[FFmpeg-cvslog] avformat/iff: check size against INT64_MAX

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Oct 27 21:51:08 2020 +0100| [f291cd681b1235e150464ad83974d60d6879b492] | committer: Michael Niedermayer

avformat/iff: check size against INT64_MAX

Bigger sizes are misinterpreted as negative numbers by the API
Fixes: infinite loop
Fixes: 26611/clusterfuzz-testcase-minimized-ffmpeg_dem_IFF_fuzzer-4890614975692800

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f291cd681b1235e150464ad83974d60d6879b492
---

 libavformat/iff.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavformat/iff.c b/libavformat/iff.c
index fb76aed4c3..a70184f105 100644
--- a/libavformat/iff.c
+++ b/libavformat/iff.c
@@ -223,6 +223,9 @@ static int parse_dsd_diin(AVFormatContext *s, AVStream *st, uint64_t eof)
         uint64_t orig_pos = avio_tell(pb);
         const char * metadata_tag = NULL;
 
+        if (size >= INT64_MAX)
+            return AVERROR_INVALIDDATA;
+
         switch(tag) {
         case MKTAG('D','I','A','R'): metadata_tag = "artist"; break;
         case MKTAG('D','I','T','I'): metadata_tag = "title";  break;