rst + */ + +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/err.h> +#include <keys/trusted-type.h> +#include <keys/encrypted-type.h> +#include "encrypted.h" + +/* + * request_trusted_key - request the trusted key + * + * Trusted keys are sealed to PCRs and other metadata. Although userspace + * manages both trusted/encrypted key-types, like the encrypted key type + * data, trusted key type data is not visible decrypted from userspace. + */ +struct key *request_trusted_key(const char *trusted_desc, + const u8 **master_key, size_t *master_keylen) +{ + struct trusted_key_payload *tpayload; + struct key *tkey; + + tkey = request_key(&key_type_trusted, trusted_desc, NULL); + if (IS_ERR(tkey)) + goto error; + + down_read(&tkey->sem); + tpayload = tkey->payload.data[0]; + *master_key = tpayload->key; + *master_keylen = tpayload->key_len; +error: + return tkey; +} diff --git a/security/keys/gc.c b/security/keys/gc.c new file mode 100644 index 000000000..7207e6094 --- /dev/null +++ b/security/keys/gc.c @@ -0,0 +1,369 @@ +/* Key garbage collector + * + * Copyright (C) 2009-2011 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/security.h> +#include <keys/keyring-type.h> +#include "internal.h" + +/* + * Delay between key revocation/expiry in seconds + */ +unsigned key_gc_delay = 5 * 60; + +/* + * Reaper for unused keys. + */ +static void key_garbage_collector(struct work_struct *work); +DECLARE_WORK(key_gc_work, key_garbage_collector); + +/* + * Reaper for links from keyrings to dead keys. + */ +static void key_gc_timer_func(struct timer_list *); +static DEFINE_TIMER(key_gc_timer, key_gc_timer_func); + +static time64_t key_gc_next_run = TIME64_MAX; +static struct key_type *key_gc_dead_keytype; + +static unsigned long key_gc_flags; +#define KEY_GC_KEY_EXPIRED 0 /* A key expired and needs unlinking */ +#define KEY_GC_REAP_KEYTYPE 1 /* A keytype is being unregistered */ +#define KEY_GC_REAPING_KEYTYPE 2 /* Cleared when keytype reaped */ + + +/* + * Any key whose type gets unregistered will be re-typed to this if it can't be + * immediately unlinked. + */ +struct key_type key_type_dead = { + .name = ".dead", +}; + +/* + * Schedule a garbage collection run. + * - time precision isn't particularly important + */ +void key_schedule_gc(time64_t gc_at) +{ + unsigned long expires; + time64_t now = ktime_get_real_seconds(); + + kenter("%lld", gc_at - now); + + if (gc_at <= now || test_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags)) { + kdebug("IMMEDIATE"); + schedule_work(&key_gc_work); + } else if (gc_at < key_gc_next_run) { + kdebug("DEFERRED"); + key_gc_next_run = gc_at; + expires = jiffies + (gc_at - now) * HZ; + mod_timer(&key_gc_timer, expires); + } +} + +/* + * Schedule a dead links collection run. + */ +void key_schedule_gc_links(void) +{ + set_bit(KEY_GC_KEY_EXPIRED, &key_gc_flags); + schedule_work(&key_gc_work); +} + +/* + * Some key's cleanup time was met after it expired, so we need to get the + * reaper to go through a cycle finding expired keys. + */ +static void key_gc_timer_func(struct timer_list *unused) +{ + kenter(""); + key_gc_next_run = TIME64_MAX; + key_schedule_gc_links(); +} + +/* + * Reap keys of dead type. + * + * We use three flags to make sure we see three complete cycles of the garbage + * collector: the first to mark keys of that type as being dead, the second to + * collect dead links and the third to clean up the dead keys. We have to be + * careful as there may already be a cycle in progress. + * + * The caller must be holding key_types_sem. + */ +void key_gc_keytype(struct key_type *ktype) +{ + kenter("%s", ktype->name); + + key_gc_dead_keytype = ktype; + set_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); + smp_mb(); + set_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags); + + kdebug("schedule"); + schedule_work(&key_gc_work); + + kdebug("sleep"); + wait_on_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE, + TASK_UNINTERRUPTIBLE); + + key_gc_dead_keytype = NULL; + kleave(""); +} + +/* + * Garbage collect a list of unreferenced, detached keys + */ +static noinline void key_gc_unused_keys(struct list_head *keys) +{ + while (!list_empty(keys)) { + struct key *key = + list_entry(keys->next, struct key, graveyard_link); + short state = key->state; + + list_del(&key->graveyard_link); + + kdebug("- %u", key->serial); + key_check(key); + + /* Throw away the key data if the key is instantiated */ + if (state == KEY_IS_POSITIVE && key->type->destroy) + key->type->destroy(key); + + security_key_free(key); + + /* deal with the user's key tracking and quota */ + if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { + spin_lock(&key->user->lock); + key->user->qnkeys--; + key->user->qnbytes -= key->quotalen; + spin_unlock(&key->user->lock); + } + + atomic_dec(&key->user->nkeys); + if (state != KEY_IS_UNINSTANTIATED) + atomic_dec(&key->user->nikeys); + + key_user_put(key->user); + + kfree(key->description); + + memzero_explicit(key, sizeof(*key)); + kmem_cache_free(key_jar, key); + } +} + +/* + * Garbage collector for unused keys. + * + * This is done in process context so that we don't have to disable interrupts + * all over the place. key_put() schedules this rather than trying to do the + * cleanup itself, which means key_put() doesn't have to sleep. + */ +static void key_garbage_collector(struct work_struct *work) +{ + static LIST_HEAD(graveyard); + static u8 gc_state; /* Internal persistent state */ +#define KEY_GC_REAP_AGAIN 0x01 /* - Need another cycle */ +#define KEY_GC_REAPING_LINKS 0x02 /* - We need to reap links */ +#define KEY_GC_SET_TIMER 0x04 /* - We need to restart the timer */ +#define KEY_GC_REAPING_DEAD_1 0x10 /* - We need to mark dead keys */ +#define KEY_GC_REAPING_DEAD_2 0x20 /* - We need to reap dead key links */ +#define KEY_GC_REAPING_DEAD_3 0x40 /* - We need to reap dead keys */ +#define KEY_GC_FOUND_DEAD_KEY 0x80 /* - We found at least one dead key */ + + struct rb_node *cursor; + struct key *key; + time64_t new_timer, limit; + + kenter("[%lx,%x]", key_gc_flags, gc_state); + + limit = ktime_get_real_seconds(); + if (limit > key_gc_delay) + limit -= key_gc_delay; + else + limit = key_gc_delay; + + /* Work out what we're going to be doing in this pass */ + gc_state &= KEY_GC_REAPING_DEAD_1 | KEY_GC_REAPING_DEAD_2; + gc_state <<= 1; + if (test_and_clear_bit(KEY_GC_KEY_EXPIRED, &key_gc_flags)) + gc_state |= KEY_GC_REAPING_LINKS | KEY_GC_SET_TIMER; + + if (test_and_clear_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags)) + gc_state |= KEY_GC_REAPING_DEAD_1; + kdebug("new pass %x", gc_state); + + new_timer = TIME64_MAX; + + /* As only this function is permitted to remove things from the key + * serial tree, if cursor is non-NULL then it will always point to a + * valid node in the tree - even if lock got dropped. + */ + spin_lock(&key_serial_lock); + cursor = rb_first(&key_serial_tree); + +continue_scanning: + while (cursor) { + key = rb_entry(cursor, struct key, serial_node); + cursor = rb_next(cursor); + + if (refcount_read(&key->usage) == 0) + goto found_unreferenced_key; + + if (unlikely(gc_state & KEY_GC_REAPING_DEAD_1)) { + if (key->type == key_gc_dead_keytype) { + gc_state |= KEY_GC_FOUND_DEAD_KEY; + set_bit(KEY_FLAG_DEAD, &key->flags); + key->perm = 0; + goto skip_dead_key; + } else if (key->type == &key_type_keyring && + key->restrict_link) { + goto found_restricted_keyring; + } + } + + if (gc_state & KEY_GC_SET_TIMER) { + if (key->expiry > limit && key->expiry < new_timer) { + kdebug("will expire %x in %lld", + key_serial(key), key->expiry - limit); + new_timer = key->expiry; + } + } + + if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2)) + if (key->type == key_gc_dead_keytype) + gc_state |= KEY_GC_FOUND_DEAD_KEY; + + if ((gc_state & KEY_GC_REAPING_LINKS) || + unlikely(gc_state & KEY_GC_REAPING_DEAD_2)) { + if (key->type == &key_type_keyring) + goto found_keyring; + } + + if (unlikely(gc_state & KEY_GC_REAPING_DEAD_3)) + if (key->type == key_gc_dead_keytype) + goto destroy_dead_key; + + skip_dead_key: + if (spin_is_contended(&key_serial_lock) || need_resched()) + goto contended; + } + +contended: + spin_unlock(&key_serial_lock); + +maybe_resched: + if (cursor) { + cond_resched(); + spin_lock(&key_serial_lock); + goto continue_scanning; + } + + /* We've completed the pass. Set the timer if we need to and queue a + * new cycle if necessary. We keep executing cycles until we find one + * where we didn't reap any keys. + */ + kdebug("pass complete"); + + if (gc_state & KEY_GC_SET_TIMER && new_timer != (time64_t)TIME64_MAX) { + new_timer += key_gc_delay; + key_schedule_gc(new_timer); + } + + if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2) || + !list_empty(&graveyard)) { + /* Make sure that all pending keyring payload destructions are + * fulfilled and that people aren't now looking at dead or + * dying keys that they don't have a reference upon or a link + * to. + */ + kdebug("gc sync"); + synchronize_rcu(); + } + + if (!list_empty(&graveyard)) { + kdebug("gc keys"); + key_gc_unused_keys(&graveyard); + } + + if (unlikely(gc_state & (KEY_GC_REAPING_DEAD_1 | + KEY_GC_REAPING_DEAD_2))) { + if (!(gc_state & KEY_GC_FOUND_DEAD_KEY)) { + /* No remaining dead keys: short circuit the remaining + * keytype reap cycles. + */ + kdebug("dead short"); + gc_state &= ~(KEY_GC_REAPING_DEAD_1 | KEY_GC_REAPING_DEAD_2); + gc_state |= KEY_GC_REAPING_DEAD_3; + } else { + gc_state |= KEY_GC_REAP_AGAIN; + } + } + + if (unlikely(gc_state & KEY_GC_REAPING_DEAD_3)) { + kdebug("dead wake"); + smp_mb(); + clear_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); + wake_up_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE); + } + + if (gc_state & KEY_GC_REAP_AGAIN) + schedule_work(&key_gc_work); + kleave(" [end %x]", gc_state); + return; + + /* We found an unreferenced key - once we've removed it from the tree, + * we can safely drop the lock. + */ +found_unreferenced_key: + kdebug("unrefd key %d", key->serial); + rb_erase(&key->serial_node, &key_serial_tree); + spin_unlock(&key_serial_lock); + + list_add_tail(&key->graveyard_link, &graveyard); + gc_state |= KEY_GC_REAP_AGAIN; + goto maybe_resched; + + /* We found a restricted keyring and need to update the restriction if + * it is associated with the dead key type. + */ +found_restricted_keyring: + spin_unlock(&key_serial_lock); + keyring_restriction_gc(key, key_gc_dead_keytype); + goto maybe_resched; + + /* We found a keyring and we need to check the payload for links to + * dead or expired keys. We don't flag another reap immediately as we + * have to wait for the old payload to be destroyed by RCU before we + * can reap the keys to which it refers. + */ +found_keyring: + spin_unlock(&key_serial_lock); + keyring_gc(key, limit); + goto maybe_resched; + + /* We found a dead key that is still referenced. Reset its type and + * destroy its payload with its semaphore held. + */ +destroy_dead_key: + spin_unlock(&key_serial_lock); + kdebug("destroy key %d", key->serial); + down_write(&key->sem); + key->type = &key_type_dead; + if (key_gc_dead_keytype->destroy) + key_gc_dead_keytype->destroy(key); + memset(&key->payload, KEY_DESTROY, sizeof(key->payload)); + up_write(&key->sem); + goto maybe_resched; +} diff --git a/security/keys/internal.h b/security/keys/internal.h new file mode 100644 index 000000000..d1b9c5957 --- /dev/null +++ b/security/keys/internal.h @@ -0,0 +1,309 @@ +/* Authentication token and access key management internal defs + * + * Copyright (C) 2003-5, 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _INTERNAL_H +#define _INTERNAL_H + +#include <linux/sched.h> +#include <linux/wait_bit.h> +#include <linux/cred.h> +#include <linux/key-type.h> +#include <linux/task_work.h> +#include <linux/keyctl.h> +#include <linux/refcount.h> +#include <linux/compat.h> +#include <linux/mm.h> +#include <linux/vmalloc.h> + +struct iovec; + +#ifdef __KDEBUG +#define kenter(FMT, ...) \ + printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) \ + printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__) +#define kdebug(FMT, ...) \ + printk(KERN_DEBUG " "FMT"\n", ##__VA_ARGS__) +#else +#define kenter(FMT, ...) \ + no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) \ + no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__) +#define kdebug(FMT, ...) \ + no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__) +#endif + +extern struct key_type key_type_dead; +extern struct key_type key_type_user; +extern struct key_type key_type_logon; + +/*****************************************************************************/ +/* + * Keep track of keys for a user. + * + * This needs to be separate to user_struct to avoid a refcount-loop + * (user_struct pins some keyrings which pin this struct). + * + * We also keep track of keys under request from userspace for this UID here. + */ +struct key_user { + struct rb_node node; + struct mutex cons_lock; /* construction initiation lock */ + spinlock_t lock; + refcount_t usage; /* for accessing qnkeys & qnbytes */ + atomic_t nkeys; /* number of keys */ + atomic_t nikeys; /* number of instantiated keys */ + kuid_t uid; + int qnkeys; /* number of keys allocated to this user */ + int qnbytes; /* number of bytes allocated to this user */ +}; + +extern struct rb_root key_user_tree; +extern spinlock_t key_user_lock; +extern struct key_user root_key_user; + +extern struct key_user *key_user_lookup(kuid_t uid); +extern void key_user_put(struct key_user *user); + +/* + * Key quota limits. + * - root has its own separate limits to everyone else + */ +extern unsigned key_quota_root_maxkeys; +extern unsigned key_quota_root_maxbytes; +extern unsigned key_quota_maxkeys; +extern unsigned key_quota_maxbytes; + +#define KEYQUOTA_LINK_BYTES 4 /* a link in a keyring is worth 4 bytes */ + + +extern struct kmem_cache *key_jar; +extern struct rb_root key_serial_tree; +extern spinlock_t key_serial_lock; +extern struct mutex key_construction_mutex; +extern wait_queue_head_t request_key_conswq; + + +extern struct key_type *key_type_lookup(const char *type); +extern void key_type_put(struct key_type *ktype); + +extern int __key_link_begin(struct key *keyring, + const struct keyring_index_key *index_key, + struct assoc_array_edit **_edit); +extern int __key_link_check_live_key(struct key *keyring, struct key *key); +extern void __key_link(struct key *key, struct assoc_array_edit **_edit); +extern void __key_link_end(struct key *keyring, + const struct keyring_index_key *index_key, + struct assoc_array_edit *edit); + +extern key_ref_t find_key_to_update(key_ref_t keyring_ref, + const struct keyring_index_key *index_key); + +extern struct key *keyring_search_instkey(struct key *keyring, + key_serial_t target_id); + +extern int iterate_over_keyring(const struct key *keyring, + int (*func)(const struct key *key, void *data), + void *data); + +struct keyring_search_context { + struct keyring_index_key index_key; + const struct cred *cred; + struct key_match_data match_data; + unsigned flags; +#define KEYRING_SEARCH_NO_STATE_CHECK 0x0001 /* Skip state checks */ +#define KEYRING_SEARCH_DO_STATE_CHECK 0x0002 /* Override NO_STATE_CHECK */ +#define KEYRING_SEARCH_NO_UPDATE_TIME 0x0004 /* Don't update times */ +#define KEYRING_SEARCH_NO_CHECK_PERM 0x0008 /* Don't check permissions */ +#define KEYRING_SEARCH_DETECT_TOO_DEEP 0x0010 /* Give an error on excessive depth */ +#define KEYRING_SEARCH_SKIP_EXPIRED 0x0020 /* Ignore expired keys (intention to replace) */ + + int (*iterator)(const void *object, void *iterator_data); + + /* Internal stuff */ + int skipped_ret; + bool possessed; + key_ref_t result; + time64_t now; +}; + +extern bool key_default_cmp(const struct key *key, + const struct key_match_data *match_data); +extern key_ref_t keyring_search_aux(key_ref_t keyring_ref, + struct keyring_search_context *ctx); + +extern key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx); +extern key_ref_t search_process_keyrings(struct keyring_search_context *ctx); + +extern struct key *find_keyring_by_name(const char *name, bool uid_keyring); + +extern int install_user_keyrings(void); +extern int install_thread_keyring_to_cred(struct cred *); +extern int install_process_keyring_to_cred(struct cred *); +extern int install_session_keyring_to_cred(struct cred *, struct key *); + +extern struct key *request_key_and_link(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len, + void *aux, + struct key *dest_keyring, + unsigned long flags); + +extern bool lookup_user_key_possessed(const struct key *key, + const struct key_match_data *match_data); +extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags, + key_perm_t perm); +#define KEY_LOOKUP_CREATE 0x01 +#define KEY_LOOKUP_PARTIAL 0x02 +#define KEY_LOOKUP_FOR_UNLINK 0x04 + +extern long join_session_keyring(const char *name); +extern void key_change_session_keyring(struct callback_head *twork); + +extern struct work_struct key_gc_work; +extern unsigned key_gc_delay; +extern void keyring_gc(struct key *keyring, time64_t limit); +extern void keyring_restriction_gc(struct key *keyring, + struct key_type *dead_type); +extern void key_schedule_gc(time64_t gc_at); +extern void key_schedule_gc_links(void); +extern void key_gc_keytype(struct key_type *ktype); + +extern int key_task_permission(const key_ref_t key_ref, + const struct cred *cred, + key_perm_t perm); + +/* + * Check to see whether permission is granted to use a key in the desired way. + */ +static inline int key_permission(const key_ref_t key_ref, unsigned perm) +{ + return key_task_permission(key_ref, current_cred(), perm); +} + +extern struct key_type key_type_request_key_auth; +extern struct key *request_key_auth_new(struct key *target, + const char *op, + const void *callout_info, + size_t callout_len, + struct key *dest_keyring); + +extern struct key *key_get_instantiation_authkey(key_serial_t target_id); + +/* + * Determine whether a key is dead. + */ +static inline bool key_is_dead(const struct key *key, time64_t limit) +{ + return + key->flags & ((1 << KEY_FLAG_DEAD) | + (1 << KEY_FLAG_INVALIDATED)) || + (key->expiry > 0 && key->expiry <= limit); +} + +/* + * keyctl() functions + */ +extern long keyctl_get_keyring_ID(key_serial_t, int); +extern long keyctl_join_session_keyring(const char __user *); +extern long keyctl_update_key(key_serial_t, const void __user *, size_t); +extern long keyctl_revoke_key(key_serial_t); +extern long keyctl_keyring_clear(key_serial_t); +extern long keyctl_keyring_link(key_serial_t, key_serial_t); +extern long keyctl_keyring_unlink(key_serial_t, key_serial_t); +extern long keyctl_describe_key(key_serial_t, char __user *, size_t); +extern long keyctl_keyring_search(key_serial_t, const char __user *, + const char __user *, key_serial_t); +extern long keyctl_read_key(key_serial_t, char __user *, size_t); +extern long keyctl_chown_key(key_serial_t, uid_t, gid_t); +extern long keyctl_setperm_key(key_serial_t, key_perm_t); +extern long keyctl_instantiate_key(key_serial_t, const void __user *, + size_t, key_serial_t); +extern long keyctl_negate_key(key_serial_t, unsigned, key_serial_t); +extern long keyctl_set_reqkey_keyring(int); +extern long keyctl_set_timeout(key_serial_t, unsigned); +extern long keyctl_assume_authority(key_serial_t); +extern long keyctl_get_security(key_serial_t keyid, char __user *buffer, + size_t buflen); +extern long keyctl_session_to_parent(void); +extern long keyctl_reject_key(key_serial_t, unsigned, unsigned, key_serial_t); +extern long keyctl_instantiate_key_iov(key_serial_t, + const struct iovec __user *, + unsigned, key_serial_t); +extern long keyctl_invalidate_key(key_serial_t); + +struct iov_iter; +extern long keyctl_instantiate_key_common(key_serial_t, + struct iov_iter *, + key_serial_t); +extern long keyctl_restrict_keyring(key_serial_t id, + const char __user *_type, + const char __user *_restriction); +#ifdef CONFIG_PERSISTENT_KEYRINGS +extern long keyctl_get_persistent(uid_t, key_serial_t); +extern unsigned persistent_keyring_expiry; +#else +static inline long keyctl_get_persistent(uid_t uid, key_serial_t destring) +{ + return -EOPNOTSUPP; +} +#endif + +#ifdef CONFIG_KEY_DH_OPERATIONS +extern long keyctl_dh_compute(struct keyctl_dh_params __user *, char __user *, + size_t, struct keyctl_kdf_params __user *); +extern long __keyctl_dh_compute(struct keyctl_dh_params __user *, char __user *, + size_t, struct keyctl_kdf_params *); +#ifdef CONFIG_KEYS_COMPAT +extern long compat_keyctl_dh_compute(struct keyctl_dh_params __user *params, + char __user *buffer, size_t buflen, + struct compat_keyctl_kdf_params __user *kdf); +#endif +#define KEYCTL_KDF_MAX_OUTPUT_LEN 1024 /* max length of KDF output */ +#define KEYCTL_KDF_MAX_OI_LEN 64 /* max length of otherinfo */ +#else +static inline long keyctl_dh_compute(struct keyctl_dh_params __user *params, + char __user *buffer, size_t buflen, + struct keyctl_kdf_params __user *kdf) +{ + return -EOPNOTSUPP; +} + +#ifdef CONFIG_KEYS_COMPAT +static inline long compat_keyctl_dh_compute( + struct keyctl_dh_params __user *params, + char __user *buffer, size_t buflen, + struct keyctl_kdf_params __user *kdf) +{ + return -EOPNOTSUPP; +} +#endif +#endif + +/* + * Debugging key validation + */ +#ifdef KEY_DEBUGGING +extern void __key_check(const struct key *); + +static inline void key_check(const struct key *key) +{ + if (key && (IS_ERR(key) || key->magic != KEY_DEBUG_MAGIC)) + __key_check(key); +} + +#else + +#define key_check(key) do {} while(0) + +#endif +#endif /* _INTERNAL_H */ diff --git a/security/keys/key.c b/security/keys/key.c new file mode 100644 index 000000000..d3ebc0533 --- /dev/null +++ b/security/keys/key.c @@ -0,0 +1,1184 @@ +/* Basic authentication token and access key management + * + * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/poison.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/security.h> +#include <linux/workqueue.h> +#include <linux/random.h> +#include <linux/err.h> +#include "internal.h" + +struct kmem_cache *key_jar; +struct rb_root key_serial_tree; /* tree of keys indexed by serial */ +DEFINE_SPINLOCK(key_serial_lock); + +struct rb_root key_user_tree; /* tree of quota records indexed by UID */ +DEFINE_SPINLOCK(key_user_lock); + +unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */ +unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */ +unsigned int key_quota_maxkeys = 200; /* general key count quota */ +unsigned int key_quota_maxbytes = 20000; /* general key space quota */ + +static LIST_HEAD(key_types_list); +static DECLARE_RWSEM(key_types_sem); + +/* We serialise key instantiation and link */ +DEFINE_MUTEX(key_construction_mutex); + +#ifdef KEY_DEBUGGING +void __key_check(const struct key *key) +{ + printk("__key_check: key %p {%08x} should be {%08x}\n", + key, key->magic, KEY_DEBUG_MAGIC); + BUG(); +} +#endif + +/* + * Get the key quota record for a user, allocating a new record if one doesn't + * already exist. + */ +struct key_user *key_user_lookup(kuid_t uid) +{ + struct key_user *candidate = NULL, *user; + struct rb_node *parent, **p; + +try_again: + parent = NULL; + p = &key_user_tree.rb_node; + spin_lock(&key_user_lock); + + /* search the tree for a user record with a matching UID */ + while (*p) { + parent = *p; + user = rb_entry(parent, struct key_user, node); + + if (uid_lt(uid, user->uid)) + p = &(*p)->rb_left; + else if (uid_gt(uid, user->uid)) + p = &(*p)->rb_right; + else + goto found; + } + + /* if we get here, we failed to find a match in the tree */ + if (!candidate) { + /* allocate a candidate user record if we don't already have + * one */ + spin_unlock(&key_user_lock); + + user = NULL; + candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); + if (unlikely(!candidate)) + goto out; + + /* the allocation may have scheduled, so we need to repeat the + * search lest someone else added the record whilst we were + * asleep */ + goto try_again; + } + + /* if we get here, then the user record still hadn't appeared on the + * second pass - so we use the candidate record */ + refcount_set(&candidate->usage, 1); + atomic_set(&candidate->nkeys, 0); + atomic_set(&candidate->nikeys, 0); + candidate->uid = uid; + candidate->qnkeys = 0; + candidate->qnbytes = 0; + spin_lock_init(&candidate->lock); + mutex_init(&candidate->cons_lock); + + rb_link_node(&candidate->node, parent, p); + rb_insert_color(&candidate->node, &key_user_tree); + spin_unlock(&key_user_lock); + user = candidate; + goto out; + + /* okay - we found a user record for this UID */ +found: + refcount_inc(&user->usage); + spin_unlock(&key_user_lock); + kfree(candidate); +out: + return user; +} + +/* + * Dispose of a user structure + */ +void key_user_put(struct key_user *user) +{ + if (refcount_dec_and_lock(&user->usage, &key_user_lock)) { + rb_erase(&user->node, &key_user_tree); + spin_unlock(&key_user_lock); + + kfree(user); + } +} + +/* + * Allocate a serial number for a key. These are assigned randomly to avoid + * security issues through covert channel problems. + */ +static inline void key_alloc_serial(struct key *key) +{ + struct rb_node *parent, **p; + struct key *xkey; + + /* propose a random serial number and look for a hole for it in the + * serial number tree */ + do { + get_random_bytes(&key->serial, sizeof(key->serial)); + + key->serial >>= 1; /* negative numbers are not permitted */ + } while (key->serial < 3); + + spin_lock(&key_serial_lock); + +attempt_insertion: + parent = NULL; + p = &key_serial_tree.rb_node; + + while (*p) { + parent = *p; + xkey = rb_entry(parent, struct key, serial_node); + + if (key->serial < xkey->serial) + p = &(*p)->rb_left; + else if (key->serial > xkey->serial) + p = &(*p)->rb_right; + else + goto serial_exists; + } + + /* we've found a suitable hole - arrange for this key to occupy it */ + rb_link_node(&key->serial_node, parent, p); + rb_insert_color(&key->serial_node, &key_serial_tree); + + spin_unlock(&key_serial_lock); + return; + + /* we found a key with the proposed serial number - walk the tree from + * that point looking for the next unused serial number */ +serial_exists: + for (;;) { + key->serial++; + if (key->serial < 3) { + key->serial = 3; + goto attempt_insertion; + } + + parent = rb_next(parent); + if (!parent) + goto attempt_insertion; + + xkey = rb_entry(parent, struct key, serial_node); + if (key->serial < xkey->serial) + goto attempt_insertion; + } +} + +/** + * key_alloc - Allocate a key of the specified type. + * @type: The type of key to allocate. + * @desc: The key description to allow the key to be searched out. + * @uid: The owner of the new key. + * @gid: The group ID for the new key's group permissions. + * @cred: The credentials specifying UID namespace. + * @perm: The permissions mask of the new key. + * @flags: Flags specifying quota properties. + * @restrict_link: Optional link restriction for new keyrings. + * + * Allocate a key of the specified type with the attributes given. The key is + * returned in an uninstantiated state and the caller needs to instantiate the + * key before returning. + * + * The restrict_link structure (if not NULL) will be freed when the + * keyring is destroyed, so it must be dynamically allocated. + * + * The user's key count quota is updated to reflect the creation of the key and + * the user's key data quota has the default for the key type reserved. The + * instantiation function should amend this as necessary. If insufficient + * quota is available, -EDQUOT will be returned. + * + * The LSM security modules can prevent a key being created, in which case + * -EACCES will be returned. + * + * Returns a pointer to the new key if successful and an error code otherwise. + * + * Note that the caller needs to ensure the key type isn't uninstantiated. + * Internally this can be done by locking key_types_sem. Externally, this can + * be done by either never unregistering the key type, or making sure + * key_alloc() calls don't race with module unloading. + */ +struct key *key_alloc(struct key_type *type, const char *desc, + kuid_t uid, kgid_t gid, const struct cred *cred, + key_perm_t perm, unsigned long flags, + struct key_restriction *restrict_link) +{ + struct key_user *user = NULL; + struct key *key; + size_t desclen, quotalen; + int ret; + + key = ERR_PTR(-EINVAL); + if (!desc || !