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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 0CC2CC43381 for ; Wed, 20 Mar 2019 06:37:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF0EE2184E for ; Wed, 20 Mar 2019 06:37:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727725AbfCTGhd (ORCPT ); Wed, 20 Mar 2019 02:37:33 -0400 Received: from mx2.suse.de ([195.135.220.15]:40872 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727716AbfCTGhc (ORCPT ); Wed, 20 Mar 2019 02:37:32 -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 A37E4AC69; Wed, 20 Mar 2019 06:37:30 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: Yoon Jungyeon , Nikolay Borisov Subject: [PATCh v2 5/9] btrfs: tree-checker: Verify dev item Date: Wed, 20 Mar 2019 14:37:13 +0800 Message-Id: <20190320063717.31770-6-wqu@suse.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190320063717.31770-1-wqu@suse.com> References: <20190320063717.31770-1-wqu@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org [BUG] For fuzzed image whose DEV_ITEM has invalid total_bytes as 0, then kernel will just panic: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 #PF error: [normal kernel read fault] PGD 800000022b2bd067 P4D 800000022b2bd067 PUD 22b2bc067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 1106 Comm: mount Not tainted 5.0.0-rc8+ #9 RIP: 0010:btrfs_verify_dev_extents+0x2a5/0x5a0 Call Trace: open_ctree+0x160d/0x2149 btrfs_mount_root+0x5b2/0x680 [CAUSE] If device extent verification finds a deivce with 0 total_bytes, then it assumes it's a seed dummy, then search for seed devices. But in this case, there is no seed device at all, causing NULL pointer. [FIX] Since this is caused by fuzzed image, let's go the tree-check way, just add a new verification for device item. Reported-by: Yoon Jungyeon Link: https://bugzilla.kernel.org/show_bug.cgi?id=202691 Signed-off-by: Qu Wenruo Reviewed-by: Nikolay Borisov --- fs/btrfs/tree-checker.c | 83 +++++++++++++++++++++++++++++++++++++++++ fs/btrfs/volumes.c | 9 ----- fs/btrfs/volumes.h | 9 +++++ 3 files changed, 92 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 86dee12d7917..004219175f0c 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -602,6 +602,86 @@ int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info, } +__printf(4, 5) +__cold +static void dev_item_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 devid=%llu %pV", + btrfs_header_level(eb) == 0 ? "leaf" : "node", + btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot, + key.objectid, &vaf); + va_end(args); +} + +static int check_dev_item(struct btrfs_fs_info *fs_info, + struct extent_buffer *leaf, + struct btrfs_key *key, int slot) +{ + struct btrfs_dev_item *ditem; + u64 max_devid = max(BTRFS_MAX_DEVS(fs_info), BTRFS_MAX_DEVS_SYS_CHUNK); + + if (key->objectid != BTRFS_DEV_ITEMS_OBJECTID) { + dev_item_err(fs_info, leaf, slot, + "invalid objectid: has=%llu expect=%llu", + key->objectid, BTRFS_DEV_ITEMS_OBJECTID); + goto error; + } + if (key->offset > max_devid) { + dev_item_err(fs_info, leaf, slot, + "invalid devid: has=%llu expect=[0, %llu]", + key->offset, max_devid); + goto error; + } + ditem = btrfs_item_ptr(leaf, slot, struct btrfs_dev_item); + if (btrfs_device_id(leaf, ditem) != key->offset) { + dev_item_err(fs_info, leaf, slot, + "devid mismatch: key has=%llu item has=%llu", + key->offset, btrfs_device_id(leaf, ditem)); + goto error; + } + + /* + * Since btrfs device add doesn't check device size at all, we could + * have device item whose size is smaller than 1M which is useless, but + * still valid. + * So here we can only check the obviously wrong case. + */ + if (btrfs_device_total_bytes(leaf, ditem) == 0) { + dev_item_err(fs_info, leaf, slot, + "invalid total bytes: have 0"); + goto error; + } + if (btrfs_device_bytes_used(leaf, ditem) > + btrfs_device_total_bytes(leaf, ditem)) { + dev_item_err(fs_info, leaf, slot, + "invalid bytes used: have %llu expect [0, %llu]", + btrfs_device_bytes_used(leaf, ditem), + btrfs_device_total_bytes(leaf, ditem)); + goto error; + } + /* + * Remaining members like io_align/type/gen/dev_group aren't really + * utilized. + * Skip them to make later usage of them easier. + */ + return 0; +error: + return -EUCLEAN; +} + /* * Common point to switch the item-specific validation. */ @@ -632,6 +712,9 @@ static int check_leaf_item(struct btrfs_fs_info *fs_info, ret = btrfs_check_chunk_valid(fs_info, leaf, chunk, key->offset); break; + case BTRFS_DEV_ITEM_KEY: + ret = check_dev_item(fs_info, leaf, key, slot); + break; } return ret; } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 645ffc9c47b0..7510272408e8 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4958,15 +4958,6 @@ static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type) btrfs_set_fs_incompat(info, RAID56); } -#define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info) \ - - sizeof(struct btrfs_chunk)) \ - / sizeof(struct btrfs_stripe) + 1) - -#define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE \ - - 2 * sizeof(struct btrfs_disk_key) \ - - 2 * sizeof(struct btrfs_chunk)) \ - / sizeof(struct btrfs_stripe) + 1) - static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, u64 start, u64 type) { diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 3ad9d58d1b66..38ed94b77202 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -258,6 +258,15 @@ struct btrfs_fs_devices { #define BTRFS_BIO_INLINE_CSUM_SIZE 64 +#define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info) \ + - sizeof(struct btrfs_chunk)) \ + / sizeof(struct btrfs_stripe) + 1) + +#define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE \ + - 2 * sizeof(struct btrfs_disk_key) \ + - 2 * sizeof(struct btrfs_chunk)) \ + / sizeof(struct btrfs_stripe) + 1) + /* * we need the mirror number and stripe index to be passed around * the call chain while we are processing end_io (especially errors). -- 2.21.0