From patchwork Mon Dec 28 12:51:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353575 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, USER_AGENT_GIT autolearn=ham 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 388F9C4332D for ; Mon, 28 Dec 2020 14:32:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 090DC208B6 for ; Mon, 28 Dec 2020 14:32:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503651AbgL1Obz (ORCPT ); Mon, 28 Dec 2020 09:31:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:39626 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2504403AbgL1ObY (ORCPT ); Mon, 28 Dec 2020 09:31:24 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6BA0D22573; Mon, 28 Dec 2020 14:30:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165844; bh=1xvNz+z0lFAd+OY6z96kpeCbnLJPAUZvH3SSCJdjepc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bydR/I2BAjcFVSAAoPh2wYSiZAdiuvOLIFh3hJgCz1qd4DSeDxUHDIT6ZnHcYbwUZ mJGa+NZPx6El3r6SHMi5YoyzN4b7CUHN2JdxQ2DTtXSBhto2ZinmKyTt9riA8yMTA+ kN3vwM3+gSDF/Cw9JY+Cr/vSGOXXm7STvd2hyuLc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Aleksa Sarai , Christian Brauner Subject: [PATCH 5.10 673/717] openat2: reject RESOLVE_BENEATH|RESOLVE_IN_ROOT Date: Mon, 28 Dec 2020 13:51:11 +0100 Message-Id: <20201228125053.220476023@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Aleksa Sarai commit 398840f8bb935d33c64df4ec4fed77a7d24c267d upstream. This was an oversight in the original implementation, as it makes no sense to specify both scoping flags to the same openat2(2) invocation (before this patch, the result of such an invocation was equivalent to RESOLVE_IN_ROOT being ignored). This is a userspace-visible ABI change, but the only user of openat2(2) at the moment is LXC which doesn't specify both flags and so no userspace programs will break as a result. Fixes: fddb5d430ad9 ("open: introduce openat2(2) syscall") Signed-off-by: Aleksa Sarai Acked-by: Christian Brauner Cc: # v5.6+ Link: https://lore.kernel.org/r/20201027235044.5240-2-cyphar@cyphar.com Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman --- fs/open.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/open.c +++ b/fs/open.c @@ -1010,6 +1010,10 @@ inline int build_open_flags(const struct if (how->resolve & ~VALID_RESOLVE_FLAGS) return -EINVAL; + /* Scoping flags are mutually exclusive. */ + if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT)) + return -EINVAL; + /* Deal with the mode. */ if (WILL_CREATE(flags)) { if (how->mode & ~S_IALLUGO)