*desc) + goto error; + + if (type->vet_description) { + ret = type->vet_description(desc); + if (ret < 0) { + key = ERR_PTR(ret); + goto error; + } + } + + desclen = strlen(desc); + quotalen = desclen + 1 + type->def_datalen; + + /* get hold of the key tracking for this user */ + user = key_user_lookup(uid); + if (!user) + goto no_memory_1; + + /* check that the user's quota permits allocation of another key and + * its description */ + if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { + unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxkeys : key_quota_maxkeys; + unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxbytes : key_quota_maxbytes; + + spin_lock(&user->lock); + if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { + if (user->qnkeys + 1 > maxkeys || + user->qnbytes + quotalen > maxbytes || + user->qnbytes + quotalen < user->qnbytes) + goto no_quota; + } + + user->qnkeys++; + user->qnbytes += quotalen; + spin_unlock(&user->lock); + } + + /* allocate and initialise the key and its description */ + key = kmem_cache_zalloc(key_jar, GFP_KERNEL); + if (!key) + goto no_memory_2; + + key->index_key.desc_len = desclen; + key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL); + if (!key->index_key.description) + goto no_memory_3; + + refcount_set(&key->usage, 1); + init_rwsem(&key->sem); + lockdep_set_class(&key->sem, &type->lock_class); + key->index_key.type = type; + key->user = user; + key->quotalen = quotalen; + key->datalen = type->def_datalen; + key->uid = uid; + key->gid = gid; + key->perm = perm; + key->restrict_link = restrict_link; + key->last_used_at = ktime_get_real_seconds(); + + if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) + key->flags |= 1 << KEY_FLAG_IN_QUOTA; + if (flags & KEY_ALLOC_BUILT_IN) + key->flags |= 1 << KEY_FLAG_BUILTIN; + if (flags & KEY_ALLOC_UID_KEYRING) + key->flags |= 1 << KEY_FLAG_UID_KEYRING; + if (flags & KEY_ALLOC_SET_KEEP) + key->flags |= 1 << KEY_FLAG_KEEP; + +#ifdef KEY_DEBUGGING + key->magic = KEY_DEBUG_MAGIC; +#endif + + /* let the security module know about the key */ + ret = security_key_alloc(key, cred, flags); + if (ret < 0) + goto security_error; + + /* publish the key by giving it a serial number */ + atomic_inc(&user->nkeys); + key_alloc_serial(key); + +error: + return key; + +security_error: + kfree(key->description); + kmem_cache_free(key_jar, key); + if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { + spin_lock(&user->lock); + user->qnkeys--; + user->qnbytes -= quotalen; + spin_unlock(&user->lock); + } + key_user_put(user); + key = ERR_PTR(ret); + goto error; + +no_memory_3: + kmem_cache_free(key_jar, key); +no_memory_2: + if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { + spin_lock(&user->lock); + user->qnkeys--; + user->qnbytes -= quotalen; + spin_unlock(&user->lock); + } + key_user_put(user); +no_memory_1: + key = ERR_PTR(-ENOMEM); + goto error; + +no_quota: + spin_unlock(&user->lock); + key_user_put(user); + key = ERR_PTR(-EDQUOT); + goto error; +} +EXPORT_SYMBOL(key_alloc); + +/** + * key_payload_reserve - Adjust data quota reservation for the key's payload + * @key: The key to make the reservation for. + * @datalen: The amount of data payload the caller now wants. + * + * Adjust the amount of the owning user's key data quota that a key reserves. + * If the amount is increased, then -EDQUOT may be returned if there isn't + * enough free quota available. + * + * If successful, 0 is returned. + */ +int key_payload_reserve(struct key *key, size_t datalen) +{ + int delta = (int)datalen - key->datalen; + int ret = 0; + + key_check(key); + + /* contemplate the quota adjustment */ + if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { + unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxbytes : key_quota_maxbytes; + + spin_lock(&key->user->lock); + + if (delta > 0 && + (key->user->qnbytes + delta > maxbytes || + key->user->qnbytes + delta < key->user->qnbytes)) { + ret = -EDQUOT; + } + else { + key->user->qnbytes += delta; + key->quotalen += delta; + } + spin_unlock(&key->user->lock); + } + + /* change the recorded data length if that didn't generate an error */ + if (ret == 0) + key->datalen = datalen; + + return ret; +} +EXPORT_SYMBOL(key_payload_reserve); + +/* + * Change the key state to being instantiated. + */ +static void mark_key_instantiated(struct key *key, int reject_error) +{ + /* Commit the payload before setting the state; barrier versus + * key_read_state(). + */ + smp_store_release(&key->state, + (reject_error < 0) ? reject_error : KEY_IS_POSITIVE); +} + +/* + * Instantiate a key and link it into the target keyring atomically. Must be + * called with the target keyring's semaphore writelocked. The target key's + * semaphore need not be locked as instantiation is serialised by + * key_construction_mutex. + */ +static int __key_instantiate_and_link(struct key *key, + struct key_preparsed_payload *prep, + struct key *keyring, + struct key *authkey, + struct assoc_array_edit **_edit) +{ + int ret, awaken; + + key_check(key); + key_check(keyring); + + awaken = 0; + ret = -EBUSY; + + mutex_lock(&key_construction_mutex); + + /* can't instantiate twice */ + if (key->state == KEY_IS_UNINSTANTIATED) { + /* instantiate the key */ + ret = key->type->instantiate(key, prep); + + if (ret == 0) { + /* mark the key as being instantiated */ + atomic_inc(&key->user->nikeys); + mark_key_instantiated(key, 0); + + if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) + awaken = 1; + + /* and link it into the destination keyring */ + if (keyring) { + if (test_bit(KEY_FLAG_KEEP, &keyring->flags)) + set_bit(KEY_FLAG_KEEP, &key->flags); + + __key_link(key, _edit); + } + + /* disable the authorisation key */ + if (authkey) + key_revoke(authkey); + + if (prep->expiry != TIME64_MAX) { + key->expiry = prep->expiry; + key_schedule_gc(prep->expiry + key_gc_delay); + } + } + } + + mutex_unlock(&key_construction_mutex); + + /* wake up anyone waiting for a key to be constructed */ + if (awaken) + wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); + + return ret; +} + +/** + * key_instantiate_and_link - Instantiate a key and link it into the keyring. + * @key: The key to instantiate. + * @data: The data to use to instantiate the keyring. + * @datalen: The length of @data. + * @keyring: Keyring to create a link in on success (or NULL). + * @authkey: The authorisation token permitting instantiation. + * + * Instantiate a key that's in the uninstantiated state using the provided data + * and, if successful, link it in to the destination keyring if one is + * supplied. + * + * If successful, 0 is returned, the authorisation token is revoked and anyone + * waiting for the key is woken up. If the key was already instantiated, + * -EBUSY will be returned. + */ +int key_instantiate_and_link(struct key *key, + const void *data, + size_t datalen, + struct key *keyring, + struct key *authkey) +{ + struct key_preparsed_payload prep; + struct assoc_array_edit *edit; + int ret; + + memset(&prep, 0, sizeof(prep)); + prep.data = data; + prep.datalen = datalen; + prep.quotalen = key->type->def_datalen; + prep.expiry = TIME64_MAX; + if (key->type->preparse) { + ret = key->type->preparse(&prep); + if (ret < 0) + goto error; + } + + if (keyring) { + ret = __key_link_begin(keyring, &key->index_key, &edit); + if (ret < 0) + goto error; + + if (keyring->restrict_link && keyring->restrict_link->check) { + struct key_restriction *keyres = keyring->restrict_link; + + ret = keyres->check(keyring, key->type, &prep.payload, + keyres->key); + if (ret < 0) + goto error_link_end; + } + } + + ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit); + +error_link_end: + if (keyring) + __key_link_end(keyring, &key->index_key, edit); + +error: + if (key->type->preparse) + key->type->free_preparse(&prep); + return ret; +} + +EXPORT_SYMBOL(key_instantiate_and_link); + +/** + * key_reject_and_link - Negatively instantiate a key and link it into the keyring. + * @key: The key to instantiate. + * @timeout: The timeout on the negative key. + * @error: The error to return when the key is hit. + * @keyring: Keyring to create a link in on success (or NULL). + * @authkey: The authorisation token permitting instantiation. + * + * Negatively instantiate a key that's in the uninstantiated state and, if + * successful, set its timeout and stored error and link it in to the + * destination keyring if one is supplied. The key and any links to the key + * will be automatically garbage collected after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return the stored error code (typically ENOKEY) until the negative + * key expires. + * + * If successful, 0 is returned, the authorisation token is revoked and anyone + * waiting for the key is woken up. If the key was already instantiated, + * -EBUSY will be returned. + */ +int key_reject_and_link(struct key *key, + unsigned timeout, + unsigned error, + struct key *keyring, + struct key *authkey) +{ + struct assoc_array_edit *edit; + int ret, awaken, link_ret = 0; + + key_check(key); + key_check(keyring); + + awaken = 0; + ret = -EBUSY; + + if (keyring) { + if (keyring->restrict_link) + return -EPERM; + + link_ret = __key_link_begin(keyring, &key->index_key, &edit); + } + + mutex_lock(&key_construction_mutex); + + /* can't instantiate twice */ + if (key->state == KEY_IS_UNINSTANTIATED) { + /* mark the key as being negatively instantiated */ + atomic_inc(&key->user->nikeys); + mark_key_instantiated(key, -error); + key->expiry = ktime_get_real_seconds() + timeout; + key_schedule_gc(key->expiry + key_gc_delay); + + if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) + awaken = 1; + + ret = 0; + + /* and link it into the destination keyring */ + if (keyring && link_ret == 0) + __key_link(key, &edit); + + /* disable the authorisation key */ + if (authkey) + key_revoke(authkey); + } + + mutex_unlock(&key_construction_mutex); + + if (keyring && link_ret == 0) + __key_link_end(keyring, &key->index_key, edit); + + /* wake up anyone waiting for a key to be constructed */ + if (awaken) + wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); + + return ret == 0 ? link_ret : ret; +} +EXPORT_SYMBOL(key_reject_and_link); + +/** + * key_put - Discard a reference to a key. + * @key: The key to discard a reference from. + * + * Discard a reference to a key, and when all the references are gone, we + * schedule the cleanup task to come and pull it out of the tree in process + * context at some later time. + */ +void key_put(struct key *key) +{ + if (key) { + key_check(key); + + if (refcount_dec_and_test(&key->usage)) + schedule_work(&key_gc_work); + } +} +EXPORT_SYMBOL(key_put); + +/* + * Find a key by its serial number. + */ +struct key *key_lookup(key_serial_t id) +{ + struct rb_node *n; + struct key *key; + + spin_lock(&key_serial_lock); + + /* search the tree for the specified key */ + n = key_serial_tree.rb_node; + while (n) { + key = rb_entry(n, struct key, serial_node); + + if (id < key->serial) + n = n->rb_left; + else if (id > key->serial) + n = n->rb_right; + else + goto found; + } + +not_found: + key = ERR_PTR(-ENOKEY); + goto error; + +found: + /* A key is allowed to be looked up only if someone still owns a + * reference to it - otherwise it's awaiting the gc. + */ + if (!refcount_inc_not_zero(&key->usage)) + goto not_found; + +error: + spin_unlock(&key_serial_lock); + return key; +} + +/* + * Find and lock the specified key type against removal. + * + * We return with the sem read-locked if successful. If the type wasn't + * available -ENOKEY is returned instead. + */ +struct key_type *key_type_lookup(const char *type) +{ + struct key_type *ktype; + + down_read(&key_types_sem); + + /* look up the key type to see if it's one of the registered kernel + * types */ + list_for_each_entry(ktype, &key_types_list, link) { + if (strcmp(ktype->name, type) == 0) + goto found_kernel_type; + } + + up_read(&key_types_sem); + ktype = ERR_PTR(-ENOKEY); + +found_kernel_type: + return ktype; +} + +void key_set_timeout(struct key *key, unsigned timeout) +{ + time64_t expiry = 0; + + /* make the changes with the locks held to prevent races */ + down_write(&key->sem); + + if (timeout > 0) + expiry = ktime_get_real_seconds() + timeout; + + key->expiry = expiry; + key_schedule_gc(key->expiry + key_gc_delay); + + up_write(&key->sem); +} +EXPORT_SYMBOL_GPL(key_set_timeout); + +/* + * Unlock a key type locked by key_type_lookup(). + */ +void key_type_put(struct key_type *ktype) +{ + up_read(&key_types_sem); +} + +/* + * Attempt to update an existing key. + * + * The key is given to us with an incremented refcount that we need to discard + * if we get an error. + */ +static inline key_ref_t __key_update(key_ref_t key_ref, + struct key_preparsed_payload *prep) +{ + struct key *key = key_ref_to_ptr(key_ref); + int ret; + + /* need write permission on the key to update it */ + ret = key_permission(key_ref, KEY_NEED_WRITE); + if (ret < 0) + goto error; + + ret = -EEXIST; + if (!key->type->update) + goto error; + + down_write(&key->sem); + + ret = key->type->update(key, prep); + if (ret == 0) + /* Updating a negative key positively instantiates it */ + mark_key_instantiated(key, 0); + + up_write(&key->sem); + + if (ret < 0) + goto error; +out: + return key_ref; + +error: + key_put(key); + key_ref = ERR_PTR(ret); + goto out; +} + +/** + * key_create_or_update - Update or create and instantiate a key. + * @keyring_ref: A pointer to the destination keyring with possession flag. + * @type: The type of key. + * @description: The searchable description for the key. + * @payload: The data to use to instantiate or update the key. + * @plen: The length of @payload. + * @perm: The permissions mask for a new key. + * @flags: The quota flags for a new key. + * + * Search the destination keyring for a key of the same description and if one + * is found, update it, otherwise create and instantiate a new one and create a + * link to it from that keyring. + * + * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be + * concocted. + * + * Returns a pointer to the new key if successful, -ENODEV if the key type + * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the + * caller isn't permitted to modify the keyring or the LSM did not permit + * creation of the key. + * + * On success, the possession flag from the keyring ref will be tacked on to + * the key ref before it is returned. + */ +key_ref_t key_create_or_update(key_ref_t keyring_ref, + const char *type, + const char *description, + const void *payload, + size_t plen, + key_perm_t perm, + unsigned long flags) +{ + struct keyring_index_key index_key = { + .description = description, + }; + struct key_preparsed_payload prep; + struct assoc_array_edit *edit; + const struct cred *cred = current_cred(); + struct key *keyring, *key = NULL; + key_ref_t key_ref; + int ret; + struct key_restriction *restrict_link = NULL; + + /* look up the key type to see if it's one of the registered kernel + * types */ + index_key.type = key_type_lookup(type); + if (IS_ERR(index_key.type)) { + key_ref = ERR_PTR(-ENODEV); + goto error; + } + + key_ref = ERR_PTR(-EINVAL); + if (!index_key.type->instantiate || + (!index_key.description && !index_key.type->preparse)) + goto error_put_type; + + keyring = key_ref_to_ptr(keyring_ref); + + key_check(keyring); + + if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION)) + restrict_link = keyring->restrict_link; + + key_ref = ERR_PTR(-ENOTDIR); + if (keyring->type != &key_type_keyring) + goto error_put_type; + + memset(&prep, 0, sizeof(prep)); + prep.data = payload; + prep.datalen = plen; + prep.quotalen = index_key.type->def_datalen; + prep.expiry = TIME64_MAX; + if (index_key.type->preparse) { + ret = index_key.type->preparse(&prep); + if (ret < 0) { + key_ref = ERR_PTR(ret); + goto error_free_prep; + } + if (!index_key.description) + index_key.description = prep.description; + key_ref = ERR_PTR(-EINVAL); + if (!index_key.description) + goto error_free_prep; + } + index_key.desc_len = strlen(index_key.description); + + ret = __key_link_begin(keyring, &index_key, &edit); + if (ret < 0) { + key_ref = ERR_PTR(ret); + goto error_free_prep; + } + + if (restrict_link && restrict_link->check) { + ret = restrict_link->check(keyring, index_key.type, + &prep.payload, restrict_link->key); + if (ret < 0) { + key_ref = ERR_PTR(ret); + goto error_link_end; + } + } + + /* if we're going to allocate a new key, we're going to have + * to modify the keyring */ + ret = key_permission(keyring_ref, KEY_NEED_WRITE); + if (ret < 0) { + key_ref = ERR_PTR(ret); + goto error_link_end; + } + + /* if it's possible to update this type of key, search for an existing + * key of the same type and description in the destination keyring and + * update that instead if possible + */ + if (index_key.type->update) { + key_ref = find_key_to_update(keyring_ref, &index_key); + if (key_ref) + goto found_matching_key; + } + + /* if the client doesn't provide, decide on the permissions we want */ + if (perm == KEY_PERM_UNDEF) { + perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; + perm |= KEY_USR_VIEW; + + if (index_key.type->read) + perm |= KEY_POS_READ; + + if (index_key.type == &key_type_keyring || + index_key.type->update) + perm |= KEY_POS_WRITE; + } + + /* allocate a new key */ + key = key_alloc(index_key.type, index_key.description, + cred->fsuid, cred->fsgid, cred, perm, flags, NULL); + if (IS_ERR(key)) { + key_ref = ERR_CAST(key); + goto error_link_end; + } + + /* instantiate it and link it into the target keyring */ + ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit); + if (ret < 0) { + key_put(key); + key_ref = ERR_PTR(ret); + goto error_link_end; + } + + key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); + +error_link_end: + __key_link_end(keyring, &index_key, edit); +error_free_prep: + if (index_key.type->preparse) + index_key.type->free_preparse(&prep); +error_put_type: + key_type_put(index_key.type); +error: + return key_ref; + + found_matching_key: + /* we found a matching key, so we're going to try to update it + * - we can drop the locks first as we have the key pinned + */ + __key_link_end(keyring, &index_key, edit); + + key = key_ref_to_ptr(key_ref); + if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) { + ret = wait_for_key_construction(key, true); + if (ret < 0) { + key_ref_put(key_ref); + key_ref = ERR_PTR(ret); + goto error_free_prep; + } + } + + key_ref = __key_update(key_ref, &prep); + goto error_free_prep; +} +EXPORT_SYMBOL(key_create_or_update); + +/** + * key_update - Update a key's contents. + * @key_ref: The pointer (plus possession flag) to the key. + * @payload: The data to be used to update the key. + * @plen: The length of @payload. + * + * Attempt to update the contents of a key with the given payload data. The + * caller must be granted Write permission on the key. Negative keys can be + * instantiated by this method. + * + * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key + * type does not support updating. The key type may return other errors. + */ +int key_update(key_ref_t key_ref, const void *payload, size_t plen) +{ + struct key_preparsed_payload prep; + struct key *key = key_ref_to_ptr(key_ref); + int ret; + + key_check(key); + + /* the key must be writable */ + ret = key_permission(key_ref, KEY_NEED_WRITE); + if (ret < 0) + return ret; + + /* attempt to update it if supported */ + if (!key->type->update) + return -EOPNOTSUPP; + + memset(&prep, 0, sizeof(prep)); + prep.data = payload; + prep.datalen = plen; + prep.quotalen = key->type->def_datalen; + prep.expiry = TIME64_MAX; + if (key->type->preparse) { + ret = key->type->preparse(&prep); + if (ret < 0) + goto error; + } + + down_write(&key->sem); + + ret = key->type->update(key, &prep); + if (ret == 0) + /* Updating a negative key positively instantiates it */ + mark_key_instantiated(key, 0); + + up_write(&key->sem); + +error: + if (key->type->preparse) + key->type->free_preparse(&prep); + return ret; +} +EXPORT_SYMBOL(key_update); + +/** + * key_revoke - Revoke a key. + * @key: The key to be revoked. + * + * Mark a key as being revoked and ask the type to free up its resources. The + * revocation timeout is set and the key and all its links will be + * automatically garbage collected after key_gc_delay amount of time if they + * are not manually dealt with first. + */ +void key_revoke(struct key *key) +{ + time64_t time; + + key_check(key); + + /* make sure no one's trying to change or use the key when we mark it + * - we tell lockdep that we might nest because we might be revoking an + * authorisation key whilst holding the sem on a key we've just + * instantiated + */ + down_write_nested(&key->sem, 1); + if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) && + key->type->revoke) + key->type->revoke(key); + + /* set the death time to no more than the expiry time */ + time = ktime_get_real_seconds(); + if (key->revoked_at == 0 || key->revoked_at > time) { + key->revoked_at = time; + key_schedule_gc(key->revoked_at + key_gc_delay); + } + + up_write(&key->sem); +} +EXPORT_SYMBOL(key_revoke); + +/** + * key_invalidate - Invalidate a key. + * @key: The key to be invalidated. + * + * Mark a key as being invalidated and have it cleaned up immediately. The key + * is ignored by all searches and other operations from this point. + */ +void key_invalidate(struct key *key) +{ + kenter("%d", key_serial(key)); + + key_check(key); + + if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) { + down_write_nested(&key->sem, 1); + if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) + key_schedule_gc_links(); + up_write(&key->sem); + } +} +EXPORT_SYMBOL(key_invalidate); + +/** + * generic_key_instantiate - Simple instantiation of a key from preparsed data + * @key: The key to be instantiated + * @prep: The preparsed data to load. + * + * Instantiate a key from preparsed data. We assume we can just copy the data + * in directly and clear the old pointers. + * + * This can be pointed to directly by the key type instantiate op pointer. + */ +int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep) +{ + int ret; + + pr_devel("==>%s()\n", __func__); + + ret = key_payload_reserve(key, prep->quotalen); + if (ret == 0) { + rcu_assign_keypointer(key, prep->payload.data[0]); + key->payload.data[1] = prep->payload.data[1]; + key->payload.data[2] = prep->payload.data[2]; + key->payload.data[3] = prep->payload.data[3]; + prep->payload.data[0] = NULL; + prep->payload.data[1] = NULL; + prep->payload.data[2] = NULL; + prep->payload.data[3] = NULL; + } + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL(generic_key_instantiate); + +/** + * register_key_type - Register a type of key. + * @ktype: The new key type. + * + * Register a new key type. + * + * Returns 0 on success or -EEXIST if a type of this name already exists. + */ +int register_key_type(struct key_type *ktype) +{ + struct key_type *p; + int ret; + + memset(&ktype->lock_class, 0, sizeof(ktype->lock_class)); + + ret = -EEXIST; + down_write(&key_types_sem); + + /* disallow key types with the same name */ + list_for_each_entry(p, &key_types_list, link) { + if (strcmp(p->name, ktype->name) == 0) + goto out; + } + + /* store the type */ + list_add(&ktype->link, &key_types_list); + + pr_notice("Key type %s registered\n", ktype->name); + ret = 0; + +out: + up_write(&key_types_sem); + return ret; +} +EXPORT_SYMBOL(register_key_type); + +/** + * unregister_key_type - Unregister a type of key. + * @ktype: The key type. + * + * Unregister a key type and mark all the extant keys of this type as dead. + * Those keys of this type are then destroyed to get rid of their payloads and + * they and their links will be garbage collected as soon as possible. + */ +void unregister_key_type(struct key_type *ktype) +{ + down_write(&key_types_sem); + list_del_init(&ktype->link); + downgrade_write(&key_types_sem); + key_gc_keytype(ktype); + pr_notice("Key type %s unregistered\n", ktype->name); + up_read(&key_types_sem); +} +EXPORT_SYMBOL(unregister_key_type); + +/* + * Initialise the key management state. + */ +void __init key_init(void) +{ + /* allocate a slab in which we can store keys */ + key_jar = kmem_cache_create("key_jar", sizeof(struct key), + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); + + /* add the special key types */ + list_add_tail(&key_type_keyring.link, &key_types_list); + list_add_tail(&key_type_dead.link, &key_types_list); + list_add_tail(&key_type_user.link, &key_types_list); + list_add_tail(&key_type_logon.link, &key_types_list); + + /* record the root user tracking */ + rb_link_node(&root_key_user.node, + NULL, + &key_user_tree.rb_node); + + rb_insert_color(&root_key_user.node, + &key_user_tree); +} diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c new file mode 100644 index 000000000..9394d72a7 --- /dev/null +++ b/security/keys/keyctl.c @@ -0,0 +1,1817 @@ +/* Userspace key control operations + * + * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/sched/task.h> +#include <linux/slab.h> +#include <linux/syscalls.h> +#include <linux/key.h> +#include <linux/keyctl.h> +#include <linux/fs.h> +#include <linux/capability.h> +#include <linux/cred.h> +#include <linux/string.h> +#include <linux/err.h> +#include <linux/vmalloc.h> +#include <linux/security.h> +#include <linux/uio.h> +#include <linux/uaccess.h> +#include <keys/request_key_auth-type.h> +#include "internal.h" + +#define KEY_MAX_DESC_SIZE 4096 + +static int key_get_type_from_user(char *type, + const char __user *_type, + unsigned len) +{ + int ret; + + ret = strncpy_from_user(type, _type, len); + if (ret < 0) + return ret; + if (ret == 0 || ret >= len) + return -EINVAL; + if (type[0] == '.') + return -EPERM; + type[len - 1] = '\0'; + return 0; +} + +/* + * Extract the description of a new key from userspace and either add it as a + * new key to the specified keyring or update a matching key in that keyring. + * + * If the description is NULL or an empty string, the key type is asked to + * generate one from the payload. + * + * The keyring must be writable so that we can attach the key to it. + * + * If successful, the new key's serial number is returned, otherwise an error + * code is returned. + */ +SYSCALL_DEFINE5(add_key, const char __user *, _type, + const char __user *, _description, + const void __user *, _payload, + size_t, plen, + key_serial_t, ringid) +{ + key_ref_t keyring_ref, key_ref; + char type[32], *description; + void *payload; + long ret; + + ret = -EINVAL; + if (plen > 1024 * 1024 - 1) + goto error; + + /* draw all the data into kernel space */ + ret = key_get_type_from_user(type, _type, sizeof(type)); + if (ret < 0) + goto error; + + description = NULL; + if (_description) { + description = strndup_user(_description, KEY_MAX_DESC_SIZE); + if (IS_ERR(description)) { + ret = PTR_ERR(description); + goto error; + } + if (!*description) { + kfree(description); + description = NULL; + } else if ((description[0] == '.') && + (strncmp(type, "keyring", 7) == 0)) { + ret = -EPERM; + goto error2; + } + } + + /* pull the payload in if one was supplied */ + payload = NULL; + + if (plen) { + ret = -ENOMEM; + payload = kvmalloc(plen, GFP_KERNEL); + if (!payload) + goto error2; + + ret = -EFAULT; + if (copy_from_user(payload, _payload, plen) != 0) + goto error3; + } + + /* find the target keyring (which must be writable) */ + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); + if (IS_ERR(keyring_ref)) { + ret = PTR_ERR(keyring_ref); + goto error3; + } + + /* create or update the requested key and add it to the target + * keyring */ + key_ref = key_create_or_update(keyring_ref, type, description, + payload, plen, KEY_PERM_UNDEF, + KEY_ALLOC_IN_QUOTA); + if (!IS_ERR(key_ref)) { + ret = key_ref_to_ptr(key_ref)->serial; + key_ref_put(key_ref); + } + else { + ret = PTR_ERR(key_ref); + } + + key_ref_put(keyring_ref); + error3: + kvfree_sensitive(payload, plen); + error2: + kfree(description); + error: + return ret; +} + +/* + * Search the process keyrings and keyring trees linked from those for a + * matching key. Keyrings must have appropriate Search permission to be + * searched. + * + * If a key is found, it will be attached to the destination keyring if there's + * one specified and the serial number of the key will be returned. + * + * If no key is found, /sbin/request-key will be invoked if _callout_info is + * non-NULL in an attempt to create a key. The _callout_info string will be + * passed to /sbin/request-key to aid with completing the request. If the + * _callout_info string is "" then it will be changed to "-". + */ +SYSCALL_DEFINE4(request_key, const char __user *, _type, + const char __user *, _description, + const char __user *, _callout_info, + key_serial_t, destringid) +{ + struct key_type *ktype; + struct key *key; + key_ref_t dest_ref; + size_t callout_len; + char type[32], *description, *callout_info; + long ret; + + /* pull the type into kernel space */ + ret = key_get_type_from_user(type, _type, sizeof(type)); + if (ret < 0) + goto error; + + /* pull the description into kernel space */ + description = strndup_user(_description, KEY_MAX_DESC_SIZE); + if (IS_ERR(description)) { + ret = PTR_ERR(description); + goto error; + } + + /* pull the callout info into kernel space */ + callout_info = NULL; + callout_len = 0; + if (_callout_info) { + callout_info = strndup_user(_callout_info, PAGE_SIZE); + if (IS_ERR(callout_info)) { + ret = PTR_ERR(callout_info); + goto error2; + } + callout_len = strlen(callout_info); + } + + /* get the destination keyring if specified */ + dest_ref = NULL; + if (destringid) { + dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, + KEY_NEED_WRITE); + if (IS_ERR(dest_ref)) { + ret = PTR_ERR(dest_ref); + goto error3; + } + } + + /* find the key type */ + ktype = key_type_lookup(type); + if (IS_ERR(ktype)) { + ret = PTR_ERR(ktype); + goto error4; + } + + /* do the search */ + key = request_key_and_link(ktype, description, callout_info, + callout_len, NULL, key_ref_to_ptr(dest_ref), + KEY_ALLOC_IN_QUOTA); + if (IS_ERR(key)) { + ret = PTR_ERR(key); + goto error5; + } + + /* wait for the key to finish being constructed */ + ret = wait_for_key_construction(key, 1); + if (ret < 0) + goto error6; + + ret = key->serial; + +error6: + key_put(key); +error5: + key_type_put(ktype); +error4: + key_ref_put(dest_ref); +error3: + kfree(callout_info); +error2: + kfree(description); +error: + return ret; +} + +/* + * Get the ID of the specified process keyring. + * + * The requested keyring must have search permission to be found. + * + * If successful, the ID of the requested keyring will be returned. + */ +long keyctl_get_keyring_ID(key_serial_t id, int create) +{ + key_ref_t key_ref; + unsigned long lflags; + long ret; + + lflags = create ? KEY_LOOKUP_CREATE : 0; + key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error; + } + + ret = key_ref_to_ptr(key_ref)->serial; + key_ref_put(key_ref); +error: + return ret; +} + +/* + * Join a (named) session keyring. + * + * Create and join an anonymous session keyring or join a named session + * keyring, creating it if necessary. A named session keyring must have Search + * permission for it to be joined. Session keyrings without this permit will + * be skipped over. It is not permitted for userspace to create or join + * keyrings whose name begin with a dot. + * + * If successful, the ID of the joined session keyring will be returned. + */ +long keyctl_join_session_keyring(const char __user *_name) +{ + char *name; + long ret; + + /* fetch the name from userspace */ + name = NULL; + if (_name) { + name = strndup_user(_name, KEY_MAX_DESC_SIZE); + if (IS_ERR(name)) { + ret = PTR_ERR(name); + goto error; + } + + ret = -EPERM; + if (name[0] == '.') + goto error_name; + } + + /* join the session */ + ret = join_session_keyring(name); +error_name: + kfree(name); +error: + return