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From:   Ye Bin <yebin@huaweicloud.com>
To:     tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, jack@suse.cz,
        Ye Bin <yebin10@huawei.com>,
        syzbot+98346927678ac3059c77@syzkaller.appspotmail.com
Subject: [PATCH] ext4: init quota for 'old.inode' in 'ext4_rename'
Date:   Mon,  7 Nov 2022 09:53:35 +0800
Message-Id: <20221107015335.2524319-1-yebin@huaweicloud.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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From: Ye Bin <yebin10@huawei.com>

Syzbot found the following issue:
ext4_parse_param: s_want_extra_isize=128
ext4_inode_info_init: s_want_extra_isize=32
ext4_rename: old.inode=ffff88823869a2c8 old.dir=ffff888238699828 new.inode=ffff88823869d7e8 new.dir=ffff888238699828
__ext4_mark_inode_dirty: inode=ffff888238699828 ea_isize=32 want_ea_size=128
__ext4_mark_inode_dirty: inode=ffff88823869a2c8 ea_isize=32 want_ea_size=128
ext4_xattr_block_set: inode=ffff88823869a2c8
------------[ cut here ]------------
WARNING: CPU: 13 PID: 2234 at fs/ext4/xattr.c:2070 ext4_xattr_block_set.cold+0x22/0x980
Modules linked in:
RIP: 0010:ext4_xattr_block_set.cold+0x22/0x980
RSP: 0018:ffff888227d3f3b0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88823007a000 RCX: 0000000000000000
RDX: 0000000000000a03 RSI: 0000000000000040 RDI: ffff888230078178
RBP: 0000000000000000 R08: 000000000000002c R09: ffffed1075c7df8e
R10: ffff8883ae3efc6b R11: ffffed1075c7df8d R12: 0000000000000000
R13: ffff88823869a2c8 R14: ffff8881012e0460 R15: dffffc0000000000
FS:  00007f350ac1f740(0000) GS:ffff8883ae200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f350a6ed6a0 CR3: 0000000237456000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ? ext4_xattr_set_entry+0x3b7/0x2320
 ? ext4_xattr_block_set+0x0/0x2020
 ? ext4_xattr_set_entry+0x0/0x2320
 ? ext4_xattr_check_entries+0x77/0x310
 ? ext4_xattr_ibody_set+0x23b/0x340
 ext4_xattr_move_to_block+0x594/0x720
 ext4_expand_extra_isize_ea+0x59a/0x10f0
 __ext4_expand_extra_isize+0x278/0x3f0
 __ext4_mark_inode_dirty.cold+0x347/0x410
 ext4_rename+0xed3/0x174f
 vfs_rename+0x13a7/0x2510
 do_renameat2+0x55d/0x920
 __x64_sys_rename+0x7d/0xb0
 do_syscall_64+0x3b/0xa0
 entry_SYSCALL_64_after_hwframe+0x72/0xdc

As 'ext4_rename' will modify 'old.inode' ctime and mark inode dirty, which may
trigger expand 'extra_isize' and allocate block. If inode didn't init quota
will lead to warning.
To solve above issue, init 'old.inode' firstly in 'ext4_rename'.

Reported-by: syzbot+98346927678ac3059c77@syzkaller.appspotmail.com
Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 fs/ext4/namei.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index b8a91d74fdd1..6e40dfc8bd30 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3784,6 +3784,9 @@ static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 		return -EXDEV;
 
 	retval = dquot_initialize(old.dir);
+	if (retval)
+		return retval;
+	retval = dquot_initialize(old.inode);
 	if (retval)
 		return retval;
 	retval = dquot_initialize(new.dir);
-- 
2.31.1