SUNRPC: Add RPC based upcall mechanism for RPCGSS auth

This patch implements a sunrpc client to use the services of the gssproxy
userspace daemon.

In particular it allows to perform calls in user space using an RPC
call instead of custom hand-coded upcall/downcall messages.

Currently only accept_sec_context is implemented as that is all is needed for
the server case.

File server modules like NFS and CIFS can use full gssapi services this way,
once init_sec_context is also implemented.

For the NFS server case this code allow to lift the limit of max 2k krb5
tickets. This limit is prevents legitimate kerberos deployments from using krb5
authentication with the Linux NFS server as they have normally ticket that are
many kilobytes large.

It will also allow to lift the limitation on the size of the credential set
(uid,gid,gids) passed down from user space for users that have very many groups
associated. Currently the downcall mechanism used by rpc.svcgssd is limited
to around 2k secondary groups of the 65k allowed by kernel structures.

Signed-off-by: Simo Sorce <simo@redhat.com>
[bfields: containerization, concurrent upcalls, misc. fixes and cleanup]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/net/sunrpc/auth_gss/gss_rpc_upcall.h b/net/sunrpc/auth_gss/gss_rpc_upcall.h
new file mode 100644
index 000000000000..4c2caaa7e84e
--- /dev/null
+++ b/net/sunrpc/auth_gss/gss_rpc_upcall.h
@@ -0,0 +1,47 @@
+/*
+ *  linux/net/sunrpc/gss_rpc_upcall.h
+ *
+ *  Copyright (C) 2012 Simo Sorce <simo@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _GSS_RPC_UPCALL_H
+#define _GSS_RPC_UPCALL_H
+
+#include <linux/sunrpc/auth_gss.h>
+#include "gss_rpc_xdr.h"
+#include "../netns.h"
+
+struct gssp_upcall_data {
+	struct xdr_netobj in_handle;
+	struct gssp_in_token in_token;
+	struct xdr_netobj out_handle;
+	struct xdr_netobj out_token;
+	struct xdr_netobj mech_oid;
+	struct svc_cred creds;
+	int found_creds;
+	int major_status;
+	int minor_status;
+};
+
+int gssp_accept_sec_context_upcall(struct net *net,
+				struct gssp_upcall_data *data);
+void gssp_free_upcall_data(struct gssp_upcall_data *data);
+
+void init_gssp_clnt(struct sunrpc_net *);
+int set_gssp_clnt(struct net *);
+void clear_gssp_clnt(struct sunrpc_net *);
+#endif /* _GSS_RPC_UPCALL_H */