ret; +} + +/* + * Update a key's data payload from the given data. + * + * The key must grant the caller Write permission and the key type must support + * updating for this to work. A negative key can be positively instantiated + * with this call. + * + * If successful, 0 will be returned. If the key type does not support + * updating, then -EOPNOTSUPP will be returned. + */ +long keyctl_update_key(key_serial_t id, + const void __user *_payload, + size_t plen) +{ + key_ref_t key_ref; + void *payload; + long ret; + + ret = -EINVAL; + if (plen > PAGE_SIZE) + goto error; + + /* pull the payload in if one was supplied */ + payload = NULL; + if (plen) { + ret = -ENOMEM; + payload = kvmalloc(plen, GFP_KERNEL); + if (!payload) + goto error; + + ret = -EFAULT; + if (copy_from_user(payload, _payload, plen) != 0) + goto error2; + } + + /* find the target key (which must be writable) */ + key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error2; + } + + /* update the key */ + ret = key_update(key_ref, payload, plen); + + key_ref_put(key_ref); +error2: + kvfree_sensitive(payload, plen); +error: + return ret; +} + +/* + * Revoke a key. + * + * The key must be grant the caller Write or Setattr permission for this to + * work. The key type should give up its quota claim when revoked. The key + * and any links to the key will be automatically garbage collected after a + * certain amount of time (/proc/sys/kernel/keys/gc_delay). + * + * Keys with KEY_FLAG_KEEP set should not be revoked. + * + * If successful, 0 is returned. + */ +long keyctl_revoke_key(key_serial_t id) +{ + key_ref_t key_ref; + struct key *key; + long ret; + + key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + if (ret != -EACCES) + goto error; + key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error; + } + } + + key = key_ref_to_ptr(key_ref); + ret = 0; + if (test_bit(KEY_FLAG_KEEP, &key->flags)) + ret = -EPERM; + else + key_revoke(key); + + key_ref_put(key_ref); +error: + return ret; +} + +/* + * Invalidate a key. + * + * The key must be grant the caller Invalidate permission for this to work. + * The key and any links to the key will be automatically garbage collected + * immediately. + * + * Keys with KEY_FLAG_KEEP set should not be invalidated. + * + * If successful, 0 is returned. + */ +long keyctl_invalidate_key(key_serial_t id) +{ + key_ref_t key_ref; + struct key *key; + long ret; + + kenter("%d", id); + + key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + + /* Root is permitted to invalidate certain special keys */ + if (capable(CAP_SYS_ADMIN)) { + key_ref = lookup_user_key(id, 0, 0); + if (IS_ERR(key_ref)) + goto error; + if (test_bit(KEY_FLAG_ROOT_CAN_INVAL, + &key_ref_to_ptr(key_ref)->flags)) + goto invalidate; + goto error_put; + } + + goto error; + } + +invalidate: + key = key_ref_to_ptr(key_ref); + ret = 0; + if (test_bit(KEY_FLAG_KEEP, &key->flags)) + ret = -EPERM; + else + key_invalidate(key); +error_put: + key_ref_put(key_ref); +error: + kleave(" = %ld", ret); + return ret; +} + +/* + * Clear the specified keyring, creating an empty process keyring if one of the + * special keyring IDs is used. + * + * The keyring must grant the caller Write permission and not have + * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned. + */ +long keyctl_keyring_clear(key_serial_t ringid) +{ + key_ref_t keyring_ref; + struct key *keyring; + long ret; + + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); + if (IS_ERR(keyring_ref)) { + ret = PTR_ERR(keyring_ref); + + /* Root is permitted to invalidate certain special keyrings */ + if (capable(CAP_SYS_ADMIN)) { + keyring_ref = lookup_user_key(ringid, 0, 0); + if (IS_ERR(keyring_ref)) + goto error; + if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR, + &key_ref_to_ptr(keyring_ref)->flags)) + goto clear; + goto error_put; + } + + goto error; + } + +clear: + keyring = key_ref_to_ptr(keyring_ref); + if (test_bit(KEY_FLAG_KEEP, &keyring->flags)) + ret = -EPERM; + else + ret = keyring_clear(keyring); +error_put: + key_ref_put(keyring_ref); +error: + return ret; +} + +/* + * Create a link from a keyring to a key if there's no matching key in the + * keyring, otherwise replace the link to the matching key with a link to the + * new key. + * + * The key must grant the caller Link permission and the the keyring must grant + * the caller Write permission. Furthermore, if an additional link is created, + * the keyring's quota will be extended. + * + * If successful, 0 will be returned. + */ +long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) +{ + key_ref_t keyring_ref, key_ref; + long ret; + + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); + if (IS_ERR(keyring_ref)) { + ret = PTR_ERR(keyring_ref); + goto error; + } + + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error2; + } + + ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); + + key_ref_put(key_ref); +error2: + key_ref_put(keyring_ref); +error: + return ret; +} + +/* + * Unlink a key from a keyring. + * + * The keyring must grant the caller Write permission for this to work; the key + * itself need not grant the caller anything. If the last link to a key is + * removed then that key will be scheduled for destruction. + * + * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked. + * + * If successful, 0 will be returned. + */ +long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) +{ + key_ref_t keyring_ref, key_ref; + struct key *keyring, *key; + long ret; + + keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE); + if (IS_ERR(keyring_ref)) { + ret = PTR_ERR(keyring_ref); + goto error; + } + + key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error2; + } + + keyring = key_ref_to_ptr(keyring_ref); + key = key_ref_to_ptr(key_ref); + if (test_bit(KEY_FLAG_KEEP, &keyring->flags) && + test_bit(KEY_FLAG_KEEP, &key->flags)) + ret = -EPERM; + else + ret = key_unlink(keyring, key); + + key_ref_put(key_ref); +error2: + key_ref_put(keyring_ref); +error: + return ret; +} + +/* + * Return a description of a key to userspace. + * + * The key must grant the caller View permission for this to work. + * + * If there's a buffer, we place up to buflen bytes of data into it formatted + * in the following way: + * + * type;uid;gid;perm;description<NUL> + * + * If successful, we return the amount of description available, irrespective + * of how much we may have copied into the buffer. + */ +long keyctl_describe_key(key_serial_t keyid, + char __user *buffer, + size_t buflen) +{ + struct key *key, *instkey; + key_ref_t key_ref; + char *infobuf; + long ret; + int desclen, infolen; + + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW); + if (IS_ERR(key_ref)) { + /* viewing a key under construction is permitted if we have the + * authorisation token handy */ + if (PTR_ERR(key_ref) == -EACCES) { + instkey = key_get_instantiation_authkey(keyid); + if (!IS_ERR(instkey)) { + key_put(instkey); + key_ref = lookup_user_key(keyid, + KEY_LOOKUP_PARTIAL, + 0); + if (!IS_ERR(key_ref)) + goto okay; + } + } + + ret = PTR_ERR(key_ref); + goto error; + } + +okay: + key = key_ref_to_ptr(key_ref); + desclen = strlen(key->description); + + /* calculate how much information we're going to return */ + ret = -ENOMEM; + infobuf = kasprintf(GFP_KERNEL, + "%s;%d;%d;%08x;", + key->type->name, + from_kuid_munged(current_user_ns(), key->uid), + from_kgid_munged(current_user_ns(), key->gid), + key->perm); + if (!infobuf) + goto error2; + infolen = strlen(infobuf); + ret = infolen + desclen + 1; + + /* consider returning the data */ + if (buffer && buflen >= ret) { + if (copy_to_user(buffer, infobuf, infolen) != 0 || + copy_to_user(buffer + infolen, key->description, + desclen + 1) != 0) + ret = -EFAULT; + } + + kfree(infobuf); +error2: + key_ref_put(key_ref); +error: + return ret; +} + +/* + * Search the specified keyring and any keyrings it links to for a matching + * key. Only keyrings that grant the caller Search permission will be searched + * (this includes the starting keyring). Only keys with Search permission can + * be found. + * + * If successful, the found key will be linked to the destination keyring if + * supplied and the key has Link permission, and the found key ID will be + * returned. + */ +long keyctl_keyring_search(key_serial_t ringid, + const char __user *_type, + const char __user *_description, + key_serial_t destringid) +{ + struct key_type *ktype; + key_ref_t keyring_ref, key_ref, dest_ref; + char type[32], *description; + long ret; + + /* pull the type and description into kernel space */ + ret = key_get_type_from_user(type, _type, sizeof(type)); + if (ret < 0) + goto error; + + description = strndup_user(_description, KEY_MAX_DESC_SIZE); + if (IS_ERR(description)) { + ret = PTR_ERR(description); + goto error; + } + + /* get the keyring at which to begin the search */ + keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH); + if (IS_ERR(keyring_ref)) { + ret = PTR_ERR(keyring_ref); + goto error2; + } + + /* get the destination keyring if specified */ + dest_ref = NULL; + if (destringid) { + dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, + KEY_NEED_WRITE); + if (IS_ERR(dest_ref)) { + ret = PTR_ERR(dest_ref); + goto error3; + } + } + + /* find the key type */ + ktype = key_type_lookup(type); + if (IS_ERR(ktype)) { + ret = PTR_ERR(ktype); + goto error4; + } + + /* do the search */ + key_ref = keyring_search(keyring_ref, ktype, description); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + + /* treat lack or presence of a negative key the same */ + if (ret == -EAGAIN) + ret = -ENOKEY; + goto error5; + } + + /* link the resulting key to the destination keyring if we can */ + if (dest_ref) { + ret = key_permission(key_ref, KEY_NEED_LINK); + if (ret < 0) + goto error6; + + ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref)); + if (ret < 0) + goto error6; + } + + ret = key_ref_to_ptr(key_ref)->serial; + +error6: + key_ref_put(key_ref); +error5: + key_type_put(ktype); +error4: + key_ref_put(dest_ref); +error3: + key_ref_put(keyring_ref); +error2: + kfree(description); +error: + return ret; +} + +/* + * Call the read method + */ +static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen) +{ + long ret; + + down_read(&key->sem); + ret = key_validate(key); + if (ret == 0) + ret = key->type->read(key, buffer, buflen); + up_read(&key->sem); + return ret; +} + +/* + * Read a key's payload. + * + * The key must either grant the caller Read permission, or it must grant the + * caller Search permission when searched for from the process keyrings. + * + * If successful, we place up to buflen bytes of data into the buffer, if one + * is provided, and return the amount of data that is available in the key, + * irrespective of how much we copied into the buffer. + */ +long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) +{ + struct key *key; + key_ref_t key_ref; + long ret; + char *key_data = NULL; + size_t key_data_len; + + /* find the key first */ + key_ref = lookup_user_key(keyid, 0, 0); + if (IS_ERR(key_ref)) { + ret = -ENOKEY; + goto out; + } + + key = key_ref_to_ptr(key_ref); + + ret = key_read_state(key); + if (ret < 0) + goto key_put_out; /* Negatively instantiated */ + + /* see if we can read it directly */ + ret = key_permission(key_ref, KEY_NEED_READ); + if (ret == 0) + goto can_read_key; + if (ret != -EACCES) + goto key_put_out; + + /* we can't; see if it's searchable from this process's keyrings + * - we automatically take account of the fact that it may be + * dangling off an instantiation key + */ + if (!is_key_possessed(key_ref)) { + ret = -EACCES; + goto key_put_out; + } + + /* the key is probably readable - now try to read it */ +can_read_key: + if (!key->type->read) { + ret = -EOPNOTSUPP; + goto key_put_out; + } + + if (!buffer || !buflen) { + /* Get the key length from the read method */ + ret = __keyctl_read_key(key, NULL, 0); + goto key_put_out; + } + + /* + * Read the data with the semaphore held (since we might sleep) + * to protect against the key being updated or revoked. + * + * Allocating a temporary buffer to hold the keys before + * transferring them to user buffer to avoid potential + * deadlock involving page fault and mmap_sem. + * + * key_data_len = (buflen <= PAGE_SIZE) + * ? buflen : actual length of key data + * + * This prevents allocating arbitrary large buffer which can + * be much larger than the actual key length. In the latter case, + * at least 2 passes of this loop is required. + */ + key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0; + for (;;) { + if (key_data_len) { + key_data = kvmalloc(key_data_len, GFP_KERNEL); + if (!key_data) { + ret = -ENOMEM; + goto key_put_out; + } + } + + ret = __keyctl_read_key(key, key_data, key_data_len); + + /* + * Read methods will just return the required length without + * any copying if the provided length isn't large enough. + */ + if (ret <= 0 || ret > buflen) + break; + + /* + * The key may change (unlikely) in between 2 consecutive + * __keyctl_read_key() calls. In this case, we reallocate + * a larger buffer and redo the key read when + * key_data_len < ret <= buflen. + */ + if (ret > key_data_len) { + if (unlikely(key_data)) + kvfree_sensitive(key_data, key_data_len); + key_data_len = ret; + continue; /* Allocate buffer */ + } + + if (copy_to_user(buffer, key_data, ret)) + ret = -EFAULT; + break; + } + kvfree_sensitive(key_data, key_data_len); + +key_put_out: + key_put(key); +out: + return ret; +} + +/* + * Change the ownership of a key + * + * The key must grant the caller Setattr permission for this to work, though + * the key need not be fully instantiated yet. For the UID to be changed, or + * for the GID to be changed to a group the caller is not a member of, the + * caller must have sysadmin capability. If either uid or gid is -1 then that + * attribute is not changed. + * + * If the UID is to be changed, the new user must have sufficient quota to + * accept the key. The quota deduction will be removed from the old user to + * the new user should the attribute be changed. + * + * If successful, 0 will be returned. + */ +long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) +{ + struct key_user *newowner, *zapowner = NULL; + struct key *key; + key_ref_t key_ref; + long ret; + kuid_t uid; + kgid_t gid; + + uid = make_kuid(current_user_ns(), user); + gid = make_kgid(current_user_ns(), group); + ret = -EINVAL; + if ((user != (uid_t) -1) && !uid_valid(uid)) + goto error; + if ((group != (gid_t) -1) && !gid_valid(gid)) + goto error; + + ret = 0; + if (user == (uid_t) -1 && group == (gid_t) -1) + goto error; + + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, + KEY_NEED_SETATTR); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error; + } + + key = key_ref_to_ptr(key_ref); + + /* make the changes with the locks held to prevent chown/chown races */ + ret = -EACCES; + down_write(&key->sem); + + if (!capable(CAP_SYS_ADMIN)) { + /* only the sysadmin can chown a key to some other UID */ + if (user != (uid_t) -1 && !uid_eq(key->uid, uid)) + goto error_put; + + /* only the sysadmin can set the key's GID to a group other + * than one of those that the current process subscribes to */ + if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid)) + goto error_put; + } + + /* change the UID */ + if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) { + ret = -ENOMEM; + newowner = key_user_lookup(uid); + if (!newowner) + goto error_put; + + /* transfer the quota burden to the new user */ + if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { + unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxkeys : key_quota_maxkeys; + unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxbytes : key_quota_maxbytes; + + spin_lock(&newowner->lock); + if (newowner->qnkeys + 1 > maxkeys || + newowner->qnbytes + key->quotalen > maxbytes || + newowner->qnbytes + key->quotalen < + newowner->qnbytes) + goto quota_overrun; + + newowner->qnkeys++; + newowner->qnbytes += key->quotalen; + spin_unlock(&newowner->lock); + + spin_lock(&key->user->lock); + key->user->qnkeys--; + key->user->qnbytes -= key->quotalen; + spin_unlock(&key->user->lock); + } + + atomic_dec(&key->user->nkeys); + atomic_inc(&newowner->nkeys); + + if (key->state != KEY_IS_UNINSTANTIATED) { + atomic_dec(&key->user->nikeys); + atomic_inc(&newowner->nikeys); + } + + zapowner = key->user; + key->user = newowner; + key->uid = uid; + } + + /* change the GID */ + if (group != (gid_t) -1) + key->gid = gid; + + ret = 0; + +error_put: + up_write(&key->sem); + key_put(key); + if (zapowner) + key_user_put(zapowner); +error: + return ret; + +quota_overrun: + spin_unlock(&newowner->lock); + zapowner = newowner; + ret = -EDQUOT; + goto error_put; +} + +/* + * Change the permission mask on a key. + * + * The key must grant the caller Setattr permission for this to work, though + * the key need not be fully instantiated yet. If the caller does not have + * sysadmin capability, it may only change the permission on keys that it owns. + */ +long keyctl_setperm_key(key_serial_t id, key_perm_t perm) +{ + struct key *key; + key_ref_t key_ref; + long ret; + + ret = -EINVAL; + if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL)) + goto error; + + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, + KEY_NEED_SETATTR); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error; + } + + key = key_ref_to_ptr(key_ref); + + /* make the changes with the locks held to prevent chown/chmod races */ + ret = -EACCES; + down_write(&key->sem); + + /* if we're not the sysadmin, we can only change a key that we own */ + if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) { + key->perm = perm; + ret = 0; + } + + up_write(&key->sem); + key_put(key); +error: + return ret; +} + +/* + * Get the destination keyring for instantiation and check that the caller has + * Write permission on it. + */ +static long get_instantiation_keyring(key_serial_t ringid, + struct request_key_auth *rka, + struct key **_dest_keyring) +{ + key_ref_t dkref; + + *_dest_keyring = NULL; + + /* just return a NULL pointer if we weren't asked to make a link */ + if (ringid == 0) + return 0; + + /* if a specific keyring is nominated by ID, then use that */ + if (ringid > 0) { + dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); + if (IS_ERR(dkref)) + return PTR_ERR(dkref); + *_dest_keyring = key_ref_to_ptr(dkref); + return 0; + } + + if (ringid == KEY_SPEC_REQKEY_AUTH_KEY) + return -EINVAL; + + /* otherwise specify the destination keyring recorded in the + * authorisation key (any KEY_SPEC_*_KEYRING) */ + if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) { + *_dest_keyring = key_get(rka->dest_keyring); + return 0; + } + + return -ENOKEY; +} + +/* + * Change the request_key authorisation key on the current process. + */ +static int keyctl_change_reqkey_auth(struct key *key) +{ + struct cred *new; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + + key_put(new->request_key_auth); + new->request_key_auth = key_get(key); + + return commit_creds(new); +} + +/* + * Instantiate a key with the specified payload and link the key into the + * destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key_common(key_serial_t id, + struct iov_iter *from, + key_serial_t ringid) +{ + const struct cred *cred = current_cred(); + struct request_key_auth *rka; + struct key *instkey, *dest_keyring; + size_t plen = from ? iov_iter_count(from) : 0; + void *payload; + long ret; + + kenter("%d,,%zu,%d", id, plen, ringid); + + if (!plen) + from = NULL; + + ret = -EINVAL; + if (plen > 1024 * 1024 - 1) + goto error; + + /* the appropriate instantiation authorisation key must have been + * assumed before calling this */ + ret = -EPERM; + instkey = cred->request_key_auth; + if (!instkey) + goto error; + + rka = instkey->payload.data[0]; + if (rka->target_key->serial != id) + goto error; + + /* pull the payload in if one was supplied */ + payload = NULL; + + if (from) { + ret = -ENOMEM; + payload = kvmalloc(plen, GFP_KERNEL); + if (!payload) + goto error; + + ret = -EFAULT; + if (!copy_from_iter_full(payload, plen, from)) + goto error2; + } + + /* find the destination keyring amongst those belonging to the + * requesting task */ + ret = get_instantiation_keyring(ringid, rka, &dest_keyring); + if (ret < 0) + goto error2; + + /* instantiate the key and link it into a keyring */ + ret = key_instantiate_and_link(rka->target_key, payload, plen, + dest_keyring, instkey); + + key_put(dest_keyring); + + /* discard the assumed authority if it's just been disabled by + * instantiation of the key */ + if (ret == 0) + keyctl_change_reqkey_auth(NULL); + +error2: + kvfree_sensitive(payload, plen); +error: + return ret; +} + +/* + * Instantiate a key with the specified payload and link the key into the + * destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key(key_serial_t id, + const void __user *_payload, + size_t plen, + key_serial_t ringid) +{ + if (_payload && plen) { + struct iovec iov; + struct iov_iter from; + int ret; + + ret = import_single_range(WRITE, (void __user *)_payload, plen, + &iov, &from); + if (unlikely(ret)) + return ret; + + return keyctl_instantiate_key_common(id, &from, ringid); + } + + return keyctl_instantiate_key_common(id, NULL, ringid); +} + +/* + * Instantiate a key with the specified multipart payload and link the key into + * the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key_iov(key_serial_t id, + const struct iovec __user *_payload_iov, + unsigned ioc, + key_serial_t ringid) +{ + struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; + struct iov_iter from; + long ret; + + if (!_payload_iov) + ioc = 0; + + ret = import_iovec(WRITE, _payload_iov, ioc, + ARRAY_SIZE(iovstack), &iov, &from); + if (ret < 0) + return ret; + ret = keyctl_instantiate_key_common(id, &from, ringid); + kfree(iov); + return ret; +} + +/* + * Negatively instantiate the key with the given timeout (in seconds) and link + * the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return -ENOKEY until the negative key expires. + * + * If successful, 0 will be returned. + */ +long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) +{ + return keyctl_reject_key(id, timeout, ENOKEY, ringid); +} + +/* + * Negatively instantiate the key with the given timeout (in seconds) and error + * code and link the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return the specified error code until the negative key expires. + * + * If successful, 0 will be returned. + */ +long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error, + key_serial_t ringid) +{ + const struct cred *cred = current_cred(); + struct request_key_auth *rka; + struct key *instkey, *dest_keyring; + long ret; + + kenter("%d,%u,%u,%d", id, timeout, error, ringid); + + /* must be a valid error code and mustn't be a kernel special */ + if (error <= 0 || + error >= MAX_ERRNO || + error == ERESTARTSYS || + error == ERESTARTNOINTR || + error == ERESTARTNOHAND || + error == ERESTART_RESTARTBLOCK) + return -EINVAL; + + /* the appropriate instantiation authorisation key must have been + * assumed before calling this */ + ret = -EPERM; + instkey = cred->request_key_auth; + if (!instkey) + goto error; + + rka = instkey->payload.data[0]; + if (rka->target_key->serial != id) + goto error; + + /* find the destination keyring if present (which must also be + * writable) */ + ret = get_instantiation_keyring(ringid, rka, &dest_keyring); + if (ret < 0) + goto error; + + /* instantiate the key and link it into a keyring */ + ret = key_reject_and_link(rka->target_key, timeout, error, + dest_keyring, instkey); + + key_put(dest_keyring); + + /* discard the assumed authority if it's just been disabled by + * instantiation of the key */ + if (ret == 0) + keyctl_change_reqkey_auth(NULL); + +error: + return ret; +} + +/* + * Read or set the default keyring in which request_key() will cache keys and + * return the old setting. + * + * If a thread or process keyring is specified then it will be created if it + * doesn't yet exist. The old setting will be returned if successful. + */ +long keyctl_set_reqkey_keyring(int reqkey_defl) +{ + struct cred *new; + int ret, old_setting; + + old_setting = current_cred_xxx(jit_keyring); + + if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE) + return old_setting; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + + switch (reqkey_defl) { + case KEY_REQKEY_DEFL_THREAD_KEYRING: + ret = install_thread_keyring_to_cred(new); + if (ret < 0) + goto error; + goto set; + + case KEY_REQKEY_DEFL_PROCESS_KEYRING: + ret = install_process_keyring_to_cred(new); + if (ret < 0) + goto error; + goto set; + + case KEY_REQKEY_DEFL_DEFAULT: + case KEY_REQKEY_DEFL_SESSION_KEYRING: + case KEY_REQKEY_DEFL_USER_KEYRING: + case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: + case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: + goto set; + + case KEY_REQKEY_DEFL_NO_CHANGE: + case KEY_REQKEY_DEFL_GROUP_KEYRING: + default: + ret = -EINVAL; + goto error; + } + +set: + new->jit_keyring = reqkey_defl; + commit_creds(new); + return old_setting; +error: + abort_creds(new); + return ret; +} + +/* + * Set or clear the timeout on a key. + * + * Either the key must grant the caller Setattr permission or else the caller + * must hold an instantiation authorisation token for the key. + * + * The timeout is either 0 to clear the timeout, or a number of seconds from + * the current time. The key and any links to the key will be automatically + * garbage collected after the timeout expires. + * + * Keys with KEY_FLAG_KEEP set should not be timed out. + * + * If successful, 0 is returned. + */ +long keyctl_set_timeout(key_serial_t id, unsigned timeout) +{ + struct key *key, *instkey; + key_ref_t key_ref; + long ret; + + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, + KEY_NEED_SETATTR); + if (IS_ERR(key_ref)) { + /* setting the timeout on a key under construction is permitted + * if we have the authorisation token handy */ + if (PTR_ERR(key_ref) == -EACCES) { + instkey = key_get_instantiation_authkey(id); + if (!IS_ERR(instkey)) { + key_put(instkey); + key_ref = lookup_user_key(id, + KEY_LOOKUP_PARTIAL, + 0); + if (!IS_ERR(key_ref)) + goto okay; + } + } + + ret = PTR_ERR(key_ref); + goto error; + } + +okay: + key = key_ref_to_ptr(key_ref); + ret = 0; + if (test_bit(KEY_FLAG_KEEP, &key->flags)) + ret = -EPERM; + else + key_set_timeout(key, timeout); + key_put(key); + +error: + return ret; +} + +/* + * Assume (or clear) the authority to instantiate the specified key. + * + * This sets the authoritative token currently in force for key instantiation. + * This must be done for a key to be instantiated. It has the effect of making + * available all the keys from the caller of the request_key() that created a + * key to request_key() calls made by the caller of this function. + * + * The caller must have the instantiation key in their process keyrings with a + * Search permission grant available to the caller. + * + * If the ID given is 0, then the setting will be cleared and 0 returned. + * + * If the ID given has a matching an authorisation key, then that key will be + * set and its ID will be returned. The authorisation key can be read to get + * the callout information passed to request_key(). + */ +long keyctl_assume_authority(key_serial_t id) +{ + struct key *authkey; + long ret; + + /* special key IDs aren't permitted */ + ret = -EINVAL; + if (id < 0) + goto error; + + /* we divest ourselves of authority if given an ID of 0 */ + if (id == 0) { + ret = keyctl_change_reqkey_auth(NULL); + goto error; + } + + /* attempt to assume the authority temporarily granted to us whilst we + * instantiate the specified key + * - the authorisation key must be in the current task's keyrings + * somewhere + */ + authkey = key_get_instantiation_authkey(id); + if (IS_ERR(authkey)) { + ret = PTR_ERR(authkey); + goto error; + } + + ret = keyctl_change_reqkey_auth(authkey); + if (ret == 0) + ret = authkey->serial; + key_put(authkey); +error: + return ret; +} + +/* + * Get a key's the LSM security label. + * + * The key must grant the caller View permission for this to work. + * + * If there's a buffer, then up to buflen bytes of data will be placed into it. + * + * If successful, the amount of information available will be returned, + * irrespective of how much was copied (including the terminal NUL). + */ +long keyctl_get_security(key_serial_t keyid, + char __user *buffer, + size_t buflen) +{ + struct key *key, *instkey; + key_ref_t key_ref; + char *context; + long ret; + + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW); + if (IS_ERR(key_ref)) { + if (PTR_ERR(key_ref) != -EACCES) + return PTR_ERR(key_ref); + + /* viewing a key under construction is also permitted if we + * have the authorisation token handy */ + instkey = key_get_instantiation_authkey(keyid); + if (IS_ERR(instkey)) + return PTR_ERR(instkey); + key_put(instkey); + + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0); + if (IS_ERR(key_ref)) + return PTR_ERR(key_ref); + } + + key = key_ref_to_ptr(key_ref); + ret = security_key_getsecurity(key, &context); + if (ret == 0) { + /* if no information was returned, give userspace an empty + * string */ + ret = 1; + if (buffer && buflen > 0 && + copy_to_user(buffer, "", 1) != 0) + ret = -EFAULT; + } else if (ret > 0) { + /* return as much data as there's room for */ + if (buffer && buflen > 0) { + if (buflen > ret) + buflen = ret; + + if (copy_to_user(buffer, context, buflen) != 0) + ret = -EFAULT; + } + + kfree(context); + } + + key_ref_put(key_ref); + return ret; +} + +/* + * Attempt to install the calling process's session keyring on the process's + * parent process. + * + * The keyring must exist and must grant the caller LINK permission, and the + * parent process must be single-threaded and must have the same effective + * ownership as this process and mustn't be SUID/SGID. + * + * The keyring will be emplaced on the parent when it next resumes userspace. + * + * If successful, 0 will be returned. + */ +long keyctl_session_to_parent(void) +{ + struct task_struct *me, *parent; + const struct cred *mycred, *pcred; + struct callback_head *newwork, *oldwork; + key_ref_t keyring_r; + struct cred *cred; + int ret; + + keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK); + if (IS_ERR(keyring_r)) + return PTR_ERR(keyring_r); + + ret = -ENOMEM; + + /* our parent is going to need a new cred struct, a new tgcred struct + * and new security data, so we allocate them here to prevent ENOMEM in + * our parent */ + cred = cred_alloc_blank(); + if (!cred) + goto error_keyring; + newwork = &cred->rcu; + + cred->session_keyring = key_ref_to_ptr(keyring_r); + keyring_r = NULL; + init_task_work(newwork, key_change_session_keyring); + + me = current; + rcu_read_lock(); + write_lock_irq(&tasklist_lock); + + ret = -EPERM; + oldwork = NULL; + parent = me->real_parent; + + /* the parent mustn't be init and mustn't be a kernel thread */ + if (parent->pid <= 1 || !parent->mm) + goto unlock; + + /* the parent must be single threaded */ + if (!thread_group_empty(parent)) + goto unlock; + + /* the parent and the child must have different session keyrings or + * there's no point */ + mycred = current_cred(); + pcred = __task_cred(parent); + if (mycred == pcred || + mycred->session_keyring == pcred->session_keyring) { + ret = 0; + goto unlock; + } + + /* the parent must have the same effective ownership and mustn't be + * SUID/SGID */ + if (!uid_eq(pcred->uid, mycred->euid) || + !uid_eq(pcred->euid, mycred->euid) || + !uid_eq(pcred->suid, mycred->euid) || + !gid_eq(pcred->gid, mycred->egid) || + !gid_eq(pcred->egid, mycred->egid) || + !gid_eq(pcred->sgid, mycred->egid)) + goto unlock; + + /* the keyrings must have the same UID */ + if ((pcred->session_keyring && + !uid_eq(pcred->session_keyring->uid, mycred->euid)) || + !uid_eq(mycred->session_keyring->uid, mycred->euid)) + goto unlock; + + /* cancel an already pending keyring replacement */ + oldwork = task_work_cancel(parent, key_change_session_keyring); + + /* the replacement session keyring is applied just prior to userspace + * restarting */ + ret = task_work_add(parent, newwork, true); + if (!ret) + newwork = NULL; +unlock: + write_unlock_irq(&tasklist_lock); + rcu_read_unlock(); + if (oldwork) + put_cred(container_of(oldwork, struct cred, rcu)); + if (newwork) + put_cred(cred); + return ret; + +error_keyring: + key_ref_put(keyring_r); + return ret; +} + +/* + * Apply a restriction to a given keyring. + * + * The caller must have Setattr permission to change keyring restrictions. + * + * The requested type name may be a NULL pointer to reject all attempts + * to link to the keyring. In this case, _restriction must also be NULL. + * Otherwise, both _type and _restriction must be non-NULL. + * + * Returns 0 if successful. + */ +long keyctl_restrict_keyring(key_serial_t id, const char __user *_type, + const char __user *_restriction) +{ + key_ref_t key_ref; + char type[32]; + char *restriction = NULL; + long ret; + + key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR); + if (IS_ERR(key_ref)) + return PTR_ERR(key_ref); + + ret = -EINVAL; + if (_type) { + if (!