[FFmpeg-cvslog] avcodec/pafvideo: Check packet size and frame code before ff_reget_buffer()

[Michael Niedermayer]

ffmpeg | branch: release/3.3 | Michael Niedermayer <michael at niedermayer.cc> | Sun Jun  4 13:38:02 2017 +0200| [b7904b58afdd12bf0dac41ee6c77f895c3af05bc] | committer: Michael Niedermayer

avcodec/pafvideo: Check packet size and frame code before ff_reget_buffer()

Fixes 1745/clusterfuzz-testcase-minimized-6160693365571584
Fixes: Timeout

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 faa5a2181df53b5226f998a20b735798addcd365)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b7904b58afdd12bf0dac41ee6c77f895c3af05bc
---

 libavcodec/pafvideo.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/libavcodec/pafvideo.c b/libavcodec/pafvideo.c
index cab3129f8f..1618a3e7c3 100644
--- a/libavcodec/pafvideo.c
+++ b/libavcodec/pafvideo.c
@@ -267,12 +267,20 @@ static int paf_video_decode(AVCodecContext *avctx, void *data,
     uint8_t code, *dst, *end;
     int i, frame, ret;
 
-    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
-        return ret;
+    if (pkt->size < 2)
+        return AVERROR_INVALIDDATA;
 
     bytestream2_init(&c->gb, pkt->data, pkt->size);
 
     code = bytestream2_get_byte(&c->gb);
+    if ((code & 0xF) > 4) {
+        avpriv_request_sample(avctx, "unknown/invalid code");
+        return AVERROR_INVALIDDATA;
+    }
+
+    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
+        return ret;
+
     if (code & 0x20) {  // frame is keyframe
         for (i = 0; i < 4; i++)
             memset(c->frame[i], 0, c->frame_size);
@@ -367,8 +375,7 @@ static int paf_video_decode(AVCodecContext *avctx, void *data,
         }
         break;
     default:
-        avpriv_request_sample(avctx, "unknown/invalid code");
-        return AVERROR_INVALIDDATA;
+        av_assert0(0);
     }
 
     av_image_copy_plane(c->pic->data[0], c->pic->linesize[0],