summaryrefslogtreecommitdiffstats
path: root/security/keys/keyctl.c
diff options
context:
space:
mode:
Diffstat (limited to 'security/keys/keyctl.c')
-rw-r--r--security/keys/keyctl.c1817
1 files changed, 1817 insertions, 0 deletions
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;
+ }
+}