From 0fef412dffb74fef3494f7fae0c138c32a444484 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 14 May 2019 14:29:43 +0200 Subject: [PATCH] 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 --- 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];