| /* Basic authentication token and access key management |
| * |
| * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/poison.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/security.h> |
| #include <linux/workqueue.h> |
| #include <linux/random.h> |
| #include <linux/err.h> |
| #include "internal.h" |
| |
| struct kmem_cache *key_jar; |
| struct rb_root key_serial_tree; /* tree of keys indexed by serial */ |
| DEFINE_SPINLOCK(key_serial_lock); |
| |
| struct rb_root key_user_tree; /* tree of quota records indexed by UID */ |
| DEFINE_SPINLOCK(key_user_lock); |
| |
| unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */ |
| unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */ |
| unsigned int key_quota_maxkeys = 200; /* general key count quota */ |
| unsigned int key_quota_maxbytes = 20000; /* general key space quota */ |
| |
| static LIST_HEAD(key_types_list); |
| static DECLARE_RWSEM(key_types_sem); |
| |
| /* We serialise key instantiation and link */ |
| DEFINE_MUTEX(key_construction_mutex); |
| |
| #ifdef KEY_DEBUGGING |
| void __key_check(const struct key *key) |
| { |
| printk("__key_check: key %p {%08x} should be {%08x}\n", |
| key, key->magic, KEY_DEBUG_MAGIC); |
| BUG(); |
| } |
| #endif |
| |
| /* |
| * Get the key quota record for a user, allocating a new record if one doesn't |
| * already exist. |
| */ |
| struct key_user *key_user_lookup(kuid_t uid) |
| { |
| struct key_user *candidate = NULL, *user; |
| struct rb_node *parent = NULL; |
| struct rb_node **p; |
| |
| try_again: |
| p = &key_user_tree.rb_node; |
| spin_lock(&key_user_lock); |
| |
| /* search the tree for a user record with a matching UID */ |
| while (*p) { |
| parent = *p; |
| user = rb_entry(parent, struct key_user, node); |
| |
| if (uid_lt(uid, user->uid)) |
| p = &(*p)->rb_left; |
| else if (uid_gt(uid, user->uid)) |
| p = &(*p)->rb_right; |
| else |
| goto found; |
| } |
| |
| /* if we get here, we failed to find a match in the tree */ |
| if (!candidate) { |
| /* allocate a candidate user record if we don't already have |
| * one */ |
| spin_unlock(&key_user_lock); |
| |
| user = NULL; |
| candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); |
| if (unlikely(!candidate)) |
| goto out; |
| |
| /* the allocation may have scheduled, so we need to repeat the |
| * search lest someone else added the record whilst we were |
| * asleep */ |
| goto try_again; |
| } |
| |
| /* if we get here, then the user record still hadn't appeared on the |
| * second pass - so we use the candidate record */ |
| atomic_set(&candidate->usage, 1); |
| atomic_set(&candidate->nkeys, 0); |
| atomic_set(&candidate->nikeys, 0); |
| candidate->uid = uid; |
| candidate->qnkeys = 0; |
| candidate->qnbytes = 0; |
| spin_lock_init(&candidate->lock); |
| mutex_init(&candidate->cons_lock); |
| |
| rb_link_node(&candidate->node, parent, p); |
| rb_insert_color(&candidate->node, &key_user_tree); |
| spin_unlock(&key_user_lock); |
| user = candidate; |
| goto out; |
| |
| /* okay - we found a user record for this UID */ |
| found: |
| atomic_inc(&user->usage); |
| spin_unlock(&key_user_lock); |
| kfree(candidate); |
| out: |
| return user; |
| } |
| |
| /* |
| * Dispose of a user structure |
| */ |
| void key_user_put(struct key_user *user) |
| { |
| if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { |
| rb_erase(&user->node, &key_user_tree); |
| spin_unlock(&key_user_lock); |
| |
| kfree(user); |
| } |
| } |
| |
| /* |
| * Allocate a serial number for a key. These are assigned randomly to avoid |
| * security issues through covert channel problems. |
| */ |
| static inline void key_alloc_serial(struct key *key) |
| { |
| struct rb_node *parent, **p; |
| struct key *xkey; |
| |
| /* propose a random serial number and look for a hole for it in the |
| * serial number tree */ |
| do { |
| get_random_bytes(&key->serial, sizeof(key->serial)); |
| |
| key->serial >>= 1; /* negative numbers are not permitted */ |
| } while (key->serial < 3); |
| |
| spin_lock(&key_serial_lock); |
| |
| attempt_insertion: |
| parent = NULL; |
| p = &key_serial_tree.rb_node; |
| |
| while (*p) { |
| parent = *p; |
| xkey = rb_entry(parent, struct key, serial_node); |
| |
| if (key->serial < xkey->serial) |
| p = &(*p)->rb_left; |
| else if (key->serial > xkey->serial) |
| p = &(*p)->rb_right; |
