1 files changed, 37 insertions, 0 deletions

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index b4b3677657d6..f289982cb5db 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -22,6 +22,31 @@
 
 #define key_negative_timeout	60	/* default timeout on a negative key's existence */
 
+static struct key *check_cached_key(struct keyring_search_context *ctx)
+{
+#ifdef CONFIG_KEYS_REQUEST_CACHE
+	struct key *key = current->cached_requested_key;
+
+	if (key &&
+	    ctx->match_data.cmp(key, &ctx->match_data) &&
+	    !(key->flags & ((1 << KEY_FLAG_INVALIDATED) |
+			    (1 << KEY_FLAG_REVOKED))))
+		return key_get(key);
+#endif
+	return NULL;
+}
+
+static void cache_requested_key(struct key *key)
+{
+#ifdef CONFIG_KEYS_REQUEST_CACHE
+	struct task_struct *t = current;
+
+	key_put(t->cached_requested_key);
+	t->cached_requested_key = key_get(key);
+	set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
+#endif
+}
+
 /**
  * complete_request_key - Complete the construction of a key.
  * @authkey: The authorisation key.
@@ -562,6 +587,10 @@ struct key *request_key_and_link(struct key_type *type,
 		}
 	}
 
+	key = check_cached_key(&ctx);
+	if (key)
+		return key;
+
 	/* search all the process keyrings for a key */
 	rcu_read_lock();
 	key_ref = search_process_keyrings_rcu(&ctx);
@@ -587,6 +616,9 @@ struct key *request_key_and_link(struct key_type *type,
 				goto error_free;
 			}
 		}
+
+		/* Only cache the key on immediate success */
+		cache_requested_key(key);
 	} else if (PTR_ERR(key_ref) != -EAGAIN) {
 		key = ERR_CAST(key_ref);
 	} else  {
@@ -786,6 +818,10 @@ struct key *request_key_rcu(struct key_type *type, const char *description)
 
 	kenter("%s,%s", type->name, description);
 
+	key = check_cached_key(&ctx);
+	if (key)
+		return key;
+
 	/* search all the process keyrings for a key */
 	key_ref = search_process_keyrings_rcu(&ctx);
 	if (IS_ERR(key_ref)) {
@@ -794,6 +830,7 @@ struct key *request_key_rcu(struct key_type *type, const char *description)
 			key = ERR_PTR(-ENOKEY);
 	} else {
 		key = key_ref_to_ptr(key_ref);
+		cache_requested_key(key);
 	}
 
 	kleave(" = %p", key);