The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From ac795161c93699d600db16c1a8cc23a65a1eceaf Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Thu, 6 Jan 2022 18:24:02 -0500
Subject: [PATCH] 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@xxxxxxx>
Fixes: 0dd2b474d0b6 ("nfs: implement i_op->atomic_open()")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 2884138848f4..408c3bb549b1 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -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)
