[FFmpeg-cvslog] avcodec/qpeg: Limit copy in qpeg_decode_intra() to the available bytes

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb 24 00:44:40 2019 +0100| [36a1939b59f0a966cda4de8215621db626833694] | committer: Michael Niedermayer

avcodec/qpeg: Limit copy in qpeg_decode_intra() to the available bytes

Fixes: Timeout (27 sec -> 39 milli sec)
Fixes: 13151/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_QPEG_fuzzer-5717536023248896

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 b819472995f55e827d6bb70dcdd86d963f65ae31)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=36a1939b59f0a966cda4de8215621db626833694
---

 libavcodec/qpeg.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/qpeg.c b/libavcodec/qpeg.c
index e1210c1972..10b55d2dff 100644
--- a/libavcodec/qpeg.c
+++ b/libavcodec/qpeg.c
@@ -90,6 +90,8 @@ static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
                 }
             }
         } else {
+            if (bytestream2_get_bytes_left(&qctx->buffer) < copy)
+                copy = bytestream2_get_bytes_left(&qctx->buffer);
             for(i = 0; i < copy; i++) {
                 dst[filled++] = bytestream2_get_byte(&qctx->buffer);
                 if (filled >= width) {