SUNRPC: Clean up the RPCSEC_GSS service ticket requests

Instead of hacking specific service names into gss_encode_v1_msg, we should
just allow the caller to specify the service name explicitly.

Signed-off-by: Trond Myklebust <[e-mail]>
Acked-by: J. Bruce Fields <[e-mail]>

fs/nfs/client.c

···
 	clp->cl_minorversion = cl_init->minorversion;
 	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
 #endif
-	cred = rpc_lookup_machine_cred();
+	cred = rpc_lookup_machine_cred("*");
 	if (!IS_ERR(cred))
 		clp->cl_machine_cred = cred;
 	nfs_fscache_get_client_cookie(clp);

fs/nfsd/nfs4callback.c

···
 {
 	if (callback_cred)
 		return 0;
-	callback_cred = rpc_lookup_machine_cred();
+	callback_cred = rpc_lookup_machine_cred("nfs");
 	if (!callback_cred)
 		return -ENOMEM;
 	return 0;

include/linux/sunrpc/auth.h

···
 	uid_t	uid;
 	gid_t	gid;
 	struct group_info *group_info;
+	const char *principal;
 	unsigned char machine_cred : 1;
 };
 
···
 void 			rpc_destroy_authunix(void);
 
 struct rpc_cred *	rpc_lookup_cred(void);
-struct rpc_cred *	rpc_lookup_machine_cred(void);
+struct rpc_cred *	rpc_lookup_machine_cred(const char *service_name);
 int			rpcauth_register(const struct rpc_authops *);
 int			rpcauth_unregister(const struct rpc_authops *);
 struct rpc_auth *	rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);

include/linux/sunrpc/auth_gss.h

···
 	enum rpc_gss_svc	gc_service;
 	struct gss_cl_ctx __rcu	*gc_ctx;
 	struct gss_upcall_msg	*gc_upcall;
+	const char		*gc_principal;
 	unsigned long		gc_upcall_timestamp;
-	unsigned char		gc_machine_cred : 1;
 };
 
 #endif /* __KERNEL__ */

net/sunrpc/auth_generic.c

···
 /*
  * Public call interface for looking up machine creds.
  */
-struct rpc_cred *rpc_lookup_machine_cred(void)
+struct rpc_cred *rpc_lookup_machine_cred(const char *service_name)
 {
 	struct auth_cred acred = {
 		.uid = RPC_MACHINE_CRED_USERID,
 		.gid = RPC_MACHINE_CRED_GROUPID,
+		.principal = service_name,
 		.machine_cred = 1,
 	};
 
-	dprintk("RPC:       looking up machine cred\n");
+	dprintk("RPC:       looking up machine cred for service %s\n",
+			service_name);
 	return generic_auth.au_ops->lookup_cred(&generic_auth, &acred, 0);
 }
 EXPORT_SYMBOL_GPL(rpc_lookup_machine_cred);

net/sunrpc/auth_gss/auth_gss.c

···
 }
 
 static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
-				struct rpc_clnt *clnt, int machine_cred)
+				struct rpc_clnt *clnt,
+				const char *service_name)
 {
 	struct gss_api_mech *mech = gss_msg->auth->mech;
 	char *p = gss_msg->databuf;
···
 		p += len;
 		gss_msg->msg.len += len;
 	}
-	if (machine_cred) {
-		len = sprintf(p, "service=* ");
-		p += len;
-		gss_msg->msg.len += len;
-	} else if (!strcmp(clnt->cl_program->name, "nfs4_cb")) {
-		len = sprintf(p, "service=nfs ");
+	if (service_name != NULL) {
+		len = sprintf(p, "service=%s ", service_name);
 		p += len;
 		gss_msg->msg.len += len;
 	}
···
 }
 
 static void gss_encode_msg(struct gss_upcall_msg *gss_msg,
-				struct rpc_clnt *clnt, int machine_cred)
+				struct rpc_clnt *clnt,
+				const char *service_name)
 {
 	if (pipe_version == 0)
 		gss_encode_v0_msg(gss_msg);
 	else /* pipe_version == 1 */
-		gss_encode_v1_msg(gss_msg, clnt, machine_cred);
+		gss_encode_v1_msg(gss_msg, clnt, service_name);
 }
 
-static inline struct gss_upcall_msg *
-gss_alloc_msg(struct gss_auth *gss_auth, uid_t uid, struct rpc_clnt *clnt,
-		int machine_cred)
+static struct gss_upcall_msg *
+gss_alloc_msg(struct gss_auth *gss_auth, struct rpc_clnt *clnt,
+		uid_t uid, const char *service_name)
 {
 	struct gss_upcall_msg *gss_msg;
 	int vers;
···
 	atomic_set(&gss_msg->count, 1);
 	gss_msg->uid = uid;
 	gss_msg->auth = gss_auth;
-	gss_encode_msg(gss_msg, clnt, machine_cred);
+	gss_encode_msg(gss_msg, clnt, service_name);
 	return gss_msg;
 }
 
···
 	struct gss_upcall_msg *gss_new, *gss_msg;
 	uid_t uid = cred->cr_uid;
 
-	gss_new = gss_alloc_msg(gss_auth, uid, clnt, gss_cred->gc_machine_cred);
+	gss_new = gss_alloc_msg(gss_auth, clnt, uid, gss_cred->gc_principal);
 	if (IS_ERR(gss_new))
 		return gss_new;
 	gss_msg = gss_add_msg(gss_new);
···
 	 */
 	cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
 	cred->gc_service = gss_auth->service;
-	cred->gc_machine_cred = acred->machine_cred;
+	cred->gc_principal = NULL;
+	if (acred->machine_cred)
+		cred->gc_principal = acred->principal;
 	kref_get(&gss_auth->kref);
 	return &cred->gc_base;
 
···
 	if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
 		return 0;
 out:
-	if (acred->machine_cred != gss_cred->gc_machine_cred)
+	if (acred->principal != NULL) {
+		if (gss_cred->gc_principal == NULL)
+			return 0;
+		return strcmp(acred->principal, gss_cred->gc_principal) == 0;
+	}
+	if (gss_cred->gc_principal != NULL)
 		return 0;
 	return rc->cr_uid == acred->uid;
 }
···
 	struct rpc_auth *auth = oldcred->cr_auth;
 	struct auth_cred acred = {
 		.uid = oldcred->cr_uid,
-		.machine_cred = gss_cred->gc_machine_cred,
+		.principal = gss_cred->gc_principal,
+		.machine_cred = (gss_cred->gc_principal != NULL ? 1 : 0),
 	};
 	struct rpc_cred *new;