From patchwork Mon Jul 2 08:34:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 10500701 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 631F660325 for ; Mon, 2 Jul 2018 08:34:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5453B27FAC for ; Mon, 2 Jul 2018 08:34:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4855328390; Mon, 2 Jul 2018 08:34:25 +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 B603627FAC for ; Mon, 2 Jul 2018 08:34:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964803AbeGBIeX (ORCPT ); Mon, 2 Jul 2018 04:34:23 -0400 Received: from mx2.suse.de ([195.135.220.15]:46188 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933534AbeGBIeS (ORCPT ); Mon, 2 Jul 2018 04:34:18 -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 4D0FCAD1E for ; Mon, 2 Jul 2018 08:34:16 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v2] btrfs: tree-checker: Verify block_group_item Date: Mon, 2 Jul 2018 16:34:14 +0800 Message-Id: <20180702083414.13670-1-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 As reported in https://bugzilla.kernel.org/show_bug.cgi?id=199849, a crafted image with invalid block group items could make free space cache code to cause panic. We could early detect such invalid block group item by checking: 1) Size (key) We have a up limit on block group item (10G) 2) Chunk objectid 3) Type Exactly 1 bit set for type and no more than 1 bit set for profile 4) Used space No more than block group size. This should allow btrfs to detect and refuse to mount the crafted image. Reported-by: Xu Wen Signed-off-by: Qu Wenruo Reviewed-by: Nikolay Borisov --- changelog: v2: Format change for if() code block, added one new line for each block. Use "hweight64() > 1" to detect profile error, replacing the bloated !(flags & MASK == 0 || hweight64() == 1) condition. --- fs/btrfs/tree-checker.c | 92 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 8d40e7dd8c30..d4f872682668 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -353,6 +353,95 @@ static int check_dir_item(struct btrfs_fs_info *fs_info, return 0; } +__printf(4, 5) +__cold +static void block_group_err(const struct btrfs_fs_info *fs_info, + const struct extent_buffer *eb, int slot, + const char *fmt, ...) +{ + struct btrfs_key key; + struct va_format vaf; + va_list args; + + btrfs_item_key_to_cpu(eb, &key, slot); + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + btrfs_crit(fs_info, + "corrupt %s: root=%llu block=%llu slot=%d bg_start=%llu bg_len=%llu, %pV", + btrfs_header_level(eb) == 0 ? "leaf" : "node", + btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot, + key.objectid, key.offset, &vaf); + va_end(args); +} + +static int check_block_group_item(struct btrfs_fs_info *fs_info, + struct extent_buffer *leaf, + struct btrfs_key *key, int slot) +{ + struct btrfs_block_group_item bgi; + u32 item_size = btrfs_item_size_nr(leaf, slot); + u64 flags; + + /* + * Here we don't really care about unalignment since extent allocator + * can handle it. + * We care more about the size, as if one block group is larger than + * maximum size, it's must be some obvious corruption + */ + if (key->offset > 10ULL * SZ_1G) { + block_group_err(fs_info, leaf, slot, + "invalid block group size, have %llu expect (0, %llu)", + key->offset, 10ULL * SZ_1G); + return -EUCLEAN; + } + + if (item_size != sizeof(bgi)) { + block_group_err(fs_info, leaf, slot, + "invalid item size, have %u expect %lu", + item_size, sizeof(bgi)); + return -EUCLEAN; + } + + read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot), + sizeof(bgi)); + if (btrfs_block_group_chunk_objectid(&bgi) != + BTRFS_FIRST_CHUNK_TREE_OBJECTID) { + block_group_err(fs_info, leaf, slot, + "invalid block group chunk objectid, have %llu expect %llu", + btrfs_block_group_chunk_objectid(&bgi), + BTRFS_FIRST_CHUNK_TREE_OBJECTID); + return -EUCLEAN; + } + + if (btrfs_block_group_used(&bgi) > key->offset) { + block_group_err(fs_info, leaf, slot, + "invalid block group used, have %llu expect [0, %llu)", + btrfs_block_group_used(&bgi), key->offset); + return -EUCLEAN; + } + + flags = btrfs_block_group_flags(&bgi); + if (hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) > 1) { + block_group_err(fs_info, leaf, slot, +"invalid profile flags, have 0x%llx (%lu bits set) expect no more than 1 bit set", + flags & BTRFS_BLOCK_GROUP_PROFILE_MASK, + hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)); + return -EUCLEAN; + } + + if (hweight64(flags & BTRFS_BLOCK_GROUP_TYPE_MASK) != 1) { + block_group_err(fs_info, leaf, slot, +"invalid type flags, have 0x%llx (%lu bits set) expect exactly 1 bit set", + flags & BTRFS_BLOCK_GROUP_TYPE_MASK, + hweight64(flags & BTRFS_BLOCK_GROUP_TYPE_MASK)); + return -EUCLEAN; + } + return 0; +} + /* * Common point to switch the item-specific validation. */ @@ -374,6 +463,9 @@ static int check_leaf_item(struct btrfs_fs_info *fs_info, case BTRFS_XATTR_ITEM_KEY: ret = check_dir_item(fs_info, leaf, key, slot); break; + case BTRFS_BLOCK_GROUP_ITEM_KEY: + ret = check_block_group_item(fs_info, leaf, key, slot); + break; } return ret; }