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@vger.kernel.org Reported-by: syzbot+9b33c9b118d77ff59b6f@syzkaller.appspotmail.com Signed-off-by: Jan Kara jack@suse.cz --- 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);