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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B77BC433FE for ; Mon, 31 Jan 2022 15:37:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B31A26B00B7; Mon, 31 Jan 2022 10:37:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AE0F36B00B9; Mon, 31 Jan 2022 10:37:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F6EC8D0001; Mon, 31 Jan 2022 10:37:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 8C8576B00B7 for ; Mon, 31 Jan 2022 10:37:17 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 41078181CB150 for ; Mon, 31 Jan 2022 15:37:17 +0000 (UTC) X-FDA: 79090986114.30.44D839E Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf24.hostedemail.com (Postfix) with ESMTP id 45351180009 for ; Mon, 31 Jan 2022 15:37:16 +0000 (UTC) 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 ams.source.kernel.org (Postfix) with ESMTPS id 65B7CB82985; Mon, 31 Jan 2022 15:37:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 125E3C340E8; Mon, 31 Jan 2022 15:37:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643643433; bh=n4pF0WTD8mzI8jApP59+6mO09uKqNqOupqmX+4f7jRk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QO8bd6YwcVynrWLeUHJiup6FETqxBrt5l8FJYwCvJs/JayrA0saN0XoC2+Yi4iOeb DnE+nmh6kh0XRjoqhy7B/yMAkmIZRcODgKjW2wcsOluZkn0tPXFfMePt1lZAMke6NL Kp9NuRE7JWzvN9/n6wSEZAOTfXcfsUZrDmTqwJidpsWC4365LQzisynhfF2+0bjd9X wdGeyI5gtwiMDs+jRdPq/DBG4vRKcN1JSHQRalDJcmVshoYq0d1uKiZtnLC9RtJdXq CgTYbUbzZI1e677E4tEko0HGJHCR856BNRlgglATA6+ZBd4SC2GWyTchpzPy7W+30T SpEc1n09nuJTw== Date: Mon, 31 Jan 2022 16:37:07 +0100 From: Christian Brauner To: Matthew Wilcox Cc: kernel test robot , Kees Cook , Ariadne Conill , 0day robot , Michael Kerrisk , Rich Felker , Eric Biederman , Alexander Viro , LKML , lkp@lists.01.org, Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [fs/exec] 80bd5afdd8: xfstests.generic.633.fail Message-ID: <20220131153707.oe45h7tuci2cbfuv@wittgenstein> References: <20220127000724.15106-1-ariadne@dereferenced.org> <20220131144352.GE16385@xsang-OptiPlex-9020> <20220131150819.iuqlz3rz6q7cheap@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Stat-Signature: rqps98ym8rptk3pbczrai768izga617r X-Rspam-User: nil Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=QO8bd6Yw; spf=pass (imf24.hostedemail.com: domain of brauner@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=brauner@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 45351180009 X-HE-Tag: 1643643436-527187 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jan 31, 2022 at 03:19:22PM +0000, Matthew Wilcox wrote: > On Mon, Jan 31, 2022 at 04:08:19PM +0100, Christian Brauner wrote: > > On Mon, Jan 31, 2022 at 10:43:52PM +0800, kernel test robot wrote: > > I can fix this rather simply in our upstream fstests with: > > > > static char *argv[] = { > > "", > > }; > > > > I guess. > > > > But doesn't > > > > static char *argv[] = { > > NULL, > > }; > > > > seem something that should work especially with execveat()? > > The problem is that the exec'ed program sees an argc of 0, which is the > problem we're trying to work around in the kernel (instead of leaving > it to ld.so to fix for suid programs). Ok, just seems a bit more intuitive for path-based exec than for fd-based execveat(). What's argv[0] supposed to contain in these cases? 1. execveat(fd, NULL, ..., AT_EMPTY_PATH) 2. execveat(fd, "my-file", ..., ) "" in both 1. and 2.? "" in 1. and "my-file" in 2.?