From: Kokan <kokaipeter@gmail.com>
Date: Fri, 24 Jul 2020 11:03:19 +0200
Subject: syslogformat: sd_step skip if no char left

Fixes #3328 and hopefully a few similuar not discovered crashes like that.

Signed-off-by: Kokan <kokaipeter@gmail.com>
Bug: https://github.com/syslog-ng/syslog-ng/issues/3328
Origin: https://github.com/syslog-ng/syslog-ng/commit/0ce839090986670290461c52d3a70046659e86
---
 modules/syslogformat/syslog-format.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/modules/syslogformat/syslog-format.c b/modules/syslogformat/syslog-format.c
index ec4b570..d81c74e 100644
--- a/modules/syslogformat/syslog-format.c
+++ b/modules/syslogformat/syslog-format.c
@@ -47,11 +47,16 @@ static struct
   NVHandle raw_message;
 } handles;
 
-static inline void
+static inline gboolean
 sd_step(const guchar **data, gint *left)
 {
+  if (*left < 1)
+    return FALSE;
+
   (*data)++;
   (*left)--;
+
+  return TRUE;
 }