With suitably crafted reiserfs image and mount command reiserfs will
crash when trying to verify that XATTR_ROOT directory can be looked up
in / as that recurses back to xattr code like:
xattr_lookup+0x24/0x280 fs/reiserfs/xattr.c:395
reiserfs_xattr_get+0x89/0x540 fs/reiserfs/xattr.c:677
reiserfs_get_acl+0x63/0x690 fs/reiserfs/xattr_acl.c:209
get_acl+0x152/0x2e0 fs/posix_acl.c:141
check_acl fs/namei.c:277 [inline]
acl_permission_check fs/namei.c:309 [inline]
generic_permission+0x2ba/0x550 fs/namei.c:353
do_inode_permission fs/namei.c:398 [inline]
inode_permission+0x234/0x4a0 fs/namei.c:463
lookup_one_len+0xa6/0x200 fs/namei.c:2557
reiserfs_lookup_privroot+0x85/0x1e0 fs/reiserfs/xattr.c:972
reiserfs_fill_super+0x2b51/0x3240 fs/reiserfs/super.c:2176
mount_bdev+0x24f/0x360 fs/super.c:1417
Fix the problem by bailing from reiserfs_xattr_get() when xattrs are not
yet initialized.
CC: stable@xxxxxxxxxxxxxxx
Reported-by: syzbot+9b33c9b118d77ff59b6f@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/reiserfs/xattr.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 28b241cd6987..fe63a7c3e0da 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -674,6 +674,13 @@ reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
if (get_inode_sd_version(inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
+ /*
+ * priv_root needn't be initialized during mount so allow initial
+ * lookups to succeed.
+ */
+ if (!REISERFS_SB(inode->i_sb)->priv_root)
+ return 0;
+
dentry = xattr_lookup(inode, name, XATTR_REPLACE);
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
--
2.16.4
