diff options
Diffstat (limited to 'security/keys/dh.c')
| -rw-r--r-- | security/keys/dh.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/security/keys/dh.c b/security/keys/dh.c new file mode 100644 index 000000000..b339760a3 --- /dev/null +++ b/security/keys/dh.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Crypto operations using stored keys + * + * Copyright (c) 2016, Intel Corporation + */ + +#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 <crypto/kdf_sp800108.h> +#include <keys/user-type.h> +#include "internal.h" + +static ssize_t dh_data_from_key(key_serial_t keyid, const 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) +{ + kfree_sensitive(dh->key); + kfree_sensitive(dh->p); + kfree_sensitive(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); +} + +static int kdf_alloc(struct crypto_shash **hash, char *hashname) +{ + struct crypto_shash *tfm; + + /* 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); + } + + if (crypto_shash_digestsize(tfm) == 0) { + crypto_free_shash(tfm); + return -EINVAL; + } + + *hash = tfm; + + return 0; +} + +static void kdf_dealloc(struct crypto_shash *hash) +{ + if (hash) + crypto_free_shash(hash); +} + +static int keyctl_dh_compute_kdf(struct crypto_shash *hash, + char __user *buffer, size_t buflen, + uint8_t *kbuf, size_t kbuflen) +{ + struct kvec kbuf_iov = { .iov_base = kbuf, .iov_len = kbuflen }; + uint8_t *outbuf = NULL; + int ret; + size_t outbuf_len = roundup(buflen, crypto_shash_digestsize(hash)); + + outbuf = kmalloc(outbuf_len, GFP_KERNEL); + if (!outbuf) { + ret = -ENOMEM; + goto err; + } + + ret = crypto_kdf108_ctr_generate(hash, &kbuf_iov, 1, outbuf, outbuf_len); + if (ret) + goto err; + + ret = buflen; + if (copy_to_user(buffer, outbuf, buflen) != 0) + ret = -EFAULT; + +err: + kfree_sensitive(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 crypto_shash *hash = 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(&hash, 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(hash, buffer, buflen, outbuf, + req->dst_len + kdfcopy->otherinfolen); + } else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) { + ret = req->dst_len; + } else { + ret = -EFAULT; + } + +out6: + kpp_request_free(req); +out5: + kfree_sensitive(outbuf); +out4: + crypto_free_kpp(tfm); +out3: + kfree_sensitive(secret); +out2: + dh_free_data(&dh_inputs); +out1: + kdf_dealloc(hash); + 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); +} |