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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 128B0C4741F for ; Mon, 9 Nov 2020 13:09:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0C2E20789 for ; Mon, 9 Nov 2020 13:09:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927349; bh=GA0zwwui2qgUENftB8za4Im3485L53l9jiFKcf5d2NQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AHhbl0351vQbsKihbxjwqcIw3snLGSIEpZaNyTCSQ5ZywcX29tHNaCCgld5dZ1N2A /BtZRkQa30jiLZt8bAUkuRw9I6g40QDvncoKn+9RMmPhsuLXJ/q90vvQKP+E4YfggI rWGUbSp6Vk+xcnpLWyTGUDHKFJsEFzcqnVYIuxwo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731778AbgKINJI (ORCPT ); Mon, 9 Nov 2020 08:09:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:33936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731766AbgKINJC (ORCPT ); Mon, 9 Nov 2020 08:09:02 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ECE2220663; Mon, 9 Nov 2020 13:09:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927341; bh=GA0zwwui2qgUENftB8za4Im3485L53l9jiFKcf5d2NQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fwTFu4BbfWrJF0qCPz0Nue9Qz/V0tOLaKZL/UH660gM21j9i0fFsrfsM5ZWZxmAn9 n/UiZMBAiWDfFlPjLSYDT+WJZepVJXePkvq6Q2kgw0TYaCelnF/yuSuwhhH8puhFWK dGh94XxmoEVPS5iI7hfLU3JalUpGiX0AV3RkEXcM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yoon Jungyeon , Nikolay Borisov , Qu Wenruo , Johannes Thumshirn , David Sterba , Ben Hutchings Subject: [PATCH 4.19 26/71] btrfs: tree-checker: Verify dev item Date: Mon, 9 Nov 2020 13:55:20 +0100 Message-Id: <20201109125021.133720668@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125019.906191744@linuxfoundation.org> References: <20201109125019.906191744@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qu Wenruo commit ab4ba2e133463c702b37242560d7fabedd2dc750 upstream. [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 Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/tree-checker.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/volumes.c | 9 ----- fs/btrfs/volumes.h | 9 +++++ 3 files changed, 83 insertions(+), 9 deletions(-) --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -600,6 +600,77 @@ int btrfs_check_chunk_valid(struct btrfs return 0; } +__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); + return -EUCLEAN; + } + if (key->offset > max_devid) { + dev_item_err(fs_info, leaf, slot, + "invalid devid: has=%llu expect=[0, %llu]", + key->offset, max_devid); + return -EUCLEAN; + } + 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)); + return -EUCLEAN; + } + + /* + * For device total_bytes, we don't have reliable way to check it, as + * it can be 0 for device removal. Device size check can only be done + * by dev extents check. + */ + 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)); + return -EUCLEAN; + } + /* + * Remaining members like io_align/type/gen/dev_group aren't really + * utilized. Skip them to make later usage of them easier. + */ + return 0; +} + /* * Common point to switch the item-specific validation. */ @@ -630,6 +701,9 @@ static int check_leaf_item(struct btrfs_ 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; } --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4606,15 +4606,6 @@ static void check_raid56_incompat_flag(s 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) { --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -257,6 +257,15 @@ 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).