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1220 lines
32 KiB
1220 lines
32 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* Basic authentication token and access key management |
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* |
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* Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
|
|
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#include <linux/export.h> |
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#include <linux/init.h> |
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#include <linux/poison.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/security.h> |
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#include <linux/workqueue.h> |
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#include <linux/random.h> |
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#include <linux/ima.h> |
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#include <linux/err.h> |
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#include "internal.h" |
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|
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struct kmem_cache *key_jar; |
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struct rb_root key_serial_tree; /* tree of keys indexed by serial */ |
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DEFINE_SPINLOCK(key_serial_lock); |
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|
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struct rb_root key_user_tree; /* tree of quota records indexed by UID */ |
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DEFINE_SPINLOCK(key_user_lock); |
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|
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unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */ |
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unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */ |
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unsigned int key_quota_maxkeys = 200; /* general key count quota */ |
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unsigned int key_quota_maxbytes = 20000; /* general key space quota */ |
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|
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static LIST_HEAD(key_types_list); |
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static DECLARE_RWSEM(key_types_sem); |
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|
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/* We serialise key instantiation and link */ |
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DEFINE_MUTEX(key_construction_mutex); |
|
|
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#ifdef KEY_DEBUGGING |
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void __key_check(const struct key *key) |
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{ |
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printk("__key_check: key %p {%08x} should be {%08x}\n", |
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key, key->magic, KEY_DEBUG_MAGIC); |
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BUG(); |
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} |
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#endif |
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|
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/* |
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* Get the key quota record for a user, allocating a new record if one doesn't |
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* already exist. |
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*/ |
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struct key_user *key_user_lookup(kuid_t uid) |
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{ |
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struct key_user *candidate = NULL, *user; |
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struct rb_node *parent, **p; |
|
|
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try_again: |
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parent = NULL; |
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p = &key_user_tree.rb_node; |
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spin_lock(&key_user_lock); |
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|
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/* search the tree for a user record with a matching UID */ |
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while (*p) { |
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parent = *p; |
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user = rb_entry(parent, struct key_user, node); |
|
|
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if (uid_lt(uid, user->uid)) |
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p = &(*p)->rb_left; |
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else if (uid_gt(uid, user->uid)) |
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p = &(*p)->rb_right; |
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else |
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goto found; |
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} |
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|
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/* if we get here, we failed to find a match in the tree */ |
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if (!candidate) { |
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/* allocate a candidate user record if we don't already have |
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* one */ |
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spin_unlock(&key_user_lock); |
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|
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user = NULL; |
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candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); |
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if (unlikely(!candidate)) |
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goto out; |
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|
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/* the allocation may have scheduled, so we need to repeat the |
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* search lest someone else added the record whilst we were |
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* asleep */ |
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goto try_again; |
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} |
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|
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/* if we get here, then the user record still hadn't appeared on the |
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* second pass - so we use the candidate record */ |
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refcount_set(&candidate->usage, 1); |
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atomic_set(&candidate->nkeys, 0); |
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atomic_set(&candidate->nikeys, 0); |
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candidate->uid = uid; |
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candidate->qnkeys = 0; |
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candidate->qnbytes = 0; |
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spin_lock_init(&candidate->lock); |
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mutex_init(&candidate->cons_lock); |
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|
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rb_link_node(&candidate->node, parent, p); |
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rb_insert_color(&candidate->node, &key_user_tree); |
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spin_unlock(&key_user_lock); |
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user = candidate; |
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goto out; |
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|
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/* okay - we found a user record for this UID */ |
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found: |
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refcount_inc(&user->usage); |
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spin_unlock(&key_user_lock); |
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kfree(candidate); |
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out: |
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return user; |
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} |
|
|
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/* |
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* Dispose of a user structure |
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*/ |
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void key_user_put(struct key_user *user) |
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{ |
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if (refcount_dec_and_lock(&user->usage, &key_user_lock)) { |
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rb_erase(&user->node, &key_user_tree); |
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spin_unlock(&key_user_lock); |
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|
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kfree(user); |
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} |
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} |
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|
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/* |
