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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 6BA13C3A5A3 for ; Tue, 27 Aug 2019 08:13:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4217F2184D for ; Tue, 27 Aug 2019 08:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566893582; bh=x2yaFsxyNtdZbvKQzpaUTp9W7h6k1yHSMcCMiTZWb6A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MrRWPV14K+uN6SDDIxUbGhTzri9OkodwaZC/EYGbyzzSPnxV89aFlPQMMzuzxSxCf QsRI3I0IgVVQ/ILBw0kZMjcOzk6bSY489x9Zj4gfhKg8yKhrmDCDAkkG/DTcQ1VoYW rLqgFAhrwGKz6B/fLe8TrdZpFu8JeuztqEGiWrZ0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731059AbfH0H6n (ORCPT ); Tue, 27 Aug 2019 03:58:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:51620 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730706AbfH0H6l (ORCPT ); Tue, 27 Aug 2019 03:58:41 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 025E4206BF; Tue, 27 Aug 2019 07:58:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566892720; bh=x2yaFsxyNtdZbvKQzpaUTp9W7h6k1yHSMcCMiTZWb6A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HatZyc0wqFWWcIFOPt6gdm+UzdiqIAkj/0Pxk+uaVgxg+qfmsU7VWk/t7mW+dfdE0 khQ86GyI5jVgrvEliP74JSH9VxwQb9vKkmNu2tDNDV3W5Ggcd27MSp+DYiiHPG9Z1h tVbRKtR5V5GcyKyeB0FJbstgA07bHFMglxxg49po= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brian Foster , "Darrick J. Wong" , Luis Chamberlain , Sasha Levin Subject: [PATCH 4.19 89/98] xfs: dont trip over uninitialized buffer on extent read of corrupted inode Date: Tue, 27 Aug 2019 09:51:08 +0200 Message-Id: <20190827072722.722033898@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190827072718.142728620@linuxfoundation.org> References: <20190827072718.142728620@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 6958d11f77d45db80f7e22a21a74d4d5f44dc667 upstream. We've had rather rare reports of bmap btree block corruption where the bmap root block has a level count of zero. The root cause of the corruption is so far unknown. We do have verifier checks to detect this form of on-disk corruption, but this doesn't cover a memory corruption variant of the problem. The latter is a reasonable possibility because the root block is part of the inode fork and can reside in-core for some time before inode extents are read. If this occurs, it leads to a system crash such as the following: BUG: unable to handle kernel paging request at ffffffff00000221 PF error: [normal kernel read fault] ... RIP: 0010:xfs_trans_brelse+0xf/0x200 [xfs] ... Call Trace: xfs_iread_extents+0x379/0x540 [xfs] xfs_file_iomap_begin_delay+0x11a/0xb40 [xfs] ? xfs_attr_get+0xd1/0x120 [xfs] ? iomap_write_begin.constprop.40+0x2d0/0x2d0 xfs_file_iomap_begin+0x4c4/0x6d0 [xfs] ? __vfs_getxattr+0x53/0x70 ? iomap_write_begin.constprop.40+0x2d0/0x2d0 iomap_apply+0x63/0x130 ? iomap_write_begin.constprop.40+0x2d0/0x2d0 iomap_file_buffered_write+0x62/0x90 ? iomap_write_begin.constprop.40+0x2d0/0x2d0 xfs_file_buffered_aio_write+0xe4/0x3b0 [xfs] __vfs_write+0x150/0x1b0 vfs_write+0xba/0x1c0 ksys_pwrite64+0x64/0xa0 do_syscall_64+0x5a/0x1d0 entry_SYSCALL_64_after_hwframe+0x49/0xbe The crash occurs because xfs_iread_extents() attempts to release an uninitialized buffer pointer as the level == 0 value prevented the buffer from ever being allocated or read. Change the level > 0 assert to an explicit error check in xfs_iread_extents() to avoid crashing the kernel in the event of localized, in-core inode corruption. Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Luis Chamberlain Signed-off-by: Sasha Levin --- fs/xfs/libxfs/xfs_bmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 3a496ffe6551c..ab2465bc413af 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -1178,7 +1178,10 @@ xfs_iread_extents( * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out. */ level = be16_to_cpu(block->bb_level); - ASSERT(level > 0); + if (unlikely(level == 0)) { + XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp); + return -EFSCORRUPTED; + } pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes); bno = be64_to_cpu(*pp); -- 2.20.1