This is a note to let you know that I've just added the patch titled
NFSv4: Handle case where the lookup of a directory fails
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsv4-handle-case-where-the-lookup-of-a-directory-fa.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6ad620efd10e1b77690424651775e7c427a20339
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Thu Jan 6 18:24:02 2022 -0500
NFSv4: Handle case where the lookup of a directory fails
[ Upstream commit ac795161c93699d600db16c1a8cc23a65a1eceaf ]
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>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index d405b5a14073a..e7986bc90ea87 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1602,6 +1602,19 @@ 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)