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* Allocate a serial number for a key. These are assigned randomly to avoid |
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* security issues through covert channel problems. |
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*/ |
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static inline void key_alloc_serial(struct key *key) |
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{ |
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struct rb_node *parent, **p; |
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struct key *xkey; |
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|
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/* propose a random serial number and look for a hole for it in the |
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* serial number tree */ |
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do { |
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get_random_bytes(&key->serial, sizeof(key->serial)); |
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|
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key->serial >>= 1; /* negative numbers are not permitted */ |
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} while (key->serial < 3); |
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|
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spin_lock(&key_serial_lock); |
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|
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attempt_insertion: |
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parent = NULL; |
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p = &key_serial_tree.rb_node; |
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|
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while (*p) { |
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parent = *p; |
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xkey = rb_entry(parent, struct key, serial_node); |
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|
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if (key->serial < xkey->serial) |
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p = &(*p)->rb_left; |
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else if (key->serial > xkey->serial) |
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p = &(*p)->rb_right; |
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else |
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goto serial_exists; |
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} |
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|
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/* we've found a suitable hole - arrange for this key to occupy it */ |
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rb_link_node(&key->serial_node, parent, p); |
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rb_insert_color(&key->serial_node, &key_serial_tree); |
|
|
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spin_unlock(&key_serial_lock); |
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return; |
|
|
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/* we found a key with the proposed serial number - walk the tree from |
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* that point looking for the next unused serial number */ |
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serial_exists: |
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for (;;) { |
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key->serial++; |
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if (key->serial < 3) { |
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key->serial = 3; |
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goto attempt_insertion; |
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} |
|
|
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parent = rb_next(parent); |
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if (!parent) |
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goto attempt_insertion; |
|
|
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xkey = rb_entry(parent, struct key, serial_node); |
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if (key->serial < xkey->serial) |
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goto attempt_insertion; |
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} |
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} |
|
|
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/** |
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* key_alloc - Allocate a key of the specified type. |
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* @type: The type of key to allocate. |
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* @desc: The key description to allow the key to be searched out. |
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* @uid: The owner of the new key. |
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* @gid: The group ID for the new key's group permissions. |
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* @cred: The credentials specifying UID namespace. |
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* @perm: The permissions mask of the new key. |
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* @flags: Flags specifying quota properties. |
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* @restrict_link: Optional link restriction for new keyrings. |
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* |
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* Allocate a key of the specified type with the attributes given. The key is |
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* returned in an uninstantiated state and the caller needs to instantiate the |
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* key before returning. |
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* |
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* The restrict_link structure (if not NULL) will be freed when the |
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* keyring is destroyed, so it must be dynamically allocated. |
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* |
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* The user's key count quota is updated to reflect the creation of the key and |
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* the user's key data quota has the default for the key type reserved. The |
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* instantiation function should amend this as necessary. If insufficient |
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* quota is available, -EDQUOT will be returned. |
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* |
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* The LSM security modules can prevent a key being created, in which case |
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* -EACCES will be returned. |
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* |
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* Returns a pointer to the new key if successful and an error code otherwise. |
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* |
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* Note that the caller needs to ensure the key type isn't uninstantiated. |
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* Internally this can be done by locking key_types_sem. Externally, this can |
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* be done by either never unregistering the key type, or making sure |
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* key_alloc() calls don't race with module unloading. |
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*/ |
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struct key *key_alloc(struct key_type *type, const char *desc, |
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kuid_t uid, kgid_t gid, const struct cred *cred, |
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key_perm_t perm, unsigned long flags, |
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struct key_restriction *restrict_link) |
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{ |
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struct key_user *user = NULL; |
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struct key *key; |
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size_t desclen, quotalen; |
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int ret; |
|
|
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key = ERR_PTR(-EINVAL); |
|
if (!desc || !*desc) |
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goto error; |
|
|
|
if (type->vet_description) { |
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ret = type->vet_description(desc); |
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if (ret < 0) { |
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key = ERR_PTR(ret); |
|
goto error; |
|
} |
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} |
|
|
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desclen = strlen(desc); |
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quotalen = desclen + 1 + type->def_datalen; |
|
|
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/* get hold of the key tracking for this user */ |
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user = key_user_lookup(uid); |
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if (!user) |
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goto no_memory_1; |
|
|
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/* check that the user's quota permits allocation of another key and |
