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 Received: from picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 25C48C4321E for ; Tue, 29 Nov 2022 11:47:16 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id 473103CC5B1 for ; Tue, 29 Nov 2022 12:47:13 +0100 (CET) Received: from in-2.smtp.seeweb.it (in-2.smtp.seeweb.it [IPv6:2001:4b78:1:20::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 7EAE23C0162 for ; Tue, 29 Nov 2022 12:47:03 +0100 (CET) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-2.smtp.seeweb.it (Postfix) with ESMTPS id 5404B60024C for ; Tue, 29 Nov 2022 12:47:02 +0100 (CET) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8D05321B23; Tue, 29 Nov 2022 11:47:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1669722422; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BiIR0dLm6++9xnxIyc1lAlwp1dxO6759P7essKp53QE=; b=pGOgP6USSFvMcpjx6dbwSdOOh8yBEAhBFh6UmbXCiG9mej0PORt1CJgH8SkCQXDJWOhInX 061xlmpqkERJdOaqELx28HUw2FeybUaypAbuZwdLH7N0LPq8EM8tgLd/YYGIWp5gVi9R7L uGFRquuHieSm+P1DEmxX5l1Q9Me2bmM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1669722422; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BiIR0dLm6++9xnxIyc1lAlwp1dxO6759P7essKp53QE=; b=1cdZHOYHfiXkm5ddMOiv9P522AT/ecgwI8OYE1fxzgWyyBXO1h6SXxdoAWkKLmyY0oteen zYTc3OXKyUtR1oBg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 778F213428; Tue, 29 Nov 2022 11:47:02 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id i8PzGzbxhWOTcgAAMHmgww (envelope-from ); Tue, 29 Nov 2022 11:47:02 +0000 Date: Tue, 29 Nov 2022 12:48:21 +0100 From: Cyril Hrubis To: Tudor Cretu Message-ID: References: <20221123144746.590890-1-tudor.cretu@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221123144746.590890-1-tudor.cretu@arm.com> X-Virus-Scanned: clamav-milter 0.102.4 at in-2.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH 0/3] safe_macros: Fix undefined behaviour in vararg handling X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hi! > Accessing elements in an empty va_list results in undefined behaviour[0] > that can include accessing arbitrary stack memory. While typically this > doesn't raise a fault, some new more security-oriented architectures > (e.g. CHERI[1] or Morello[2]) don't allow it. Looking at how glibc handles this, the code looks like: int mode = 0; if (__OPEN_NEEDS_MODE(oflag)) { .. mode = va_arg(arg, int); .. } That sounds much easier than messing with the macros and should avoid undefined behavior. -- Cyril Hrubis chrubis@suse.cz -- Mailing list info: https://lists.linux.it/listinfo/ltp