[FFmpeg-cvslog] avcodec/mss4: Check input size against skip bits
Michael Niedermayer
git at videolan.org
Wed Jun 5 14:21:16 EEST 2019
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue May 14 14:29:43 2019 +0200| [0fef412dffb74fef3494f7fae0c138c32a444484] | committer: Michael Niedermayer
avcodec/mss4: Check input size against skip bits
Fixes: Timeout (17sec -> 20ms)
Fixes: 14615/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MTS2_fuzzer-5093007763701760
Fixes: 14797/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MTS2_fuzzer-5651696119709696
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=0fef412dffb74fef3494f7fae0c138c32a444484
---
libavcodec/mss4.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/libavcodec/mss4.c b/libavcodec/mss4.c
index b58c21be93..76c746a2d5 100644
--- a/libavcodec/mss4.c
+++ b/libavcodec/mss4.c
@@ -552,6 +552,11 @@ static int mss4_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
"Empty frame found but it is not a skip frame.\n");
return AVERROR_INVALIDDATA;
}
+ mb_width = FFALIGN(width, 16) >> 4;
+ mb_height = FFALIGN(height, 16) >> 4;
+
+ if (frame_type != SKIP_FRAME && 8*buf_size < 8*HEADER_SIZE + mb_width*mb_height)
+ return AVERROR_INVALIDDATA;
if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
return ret;
@@ -574,9 +579,6 @@ static int mss4_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
if ((ret = init_get_bits8(&gb, buf + HEADER_SIZE, buf_size - HEADER_SIZE)) < 0)
return ret;
-
- mb_width = FFALIGN(width, 16) >> 4;
- mb_height = FFALIGN(height, 16) >> 4;
dst[0] = c->pic->data[0];
dst[1] = c->pic->data[1];
dst[2] = c->pic->data[2];
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