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* its description */ |
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
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unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? |
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key_quota_root_maxkeys : key_quota_maxkeys; |
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unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? |
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key_quota_root_maxbytes : key_quota_maxbytes; |
|
|
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spin_lock(&user->lock); |
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if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
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if (user->qnkeys + 1 > maxkeys || |
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user->qnbytes + quotalen > maxbytes || |
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user->qnbytes + quotalen < user->qnbytes) |
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goto no_quota; |
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} |
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|
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user->qnkeys++; |
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user->qnbytes += quotalen; |
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spin_unlock(&user->lock); |
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} |
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|
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/* allocate and initialise the key and its description */ |
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key = kmem_cache_zalloc(key_jar, GFP_KERNEL); |
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if (!key) |
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goto no_memory_2; |
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|
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key->index_key.desc_len = desclen; |
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key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL); |
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if (!key->index_key.description) |
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goto no_memory_3; |
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key->index_key.type = type; |
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key_set_index_key(&key->index_key); |
|
|
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refcount_set(&key->usage, 1); |
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init_rwsem(&key->sem); |
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lockdep_set_class(&key->sem, &type->lock_class); |
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key->user = user; |
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key->quotalen = quotalen; |
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key->datalen = type->def_datalen; |
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key->uid = uid; |
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key->gid = gid; |
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key->perm = perm; |
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key->restrict_link = restrict_link; |
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key->last_used_at = ktime_get_real_seconds(); |
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|
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
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key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
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if (flags & KEY_ALLOC_BUILT_IN) |
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key->flags |= 1 << KEY_FLAG_BUILTIN; |
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if (flags & KEY_ALLOC_UID_KEYRING) |
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key->flags |= 1 << KEY_FLAG_UID_KEYRING; |
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if (flags & KEY_ALLOC_SET_KEEP) |
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key->flags |= 1 << KEY_FLAG_KEEP; |
|
|
|
#ifdef KEY_DEBUGGING |
|
key->magic = KEY_DEBUG_MAGIC; |
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#endif |
|
|
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/* let the security module know about the key */ |
|
ret = security_key_alloc(key, cred, flags); |
|
if (ret < 0) |
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goto security_error; |
|
|
|
/* publish the key by giving it a serial number */ |
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refcount_inc(&key->domain_tag->usage); |
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atomic_inc(&user->nkeys); |
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key_alloc_serial(key); |
|
|
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error: |
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return key; |
|
|
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security_error: |
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kfree(key->description); |
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kmem_cache_free(key_jar, key); |
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
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spin_lock(&user->lock); |
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user->qnkeys--; |
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user->qnbytes -= quotalen; |
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spin_unlock(&user->lock); |
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} |
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key_user_put(user); |
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key = ERR_PTR(ret); |
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goto error; |
|
|
|
no_memory_3: |
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kmem_cache_free(key_jar, key); |
|
no_memory_2: |
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if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
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spin_lock(&user->lock); |
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user->qnkeys--; |
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user->qnbytes -= quotalen; |
|
spin_unlock(&user->lock); |
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} |
|
key_user_put(user); |
|
no_memory_1: |
|
key = ERR_PTR(-ENOMEM); |
|
goto error; |
|
|
|
no_quota: |
|
spin_unlock(&user->lock); |
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key_user_put(user); |
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key = ERR_PTR(-EDQUOT); |
|
goto error; |
|
} |
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EXPORT_SYMBOL(key_alloc); |
|
|
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/** |
|
* 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); |
|
notify_key(key, NOTIFY_KEY_INSTANTIATED, 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(keyring, key, _edit); |
|
} |
|
|
|
/* disable the authorisation key */ |
|
if (authkey) |
|
key_invalidate(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 = NULL; |
|
int ret; |
|
|
|
memset(&prep, 0, sizeof(prep)); |
|
prep.orig_description = key->description; |
|
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_lock(keyring, &key->index_key); |
|
if (ret < 0) |
|
goto error; |
|
|
|
ret = __key_link_begin(keyring, &key->index_key, &edit); |
|
if (ret < 0) |
|
goto error_link_end; |
|
|
|
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 = NULL; |
|
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_lock(keyring, &key->index_key); |
|
if (link_ret == 0) { |
|
link_ret = __key_link_begin(keyring, &key->index_key, &edit); |
|
if (link_ret < 0) |
|
__key_link_end(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); |
|
notify_key(key, NOTIFY_KEY_INSTANTIATED, -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(keyring, key, &edit); |
|
|
|
/* disable the authorisation key */ |
|
if (authkey) |
|
key_invalidate(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); |
|
notify_key(key, NOTIFY_KEY_UPDATED, 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 = NULL; |
|
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.orig_description = description; |
|
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); |
|
key_set_index_key(&index_key); |
|
|
|
ret = __key_link_lock(keyring, &index_key); |
|
if (ret < 0) { |
|
key_ref = ERR_PTR(ret); |
|
goto error_free_prep; |
|
} |
|
|
|
ret = __key_link_begin(keyring, &index_key, &edit); |
|
if (ret < 0) { |
|
key_ref = ERR_PTR(ret); |
|
goto error_link_end; |
|
} |
|
|
|
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; |
|
} |
|
|
|
ima_post_key_create_or_update(keyring, key, payload, plen, |
|
flags, true); |
|
|
|
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); |
|
|
|
if (!IS_ERR(key_ref)) |
|
ima_post_key_create_or_update(keyring, key, |
|
payload, plen, |
|
flags, false); |
|
|
|
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); |
|
notify_key(key, NOTIFY_KEY_UPDATED, 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)) { |
|
notify_key(key, NOTIFY_KEY_REVOKED, 0); |
|
if (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)) { |
|
notify_key(key, NOTIFY_KEY_INVALIDATED, 0); |
|
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); |
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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); |
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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); |
|
}
|
|
|