_restriction) + goto error; + + ret = key_get_type_from_user(type, _type, sizeof(type)); + if (ret < 0) + goto error; + + restriction = strndup_user(_restriction, PAGE_SIZE); + if (IS_ERR(restriction)) { + ret = PTR_ERR(restriction); + goto error; + } + } else { + if (_restriction) + goto error; + } + + ret = keyring_restrict(key_ref, _type ? type : NULL, restriction); + kfree(restriction); +error: + key_ref_put(key_ref); + return ret; +} + +/* + * The key control system call + */ +SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, + unsigned long, arg4, unsigned long, arg5) +{ + switch (option) { + case KEYCTL_GET_KEYRING_ID: + return keyctl_get_keyring_ID((key_serial_t) arg2, + (int) arg3); + + case KEYCTL_JOIN_SESSION_KEYRING: + return keyctl_join_session_keyring((const char __user *) arg2); + + case KEYCTL_UPDATE: + return keyctl_update_key((key_serial_t) arg2, + (const void __user *) arg3, + (size_t) arg4); + + case KEYCTL_REVOKE: + return keyctl_revoke_key((key_serial_t) arg2); + + case KEYCTL_DESCRIBE: + return keyctl_describe_key((key_serial_t) arg2, + (char __user *) arg3, + (unsigned) arg4); + + case KEYCTL_CLEAR: + return keyctl_keyring_clear((key_serial_t) arg2); + + case KEYCTL_LINK: + return keyctl_keyring_link((key_serial_t) arg2, + (key_serial_t) arg3); + + case KEYCTL_UNLINK: + return keyctl_keyring_unlink((key_serial_t) arg2, + (key_serial_t) arg3); + + case KEYCTL_SEARCH: + return keyctl_keyring_search((key_serial_t) arg2, + (const char __user *) arg3, + (const char __user *) arg4, + (key_serial_t) arg5); + + case KEYCTL_READ: + return keyctl_read_key((key_serial_t) arg2, + (char __user *) arg3, + (size_t) arg4); + + case KEYCTL_CHOWN: + return keyctl_chown_key((key_serial_t) arg2, + (uid_t) arg3, + (gid_t) arg4); + + case KEYCTL_SETPERM: + return keyctl_setperm_key((key_serial_t) arg2, + (key_perm_t) arg3); + + case KEYCTL_INSTANTIATE: + return keyctl_instantiate_key((key_serial_t) arg2, + (const void __user *) arg3, + (size_t) arg4, + (key_serial_t) arg5); + + case KEYCTL_NEGATE: + return keyctl_negate_key((key_serial_t) arg2, + (unsigned) arg3, + (key_serial_t) arg4); + + case KEYCTL_SET_REQKEY_KEYRING: + return keyctl_set_reqkey_keyring(arg2); + + case KEYCTL_SET_TIMEOUT: + return keyctl_set_timeout((key_serial_t) arg2, + (unsigned) arg3); + + case KEYCTL_ASSUME_AUTHORITY: + return keyctl_assume_authority((key_serial_t) arg2); + + case KEYCTL_GET_SECURITY: + return keyctl_get_security((key_serial_t) arg2, + (char __user *) arg3, + (size_t) arg4); + + case KEYCTL_SESSION_TO_PARENT: + return keyctl_session_to_parent(); + + case KEYCTL_REJECT: + return keyctl_reject_key((key_serial_t) arg2, + (unsigned) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + + case KEYCTL_INSTANTIATE_IOV: + return keyctl_instantiate_key_iov( + (key_serial_t) arg2, + (const struct iovec __user *) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + + case KEYCTL_INVALIDATE: + return keyctl_invalidate_key((key_serial_t) arg2); + + case KEYCTL_GET_PERSISTENT: + return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3); + + case KEYCTL_DH_COMPUTE: + return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2, + (char __user *) arg3, (size_t) arg4, + (struct keyctl_kdf_params __user *) arg5); + + case KEYCTL_RESTRICT_KEYRING: + return keyctl_restrict_keyring((key_serial_t) arg2, + (const char __user *) arg3, + (const char __user *) arg4); + + default: + return -EOPNOTSUPP; + } +} diff --git a/security/keys/keyring.c b/security/keys/keyring.c new file mode 100644 index 000000000..e8f236602 --- /dev/null +++ b/security/keys/keyring.c @@ -0,0 +1,1580 @@ +/* Keyring handling + * + * Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/security.h> +#include <linux/seq_file.h> +#include <linux/err.h> +#include <keys/keyring-type.h> +#include <keys/user-type.h> +#include <linux/assoc_array_priv.h> +#include <linux/uaccess.h> +#include "internal.h" + +/* + * When plumbing the depths of the key tree, this sets a hard limit + * set on how deep we're willing to go. + */ +#define KEYRING_SEARCH_MAX_DEPTH 6 + +/* + * We keep all named keyrings in a hash to speed looking them up. + */ +#define KEYRING_NAME_HASH_SIZE (1 << 5) + +/* + * We mark pointers we pass to the associative array with bit 1 set if + * they're keyrings and clear otherwise. + */ +#define KEYRING_PTR_SUBTYPE 0x2UL + +static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr *x) +{ + return (unsigned long)x & KEYRING_PTR_SUBTYPE; +} +static inline struct key *keyring_ptr_to_key(const struct assoc_array_ptr *x) +{ + void *object = assoc_array_ptr_to_leaf(x); + return (struct key *)((unsigned long)object & ~KEYRING_PTR_SUBTYPE); +} +static inline void *keyring_key_to_ptr(struct key *key) +{ + if (key->type == &key_type_keyring) + return (void *)((unsigned long)key | KEYRING_PTR_SUBTYPE); + return key; +} + +static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE]; +static DEFINE_RWLOCK(keyring_name_lock); + +static inline unsigned keyring_hash(const char *desc) +{ + unsigned bucket = 0; + + for (; *desc; desc++) + bucket += (unsigned char)*desc; + + return bucket & (KEYRING_NAME_HASH_SIZE - 1); +} + +/* + * The keyring key type definition. Keyrings are simply keys of this type and + * can be treated as ordinary keys in addition to having their own special + * operations. + */ +static int keyring_preparse(struct key_preparsed_payload *prep); +static void keyring_free_preparse(struct key_preparsed_payload *prep); +static int keyring_instantiate(struct key *keyring, + struct key_preparsed_payload *prep); +static void keyring_revoke(struct key *keyring); +static void keyring_destroy(struct key *keyring); +static void keyring_describe(const struct key *keyring, struct seq_file *m); +static long keyring_read(const struct key *keyring, + char __user *buffer, size_t buflen); + +struct key_type key_type_keyring = { + .name = "keyring", + .def_datalen = 0, + .preparse = keyring_preparse, + .free_preparse = keyring_free_preparse, + .instantiate = keyring_instantiate, + .revoke = keyring_revoke, + .destroy = keyring_destroy, + .describe = keyring_describe, + .read = keyring_read, +}; +EXPORT_SYMBOL(key_type_keyring); + +/* + * Semaphore to serialise link/link calls to prevent two link calls in parallel + * introducing a cycle. + */ +static DECLARE_RWSEM(keyring_serialise_link_sem); + +/* + * Publish the name of a keyring so that it can be found by name (if it has + * one). + */ +static void keyring_publish_name(struct key *keyring) +{ + int bucket; + + if (keyring->description) { + bucket = keyring_hash(keyring->description); + + write_lock(&keyring_name_lock); + + if (!keyring_name_hash[bucket].next) + INIT_LIST_HEAD(&keyring_name_hash[bucket]); + + list_add_tail(&keyring->name_link, + &keyring_name_hash[bucket]); + + write_unlock(&keyring_name_lock); + } +} + +/* + * Preparse a keyring payload + */ +static int keyring_preparse(struct key_preparsed_payload *prep) +{ + return prep->datalen != 0 ? -EINVAL : 0; +} + +/* + * Free a preparse of a user defined key payload + */ +static void keyring_free_preparse(struct key_preparsed_payload *prep) +{ +} + +/* + * Initialise a keyring. + * + * Returns 0 on success, -EINVAL if given any data. + */ +static int keyring_instantiate(struct key *keyring, + struct key_preparsed_payload *prep) +{ + assoc_array_init(&keyring->keys); + /* make the keyring available by name if it has one */ + keyring_publish_name(keyring); + return 0; +} + +/* + * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd + * fold the carry back too, but that requires inline asm. + */ +static u64 mult_64x32_and_fold(u64 x, u32 y) +{ + u64 hi = (u64)(u32)(x >> 32) * y; + u64 lo = (u64)(u32)(x) * y; + return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32); +} + +/* + * Hash a key type and description. + */ +static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) +{ + const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; + const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK; + const char *description = index_key->description; + unsigned long hash, type; + u32 piece; + u64 acc; + int n, desc_len = index_key->desc_len; + + type = (unsigned long)index_key->type; + + acc = mult_64x32_and_fold(type, desc_len + 13); + acc = mult_64x32_and_fold(acc, 9207); + for (;;) { + n = desc_len; + if (n <= 0) + break; + if (n > 4) + n = 4; + piece = 0; + memcpy(&piece, description, n); + description += n; + desc_len -= n; + acc = mult_64x32_and_fold(acc, piece); + acc = mult_64x32_and_fold(acc, 9207); + } + + /* Fold the hash down to 32 bits if need be. */ + hash = acc; + if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32) + hash ^= acc >> 32; + + /* Squidge all the keyrings into a separate part of the tree to + * ordinary keys by making sure the lowest level segment in the hash is + * zero for keyrings and non-zero otherwise. + */ + if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0) + return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; + if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) + return (hash + (hash << level_shift)) & ~fan_mask; + return hash; +} + +/* + * Build the next index key chunk. + * + * On 32-bit systems the index key is laid out as: + * + * 0 4 5 9... + * hash desclen typeptr desc[] + * + * On 64-bit systems: + * + * 0 8 9 17... + * hash desclen typeptr desc[] + * + * We return it one word-sized chunk at a time. + */ +static unsigned long keyring_get_key_chunk(const void *data, int level) +{ + const struct keyring_index_key *index_key = data; + unsigned long chunk = 0; + long offset = 0; + int desc_len = index_key->desc_len, n = sizeof(chunk); + + level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; + switch (level) { + case 0: + return hash_key_type_and_desc(index_key); + case 1: + return ((unsigned long)index_key->type << 8) | desc_len; + case 2: + if (desc_len == 0) + return (u8)((unsigned long)index_key->type >> + (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); + n--; + offset = 1; + default: + offset += sizeof(chunk) - 1; + offset += (level - 3) * sizeof(chunk); + if (offset >= desc_len) + return 0; + desc_len -= offset; + if (desc_len > n) + desc_len = n; + offset += desc_len; + do { + chunk <<= 8; + chunk |= ((u8*)index_key->description)[--offset]; + } while (--desc_len > 0); + + if (level == 2) { + chunk <<= 8; + chunk |= (u8)((unsigned long)index_key->type >> + (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); + } + return chunk; + } +} + +static unsigned long keyring_get_object_key_chunk(const void *object, int level) +{ + const struct key *key = keyring_ptr_to_key(object); + return keyring_get_key_chunk(&key->index_key, level); +} + +static bool keyring_compare_object(const void *object, const void *data) +{ + const struct keyring_index_key *index_key = data; + const struct key *key = keyring_ptr_to_key(object); + + return key->index_key.type == index_key->type && + key->index_key.desc_len == index_key->desc_len && + memcmp(key->index_key.description, index_key->description, + index_key->desc_len) == 0; +} + +/* + * Compare the index keys of a pair of objects and determine the bit position + * at which they differ - if they differ. + */ +static int keyring_diff_objects(const void *object, const void *data) +{ + const struct key *key_a = keyring_ptr_to_key(object); + const struct keyring_index_key *a = &key_a->index_key; + const struct keyring_index_key *b = data; + unsigned long seg_a, seg_b; + int level, i; + + level = 0; + seg_a = hash_key_type_and_desc(a); + seg_b = hash_key_type_and_desc(b); + if ((seg_a ^ seg_b) != 0) + goto differ; + + /* The number of bits contributed by the hash is controlled by a + * constant in the assoc_array headers. Everything else thereafter we + * can deal with as being machine word-size dependent. + */ + level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8; + seg_a = a->desc_len; + seg_b = b->desc_len; + if ((seg_a ^ seg_b) != 0) + goto differ; + + /* The next bit may not work on big endian */ + level++; + seg_a = (unsigned long)a->type; + seg_b = (unsigned long)b->type; + if ((seg_a ^ seg_b) != 0) + goto differ; + + level += sizeof(unsigned long); + if (a->desc_len == 0) + goto same; + + i = 0; + if (((unsigned long)a->description | (unsigned long)b->description) & + (sizeof(unsigned long) - 1)) { + do { + seg_a = *(unsigned long *)(a->description + i); + seg_b = *(unsigned long *)(b->description + i); + if ((seg_a ^ seg_b) != 0) + goto differ_plus_i; + i += sizeof(unsigned long); + } while (i < (a->desc_len & (sizeof(unsigned long) - 1))); + } + + for (; i < a->desc_len; i++) { + seg_a = *(unsigned char *)(a->description + i); + seg_b = *(unsigned char *)(b->description + i); + if ((seg_a ^ seg_b) != 0) + goto differ_plus_i; + } + +same: + return -1; + +differ_plus_i: + level += i; +differ: + i = level * 8 + __ffs(seg_a ^ seg_b); + return i; +} + +/* + * Free an object after stripping the keyring flag off of the pointer. + */ +static void keyring_free_object(void *object) +{ + key_put(keyring_ptr_to_key(object)); +} + +/* + * Operations for keyring management by the index-tree routines. + */ +static const struct assoc_array_ops keyring_assoc_array_ops = { + .get_key_chunk = keyring_get_key_chunk, + .get_object_key_chunk = keyring_get_object_key_chunk, + .compare_object = keyring_compare_object, + .diff_objects = keyring_diff_objects, + .free_object = keyring_free_object, +}; + +/* + * Clean up a keyring when it is destroyed. Unpublish its name if it had one + * and dispose of its data. + * + * The garbage collector detects the final key_put(), removes the keyring from + * the serial number tree and then does RCU synchronisation before coming here, + * so we shouldn't need to worry about code poking around here with the RCU + * readlock held by this time. + */ +static void keyring_destroy(struct key *keyring) +{ + if (keyring->description) { + write_lock(&keyring_name_lock); + + if (keyring->name_link.next != NULL && + !list_empty(&keyring->name_link)) + list_del(&keyring->name_link); + + write_unlock(&keyring_name_lock); + } + + if (keyring->restrict_link) { + struct key_restriction *keyres = keyring->restrict_link; + + key_put(keyres->key); + kfree(keyres); + } + + assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); +} + +/* + * Describe a keyring for /proc. + */ +static void keyring_describe(const struct key *keyring, struct seq_file *m) +{ + if (keyring->description) + seq_puts(m, keyring->description); + else + seq_puts(m, "[anon]"); + + if (key_is_positive(keyring)) { + if (keyring->keys.nr_leaves_on_tree != 0) + seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); + else + seq_puts(m, ": empty"); + } +} + +struct keyring_read_iterator_context { + size_t buflen; + size_t count; + key_serial_t __user *buffer; +}; + +static int keyring_read_iterator(const void *object, void *data) +{ + struct keyring_read_iterator_context *ctx = data; + const struct key *key = keyring_ptr_to_key(object); + + kenter("{%s,%d},,{%zu/%zu}", + key->type->name, key->serial, ctx->count, ctx->buflen); + + if (ctx->count >= ctx->buflen) + return 1; + + *ctx->buffer++ = key->serial; + ctx->count += sizeof(key->serial); + return 0; +} + +/* + * Read a list of key IDs from the keyring's contents in binary form + * + * The keyring's semaphore is read-locked by the caller. This prevents someone + * from modifying it under us - which could cause us to read key IDs multiple + * times. + */ +static long keyring_read(const struct key *keyring, + char __user *buffer, size_t buflen) +{ + struct keyring_read_iterator_context ctx; + long ret; + + kenter("{%d},,%zu", key_serial(keyring), buflen); + + if (buflen & (sizeof(key_serial_t) - 1)) + return -EINVAL; + + /* Copy as many key IDs as fit into the buffer */ + if (buffer && buflen) { + ctx.buffer = (key_serial_t __user *)buffer; + ctx.buflen = buflen; + ctx.count = 0; + ret = assoc_array_iterate(&keyring->keys, + keyring_read_iterator, &ctx); + if (ret < 0) { + kleave(" = %ld [iterate]", ret); + return ret; + } + } + + /* Return the size of the buffer needed */ + ret = keyring->keys.nr_leaves_on_tree * sizeof(key_serial_t); + if (ret <= buflen) + kleave("= %ld [ok]", ret); + else + kleave("= %ld [buffer too small]", ret); + return ret; +} + +/* + * Allocate a keyring and link into the destination keyring. + */ +struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, + const struct cred *cred, key_perm_t perm, + unsigned long flags, + struct key_restriction *restrict_link, + struct key *dest) +{ + struct key *keyring; + int ret; + + keyring = key_alloc(&key_type_keyring, description, + uid, gid, cred, perm, flags, restrict_link); + if (!IS_ERR(keyring)) { + ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); + if (ret < 0) { + key_put(keyring); + keyring = ERR_PTR(ret); + } + } + + return keyring; +} +EXPORT_SYMBOL(keyring_alloc); + +/** + * restrict_link_reject - Give -EPERM to restrict link + * @keyring: The keyring being added to. + * @type: The type of key being added. + * @payload: The payload of the key intended to be added. + * @data: Additional data for evaluating restriction. + * + * Reject the addition of any links to a keyring. It can be overridden by + * passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when + * adding a key to a keyring. + * + * This is meant to be stored in a key_restriction structure which is passed + * in the restrict_link parameter to keyring_alloc(). + */ +int restrict_link_reject(struct key *keyring, + const struct key_type *type, + const union key_payload *payload, + struct key *restriction_key) +{ + return -EPERM; +} + +/* + * By default, we keys found by getting an exact match on their descriptions. + */ +bool key_default_cmp(const struct key *key, + const struct key_match_data *match_data) +{ + return strcmp(key->description, match_data->raw_data) == 0; +} + +/* + * Iteration function to consider each key found. + */ +static int keyring_search_iterator(const void *object, void *iterator_data) +{ + struct keyring_search_context *ctx = iterator_data; + const struct key *key = keyring_ptr_to_key(object); + unsigned long kflags = READ_ONCE(key->flags); + short state = READ_ONCE(key->state); + + kenter("{%d}", key->serial); + + /* ignore keys not of this type */ + if (key->type != ctx->index_key.type) { + kleave(" = 0 [!type]"); + return 0; + } + + /* skip invalidated, revoked and expired keys */ + if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { + time64_t expiry = READ_ONCE(key->expiry); + + if (kflags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) { + ctx->result = ERR_PTR(-EKEYREVOKED); + kleave(" = %d [invrev]", ctx->skipped_ret); + goto skipped; + } + + if (expiry && ctx->now >= expiry) { + if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED)) + ctx->result = ERR_PTR(-EKEYEXPIRED); + kleave(" = %d [expire]", ctx->skipped_ret); + goto skipped; + } + } + + /* keys that don't match */ + if (!ctx->match_data.cmp(key, &ctx->match_data)) { + kleave(" = 0 [!match]"); + return 0; + } + + /* key must have search permissions */ + if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && + key_task_permission(make_key_ref(key, ctx->possessed), + ctx->cred, KEY_NEED_SEARCH) < 0) { + ctx->result = ERR_PTR(-EACCES); + kleave(" = %d [!perm]", ctx->skipped_ret); + goto skipped; + } + + if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { + /* we set a different error code if we pass a negative key */ + if (state < 0) { + ctx->result = ERR_PTR(state); + kleave(" = %d [neg]", ctx->skipped_ret); + goto skipped; + } + } + + /* Found */ + ctx->result = make_key_ref(key, ctx->possessed); + kleave(" = 1 [found]"); + return 1; + +skipped: + return ctx->skipped_ret; +} + +/* + * Search inside a keyring for a key. We can search by walking to it + * directly based on its index-key or we can iterate over the entire + * tree looking for it, based on the match function. + */ +static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) +{ + if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) { + const void *object; + + object = assoc_array_find(&keyring->keys, + &keyring_assoc_array_ops, + &ctx->index_key); + return object ? ctx->iterator(object, ctx) : 0; + } + return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); +} + +/* + * Search a tree of keyrings that point to other keyrings up to the maximum + * depth. + */ +static bool search_nested_keyrings(struct key *keyring, + struct keyring_search_context *ctx) +{ + struct { + struct key *keyring; + struct assoc_array_node *node; + int slot; + } stack[KEYRING_SEARCH_MAX_DEPTH]; + + struct assoc_array_shortcut *shortcut; + struct assoc_array_node *node; + struct assoc_array_ptr *ptr; + struct key *key; + int sp = 0, slot; + + kenter("{%d},{%s,%s}", + keyring->serial, + ctx->index_key.type->name, + ctx->index_key.description); + +#define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK) + BUG_ON((ctx->flags & STATE_CHECKS) == 0 || + (ctx->flags & STATE_CHECKS) == STATE_CHECKS); + + /* Check to see if this top-level keyring is what we are looking for + * and whether it is valid or not. + */ + if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE || + keyring_compare_object(keyring, &ctx->index_key)) { + ctx->skipped_ret = 2; + switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { + case 1: + goto found; + case 2: + return false; + default: + break; + } + } + + ctx->skipped_ret = 0; + + /* Start processing a new keyring */ +descend_to_keyring: + kdebug("descend to %d", keyring->serial); + if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) + goto not_this_keyring; + + /* Search through the keys in this keyring before its searching its + * subtrees. + */ + if (search_keyring(keyring, ctx)) + goto found; + + /* Then manually iterate through the keyrings nested in this one. + * + * Start from the root node of the index tree. Because of the way the + * hash function has been set up, keyrings cluster on the leftmost + * branch of the root node (root slot 0) or in the root node itself. + * Non-keyrings avoid the leftmost branch of the root entirely (root + * slots 1-15). + */ + ptr = READ_ONCE(keyring->keys.root); + if (!ptr) + goto not_this_keyring; + + if (assoc_array_ptr_is_shortcut(ptr)) { + /* If the root is a shortcut, either the keyring only contains + * keyring pointers (everything clusters behind root slot 0) or + * doesn't contain any keyring pointers. + */ + shortcut = assoc_array_ptr_to_shortcut(ptr); + if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) + goto not_this_keyring; + + ptr = READ_ONCE(shortcut->next_node); + node = assoc_array_ptr_to_node(ptr); + goto begin_node; + } + + node = assoc_array_ptr_to_node(ptr); + ptr = node->slots[0]; + if (!assoc_array_ptr_is_meta(ptr)) + goto begin_node; + +descend_to_node: + /* Descend to a more distal node in this keyring's content tree and go + * through that. + */ + kdebug("descend"); + if (assoc_array_ptr_is_shortcut(ptr)) { + shortcut = assoc_array_ptr_to_shortcut(ptr); + ptr = READ_ONCE(shortcut->next_node); + BUG_ON(!assoc_array_ptr_is_node(ptr)); + } + node = assoc_array_ptr_to_node(ptr); + +begin_node: + kdebug("begin_node"); + slot = 0; +ascend_to_node: + /* Go through the slots in a node */ + for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { + ptr = READ_ONCE(node->slots[slot]); + + if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) + goto descend_to_node; + + if (!keyring_ptr_is_keyring(ptr)) + continue; + + key = keyring_ptr_to_key(ptr); + + if (sp >= KEYRING_SEARCH_MAX_DEPTH) { + if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { + ctx->result = ERR_PTR(-ELOOP); + return false; + } + goto not_this_keyring; + } + + /* Search a nested keyring */ + if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && + key_task_permission(make_key_ref(key, ctx->possessed), + ctx->cred, KEY_NEED_SEARCH) < 0) + continue; + + /* stack the current position */ + stack[sp].keyring = keyring; + stack[sp].node = node; + stack[sp].slot = slot; + sp++; + + /* begin again with the new keyring */ + keyring = key; + goto descend_to_keyring; + } + + /* We've dealt with all the slots in the current node, so now we need + * to ascend to the parent and continue processing there. + */ + ptr = READ_ONCE(node->back_pointer); + slot = node->parent_slot; + + if (ptr && assoc_array_ptr_is_shortcut(ptr)) { + shortcut = assoc_array_ptr_to_shortcut(ptr); + ptr = READ_ONCE(shortcut->back_pointer); + slot = shortcut->parent_slot; + } + if (!ptr) + goto not_this_keyring; + node = assoc_array_ptr_to_node(ptr); + slot++; + + /* If we've ascended to the root (zero backpointer), we must have just + * finished processing the leftmost branch rather than the root slots - + * so there can't be any more keyrings for us to find. + */ + if (node->back_pointer) { + kdebug("ascend %d", slot); + goto ascend_to_node; + } + + /* The keyring we're looking at was disqualified or didn't contain a + * matching key. + */ +not_this_keyring: + kdebug("not_this_keyring %d", sp); + if (sp <= 0) { + kleave(" = false"); + return false; + } + + /* Resume the processing of a keyring higher up in the tree */ + sp--; + keyring = stack[sp].keyring; + node = stack[sp].node; + slot = stack[sp].slot + 1; + kdebug("ascend to %d [%d]", keyring->serial, slot); + goto ascend_to_node; + + /* We found a viable match */ +found: + key = key_ref_to_ptr(ctx->result); + key_check(key); + if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { + key->last_used_at = ctx->now; + keyring->last_used_at = ctx->now; + while (sp > 0) + stack[--sp].keyring->last_used_at = ctx->now; + } + kleave(" = true"); + return true; +} + +/** + * keyring_search_aux - Search a keyring tree for a key matching some criteria + * @keyring_ref: A pointer to the keyring with possession indicator. + * @ctx: The keyring search context. + * + * Search the supplied keyring tree for a key that matches the criteria given. + * The root keyring and any linked keyrings must grant Search permission to the + * caller to be searchable and keys can only be found if they too grant Search + * to the caller. The possession flag on the root keyring pointer controls use + * of the possessor bits in permissions checking of the entire tree. In + * addition, the LSM gets to forbid keyring searches and key matches. + * + * The search is performed as a breadth-then-depth search up to the prescribed + * limit (KEYRING_SEARCH_MAX_DEPTH). + * + * Keys are matched to the type provided and are then filtered by the match + * function, which is given the description to use in any way it sees fit. The + * match function may use any attributes of a key that it wishes to to + * determine the match. Normally the match function from the key type would be + * used. + * + * RCU can be used to prevent the keyring key lists from disappearing without + * the need to take lots of locks. + * + * Returns a pointer to the found key and increments the key usage count if + * successful; -EAGAIN