[FFmpeg-cvslog] avformat/nuv: return early if header id fails to read

[Kacper Michajłow]

ffmpeg | branch: master | Kacper Michajłow <kasper93 at gmail.com> | Tue Jun 25 23:50:30 2024 +0200| [02b3fc582693477555ce151515972bfee04367a9] | committer: Michael Niedermayer

avformat/nuv: return early if header id fails to read

Fixes use of uninitialized value in memcmp below, reported by MSAN.

Found by OSS-Fuzz.

Signed-off-by: Kacper Michajłow <kasper93 at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=02b3fc582693477555ce151515972bfee04367a9
---

 libavformat/nuv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavformat/nuv.c b/libavformat/nuv.c
index 507a73b0fe..49915ecf16 100644
--- a/libavformat/nuv.c
+++ b/libavformat/nuv.c
@@ -165,7 +165,9 @@ static int nuv_header(AVFormatContext *s)
     int is_mythtv, width, height, v_packs, a_packs, ret;
     AVStream *vst = NULL, *ast = NULL;
 
-    avio_read(pb, id_string, 12);
+    if ((ret = ffio_read_size(pb, id_string, 12)) < 0)
+        return ret;
+
     is_mythtv = !memcmp(id_string, "MythTVVideo", 12);
     avio_skip(pb, 5);       // version string
     avio_skip(pb, 3);       // padding