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authorzhangyi (F) <yi.zhang@huawei.com>2021-03-05 20:05:08 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-03-24 11:26:44 +0100
commit2f65ae3a7ee3b9f47f6d205c6d04887101103248 (patch)
tree346daa142817b83bb24da1784edcce9bd7755521
parent474aab4484369866b7247ba1bba3cb99323d0dc0 (diff)
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ext4: do not try to set xattr into ea_inode if value is empty
commit 6b22489911b726eebbf169caee52fea52013fbdd upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/xattr.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 894a61010ae9..5451f1080006 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2415,7 +2415,7 @@ 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;
}