if no matching keys were found, or if expired or revoked + * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the + * specified keyring wasn't a keyring. + * + * In the case of a successful return, the possession attribute from + * @keyring_ref is propagated to the returned key reference. + */ +key_ref_t keyring_search_aux(key_ref_t keyring_ref, + struct keyring_search_context *ctx) +{ + struct key *keyring; + long err; + + ctx->iterator = keyring_search_iterator; + ctx->possessed = is_key_possessed(keyring_ref); + ctx->result = ERR_PTR(-EAGAIN); + + keyring = key_ref_to_ptr(keyring_ref); + key_check(keyring); + + if (keyring->type != &key_type_keyring) + return ERR_PTR(-ENOTDIR); + + if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { + err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); + if (err < 0) + return ERR_PTR(err); + } + + rcu_read_lock(); + ctx->now = ktime_get_real_seconds(); + if (search_nested_keyrings(keyring, ctx)) + __key_get(key_ref_to_ptr(ctx->result)); + rcu_read_unlock(); + return ctx->result; +} + +/** + * keyring_search - Search the supplied keyring tree for a matching key + * @keyring: The root of the keyring tree to be searched. + * @type: The type of keyring we want to find. + * @description: The name of the keyring we want to find. + * + * As keyring_search_aux() above, but using the current task's credentials and + * type's default matching function and preferred search method. + */ +key_ref_t keyring_search(key_ref_t keyring, + struct key_type *type, + const char *description) +{ + struct keyring_search_context ctx = { + .index_key.type = type, + .index_key.description = description, + .index_key.desc_len = strlen(description), + .cred = current_cred(), + .match_data.cmp = key_default_cmp, + .match_data.raw_data = description, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = KEYRING_SEARCH_DO_STATE_CHECK, + }; + key_ref_t key; + int ret; + + if (type->match_preparse) { + ret = type->match_preparse(&ctx.match_data); + if (ret < 0) + return ERR_PTR(ret); + } + + key = keyring_search_aux(keyring, &ctx); + + if (type->match_free) + type->match_free(&ctx.match_data); + return key; +} +EXPORT_SYMBOL(keyring_search); + +static struct key_restriction *keyring_restriction_alloc( + key_restrict_link_func_t check) +{ + struct key_restriction *keyres = + kzalloc(sizeof(struct key_restriction), GFP_KERNEL); + + if (!keyres) + return ERR_PTR(-ENOMEM); + + keyres->check = check; + + return keyres; +} + +/* + * Semaphore to serialise restriction setup to prevent reference count + * cycles through restriction key pointers. + */ +static DECLARE_RWSEM(keyring_serialise_restrict_sem); + +/* + * Check for restriction cycles that would prevent keyring garbage collection. + * keyring_serialise_restrict_sem must be held. + */ +static bool keyring_detect_restriction_cycle(const struct key *dest_keyring, + struct key_restriction *keyres) +{ + while (keyres && keyres->key && + keyres->key->type == &key_type_keyring) { + if (keyres->key == dest_keyring) + return true; + + keyres = keyres->key->restrict_link; + } + + return false; +} + +/** + * keyring_restrict - Look up and apply a restriction to a keyring + * + * @keyring: The keyring to be restricted + * @restriction: The restriction options to apply to the keyring + */ +int keyring_restrict(key_ref_t keyring_ref, const char *type, + const char *restriction) +{ + struct key *keyring; + struct key_type *restrict_type = NULL; + struct key_restriction *restrict_link; + int ret = 0; + + keyring = key_ref_to_ptr(keyring_ref); + key_check(keyring); + + if (keyring->type != &key_type_keyring) + return -ENOTDIR; + + if (!type) { + restrict_link = keyring_restriction_alloc(restrict_link_reject); + } else { + restrict_type = key_type_lookup(type); + + if (IS_ERR(restrict_type)) + return PTR_ERR(restrict_type); + + if (!restrict_type->lookup_restriction) { + ret = -ENOENT; + goto error; + } + + restrict_link = restrict_type->lookup_restriction(restriction); + } + + if (IS_ERR(restrict_link)) { + ret = PTR_ERR(restrict_link); + goto error; + } + + down_write(&keyring->sem); + down_write(&keyring_serialise_restrict_sem); + + if (keyring->restrict_link) + ret = -EEXIST; + else if (keyring_detect_restriction_cycle(keyring, restrict_link)) + ret = -EDEADLK; + else + keyring->restrict_link = restrict_link; + + up_write(&keyring_serialise_restrict_sem); + up_write(&keyring->sem); + + if (ret < 0) { + key_put(restrict_link->key); + kfree(restrict_link); + } + +error: + if (restrict_type) + key_type_put(restrict_type); + + return ret; +} +EXPORT_SYMBOL(keyring_restrict); + +/* + * Search the given keyring for a key that might be updated. + * + * The caller must guarantee that the keyring is a keyring and that the + * permission is granted to modify the keyring as no check is made here. The + * caller must also hold a lock on the keyring semaphore. + * + * Returns a pointer to the found key with usage count incremented if + * successful and returns NULL if not found. Revoked and invalidated keys are + * skipped over. + * + * If successful, the possession indicator is propagated from the keyring ref + * to the returned key reference. + */ +key_ref_t find_key_to_update(key_ref_t keyring_ref, + const struct keyring_index_key *index_key) +{ + struct key *keyring, *key; + const void *object; + + keyring = key_ref_to_ptr(keyring_ref); + + kenter("{%d},{%s,%s}", + keyring->serial, index_key->type->name, index_key->description); + + object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, + index_key); + + if (object) + goto found; + + kleave(" = NULL"); + return NULL; + +found: + key = keyring_ptr_to_key(object); + if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) { + kleave(" = NULL [x]"); + return NULL; + } + __key_get(key); + kleave(" = {%d}", key->serial); + return make_key_ref(key, is_key_possessed(keyring_ref)); +} + +/* + * Find a keyring with the specified name. + * + * Only keyrings that have nonzero refcount, are not revoked, and are owned by a + * user in the current user namespace are considered. If @uid_keyring is %true, + * the keyring additionally must have been allocated as a user or user session + * keyring; otherwise, it must grant Search permission directly to the caller. + * + * Returns a pointer to the keyring with the keyring's refcount having being + * incremented on success. -ENOKEY is returned if a key could not be found. + */ +struct key *find_keyring_by_name(const char *name, bool uid_keyring) +{ + struct key *keyring; + int bucket; + + if (!name) + return ERR_PTR(-EINVAL); + + bucket = keyring_hash(name); + + read_lock(&keyring_name_lock); + + if (keyring_name_hash[bucket].next) { + /* search this hash bucket for a keyring with a matching name + * that's readable and that hasn't been revoked */ + list_for_each_entry(keyring, + &keyring_name_hash[bucket], + name_link + ) { + if (!kuid_has_mapping(current_user_ns(), keyring->user->uid)) + continue; + + if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) + continue; + + if (strcmp(keyring->description, name) != 0) + continue; + + if (uid_keyring) { + if (!test_bit(KEY_FLAG_UID_KEYRING, + &keyring->flags)) + continue; + } else { + if (key_permission(make_key_ref(keyring, 0), + KEY_NEED_SEARCH) < 0) + continue; + } + + /* we've got a match but we might end up racing with + * key_cleanup() if the keyring is currently 'dead' + * (ie. it has a zero usage count) */ + if (!refcount_inc_not_zero(&keyring->usage)) + continue; + keyring->last_used_at = ktime_get_real_seconds(); + goto out; + } + } + + keyring = ERR_PTR(-ENOKEY); +out: + read_unlock(&keyring_name_lock); + return keyring; +} + +static int keyring_detect_cycle_iterator(const void *object, + void *iterator_data) +{ + struct keyring_search_context *ctx = iterator_data; + const struct key *key = keyring_ptr_to_key(object); + + kenter("{%d}", key->serial); + + /* We might get a keyring with matching index-key that is nonetheless a + * different keyring. */ + if (key != ctx->match_data.raw_data) + return 0; + + ctx->result = ERR_PTR(-EDEADLK); + return 1; +} + +/* + * See if a cycle will will be created by inserting acyclic tree B in acyclic + * tree A at the topmost level (ie: as a direct child of A). + * + * Since we are adding B to A at the top level, checking for cycles should just + * be a matter of seeing if node A is somewhere in tree B. + */ +static int keyring_detect_cycle(struct key *A, struct key *B) +{ + struct keyring_search_context ctx = { + .index_key = A->index_key, + .match_data.raw_data = A, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .iterator = keyring_detect_cycle_iterator, + .flags = (KEYRING_SEARCH_NO_STATE_CHECK | + KEYRING_SEARCH_NO_UPDATE_TIME | + KEYRING_SEARCH_NO_CHECK_PERM | + KEYRING_SEARCH_DETECT_TOO_DEEP), + }; + + rcu_read_lock(); + search_nested_keyrings(B, &ctx); + rcu_read_unlock(); + return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); +} + +/* + * Preallocate memory so that a key can be linked into to a keyring. + */ +int __key_link_begin(struct key *keyring, + const struct keyring_index_key *index_key, + struct assoc_array_edit **_edit) + __acquires(&keyring->sem) + __acquires(&keyring_serialise_link_sem) +{ + struct assoc_array_edit *edit; + int ret; + + kenter("%d,%s,%s,", + keyring->serial, index_key->type->name, index_key->description); + + BUG_ON(index_key->desc_len == 0); + + if (keyring->type != &key_type_keyring) + return -ENOTDIR; + + down_write(&keyring->sem); + + ret = -EKEYREVOKED; + if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) + goto error_krsem; + + /* serialise link/link calls to prevent parallel calls causing a cycle + * when linking two keyring in opposite orders */ + if (index_key->type == &key_type_keyring) + down_write(&keyring_serialise_link_sem); + + /* Create an edit script that will insert/replace the key in the + * keyring tree. + */ + edit = assoc_array_insert(&keyring->keys, + &keyring_assoc_array_ops, + index_key, + NULL); + if (IS_ERR(edit)) { + ret = PTR_ERR(edit); + goto error_sem; + } + + /* If we're not replacing a link in-place then we're going to need some + * extra quota. + */ + if (!edit->dead_leaf) { + ret = key_payload_reserve(keyring, + keyring->datalen + KEYQUOTA_LINK_BYTES); + if (ret < 0) + goto error_cancel; + } + + *_edit = edit; + kleave(" = 0"); + return 0; + +error_cancel: + assoc_array_cancel_edit(edit); +error_sem: + if (index_key->type == &key_type_keyring) + up_write(&keyring_serialise_link_sem); +error_krsem: + up_write(&keyring->sem); + kleave(" = %d", ret); + return ret; +} + +/* + * Check already instantiated keys aren't going to be a problem. + * + * The caller must have called __key_link_begin(). Don't need to call this for + * keys that were created since __key_link_begin() was called. + */ +int __key_link_check_live_key(struct key *keyring, struct key *key) +{ + if (key->type == &key_type_keyring) + /* check that we aren't going to create a cycle by linking one + * keyring to another */ + return keyring_detect_cycle(keyring, key); + return 0; +} + +/* + * Link a key into to a keyring. + * + * Must be called with __key_link_begin() having being called. Discards any + * already extant link to matching key if there is one, so that each keyring + * holds at most one link to any given key of a particular type+description + * combination. + */ +void __key_link(struct key *key, struct assoc_array_edit **_edit) +{ + __key_get(key); + assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); + assoc_array_apply_edit(*_edit); + *_edit = NULL; +} + +/* + * Finish linking a key into to a keyring. + * + * Must be called with __key_link_begin() having being called. + */ +void __key_link_end(struct key *keyring, + const struct keyring_index_key *index_key, + struct assoc_array_edit *edit) + __releases(&keyring->sem) + __releases(&keyring_serialise_link_sem) +{ + BUG_ON(index_key->type == NULL); + kenter("%d,%s,", keyring->serial, index_key->type->name); + + if (index_key->type == &key_type_keyring) + up_write(&keyring_serialise_link_sem); + + if (edit) { + if (!edit->dead_leaf) { + key_payload_reserve(keyring, + keyring->datalen - KEYQUOTA_LINK_BYTES); + } + assoc_array_cancel_edit(edit); + } + up_write(&keyring->sem); +} + +/* + * Check addition of keys to restricted keyrings. + */ +static int __key_link_check_restriction(struct key *keyring, struct key *key) +{ + if (!keyring->restrict_link || !keyring->restrict_link->check) + return 0; + return keyring->restrict_link->check(keyring, key->type, &key->payload, + keyring->restrict_link->key); +} + +/** + * key_link - Link a key to a keyring + * @keyring: The keyring to make the link in. + * @key: The key to link to. + * + * Make a link in a keyring to a key, such that the keyring holds a reference + * on that key and the key can potentially be found by searching that keyring. + * + * This function will write-lock the keyring's semaphore and will consume some + * of the user's key data quota to hold the link. + * + * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, + * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is + * full, -EDQUOT if there is insufficient key data quota remaining to add + * another link or -ENOMEM if there's insufficient memory. + * + * It is assumed that the caller has checked that it is permitted for a link to + * be made (the keyring should have Write permission and the key Link + * permission). + */ +int key_link(struct key *keyring, struct key *key) +{ + struct assoc_array_edit *edit; + int ret; + + kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage)); + + key_check(keyring); + key_check(key); + + ret = __key_link_begin(keyring, &key->index_key, &edit); + if (ret == 0) { + kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage)); + ret = __key_link_check_restriction(keyring, key); + if (ret == 0) + ret = __key_link_check_live_key(keyring, key); + if (ret == 0) + __key_link(key, &edit); + __key_link_end(keyring, &key->index_key, edit); + } + + kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage)); + return ret; +} +EXPORT_SYMBOL(key_link); + +/** + * key_unlink - Unlink the first link to a key from a keyring. + * @keyring: The keyring to remove the link from. + * @key: The key the link is to. + * + * Remove a link from a keyring to a key. + * + * This function will write-lock the keyring's semaphore. + * + * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if + * the key isn't linked to by the keyring or -ENOMEM if there's insufficient + * memory. + * + * It is assumed that the caller has checked that it is permitted for a link to + * be removed (the keyring should have Write permission; no permissions are + * required on the key). + */ +int key_unlink(struct key *keyring, struct key *key) +{ + struct assoc_array_edit *edit; + int ret; + + key_check(keyring); + key_check(key); + + if (keyring->type != &key_type_keyring) + return -ENOTDIR; + + down_write(&keyring->sem); + + edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, + &key->index_key); + if (IS_ERR(edit)) { + ret = PTR_ERR(edit); + goto error; + } + ret = -ENOENT; + if (edit == NULL) + goto error; + + assoc_array_apply_edit(edit); + key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); + ret = 0; + +error: + up_write(&keyring->sem); + return ret; +} +EXPORT_SYMBOL(key_unlink); + +/** + * keyring_clear - Clear a keyring + * @keyring: The keyring to clear. + * + * Clear the contents of the specified keyring. + * + * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. + */ +int keyring_clear(struct key *keyring) +{ + struct assoc_array_edit *edit; + int ret; + + if (keyring->type != &key_type_keyring) + return -ENOTDIR; + + down_write(&keyring->sem); + + edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); + if (IS_ERR(edit)) { + ret = PTR_ERR(edit); + } else { + if (edit) + assoc_array_apply_edit(edit); + key_payload_reserve(keyring, 0); + ret = 0; + } + + up_write(&keyring->sem); + return ret; +} +EXPORT_SYMBOL(keyring_clear); + +/* + * Dispose of the links from a revoked keyring. + * + * This is called with the key sem write-locked. + */ +static void keyring_revoke(struct key *keyring) +{ + struct assoc_array_edit *edit; + + edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); + if (!IS_ERR(edit)) { + if (edit) + assoc_array_apply_edit(edit); + key_payload_reserve(keyring, 0); + } +} + +static bool keyring_gc_select_iterator(void *object, void *iterator_data) +{ + struct key *key = keyring_ptr_to_key(object); + time64_t *limit = iterator_data; + + if (key_is_dead(key, *limit)) + return false; + key_get(key); + return true; +} + +static int keyring_gc_check_iterator(const void *object, void *iterator_data) +{ + const struct key *key = keyring_ptr_to_key(object); + time64_t *limit = iterator_data; + + key_check(key); + return key_is_dead(key, *limit); +} + +/* + * Garbage collect pointers from a keyring. + * + * Not called with any locks held. The keyring's key struct will not be + * deallocated under us as only our caller may deallocate it. + */ +void keyring_gc(struct key *keyring, time64_t limit) +{ + int result; + + kenter("%x{%s}", keyring->serial, keyring->description ?: ""); + + if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) + goto dont_gc; + + /* scan the keyring looking for dead keys */ + rcu_read_lock(); + result = assoc_array_iterate(&keyring->keys, + keyring_gc_check_iterator, &limit); + rcu_read_unlock(); + if (result == true) + goto do_gc; + +dont_gc: + kleave(" [no gc]"); + return; + +do_gc: + down_write(&keyring->sem); + assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, + keyring_gc_select_iterator, &limit); + up_write(&keyring->sem); + kleave(" [gc]"); +} + +/* + * Garbage collect restriction pointers from a keyring. + * + * Keyring restrictions are associated with a key type, and must be cleaned + * up if the key type is unregistered. The restriction is altered to always + * reject additional keys so a keyring cannot be opened up by unregistering + * a key type. + * + * Not called with any keyring locks held. The keyring's key struct will not + * be deallocated under us as only our caller may deallocate it. + * + * The caller is required to hold key_types_sem and dead_type->sem. This is + * fulfilled by key_gc_keytype() holding the locks on behalf of + * key_garbage_collector(), which it invokes on a workqueue. + */ +void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type) +{ + struct key_restriction *keyres; + + kenter("%x{%s}", keyring->serial, keyring->description ?: ""); + + /* + * keyring->restrict_link is only assigned at key allocation time + * or with the key type locked, so the only values that could be + * concurrently assigned to keyring->restrict_link are for key + * types other than dead_type. Given this, it's ok to check + * the key type before acquiring keyring->sem. + */ + if (!dead_type || !keyring->restrict_link || + keyring->restrict_link->keytype != dead_type) { + kleave(" [no restriction gc]"); + return; + } + + /* Lock the keyring to ensure that a link is not in progress */ + down_write(&keyring->sem); + + keyres = keyring->restrict_link; + + keyres->check = restrict_link_reject; + + key_put(keyres->key); + keyres->key = NULL; + keyres->keytype = NULL; + + up_write(&keyring->sem); + + kleave(" [restriction gc]"); +} diff --git a/security/keys/permission.c b/security/keys/permission.c new file mode 100644 index 000000000..f68dc04d6 --- /dev/null +++ b/security/keys/permission.c @@ -0,0 +1,110 @@ +/* Key permission checking + * + * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/security.h> +#include "internal.h" + +/** + * key_task_permission - Check a key can be used + * @key_ref: The key to check. + * @cred: The credentials to use. + * @perm: The permissions to check for. + * + * Check to see whether permission is granted to use a key in the desired way, + * but permit the security modules to override. + * + * The caller must hold either a ref on cred or must hold the RCU readlock. + * + * Returns 0 if successful, -EACCES if access is denied based on the + * permissions bits or the LSM check. + */ +int key_task_permission(const key_ref_t key_ref, const struct cred *cred, + unsigned perm) +{ + struct key *key; + key_perm_t kperm; + int ret; + + key = key_ref_to_ptr(key_ref); + + /* use the second 8-bits of permissions for keys the caller owns */ + if (uid_eq(key->uid, cred->fsuid)) { + kperm = key->perm >> 16; + goto use_these_perms; + } + + /* use the third 8-bits of permissions for keys the caller has a group + * membership in common with */ + if (gid_valid(key->gid) && key->perm & KEY_GRP_ALL) { + if (gid_eq(key->gid, cred->fsgid)) { + kperm = key->perm >> 8; + goto use_these_perms; + } + + ret = groups_search(cred->group_info, key->gid); + if (ret) { + kperm = key->perm >> 8; + goto use_these_perms; + } + } + + /* otherwise use the least-significant 8-bits */ + kperm = key->perm; + +use_these_perms: + + /* use the top 8-bits of permissions for keys the caller possesses + * - possessor permissions are additive with other permissions + */ + if (is_key_possessed(key_ref)) + kperm |= key->perm >> 24; + + kperm = kperm & perm & KEY_NEED_ALL; + + if (kperm != perm) + return -EACCES; + + /* let LSM be the final arbiter */ + return security_key_permission(key_ref, cred, perm); +} +EXPORT_SYMBOL(key_task_permission); + +/** + * key_validate - Validate a key. + * @key: The key to be validated. + * + * Check that a key is valid, returning 0 if the key is okay, -ENOKEY if the + * key is invalidated, -EKEYREVOKED if the key's type has been removed or if + * the key has been revoked or -EKEYEXPIRED if the key has expired. + */ +int key_validate(const struct key *key) +{ + unsigned long flags = READ_ONCE(key->flags); + time64_t expiry = READ_ONCE(key->expiry); + + if (flags & (1 << KEY_FLAG_INVALIDATED)) + return -ENOKEY; + + /* check it's still accessible */ + if (flags & ((1 << KEY_FLAG_REVOKED) | + (1 << KEY_FLAG_DEAD))) + return -EKEYREVOKED; + + /* check it hasn't expired */ + if (expiry) { + if (ktime_get_real_seconds() >= expiry) + return -EKEYEXPIRED; + } + + return 0; +} +EXPORT_SYMBOL(key_validate); diff --git a/security/keys/persistent.c b/security/keys/persistent.c new file mode 100644 index 000000000..d0cb5b32e --- /dev/null +++ b/security/keys/persistent.c @@ -0,0 +1,169 @@ +/* General persistent per-UID keyrings register + * + * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/user_namespace.h> +#include <linux/cred.h> + +#include "internal.h" + +unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */ + +/* + * Create the persistent keyring register for the current user namespace. + * + * Called with the namespace's sem locked for writing. + */ +static int key_create_persistent_register(struct user_namespace *ns) +{ + struct key *reg = keyring_alloc(".persistent_register", + KUIDT_INIT(0), KGIDT_INIT(0), + current_cred(), + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | + KEY_USR_VIEW | KEY_USR_READ), + KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); + if (IS_ERR(reg)) + return PTR_ERR(reg); + + ns->persistent_keyring_register = reg; + return 0; +} + +/* + * Create the persistent keyring for the specified user. + * + * Called with the namespace's sem locked for writing. + */ +static key_ref_t key_create_persistent(struct user_namespace *ns, kuid_t uid, + struct keyring_index_key *index_key) +{ + struct key *persistent; + key_ref_t reg_ref, persistent_ref; + + if (!ns->persistent_keyring_register) { + long err = key_create_persistent_register(ns); + if (err < 0) + return ERR_PTR(err); + } else { + reg_ref = make_key_ref(ns->persistent_keyring_register, true); + persistent_ref = find_key_to_update(reg_ref, index_key); + if (persistent_ref) + return persistent_ref; + } + + persistent = keyring_alloc(index_key->description, + uid, INVALID_GID, current_cred(), + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | + KEY_USR_VIEW | KEY_USR_READ), + KEY_ALLOC_NOT_IN_QUOTA, NULL, + ns->persistent_keyring_register); + if (IS_ERR(persistent)) + return ERR_CAST(persistent); + + return make_key_ref(persistent, true); +} + +/* + * Get the persistent keyring for a specific UID and link it to the nominated + * keyring. + */ +static long key_get_persistent(struct user_namespace *ns, kuid_t uid, + key_ref_t dest_ref) +{ + struct keyring_index_key index_key; + struct key *persistent; + key_ref_t reg_ref, persistent_ref; + char buf[32]; + long ret; + + /* Look in the register if it exists */ + index_key.type = &key_type_keyring; + index_key.description = buf; + index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid)); + + if (ns->persistent_keyring_register) { + reg_ref = make_key_ref(ns->persistent_keyring_register, true); + down_read(&ns->persistent_keyring_register_sem); + persistent_ref = find_key_to_update(reg_ref, &index_key); + up_read(&ns->persistent_keyring_register_sem); + + if (persistent_ref) + goto found; + } + + /* It wasn't in the register, so we'll need to create it. We might + * also need to create the register. + */ + down_write(&ns->persistent_keyring_register_sem); + persistent_ref = key_create_persistent(ns, uid, &index_key); + up_write(&ns->persistent_keyring_register_sem); + if (!IS_ERR(persistent_ref)) + goto found; + + return PTR_ERR(persistent_ref); + +found: + ret = key_task_permission(persistent_ref, current_cred(), KEY_NEED_LINK); + if (ret == 0) { + persistent = key_ref_to_ptr(persistent_ref); + ret = key_link(key_ref_to_ptr(dest_ref), persistent); + if (ret == 0) { + key_set_timeout(persistent, persistent_keyring_expiry); + ret = persistent->serial; + } + } + + key_ref_put(persistent_ref); + return ret; +} + +/* + * Get the persistent keyring for a specific UID and link it to the nominated + * keyring. + */ +long keyctl_get_persistent(uid_t _uid, key_serial_t destid) +{ + struct user_namespace *ns = current_user_ns(); + key_ref_t dest_ref; + kuid_t uid; + long ret; + + /* -1 indicates the current user */ + if (_uid == (uid_t)-1) { + uid = current_uid(); + } else { + uid = make_kuid(ns, _uid); + if (!uid_valid(uid)) + return -EINVAL; + + /* You can only see your own persistent cache if you're not + * sufficiently privileged. + */ + if (!uid_eq(uid, current_uid()) && + !uid_eq(uid, current_euid()) && + !ns_capable(ns, CAP_SETUID)) + return -EPERM; + } + + /* There must be a destination keyring */ + dest_ref = lookup_user_key(destid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); + if (IS_ERR(dest_ref)) + return PTR_ERR(dest_ref); + if (key_ref_to_ptr(dest_ref)->type != &key_type_keyring) { + ret = -ENOTDIR; + goto out_put_dest; + } + + ret = key_get_persistent(ns, uid, dest_ref); + +out_put_dest: + key_ref_put(dest_ref); + return ret; +} diff --git a/security/keys/proc.c b/security/keys/proc.c new file mode 100644 index 000000000..7ec2779cb --- /dev/null +++ b/security/keys/proc.c @@ -0,0 +1,325 @@ +/* procfs files for key database enumeration + * + * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <asm/errno.h> +#include "internal.h" + +static void *proc_keys_start(struct seq_file *p, loff_t *_pos); +static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos); +static void proc_keys_stop(struct seq_file *p, void *v); +static int proc_keys_show(struct seq_file *m, void *v); + +static const struct seq_operations proc_keys_ops = { + .start = proc_keys_start, + .next = proc_keys_next, + .stop = proc_keys_stop, + .show = proc_keys_show, +}; + +static void *proc_key_users_start(struct seq_file *p, loff_t *_pos); +static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos); +static void proc_key_users_stop(struct seq_file *p, void *v); +static int proc_key_users_show(struct seq_file *m, void *v); + +static const struct seq_operations proc_key_users_ops = { + .start = proc_key_users_start, + .next = proc_key_users_next, + .stop = proc_key_users_stop, + .show = proc_key_users_show, +}; + +/* + * Declare the /proc files. + */ +static int __init key_proc_init(void) +{ + struct proc_dir_entry *p; + + p = proc_create_seq("keys", 0, NULL, &proc_keys_ops); + if (!p) + panic("Cannot create /proc/keys\n"); + + p = proc_create_seq("key-users", 0, NULL, &proc_key_users_ops); + if (!p) + panic("Cannot create /proc/key-users\n"); + + return 0; +} + +__initcall(key_proc_init); + +/* + * Implement "/proc/keys" to provide a list of the keys on the system that + * grant View permission to the caller. + */ +static struct rb_node *key_serial_next(struct seq_file *p, struct rb_node *n) +{ + struct user_namespace *user_ns = seq_user_ns(p); + + n = rb_next(n); + while (n) { + struct key *key = rb_entry(n, struct key, serial_node); + if (kuid_has_mapping(user_ns, key->user->uid)) + break; + n = rb_next(n); + } + return n; +} + +static struct key *find_ge_key(struct seq_file *p, key_serial_t id) +{ + struct user_namespace *user_ns = seq_user_ns(p); + struct rb_node *n = key_serial_tree.rb_node; + struct key *minkey = NULL; + + while (n) { + struct key *key = rb_entry(n, struct key, serial_node); + if (id < key->serial) { + if (!minkey || minkey->serial > key->serial) + minkey = key; + n = n->rb_left; + } else if (id > key->serial) { + n = n->rb_right; + } else { + minkey = key; + break; + } + key = NULL; + } + + if (!minkey) + return NULL; + + for (;;) { + if (kuid_has_mapping(user_ns, minkey->user->uid)) + return minkey; + n = rb_next(&minkey->serial_node); + if (!n) + return NULL; + minkey = rb_entry(n, struct key, serial_node); + } +} + +static void *proc_keys_start(struct seq_file *p, loff_t *_pos) + __acquires(key_serial_lock) +{ + key_serial_t pos = *_pos; + struct key *key; + + spin_lock(&key_serial_lock); + + if (*_pos > INT_MAX) + return NULL; + key = find_ge_key(p, pos); + if (!key) + return NULL; + *_pos = key->serial; + return &key->serial_node; +} + +static inline key_serial_t key_node_serial(struct rb_node *n) +{ + struct key *key = rb_entry(n, struct key, serial_node); + return key->serial; +} + +static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos) +{ + struct rb_node *n; + + n = key_serial_next(p, v); + if (n) + *_pos = key_node_serial(n); + else + (*_pos)++; + return n; +} + +static void proc_keys_stop(struct seq_file *p, void *v) + __releases(key_serial_lock) +{ + spin_unlock(&key_serial_lock); +} + +static int proc_keys_show(struct seq_file *m, void *v) +{ + struct rb_node *_p = v; + struct key *key = rb_entry(_p, struct key, serial_node); + unsigned long flags; + key_ref_t key_ref, skey_ref; + time64_t now, expiry; + char xbuf[16]; + short state; + u64 timo; + int rc; + + struct keyring_search_context ctx = { + .index_key = key->index_key, + .cred = m->file->f_cred, + .match_data.cmp = lookup_user_key_possessed, + .match_data.raw_data = key, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = KEYRING_SEARCH_NO_STATE_CHECK, + }; + + key_ref = make_key_ref(key, 0); + + /* determine if the key is possessed by this process (a test we can + * skip if the key does not indicate the possessor can view it + */ + if (key->perm & KEY_POS_VIEW) { + skey_ref = search_my_process_keyrings(&ctx); + if (!IS_ERR(skey_ref)) { + key_ref_put(skey_ref); + key_ref = make_key_ref(key, 1); + } + } + + /* check whether the current task is allowed to view the key */ + rc = key_task_permission(key_ref, ctx.cred, KEY_NEED_VIEW); + if (rc < 0) + return 0; + + now = ktime_get_real_seconds(); + + rcu_read_lock(); + + /* come up with a suitable timeout value */ + expiry = READ_ONCE(key->expiry); + if (expiry == 0) { + memcpy(xbuf, "perm", 5); + } else if (now >= expiry) { + memcpy(xbuf, "expd", 5); + } else { + timo = expiry - now; + + if (timo < 60) + sprintf(xbuf, "%llus", timo); + else if (timo < 60*60) + sprintf(xbuf, "%llum", div_u64(timo, 60)); + else if (timo < 60*60*24) + sprintf(xbuf, "%lluh", div_u64(timo, 60 * 60)); + else if (timo < 60*60*24*7) + sprintf(xbuf, "%llud", div_u64(timo, 60 * 60 * 24)); + else + sprintf(xbuf, "%lluw", div_u64(timo, 60 * 60 * 24 * 7)); + } + + state = key_read_state(key); + +#define showflag(FLAGS, LETTER, FLAG) \ + ((FLAGS & (1 << FLAG)) ? LETTER : '-') + + flags = READ_ONCE(key->flags); + seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ", + key->serial, + state != KEY_IS_UNINSTANTIATED ? 