NFSv4: Handle case where the lookup of a directory fails

If the application sets the O_DIRECTORY flag, and tries to open a
regular file, nfs_atomic_open() will punt to doing a regular lookup.
If the server then returns a regular file, we will happily return a
file descriptor with uninitialised open state.

The fix is to return the expected ENOTDIR error in these cases.

Reported-by: Lyu Tao <tao.lyu@epfl.ch>
Fixes: 0dd2b474d0 ("nfs: implement i_op->atomic_open()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Trond Myklebust 2022-01-06 18:24:02 -05:00 committed by Anna Schumaker
parent 34bf20ce98
commit ac795161c9

View file

@ -1994,6 +1994,19 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
no_open:
res = nfs_lookup(dir, dentry, lookup_flags);
if (!res) {
inode = d_inode(dentry);
if ((lookup_flags & LOOKUP_DIRECTORY) && inode &&
!S_ISDIR(inode->i_mode))
res = ERR_PTR(-ENOTDIR);
} else if (!IS_ERR(res)) {
inode = d_inode(res);
if ((lookup_flags & LOOKUP_DIRECTORY) && inode &&
!S_ISDIR(inode->i_mode)) {
dput(res);
res = ERR_PTR(-ENOTDIR);
}
}
if (switched) {
d_lookup_done(dentry);
if (!res)