From patchwork Thu Feb 21 19:34:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Niedermayer X-Patchwork-Id: 12133 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 B1BDB448AF2 for ; Thu, 21 Feb 2019 21:36:05 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 95D1168AD71; Thu, 21 Feb 2019 21:36:05 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from vie01a-dmta-pe05-3.mx.upcmail.net (vie01a-dmta-pe05-3.mx.upcmail.net [84.116.36.13]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 9854368ACA6 for ; Thu, 21 Feb 2019 21:35:59 +0200 (EET) Received: from [172.31.216.235] (helo=vie01a-pemc-psmtp-pe12.mail.upcmail.net) by vie01a-dmta-pe05.mx.upcmail.net with esmtp (Exim 4.88) (envelope-from ) id 1gwu8V-0008RW-1t for ffmpeg-devel@ffmpeg.org; Thu, 21 Feb 2019 20:35:59 +0100 Received: from localhost ([213.47.41.20]) by vie01a-pemc-psmtp-pe12.mail.upcmail.net with ESMTP id wu7XgVaZY2WSswu7Xg92z6; Thu, 21 Feb 2019 20:34:59 +0100 X-Env-Mailfrom: michael@niedermayer.cc X-Env-Rcptto: ffmpeg-devel@ffmpeg.org X-SourceIP: 213.47.41.20 X-CNFS-Analysis: v=2.3 cv=E7kcWpVl c=1 sm=1 tr=0 a=I1eytVlZLDX1BM2VTtTtSw==:117 a=I1eytVlZLDX1BM2VTtTtSw==:17 a=MKtGQD3n3ToA:10 a=1oJP67jkp3AA:10 a=GEAsPZ9sns4A:10 a=ZZnuYtJkoWoA:10 a=nZOtpAppAAAA:20 a=arMOV83TbIz1EhYxCRMA:9 a=1fhp2MxaeJtTNGEnv6mo:22 a=pHzHmUro8NiASowvMSCR:22 a=nt3jZW36AmriUCFCBwmW:22 From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Thu, 21 Feb 2019 20:34:29 +0100 Message-Id: <20190221193429.19600-2-michael@niedermayer.cc> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190221193429.19600-1-michael@niedermayer.cc> References: <20190221193429.19600-1-michael@niedermayer.cc> MIME-Version: 1.0 X-CMAE-Envelope: MS4wfPAJu+JVeOsMe3S+bPSruyEnoiJ6xB+LR3VUVFeQ1o00yrz8qyTkmPyuz9QjFA3ZLj6DJlWlYpDjLMB3xZ/eYVqLwvQS8Ema9NuzLPBxxuCBrMP14m6A vHOgFqu4xr84zewdCOHoLqEdkdbQZ2mD4jw9k17ofUbBrzUYU0uqFpAG Subject: [FFmpeg-devel] [PATCH 2/2] avcodec/pnm: Avoid structure pointer dereferences in inner loop in pnm_get() 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" Improves speed from 5.4 to 4.2 seconds Fixes: 13149/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PGM_fuzzer-5760833622114304 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/pnm.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/libavcodec/pnm.c b/libavcodec/pnm.c index b06a6e81b5..17926f256f 100644 --- a/libavcodec/pnm.c +++ b/libavcodec/pnm.c @@ -36,13 +36,15 @@ static void pnm_get(PNMContext *sc, char *str, int buf_size) { char *s; int c; + uint8_t *bs = sc->bytestream; + const uint8_t *end = sc->bytestream_end; /* skip spaces and comments */ - while (sc->bytestream < sc->bytestream_end) { - c = *sc->bytestream++; + while (bs < end) { + c = *bs++; if (c == '#') { - while (c != '\n' && sc->bytestream < sc->bytestream_end) { - c = *sc->bytestream++; + while (c != '\n' && bs < end) { + c = *bs++; } } else if (!pnm_space(c)) { break; @@ -50,12 +52,13 @@ static void pnm_get(PNMContext *sc, char *str, int buf_size) } s = str; - while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) { + while (bs < end && !pnm_space(c)) { if ((s - str) < buf_size - 1) *s++ = c; - c = *sc->bytestream++; + c = *bs++; } *s = '\0'; + sc->bytestream = bs; } int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s)