Implement support for RPCSEC_GSS authentication to both the NFS client

and server. This replaces the RPC implementation of the NFS client and
server with the newer RPC implementation originally developed
(actually ported from the userland sunrpc code) to support the NFS
Lock Manager.  I have tested this code extensively and I believe it is
stable and that performance is at least equal to the legacy RPC
implementation.

The NFS code currently contains support for both the new RPC
implementation and the older legacy implementation inherited from the
original NFS codebase. The default is to use the new implementation -
add the NFS_LEGACYRPC option to fall back to the old code. When I
merge this support back to RELENG_7, I will probably change this so
that users have to 'opt in' to get the new code.

To use RPCSEC_GSS on either client or server, you must build a kernel
which includes the KGSSAPI option and the crypto device. On the
userland side, you must build at least a new libc, mountd, mount_nfs
and gssd. You must install new versions of /etc/rc.d/gssd and
/etc/rc.d/nfsd and add 'gssd_enable=YES' to /etc/rc.conf.

As long as gssd is running, you should be able to mount an NFS
filesystem from a server that requires RPCSEC_GSS authentication. The
mount itself can happen without any kerberos credentials but all
access to the filesystem will be denied unless the accessing user has
a valid ticket file in the standard place (/tmp/krb5cc_<uid>). There
is currently no support for situations where the ticket file is in a
different place, such as when the user logged in via SSH and has
delegated credentials from that login. This restriction is also
present in Solaris and Linux. In theory, we could improve this in
future, possibly using Brooks Davis' implementation of variant
symlinks.

Supporting RPCSEC_GSS on a server is nearly as simple. You must create
service creds for the server in the form 'nfs/<fqdn>@<REALM>' and
install them in /etc/krb5.keytab. The standard heimdal utility ktutil
makes this fairly easy. After the service creds have been created, you
can add a '-sec=krb5' option to /etc/exports and restart both mountd
and nfsd.

The only other difference an administrator should notice is that nfsd
doesn't fork to create service threads any more. In normal operation,
there will be two nfsd processes, one in userland waiting for TCP
connections and one in the kernel handling requests. The latter
process will create as many kthreads as required - these should be
visible via 'top -H'. The code has some support for varying the number
of service threads according to load but initially at least, nfsd uses
a fixed number of threads according to the value supplied to its '-n'
option.

