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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/export.h>#include <linux/init.h>#include <linux/poison.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/security.h>#include <linux/workqueue.h>#include <linux/random.h>#include <linux/err.h>#include "internal.h"
struct kmem_cache *key_jar;struct rb_root key_serial_tree; /* tree of keys indexed by serial */DEFINE_SPINLOCK(key_serial_lock);
struct rb_root key_user_tree; /* tree of quota records indexed by UID */DEFINE_SPINLOCK(key_user_lock);
unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */unsigned int key_quota_maxkeys = 200; /* general key count quota */unsigned int key_quota_maxbytes = 20000; /* general key space quota */
static LIST_HEAD(key_types_list);static DECLARE_RWSEM(key_types_sem);
/* We serialise key instantiation and link */DEFINE_MUTEX(key_construction_mutex);
#ifdef KEY_DEBUGGINGvoid __key_check(const struct key *key){ printk("__key_check: key %p {%08x} should be {%08x}\n", key, key->magic, KEY_DEBUG_MAGIC); BUG();}#endif
/* * Get the key quota record for a user, allocating a new record if one doesn't * already exist. */struct key_user *key_user_lookup(kuid_t uid){ struct key_user *candidate = NULL, *user; struct rb_node *parent, **p;
try_again: parent = NULL; p = &key_user_tree.rb_node; spin_lock(&key_user_lock);
/* search the tree for a user record with a matching UID */ while (*p) { parent = *p; user = rb_entry(parent, struct key_user, node);
if (uid_lt(uid, user->uid)) p = &(*p)->rb_left; else if (uid_gt(uid, user->uid)) p = &(*p)->rb_right; else goto found; }
/* if we get here, we failed to find a match in the tree */ if (!candidate) { /* allocate a candidate user record if we don't already have * one */ spin_unlock(&key_user_lock);
user = NULL; candidate = kmalloc_obj(struct key_user); if (unlikely(!candidate)) goto out;
/* the allocation may have scheduled, so we need to repeat the * search lest someone else added the record whilst we were * asleep */ goto try_again; }
/* if we get here, then the user record still hadn't appeared on the * second pass - so we use the candidate record */ refcount_set(&candidate->usage, 1); atomic_set(&candidate->nkeys, 0); atomic_set(&candidate->nikeys, 0); candidate->uid = uid; candidate->qnkeys = 0; candidate->qnbytes = 0; spin_lock_init(&candidate->lock); mutex_init(&candidate->cons_lock);
rb_link_node(&candidate->node, parent, p); rb_insert_color(&candidate->node, &key_user_tree); spin_unlock(&key_user_lock); user = candidate; goto out;
/* okay - we found a user record for this UID */found: refcount_inc(&user->usage); spin_unlock(&key_user_lock); kfree(candidate);out: return user;}
/* * Dispose of a user structure */void key_user_put(struct key_user *user){ if (refcount_dec_and_lock(&user->usage, &key_user_lock)) { rb_erase(&user->node, &key_user_tree); spin_unlock(&key_user_lock);
kfree(user); }}
/* * Allocate a serial number for a key. These are assigned randomly to avoid * security issues through covert channel problems. */static inline void key_alloc_serial(struct key *key){ struct rb_node *parent, **p; struct key *xkey;
/* propose a random serial number and look for a hole for it in the * serial number tree */ do { get_random_bytes(&key->serial, sizeof(key->serial));
key->serial >>= 1; /* negative numbers are not permitted */ } while (key->serial < 3);
spin_lock(&key_serial_lock);
attempt_insertion: parent = NULL; p = &key_serial_tree.rb_node;
while (*p) { parent = *p; xkey = rb_entry(parent, struct key, serial_node);
if (key->serial < xkey->serial) p = &(*p)->rb_left; else if (key->serial > xkey->serial) p = &(*p)->rb_right; else goto serial_exists; }
/* we've found a suitable hole - arrange for this key to occupy it */ rb_link_node(&key->serial_node, parent, p); rb_insert_color(&key->serial_node, &key_serial_tree);
spin_unlock(&key_serial_lock); return;
/* we found a key with the proposed serial number - walk the tree from * that point looking for the next unused serial number */serial_exists: for (;;) { key->serial++; if (key->serial < 3) { key->serial = 3; goto attempt_insertion; }
parent = rb_next(parent); if (!parent) goto attempt_insertion;
xkey = rb_entry(parent, struct key, serial_node); if (key->serial < xkey->serial) goto attempt_insertion; }}
/** * key_alloc - Allocate a key of the specified type. * @type: The type of key to allocate. * @desc: The key description to allow the key to be searched out. * @uid: The owner of the new key. * @gid: The group ID for the new key's group permissions. * @cred: The credentials specifying UID namespace. * @perm: The permissions mask of the new key. * @flags: Flags specifying quota properties. * @restrict_link: Optional link restriction for new keyrings. * * Allocate a key of the specified type with the attributes given. The key is * returned in an uninstantiated state and the caller needs to instantiate the * key before returning. * * The restrict_link structure (if not NULL) will be freed when the * keyring is destroyed, so it must be dynamically allocated. * * The user's key count quota is updated to reflect the creation of the key and * the user's key data quota has the default for the key type reserved. The * instantiation function should amend this as necessary. If insufficient * quota is available, -EDQUOT will be returned. * * The LSM security modules can prevent a key being created, in which case * -EACCES will be returned. * * Returns a pointer to the new key if successful and an error code otherwise. * * Note that the caller needs to ensure the key type isn't uninstantiated. * Internally this can be done by locking key_types_sem. Externally, this can * be done by either never unregistering the key type, or making sure * key_alloc() calls don't race with module unloading. */struct key *key_alloc(struct key_type *type, const char *desc, kuid_t uid, kgid_t gid, const struct cred *cred, key_perm_t perm, unsigned long flags, struct key_restriction *restrict_link){ struct key_user *user = NULL; struct key *key; size_t desclen, quotalen; int ret; unsigned long irqflags;
