[FFmpeg-cvslog] avformat/iff: Check that we have a stream in read_dst_frame()

[Michael Niedermayer]

ffmpeg | branch: release/7.1 | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb  9 01:28:17 2025 +0100| [d3929313917fddc8689f8faecda0966d0a4498a3] | committer: Michael Niedermayer

avformat/iff: Check that we have a stream in read_dst_frame()

Fixes: null pointer dereference
Fixes: 385644864/clusterfuzz-testcase-minimized-ffmpeg_dem_IFF_fuzzer-4551049565765632

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Peter Ross <pross at xvid.org>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 8668957ef604bd2b99175310638bc5031ae0d991)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d3929313917fddc8689f8faecda0966d0a4498a3
---

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

diff --git a/libavformat/iff.c b/libavformat/iff.c
index 7601baa629..6b4503fdb3 100644
--- a/libavformat/iff.c
+++ b/libavformat/iff.c
@@ -360,6 +360,9 @@ static int read_dst_frame(AVFormatContext *s, AVPacket *pkt)
     uint64_t chunk_pos, data_pos, data_size;
     int ret = AVERROR_EOF;
 
+    if (s->nb_streams < 1)
+        return AVERROR_INVALIDDATA;
+
     while (!avio_feof(pb)) {
         chunk_pos = avio_tell(pb);
         if (chunk_pos >= iff->body_end)