| else |
| goto serial_exists; |
| } |
| |
| /* we've found a suitable hole - arrange for this key to occupy it */ |
| rb_link_node(&key->serial_node, parent, p); |
| rb_insert_color(&key->serial_node, &key_serial_tree); |
| |
| spin_unlock(&key_serial_lock); |
| return; |
| |
| /* we found a key with the proposed serial number - walk the tree from |
| * that point looking for the next unused serial number */ |
| serial_exists: |
| for (;;) { |
| key->serial++; |
| if (key->serial < 3) { |
| key->serial = 3; |
| goto attempt_insertion; |
| } |
| |
| parent = rb_next(parent); |
| if (!parent) |
| goto attempt_insertion; |
| |
| xkey = rb_entry(parent, struct key, serial_node); |
| if (key->serial < xkey->serial) |
| goto attempt_insertion; |
| } |
| } |
| |
| /** |
| * key_alloc - Allocate a key of the specified type. |
| * @type: The type of key to allocate. |
| * @desc: The key description to allow the key to be searched out. |
| * @uid: The owner of the new key. |
| * @gid: The group ID for the new key's group permissions. |
| * @cred: The credentials specifying UID namespace. |
| * @perm: The permissions mask of the new key. |
| * @flags: Flags specifying quota properties. |
| * |
| * Allocate a key of the specified type with the attributes given. The key is |
| * returned in an uninstantiated state and the caller needs to instantiate the |
| * key before returning. |
| * |
| * The user's key count quota is updated to reflect the creation of the key and |
| * the user's key data quota has the default for the key type reserved. The |
| * instantiation function should amend this as necessary. If insufficient |
| * quota is available, -EDQUOT will be returned. |
| * |
| * The LSM security modules can prevent a key being created, in which case |
| * -EACCES will be returned. |
| * |
| * Returns a pointer to the new key if successful and an error code otherwise. |
| * |
| * Note that the caller needs to ensure the key type isn't uninstantiated. |
| * Internally this can be done by locking key_types_sem. Externally, this can |
| * be done by either never unregistering the key type, or making sure |
| * key_alloc() calls don't race with module unloading. |
| */ |
| struct key *key_alloc(struct key_type *type, const char *desc, |
| kuid_t uid, kgid_t gid, const struct cred *cred, |
| key_perm_t perm, unsigned long flags) |
| { |
| struct key_user *user = NULL; |
| struct key *key; |
| size_t desclen, quotalen; |
| int ret; |
| |
| key = ERR_PTR(-EINVAL); |
| if (!desc || !*desc) |
| goto error; |
| |
| if (type->vet_description) { |
| ret = type->vet_description(desc); |
| if (ret < 0) { |
| key = ERR_PTR(ret); |
| goto error; |
| } |
| } |
| |
| desclen = strlen(desc) + 1; |
| quotalen = desclen + type->def_datalen; |
| |
| /* get hold of the key tracking for this user */ |
| user = key_user_lookup(uid); |
| if (!user) |
| goto no_memory_1; |
| |
| /* check that the user's quota permits allocation of another key and |
| * its description */ |
| if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
| unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? |
| key_quota_root_maxkeys : key_quota_maxkeys; |
| unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? |
| key_quota_root_maxbytes : key_quota_maxbytes; |
| |
| spin_lock(&user->lock); |
| if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
| if (user->qnkeys + 1 >= maxkeys || |
| user->qnbytes + quotalen >= maxbytes || |
| user->qnbytes + quotalen < user->qnbytes) |
| goto no_quota; |
| } |
| |
| user->qnkeys++; |
| user->qnbytes += quotalen; |
| spin_unlock(&user->lock); |
| } |
| |
| /* allocate and initialise the key and its description */ |
| key = kmem_cache_alloc(key_jar, GFP_KERNEL); |
| if (!key) |
| goto no_memory_2; |
| |
| if (desc) { |
| key->description = kmemdup(desc, desclen, GFP_KERNEL); |
| if (!key->description) |
| goto no_memory_3; |
| } |
| |
| atomic_set(&key->usage, 1); |
| init_rwsem(&key->sem); |
| lockdep_set_class(&key->sem, &type->lock_class); |
| key->type = type; |
| key->user = user; |
| key->quotalen = quotalen; |
| key->datalen = type->def_datalen; |
| key->uid = uid; |
| key->gid = gid; |
| key->perm = perm; |
| key->flags = 0; |
| key->expiry = 0; |
| key->payload.data = NULL; |
| key->security = NULL; |
| |
| if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
