From patchwork Mon Jul 16 23:00:50 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: dann frazier X-Patchwork-Id: 944623 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41TzRh32wCz9s3x; Tue, 17 Jul 2018 09:01:20 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1ffCUT-0006MA-Gs; Mon, 16 Jul 2018 23:01:13 +0000 Received: from complete.lackof.org ([198.49.126.79]) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1ffCUR-0006LH-BT for kernel-team@lists.ubuntu.com; Mon, 16 Jul 2018 23:01:11 +0000 Received: from localhost (c-73-78-137-212.hsd1.co.comcast.net [73.78.137.212]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by complete.lackof.org (Postfix) with ESMTPSA id 5D2C233E0243 for ; Mon, 16 Jul 2018 17:01:09 -0600 (MDT) From: dann frazier To: kernel-team@lists.ubuntu.com Subject: [PATCH 2/2][Cosmic][SRU Bionic] UBUNTU: SAUCE: ext4: check for allocation block validity with block group locked Date: Mon, 16 Jul 2018 17:00:50 -0600 Message-Id: <20180716230050.24741-3-dann.frazier@canonical.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180716230050.24741-1-dann.frazier@canonical.com> References: <20180716230050.24741-1-dann.frazier@canonical.com> X-Virus-Scanned: clamav-milter 0.100.0 at complete.lackof.org X-Virus-Status: Clean X-Spam-Status: No, score=0.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on complete.lackof.org X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Theodore Ts'o BugLink: https://bugs.launchpad.net/bugs/1781709 With commit 044e6e3d74a3: "ext4: don't update checksum of new initialized bitmaps" the buffer valid bit will get set without actually setting up the checksum for the allocation bitmap, since the checksum will get calculated once we actually allocate an inode or block. If we are doing this, then we need to (re-)check the verified bit after we take the block group lock. Otherwise, we could race with another process reading and verifying the bitmap, which would then complain about the checksum being invalid. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1780137 Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: dann frazier --- fs/ext4/balloc.c | 3 +++ fs/ext4/ialloc.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index e3d4f451d2cf6..57ab866847c02 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -383,6 +383,8 @@ static int ext4_validate_block_bitmap(struct super_block *sb, return -EFSCORRUPTED; ext4_lock_group(sb, block_group); + if (buffer_verified(bh)) + goto verified; if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, desc, bh))) { ext4_unlock_group(sb, block_group); @@ -405,6 +407,7 @@ static int ext4_validate_block_bitmap(struct super_block *sb, return -EFSCORRUPTED; } set_buffer_verified(bh); +verified: ext4_unlock_group(sb, block_group); return 0; } diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 555931386375b..b5e2cc28af470 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -91,6 +91,8 @@ static int ext4_validate_inode_bitmap(struct super_block *sb, return -EFSCORRUPTED; ext4_lock_group(sb, block_group); + if (buffer_verified(bh)) + goto verified; blk = ext4_inode_bitmap(sb, desc); if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh, EXT4_INODES_PER_GROUP(sb) / 8)) { @@ -108,6 +110,7 @@ static int ext4_validate_inode_bitmap(struct super_block *sb, return -EFSBADCRC; } set_buffer_verified(bh); +verified: ext4_unlock_group(sb, block_group); return 0; }