From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 07ED8404BA for ; Wed, 21 Dec 2022 23:05:32 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 4607F68BA02; Thu, 22 Dec 2022 01:05:29 +0200 (EET) Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [217.70.183.199]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 31F5568B0DB for ; Thu, 22 Dec 2022 01:05:21 +0200 (EET) Received: (Authenticated sender: michael@niedermayer.cc) by mail.gandi.net (Postfix) with ESMTPSA id CC6CCFF80C for ; Wed, 21 Dec 2022 23:05:20 +0000 (UTC) From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Thu, 22 Dec 2022 00:05:20 +0100 Message-Id: <20221221230520.11540-1-michael@niedermayer.cc> X-Mailer: git-send-email 2.17.1 Subject: [FFmpeg-devel] [PATCH] avcodec/sunrast: Fix maplength check X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 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 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Fixes: out of bounds read Found-by: Ibrahim Mohamed Reviewed-by; Ibrahim Mohamed Signed-off-by: Michael Niedermayer --- libavcodec/sunrast.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/libavcodec/sunrast.c b/libavcodec/sunrast.c index 45b29e4d72..3668d2be7f 100644 --- a/libavcodec/sunrast.c +++ b/libavcodec/sunrast.c @@ -19,6 +19,7 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#include "libavutil/avassert.h" #include "libavutil/common.h" #include "libavutil/intreadwrite.h" #include "avcodec.h" @@ -75,6 +76,12 @@ static int sunrast_decode_frame(AVCodecContext *avctx, AVFrame *p, return AVERROR_PATCHWELCOME; } + if (maplength > 768) { + av_log(avctx, AV_LOG_WARNING, "invalid colormap length\n"); + return AVERROR_INVALIDDATA; + } + + // This also checks depth to be valid switch (depth) { case 1: avctx->pix_fmt = maplength ? AV_PIX_FMT_PAL8 : AV_PIX_FMT_MONOWHITE; @@ -96,15 +103,23 @@ static int sunrast_decode_frame(AVCodecContext *avctx, AVFrame *p, return AVERROR_INVALIDDATA; } + // This checks w and h to be valid in the sense that bytes of a padded bitmap are addressable with 32bit int ret = ff_set_dimensions(avctx, w, h); if (ret < 0) return ret; + // ensured by ff_set_dimensions() + av_assert0(w <= (INT32_MAX - 7) / depth); + /* scanlines are aligned on 16 bit boundaries */ len = (depth * w + 7) >> 3; alen = len + (len & 1); - if (buf_end - buf < maplength + (len * h) * 3 / 256) + // ensured by ff_set_dimensions() + av_assert0(h <= INT32_MAX / (3 * len)); + + // maplength is limited to 768 and the right term is limited to INT32_MAX / 256 so the add needs no check + if (buf_end - buf < (uint64_t)maplength + (len * h) * 3 / 256) return AVERROR_INVALIDDATA; if ((ret = ff_get_buffer(avctx, p, 0)) < 0) @@ -118,7 +133,7 @@ static int sunrast_decode_frame(AVCodecContext *avctx, AVFrame *p, } else if (maplength) { unsigned int len = maplength / 3; - if (maplength % 3 || maplength > 768) { + if (maplength % 3) { av_log(avctx, AV_LOG_WARNING, "invalid colormap length\n"); return AVERROR_INVALIDDATA; } -- 2.17.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".