[FFmpeg-cvslog] avformat/apetag: Check APETAGEX

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Mon Aug 19 17:02:12 2024 +0200| [890212e83d464250dcd612bfabd8f86c85bd2dfa] | committer: Michael Niedermayer

avformat/apetag: Check APETAGEX

Fixes: Use of uninitialized value
Fixes: 71074/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-5697034877730816

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 796ff2d599449ed798b69ab798ebcbcc0a5853f5)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=890212e83d464250dcd612bfabd8f86c85bd2dfa
---

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

diff --git a/libavformat/apetag.c b/libavformat/apetag.c
index 2ee277f864..38ab5c4089 100644
--- a/libavformat/apetag.c
+++ b/libavformat/apetag.c
@@ -129,7 +129,8 @@ int64_t ff_ape_parse_tag(AVFormatContext *s)
 
     avio_seek(pb, file_size - APE_TAG_FOOTER_BYTES, SEEK_SET);
 
-    avio_read(pb, buf, 8);     /* APETAGEX */
+    if(avio_read(pb, buf, 8) != 8)     /* APETAGEX */
+        return 0;
     if (strncmp(buf, APE_TAG_PREAMBLE, 8)) {
         return 0;
     }