From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70034C3A5A2 for ; Fri, 23 Aug 2019 15:16:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43416206E0 for ; Fri, 23 Aug 2019 15:16:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RDruYcE+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404489AbfHWPQC (ORCPT ); Fri, 23 Aug 2019 11:16:02 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:45078 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394059AbfHWPQC (ORCPT ); Fri, 23 Aug 2019 11:16:02 -0400 Received: by mail-wr1-f68.google.com with SMTP id q12so8941944wrj.12 for ; Fri, 23 Aug 2019 08:16:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=ODT+/U9gABWnjCeKmMszPjjU9b48kuGYC8y2/yEEfuM=; b=RDruYcE+mmtUh214dp7OcyRv6u9FdOJdceLedKP9JjA86qAa3pzg2nSlUGeQD+iL9q mxikmaO3uHEwFwuBnzJH7MklC1JMoeazim2G2yJZ8ttqaPuRHEU37guZ0qY5qYbwinzU bDN1ro1mwhbcQgLvmAv3N7kBwurwBPJPoHVxvjGAgHd/90DHNouN0+B2AK6iuX++LqTv z2Pyu9F2/OgDLRHh1ZAw9sHUzWUPsOkDeQxlpTzU8weZgbHfzz5unpbZqJa9ZZnULLDw jp7H8mzLwq9LxvMJ2xuRS2v+FkwCu7W1V6GJgfI8yYbG/u7jbX06a1pWOFHnWD+ZEqR8 NLIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:in-reply-to :message-id:references:user-agent:mime-version; bh=ODT+/U9gABWnjCeKmMszPjjU9b48kuGYC8y2/yEEfuM=; b=WtWWd72FR31wvcpxK+X+HP65JcVmp8B2FiNzjXF4kBWQlJFVDy2ADtxBH2DxypBZ1r DbuBEqMGp/PXtxf4UDamZwN6aCgRqpVKPvfFr5NsS/Dk8qc6epku0QBxV7ZFjEtueXG3 caRnRPaVI9rf2wBvRykFKu4DWfkrjCWdJgLnhGGjgtBUQEWoNfctosmpQmgtu0EYBu31 Y+/MAOgJIQNeBqvUkCox4bjcyeXwSw1B0x7mr6mdAoNy7WjICcQMFiGNul2dAjHQdtHg l0fc8kNPka8LoM3CMnLKNSgtxufYrHHdpwOq8bJPybKitfmtsrfIT/5wqF226wZBmy3i sv9Q== X-Gm-Message-State: APjAAAUWFbWYqleRX6Z4wIZBedeVxG0+0xt5iF6C70Dd8pXH8bts5i1s FRgzt5ywWuyUnOUcjJPf+6g= X-Google-Smtp-Source: APXvYqxsSOTX50kXNi0JI5WGqHj42IFVzEzCqL/k6JaoxOxSWqWUL7l1/UNpmIClFx+6BvVSLCgrxA== X-Received: by 2002:adf:fc51:: with SMTP id e17mr5915806wrs.348.1566573360365; Fri, 23 Aug 2019 08:16:00 -0700 (PDT) Received: from planxty ([2a02:8108:1700:19dc:b567:5617:6bc1:51bb]) by smtp.gmail.com with ESMTPSA id j9sm4068257wrx.66.2019.08.23.08.15.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Aug 2019 08:15:59 -0700 (PDT) Date: Fri, 23 Aug 2019 17:15:58 +0200 (CEST) From: John Kacur X-X-Sender: jkacur@planxty To: Daniel Wagner cc: Clark Williams , linux-rt-users@vger.kernel.org Subject: Re: [PATCH rt-tests v1 v1 1/4] pmqtest: Increase buffer to avoid overflow In-Reply-To: <20190819064304.4676-2-wagi@monom.org> Message-ID: References: <20190819064304.4676-1-wagi@monom.org> <20190819064304.4676-2-wagi@monom.org> User-Agent: Alpine 2.21 (LFD 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="-1463804494-1291524723-1566573359=:7154" Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---1463804494-1291524723-1566573359=:7154 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT On Mon, 19 Aug 2019, Daniel Wagner wrote: > Increase the size of the char buffer. gcc 9.1.1 reports: > > src/pmqtest/pmqtest.c: In function ‘main’: > src/pmqtest/pmqtest.c:46:21: warning: ‘%d’ directive writing between 1 and 10 bytes into a region of size 8 [-Wformat-overflow=] > 46 | #define SYNCMQ_NAME "/syncmsg%d" > | ^~~~~~~~~~~~ > > src/pmqtest/pmqtest.c:445:3: note: ‘sprintf’ output between 10 and 19 bytes into a destination of size 16 > 445 | sprintf(mqname, SYNCMQ_NAME, i); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Signed-off-by: Daniel Wagner > --- > src/pmqtest/pmqtest.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/src/pmqtest/pmqtest.c b/src/pmqtest/pmqtest.c > index a04fc49872bf..3ce799bd6319 100644 > --- a/src/pmqtest/pmqtest.c > +++ b/src/pmqtest/pmqtest.c > @@ -440,7 +440,7 @@ int main(int argc, char *argv[]) > goto nomem; > > for (i = 0; i < num_threads; i++) { > - char mqname[16]; > + char mqname[19]; > > sprintf(mqname, SYNCMQ_NAME, i); > receiver[i].syncmq = mq_open(mqname, oflag, 0777, &mqstat); > @@ -567,7 +567,7 @@ int main(int argc, char *argv[]) > } > nanosleep(&maindelay, NULL); > for (i = 0; i < num_threads; i++) { > - char mqname[16]; > + char mqname[19]; > > mq_close(receiver[i].syncmq); > sprintf(mqname, SYNCMQ_NAME, i); > -- > 2.21.0 > I don't love the use of "magic numbers". Also the compiler considers the signed integers to be −2147483648 to 2147483647 so including the sign that is potentially up to 11 chars, plus our string is "/syncmsg" is 8 chars so that's where the 19 comes from. However we are using the int to represent threads, so we know we can't have a negative number. However sprintf also adds '\n' which brings us back to 19 again anyway. This is better than what we have, so Signed-off-by: John Kacur ---1463804494-1291524723-1566573359=:7154--