| key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
| |
| memset(&key->type_data, 0, sizeof(key->type_data)); |
| |
| #ifdef KEY_DEBUGGING |
| key->magic = KEY_DEBUG_MAGIC; |
| #endif |
| |
| /* let the security module know about the key */ |
| ret = security_key_alloc(key, cred, flags); |
| if (ret < 0) |
| goto security_error; |
| |
| /* publish the key by giving it a serial number */ |
| atomic_inc(&user->nkeys); |
| key_alloc_serial(key); |
| |
| error: |
| return key; |
| |
| security_error: |
| kfree(key->description); |
| kmem_cache_free(key_jar, key); |
| if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
| spin_lock(&user->lock); |
| user->qnkeys--; |
| user->qnbytes -= quotalen; |
| spin_unlock(&user->lock); |
| } |
| key_user_put(user); |
| key = ERR_PTR(ret); |
| goto error; |
| |
| no_memory_3: |
| kmem_cache_free(key_jar, key); |
| no_memory_2: |
| if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
| spin_lock(&user->lock); |
| user->qnkeys--; |
| user->qnbytes -= quotalen; |
| spin_unlock(&user->lock); |
| } |
| key_user_put(user); |
| no_memory_1: |
| key = ERR_PTR(-ENOMEM); |
| goto error; |
| |
| no_quota: |
| spin_unlock(&user->lock); |
| key_user_put(user); |
| key = ERR_PTR(-EDQUOT); |
| goto error; |
| } |
| EXPORT_SYMBOL(key_alloc); |
| |
| /** |
| * key_payload_reserve - Adjust data quota reservation for the key's payload |
| * @key: The key to make the reservation for. |
| * @datalen: The amount of data payload the caller now wants. |
| * |
| * Adjust the amount of the owning user's key data quota that a key reserves. |
| * If the amount is increased, then -EDQUOT may be returned if there isn't |
| * enough free quota available. |
| * |
| * If successful, 0 is returned. |
| */ |
| int key_payload_reserve(struct key *key, size_t datalen) |
| { |
| int delta = (int)datalen - key->datalen; |
| int ret = 0; |
| |
| key_check(key); |
| |
| /* contemplate the quota adjustment */ |
| if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
| unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ? |
| key_quota_root_maxbytes : key_quota_maxbytes; |
| |
| spin_lock(&key->user->lock); |
| |
| if (delta > 0 && |
| (key->user->qnbytes + delta >= maxbytes || |
| key->user->qnbytes + delta < key->user->qnbytes)) { |
| ret = -EDQUOT; |
| } |
| else { |
| key->user->qnbytes += delta; |
| key->quotalen += delta; |
| } |
| spin_unlock(&key->user->lock); |
| } |
| |
| /* change the recorded data length if that didn't generate an error */ |
| if (ret == 0) |
| key->datalen = datalen; |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(key_payload_reserve); |
| |
| /* |
| * 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, |
| const void *data, |
| size_t datalen, |
| struct key *keyring, |
| struct key *authkey, |
| unsigned long *_prealloc) |
| { |
| int ret, awaken; |
| |
| key_check(key); |
| key_check(keyring); |
| |
| awaken = 0; |
| ret = -EBUSY; |
| |
| mutex_lock(&key_construction_mutex); |
| |
| /* can't instantiate twice */ |
| if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
| /* instantiate the key */ |
| ret = key->type->instantiate(key, data, datalen); |
| |
| if (ret == 0) { |
| /* mark the key as being instantiated */ |
| atomic_inc(&key->user->nikeys); |
| set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
| |
| if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
| awaken = 1; |
| |
| /* and link it into the destination keyring */ |
| if (keyring) |
| __key_link(keyring, key, _prealloc); |
| |
| /* disable the authorisation key */ |
| if (authkey) |
| key_revoke(authkey); |
| } |
| } |
| |
| 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) |
| { |
| unsigned long prealloc; |
| int ret; |
| |
| if (keyring) { |
| ret = __key_link_begin(keyring, key->type, key->description, |
| &prealloc); |
| if (ret < 0) |
| return ret; |
| } |
| |
| ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey, |
| &prealloc); |
| |
| if (keyring) |
| __key_link_end(keyring, key->type, prealloc); |
| |
| 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) |
| { |
| unsigned long prealloc; |
| struct timespec now; |
| int ret, awaken, link_ret = 0; |
| |
| key_check(key); |
| key_check(keyring); |
| |
| awaken = 0; |
| ret = -EBUSY; |
| |
| if (keyring) |
