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 C6EB3C25B06 for ; Sun, 14 Aug 2022 15:42:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241071AbiHNPmV (ORCPT ); Sun, 14 Aug 2022 11:42:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38362 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241176AbiHNPkf (ORCPT ); Sun, 14 Aug 2022 11:40:35 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A4A021831; Sun, 14 Aug 2022 08:32:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8D65DB80B7E; Sun, 14 Aug 2022 15:32:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A209C433B5; Sun, 14 Aug 2022 15:32:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660491165; bh=MndWcP1tH2TdgPOXBHyOSON7mwvxcXIppAyDlJHNYAs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MdkDI9cjf465fKrOw30gYbRMABApII8gP6Ajpim298djmYbX7hphL6LF91jjd7ibo 0QOKDBQ5wCInhNO0EgohPStIBkxH/ll6UZ2InMJI+HM1pyWIgHy8llaIxcd+ZM4wQE WpTGxNW62pCbwgdGPGUU6DSacvOFqVtPaEv5tSEXwxEj8zGFA64w4pNfV4KTrHBEw9 g8umrJgTxcbawqKJqz515r4P//8zvB8lN96gBMzDiwcTVN9htqN/aCNH7YMag/pl0G GAoMVLJPqlQHBlDEhgHXeqzi11RvpuGFcKa4oFiqkgubklOXrjLYdAdp+38INKpxtZ a55jdptsbdhRg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Lukas Czerner , syzbot+15cd994e273307bf5cfa@syzkaller.appspotmail.com, Tadeusz Struk , Theodore Ts'o , Sasha Levin , adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org Subject: [PATCH AUTOSEL 5.18 55/56] ext4: block range must be validated before use in ext4_mb_clear_bb() Date: Sun, 14 Aug 2022 11:30:25 -0400 Message-Id: <20220814153026.2377377-55-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220814153026.2377377-1-sashal@kernel.org> References: <20220814153026.2377377-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Lukas Czerner [ Upstream commit 1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6 ] Block range to free is validated in ext4_free_blocks() using ext4_inode_block_valid() and then it's passed to ext4_mb_clear_bb(). However in some situations on bigalloc file system the range might be adjusted after the validation in ext4_free_blocks() which can lead to troubles on corrupted file systems such as one found by syzkaller that resulted in the following BUG kernel BUG at fs/ext4/ext4.h:3319! PREEMPT SMP NOPTI CPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014 RIP: 0010:ext4_free_blocks+0x95e/0xa90 Call Trace: ? lock_timer_base+0x61/0x80 ? __es_remove_extent+0x5a/0x760 ? __mod_timer+0x256/0x380 ? ext4_ind_truncate_ensure_credits+0x90/0x220 ext4_clear_blocks+0x107/0x1b0 ext4_free_data+0x15b/0x170 ext4_ind_truncate+0x214/0x2c0 ? _raw_spin_unlock+0x15/0x30 ? ext4_discard_preallocations+0x15a/0x410 ? ext4_journal_check_start+0xe/0x90 ? __ext4_journal_start_sb+0x2f/0x110 ext4_truncate+0x1b5/0x460 ? __ext4_journal_start_sb+0x2f/0x110 ext4_evict_inode+0x2b4/0x6f0 evict+0xd0/0x1d0 ext4_enable_quotas+0x11f/0x1f0 ext4_orphan_cleanup+0x3de/0x430 ? proc_create_seq_private+0x43/0x50 ext4_fill_super+0x295f/0x3ae0 ? snprintf+0x39/0x40 ? sget_fc+0x19c/0x330 ? ext4_reconfigure+0x850/0x850 get_tree_bdev+0x16d/0x260 vfs_get_tree+0x25/0xb0 path_mount+0x431/0xa70 __x64_sys_mount+0xe2/0x120 do_syscall_64+0x5b/0x80 ? do_user_addr_fault+0x1e2/0x670 ? exc_page_fault+0x70/0x170 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fdf4e512ace Fix it by making sure that the block range is properly validated before used every time it changes in ext4_free_blocks() or ext4_mb_clear_bb(). Link: https://syzkaller.appspot.com/bug?id=5266d464285a03cee9dbfda7d2452a72c3c2ae7c Reported-by: syzbot+15cd994e273307bf5cfa@syzkaller.appspotmail.com Signed-off-by: Lukas Czerner Cc: Tadeusz Struk Tested-by: Tadeusz Struk Link: https://lore.kernel.org/r/20220714165903.58260-1-lczerner@redhat.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/mballoc.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 816448041db8..3fc2b8ff2826 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -5916,6 +5916,15 @@ static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode, sbi = EXT4_SB(sb); + if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && + !ext4_inode_block_valid(inode, block, count)) { + ext4_error(sb, "Freeing blocks in system zone - " + "Block = %llu, count = %lu", block, count); + /* err = 0. ext4_std_error should be a no op */ + goto error_return; + } + flags |= EXT4_FREE_BLOCKS_VALIDATED; + do_more: overflow = 0; ext4_get_group_no_and_offset(sb, block, &block_group, &bit); @@ -5932,6 +5941,8 @@ static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode, overflow = EXT4_C2B(sbi, bit) + count - EXT4_BLOCKS_PER_GROUP(sb); count -= overflow; + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; } count_clusters = EXT4_NUM_B2C(sbi, count); bitmap_bh = ext4_read_block_bitmap(sb, block_group); @@ -5946,7 +5957,8 @@ static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode, goto error_return; } - if (!ext4_inode_block_valid(inode, block, count)) { + if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && + !ext4_inode_block_valid(inode, block, count)) { ext4_error(sb, "Freeing blocks in system zone - " "Block = %llu, count = %lu", block, count); /* err = 0. ext4_std_error should be a no op */ @@ -6069,6 +6081,8 @@ static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode, block += count; count = overflow; put_bh(bitmap_bh); + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; goto do_more; } error_return: @@ -6115,6 +6129,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode, "block = %llu, count = %lu", block, count); return; } + flags |= EXT4_FREE_BLOCKS_VALIDATED; ext4_debug("freeing block %llu\n", block); trace_ext4_free_blocks(inode, block, count, flags); @@ -6146,6 +6161,8 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode, block -= overflow; count += overflow; } + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; } overflow = EXT4_LBLK_COFF(sbi, count); if (overflow) { @@ -6156,6 +6173,8 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode, return; } else count += sbi->s_cluster_ratio - overflow; + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; } if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) { -- 2.35.1