key = ERR_PTR(-EINVAL); if (!desc || !*desc) goto error;
if (type->vet_description) { ret = type->vet_description(desc); if (ret < 0) { key = ERR_PTR(ret); goto error; } }
desclen = strlen(desc); quotalen = desclen + 1 + type->def_datalen;
/* get hold of the key tracking for this user */ user = key_user_lookup(uid); if (!user) goto no_memory_1;
/* check that the user's quota permits allocation of another key and * its description */ if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? key_quota_root_maxkeys : key_quota_maxkeys; unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? key_quota_root_maxbytes : key_quota_maxbytes;
spin_lock_irqsave(&user->lock, irqflags); 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_irqrestore(&user->lock, irqflags); }
/* allocate and initialise the key and its description */ key = kmem_cache_zalloc(key_jar, GFP_KERNEL); if (!key) goto no_memory_2;
key->index_key.desc_len = desclen; key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL); if (!key->index_key.description) goto no_memory_3; key->index_key.type = type; key_set_index_key(&key->index_key);
refcount_set(&key->usage, 1); init_rwsem(&key->sem); lockdep_set_class(&key->sem, &type->lock_class); key->user = user; key->quotalen = quotalen; key->datalen = type->def_datalen; key->uid = uid; key->gid = gid; key->perm = perm; key->expiry = TIME64_MAX; key->restrict_link = restrict_link; key->last_used_at = ktime_get_real_seconds();
key->flags |= 1 << KEY_FLAG_USER_ALIVE; if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) key->flags |= 1 << KEY_FLAG_IN_QUOTA; if (flags & KEY_ALLOC_BUILT_IN) key->flags |= 1 << KEY_FLAG_BUILTIN; if (flags & KEY_ALLOC_UID_KEYRING) key->flags |= 1 << KEY_FLAG_UID_KEYRING; if (flags & KEY_ALLOC_SET_KEEP) key->flags |= 1 << KEY_FLAG_KEEP;
#ifdef KEY_DEBUGGING key->magic = KEY_DEBUG_MAGIC;#endif
/* let the security module know about the key */ ret = security_key_alloc(key, cred, flags); if (ret < 0) goto security_error;
/* publish the key by giving it a serial number */ refcount_inc(&key->domain_tag->usage); 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_irqsave(&user->lock, irqflags); user->qnkeys--; user->qnbytes -= quotalen; spin_unlock_irqrestore(&user->lock, irqflags); } 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_irqsave(&user->lock, irqflags); user->qnkeys--; user->qnbytes -= quotalen; spin_unlock_irqrestore(&user->lock, irqflags); } key_user_put(user);no_memory_1: key = ERR_PTR(-ENOMEM); goto error;
no_quota: spin_unlock_irqrestore(&user->lock, irqflags); 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; unsigned long flags;
spin_lock_irqsave(&key->user->lock, flags);
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_irqrestore(&key->user->lock, flags); }
/* 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_set_expiry(key, prep->expiry); } }
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_set_expiry(key, ktime_get_real_seconds() + timeout);
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)) { unsigned long flags;
/* deal with the user's key tracking and quota */ if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { spin_lock_irqsave(&key->user->lock, flags); key->user->qnkeys--; key->user->qnbytes -= key->quotalen; spin_unlock_irqrestore(&key->user->lock, flags); } /* Mark key as safe for GC after key->user done. */ clear_bit_unlock(KEY_FLAG_USER_ALIVE, &key->flags); 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;}EXPORT_SYMBOL(key_lookup);
/* * 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 = TIME64_MAX;
/* make the changes with the locks held to prevent races */ down_write(&key->sem);
if (timeout > 0) expiry = ktime_get_real_seconds() + timeout; key_set_expiry(key, expiry);
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;}
/* * Create or potentially update a key. The combined logic behind * key_create_or_update() and key_create() */static 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, bool allow_update){ 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 requested and 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 (allow_update) { if (index_key.type->update) { key_ref = find_key_to_update(keyring_ref, &index_key); if (key_ref) goto found_matching_key; } } else { key_ref = find_key_to_update(keyring_ref, &index_key); if (key_ref) { key_ref_put(key_ref); key_ref = ERR_PTR(-EEXIST); goto error_link_end; } }
/* 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; }
security_key_post_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)) security_key_post_create_or_update(keyring, key, payload, plen, flags, false);
goto error_free_prep;}
/** * 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){ return __key_create_or_update(keyring_ref, type, description, payload, plen, perm, flags, true);}EXPORT_SYMBOL(key_create_or_update);
/** * key_create - 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. * * Create and instantiate a new key and link to it from the destination 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, -EEXIST if a key with the * same description already exists, -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(key_ref_t keyring_ref, const char *type, const char *description, const void *payload, size_t plen, key_perm_t perm, unsigned long flags){ return __key_create_or_update(keyring_ref, type, description, payload, plen, perm, flags, false);}EXPORT_SYMBOL(key_create);
/** * 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); 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 | SLAB_NO_MERGE, 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);}