diff options
| -rw-r--r-- | include/linux/key.h | 5 | ||||
| -rw-r--r-- | security/keys/gc.c | 73 |
2 files changed, 48 insertions, 30 deletions
diff --git a/include/linux/key.h b/include/linux/key.h index 96933b1e5d24..c505f83c9691 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -124,7 +124,10 @@ static inline unsigned long is_key_possessed(const key_ref_t key_ref) struct key { atomic_t usage; /* number of references */ key_serial_t serial; /* key serial number */ - struct rb_node serial_node; + union { + struct list_head graveyard_link; + struct rb_node serial_node; + }; struct key_type *type; /* type of key */ struct rw_semaphore sem; /* change vs change sem */ struct key_user *user; /* owner of this key */ diff --git a/security/keys/gc.c b/security/keys/gc.c index a42b45531aac..27610bf72195 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -168,38 +168,45 @@ do_gc: } /* - * Garbage collect an unreferenced, detached key + * Garbage collect a list of unreferenced, detached keys */ -static noinline void key_gc_unused_key(struct key *key) +static noinline void key_gc_unused_keys(struct list_head *keys) { - key_check(key); - - security_key_free(key); - - /* deal with the user's key tracking and quota */ - if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { - spin_lock(&key->user->lock); - key->user->qnkeys--; - key->user->qnbytes -= key->quotalen; - spin_unlock(&key->user->lock); - } + while (!list_empty(keys)) { + struct key *key = + list_entry(keys->next, struct key, graveyard_link); + list_del(&key->graveyard_link); + + kdebug("- %u", key->serial); + key_check(key); + + security_key_free(key); + + /* deal with the user's key tracking and quota */ + if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { + spin_lock(&key->user->lock); + key->user->qnkeys--; + key->user->qnbytes -= key->quotalen; + spin_unlock(&key->user->lock); + } - atomic_dec(&key->user->nkeys); - if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) - atomic_dec(&key->user->nikeys); + atomic_dec(&key->user->nkeys); + if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) + atomic_dec(&key->user->nikeys); - key_user_put(key->user); + key_user_put(key->user); - /* now throw away the key memory */ - if (key->type->destroy) - key->type->destroy(key); + /* now throw away the key memory */ + if (key->type->destroy) + key->type->destroy(key); - kfree(key->description); + kfree(key->description); #ifdef KEY_DEBUGGING - key->magic = KEY_DEBUG_MAGIC_X; + key->magic = KEY_DEBUG_MAGIC_X; #endif - kmem_cache_free(key_jar, key); + kmem_cache_free(key_jar, key); + } } /* @@ -211,6 +218,7 @@ static noinline void key_gc_unused_key(struct key *key) */ static void key_garbage_collector(struct work_struct *work) { + static LIST_HEAD(graveyard); static u8 gc_state; /* Internal persistent state */ #define KEY_GC_REAP_AGAIN 0x01 /* - Need another cycle */ #define KEY_GC_REAPING_LINKS 0x02 /* - We need to reap links */ @@ -316,15 +324,22 @@ maybe_resched: key_schedule_gc(new_timer); } - if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2)) { - /* Make sure everyone revalidates their keys if we marked a - * bunch as being dead and make sure all keyring ex-payloads - * are destroyed. + if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2) || + !list_empty(&graveyard)) { + /* Make sure that all pending keyring payload destructions are + * fulfilled and that people aren't now looking at dead or + * dying keys that they don't have a reference upon or a link + * to. */ - kdebug("dead sync"); + kdebug("gc sync"); synchronize_rcu(); } + if (!list_empty(&graveyard)) { + kdebug("gc keys"); + key_gc_unused_keys(&graveyard); + } + if (unlikely(gc_state & (KEY_GC_REAPING_DEAD_1 | KEY_GC_REAPING_DEAD_2))) { if (!(gc_state & KEY_GC_FOUND_DEAD_KEY)) { @@ -359,7 +374,7 @@ found_unreferenced_key: rb_erase(&key->serial_node, &key_serial_tree); spin_unlock(&key_serial_lock); - key_gc_unused_key(key); + list_add_tail(&key->graveyard_link, &graveyard); gc_state |= KEY_GC_REAP_AGAIN; goto maybe_resched; |