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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28520C4332F for ; Tue, 1 Feb 2022 13:28:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238679AbiBAN2z (ORCPT ); Tue, 1 Feb 2022 08:28:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238612AbiBAN2x (ORCPT ); Tue, 1 Feb 2022 08:28:53 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BC5FC061714; Tue, 1 Feb 2022 05:28:53 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 244D86154A; Tue, 1 Feb 2022 13:28:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 252C4C340EB; Tue, 1 Feb 2022 13:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643722132; bh=cXcPTewqmwfdy6WLzBYTm7mmiY7gQapV5gLUnxXuBJM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X8GRn9j/6VclNn2LaMi7ILPvNbU/WrXIIlXxEKwimOnwbWX9YeOOUylmsw61ESpXu pEVDMCNaVgxh1uZbW3sYgofCcZ2zIcSuq2GCl7lrU4fM65WJSONbV1PrFBn+L+eA3i fpXLXbrc0mbqhQfGIEW6Srqrnm8jYUtziPsBBRzZyMGCA90aFlUuQapvjqOvy2NT0k 9zYOwH6mwPO0EmOoUshgBFDcbaFg1mzurh6+EbcVw9lebGwFoakXr9DhdhRlZVvz4q x5MdzJGoCrl6HODSKJy9w0vrWhV8dk4ID11sxcfecfX2Xweb/rjQFiStiIfBD7ly0X yg9DwCidSsRIw== Date: Tue, 1 Feb 2022 14:28:46 +0100 From: Christian Brauner To: Kees Cook Cc: Andrew Morton , Matthew Wilcox , kernel test robot , Ariadne Conill , 0day robot , Michael Kerrisk , Rich Felker , Eric Biederman , Alexander Viro , LKML , lkp@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [fs/exec] 80bd5afdd8: xfstests.generic.633.fail Message-ID: <20220201132846.7rrkosqyeidij47w@wittgenstein> References: <20220127000724.15106-1-ariadne@dereferenced.org> <20220131144352.GE16385@xsang-OptiPlex-9020> <20220131150819.iuqlz3rz6q7cheap@wittgenstein> <20220131153707.oe45h7tuci2cbfuv@wittgenstein> <20220131161415.wlvtsd4ecehyg3x5@wittgenstein> <20220131171344.77iifun5wdilbqdz@wittgenstein> <20220131135940.20790cff1747e79dd855aaf4@linux-foundation.org> <202201311447.4A1CCAF@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <202201311447.4A1CCAF@keescook> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 31, 2022 at 02:49:36PM -0800, Kees Cook wrote: > On Mon, Jan 31, 2022 at 01:59:40PM -0800, Andrew Morton wrote: > > On Mon, 31 Jan 2022 18:13:44 +0100 Christian Brauner wrote: > > > > > > in other words, the changes that you see CMD_ARGS[0] == NULL for > > > > execveat() seem higher than for path-based exec. > > > > > > > > To counter that we should probably at least update the execveat() > > > > manpage with a recommendation what CMD_ARGS[0] should be set to if it > > > > isn't allowed to be set to NULL anymore. This is why was asking what > > > > argv[0] is supposed to be if the binary doesn't take any arguments. > > > > > > Sent a fix to our fstests now replacing the argv[0] as NULL with "". > > > > As we hit this check so quickly, I'm thinking that Ariadne's patch > > "fs/exec: require argv[0] presence in do_execveat_common()" (which > > added the check) isn't something we'll be able to merge into mainline? > > I think the next best would be to mutate an NULL argv into { "", NULL }. > However, I still think we should do the pr_warn(). > > Thoughts? +1