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| author | zhangyi (F) <yi.zhang@huawei.com> | 2021-03-05 20:05:08 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2021-03-21 00:09:17 -0400 |
| commit | 6b22489911b726eebbf169caee52fea52013fbdd (patch) | |
| tree | 244fdd3d130ae305d1f672faa18b919f3905a71f | |
| parent | 5dccdc5a1916d4266edd251f20bbbb113a5c495f (diff) | |
| download | linux-stericsson-6b22489911b726eebbf169caee52fea52013fbdd.tar.gz | |
ext4: do not try to set xattr into ea_inode if value is empty
Syzbot report a warning that ext4 may create an empty ea_inode if set
an empty extent attribute to a file on the file system which is no free
blocks left.
WARNING: CPU: 6 PID: 10667 at fs/ext4/xattr.c:1640 ext4_xattr_set_entry+0x10f8/0x1114 fs/ext4/xattr.c:1640
...
Call trace:
ext4_xattr_set_entry+0x10f8/0x1114 fs/ext4/xattr.c:1640
ext4_xattr_block_set+0x1d0/0x1b1c fs/ext4/xattr.c:1942
ext4_xattr_set_handle+0x8a0/0xf1c fs/ext4/xattr.c:2390
ext4_xattr_set+0x120/0x1f0 fs/ext4/xattr.c:2491
ext4_xattr_trusted_set+0x48/0x5c fs/ext4/xattr_trusted.c:37
__vfs_setxattr+0x208/0x23c fs/xattr.c:177
...
Now, ext4 try to store extent attribute into an external inode if
ext4_xattr_block_set() return -ENOSPC, but for the case of store an
empty extent attribute, store the extent entry into the extent
attribute block is enough. A simple reproduce below.
fallocate test.img -l 1M
mkfs.ext4 -F -b 2048 -O ea_inode test.img
mount test.img /mnt
dd if=/dev/zero of=/mnt/foo bs=2048 count=500
setfattr -n "user.test" /mnt/foo
Reported-by: syzbot+98b881fdd8ebf45ab4ae@syzkaller.appspotmail.com
Fixes: 9c6e7853c531 ("ext4: reserve space for xattr entries/names")
Cc: stable@kernel.org
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210305120508.298465-1-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/xattr.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 083c95126781db..6c1018223c54af 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -2404,7 +2404,7 @@ retry_inode: * external inode if possible. */ if (ext4_has_feature_ea_inode(inode->i_sb) && - !i.in_inode) { + i.value_len && !i.in_inode) { i.in_inode = 1; goto retry_inode; } |