| link_ret = __key_link_begin(keyring, key->type, |
| key->description, &prealloc); |
| |
| mutex_lock(&key_construction_mutex); |
| |
| /* can't instantiate twice */ |
| if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
| /* mark the key as being negatively instantiated */ |
| atomic_inc(&key->user->nikeys); |
| set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
| set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
| key->type_data.reject_error = -error; |
| now = current_kernel_time(); |
| key->expiry = now.tv_sec + 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, &prealloc); |
| |
| /* disable the authorisation key */ |
| if (authkey) |
| key_revoke(authkey); |
| } |
| |
| mutex_unlock(&key_construction_mutex); |
| |
| if (keyring) |
| __key_link_end(keyring, key->type, prealloc); |
| |
| /* 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 (atomic_dec_and_test(&key->usage)) |
| queue_work(system_nrt_wq, &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: |
| /* pretend it doesn't exist if it is awaiting deletion */ |
| if (atomic_read(&key->usage) == 0) |
| goto not_found; |
| |
| /* this races with key_put(), but that doesn't matter since key_put() |
| * doesn't actually change the key |
| */ |
| atomic_inc(&key->usage); |
| |
| 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) |
| { |
| struct timespec now; |
| time_t expiry = 0; |
| |
| /* make the changes with the locks held to prevent races */ |
| down_write(&key->sem); |
| |
| if (timeout > 0) { |
| now = current_kernel_time(); |
| expiry = now.tv_sec + 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, |
| const void *payload, size_t plen) |
| { |
| 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_WRITE); |
| if (ret < 0) |
| goto error; |
| |
| ret = -EEXIST; |
| if (!key->type->update) |
| goto error; |
| |
| down_write(&key->sem); |
| |
| ret = key->type->update(key, payload, plen); |
| if (ret == 0) |
| /* updating a negative key instantiates it */ |
| clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
| |
| 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) |
| { |
| unsigned long prealloc; |
| const struct cred *cred = current_cred(); |
| struct key_type *ktype; |
| struct key *keyring, *key = NULL; |
| key_ref_t key_ref; |
| int ret; |
| |
| /* look up the key type to see if it's one of the registered kernel |
| * types */ |
| ktype = key_type_lookup(type); |
| if (IS_ERR(ktype)) { |
| key_ref = ERR_PTR(-ENODEV); |
| goto error; |
| } |
| |
| key_ref = ERR_PTR(-EINVAL); |
| if (!ktype->match || !ktype->instantiate) |
| goto error_2; |
| |
| keyring = key_ref_to_ptr(keyring_ref); |
| |
| key_check(keyring); |
| |
| key_ref = ERR_PTR(-ENOTDIR); |
| if (keyring->type != &key_type_keyring) |
| goto error_2; |
| |
| ret = __key_link_begin(keyring, ktype, description, &prealloc); |
| if (ret < 0) |
| goto error_2; |
| |
| /* if we're going to allocate a new key, we're going to have |
| * to modify the keyring */ |
| ret = key_permission(keyring_ref, KEY_WRITE); |
| if (ret < 0) { |
| key_ref = ERR_PTR(ret); |
| goto error_3; |
| } |
| |
| /* 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 (ktype->update) { |
| key_ref = __keyring_search_one(keyring_ref, ktype, description, |
| 0); |
| if (!IS_ERR(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 | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; |
| |
| if (ktype->read) |
| perm |= KEY_POS_READ | KEY_USR_READ; |
| |
| if (ktype == &key_type_keyring || ktype->update) |
| perm |= KEY_USR_WRITE; |
| } |
| |
| /* allocate a new key */ |
| key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred, |
| perm, flags); |
| if (IS_ERR(key)) { |
| key_ref = ERR_CAST(key); |
| goto error_3; |
| } |
| |
| /* instantiate it and link it into the target keyring */ |
| ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL, |
| &prealloc); |
| if (ret < 0) { |
| key_put(key); |
| key_ref = ERR_PTR(ret); |
| goto error_3; |
| } |
| |
| key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
| |
| error_3: |
| __key_link_end(keyring, ktype, prealloc); |
| error_2: |
| key_type_put(ktype); |
| 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, ktype, prealloc); |
| key_type_put(ktype); |
| |
| key_ref = __key_update(key_ref, payload, plen); |
| goto error; |
| } |
