From patchwork Tue Jul 3 07:58:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 10503403 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 33299601D3 for ; Tue, 3 Jul 2018 07:58:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2554A289C2 for ; Tue, 3 Jul 2018 07:58:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1745F28A11; Tue, 3 Jul 2018 07:58:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A6C8D289C2 for ; Tue, 3 Jul 2018 07:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753892AbeGCH6Z (ORCPT ); Tue, 3 Jul 2018 03:58:25 -0400 Received: from mx2.suse.de ([195.135.220.15]:48394 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753364AbeGCH6Z (ORCPT ); Tue, 3 Jul 2018 03:58:25 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 399EEACE2 for ; Tue, 3 Jul 2018 07:58:24 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: tree-checker: Detect invalid empty essential tree Date: Tue, 3 Jul 2018 15:58:16 +0800 Message-Id: <20180703075816.6196-1-wqu@suse.com> X-Mailer: git-send-email 2.18.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Reported in https://bugzilla.kernel.org/show_bug.cgi?id=199847, where the crafted image has empty root tree block, which will cause later NULL pointer dereference. The following trees should never be empty: 1) Tree root Must contain at least root items for extent tree, device tree and fs tree 2) Chunk tree Or we can't even bootstrap. 3) Fs tree At least inode item for top level inode (.). 4) Device tree Dev extents for chunks 5) Extent tree Must has corresponding extent for each chunk. If any is empty, we are sure the fs is corrupted and no need to mount it. Reported-by: Xu Wen Signed-off-by: Qu Wenruo --- fs/btrfs/tree-checker.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 1cd735b099df..3a307efab46b 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -497,8 +497,20 @@ static int check_leaf(struct btrfs_fs_info *fs_info, struct extent_buffer *leaf, * skip this check for relocation trees. */ if (nritems == 0 && !btrfs_header_flag(leaf, BTRFS_HEADER_FLAG_RELOC)) { + u64 owner = btrfs_header_owner(leaf); struct btrfs_root *check_root; + /* These trees should never be empty */ + if (owner == BTRFS_ROOT_TREE_OBJECTID || + owner == BTRFS_CHUNK_TREE_OBJECTID || + owner == BTRFS_EXTENT_TREE_OBJECTID || + owner == BTRFS_DEV_TREE_OBJECTID || + owner == BTRFS_FS_TREE_OBJECTID) { + generic_err(fs_info, leaf, 0, + "invalid root, root %llu should never be empty", + owner); + return -EUCLEAN; + } key.objectid = btrfs_header_owner(leaf); key.type = BTRFS_ROOT_ITEM_KEY; key.offset = (u64)-1;