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 X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 8AD6AC3279B for ; Fri, 6 Jul 2018 05:56:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43C8E23F9F for ; Fri, 6 Jul 2018 05:56:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43C8E23F9F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934460AbeGFFv7 (ORCPT ); Fri, 6 Jul 2018 01:51:59 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33592 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934440AbeGFFvz (ORCPT ); Fri, 6 Jul 2018 01:51:55 -0400 Received: from localhost (D57D388D.static.ziggozakelijk.nl [213.125.56.141]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id CDE2DC8D; Fri, 6 Jul 2018 05:51:54 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jonathan Billings , David Howells , Sasha Levin Subject: [PATCH 4.14 46/61] afs: Fix directory permissions check Date: Fri, 6 Jul 2018 07:47:10 +0200 Message-Id: <20180706054714.105324259@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180706054712.332416244@linuxfoundation.org> References: <20180706054712.332416244@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit 378831e4daec75fbba6d3612bcf3b4dd00ddbf08 ] Doing faccessat("/afs/some/directory", 0) triggers a BUG in the permissions check code. Fix this by just removing the BUG section. If no permissions are asked for, just return okay if the file exists. Also: (1) Split up the directory check so that it has separate if-statements rather than if-else-if (e.g. checking for MAY_EXEC shouldn't skip the check for MAY_READ and MAY_WRITE). (2) Check for MAY_CHDIR as MAY_EXEC. Without the main fix, the following BUG may occur: kernel BUG at fs/afs/security.c:386! invalid opcode: 0000 [#1] SMP PTI ... RIP: 0010:afs_permission+0x19d/0x1a0 [kafs] ... Call Trace: ? inode_permission+0xbe/0x180 ? do_faccessat+0xdc/0x270 ? do_syscall_64+0x60/0x1f0 ? entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 00d3b7a4533e ("[AFS]: Add security support.") Reported-by: Jonathan Billings Signed-off-by: David Howells Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/afs/security.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) --- a/fs/afs/security.c +++ b/fs/afs/security.c @@ -323,18 +323,14 @@ int afs_permission(struct inode *inode, mask, access, S_ISDIR(inode->i_mode) ? "dir" : "file"); if (S_ISDIR(inode->i_mode)) { - if (mask & MAY_EXEC) { + if (mask & (MAY_EXEC | MAY_READ | MAY_CHDIR)) { if (!(access & AFS_ACE_LOOKUP)) goto permission_denied; - } else if (mask & MAY_READ) { - if (!(access & AFS_ACE_LOOKUP)) - goto permission_denied; - } else if (mask & MAY_WRITE) { + } + if (mask & MAY_WRITE) { if (!(access & (AFS_ACE_DELETE | /* rmdir, unlink, rename from */ AFS_ACE_INSERT))) /* create, mkdir, symlink, rename to */ goto permission_denied; - } else { - BUG(); } } else { if (!(access & AFS_ACE_LOOKUP))