From: Martin Schwenke <martin@meltin.net>
Date: Fri, 21 Jan 2022 01:14:05 +0000 (+1100)
Subject: ctdb-locking: Don't pass NULL to tevent_req_is_unix_error()
X-Git-Tag: talloc-2.3.4~279
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d52b497d11a2d5d82fabc8d20d656682af2f3c9d;p=thirdparty%2Fsamba.git

ctdb-locking: Don't pass NULL to tevent_req_is_unix_error()

If there is an error then this pointer is unconditionally
dereferenced.

However, the only possible error appears to be ENOMEM, where a crash
caused by dereferencing a NULL pointer isn't a terrible outcome.  In
the absence of a security issue this is probably not worth
backporting.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>
---

diff --git a/ctdb/server/ctdb_lock_helper.c b/ctdb/server/ctdb_lock_helper.c
index 6b6fbbe27a5..51d2992b64e 100644
--- a/ctdb/server/ctdb_lock_helper.c
+++ b/ctdb/server/ctdb_lock_helper.c
@@ -230,9 +230,9 @@ static void wait_for_parent_check(struct tevent_req *subreq)
 	tevent_req_set_callback(subreq, wait_for_parent_check, req);
 }
 
-static bool wait_for_parent_recv(struct tevent_req *req)
+static bool wait_for_parent_recv(struct tevent_req *req, int *perr)
 {
-	if (tevent_req_is_unix_error(req, NULL)) {
+	if (tevent_req_is_unix_error(req, perr)) {
 		return false;
 	}
 
@@ -273,6 +273,7 @@ int main(int argc, char *argv[])
 	int ppid;
 	const char *lock_type;
 	bool status;
+	int err;
 
 	reset_scheduler();
 
@@ -336,9 +337,11 @@ int main(int argc, char *argv[])
 
 	tevent_req_poll(req, ev);
 
-	status = wait_for_parent_recv(req);
+	status = wait_for_parent_recv(req, &err);
 	if (! status) {
-		fprintf(stderr, "locking: wait_for_parent_recv() failed\n");
+		fprintf(stderr,
+			"locking: wait_for_parent_recv() failed (%d)\n",
+			err);
 	}
 
 	talloc_free(ev);