2024-05-28 23:12:02

by NeilBrown

Subject: [PATCH] NFS: abort nfs_atomic_open_v23 if name is too long.

An attempt to open a file with a name longer than NFS3_MAXNAMLEN will
trigger a WARN_ON_ONCE in encode_filename3() because
nfs_atomic_open_v23() doesn't have the test on ->d_name.len that
nfs_atomic_open() has.

So add that test.

Reported-by: James Clark <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Fixes: 7c6c5249f061 ("NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.")
Signed-off-by: NeilBrown <[email protected]>
---
fs/nfs/dir.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 342930996226..2b09b5416ef1 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2255,6 +2255,9 @@ int nfs_atomic_open_v23(struct inode *dir, struct dentry *dentry,
*/
int error = 0;

+ if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
+ return -ENAMETOOLONG;
+
if (open_flags & O_CREAT) {
file->f_mode |= FMODE_CREATED;
error = nfs_do_create(dir, dentry, mode, open_flags);
--
2.44.0

2024-05-29 06:25:33

by Christoph Hellwig

Subject: Re: [PATCH] NFS: abort nfs_atomic_open_v23 if name is too long.

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>