Sponsored by:	Isilon Systems
MFC after:	1 month

1 files changed, 189 insertions, 0 deletions

diff --git a/sys/rpc/rpcsec_gss.h b/sys/rpc/rpcsec_gss.h
new file mode 100644
index 0000000..563205c
--- /dev/null
+++ b/sys/rpc/rpcsec_gss.h
@@ -0,0 +1,189 @@
+/*-
+ * Copyright (c) 2008 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	$FreeBSD$
+ */
+
+#ifndef _RPCSEC_GSS_H
+#define _RPCSEC_GSS_H
+
+#include <kgssapi/gssapi.h>
+
+#ifndef MAX_GSS_MECH
+#define MAX_GSS_MECH	64
+#endif
+
+/*
+ * Define the types of security service required for rpc_gss_seccreate().
+ */
+typedef enum {
+	rpc_gss_svc_default	= 0,
+	rpc_gss_svc_none	= 1,
+	rpc_gss_svc_integrity	= 2,
+	rpc_gss_svc_privacy	= 3
+} rpc_gss_service_t;
+
+/*
+ * Structure containing options for rpc_gss_seccreate().
+ */
+typedef struct {
+	int		req_flags;	/* GSS request bits */
+	int		time_req;	/* requested credential lifetime */
+	gss_cred_id_t	my_cred;	/* GSS credential */
+	gss_channel_bindings_t input_channel_bindings;
+} rpc_gss_options_req_t;
+
+/*
+ * Structure containing options returned by rpc_gss_seccreate().
+ */
+typedef struct {
+	int		major_status;
+	int		minor_status;
+	u_int		rpcsec_version;
+	int		ret_flags;
+	int		time_req;
+	gss_ctx_id_t	gss_context;
+	char		actual_mechanism[MAX_GSS_MECH];
+} rpc_gss_options_ret_t;
+
+/*
+ * Client principal type. Used as an argument to
+ * rpc_gss_get_principal_name(). Also referenced by the
+ * rpc_gss_rawcred_t structure.
+ */
+typedef struct {
+	int		len;
+	char		name[1];
+} *rpc_gss_principal_t;
+
+/*
+ * Structure for raw credentials used by rpc_gss_getcred() and
+ * rpc_gss_set_callback().
+ */
+typedef struct {
+	u_int		version;	/* RPC version number */
+	const char	*mechanism;	/* security mechanism */
+	const char	*qop;		/* quality of protection */
+	rpc_gss_principal_t client_principal; /* client name */
+	const char	*svc_principal;	/* server name */
+	rpc_gss_service_t service;	/* service type */
+} rpc_gss_rawcred_t;
+
+/*
+ * Unix credentials derived from raw credentials. Returned by
+ * rpc_gss_getcred().
+ */
+typedef struct {
+	uid_t		uid;		/* user ID */
+	gid_t		gid;		/* group ID */
+	short		gidlen;
+	gid_t		*gidlist;	/* list of groups */
+} rpc_gss_ucred_t;
+
+/*
+ * Structure used to enforce a particular QOP and service.
+ */
+typedef struct {
+	bool_t		locked;
+	rpc_gss_rawcred_t *raw_cred;
+} rpc_gss_lock_t;
+
+/*
+ * Callback structure used by rpc_gss_set_callback().
+ */
+typedef struct {
+	u_int		program;	/* RPC program number */
+	u_int		version;	/* RPC version number */
+					/* user defined callback */
+	bool_t		(*callback)(struct svc_req *req,
+				    gss_cred_id_t deleg,
+				    gss_ctx_id_t gss_context,
+				    rpc_gss_lock_t *lock,
+				    void **cookie);
+} rpc_gss_callback_t;
+
+/*
+ * Structure used to return error information by rpc_gss_get_error()
+ */
+typedef struct {
+	int		rpc_gss_error;
+	int		system_error;	/* same as errno */
+} rpc_gss_error_t;
+
+/*
+ * Values for rpc_gss_error
+ */
+#define RPC_GSS_ER_SUCCESS	0	/* no error */
+#define RPC_GSS_ER_SYSTEMERROR	1	/* system error */
+
+__BEGIN_DECLS
+
+#ifdef _KERNEL
+AUTH	*rpc_gss_secfind(CLIENT *clnt, struct ucred *cred,
+    const char *principal, gss_OID mech_oid, rpc_gss_service_t service);
+void	rpc_gss_secpurge(CLIENT *clnt);
+#endif
+AUTH	*rpc_gss_seccreate(CLIENT *clnt, struct ucred *cred,
+    const char *principal, const char *mechanism, rpc_gss_service_t service,
+    const char *qop, rpc_gss_options_req_t *options_req,
+    rpc_gss_options_ret_t *options_ret);
+bool_t	rpc_gss_set_defaults(AUTH *auth, rpc_gss_service_t service,
+    const char *qop);
+int	rpc_gss_max_data_length(AUTH *handle, int max_tp_unit_len);
+void	rpc_gss_get_error(rpc_gss_error_t *error);
+
+bool_t	rpc_gss_mech_to_oid(const char *mech, gss_OID *oid_ret);
+bool_t	rpc_gss_oid_to_mech(gss_OID oid, const char **mech_ret);
+bool_t	rpc_gss_qop_to_num(const char *qop, const char *mech, u_int *num_ret);
+const char **rpc_gss_get_mechanisms(void);
+const char **rpc_gss_get_mech_info(const char *mech, rpc_gss_service_t *service);
+bool_t	rpc_gss_get_versions(u_int *vers_hi, u_int *vers_lo);
+bool_t	rpc_gss_is_installed(const char *mech);
+
+bool_t	rpc_gss_set_svc_name(const char *principal, const char *mechanism,
+    u_int req_time, u_int program, u_int version);
+void rpc_gss_clear_svc_name(u_int program, u_int version);
+bool_t	rpc_gss_getcred(struct svc_req *req, rpc_gss_rawcred_t **rcred,
+    rpc_gss_ucred_t **ucred, void **cookie);
+bool_t	rpc_gss_set_callback(rpc_gss_callback_t *cb);
+void rpc_gss_clear_callback(rpc_gss_callback_t *cb);
+bool_t	rpc_gss_get_principal_name(rpc_gss_principal_t *principal,
+    const char *mech, const char *name, const char *node, const char *domain);
+int	rpc_gss_svc_max_data_length(struct svc_req *req, int max_tp_unit_len);
+
+/*
+ * Internal interface from the RPC implementation.
+ */
+#ifndef _KERNEL
+bool_t	__rpc_gss_wrap(AUTH *auth, void *header, size_t headerlen,
+    XDR* xdrs, xdrproc_t xdr_args, void *args_ptr);
+bool_t	__rpc_gss_unwrap(AUTH *auth, XDR* xdrs, xdrproc_t xdr_args,
+    void *args_ptr);
+#endif
+bool_t __rpc_gss_set_error(int rpc_gss_error, int system_error);
+
+__END_DECLS
+
+#endif /* !_RPCSEC_GSS_H */