[FFmpeg-cvslog] avformat/smjpegdec: Check the existence of referred streams

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Mon Jul  6 20:18:42 2020 +0200| [bcbfcf1300b331874f522df43f658d66f6cdd6a7] | committer: Michael Niedermayer

avformat/smjpegdec: Check the existence of referred streams

Fixes: Assertion failure
Fixes: 23758/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5160954605338624.fuzz

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 321ea59dac6538f92206bab0a2688fa24a25c4d2)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bcbfcf1300b331874f522df43f658d66f6cdd6a7
---

 libavformat/smjpegdec.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libavformat/smjpegdec.c b/libavformat/smjpegdec.c
index 5bc04921fe..a4e1f957ed 100644
--- a/libavformat/smjpegdec.c
+++ b/libavformat/smjpegdec.c
@@ -51,6 +51,9 @@ static int smjpeg_read_header(AVFormatContext *s)
     uint32_t version, htype, hlength, duration;
     char *comment;
 
+    sc->audio_stream_index =
+    sc->video_stream_index = -1;
+
     avio_skip(pb, 8); // magic
     version = avio_rb32(pb);
     if (version)
@@ -147,6 +150,8 @@ static int smjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
     dtype = avio_rl32(s->pb);
     switch (dtype) {
     case SMJPEG_SNDD:
+        if (sc->audio_stream_index < 0)
+            return AVERROR_INVALIDDATA;
         timestamp = avio_rb32(s->pb);
         size = avio_rb32(s->pb);
         ret = av_get_packet(s->pb, pkt, size);
@@ -155,6 +160,8 @@ static int smjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
         pkt->pos = pos;
         break;
     case SMJPEG_VIDD:
+        if (sc->video_stream_index < 0)
+            return AVERROR_INVALIDDATA;
         timestamp = avio_rb32(s->pb);
         size = avio_rb32(s->pb);
         ret = av_get_packet(s->pb, pkt, size);