From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELs4OHDCj1e3CocVPbpmSy6pf6VUmHwqHYGMEIhHz4+jAONBbD5AZiQoULeRChDc17mHAa+b ARC-Seal: i=1; a=rsa-sha256; t=1521738277; cv=none; d=google.com; s=arc-20160816; b=hj0N8JpwGUkAhSt3GWxnLThpFY9yqvKhwPiYY5Aw3jhjpVbv/A8ElWBM8yIGyYaUog PSXxe8N+ZPndufZ0f9Hyemgdd1ztaAdve0Lws54aMZXMpODmYZHYwPLtsH9Rk1MyBxst pNEocY2TO2G+tCx6Vh6tsrcqwuvyHuCJ+mBAi+TEnRNeHy/MVNKAj8D+9Ob2WRhGpJJX GqmjdIicKbniw+YfB1PrlF+7wHRvMMdelOoPzpsr+SRbeylpA/F+NZgxKiIJdDN+tygt WgYm2hCpHnVjCBQ2qjuU5P/51v89CwoX4vpailoT2bggLB/EFsypGyvAs4Zv55My7qCm /YNg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:references:in-reply-to:sender :mime-version:dkim-signature:dkim-signature:delivered-to:list-id :list-subscribe:list-unsubscribe:list-help:list-post:precedence :mailing-list:arc-authentication-results; bh=8iakfsKuLcka2vj5cjC5ZPB2nL5DjM1/05ZgYPZ+TAs=; b=liKi15ENWUeQcnNNSrVuLQOSj9klL2/4VwWvTVoxSvz43juH4wlniQXaZJn4dKVLGp YaiqjdYku+X1DOw427D6J6TgAZyh5GeCLJfvzLdJMSUw8S0OoD6TTJjXZbUqKLuNtvfm F/dLNplbrFTUJRC8hKD1MidZQAv8uT3+zReDBndZDE+5mdFUBGf5HiW3qrrzmFUqHWCT qUV4QDcO9v5QngUYF/vwjGwin9jgUTucOmOmJwnRp2KN7Ll4yLiQiKTZj0aKx0Dk7EHE r7Q/9se4r53/KhazDnSRADTzHWarVFW2PmIsLXxwUzKC5TyvMs0K8o2EbZ47jm8maGNi cKvQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=EWlFx/7K; dkim=pass header.i=@linux-foundation.org header.s=google header.b=S4HSt1m3; spf=pass (google.com: domain of kernel-hardening-return-12720-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12720-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=EWlFx/7K; dkim=pass header.i=@linux-foundation.org header.s=google header.b=S4HSt1m3; spf=pass (google.com: domain of kernel-hardening-return-12720-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12720-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: MIME-Version: 1.0 Sender: linus971@gmail.com In-Reply-To: References: <1521174359-46392-1-git-send-email-keescook@chromium.org> <20180316175502.GE30522@ZenIV.linux.org.uk> From: Linus Torvalds Date: Thu, 22 Mar 2018 10:04:14 -0700 X-Google-Sender-Auth: PBso_vYTCV7C_B-jyAybvlAnrrA Message-ID: Subject: Re: [PATCH v5 0/2] Remove false-positive VLAs when using max() To: Kees Cook Cc: Al Viro , Florian Weimer , Andrew Morton , Josh Poimboeuf , Rasmus Villemoes , Randy Dunlap , Miguel Ojeda , Ingo Molnar , David Laight , Ian Abbott , linux-input , linux-btrfs , Network Development , Linux Kernel Mailing List , Kernel Hardening Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1595034368078500739?= X-GMAIL-MSGID: =?utf-8?q?1595658236824951638?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, Mar 22, 2018 at 8:01 AM, Kees Cook wrote: > > Seems like it doesn't like void * arguments: Yeah, that was discussed separately, I just didn't realize we had any such users. As David said, just adding a (long) cast to it should be fine, ie #define __is_constant(a) \ (sizeof(int) == sizeof(*(1 ? ((void*)((long)(a) * 0l)) : (int*)1))) and is probably a good idea even outside of pointers (because "long long" constants could cause warnings too due to the cast to (void *)). Linus