[FFmpeg-cvslog] avdevice/xcbgrab: Check sscanf() return

[Michael Niedermayer]

ffmpeg | branch: release/5.1 | Michael Niedermayer <michael at niedermayer.cc> | Sun Jun  2 23:32:43 2024 +0200| [4446e6b55fe4b47f1a4b9ff26b63eb6fe0ff03ab] | committer: Michael Niedermayer

avdevice/xcbgrab: Check sscanf() return

Alot more input checking can be performed, this is only checking the obvious missing case

Fixes: CID1598562 Unchecked return value

Sponsored-by: Sovereign Tech Fund
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 78d6d13babc62fa14727ee590e5a9661f23a0d9f)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4446e6b55fe4b47f1a4b9ff26b63eb6fe0ff03ab
---

 libavdevice/xcbgrab.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libavdevice/xcbgrab.c b/libavdevice/xcbgrab.c
index 64a68ba497..e76af06331 100644
--- a/libavdevice/xcbgrab.c
+++ b/libavdevice/xcbgrab.c
@@ -826,7 +826,10 @@ static av_cold int xcbgrab_read_header(AVFormatContext *s)
 
     if (!sscanf(s->url, "%[^+]+%d,%d", display_name, &c->x, &c->y)) {
         *display_name = 0;
-        sscanf(s->url, "+%d,%d", &c->x, &c->y);
+        if(sscanf(s->url, "+%d,%d", &c->x, &c->y) != 2) {
+            if (*s->url)
+                av_log(s, AV_LOG_WARNING, "Ambigous URL: %s\n", s->url);
+        }
     }
 
     c->conn = xcb_connect(display_name[0] ? display_name : NULL, &screen_num);