From eed8561f7cb845aa6df8daf4abf1945be18a4930 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 17 May 2019 23:28:49 +0200 Subject: [PATCH] avcodec/vmnc: Check available space against chunks before reget_buffer() Fixes: Timeout (16sec -> 60ms) Fixes: 14673/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VMNC_fuzzer-5640217517621248 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 279d9a84af37cc1a7cf79c1cd667105eeb948611) Signed-off-by: Michael Niedermayer --- libavcodec/vmnc.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/libavcodec/vmnc.c b/libavcodec/vmnc.c index 30b1414e49..e273043311 100644 --- a/libavcodec/vmnc.c +++ b/libavcodec/vmnc.c @@ -333,11 +333,15 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, uint8_t *outptr; int dx, dy, w, h, depth, enc, chunks, res, size_left, ret; + bytestream2_init(gb, buf, buf_size); + bytestream2_skip(gb, 2); + chunks = bytestream2_get_be16(gb); + if (12LL * chunks > bytestream2_get_bytes_left(gb)) + return AVERROR_INVALIDDATA; + if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) return ret; - bytestream2_init(gb, buf, buf_size); - c->pic->key_frame = 0; c->pic->pict_type = AV_PICTURE_TYPE_P; @@ -369,8 +373,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, } } } - bytestream2_skip(gb, 2); - chunks = bytestream2_get_be16(gb); + while (chunks--) { if (bytestream2_get_bytes_left(gb) < 12) { av_log(avctx, AV_LOG_ERROR, "Premature end of data!\n");