'I' : '-', + showflag(flags, 'R', KEY_FLAG_REVOKED), + showflag(flags, 'D', KEY_FLAG_DEAD), + showflag(flags, 'Q', KEY_FLAG_IN_QUOTA), + showflag(flags, 'U', KEY_FLAG_USER_CONSTRUCT), + state < 0 ? 'N' : '-', + showflag(flags, 'i', KEY_FLAG_INVALIDATED), + refcount_read(&key->usage), + xbuf, + key->perm, + from_kuid_munged(seq_user_ns(m), key->uid), + from_kgid_munged(seq_user_ns(m), key->gid), + key->type->name); + +#undef showflag + + if (key->type->describe) + key->type->describe(key, m); + seq_putc(m, '\n'); + + rcu_read_unlock(); + return 0; +} + +static struct rb_node *__key_user_next(struct user_namespace *user_ns, struct rb_node *n) +{ + while (n) { + struct key_user *user = rb_entry(n, struct key_user, node); + if (kuid_has_mapping(user_ns, user->uid)) + break; + n = rb_next(n); + } + return n; +} + +static struct rb_node *key_user_next(struct user_namespace *user_ns, struct rb_node *n) +{ + return __key_user_next(user_ns, rb_next(n)); +} + +static struct rb_node *key_user_first(struct user_namespace *user_ns, struct rb_root *r) +{ + struct rb_node *n = rb_first(r); + return __key_user_next(user_ns, n); +} + +static void *proc_key_users_start(struct seq_file *p, loff_t *_pos) + __acquires(key_user_lock) +{ + struct rb_node *_p; + loff_t pos = *_pos; + + spin_lock(&key_user_lock); + + _p = key_user_first(seq_user_ns(p), &key_user_tree); + while (pos > 0 && _p) { + pos--; + _p = key_user_next(seq_user_ns(p), _p); + } + + return _p; +} + +static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos) +{ + (*_pos)++; + return key_user_next(seq_user_ns(p), (struct rb_node *)v); +} + +static void proc_key_users_stop(struct seq_file *p, void *v) + __releases(key_user_lock) +{ + spin_unlock(&key_user_lock); +} + +static int proc_key_users_show(struct seq_file *m, void *v) +{ + struct rb_node *_p = v; + struct key_user *user = rb_entry(_p, struct key_user, node); + unsigned maxkeys = uid_eq(user->uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxkeys : key_quota_maxkeys; + unsigned maxbytes = uid_eq(user->uid, GLOBAL_ROOT_UID) ? + key_quota_root_maxbytes : key_quota_maxbytes; + + seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n", + from_kuid_munged(seq_user_ns(m), user->uid), + refcount_read(&user->usage), + atomic_read(&user->nkeys), + atomic_read(&user->nikeys), + user->qnkeys, + maxkeys, + user->qnbytes, + maxbytes); + + return 0; +} diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c new file mode 100644 index 000000000..d776d2114 --- /dev/null +++ b/security/keys/process_keys.c @@ -0,0 +1,891 @@ +/* Manage a process's keyrings + * + * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/sched/user.h> +#include <linux/keyctl.h> +#include <linux/fs.h> +#include <linux/err.h> +#include <linux/mutex.h> +#include <linux/security.h> +#include <linux/user_namespace.h> +#include <linux/uaccess.h> +#include <keys/request_key_auth-type.h> +#include "internal.h" + +/* Session keyring create vs join semaphore */ +static DEFINE_MUTEX(key_session_mutex); + +/* User keyring creation semaphore */ +static DEFINE_MUTEX(key_user_keyring_mutex); + +/* The root user's tracking struct */ +struct key_user root_key_user = { + .usage = REFCOUNT_INIT(3), + .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock), + .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock), + .nkeys = ATOMIC_INIT(2), + .nikeys = ATOMIC_INIT(2), + .uid = GLOBAL_ROOT_UID, +}; + +/* + * Install the user and user session keyrings for the current process's UID. + */ +int install_user_keyrings(void) +{ + struct user_struct *user; + const struct cred *cred; + struct key *uid_keyring, *session_keyring; + key_perm_t user_keyring_perm; + char buf[20]; + int ret; + uid_t uid; + + user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL; + cred = current_cred(); + user = cred->user; + uid = from_kuid(cred->user_ns, user->uid); + + kenter("%p{%u}", user, uid); + + if (user->uid_keyring && user->session_keyring) { + kleave(" = 0 [exist]"); + return 0; + } + + mutex_lock(&key_user_keyring_mutex); + ret = 0; + + if (!user->uid_keyring) { + /* get the UID-specific keyring + * - there may be one in existence already as it may have been + * pinned by a session, but the user_struct pointing to it + * may have been destroyed by setuid */ + sprintf(buf, "_uid.%u", uid); + + uid_keyring = find_keyring_by_name(buf, true); + if (IS_ERR(uid_keyring)) { + uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID, + cred, user_keyring_perm, + KEY_ALLOC_UID_KEYRING | + KEY_ALLOC_IN_QUOTA, + NULL, NULL); + if (IS_ERR(uid_keyring)) { + ret = PTR_ERR(uid_keyring); + goto error; + } + } + + /* get a default session keyring (which might also exist + * already) */ + sprintf(buf, "_uid_ses.%u", uid); + + session_keyring = find_keyring_by_name(buf, true); + if (IS_ERR(session_keyring)) { + session_keyring = + keyring_alloc(buf, user->uid, INVALID_GID, + cred, user_keyring_perm, + KEY_ALLOC_UID_KEYRING | + KEY_ALLOC_IN_QUOTA, + NULL, NULL); + if (IS_ERR(session_keyring)) { + ret = PTR_ERR(session_keyring); + goto error_release; + } + + /* we install a link from the user session keyring to + * the user keyring */ + ret = key_link(session_keyring, uid_keyring); + if (ret < 0) + goto error_release_both; + } + + /* install the keyrings */ + user->uid_keyring = uid_keyring; + user->session_keyring = session_keyring; + } + + mutex_unlock(&key_user_keyring_mutex); + kleave(" = 0"); + return 0; + +error_release_both: + key_put(session_keyring); +error_release: + key_put(uid_keyring); +error: + mutex_unlock(&key_user_keyring_mutex); + kleave(" = %d", ret); + return ret; +} + +/* + * Install a thread keyring to the given credentials struct if it didn't have + * one already. This is allowed to overrun the quota. + * + * Return: 0 if a thread keyring is now present; -errno on failure. + */ +int install_thread_keyring_to_cred(struct cred *new) +{ + struct key *keyring; + + if (new->thread_keyring) + return 0; + + keyring = keyring_alloc("_tid", new->uid, new->gid, new, + KEY_POS_ALL | KEY_USR_VIEW, + KEY_ALLOC_QUOTA_OVERRUN, + NULL, NULL); + if (IS_ERR(keyring)) + return PTR_ERR(keyring); + + new->thread_keyring = keyring; + return 0; +} + +/* + * Install a thread keyring to the current task if it didn't have one already. + * + * Return: 0 if a thread keyring is now present; -errno on failure. + */ +static int install_thread_keyring(void) +{ + struct cred *new; + int ret; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + + ret = install_thread_keyring_to_cred(new); + if (ret < 0) { + abort_creds(new); + return ret; + } + + return commit_creds(new); +} + +/* + * Install a process keyring to the given credentials struct if it didn't have + * one already. This is allowed to overrun the quota. + * + * Return: 0 if a process keyring is now present; -errno on failure. + */ +int install_process_keyring_to_cred(struct cred *new) +{ + struct key *keyring; + + if (new->process_keyring) + return 0; + + keyring = keyring_alloc("_pid", new->uid, new->gid, new, + KEY_POS_ALL | KEY_USR_VIEW, + KEY_ALLOC_QUOTA_OVERRUN, + NULL, NULL); + if (IS_ERR(keyring)) + return PTR_ERR(keyring); + + new->process_keyring = keyring; + return 0; +} + +/* + * Install a process keyring to the current task if it didn't have one already. + * + * Return: 0 if a process keyring is now present; -errno on failure. + */ +static int install_process_keyring(void) +{ + struct cred *new; + int ret; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + + ret = install_process_keyring_to_cred(new); + if (ret < 0) { + abort_creds(new); + return ret; + } + + return commit_creds(new); +} + +/* + * Install the given keyring as the session keyring of the given credentials + * struct, replacing the existing one if any. If the given keyring is NULL, + * then install a new anonymous session keyring. + * + * Return: 0 on success; -errno on failure. + */ +int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) +{ + unsigned long flags; + struct key *old; + + might_sleep(); + + /* create an empty session keyring */ + if (!keyring) { + flags = KEY_ALLOC_QUOTA_OVERRUN; + if (cred->session_keyring) + flags = KEY_ALLOC_IN_QUOTA; + + keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred, + KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, + flags, NULL, NULL); + if (IS_ERR(keyring)) + return PTR_ERR(keyring); + } else { + __key_get(keyring); + } + + /* install the keyring */ + old = cred->session_keyring; + rcu_assign_pointer(cred->session_keyring, keyring); + + if (old) + key_put(old); + + return 0; +} + +/* + * Install the given keyring as the session keyring of the current task, + * replacing the existing one if any. If the given keyring is NULL, then + * install a new anonymous session keyring. + * + * Return: 0 on success; -errno on failure. + */ +static int install_session_keyring(struct key *keyring) +{ + struct cred *new; + int ret; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + + ret = install_session_keyring_to_cred(new, keyring); + if (ret < 0) { + abort_creds(new); + return ret; + } + + return commit_creds(new); +} + +/* + * Handle the fsuid changing. + */ +void key_fsuid_changed(struct task_struct *tsk) +{ + /* update the ownership of the thread keyring */ + BUG_ON(!tsk->cred); + if (tsk->cred->thread_keyring) { + down_write(&tsk->cred->thread_keyring->sem); + tsk->cred->thread_keyring->uid = tsk->cred->fsuid; + up_write(&tsk->cred->thread_keyring->sem); + } +} + +/* + * Handle the fsgid changing. + */ +void key_fsgid_changed(struct task_struct *tsk) +{ + /* update the ownership of the thread keyring */ + BUG_ON(!tsk->cred); + if (tsk->cred->thread_keyring) { + down_write(&tsk->cred->thread_keyring->sem); + tsk->cred->thread_keyring->gid = tsk->cred->fsgid; + up_write(&tsk->cred->thread_keyring->sem); + } +} + +/* + * Search the process keyrings attached to the supplied cred for the first + * matching key. + * + * The search criteria are the type and the match function. The description is + * given to the match function as a parameter, but doesn't otherwise influence + * the search. Typically the match function will compare the description + * parameter to the key's description. + * + * This can only search keyrings that grant Search permission to the supplied + * credentials. Keyrings linked to searched keyrings will also be searched if + * they grant Search permission too. Keys can only be found if they grant + * Search permission to the credentials. + * + * Returns a pointer to the key with the key usage count incremented if + * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only + * matched negative keys. + * + * In the case of a successful return, the possession attribute is set on the + * returned key reference. + */ +key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx) +{ + key_ref_t key_ref, ret, err; + + /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were + * searchable, but we failed to find a key or we found a negative key; + * otherwise we want to return a sample error (probably -EACCES) if + * none of the keyrings were searchable + * + * in terms of priority: success > -ENOKEY > -EAGAIN > other error + */ + key_ref = NULL; + ret = NULL; + err = ERR_PTR(-EAGAIN); + + /* search the thread keyring first */ + if (ctx->cred->thread_keyring) { + key_ref = keyring_search_aux( + make_key_ref(ctx->cred->thread_keyring, 1), ctx); + if (!IS_ERR(key_ref)) + goto found; + + switch (PTR_ERR(key_ref)) { + case -EAGAIN: /* no key */ + case -ENOKEY: /* negative key */ + ret = key_ref; + break; + default: + err = key_ref; + break; + } + } + + /* search the process keyring second */ + if (ctx->cred->process_keyring) { + key_ref = keyring_search_aux( + make_key_ref(ctx->cred->process_keyring, 1), ctx); + if (!IS_ERR(key_ref)) + goto found; + + switch (PTR_ERR(key_ref)) { + case -EAGAIN: /* no key */ + if (ret) + break; + case -ENOKEY: /* negative key */ + ret = key_ref; + break; + default: + err = key_ref; + break; + } + } + + /* search the session keyring */ + if (ctx->cred->session_keyring) { + rcu_read_lock(); + key_ref = keyring_search_aux( + make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1), + ctx); + rcu_read_unlock(); + + if (!IS_ERR(key_ref)) + goto found; + + switch (PTR_ERR(key_ref)) { + case -EAGAIN: /* no key */ + if (ret) + break; + case -ENOKEY: /* negative key */ + ret = key_ref; + break; + default: + err = key_ref; + break; + } + } + /* or search the user-session keyring */ + else if (ctx->cred->user->session_keyring) { + key_ref = keyring_search_aux( + make_key_ref(ctx->cred->user->session_keyring, 1), + ctx); + if (!IS_ERR(key_ref)) + goto found; + + switch (PTR_ERR(key_ref)) { + case -EAGAIN: /* no key */ + if (ret) + break; + case -ENOKEY: /* negative key */ + ret = key_ref; + break; + default: + err = key_ref; + break; + } + } + + /* no key - decide on the error we're going to go for */ + key_ref = ret ? ret : err; + +found: + return key_ref; +} + +/* + * Search the process keyrings attached to the supplied cred for the first + * matching key in the manner of search_my_process_keyrings(), but also search + * the keys attached to the assumed authorisation key using its credentials if + * one is available. + * + * Return same as search_my_process_keyrings(). + */ +key_ref_t search_process_keyrings(struct keyring_search_context *ctx) +{ + struct request_key_auth *rka; + key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; + + might_sleep(); + + key_ref = search_my_process_keyrings(ctx); + if (!IS_ERR(key_ref)) + goto found; + err = key_ref; + + /* if this process has an instantiation authorisation key, then we also + * search the keyrings of the process mentioned there + * - we don't permit access to request_key auth keys via this method + */ + if (ctx->cred->request_key_auth && + ctx->cred == current_cred() && + ctx->index_key.type != &key_type_request_key_auth + ) { + const struct cred *cred = ctx->cred; + + /* defend against the auth key being revoked */ + down_read(&cred->request_key_auth->sem); + + if (key_validate(ctx->cred->request_key_auth) == 0) { + rka = ctx->cred->request_key_auth->payload.data[0]; + + ctx->cred = rka->cred; + key_ref = search_process_keyrings(ctx); + ctx->cred = cred; + + up_read(&cred->request_key_auth->sem); + + if (!IS_ERR(key_ref)) + goto found; + + ret = key_ref; + } else { + up_read(&cred->request_key_auth->sem); + } + } + + /* no key - decide on the error we're going to go for */ + if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) + key_ref = ERR_PTR(-ENOKEY); + else if (err == ERR_PTR(-EACCES)) + key_ref = ret; + else + key_ref = err; + +found: + return key_ref; +} + +/* + * See if the key we're looking at is the target key. + */ +bool lookup_user_key_possessed(const struct key *key, + const struct key_match_data *match_data) +{ + return key == match_data->raw_data; +} + +/* + * Look up a key ID given us by userspace with a given permissions mask to get + * the key it refers to. + * + * Flags can be passed to request that special keyrings be created if referred + * to directly, to permit partially constructed keys to be found and to skip + * validity and permission checks on the found key. + * + * Returns a pointer to the key with an incremented usage count if successful; + * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond + * to a key or the best found key was a negative key; -EKEYREVOKED or + * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the + * found key doesn't grant the requested permit or the LSM denied access to it; + * or -ENOMEM if a special keyring couldn't be created. + * + * In the case of a successful return, the possession attribute is set on the + * returned key reference. + */ +key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, + key_perm_t perm) +{ + struct keyring_search_context ctx = { + .match_data.cmp = lookup_user_key_possessed, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = KEYRING_SEARCH_NO_STATE_CHECK, + }; + struct request_key_auth *rka; + struct key *key; + key_ref_t key_ref, skey_ref; + int ret; + +try_again: + ctx.cred = get_current_cred(); + key_ref = ERR_PTR(-ENOKEY); + + switch (id) { + case KEY_SPEC_THREAD_KEYRING: + if (!ctx.cred->thread_keyring) { + if (!(lflags & KEY_LOOKUP_CREATE)) + goto error; + + ret = install_thread_keyring(); + if (ret < 0) { + key_ref = ERR_PTR(ret); + goto error; + } + goto reget_creds; + } + + key = ctx.cred->thread_keyring; + __key_get(key); + key_ref = make_key_ref(key, 1); + break; + + case KEY_SPEC_PROCESS_KEYRING: + if (!ctx.cred->process_keyring) { + if (!(lflags & KEY_LOOKUP_CREATE)) + goto error; + + ret = install_process_keyring(); + if (ret < 0) { + key_ref = ERR_PTR(ret); + goto error; + } + goto reget_creds; + } + + key = ctx.cred->process_keyring; + __key_get(key); + key_ref = make_key_ref(key, 1); + break; + + case KEY_SPEC_SESSION_KEYRING: + if (!ctx.cred->session_keyring) { + /* always install a session keyring upon access if one + * doesn't exist yet */ + ret = install_user_keyrings(); + if (ret < 0) + goto error; + if (lflags & KEY_LOOKUP_CREATE) + ret = join_session_keyring(NULL); + else + ret = install_session_keyring( + ctx.cred->user->session_keyring); + + if (ret < 0) + goto error; + goto reget_creds; + } else if (ctx.cred->session_keyring == + ctx.cred->user->session_keyring && + lflags & KEY_LOOKUP_CREATE) { + ret = join_session_keyring(NULL); + if (ret < 0) + goto error; + goto reget_creds; + } + + rcu_read_lock(); + key = rcu_dereference(ctx.cred->session_keyring); + __key_get(key); + rcu_read_unlock(); + key_ref = make_key_ref(key, 1); + break; + + case KEY_SPEC_USER_KEYRING: + if (!ctx.cred->user->uid_keyring) { + ret = install_user_keyrings(); + if (ret < 0) + goto error; + } + + key = ctx.cred->user->uid_keyring; + __key_get(key); + key_ref = make_key_ref(key, 1); + break; + + case KEY_SPEC_USER_SESSION_KEYRING: + if (!ctx.cred->user->session_keyring) { + ret = install_user_keyrings(); + if (ret < 0) + goto error; + } + + key = ctx.cred->user->session_keyring; + __key_get(key); + key_ref = make_key_ref(key, 1); + break; + + case KEY_SPEC_GROUP_KEYRING: + /* group keyrings are not yet supported */ + key_ref = ERR_PTR(-EINVAL); + goto error; + + case KEY_SPEC_REQKEY_AUTH_KEY: + key = ctx.cred->request_key_auth; + if (!key) + goto error; + + __key_get(key); + key_ref = make_key_ref(key, 1); + break; + + case KEY_SPEC_REQUESTOR_KEYRING: + if (!ctx.cred->request_key_auth) + goto error; + + down_read(&ctx.cred->request_key_auth->sem); + if (test_bit(KEY_FLAG_REVOKED, + &ctx.cred->request_key_auth->flags)) { + key_ref = ERR_PTR(-EKEYREVOKED); + key = NULL; + } else { + rka = ctx.cred->request_key_auth->payload.data[0]; + key = rka->dest_keyring; + __key_get(key); + } + up_read(&ctx.cred->request_key_auth->sem); + if (!key) + goto error; + key_ref = make_key_ref(key, 1); + break; + + default: + key_ref = ERR_PTR(-EINVAL); + if (id < 1) + goto error; + + key = key_lookup(id); + if (IS_ERR(key)) { + key_ref = ERR_CAST(key); + goto error; + } + + key_ref = make_key_ref(key, 0); + + /* check to see if we possess the key */ + ctx.index_key.type = key->type; + ctx.index_key.description = key->description; + ctx.index_key.desc_len = strlen(key->description); + ctx.match_data.raw_data = key; + kdebug("check possessed"); + skey_ref = search_process_keyrings(&ctx); + kdebug("possessed=%p", skey_ref); + + if (!IS_ERR(skey_ref)) { + key_put(key); + key_ref = skey_ref; + } + + break; + } + + /* unlink does not use the nominated key in any way, so can skip all + * the permission checks as it is only concerned with the keyring */ + if (lflags & KEY_LOOKUP_FOR_UNLINK) { + ret = 0; + goto error; + } + + if (!(lflags & KEY_LOOKUP_PARTIAL)) { + ret = wait_for_key_construction(key, true); + switch (ret) { + case -ERESTARTSYS: + goto invalid_key; + default: + if (perm) + goto invalid_key; + case 0: + break; + } + } else if (perm) { + ret = key_validate(key); + if (ret < 0) + goto invalid_key; + } + + ret = -EIO; + if (!(lflags & KEY_LOOKUP_PARTIAL) && + key_read_state(key) == KEY_IS_UNINSTANTIATED) + goto invalid_key; + + /* check the permissions */ + ret = key_task_permission(key_ref, ctx.cred, perm); + if (ret < 0) + goto invalid_key; + + key->last_used_at = ktime_get_real_seconds(); + +error: + put_cred(ctx.cred); + return key_ref; + +invalid_key: + key_ref_put(key_ref); + key_ref = ERR_PTR(ret); + goto error; + + /* if we attempted to install a keyring, then it may have caused new + * creds to be installed */ +reget_creds: + put_cred(ctx.cred); + goto try_again; +} + +/* + * Join the named keyring as the session keyring if possible else attempt to + * create a new one of that name and join that. + * + * If the name is NULL, an empty anonymous keyring will be installed as the + * session keyring. + * + * Named session keyrings are joined with a semaphore held to prevent the + * keyrings from going away whilst the attempt is made to going them and also + * to prevent a race in creating compatible session keyrings. + */ +long join_session_keyring(const char *name) +{ + const struct cred *old; + struct cred *new; + struct key *keyring; + long ret, serial; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + old = current_cred(); + + /* if no name is provided, install an anonymous keyring */ + if (!name) { + ret = install_session_keyring_to_cred(new, NULL); + if (ret < 0) + goto error; + + serial = new->session_keyring->serial; + ret = commit_creds(new); + if (ret == 0) + ret = serial; + goto okay; + } + + /* allow the user to join or create a named keyring */ + mutex_lock(&key_session_mutex); + + /* look for an existing keyring of this name */ + keyring = find_keyring_by_name(name, false); + if (PTR_ERR(keyring) == -ENOKEY) { + /* not found - try and create a new one */ + keyring = keyring_alloc( + name, old->uid, old->gid, old, + KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK, + KEY_ALLOC_IN_QUOTA, NULL, NULL); + if (IS_ERR(keyring)) { + ret = PTR_ERR(keyring); + goto error2; + } + } else if (IS_ERR(keyring)) { + ret = PTR_ERR(keyring); + goto error2; + } else if (keyring == new->session_keyring) { + ret = 0; + goto error3; + } + + /* we've got a keyring - now to install it */ + ret = install_session_keyring_to_cred(new, keyring); + if (ret < 0) + goto error3; + + commit_creds(new); + mutex_unlock(&key_session_mutex); + + ret = keyring->serial; + key_put(keyring); +okay: + return ret; + +error3: + key_put(keyring); +error2: + mutex_unlock(&key_session_mutex); +error: + abort_creds(new); + return ret; +} + +/* + * Replace a process's session keyring on behalf of one of its children when + * the target process is about to resume userspace execution. + */ +void key_change_session_keyring(struct callback_head *twork) +{ + const struct cred *old = current_cred(); + struct cred *new = container_of(twork, struct cred, rcu); + + if (unlikely(current->flags & PF_EXITING)) { + put_cred(new); + return; + } + + new-> uid = old-> uid; + new-> euid = old-> euid; + new-> suid = old-> suid; + new->fsuid = old->fsuid; + new-> gid = old-> gid; + new-> egid = old-> egid; + new-> sgid = old-> sgid; + new->fsgid = old->fsgid; + new->user = get_uid(old->user); + new->user_ns = get_user_ns(old->user_ns); + new->group_info = get_group_info(old->group_info); + + new->securebits = old->securebits; + new->cap_inheritable = old->cap_inheritable; + new->cap_permitted = old->cap_permitted; + new->cap_effective = old->cap_effective; + new->cap_ambient = old->cap_ambient; + new->cap_bset = old->cap_bset; + + new->jit_keyring = old->jit_keyring; + new->thread_keyring = key_get(old->thread_keyring); + new->process_keyring = key_get(old->process_keyring); + + security_transfer_creds(new, old); + + commit_creds(new); +} + +/* + * Make sure that root's user and user-session keyrings exist. + */ +static int __init init_root_keyring(void) +{ + return install_user_keyrings(); +} + +late_initcall(init_root_keyring); diff --git a/security/keys/request_key.c b/security/keys/request_key.c new file mode 100644 index 000000000..1a547cec8 --- /dev/null +++ b/security/keys/request_key.c @@ -0,0 +1,739 @@ +/* Request a key from userspace + * + * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * See Documentation/security/keys/request-key.rst + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/kmod.h> +#include <linux/err.h> +#include <linux/keyctl.h> +#include <linux/slab.h> +#include "internal.h" +#include <keys/request_key_auth-type.h> + +#define key_negative_timeout 60 /* default timeout on a negative key's existence */ + +/** + * complete_request_key - Complete the construction of a key. + * @auth_key: The authorisation key. + * @error: The success or failute of the construction. + * + * Complete the attempt to construct a key. The key will be negated + * if an error is indicated. The authorisation key will be revoked + * unconditionally. + */ +void complete_request_key(struct key *authkey, int error) +{ + struct request_key_auth *rka = get_request_key_auth(authkey); + struct key *key = rka->target_key; + + kenter("%d{%d},%d", authkey->serial, key->serial, error); + + if (error < 0) + key_negate_and_link(key, key_negative_timeout, NULL, authkey); + else + key_revoke(authkey); +} +EXPORT_SYMBOL(complete_request_key); + +/* + * Initialise a usermode helper that is going to have a specific session + * keyring. + * + * This is called in context of freshly forked kthread before kernel_execve(), + * so we can simply install the desired session_keyring at this point. + */ +static int umh_keys_init(struct subprocess_info *info, struct cred *cred) +{ + struct key *keyring = info->data; + + return install_session_keyring_to_cred(cred, keyring); +} + +/* + * Clean up a usermode helper with session keyring. + */ +static void umh_keys_cleanup(struct subprocess_info *info) +{ + struct key *keyring = info->data; + key_put(keyring); +} + +/* + * Call a usermode helper with a specific session keyring. + */ +static int call_usermodehelper_keys(const char *path, char **argv, char **envp, + struct key *session_keyring, int wait) +{ + struct subprocess_info *info; + + info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL, + umh_keys_init, umh_keys_cleanup, + session_keyring); + if (!info) + return -ENOMEM; + + key_get(session_keyring); + return call_usermodehelper_exec(info, wait); +} + +/* + * Request userspace finish the construction of a key + * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>" + */ +static int call_sbin_request_key(struct key *authkey, void *aux) +{ + static char const request_key[] = "/sbin/request-key"; + struct request_key_auth *rka = get_request_key_auth(authkey); + const struct cred *cred = current_cred(); + key_serial_t prkey, sskey; + struct key *key = rka->target_key, *keyring, *session; + char *argv[9], *envp[3], uid_str[12], gid_str[12]; + char key_str[12], keyring_str[3][12]; + char desc[20]; + int ret, i; + + kenter("{%d},{%d},%s", key->serial, authkey->serial, rka->op); + + ret = install_user_keyrings(); + if (ret < 0) + goto error_alloc; + + /* allocate a new session keyring */ + sprintf(desc, "_req.