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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 ACA11C6787C for ; Fri, 12 Oct 2018 17:15:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 745AB2077C for ; Fri, 12 Oct 2018 17:15:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gQDfm7IN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 745AB2077C Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727061AbeJMAsd (ORCPT ); Fri, 12 Oct 2018 20:48:33 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:39768 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725854AbeJMAsc (ORCPT ); Fri, 12 Oct 2018 20:48:32 -0400 Received: by mail-pl1-f195.google.com with SMTP id w14-v6so6221267plp.6 for ; Fri, 12 Oct 2018 10:15:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ujwWbrimNp669KOEB8if5RkxRpiCrikk2Qz5VOA/j6M=; b=gQDfm7IN81M960Ohrzsq4aoqd93BSCaPEZcF2sfrgrANy7gC5gGxReonl2EwxTCl/k dKWs62xXYmi/xdzeol/ZBE6rjEo507pq6v855f+7UQG0Nj7xPAkdnbjrmpG+tGsqcMPl EmgMn3sFwOc0BMqiGHt/wFuRT2DzC/RWT5OsKL9S+HkUeq1DTCiazsVWgm+NFoCZAGgN VL98vlVj9jyJ32CfxNOa9WxO43zjU0mWyKaFEpSm1hhU4a1Rje4aLCA4+TIe6BtA/x6V IOtVuHnlgmNSdd3dXe8rEXJAOmSsVvCveIFNHd9J0P692EbuhukRr8P/R8IpqID+qijz IfAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ujwWbrimNp669KOEB8if5RkxRpiCrikk2Qz5VOA/j6M=; b=BVlRAz8ViliUoWCJtsY5hca9IgMab8tffnG6gGkglfAqb4fqX8Ezop28GjXhXunIRo 5PE16w3bwTjrkLrz0CCzwaKOaRyn8rypBNcthd7RGSViLRsoR2eBoY0eAFcOlYw8NC3/ l0T9uyH1svYcz/qe79/leW1ks4LWp8yfnhin2zxSigwcnyCK7t38Ga3BGtaThMgsdj9s decYkq20r+I9kI5H6nH2n0xqdaXkwdaW5qWov02eoOpkcqI0JmCw6d07kNSOB6WIz8kW b9JMK9V6dnp7YV8n3TPKTNBsSjNkgz4I3Fhj2RwfOnORrqFgS8wJOqa1iF0aDN7fuASj FSkw== X-Gm-Message-State: ABuFfohX4kcL/bDnP5L1sYBBN+Zv31IkbRw0nrKzPGaje4fQ/cGkqNiQ g4pISJQNtMHv0mn7dO3c3SrYrL7mzkf7PaRQsYaAlA== X-Google-Smtp-Source: ACcGV60ERIB98QcruqfKMFipjqMuswzQ8amsEZFbwBlxZ/1c8Cdo0y84gfK978KgSLEqvymaf9Jr0YLKYlRwq+xWXuw= X-Received: by 2002:a17:902:109:: with SMTP id 9-v6mr6664670plb.320.1539364503709; Fri, 12 Oct 2018 10:15:03 -0700 (PDT) MIME-Version: 1.0 References: <1539274203.2623.56.camel@linux.vnet.ibm.com> <20181011203126.15338-1-ndesaulniers@google.com> <1539356751.2656.5.camel@linux.ibm.com> <1539357759.2656.7.camel@linux.ibm.com> <16de2bb3-815a-f534-4618-af854c906017@gmail.com> <1539359181.2656.13.camel@linux.ibm.com> <1539360075.2656.18.camel@linux.ibm.com> In-Reply-To: <1539360075.2656.18.camel@linux.ibm.com> From: Nick Desaulniers Date: Fri, 12 Oct 2018 10:14:52 -0700 Message-ID: Subject: Re: [PATCH] KEYS: trusted: fix -Wvarags warning To: jejb@linux.ibm.com Cc: denkenz@gmail.com, dhowells@redhat.com, Nathan Chancellor , Eric Biggers , zohar@linux.vnet.ibm.com, jmorris@namei.org, serge@hallyn.com, linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Fri, Oct 12, 2018 at 9:01 AM James Bottomley wrote: > > On Fri, 2018-10-12 at 10:53 -0500, Denis Kenzior wrote: > > Hi James, > > > > > > From the links provided in the patch it seems that one cannot > > > > pass char/float/short to va_start(). Fair enough. So if we make > > > > h3 an unsigned int, the issue goes away, no? > > > > > > For the current version of clang, yes. However, if we're fixing > > > this for good a char * pointer is the only guaranteed thing because > > > it mirrors current use in printf. > > > > > > > All right. I guess I wasn't aware that non-printf like variadic > > functions are now considered harmful or of the impending crusade > > against them :) > > It's not, it's just a maintainer issue: The original problem is because > we coded for gcc specifically; it doesn't complain and does the right > thing, so everyone was happy. Now Clang comes along and is unhappy > with this, so the question a good maintainer should ask is "how do I > fix this so it never comes back again?", not "what's the easiest > bandaid to get both Clang and gcc to work?" because the latter is how > we got here in the first place. Clang is simply pointing out that this is explicitly undefined behavior by the C90 spec. As such, not only may the implementation be different between compilers, but it is free to change between versions of the same compiler (I haven't witnessed such a case yet in my limited career, but I would never say never when it comes to relying on undefined behavior). > > James > > > But in the context of this patch, can we please use something less > > invasive than changing all the arguments around? Promoting h3 to a > > bool (if possible) or int/unsigned int would get my vote. > > > > Regards, > > -Denis > > > -- Thanks, ~Nick Desaulniers