[FFmpeg-cvslog] avcodec/parser: Check next index validity in ff_combine_frame()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Jul  6 09:21:52 2019 +0200| [15008db0fac6d97bb939fa7ef9e92d79bf1f7cb1] | committer: Michael Niedermayer

avcodec/parser: Check next index validity in ff_combine_frame()

Fixes: out of array access
Fixes: 15522/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DNXHD_fuzzer-5747756078989312

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=15008db0fac6d97bb939fa7ef9e92d79bf1f7cb1
---

 libavcodec/parser.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/parser.c b/libavcodec/parser.c
index 0a994a3f30..3e19810a94 100644
--- a/libavcodec/parser.c
+++ b/libavcodec/parser.c
@@ -245,6 +245,9 @@ int ff_combine_frame(ParseContext *pc, int next,
     for (; pc->overread > 0; pc->overread--)
         pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];
 
+    if (next > *buf_size)
+        return AVERROR(EINVAL);
+
     /* flush remaining if EOF */
     if (!*buf_size && next == END_NOT_FOUND)
         next = 0;