From patchwork Thu Oct 31 17:58:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Niedermayer X-Patchwork-Id: 16051 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 4100F449347 for ; Thu, 31 Oct 2019 20:07:45 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2BA5168B3A6; Thu, 31 Oct 2019 20:07:45 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from vie01a-dmta-pe03-2.mx.upcmail.net (vie01a-dmta-pe03-2.mx.upcmail.net [62.179.121.161]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id C807F68B384 for ; Thu, 31 Oct 2019 20:07:38 +0200 (EET) Received: from [172.31.216.235] (helo=vie01a-pemc-psmtp-pe12.mail.upcmail.net) by vie01a-dmta-pe03.mx.upcmail.net with esmtp (Exim 4.92) (envelope-from ) id 1iQEkW-0004vo-1G for ffmpeg-devel@ffmpeg.org; Thu, 31 Oct 2019 19:00:44 +0100 Received: from localhost ([213.47.68.29]) by vie01a-pemc-psmtp-pe12.mail.upcmail.net with ESMTP id QEjYikTYAwlysQEjYi87T9; Thu, 31 Oct 2019 18:59:44 +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=E5OzWpVl c=1 sm=1 tr=0 a=2hcxjKEKjp0CzLx6oWAm4g==:117 a=2hcxjKEKjp0CzLx6oWAm4g==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=MKtGQD3n3ToA:10 a=1oJP67jkp3AA:10 a=GEAsPZ9sns4A:10 a=ZZnuYtJkoWoA:10 a=nZOtpAppAAAA:20 a=Jkauj4J3AQXWOLFq8csA:9 a=1fhp2MxaeJtTNGEnv6mo:22 a=Z5ABNNGmrOfJ6cZ5bIyy:22 a=UDnyf2zBuKT2w-IlGP_r:22 From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Thu, 31 Oct 2019 18:58:29 +0100 Message-Id: <20191031175830.24895-7-michael@niedermayer.cc> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191031175830.24895-1-michael@niedermayer.cc> References: <20191031175830.24895-1-michael@niedermayer.cc> MIME-Version: 1.0 X-CMAE-Envelope: MS4wfBCZOFRl9fZHvZZ5m0CPZLKK9cvGYJVOu0Nl0FQTYjrLZcD7qPsUeYqoHlBej3Ch0ZstT8Yd2c7fiuwDnQp7Eb2HaJqSJL/v12PZ0mpPOEOG3myVAt9A v6ywVEpeKgy0KhM1k4lRAcz6ZC4xuP4SeoOIw/WZoF6b0d4Gy7WGOy/y Subject: [FFmpeg-devel] [PATCH 7/8] avcodec/vc1_block: Fix undefined behavior in ac prediction rescaling 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 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" The intermediates are required to fit in 12bit (8.1.3.9 Coefficient Scaling) See SMPTE 421M-2006 and Amendment 1-2007 Fixes: signed integer overflow: -20691 * 262144 cannot be represented in type 'int' Fixes: 18479/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5128912371187712 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index 4c6dfaf6bf..da0eee8cc7 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -1036,10 +1036,10 @@ static int vc1_decode_intra_block(VC1Context *v, int16_t block[64], int n, if (q2 && q1 != q2) { if (dc_pred_dir) { // left for (k = 1; k < 8; k++) - block[k << v->left_blk_sh] += (ac_val[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; + block[k << v->left_blk_sh] += (int)(ac_val[k] * q2 * (unsigned)ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; } else { //top for (k = 1; k < 8; k++) - block[k << v->top_blk_sh] += (ac_val[k + 8] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; + block[k << v->top_blk_sh] += (int)(ac_val[k + 8] * q2 * (unsigned)ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; } } else { if (dc_pred_dir) { // left