systemd/0001-If-the-notification-message-length-is-0-ignore-the-m.patch

From ddcd0b726adfd78260ec3d6a446800d85980069e Mon Sep 17 00:00:00 2001
From: Jorge Niedbalski <jorge.niedbalski@canonical.com>
Date: Wed, 28 Sep 2016 18:25:50 -0300
Subject: [PATCH 1/1] If the notification message length is 0, ignore the
 message (#4237)

Fixes #4234.

Signed-off-by: Jorge Niedbalski <jnr@metaklass.org>
(cherry picked from commit 531ac2b2349da02acc9c382849758e07eb92b020)
---
 src/core/manager.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/core/manager.c b/src/core/manager.c
index 229cb31..56ca9cf 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -1565,6 +1565,10 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t
 
                 return -errno;
         }
+        if (n == 0) {
+                log_debug("Got zero-length notification message. Ignoring.");
+                return 0;
+        }
 
         CMSG_FOREACH(cmsg, &msghdr) {
                 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
-- 
2.10.0