From 592a76c1c096dad29322688b5da8763a680b96d8 Mon Sep 17 00:00:00 2001
From: Sven Steudte <sven.steudte@gmail.com>
Date: Mon, 20 Sep 2021 19:13:11 +0200
Subject: [PATCH] Added exception for corrupt marker data

---
 ssdv.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/ssdv.c b/ssdv.c
index c05b4ec..c6f8b84 100644
--- a/ssdv.c
+++ b/ssdv.c
@@ -721,7 +721,7 @@ static char ssdv_have_marker(ssdv_t *s)
 static char ssdv_have_marker_data(ssdv_t *s)
 {
 	uint8_t *d = s->marker_data;
-	size_t l = s->marker_len;
+	ssize_t l = s->marker_len;
 	int i;
 	
 	switch(s->marker)
@@ -879,6 +879,11 @@ static char ssdv_have_marker_data(ssdv_t *s)
 				j += d[i];
 			
 			l -= j;
+			if (l < 0)
+			{
+				fprintf(stderr, "The image has an invalid marker length\n");
+				return(SSDV_ERROR);
+			}
 			d += j;
 		}
 		break;
@@ -895,6 +900,11 @@ static char ssdv_have_marker_data(ssdv_t *s)
 			
 			/* Skip to the next one, if present */
 			l -= 65;
+			if (l < 0)
+			{
+				fprintf(stderr, "The image has an invalid marker length\n");
+				return(SSDV_ERROR);
+			}
 			d += 65;
 		}
 		break;