[PATCH 4.19 27/36] nfsd: apply umask on fs without ACL support

Greg Kroah-Hartman
2020-07-07T15:19:36Z

From: J. Bruce Fields <bfields@redhat.com>

commit 22cf8419f1319ff87ec759d0ebdff4cbafaee832 upstream.

The server is failing to apply the umask when creating new objects on
filesystems without ACL support.

To reproduce this, you need to use NFSv4.2 and a client and server
recent enough to support umask, and you need to export a filesystem that
lacks ACL support (for example, ext4 with the "noacl" mount option).

Filesystems with ACL support are expected to take care of the umask
themselves (usually by calling posix_acl_create).

For filesystems without ACL support, this is up to the caller of
vfs_create(), vfs_mknod(), or vfs_mkdir().

Reported-by: Elliott Mitchell <ehem+debian@m5p.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Fixes: 47057abde515 ("nfsd: add support for the umask attribute")
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfsd/vfs.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1206,6 +1206,9 @@ nfsd_create_locked(struct svc_rqst *rqst
iap->ia_mode = 0;
iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;

+ if (!IS_POSIXACL(dirp))
+ iap->ia_mode &= ~current_umask();
+
err = 0;
host_err = 0;
switch (type) {
@@ -1439,6 +1442,9 @@ do_nfsd_create(struct svc_rqst *rqstp, s
goto out;
}

+ if (!IS_POSIXACL(dirp))
+ iap->ia_mode &= ~current_umask();
+
host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
if (host_err < 0) {
fh_drop_write(fhp);