%u", key->serial); + + cred = get_current_cred(); + keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred, + KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, + KEY_ALLOC_QUOTA_OVERRUN, NULL, NULL); + put_cred(cred); + if (IS_ERR(keyring)) { + ret = PTR_ERR(keyring); + goto error_alloc; + } + + /* attach the auth key to the session keyring */ + ret = key_link(keyring, authkey); + if (ret < 0) + goto error_link; + + /* record the UID and GID */ + sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid)); + sprintf(gid_str, "%d", from_kgid(&init_user_ns, cred->fsgid)); + + /* we say which key is under construction */ + sprintf(key_str, "%d", key->serial); + + /* we specify the process's default keyrings */ + sprintf(keyring_str[0], "%d", + cred->thread_keyring ? cred->thread_keyring->serial : 0); + + prkey = 0; + if (cred->process_keyring) + prkey = cred->process_keyring->serial; + sprintf(keyring_str[1], "%d", prkey); + + rcu_read_lock(); + session = rcu_dereference(cred->session_keyring); + if (!session) + session = cred->user->session_keyring; + sskey = session->serial; + rcu_read_unlock(); + + sprintf(keyring_str[2], "%d", sskey); + + /* set up a minimal environment */ + i = 0; + envp[i++] = "HOME=/"; + envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; + envp[i] = NULL; + + /* set up the argument list */ + i = 0; + argv[i++] = (char *)request_key; + argv[i++] = (char *)rka->op; + argv[i++] = key_str; + argv[i++] = uid_str; + argv[i++] = gid_str; + argv[i++] = keyring_str[0]; + argv[i++] = keyring_str[1]; + argv[i++] = keyring_str[2]; + argv[i] = NULL; + + /* do it */ + ret = call_usermodehelper_keys(request_key, argv, envp, keyring, + UMH_WAIT_PROC); + kdebug("usermode -> 0x%x", ret); + if (ret >= 0) { + /* ret is the exit/wait code */ + if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) || + key_validate(key) < 0) + ret = -ENOKEY; + else + /* ignore any errors from userspace if the key was + * instantiated */ + ret = 0; + } + +error_link: + key_put(keyring); + +error_alloc: + complete_request_key(authkey, ret); + kleave(" = %d", ret); + return ret; +} + +/* + * Call out to userspace for key construction. + * + * Program failure is ignored in favour of key status. + */ +static int construct_key(struct key *key, const void *callout_info, + size_t callout_len, void *aux, + struct key *dest_keyring) +{ + request_key_actor_t actor; + struct key *authkey; + int ret; + + kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux); + + /* allocate an authorisation key */ + authkey = request_key_auth_new(key, "create", callout_info, callout_len, + dest_keyring); + if (IS_ERR(authkey)) + return PTR_ERR(authkey); + + /* Make the call */ + actor = call_sbin_request_key; + if (key->type->request_key) + actor = key->type->request_key; + + ret = actor(authkey, aux); + + /* check that the actor called complete_request_key() prior to + * returning an error */ + WARN_ON(ret < 0 && + !test_bit(KEY_FLAG_REVOKED, &authkey->flags)); + + key_put(authkey); + kleave(" = %d", ret); + return ret; +} + +/* + * Get the appropriate destination keyring for the request. + * + * The keyring selected is returned with an extra reference upon it which the + * caller must release. + */ +static int construct_get_dest_keyring(struct key **_dest_keyring) +{ + struct request_key_auth *rka; + const struct cred *cred = current_cred(); + struct key *dest_keyring = *_dest_keyring, *authkey; + int ret; + + kenter("%p", dest_keyring); + + /* find the appropriate keyring */ + if (dest_keyring) { + /* the caller supplied one */ + key_get(dest_keyring); + } else { + bool do_perm_check = true; + + /* use a default keyring; falling through the cases until we + * find one that we actually have */ + switch (cred->jit_keyring) { + case KEY_REQKEY_DEFL_DEFAULT: + case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: + if (cred->request_key_auth) { + authkey = cred->request_key_auth; + down_read(&authkey->sem); + rka = get_request_key_auth(authkey); + if (!test_bit(KEY_FLAG_REVOKED, + &authkey->flags)) + dest_keyring = + key_get(rka->dest_keyring); + up_read(&authkey->sem); + if (dest_keyring) { + do_perm_check = false; + break; + } + } + + case KEY_REQKEY_DEFL_THREAD_KEYRING: + dest_keyring = key_get(cred->thread_keyring); + if (dest_keyring) + break; + + case KEY_REQKEY_DEFL_PROCESS_KEYRING: + dest_keyring = key_get(cred->process_keyring); + if (dest_keyring) + break; + + case KEY_REQKEY_DEFL_SESSION_KEYRING: + rcu_read_lock(); + dest_keyring = key_get( + rcu_dereference(cred->session_keyring)); + rcu_read_unlock(); + + if (dest_keyring) + break; + + case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: + dest_keyring = + key_get(cred->user->session_keyring); + break; + + case KEY_REQKEY_DEFL_USER_KEYRING: + dest_keyring = key_get(cred->user->uid_keyring); + break; + + case KEY_REQKEY_DEFL_GROUP_KEYRING: + default: + BUG(); + } + + /* + * Require Write permission on the keyring. This is essential + * because the default keyring may be the session keyring, and + * joining a keyring only requires Search permission. + * + * However, this check is skipped for the "requestor keyring" so + * that /sbin/request-key can itself use request_key() to add + * keys to the original requestor's destination keyring. + */ + if (dest_keyring && do_perm_check) { + ret = key_permission(make_key_ref(dest_keyring, 1), + KEY_NEED_WRITE); + if (ret) { + key_put(dest_keyring); + return ret; + } + } + } + + *_dest_keyring = dest_keyring; + kleave(" [dk %d]", key_serial(dest_keyring)); + return 0; +} + +/* + * Allocate a new key in under-construction state and attempt to link it in to + * the requested keyring. + * + * May return a key that's already under construction instead if there was a + * race between two thread calling request_key(). + */ +static int construct_alloc_key(struct keyring_search_context *ctx, + struct key *dest_keyring, + unsigned long flags, + struct key_user *user, + struct key **_key) +{ + struct assoc_array_edit *edit; + struct key *key; + key_perm_t perm; + key_ref_t key_ref; + int ret; + + kenter("%s,%s,,,", + ctx->index_key.type->name, ctx->index_key.description); + + *_key = NULL; + mutex_lock(&user->cons_lock); + + perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; + perm |= KEY_USR_VIEW; + if (ctx->index_key.type->read) + perm |= KEY_POS_READ; + if (ctx->index_key.type == &key_type_keyring || + ctx->index_key.type->update) + perm |= KEY_POS_WRITE; + + key = key_alloc(ctx->index_key.type, ctx->index_key.description, + ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred, + perm, flags, NULL); + if (IS_ERR(key)) + goto alloc_failed; + + set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); + + if (dest_keyring) { + ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit); + if (ret < 0) + goto link_prealloc_failed; + } + + /* attach the key to the destination keyring under lock, but we do need + * to do another check just in case someone beat us to it whilst we + * waited for locks */ + mutex_lock(&key_construction_mutex); + + key_ref = search_process_keyrings(ctx); + if (!IS_ERR(key_ref)) + goto key_already_present; + + if (dest_keyring) + __key_link(key, &edit); + + mutex_unlock(&key_construction_mutex); + if (dest_keyring) + __key_link_end(dest_keyring, &ctx->index_key, edit); + mutex_unlock(&user->cons_lock); + *_key = key; + kleave(" = 0 [%d]", key_serial(key)); + return 0; + + /* the key is now present - we tell the caller that we found it by + * returning -EINPROGRESS */ +key_already_present: + key_put(key); + mutex_unlock(&key_construction_mutex); + key = key_ref_to_ptr(key_ref); + if (dest_keyring) { + ret = __key_link_check_live_key(dest_keyring, key); + if (ret == 0) + __key_link(key, &edit); + __key_link_end(dest_keyring, &ctx->index_key, edit); + if (ret < 0) + goto link_check_failed; + } + mutex_unlock(&user->cons_lock); + *_key = key; + kleave(" = -EINPROGRESS [%d]", key_serial(key)); + return -EINPROGRESS; + +link_check_failed: + mutex_unlock(&user->cons_lock); + key_put(key); + kleave(" = %d [linkcheck]", ret); + return ret; + +link_prealloc_failed: + mutex_unlock(&user->cons_lock); + key_put(key); + kleave(" = %d [prelink]", ret); + return ret; + +alloc_failed: + mutex_unlock(&user->cons_lock); + kleave(" = %ld", PTR_ERR(key)); + return PTR_ERR(key); +} + +/* + * Commence key construction. + */ +static struct key *construct_key_and_link(struct keyring_search_context *ctx, + const char *callout_info, + size_t callout_len, + void *aux, + struct key *dest_keyring, + unsigned long flags) +{ + struct key_user *user; + struct key *key; + int ret; + + kenter(""); + + if (ctx->index_key.type == &key_type_keyring) + return ERR_PTR(-EPERM); + + ret = construct_get_dest_keyring(&dest_keyring); + if (ret) + goto error; + + user = key_user_lookup(current_fsuid()); + if (!user) { + ret = -ENOMEM; + goto error_put_dest_keyring; + } + + ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key); + key_user_put(user); + + if (ret == 0) { + ret = construct_key(key, callout_info, callout_len, aux, + dest_keyring); + if (ret < 0) { + kdebug("cons failed"); + goto construction_failed; + } + } else if (ret == -EINPROGRESS) { + ret = 0; + } else { + goto error_put_dest_keyring; + } + + key_put(dest_keyring); + kleave(" = key %d", key_serial(key)); + return key; + +construction_failed: + key_negate_and_link(key, key_negative_timeout, NULL, NULL); + key_put(key); +error_put_dest_keyring: + key_put(dest_keyring); +error: + kleave(" = %d", ret); + return ERR_PTR(ret); +} + +/** + * request_key_and_link - Request a key and cache it in a keyring. + * @type: The type of key we want. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * @aux: Auxiliary data for the upcall. + * @dest_keyring: Where to cache the key. + * @flags: Flags to key_alloc(). + * + * A key matching the specified criteria is searched for in the process's + * keyrings and returned with its usage count incremented if found. Otherwise, + * if callout_info is not NULL, a key will be allocated and some service + * (probably in userspace) will be asked to instantiate it. + * + * If successfully found or created, the key will be linked to the destination + * keyring if one is provided. + * + * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED + * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was + * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT + * if insufficient key quota was available to create a new key; or -ENOMEM if + * insufficient memory was available. + * + * If the returned key was created, then it may still be under construction, + * and wait_for_key_construction() should be used to wait for that to complete. + */ +struct key *request_key_and_link(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len, + void *aux, + struct key *dest_keyring, + unsigned long flags) +{ + struct keyring_search_context ctx = { + .index_key.type = type, + .index_key.description = description, + .index_key.desc_len = strlen(description), + .cred = current_cred(), + .match_data.cmp = key_default_cmp, + .match_data.raw_data = description, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = (KEYRING_SEARCH_DO_STATE_CHECK | + KEYRING_SEARCH_SKIP_EXPIRED), + }; + struct key *key; + key_ref_t key_ref; + int ret; + + kenter("%s,%s,%p,%zu,%p,%p,%lx", + ctx.index_key.type->name, ctx.index_key.description, + callout_info, callout_len, aux, dest_keyring, flags); + + if (type->match_preparse) { + ret = type->match_preparse(&ctx.match_data); + if (ret < 0) { + key = ERR_PTR(ret); + goto error; + } + } + + /* search all the process keyrings for a key */ + key_ref = search_process_keyrings(&ctx); + + if (!IS_ERR(key_ref)) { + key = key_ref_to_ptr(key_ref); + if (dest_keyring) { + ret = key_link(dest_keyring, key); + if (ret < 0) { + key_put(key); + key = ERR_PTR(ret); + goto error_free; + } + } + } else if (PTR_ERR(key_ref) != -EAGAIN) { + key = ERR_CAST(key_ref); + } else { + /* the search failed, but the keyrings were searchable, so we + * should consult userspace if we can */ + key = ERR_PTR(-ENOKEY); + if (!callout_info) + goto error_free; + + key = construct_key_and_link(&ctx, callout_info, callout_len, + aux, dest_keyring, flags); + } + +error_free: + if (type->match_free) + type->match_free(&ctx.match_data); +error: + kleave(" = %p", key); + return key; +} + +/** + * wait_for_key_construction - Wait for construction of a key to complete + * @key: The key being waited for. + * @intr: Whether to wait interruptibly. + * + * Wait for a key to finish being constructed. + * + * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY + * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was + * revoked or expired. + */ +int wait_for_key_construction(struct key *key, bool intr) +{ + int ret; + + ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT, + intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); + if (ret) + return -ERESTARTSYS; + ret = key_read_state(key); + if (ret < 0) + return ret; + return key_validate(key); +} +EXPORT_SYMBOL(wait_for_key_construction); + +/** + * request_key - Request a key and wait for construction + * @type: Type of key. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found, new keys are always allocated in the user's quota, + * the callout_info must be a NUL-terminated string and no auxiliary data can + * be passed. + * + * Furthermore, it then works as wait_for_key_construction() to wait for the + * completion of keys undergoing construction with a non-interruptible wait. + */ +struct key *request_key(struct key_type *type, + const char *description, + const char *callout_info) +{ + struct key *key; + size_t callout_len = 0; + int ret; + + if (callout_info) + callout_len = strlen(callout_info); + key = request_key_and_link(type, description, callout_info, callout_len, + NULL, NULL, KEY_ALLOC_IN_QUOTA); + if (!IS_ERR(key)) { + ret = wait_for_key_construction(key, false); + if (ret < 0) { + key_put(key); + return ERR_PTR(ret); + } + } + return key; +} +EXPORT_SYMBOL(request_key); + +/** + * request_key_with_auxdata - Request a key with auxiliary data for the upcaller + * @type: The type of key we want. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * @aux: Auxiliary data for the upcall. + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found and new keys are always allocated in the user's quota. + * + * Furthermore, it then works as wait_for_key_construction() to wait for the + * completion of keys undergoing construction with a non-interruptible wait. + */ +struct key *request_key_with_auxdata(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len, + void *aux) +{ + struct key *key; + int ret; + + key = request_key_and_link(type, description, callout_info, callout_len, + aux, NULL, KEY_ALLOC_IN_QUOTA); + if (!IS_ERR(key)) { + ret = wait_for_key_construction(key, false); + if (ret < 0) { + key_put(key); + return ERR_PTR(ret); + } + } + return key; +} +EXPORT_SYMBOL(request_key_with_auxdata); + +/* + * request_key_async - Request a key (allow async construction) + * @type: Type of key. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found, new keys are always allocated in the user's quota and + * no auxiliary data can be passed. + * + * The caller should call wait_for_key_construction() to wait for the + * completion of the returned key if it is still undergoing construction. + */ +struct key *request_key_async(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len) +{ + return request_key_and_link(type, description, callout_info, + callout_len, NULL, NULL, + KEY_ALLOC_IN_QUOTA); +} +EXPORT_SYMBOL(request_key_async); + +/* + * request a key with auxiliary data for the upcaller (allow async construction) + * @type: Type of key. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * @aux: Auxiliary data for the upcall. + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found and new keys are always allocated in the user's quota. + * + * The caller should call wait_for_key_construction() to wait for the + * completion of the returned key if it is still undergoing construction. + */ +struct key *request_key_async_with_auxdata(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len, + void *aux) +{ + return request_key_and_link(type, description, callout_info, + callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA); +} +EXPORT_SYMBOL(request_key_async_with_auxdata); diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c new file mode 100644 index 000000000..13ac3b1e5 --- /dev/null +++ b/security/keys/request_key_auth.c @@ -0,0 +1,275 @@ +/* Request key authorisation token key definition. + * + * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * See Documentation/security/keys/request-key.rst + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/err.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include "internal.h" +#include <keys/request_key_auth-type.h> + +static int request_key_auth_preparse(struct key_preparsed_payload *); +static void request_key_auth_free_preparse(struct key_preparsed_payload *); +static int request_key_auth_instantiate(struct key *, + struct key_preparsed_payload *); +static void request_key_auth_describe(const struct key *, struct seq_file *); +static void request_key_auth_revoke(struct key *); +static void request_key_auth_destroy(struct key *); +static long request_key_auth_read(const struct key *, char *, size_t); + +/* + * The request-key authorisation key type definition. + */ +struct key_type key_type_request_key_auth = { + .name = ".request_key_auth", + .def_datalen = sizeof(struct request_key_auth), + .preparse = request_key_auth_preparse, + .free_preparse = request_key_auth_free_preparse, + .instantiate = request_key_auth_instantiate, + .describe = request_key_auth_describe, + .revoke = request_key_auth_revoke, + .destroy = request_key_auth_destroy, + .read = request_key_auth_read, +}; + +static int request_key_auth_preparse(struct key_preparsed_payload *prep) +{ + return 0; +} + +static void request_key_auth_free_preparse(struct key_preparsed_payload *prep) +{ +} + +/* + * Instantiate a request-key authorisation key. + */ +static int request_key_auth_instantiate(struct key *key, + struct key_preparsed_payload *prep) +{ + key->payload.data[0] = (struct request_key_auth *)prep->data; + return 0; +} + +/* + * Describe an authorisation token. + */ +static void request_key_auth_describe(const struct key *key, + struct seq_file *m) +{ + struct request_key_auth *rka = get_request_key_auth(key); + + if (!rka) + return; + + seq_puts(m, "key:"); + seq_puts(m, key->description); + if (key_is_positive(key)) + seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); +} + +/* + * Read the callout_info data (retrieves the callout information). + * - the key's semaphore is read-locked + */ +static long request_key_auth_read(const struct key *key, + char *buffer, size_t buflen) +{ + struct request_key_auth *rka = get_request_key_auth(key); + size_t datalen; + long ret; + + if (!rka) + return -EKEYREVOKED; + + datalen = rka->callout_len; + ret = datalen; + + /* we can return the data as is */ + if (buffer && buflen > 0) { + if (buflen > datalen) + buflen = datalen; + + memcpy(buffer, rka->callout_info, buflen); + } + + return ret; +} + +/* + * Handle revocation of an authorisation token key. + * + * Called with the key sem write-locked. + */ +static void request_key_auth_revoke(struct key *key) +{ + struct request_key_auth *rka = get_request_key_auth(key); + + kenter("{%d}", key->serial); + + if (rka->cred) { + put_cred(rka->cred); + rka->cred = NULL; + } +} + +static void free_request_key_auth(struct request_key_auth *rka) +{ + if (!rka) + return; + key_put(rka->target_key); + key_put(rka->dest_keyring); + if (rka->cred) + put_cred(rka->cred); + kfree(rka->callout_info); + kfree(rka); +} + +/* + * Destroy an instantiation authorisation token key. + */ +static void request_key_auth_destroy(struct key *key) +{ + struct request_key_auth *rka = get_request_key_auth(key); + + kenter("{%d}", key->serial); + + free_request_key_auth(rka); +} + +/* + * Create an authorisation token for /sbin/request-key or whoever to gain + * access to the caller's security data. + */ +struct key *request_key_auth_new(struct key *target, const char *op, + const void *callout_info, size_t callout_len, + struct key *dest_keyring) +{ + struct request_key_auth *rka, *irka; + const struct cred *cred = current->cred; + struct key *authkey = NULL; + char desc[20]; + int ret = -ENOMEM; + + kenter("%d,", target->serial); + + /* allocate a auth record */ + rka = kzalloc(sizeof(*rka), GFP_KERNEL); + if (!rka) + goto error; + rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL); + if (!rka->callout_info) + goto error_free_rka; + rka->callout_len = callout_len; + strlcpy(rka->op, op, sizeof(rka->op)); + + /* see if the calling process is already servicing the key request of + * another process */ + if (cred->request_key_auth) { + /* it is - use that instantiation context here too */ + down_read(&cred->request_key_auth->sem); + + /* if the auth key has been revoked, then the key we're + * servicing is already instantiated */ + if (test_bit(KEY_FLAG_REVOKED, + &cred->request_key_auth->flags)) { + up_read(&cred->request_key_auth->sem); + ret = -EKEYREVOKED; + goto error_free_rka; + } + + irka = cred->request_key_auth->payload.data[0]; + rka->cred = get_cred(irka->cred); + rka->pid = irka->pid; + + up_read(&cred->request_key_auth->sem); + } + else { + /* it isn't - use this process as the context */ + rka->cred = get_cred(cred); + rka->pid = current->pid; + } + + rka->target_key = key_get(target); + rka->dest_keyring = key_get(dest_keyring); + + /* allocate the auth key */ + sprintf(desc, "%x", target->serial); + + authkey = key_alloc(&key_type_request_key_auth, desc, + cred->fsuid, cred->fsgid, cred, + KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | + KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL); + if (IS_ERR(authkey)) { + ret = PTR_ERR(authkey); + goto error_free_rka; + } + + /* construct the auth key */ + ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); + if (ret < 0) + goto error_put_authkey; + + kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage)); + return authkey; + +error_put_authkey: + key_put(authkey); +error_free_rka: + free_request_key_auth(rka); +error: + kleave("= %d", ret); + return ERR_PTR(ret); +} + +/* + * Search the current process's keyrings for the authorisation key for + * instantiation of a key. + */ +struct key *key_get_instantiation_authkey(key_serial_t target_id) +{ + char description[16]; + struct keyring_search_context ctx = { + .index_key.type = &key_type_request_key_auth, + .index_key.description = description, + .cred = current_cred(), + .match_data.cmp = key_default_cmp, + .match_data.raw_data = description, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = KEYRING_SEARCH_DO_STATE_CHECK, + }; + struct key *authkey; + key_ref_t authkey_ref; + + ctx.index_key.desc_len = sprintf(description, "%x", target_id); + + authkey_ref = search_process_keyrings(&ctx); + + if (IS_ERR(authkey_ref)) { + authkey = ERR_CAST(authkey_ref); + if (authkey == ERR_PTR(-EAGAIN)) + authkey = ERR_PTR(-ENOKEY); + goto error; + } + + authkey = key_ref_to_ptr(authkey_ref); + if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { + key_put(authkey); + authkey = ERR_PTR(-EKEYREVOKED); + } + +error: + return authkey; +} diff --git a/security/keys/sysctl.c b/security/keys/sysctl.c new file mode 100644 index 000000000..b68faa1a5 --- /dev/null +++ b/security/keys/sysctl.c @@ -0,0 +1,76 @@ +/* Key management controls + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/key.h> +#include <linux/sysctl.h> +#include "internal.h" + +static const int zero, one = 1, max = INT_MAX; + +struct ctl_table key_sysctls[] = { + { + .procname = "maxkeys", + .data = &key_quota_maxkeys, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, + }, + { + .procname = "maxbytes", + .data = &key_quota_maxbytes, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, + }, + { + .procname = "root_maxkeys", + .data = &key_quota_root_maxkeys, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, + }, + { + .procname = "root_maxbytes", + .data = &key_quota_root_maxbytes, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &one, + .extra2 = (void *) &max, + }, + { + .procname = "gc_delay", + .data = &key_gc_delay, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &zero, + .extra2 = (void *) &max, + }, +#ifdef CONFIG_PERSISTENT_KEYRINGS + { + .procname = "persistent_keyring_expiry", + .data = &persistent_keyring_expiry, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &zero, + .extra2 = (void *) &max, + }, +#endif + { } +}; diff --git a/security/keys/trusted.c b/security/keys/trusted.c new file mode 100644 index 000000000..9179a5bbf --- /dev/null +++ b/security/keys/trusted.c @@ -0,0 +1,1232 @@ +/* + * Copyright (C) 2010 IBM Corporation + * + * Author: + * David Safford <safford@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * See Documentation/security/keys/trusted-encrypted.rst + */ + +#include <crypto/hash_info.h> +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/parser.h> +#include <linux/string.h> +#include <linux/err.h> +#include <keys/user-type.h> +#include <keys/trusted-type.h> +#include <linux/key-type.h> +#include <linux/rcupdate.h> +#include <linux/crypto.h> +#include <crypto/hash.h> +#include <crypto/sha.h> +#include <linux/capability.h> +#include <linux/tpm.h> +#include <linux/tpm_command.h> + +#include "trusted.h" + +static const char hmac_alg[] = "hmac(sha1)"; +static const char hash_alg[] = "sha1"; + +struct sdesc { + struct shash_desc shash; + char ctx[]; +}; + +static struct crypto_shash *hashalg; +static struct crypto_shash *hmacalg; + +static struct sdesc *init_sdesc(struct crypto_shash *alg) +{ + struct sdesc *sdesc; + int size; + + size = sizeof(struct shash_desc) + crypto_shash_descsize(alg); + sdesc = kmalloc(size, GFP_KERNEL); + if (!sdesc) + return ERR_PTR(-ENOMEM); + sdesc->shash.tfm = alg; + sdesc->shash.flags = 0x0; + return sdesc; +} + +static int TSS_sha1(const unsigned char *data, unsigned int datalen, + unsigned char *digest) +{ + struct sdesc *sdesc; + int ret; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest); + kzfree(sdesc); + return ret; +} + +static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, + unsigned int keylen, ...) +{ + struct sdesc *sdesc; + va_list argp; + unsigned int dlen; + unsigned char *data; + int ret; + + sdesc = init_sdesc(hmacalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hmac_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_setkey(hmacalg, key, keylen); + if (ret < 0) + goto out; + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + + va_start(argp, keylen); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + data = va_arg(argp, unsigned char *); + if (data == NULL) { + ret = -EINVAL; + break; + } + ret = crypto_shash_update(&sdesc->shash, data, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, digest); +out: + kzfree(sdesc); + return ret; +} + +/* + * calculate authorization info fields to send to TPM + */ +static int TSS_authhmac(unsigned char *digest, const unsigned char *key, + unsigned int keylen, unsigned char *h1, + unsigned char *h2, unsigned char h3, ...) +{ + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned char *data; + unsigned char c; + int ret; + va_list argp; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + c = h3; + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + va_start(argp, h3); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + data = va_arg(argp, unsigned char *); + if (!data) { + ret = -EINVAL; + break; + } + ret = crypto_shash_update(&sdesc->shash, data, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (!ret) + ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, h1, + TPM_NONCE_SIZE, h2, 1, &c, 0, 0); +out: + kzfree(sdesc); + return ret; +} + +/* + * verify the AUTH1_COMMAND (Seal) result from TPM + */ +static int TSS_checkhmac1(unsigned char *buffer, + const uint32_t command, + const unsigned char *ononce, + const unsigned char *key, + unsigned int keylen, ...) +{ + uint32_t bufsize; + uint16_t tag; + uint32_t ordinal; + uint32_t result; + unsigned char *enonce; + unsigned char *continueflag; + unsigned char *authdata; + unsigned char testhmac[SHA1_DIGEST_SIZE]; + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned int dpos; + va_list argp; + int ret; + + bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); + tag = LOAD16(buffer, 0); + ordinal = command; + result = LOAD32N(buffer, TPM_RETURN_OFFSET); + if (tag == TPM_TAG_RSP_COMMAND) + return 0; + if (tag != TPM_TAG_RSP_AUTH1_COMMAND) + return -EINVAL; + authdata = buffer + bufsize - SHA1_DIGEST_SIZE; + continueflag = authdata - 1; + enonce = continueflag - TPM_NONCE_SIZE; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, + sizeof result); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, + sizeof ordinal); + if (ret < 0) + goto out; + va_start(argp, keylen); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + dpos = va_arg(argp, unsigned int); + ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (ret < 0) + goto out; + + ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest, + TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce, + 1, continueflag, 0, 0); + if (ret < 0) + goto out; + + if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) + ret = -EINVAL; +out: + kzfree(sdesc); + return ret; +} + +/* + * verify the AUTH2_COMMAND (unseal) result from TPM + */ +static int TSS_checkhmac2(unsigned char *buffer, + const uint32_t command, + const unsigned char *ononce, + const unsigned char *key1, + unsigned int keylen1, + const unsigned char *key2, + unsigned int keylen2, ...) +{ + uint32_t bufsize; + uint16_t tag; + uint32_t ordinal; + uint32_t result; + unsigned char *enonce1; + unsigned char *continueflag1; + unsigned char *authdata1; + unsigned char *enonce2; + unsigned char *continueflag2; + unsigned char *authdata2; + unsigned char testhmac1[SHA1_DIGEST_SIZE]; + unsigned char testhmac2[SHA1_DIGEST_SIZE]; + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned int dpos; + va_list argp; + int ret; + + bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); + tag = LOAD16(buffer, 0); + ordinal = command; + result = LOAD32N(buffer, TPM_RETURN_OFFSET); + + if (tag == TPM_TAG_RSP_COMMAND) + return 0; + if (tag != TPM_TAG_RSP_AUTH2_COMMAND) + return -EINVAL; + authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1 + + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE); + authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE); + continueflag1 = authdata1 - 1; + continueflag2 = authdata2 - 1; + enonce1 = continueflag1 - TPM_NONCE_SIZE; + enonce2 = continueflag2 - TPM_NONCE_SIZE; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, + sizeof result); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, + sizeof