From patchwork Wed Mar 17 23:17:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Niedermayer X-Patchwork-Id: 26430 Return-Path: X-Original-To: patchwork@ffaux-bg.ffmpeg.org Delivered-To: patchwork@ffaux-bg.ffmpeg.org Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by ffaux.localdomain (Postfix) with ESMTP id 4720D44A6A9 for ; Thu, 18 Mar 2021 01:23:59 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2159068924E; Thu, 18 Mar 2021 01:23:59 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from vie01a-dmta-pe01-3.mx.upcmail.net (vie01a-dmta-pe01-3.mx.upcmail.net [62.179.121.156]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id F190468814E for ; Thu, 18 Mar 2021 01:23:52 +0200 (EET) Received: from [172.31.216.235] (helo=vie01a-pemc-psmtp-pe12.mail.upcmail.net) by vie01a-dmta-pe01.mx.upcmail.net with esmtp (Exim 4.92) (envelope-from ) id 1lMfQr-0007lL-0E for ffmpeg-devel@ffmpeg.org; Thu, 18 Mar 2021 00:18:29 +0100 Received: from localhost ([213.47.68.29]) by vie01a-pemc-psmtp-pe12.mail.upcmail.net with ESMTP id MfPslhiLlljeHMfPslmq3g; Thu, 18 Mar 2021 00:17:29 +0100 X-Env-Mailfrom: michael@niedermayer.cc X-Env-Rcptto: ffmpeg-devel@ffmpeg.org X-SourceIP: 213.47.68.29 X-CNFS-Analysis: v=2.3 cv=BoHjPrf5 c=1 sm=1 tr=0 a=2hcxjKEKjp0CzLx6oWAm4g==:117 a=2hcxjKEKjp0CzLx6oWAm4g==:17 a=MKtGQD3n3ToA:10 a=1oJP67jkp3AA:10 a=GEAsPZ9sns4A:10 a=ZZnuYtJkoWoA:10 a=nZOtpAppAAAA:20 a=Qwg7M1AyrvXW4yjTEaAA:9 a=1fhp2MxaeJtTNGEnv6mo:22 a=Z5ABNNGmrOfJ6cZ5bIyy:22 a=UDnyf2zBuKT2w-IlGP_r:22 From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Thu, 18 Mar 2021 00:17:26 +0100 Message-Id: <20210317231728.2130-1-michael@niedermayer.cc> X-Mailer: git-send-email 2.17.1 X-CMAE-Envelope: MS4wfNhjD5KfqI8F5669nETco59SgH1AJ3dgXm64MyjoSEQi4mtL1jJ1DwypH06XNqPT8P986rwL6uBdgafo59e0H1TtUBhWuw9/SCJq20OXy3ErGQ6U6+NU 9Xuz0SGU/TmRTvISaR+1ODKLDgWSG4m7EZxiq47r1UJLl6Gvwhbki3nn Subject: [FFmpeg-devel] [PATCH 1/3] avformat/mpc8: check for size overflow in mpc8_get_chunk_header() X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches MIME-Version: 1.0 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Fixes: signed integer overflow: -9223372036854775760 - 50 cannot be represented in type 'long' Fixes: 31673/clusterfuzz-testcase-minimized-ffmpeg_dem_MPC8_fuzzer-580134751869337 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/mpc8.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/libavformat/mpc8.c b/libavformat/mpc8.c index ff7da2ef55..b12a417f63 100644 --- a/libavformat/mpc8.c +++ b/libavformat/mpc8.c @@ -127,7 +127,11 @@ static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size) pos = avio_tell(pb); *tag = avio_rl16(pb); *size = ffio_read_varlen(pb); - *size -= avio_tell(pb) - pos; + pos -= avio_tell(pb); + if (av_sat_add64(*size, pos) != (uint64_t)*size + pos) { + *size = -1; + } else + *size += pos; } static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)