[PATCH 3.16 120/125] nfs: reject changes to resvport and sharecache during remount

Greg Kroah-Hartman
2014-09-03T22:59:26Z

From: Scott Mayhew <smayhew@redhat.com>

commit 71a6ec8ac587418ceb6b420def1ca44b334c1ff7 upstream.

Commit c8e47028 made it possible to change resvport/noresvport and
sharecache/nosharecache via a remount operation, neither of which should be
allowed.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: c8e47028 (nfs: Apply NFS_MOUNT_CMP_FLAGMASK to nfs_compare_remount_data)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/super.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2180,7 +2180,7 @@ out_no_address:
return -EINVAL;
}

-#define NFS_MOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
+#define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
| NFS_MOUNT_SECURE \
| NFS_MOUNT_TCP \
| NFS_MOUNT_VER3 \
@@ -2188,15 +2188,16 @@ out_no_address:
| NFS_MOUNT_NONLM \
| NFS_MOUNT_BROKEN_SUID \
| NFS_MOUNT_STRICTLOCK \
- | NFS_MOUNT_UNSHARED \
- | NFS_MOUNT_NORESVPORT \
| NFS_MOUNT_LEGACY_INTERFACE)

+#define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
+ ~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
+
static int
nfs_compare_remount_data(struct nfs_server *nfss,
struct nfs_parsed_mount_data *data)
{
- if ((data->flags ^ nfss->flags) & NFS_MOUNT_CMP_FLAGMASK ||
+ if ((data->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
data->rsize != nfss->rsize ||
data->wsize != nfss->wsize ||
data->version != nfss->nfs_client->rpc_ops->version ||