rpc: allow gss callbacks to client

This patch adds client-side support to allow for callbacks other than
AUTH_SYS.

Signed-off-by: Olga Kornievskaia <aglo@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index c2e9cfd..3e634f2 100644 (file)
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -16,6 +16,7 @@
 #include <linux/mutex.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
+#include <linux/sunrpc/svcauth_gss.h>
 
 #include <net/inet_sock.h>
 
@@ -182,10 +183,34 @@ void nfs_callback_down(void)
        mutex_unlock(&nfs_callback_mutex);
 }
 
+static int check_gss_callback_principal(struct nfs_client *clp,
+                                       struct svc_rqst *rqstp)
+{
+       struct rpc_clnt *r = clp->cl_rpcclient;
+       char *p = svc_gss_principal(rqstp);
+
+       /*
+        * It might just be a normal user principal, in which case
+        * userspace won't bother to tell us the name at all.
+        */
+       if (p == NULL)
+               return SVC_DENIED;
+
+       /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
+
+       if (memcmp(p, "nfs@", 4) != 0)
+               return SVC_DENIED;
+       p += 4;
+       if (strcmp(p, r->cl_server) != 0)
+               return SVC_DENIED;
+       return SVC_OK;
+}
+
 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 {
        struct nfs_client *clp;
        RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
+       int ret = SVC_OK;
 
        /* Don't talk to strangers */
        clp = nfs_find_client(svc_addr(rqstp), 4);
@@ -194,21 +219,22 @@ static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 
        dprintk("%s: %s NFSv4 callback!\n", __func__,
                        svc_print_addr(rqstp, buf, sizeof(buf)));
-       nfs_put_client(clp);
 
        switch (rqstp->rq_authop->flavour) {
                case RPC_AUTH_NULL:
                        if (rqstp->rq_proc != CB_NULL)
-                               return SVC_DENIED;
+                               ret = SVC_DENIED;
                        break;
                case RPC_AUTH_UNIX:
                        break;
                case RPC_AUTH_GSS:
-                       /* FIXME: RPCSEC_GSS handling? */
+                       ret = check_gss_callback_principal(clp, rqstp);
+                       break;
                default:
-                       return SVC_DENIED;
+                       ret = SVC_DENIED;
        }
-       return SVC_OK;
+       nfs_put_client(clp);
+       return ret;
 }
 
 /*

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index e9baa6e..2278a50 100644 (file)
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -935,6 +935,7 @@ char *svc_gss_principal(struct svc_rqst *rqstp)
                return gd->rsci->client_name;
        return NULL;
 }
+EXPORT_SYMBOL_GPL(svc_gss_principal);
 
 static int
 svcauth_gss_set_client(struct svc_rqst *rqstp)