From 5a2a7604da5f7a2fc498d1d5c90bd892edac9ce8 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 27 Sep 2020 20:23:10 +0200 Subject: [PATCH] avcodec/cook: Check subpacket index against max Fixes: off by 1 error Fixes: index 5 out of bounds for type 'COOKSubpacket [5]' Fixes: 25772/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_COOK_fuzzer-5762459498184704.fuzz Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/cook.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/libavcodec/cook.c b/libavcodec/cook.c index d0b41a2431..9582495442 100644 --- a/libavcodec/cook.c +++ b/libavcodec/cook.c @@ -1084,6 +1084,10 @@ static av_cold int cook_decode_init(AVCodecContext *avctx) ff_audiodsp_init(&q->adsp); while (bytestream2_get_bytes_left(&gb)) { + if (s >= FFMIN(MAX_SUBPACKETS, avctx->block_align)) { + avpriv_request_sample(avctx, "subpackets > %d", FFMIN(MAX_SUBPACKETS, avctx->block_align)); + return AVERROR_PATCHWELCOME; + } /* 8 for mono, 16 for stereo, ? for multichannel Swap to right endianness so we don't need to care later on. */ q->subpacket[s].cookversion = bytestream2_get_be32(&gb); @@ -1215,10 +1219,6 @@ static av_cold int cook_decode_init(AVCodecContext *avctx) q->num_subpackets++; s++; - if (s > FFMIN(MAX_SUBPACKETS, avctx->block_align)) { - avpriv_request_sample(avctx, "subpackets > %d", FFMIN(MAX_SUBPACKETS, avctx->block_align)); - return AVERROR_PATCHWELCOME; - } } /* Try to catch some obviously faulty streams, otherwise it might be exploitable */