ordinal); + if (ret < 0) + goto out; + + va_start(argp, keylen2); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + dpos = va_arg(argp, unsigned int); + ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (ret < 0) + goto out; + + ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, enonce1, + TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); + if (ret < 0) + goto out; + if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { + ret = -EINVAL; + goto out; + } + ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, enonce2, + TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); + if (ret < 0) + goto out; + if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) + ret = -EINVAL; +out: + kzfree(sdesc); + return ret; +} + +/* + * For key specific tpm requests, we will generate and send our + * own TPM command packets using the drivers send function. + */ +static int trusted_tpm_send(unsigned char *cmd, size_t buflen) +{ + int rc; + + dump_tpm_buf(cmd); + rc = tpm_send(NULL, cmd, buflen); + dump_tpm_buf(cmd); + if (rc > 0) + /* Can't return positive return codes values to keyctl */ + rc = -EPERM; + return rc; +} + +/* + * Lock a trusted key, by extending a selected PCR. + * + * Prevents a trusted key that is sealed to PCRs from being accessed. + * This uses the tpm driver's extend function. + */ +static int pcrlock(const int pcrnum) +{ + unsigned char hash[SHA1_DIGEST_SIZE]; + int ret; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + ret = tpm_get_random(NULL, hash, SHA1_DIGEST_SIZE); + if (ret != SHA1_DIGEST_SIZE) + return ret; + return tpm_pcr_extend(NULL, pcrnum, hash) ? -EINVAL : 0; +} + +/* + * Create an object specific authorisation protocol (OSAP) session + */ +static int osap(struct tpm_buf *tb, struct osapsess *s, + const unsigned char *key, uint16_t type, uint32_t handle) +{ + unsigned char enonce[TPM_NONCE_SIZE]; + unsigned char ononce[TPM_NONCE_SIZE]; + int ret; + + ret = tpm_get_random(NULL, ononce, TPM_NONCE_SIZE); + if (ret != TPM_NONCE_SIZE) + return ret; + + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_COMMAND); + store32(tb, TPM_OSAP_SIZE); + store32(tb, TPM_ORD_OSAP); + store16(tb, type); + store32(tb, handle); + storebytes(tb, ononce, TPM_NONCE_SIZE); + + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) + return ret; + + s->handle = LOAD32(tb->data, TPM_DATA_OFFSET); + memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]), + TPM_NONCE_SIZE); + memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) + + TPM_NONCE_SIZE]), TPM_NONCE_SIZE); + return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE, + enonce, TPM_NONCE_SIZE, ononce, 0, 0); +} + +/* + * Create an object independent authorisation protocol (oiap) session + */ +static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce) +{ + int ret; + + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_COMMAND); + store32(tb, TPM_OIAP_SIZE); + store32(tb, TPM_ORD_OIAP); + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) + return ret; + + *handle = LOAD32(tb->data, TPM_DATA_OFFSET); + memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)], + TPM_NONCE_SIZE); + return 0; +} + +struct tpm_digests { + unsigned char encauth[SHA1_DIGEST_SIZE]; + unsigned char pubauth[SHA1_DIGEST_SIZE]; + unsigned char xorwork[SHA1_DIGEST_SIZE * 2]; + unsigned char xorhash[SHA1_DIGEST_SIZE]; + unsigned char nonceodd[TPM_NONCE_SIZE]; +}; + +/* + * Have the TPM seal(encrypt) the trusted key, possibly based on + * Platform Configuration Registers (PCRs). AUTH1 for sealing key. + */ +static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, + uint32_t keyhandle, const unsigned char *keyauth, + const unsigned char *data, uint32_t datalen, + unsigned char *blob, uint32_t *bloblen, + const unsigned char *blobauth, + const unsigned char *pcrinfo, uint32_t pcrinfosize) +{ + struct osapsess sess; + struct tpm_digests *td; + unsigned char cont; + uint32_t ordinal; + uint32_t pcrsize; + uint32_t datsize; + int sealinfosize; + int encdatasize; + int storedsize; + int ret; + int i; + + /* alloc some work space for all the hashes */ + td = kmalloc(sizeof *td, GFP_KERNEL); + if (!td) + return -ENOMEM; + + /* get session for sealing key */ + ret = osap(tb, &sess, keyauth, keytype, keyhandle); + if (ret < 0) + goto out; + dump_sess(&sess); + + /* calculate encrypted authorization value */ + memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE); + memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE); + ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash); + if (ret < 0) + goto out; + + ret = tpm_get_random(NULL, td->nonceodd, TPM_NONCE_SIZE); + if (ret != TPM_NONCE_SIZE) + goto out; + ordinal = htonl(TPM_ORD_SEAL); + datsize = htonl(datalen); + pcrsize = htonl(pcrinfosize); + cont = 0; + + /* encrypt data authorization key */ + for (i = 0; i < SHA1_DIGEST_SIZE; ++i) + td->encauth[i] = td->xorhash[i] ^ blobauth[i]; + + /* calculate authorization HMAC value */ + if (pcrinfosize == 0) { + /* no pcr info specified */ + ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, + sess.enonce, td->nonceodd, cont, + sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, + td->encauth, sizeof(uint32_t), &pcrsize, + sizeof(uint32_t), &datsize, datalen, data, 0, + 0); + } else { + /* pcr info specified */ + ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, + sess.enonce, td->nonceodd, cont, + sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, + td->encauth, sizeof(uint32_t), &pcrsize, + pcrinfosize, pcrinfo, sizeof(uint32_t), + &datsize, datalen, data, 0, 0); + } + if (ret < 0) + goto out; + + /* build and send the TPM request packet */ + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_AUTH1_COMMAND); + store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen); + store32(tb, TPM_ORD_SEAL); + store32(tb, keyhandle); + storebytes(tb, td->encauth, SHA1_DIGEST_SIZE); + store32(tb, pcrinfosize); + storebytes(tb, pcrinfo, pcrinfosize); + store32(tb, datalen); + storebytes(tb, data, datalen); + store32(tb, sess.handle); + storebytes(tb, td->nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE); + + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) + goto out; + + /* calculate the size of the returned Blob */ + sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t)); + encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) + + sizeof(uint32_t) + sealinfosize); + storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize + + sizeof(uint32_t) + encdatasize; + + /* check the HMAC in the response */ + ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret, + SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0, + 0); + + /* copy the returned blob to caller */ + if (!ret) { + memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize); + *bloblen = storedsize; + } +out: + kzfree(td); + return ret; +} + +/* + * use the AUTH2_COMMAND form of unseal, to authorize both key and blob + */ +static int tpm_unseal(struct tpm_buf *tb, + uint32_t keyhandle, const unsigned char *keyauth, + const unsigned char *blob, int bloblen, + const unsigned char *blobauth, + unsigned char *data, unsigned int *datalen) +{ + unsigned char nonceodd[TPM_NONCE_SIZE]; + unsigned char enonce1[TPM_NONCE_SIZE]; + unsigned char enonce2[TPM_NONCE_SIZE]; + unsigned char authdata1[SHA1_DIGEST_SIZE]; + unsigned char authdata2[SHA1_DIGEST_SIZE]; + uint32_t authhandle1 = 0; + uint32_t authhandle2 = 0; + unsigned char cont = 0; + uint32_t ordinal; + uint32_t keyhndl; + int ret; + + /* sessions for unsealing key and data */ + ret = oiap(tb, &authhandle1, enonce1); + if (ret < 0) { + pr_info("trusted_key: oiap failed (%d)\n", ret); + return ret; + } + ret = oiap(tb, &authhandle2, enonce2); + if (ret < 0) { + pr_info("trusted_key: oiap failed (%d)\n", ret); + return ret; + } + + ordinal = htonl(TPM_ORD_UNSEAL); + keyhndl = htonl(SRKHANDLE); + ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE); + if (ret != TPM_NONCE_SIZE) { + pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); + return ret; + } + ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, + enonce1, nonceodd, cont, sizeof(uint32_t), + &ordinal, bloblen, blob, 0, 0); + if (ret < 0) + return ret; + ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE, + enonce2, nonceodd, cont, sizeof(uint32_t), + &ordinal, bloblen, blob, 0, 0); + if (ret < 0) + return ret; + + /* build and send TPM request packet */ + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_AUTH2_COMMAND); + store32(tb, TPM_UNSEAL_SIZE + bloblen); + store32(tb, TPM_ORD_UNSEAL); + store32(tb, keyhandle); + storebytes(tb, blob, bloblen); + store32(tb, authhandle1); + storebytes(tb, nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(tb, authdata1, SHA1_DIGEST_SIZE); + store32(tb, authhandle2); + storebytes(tb, nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(tb, authdata2, SHA1_DIGEST_SIZE); + + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) { + pr_info("trusted_key: authhmac failed (%d)\n", ret); + return ret; + } + + *datalen = LOAD32(tb->data, TPM_DATA_OFFSET); + ret = TSS_checkhmac2(tb->data, ordinal, nonceodd, + keyauth, SHA1_DIGEST_SIZE, + blobauth, SHA1_DIGEST_SIZE, + sizeof(uint32_t), TPM_DATA_OFFSET, + *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0, + 0); + if (ret < 0) { + pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret); + return ret; + } + memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen); + return 0; +} + +/* + * Have the TPM seal(encrypt) the symmetric key + */ +static int key_seal(struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + struct tpm_buf *tb; + int ret; + + tb = kzalloc(sizeof *tb, GFP_KERNEL); + if (!tb) + return -ENOMEM; + + /* include migratable flag at end of sealed key */ + p->key[p->key_len] = p->migratable; + + ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth, + p->key, p->key_len + 1, p->blob, &p->blob_len, + o->blobauth, o->pcrinfo, o->pcrinfo_len); + if (ret < 0) + pr_info("trusted_key: srkseal failed (%d)\n", ret); + + kzfree(tb); + return ret; +} + +/* + * Have the TPM unseal(decrypt) the symmetric key + */ +static int key_unseal(struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + struct tpm_buf *tb; + int ret; + + tb = kzalloc(sizeof *tb, GFP_KERNEL); + if (!tb) + return -ENOMEM; + + ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len, + o->blobauth, p->key, &p->key_len); + if (ret < 0) + pr_info("trusted_key: srkunseal failed (%d)\n", ret); + else + /* pull migratable flag out of sealed key */ + p->migratable = p->key[--p->key_len]; + + kzfree(tb); + return ret; +} + +enum { + Opt_err = -1, + Opt_new, Opt_load, Opt_update, + Opt_keyhandle, Opt_keyauth, Opt_blobauth, + Opt_pcrinfo, Opt_pcrlock, Opt_migratable, + Opt_hash, + Opt_policydigest, + Opt_policyhandle, +}; + +static const match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_load, "load"}, + {Opt_update, "update"}, + {Opt_keyhandle, "keyhandle=%s"}, + {Opt_keyauth, "keyauth=%s"}, + {Opt_blobauth, "blobauth=%s"}, + {Opt_pcrinfo, "pcrinfo=%s"}, + {Opt_pcrlock, "pcrlock=%s"}, + {Opt_migratable, "migratable=%s"}, + {Opt_hash, "hash=%s"}, + {Opt_policydigest, "policydigest=%s"}, + {Opt_policyhandle, "policyhandle=%s"}, + {Opt_err, NULL} +}; + +/* can have zero or more token= options */ +static int getoptions(char *c, struct trusted_key_payload *pay, + struct trusted_key_options *opt) +{ + substring_t args[MAX_OPT_ARGS]; + char *p = c; + int token; + int res; + unsigned long handle; + unsigned long lock; + unsigned long token_mask = 0; + unsigned int digest_len; + int i; + int tpm2; + + tpm2 = tpm_is_tpm2(NULL); + if (tpm2 < 0) + return tpm2; + + opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1; + + while ((p = strsep(&c, " \t"))) { + if (*p == '\0' || *p == ' ' || *p == '\t') + continue; + token = match_token(p, key_tokens, args); + if (test_and_set_bit(token, &token_mask)) + return -EINVAL; + + switch (token) { + case Opt_pcrinfo: + opt->pcrinfo_len = strlen(args[0].from) / 2; + if (opt->pcrinfo_len > MAX_PCRINFO_SIZE) + return -EINVAL; + res = hex2bin(opt->pcrinfo, args[0].from, + opt->pcrinfo_len); + if (res < 0) + return -EINVAL; + break; + case Opt_keyhandle: + res = kstrtoul(args[0].from, 16, &handle); + if (res < 0) + return -EINVAL; + opt->keytype = SEAL_keytype; + opt->keyhandle = handle; + break; + case Opt_keyauth: + if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) + return -EINVAL; + res = hex2bin(opt->keyauth, args[0].from, + SHA1_DIGEST_SIZE); + if (res < 0) + return -EINVAL; + break; + case Opt_blobauth: + if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) + return -EINVAL; + res = hex2bin(opt->blobauth, args[0].from, + SHA1_DIGEST_SIZE); + if (res < 0) + return -EINVAL; + break; + case Opt_migratable: + if (*args[0].from == '0') + pay->migratable = 0; + else if (*args[0].from != '1') + return -EINVAL; + break; + case Opt_pcrlock: + res = kstrtoul(args[0].from, 10, &lock); + if (res < 0) + return -EINVAL; + opt->pcrlock = lock; + break; + case Opt_hash: + if (test_bit(Opt_policydigest, &token_mask)) + return -EINVAL; + for (i = 0; i < HASH_ALGO__LAST; i++) { + if (!strcmp(args[0].from, hash_algo_name[i])) { + opt->hash = i; + break; + } + } + if (i == HASH_ALGO__LAST) + return -EINVAL; + if (!tpm2 && i != HASH_ALGO_SHA1) { + pr_info("trusted_key: TPM 1.x only supports SHA-1.\n"); + return -EINVAL; + } + break; + case Opt_policydigest: + digest_len = hash_digest_size[opt->hash]; + if (!tpm2 || strlen(args[0].from) != (2 * digest_len)) + return -EINVAL; + res = hex2bin(opt->policydigest, args[0].from, + digest_len); + if (res < 0) + return -EINVAL; + opt->policydigest_len = digest_len; + break; + case Opt_policyhandle: + if (!tpm2) + return -EINVAL; + res = kstrtoul(args[0].from, 16, &handle); + if (res < 0) + return -EINVAL; + opt->policyhandle = handle; + break; + default: + return -EINVAL; + } + } + return 0; +} + +/* + * datablob_parse - parse the keyctl data and fill in the + * payload and options structures + * + * On success returns 0, otherwise -EINVAL. + */ +static int datablob_parse(char *datablob, struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + substring_t args[MAX_OPT_ARGS]; + long keylen; + int ret = -EINVAL; + int key_cmd; + char *c; + + /* main command */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + key_cmd = match_token(c, key_tokens, args); + switch (key_cmd) { + case Opt_new: + /* first argument is key size */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + ret = kstrtol(c, 10, &keylen); + if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) + return -EINVAL; + p->key_len = keylen; + ret = getoptions(datablob, p, o); + if (ret < 0) + return ret; + ret = Opt_new; + break; + case Opt_load: + /* first argument is sealed blob */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + p->blob_len = strlen(c) / 2; + if (p->blob_len > MAX_BLOB_SIZE) + return -EINVAL; + ret = hex2bin(p->blob, c, p->blob_len); + if (ret < 0) + return -EINVAL; + ret = getoptions(datablob, p, o); + if (ret < 0) + return ret; + ret = Opt_load; + break; + case Opt_update: + /* all arguments are options */ + ret = getoptions(datablob, p, o); + if (ret < 0) + return ret; + ret = Opt_update; + break; + case Opt_err: + return -EINVAL; + break; + } + return ret; +} + +static struct trusted_key_options *trusted_options_alloc(void) +{ + struct trusted_key_options *options; + int tpm2; + + tpm2 = tpm_is_tpm2(NULL); + if (tpm2 < 0) + return NULL; + + options = kzalloc(sizeof *options, GFP_KERNEL); + if (options) { + /* set any non-zero defaults */ + options->keytype = SRK_keytype; + + if (!tpm2) + options->keyhandle = SRKHANDLE; + } + return options; +} + +static struct trusted_key_payload *trusted_payload_alloc(struct key *key) +{ + struct trusted_key_payload *p = NULL; + int ret; + + ret = key_payload_reserve(key, sizeof *p); + if (ret < 0) + return p; + p = kzalloc(sizeof *p, GFP_KERNEL); + if (p) + p->migratable = 1; /* migratable by default */ + return p; +} + +/* + * trusted_instantiate - create a new trusted key + * + * Unseal an existing trusted blob or, for a new key, get a + * random key, then seal and create a trusted key-type key, + * adding it to the specified keyring. + * + * On success, return 0. Otherwise return errno. + */ +static int trusted_instantiate(struct key *key, + struct key_preparsed_payload *prep) +{ + struct trusted_key_payload *payload = NULL; + struct trusted_key_options *options = NULL; + size_t datalen = prep->datalen; + char *datablob; + int ret = 0; + int key_cmd; + size_t key_len; + int tpm2; + + tpm2 = tpm_is_tpm2(NULL); + if (tpm2 < 0) + return tpm2; + + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + memcpy(datablob, prep->data, datalen); + datablob[datalen] = '\0'; + + options = trusted_options_alloc(); + if (!options) { + ret = -ENOMEM; + goto out; + } + payload = trusted_payload_alloc(key); + if (!payload) { + ret = -ENOMEM; + goto out; + } + + key_cmd = datablob_parse(datablob, payload, options); + if (key_cmd < 0) { + ret = key_cmd; + goto out; + } + + if (!options->keyhandle) { + ret = -EINVAL; + goto out; + } + + dump_payload(payload); + dump_options(options); + + switch (key_cmd) { + case Opt_load: + if (tpm2) + ret = tpm_unseal_trusted(NULL, payload, options); + else + ret = key_unseal(payload, options); + dump_payload(payload); + dump_options(options); + if (ret < 0) + pr_info("trusted_key: key_unseal failed (%d)\n", ret); + break; + case Opt_new: + key_len = payload->key_len; + ret = tpm_get_random(NULL, payload->key, key_len); + if (ret != key_len) { + pr_info("trusted_key: key_create failed (%d)\n", ret); + goto out; + } + if (tpm2) + ret = tpm_seal_trusted(NULL, payload, options); + else + ret = key_seal(payload, options); + if (ret < 0) + pr_info("trusted_key: key_seal failed (%d)\n", ret); + break; + default: + ret = -EINVAL; + goto out; + } + if (!ret && options->pcrlock) + ret = pcrlock(options->pcrlock); +out: + kzfree(datablob); + kzfree(options); + if (!ret) + rcu_assign_keypointer(key, payload); + else + kzfree(payload); + return ret; +} + +static void trusted_rcu_free(struct rcu_head *rcu) +{ + struct trusted_key_payload *p; + + p = container_of(rcu, struct trusted_key_payload, rcu); + kzfree(p); +} + +/* + * trusted_update - reseal an existing key with new PCR values + */ +static int trusted_update(struct key *key, struct key_preparsed_payload *prep) +{ + struct trusted_key_payload *p; + struct trusted_key_payload *new_p; + struct trusted_key_options *new_o; + size_t datalen = prep->datalen; + char *datablob; + int ret = 0; + + if (key_is_negative(key)) + return -ENOKEY; + p = key->payload.data[0]; + if (!p->migratable) + return -EPERM; + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + new_o = trusted_options_alloc(); + if (!new_o) { + ret = -ENOMEM; + goto out; + } + new_p = trusted_payload_alloc(key); + if (!new_p) { + ret = -ENOMEM; + goto out; + } + + memcpy(datablob, prep->data, datalen); + datablob[datalen] = '\0'; + ret = datablob_parse(datablob, new_p, new_o); + if (ret != Opt_update) { + ret = -EINVAL; + kzfree(new_p); + goto out; + } + + if (!new_o->keyhandle) { + ret = -EINVAL; + kzfree(new_p); + goto out; + } + + /* copy old key values, and reseal with new pcrs */ + new_p->migratable = p->migratable; + new_p->key_len = p->key_len; + memcpy(new_p->key, p->key, p->key_len); + dump_payload(p); + dump_payload(new_p); + + ret = key_seal(new_p, new_o); + if (ret < 0) { + pr_info("trusted_key: key_seal failed (%d)\n", ret); + kzfree(new_p); + goto out; + } + if (new_o->pcrlock) { + ret = pcrlock(new_o->pcrlock); + if (ret < 0) { + pr_info("trusted_key: pcrlock failed (%d)\n", ret); + kzfree(new_p); + goto out; + } + } + rcu_assign_keypointer(key, new_p); + call_rcu(&p->rcu, trusted_rcu_free); +out: + kzfree(datablob); + kzfree(new_o); + return ret; +} + +/* + * trusted_read - copy the sealed blob data to userspace in hex. + * On success, return to userspace the trusted key datablob size. + */ +static long trusted_read(const struct key *key, char *buffer, + size_t buflen) +{ + const struct trusted_key_payload *p; + char *bufp; + int i; + + p = dereference_key_locked(key); + if (!p) + return -EINVAL; + + if (buffer && buflen >= 2 * p->blob_len) { + bufp = buffer; + for (i = 0; i < p->blob_len; i++) + bufp = hex_byte_pack(bufp, p->blob[i]); + } + return 2 * p->blob_len; +} + +/* + * trusted_destroy - clear and free the key's payload + */ +static void trusted_destroy(struct key *key) +{ + kzfree(key->payload.data[0]); +} + +struct key_type key_type_trusted = { + .name = "trusted", + .instantiate = trusted_instantiate, + .update = trusted_update, + .destroy = trusted_destroy, + .describe = user_describe, + .read = trusted_read, +}; + +EXPORT_SYMBOL_GPL(key_type_trusted); + +static void trusted_shash_release(void) +{ + if (hashalg) + crypto_free_shash(hashalg); + if (hmacalg) + crypto_free_shash(hmacalg); +} + +static int __init trusted_shash_alloc(void) +{ + int ret; + + hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmacalg)) { + pr_info("trusted_key: could not allocate crypto %s\n", + hmac_alg); + return PTR_ERR(hmacalg); + } + + hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hashalg)) { + pr_info("trusted_key: could not allocate crypto %s\n", + hash_alg); + ret = PTR_ERR(hashalg); + goto hashalg_fail; + } + + return 0; + +hashalg_fail: + crypto_free_shash(hmacalg); + return ret; +} + +static int __init init_trusted(void) +{ + int ret; + + ret = trusted_shash_alloc(); + if (ret < 0) + return ret; + ret = register_key_type(&key_type_trusted); + if (ret < 0) + trusted_shash_release(); + return ret; +} + +static void __exit cleanup_trusted(void) +{ + trusted_shash_release(); + unregister_key_type(&key_type_trusted); +} + +late_initcall(init_trusted); +module_exit(cleanup_trusted); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/trusted.h b/security/keys/trusted.h new file mode 100644 index 000000000..8d5fe9eaf --- /dev/null +++ b/security/keys/trusted.h @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TRUSTED_KEY_H +#define __TRUSTED_KEY_H + +/* implementation specific TPM constants */ +#define MAX_BUF_SIZE 512 +#define TPM_GETRANDOM_SIZE 14 +#define TPM_OSAP_SIZE 36 +#define TPM_OIAP_SIZE 10 +#define TPM_SEAL_SIZE 87 +#define TPM_UNSEAL_SIZE 104 +#define TPM_SIZE_OFFSET 2 +#define TPM_RETURN_OFFSET 6 +#define TPM_DATA_OFFSET 10 + +#define LOAD32(buffer, offset) (ntohl(*(uint32_t *)&buffer[offset])) +#define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset]) +#define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset])) + +struct tpm_buf { + int len; + unsigned char data[MAX_BUF_SIZE]; +}; + +#define INIT_BUF(tb) (tb->len = 0) + +struct osapsess { + uint32_t handle; + unsigned char secret[SHA1_DIGEST_SIZE]; + unsigned char enonce[TPM_NONCE_SIZE]; +}; + +/* discrete values, but have to store in uint16_t for TPM use */ +enum { + SEAL_keytype = 1, + SRK_keytype = 4 +}; + +#define TPM_DEBUG 0 + +#if TPM_DEBUG +static inline void dump_options(struct trusted_key_options *o) +{ + pr_info("trusted_key: sealing key type %d\n", o->keytype); + pr_info("trusted_key: sealing key handle %0X\n", o->keyhandle); + pr_info("trusted_key: pcrlock %d\n", o->pcrlock); + pr_info("trusted_key: pcrinfo %d\n", o->pcrinfo_len); + print_hex_dump(KERN_INFO, "pcrinfo ", DUMP_PREFIX_NONE, + 16, 1, o->pcrinfo, o->pcrinfo_len, 0); +} + +static inline void dump_payload(struct trusted_key_payload *p) +{ + pr_info("trusted_key: key_len %d\n", p->key_len); + print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, + 16, 1, p->key, p->key_len, 0); + pr_info("trusted_key: bloblen %d\n", p->blob_len); + print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, + 16, 1, p->blob, p->blob_len, 0); + pr_info("trusted_key: migratable %d\n", p->migratable); +} + +static inline void dump_sess(struct osapsess *s) +{ + print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE, + 16, 1, &s->handle, 4, 0); + pr_info("trusted-key: secret:\n"); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, + 16, 1, &s->secret, SHA1_DIGEST_SIZE, 0); + pr_info("trusted-key: enonce:\n"); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, + 16, 1, &s->enonce, SHA1_DIGEST_SIZE, 0); +} + +static inline void dump_tpm_buf(unsigned char *buf) +{ + int len; + + pr_info("\ntrusted-key: tpm buffer\n"); + len = LOAD32(buf, TPM_SIZE_OFFSET); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, buf, len, 0); +} +#else +static inline void dump_options(struct trusted_key_options *o) +{ +} + +static inline void dump_payload(struct trusted_key_payload *p) +{ +} + +static inline void dump_sess(struct osapsess *s) +{ +} + +static inline void dump_tpm_buf(unsigned char *buf) +{ +} +#endif + +static inline void store8(struct tpm_buf *buf, const unsigned char value) +{ + buf->data[buf->len++] = value; +} + +static inline void store16(struct tpm_buf *buf, const uint16_t value) +{ + *(uint16_t *) & buf->data[buf->len] = htons(value); + buf->len += sizeof value; +} + +static inline void store32(struct tpm_buf *buf, const uint32_t value) +{ + *(uint32_t *) & buf->data[buf->len] = htonl(value); + buf->len += sizeof value; +} + +static inline void storebytes(struct tpm_buf *buf, const unsigned char *in, + const int len) +{ + memcpy(buf->data + buf->len, in, len); + buf->len += len; +} +#endif diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c new file mode 100644 index 000000000..0e723b676 --- /dev/null +++ b/security/keys/user_defined.c @@ -0,0 +1,211 @@ +/* user_defined.c: user defined key type + * + * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/seq_file.h> +#include <linux/err.h> +#include <keys/user-type.h> +#include <linux/uaccess.h> +#include "internal.h" + +static int logon_vet_description(const char *desc); + +/* + * user defined keys take an arbitrary string as the description and an + * arbitrary blob of data as the payload + */ +struct key_type key_type_user = { + .name = "user", + .preparse = user_preparse, + .free_preparse = user_free_preparse, + .instantiate = generic_key_instantiate, + .update = user_update, + .revoke = user_revoke, + .destroy = user_destroy, + .describe = user_describe, + .read = user_read, +}; + +EXPORT_SYMBOL_GPL(key_type_user); + +/* + * This key type is essentially the same as key_type_user, but it does + * not define a .read op. This is suitable for storing username and + * password pairs in the keyring that you do not want to be readable + * from userspace. + */ +struct key_type key_type_logon = { + .name = "logon", + .preparse = user_preparse, + .free_preparse = user_free_preparse, + .instantiate = generic_key_instantiate, + .update = user_update, + .revoke = user_revoke, + .destroy = user_destroy, + .describe = user_describe, + .vet_description = logon_vet_description, +}; +EXPORT_SYMBOL_GPL(key_type_logon); + +/* + * Preparse a user defined key payload + */ +int user_preparse(struct key_preparsed_payload *prep) +{ + struct user_key_payload *upayload; + size_t datalen = prep->datalen; + + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); + if (!upayload) + return -ENOMEM; + + /* attach the data */ + prep->quotalen = datalen; + prep->payload.data[0] = upayload; + upayload->datalen = datalen; + memcpy(upayload->data, prep->data, datalen); + return 0; +} +EXPORT_SYMBOL_GPL(user_preparse); + +/* + * Free a preparse of a user defined key payload + */ +void user_free_preparse(struct key_preparsed_payload *prep) +{ + kzfree(prep->payload.data[0]); +} +EXPORT_SYMBOL_GPL(user_free_preparse); + +static void user_free_payload_rcu(struct rcu_head *head) +{ + struct user_key_payload *payload; + + payload = container_of(head, struct user_key_payload, rcu); + kzfree(payload); +} + +/* + * update a user defined key + * - the key's semaphore is write-locked + */ +int user_update(struct key *key, struct key_preparsed_payload *prep) +{ + struct user_key_payload *zap = NULL; + int ret; + + /* check the quota and attach the new data */ + ret = key_payload_reserve(key, prep->datalen); + if (ret < 0) + return ret; + + /* attach the new data, displacing the old */ + key->expiry = prep->expiry; + if (key_is_positive(key)) + zap = dereference_key_locked(key); + rcu_assign_keypointer(key, prep->payload.data[0]); + prep->payload.data[0] = NULL; + + if (zap) + call_rcu(&zap->rcu, user_free_payload_rcu); + return ret; +} +EXPORT_SYMBOL_GPL(user_update); + +/* + * dispose of the links from a revoked keyring + * - called with the key sem write-locked + */ +void user_revoke(struct key *key) +{ + struct user_key_payload *upayload = user_key_payload_locked(key); + + /* clear the quota */ + key_payload_reserve(key, 0); + + if (upayload) { + rcu_assign_keypointer(key, NULL); + call_rcu(&upayload->rcu, user_free_payload_rcu); + } +} + +EXPORT_SYMBOL(user_revoke); + +/* + * dispose of the data dangling from the corpse of a user key + */ +void user_destroy(struct key *key) +{ + struct user_key_payload *upayload = key->payload.data[0]; + + kzfree(upayload); +} + +EXPORT_SYMBOL_GPL(user_destroy); + +/* + * describe the user key + */ +void user_describe(const struct key *key, struct seq_file *m) +{ + seq_puts(m, key->description); + if (key_is_positive(key)) + seq_printf(m, ": %u", key->datalen); +} + +EXPORT_SYMBOL_GPL(user_describe); + +/* + * read the key data + * - the key's semaphore is read-locked + */ +long user_read(const struct key *key, char *buffer, size_t buflen) +{ + const struct user_key_payload *upayload; + long ret; + + upayload = user_key_payload_locked(key); + ret = upayload->datalen; + + /* we can return the data as is */ + if (buffer && buflen > 0) { + if (buflen > upayload->datalen) + buflen = upayload->datalen; + + memcpy(buffer, upayload->data, buflen); + } + + return ret; +} + +EXPORT_SYMBOL_GPL(user_read); + +/* Vet the description for a "logon" key */ +static int logon_vet_description(const char *desc) +{ + char *p; + + /* require a "qualified" description string */ + p = strchr(desc, ':'); + if (!p) + return -EINVAL; + + /* also reject description with ':' as first char */ + if (p == desc) + return -EINVAL; + + return 0; +} |