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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 32B5BC43441 for ; Sun, 11 Nov 2018 20:13:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00A572080D for ; Sun, 11 Nov 2018 20:13:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00A572080D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk 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 S1731604AbeKLGCi (ORCPT ); Mon, 12 Nov 2018 01:02:38 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52686 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726709AbeKLGCi (ORCPT ); Mon, 12 Nov 2018 01:02:38 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvt7-0000lK-M0; Sun, 11 Nov 2018 19:59:17 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsQ-0001SO-1e; Sun, 11 Nov 2018 19:58:34 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Eric Biggers" , "Theodore Ts'o" , "Andreas Dilger" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 079/366] ext4: don't read out of bounds when checking for in-inode xattrs In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 290ab230016f187c3551d8380ea742889276d03a upstream. With i_extra_isize equal to or close to the available space, it was possible for us to read past the end of the inode when trying to detect or validate in-inode xattrs. Fix this by checking for the needed extra space first. This patch shouldn't have any noticeable effect on non-corrupted/non-malicious filesystems. Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o Reviewed-by: Andreas Dilger [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- fs/ext4/inode.c | 4 +++- fs/ext4/xattr.c | 5 ++--- 2 files changed, 5 insertions(+), 4 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4165,7 +4165,9 @@ static inline void ext4_iget_extra_inode { __le32 *magic = (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize; - if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) { + if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <= + EXT4_INODE_SIZE(inode->i_sb) && + *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) { ext4_set_inode_state(inode, EXT4_STATE_XATTR); ext4_find_inline_data_nolock(inode); } else --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -247,13 +247,12 @@ static int __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header, void *end, const char *function, unsigned int line) { - struct ext4_xattr_entry *entry = IFIRST(header); int error = -EIO; - if (((void *) header >= end) || + if (end - (void *)header < sizeof(*header) + sizeof(u32) || (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC))) goto errout; - error = ext4_xattr_check_names(entry, end, entry); + error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header)); errout: if (error) __ext4_error_inode(inode, function, line, 0,