4 files changed, 85 insertions, 1 deletions

diff --git a/lib/ldb/ldb_key_value/ldb_kv.c b/lib/ldb/ldb_key_value/ldb_kv.c
index ed0f760b5a2..aea6f0c1be0 100644
--- a/lib/ldb/ldb_key_value/ldb_kv.c
+++ b/lib/ldb/ldb_key_value/ldb_kv.c
@@ -2078,6 +2078,8 @@ static int ldb_kv_handle_request(struct ldb_module *module,
 		}
 	}
 
+	ac->timeout_timeval = tv;
+
 	/* set a spy so that we do not try to use the request context
 	 * if it is freed before ltdb_callback fires */
 	ac->spy = talloc(req, struct ldb_kv_req_spy);
diff --git a/lib/ldb/ldb_key_value/ldb_kv.h b/lib/ldb/ldb_key_value/ldb_kv.h
index f9dffae2dcf..ac474b04b4c 100644
--- a/lib/ldb/ldb_key_value/ldb_kv.h
+++ b/lib/ldb/ldb_key_value/ldb_kv.h
@@ -152,6 +152,16 @@ struct ldb_kv_context {
 	struct ldb_module *module;
 	struct ldb_request *req;
 
+	/*
+	 * Required as we might not get to the event loop before the
+	 * timeout, so we need some old-style cooperative multitasking
+	 * here.
+	 */
+	struct timeval timeout_timeval;
+
+	/* Used to throttle calls to gettimeofday() */
+	size_t timeout_counter;
+
 	bool request_terminated;
 	struct ldb_kv_req_spy *spy;
 
diff --git a/lib/ldb/ldb_key_value/ldb_kv_index.c b/lib/ldb/ldb_key_value/ldb_kv_index.c
index 1cc042aa84f..d70e5f619ef 100644
--- a/lib/ldb/ldb_key_value/ldb_kv_index.c
+++ b/lib/ldb/ldb_key_value/ldb_kv_index.c
@@ -2352,6 +2352,47 @@ static int ldb_kv_index_filter(struct ldb_kv_private *ldb_kv,
 	for (i = 0; i < num_keys; i++) {
 		int ret;
 		bool matched;
+
+		/*
+		 * Check the time every 64 records, to reduce calls to
+		 * gettimeofday().  This is a compromise, not all
+		 * calls to ldb_match_message() will take the same
+		 * time, most will run quickly but by luck it might be
+		 * possible to have 64 records that are slow, doing a
+		 * recursive search via LDAP_MATCHING_RULE_IN_CHAIN.
+		 *
+		 * Thankfully this is after index processing so only
+		 * on the subset that matches some index (but still
+		 * possibly a big one like objectclass=user)
+		 */
+		if (i % 64 == 0) {
+			struct timeval now = tevent_timeval_current();
+			int timeval_cmp = tevent_timeval_compare(&ac->timeout_timeval,
+								 &now);
+
+			/*
+			 * The search has taken too long.  This is the
+			 * most likely place for our time to expire,
+			 * as we are checking the records after the
+			 * index set intersection.  This is now the
+			 * slow process of checking if the records
+			 * actually match.
+			 *
+			 * The tevent based timeout is not likely to
+			 * be hit, sadly, as we don't run an event
+			 * loop.
+			 *
+			 * While we are indexed and most of the work
+			 * should have been done already, the
+			 * ldb_match_* calls can be quite expensive if
+			 * the caller uses LDAP_MATCHING_RULE_IN_CHAIN
+			 */
+			if (timeval_cmp <= 0) {
+				talloc_free(keys);
+				return LDB_ERR_TIME_LIMIT_EXCEEDED;
+			}
+		}
+
 		msg = ldb_msg_new(ac);
 		if (!msg) {
 			talloc_free(keys);
diff --git a/lib/ldb/ldb_key_value/ldb_kv_search.c b/lib/ldb/ldb_key_value/ldb_kv_search.c
index a0e1762bc90..46031b99c16 100644
--- a/lib/ldb/ldb_key_value/ldb_kv_search.c
+++ b/lib/ldb/ldb_key_value/ldb_kv_search.c
@@ -314,7 +314,8 @@ static int search_func(_UNUSED_ struct ldb_kv_private *ldb_kv,
 	struct ldb_context *ldb;
 	struct ldb_kv_context *ac;
 	struct ldb_message *msg, *filtered_msg;
-	int ret;
+	struct timeval now;
+	int ret, timeval_cmp;
 	bool matched;
 
 	ac = talloc_get_type(state, struct ldb_kv_context);
@@ -341,6 +342,36 @@ static int search_func(_UNUSED_ struct ldb_kv_private *ldb_kv,
 		return 0;
 	}
 
+	/*
+	 * Check the time every 64 records, to reduce calls to
+	 * gettimeofday().  This is a compromise, not all calls to
+	 * ldb_match_message() will take the same time, most will fail
+	 * quickly but by luck it might be possible to have 64 records
+	 * that are slow, doing a recursive search via
+	 * LDAP_MATCHING_RULE_IN_CHAIN.
+	 */
+	if (ac->timeout_counter++ % 64 == 0) {
+		now = tevent_timeval_current();
+		timeval_cmp = tevent_timeval_compare(&ac->timeout_timeval,
+						     &now);
+
+		/*
+		 * The search has taken too long.  This is the most
+		 * likely place for our time to expire, as we are in
+		 * an un-indexed search and we return the data from
+		 * within this loop.  The tevent based timeout is not
+		 * likely to be hit, sadly.
+		 *
+		 * ldb_match_msg_error() can be quite expensive if a
+		 * LDAP_MATCHING_RULE_IN_CHAIN extended match was
+		 * specified.
+		 */
+		if (timeval_cmp <= 0) {
+			ac->error = LDB_ERR_TIME_LIMIT_EXCEEDED;
+			return -1;
+		}
+	}
+
 	msg = ldb_msg_new(ac);
 	if (!msg) {
 		ac->error = LDB_ERR_OPERATIONS_ERROR;