| 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 *key = key_ref_to_ptr(key_ref); |
| int ret; |
| |
| key_check(key); |
| |
| /* the key must be writable */ |
| ret = key_permission(key_ref, KEY_WRITE); |
| if (ret < 0) |
| goto error; |
| |
| /* attempt to update it if supported */ |
| ret = -EOPNOTSUPP; |
| if (key->type->update) { |
| down_write(&key->sem); |
| |
| ret = key->type->update(key, payload, plen); |
| if (ret == 0) |
| /* updating a negative key instantiates it */ |
| clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
| |
| up_write(&key->sem); |
| } |
| |
| error: |
| 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) |
| { |
| struct timespec now; |
| time_t time; |
| |
| key_check(key); |
| |
| /* make sure no one's trying to change or use the key when we mark it |
| * - we tell lockdep that we might nest because we might be revoking an |
| * authorisation key whilst holding the sem on a key we've just |
| * instantiated |
| */ |
| down_write_nested(&key->sem, 1); |
| if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) && |
| key->type->revoke) |
| key->type->revoke(key); |
| |
| /* set the death time to no more than the expiry time */ |
| now = current_kernel_time(); |
| time = now.tv_sec; |
| if (key->revoked_at == 0 || key->revoked_at > time) { |
| key->revoked_at = time; |
| key_schedule_gc(key->revoked_at + key_gc_delay); |
| } |
| |
| up_write(&key->sem); |
| } |
| EXPORT_SYMBOL(key_revoke); |
| |
| /** |
| * key_invalidate - Invalidate a key. |
| * @key: The key to be invalidated. |
| * |
| * Mark a key as being invalidated and have it cleaned up immediately. The key |
| * is ignored by all searches and other operations from this point. |
| */ |
| void key_invalidate(struct key *key) |
| { |
| kenter("%d", key_serial(key)); |
| |
| key_check(key); |
| |
| if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) { |
| down_write_nested(&key->sem, 1); |
| if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) |
| key_schedule_gc_links(); |
| up_write(&key->sem); |
| } |
| } |
| EXPORT_SYMBOL(key_invalidate); |
| |
| /** |
| * register_key_type - Register a type of key. |
| * @ktype: The new key type. |
| * |
| * Register a new key type. |
| * |
| * Returns 0 on success or -EEXIST if a type of this name already exists. |
| */ |
| int register_key_type(struct key_type *ktype) |
| { |
| struct key_type *p; |
| int ret; |
| |
| memset(&ktype->lock_class, 0, sizeof(ktype->lock_class)); |
| |
| ret = -EEXIST; |
| down_write(&key_types_sem); |
| |
| /* disallow key types with the same name */ |
| list_for_each_entry(p, &key_types_list, link) { |
| if (strcmp(p->name, ktype->name) == 0) |
| goto out; |
| } |
| |
| /* store the type */ |
| list_add(&ktype->link, &key_types_list); |
| |
| pr_notice("Key type %s registered\n", ktype->name); |
| ret = 0; |
| |
| out: |
| up_write(&key_types_sem); |
| return ret; |
| } |
| EXPORT_SYMBOL(register_key_type); |
| |
| /** |
| * unregister_key_type - Unregister a type of key. |
| * @ktype: The key type. |
| * |
| * Unregister a key type and mark all the extant keys of this type as dead. |
| * Those keys of this type are then destroyed to get rid of their payloads and |
| * they and their links will be garbage collected as soon as possible. |
| */ |
| void unregister_key_type(struct key_type *ktype) |
| { |
| down_write(&key_types_sem); |
| list_del_init(&ktype->link); |
| downgrade_write(&key_types_sem); |
| key_gc_keytype(ktype); |
| pr_notice("Key type %s unregistered\n", ktype->name); |
| up_read(&key_types_sem); |
| } |
| EXPORT_SYMBOL(unregister_key_type); |
| |
| /* |
| * Initialise the key management state. |
| */ |
| void __init key_init(void) |
| { |
| /* allocate a slab in which we can store keys */ |
| key_jar = kmem_cache_create("key_jar", sizeof(struct key), |
| 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
| |
| /* add the special key types */ |
| list_add_tail(&key_type_keyring.link, &key_types_list); |
| list_add_tail(&key_type_dead.link, &key_types_list); |
| list_add_tail(&key_type_user.link, &key_types_list); |
| list_add_tail(&key_type_logon.link, &key_types_list); |
| |
| /* record the root user tracking */ |
| rb_link_node(&root_key_user.node, |
| NULL, |
| &key_user_tree.rb_node); |
| |
| rb_insert_color(&root_key_user.node, |
| &key_user_tree); |
| } |