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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99C54EB64DD for ; Sun, 13 Aug 2023 21:32:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231969AbjHMVcc (ORCPT ); Sun, 13 Aug 2023 17:32:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231966AbjHMVcb (ORCPT ); Sun, 13 Aug 2023 17:32:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95C6410DB for ; Sun, 13 Aug 2023 14:32:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 33F3962BD7 for ; Sun, 13 Aug 2023 21:32:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25974C433C7; Sun, 13 Aug 2023 21:32:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691962352; bh=l0+mI2gbfrg3yVM5mk2EVIPZzOyoFKEDU34FGa0s0fE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iq5zA6nCYtQWRgDTHFkF6LeMNAYQhcYrJXgpdZEG1sVZjlpbybEHlbO7IHKpbQX9l 3DWKkwCD2O0uGFU4Xyi1xgjP+hat3ITQX8ONUWAEZJ2T2KqdBvGJJb0j7OIDdSB4Kx +a4vQp6vl4qTrEfM0NXiTuKOHaETD7niPIserlvA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+ae97a827ae1c3336bbb4@syzkaller.appspotmail.com, Filipe Manana , Qu Wenruo , David Sterba Subject: [PATCH 6.4 187/206] btrfs: reject invalid reloc tree root keys with stack dump Date: Sun, 13 Aug 2023 23:19:17 +0200 Message-ID: <20230813211730.374396276@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230813211724.969019629@linuxfoundation.org> References: <20230813211724.969019629@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Qu Wenruo commit 6ebcd021c92b8e4b904552e4d87283032100796d upstream. [BUG] Syzbot reported a crash that an ASSERT() got triggered inside prepare_to_merge(). That ASSERT() makes sure the reloc tree is properly pointed back by its subvolume tree. [CAUSE] After more debugging output, it turns out we had an invalid reloc tree: BTRFS error (device loop1): reloc tree mismatch, root 8 has no reloc root, expect reloc root key (-8, 132, 8) gen 17 Note the above root key is (TREE_RELOC_OBJECTID, ROOT_ITEM, QUOTA_TREE_OBJECTID), meaning it's a reloc tree for quota tree. But reloc trees can only exist for subvolumes, as for non-subvolume trees, we just COW the involved tree block, no need to create a reloc tree since those tree blocks won't be shared with other trees. Only subvolumes tree can share tree blocks with other trees (thus they have BTRFS_ROOT_SHAREABLE flag). Thus this new debug output proves my previous assumption that corrupted on-disk data can trigger that ASSERT(). [FIX] Besides the dedicated fix and the graceful exit, also let tree-checker to check such root keys, to make sure reloc trees can only exist for subvolumes. CC: stable@vger.kernel.org # 5.15+ Reported-by: syzbot+ae97a827ae1c3336bbb4@syzkaller.appspotmail.com Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/disk-io.c | 3 ++- fs/btrfs/tree-checker.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 1 deletion(-) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1351,7 +1351,8 @@ static int btrfs_init_fs_root(struct btr btrfs_drew_lock_init(&root->snapshot_lock); if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID && - !btrfs_is_data_reloc_root(root)) { + !btrfs_is_data_reloc_root(root) && + is_fstree(root->root_key.objectid)) { set_bit(BTRFS_ROOT_SHAREABLE, &root->state); btrfs_check_and_init_root_item(&root->root_item); } --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -446,6 +446,20 @@ static int check_root_key(struct extent_ btrfs_item_key_to_cpu(leaf, &item_key, slot); is_root_item = (item_key.type == BTRFS_ROOT_ITEM_KEY); + /* + * Bad rootid for reloc trees. + * + * Reloc trees are only for subvolume trees, other trees only need + * to be COWed to be relocated. + */ + if (unlikely(is_root_item && key->objectid == BTRFS_TREE_RELOC_OBJECTID && + !is_fstree(key->offset))) { + generic_err(leaf, slot, + "invalid reloc tree for root %lld, root id is not a subvolume tree", + key->offset); + return -EUCLEAN; + } + /* No such tree id */ if (unlikely(key->objectid == 0)) { if (is_root_item)