NFS: Determine initial mount security

When sec=<something> is not presented as a mount option,
we should attempt to determine what security flavor the
server is using.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 31 insertions, 2 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 563463777d9d..f9150f03d640 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -41,6 +41,7 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/gss_api.h>
 #include <linux/nfs.h>
 #include <linux/nfs4.h>
 #include <linux/nfs_fs.h>
@@ -2191,15 +2192,43 @@ static int nfs4_lookup_root(struct nfs_server *server, struct nfs_fh *fhandle,
         return err;
 }
 
+static int nfs4_lookup_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
+                                struct nfs_fsinfo *info, rpc_authflavor_t flavor)
+{
+        struct rpc_auth *auth;
+        int ret;
+
+        auth = rpcauth_create(flavor, server->client);
+        if (!auth) {
+                ret = -EIO;
+                goto out;
+        }
+        ret = nfs4_lookup_root(server, fhandle, info);
+        if (ret < 0)
+                ret = -EAGAIN;
+out:
+        return ret;
+}
+
 /*
  * get the file handle for the "/" directory on the server
  */
 static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
                               struct nfs_fsinfo *info)
 {
-        int status;
+        int i, len, status = 0;
+        rpc_authflavor_t flav_array[NFS_MAX_SECFLAVORS + 2];
 
-        status = nfs4_lookup_root(server, fhandle, info);
+        flav_array[0] = RPC_AUTH_UNIX;
+        len = gss_mech_list_pseudoflavors(&flav_array[1]);
+        flav_array[1+len] = RPC_AUTH_NULL;
+        len += 2;
+
+        for (i = 0; i < len; i++) {
+                status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
+                if (status == 0)
+                        break;
+        }
         if (status == 0)
                 status = nfs4_server_capabilities(server, fhandle);
         if (status == 0)