Return-Path: Received: from mail.kernel.org ([198.145.29.99]:51520 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730843AbeLFOqp (ORCPT ); Thu, 6 Dec 2018 09:46:45 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qu Wenruo , Nikolay Borisov , David Sterba , Ben Hutchings Subject: [PATCH 4.9 068/101] btrfs: Check if item pointer overlaps with the item itself Date: Thu, 6 Dec 2018 15:39:07 +0100 Message-Id: <20181206143015.734862750@linuxfoundation.org> In-Reply-To: <20181206143011.174892052@linuxfoundation.org> References: <20181206143011.174892052@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qu Wenruo commit 7f43d4affb2a254d421ab20b0cf65ac2569909fb upstream. Function check_leaf() checks if any item pointer points outside of the leaf, but it doesn't check if the pointer overlaps with the item itself. Normally only the last item may be the victim, but adding such check is never a bad idea anyway. Signed-off-by: Qu Wenruo Reviewed-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/disk-io.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -637,6 +637,13 @@ static noinline int check_leaf(struct bt return -EUCLEAN; } + /* Also check if the item pointer overlaps with btrfs item. */ + if (btrfs_item_nr_offset(slot) + sizeof(struct btrfs_item) > + btrfs_item_ptr_offset(leaf, slot)) { + CORRUPT("slot overlap with its data", leaf, root, slot); + return -EUCLEAN; + } + prev_key.objectid = key.objectid; prev_key.type = key.type; prev_key.offset = key.offset;