[FFmpeg-cvslog] avformat/ipmovie: Check signature_buffer read

[Michael Niedermayer]

ffmpeg | branch: release/7.1 | Michael Niedermayer <michael at niedermayer.cc> | Thu Dec 26 03:07:51 2024 +0100| [43eaca54bc88f86be84b3c7b276bd03a71a72653] | committer: Michael Niedermayer

avformat/ipmovie: Check signature_buffer read

Fixes: use of uninitilaized data
Fixes: 385167047/clusterfuzz-testcase-minimized-ffmpeg_dem_IPMOVIE_fuzzer-5941477505564672

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 788abe0d253b2034af15876d7889265d4746df2b)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=43eaca54bc88f86be84b3c7b276bd03a71a72653
---

 libavformat/ipmovie.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/ipmovie.c b/libavformat/ipmovie.c
index 5d1748953a..3701be276f 100644
--- a/libavformat/ipmovie.c
+++ b/libavformat/ipmovie.c
@@ -614,7 +614,8 @@ static int ipmovie_read_header(AVFormatContext *s)
 
     ipmovie->avf = s;
 
-    avio_read(pb, signature_buffer, sizeof(signature_buffer));
+    if (avio_read(pb, signature_buffer, sizeof(signature_buffer)) != sizeof(signature_buffer))
+        return AVERROR_INVALIDDATA;
     while (memcmp(signature_buffer, signature, sizeof(signature))) {
         memmove(signature_buffer, signature_buffer + 1, sizeof(signature_buffer) - 1);
         signature_buffer[sizeof(signature_buffer) - 1] = avio_r8(pb);