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 4A6C345493 for ; Wed, 1 Mar 2023 19:07:13 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 088C168B076; Wed, 1 Mar 2023 21:07:10 +0200 (EET) Received: from mail-oi1-f182.google.com (mail-oi1-f182.google.com [209.85.167.182]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 7071168A916 for ; Wed, 1 Mar 2023 21:07:03 +0200 (EET) Received: by mail-oi1-f182.google.com with SMTP id r40so10613836oiw.0 for ; Wed, 01 Mar 2023 11:07:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=t4yvOiJp7h3iKLjwOaq8mZZtY4lqWs/Juvy+sZTLYDs=; b=VBtUyDRmhZkXeHGI7+RBnCzbSjooh9bc2MzeldDBCVqxXzk8/2Sv2BnLM+Of/3756v GfX2p7Zv9S9pORz5WW+E+PwdlZ8sMY9jbaeosmMT1T1oN3ogox4FgKLkoZJfjkVhbGEJ KG1JhuydvIvcvCh4B3IumiNN0WSfGgOOZYm1GkJB7JXaVkCUvT24G9JC0hS0EZ3FPFdF KGVDA8DoBNpjFmgsccE9Eqa+GhKaEEktlkiRFfCaXx6NhU8ubuAFc8/uAERCmrAp+dj3 W+w45fRgYF7TYavDYosrGuRlBM9l7lvTB/7HkLIkM4GuEsIKngEwTsz1BiTP53x4pSV4 XUnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=t4yvOiJp7h3iKLjwOaq8mZZtY4lqWs/Juvy+sZTLYDs=; b=iuWVxfFtPEM2awsACfV8vuGDRER9gukr+jjbz9vcYalgI28DzRHi+THi/OTvFoj4O2 oK/qiOgzGH/gV2wnitt1x3r5Imr1tHMmkXG5i+/ieJhdvwUY50aoR/49YUj7wGtZaoeP vYHzklsFyEr9RyBWdTcO0cgLcD1WLa+kx4D/dzMNEcOk82wvWrcS0CQXWtyAd3m0NxMi IKcdG4PzBG6689BFcR7wCXjqeitS4m1wR+fTYrUx9eaWgbeWY3lEVFkB9PeAttqnTcwV 1A0dXuINRueZTMMHBzH198DfnYDRbYfxYstVq7xYAcYxt4YFiQAzXOWxsgfAbByIxnMV ncYQ== X-Gm-Message-State: AO0yUKV5qvezi6OcCEirxwAu/HFojxkKMRXyACBq4nhbNGH9RudiRQ7H 1ypjRV7EZgwomlNYdN7Y7hs+dmp1FTk= X-Google-Smtp-Source: AK7set/eJ/LI+/ph4jwWAK49fu0okCH+y73rSErD7uBsBJew0x88qqIaEEZM9sGt77OoyxbEcRIXIA== X-Received: by 2002:aca:1216:0:b0:383:b2bb:1212 with SMTP id 22-20020aca1216000000b00383b2bb1212mr3820450ois.4.1677697621527; Wed, 01 Mar 2023 11:07:01 -0800 (PST) Received: from [192.168.0.14] (host197.190-225-105.telecom.net.ar. [190.225.105.197]) by smtp.gmail.com with ESMTPSA id o7-20020acabe07000000b00383b2b6f453sm6162345oif.35.2023.03.01.11.07.00 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 01 Mar 2023 11:07:01 -0800 (PST) Message-ID: <8592e078-de2d-4bb8-9e60-872a0328fb5b@gmail.com> Date: Wed, 1 Mar 2023 16:07:10 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Content-Language: en-US To: ffmpeg-devel@ffmpeg.org References: <20230301185008.2167529-1-jdorfman@google.com> From: James Almer In-Reply-To: <20230301185008.2167529-1-jdorfman@google.com> Subject: Re: [FFmpeg-devel] [PATCH] libavcodec/h264dec: avoid arithmetic on null pointers 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 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On 3/1/2023 3:50 PM, Jeremy Dorfman wrote: > null pointer arithmetic is undefined behavior in C. > --- > libavcodec/h264dec.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c > index 2d691731c5..ef698f2630 100644 > --- a/libavcodec/h264dec.c > +++ b/libavcodec/h264dec.c > @@ -912,8 +912,8 @@ static int finalize_frame(H264Context *h, AVFrame *dst, H264Picture *out, int *g > av_log(h->avctx, AV_LOG_DEBUG, "Duplicating field %d to fill missing\n", field); > > for (p = 0; p<4; p++) { > - dst_data[p] = f->data[p] + (field^1)*f->linesize[p]; > - src_data[p] = f->data[p] + field *f->linesize[p]; > + dst_data[p] = f->data[p] ? f->data[p] + (field^1)*f->linesize[p] : NULL; > + src_data[p] = f->data[p] ? f->data[p] + field *f->linesize[p] : NULL; > linesizes[p] = 2*f->linesize[p]; > } Probably cleaner and clearer to do it like this: dst_data[p] = FF_PTR_ADD(f->data[p], (field^1)*f->linesize[p]); src_data[p] = FF_PTR_ADD(f->data[p], field *f->linesize[p]); _______________________________________________ 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".