Add an implementation of the RPCSEC_GSS authentication protocol for RPC. This

is based on an old implementation from the University of Michigan with lots of
changes and fixes by me and the addition of a Solaris-compatible API.

Sponsored by:	Isilon Systems
Reviewed by:	alfred

1 files changed, 1214 insertions, 0 deletions

diff --git a/lib/librpcsec_gss/svc_rpcsec_gss.c b/lib/librpcsec_gss/svc_rpcsec_gss.c
new file mode 100644
index 0000000..7eff62a
--- /dev/null
+++ b/lib/librpcsec_gss/svc_rpcsec_gss.c
@@ -0,0 +1,1214 @@
+/*-
+ * 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.
+ *
+ *	$FreeBSD$
+ */
+/*
+  svc_rpcsec_gss.c
+  
+  Copyright (c) 2000 The Regents of the University of Michigan.
+  All rights reserved.
+
+  Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>.
+  All rights reserved, all wrongs reversed.
+
+  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.
+  3. Neither the name of the University nor the names of its
+     contributors may be used to endorse or promote products derived
+     from this software without specific prior written permission.
+
+  THIS SOFTWARE IS PROVIDED ``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 REGENTS 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.
+
+  $Id: svc_auth_gss.c,v 1.27 2002/01/15 15:43:00 andros Exp $
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pwd.h>
+#include <grp.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/queue.h>
+#include <rpc/rpc.h>
+#include <rpc/rpcsec_gss.h>
+#include "rpcsec_gss_int.h"
+
+static bool_t	svc_rpc_gss_initialised = FALSE;
+
+static bool_t   svc_rpc_gss_wrap(SVCAUTH *, XDR *, xdrproc_t, caddr_t);
+static bool_t   svc_rpc_gss_unwrap(SVCAUTH *, XDR *, xdrproc_t, caddr_t);
+static enum auth_stat svc_rpc_gss(struct svc_req *, struct rpc_msg *);
+
+static struct svc_auth_ops svc_auth_gss_ops = {
+	svc_rpc_gss_wrap,
+	svc_rpc_gss_unwrap,
+};
+
+struct svc_rpc_gss_callback {
+	SLIST_ENTRY(svc_rpc_gss_callback) cb_link;
+	rpc_gss_callback_t	cb_callback;
+};
+static SLIST_HEAD(svc_rpc_gss_callback_list, svc_rpc_gss_callback)
+	svc_rpc_gss_callbacks = SLIST_HEAD_INITIALIZER(&svc_rpc_gss_callbacks);
+
+struct svc_rpc_gss_svc_name {
+	SLIST_ENTRY(svc_rpc_gss_svc_name) sn_link;
+	char			*sn_principal;
+	gss_OID			sn_mech;
+	u_int			sn_req_time;
+	gss_cred_id_t		sn_cred;
+	u_int			sn_program;
+	u_int			sn_version;
+};
+static SLIST_HEAD(svc_rpc_gss_svc_name_list, svc_rpc_gss_svc_name)
+	svc_rpc_gss_svc_names = SLIST_HEAD_INITIALIZER(&svc_rpc_gss_svc_names);
+
+enum svc_rpc_gss_client_state {
+	CLIENT_NEW,				/* still authenticating */
+	CLIENT_ESTABLISHED,			/* context established */
+	CLIENT_STALE				/* garbage to collect */
+};
+
+#define SVC_RPC_GSS_SEQWINDOW	128
+
+struct svc_rpc_gss_client {
+	TAILQ_ENTRY(svc_rpc_gss_client) cl_link;
+	TAILQ_ENTRY(svc_rpc_gss_client) cl_alllink;
+	uint32_t		cl_id;
+	time_t			cl_expiration;	/* when to gc */
+	enum svc_rpc_gss_client_state cl_state;	/* client state */
+	bool_t			cl_locked;	/* fixed service+qop */
+	gss_ctx_id_t		cl_ctx;		/* context id */
+	gss_cred_id_t		cl_creds;	/* delegated creds */
+	gss_name_t		cl_cname;	/* client name */
+	struct svc_rpc_gss_svc_name *cl_sname;	/* server name used */
+	rpc_gss_rawcred_t	cl_rawcred;	/* raw credentials */
+	rpc_gss_ucred_t		cl_ucred;	/* unix-style credentials */
+	bool_t			cl_done_callback; /* TRUE after call */
+	void			*cl_cookie;	/* user cookie from callback */
+	gid_t			cl_gid_storage[NGRPS];
+	gss_OID			cl_mech;	/* mechanism */
+	gss_qop_t		cl_qop;		/* quality of protection */
+	u_int			cl_seq;		/* current sequence number */
+	u_int			cl_win;		/* sequence window size */
+	u_int			cl_seqlast;	/* sequence window origin */
+	uint32_t		cl_seqmask[SVC_RPC_GSS_SEQWINDOW/32]; /* bitmask of seqnums */
+	gss_buffer_desc		cl_verf;	/* buffer for verf checksum */
+};
+TAILQ_HEAD(svc_rpc_gss_client_list, svc_rpc_gss_client);
+
+#define CLIENT_HASH_SIZE	256
+#define CLIENT_MAX		128
+struct svc_rpc_gss_client_list svc_rpc_gss_client_hash[CLIENT_HASH_SIZE];
+struct svc_rpc_gss_client_list svc_rpc_gss_clients;
+static size_t svc_rpc_gss_client_count;
+static uint32_t svc_rpc_gss_next_clientid = 1;
+
+#ifdef __GNUC__
+static void svc_rpc_gss_init(void) __attribute__ ((constructor));
+#endif
+
+static void
+svc_rpc_gss_init(void)
+{
+	int i;
+
+	if (!svc_rpc_gss_initialised) {
+		for (i = 0; i < CLIENT_HASH_SIZE; i++)
+			TAILQ_INIT(&svc_rpc_gss_client_hash[i]);
+		TAILQ_INIT(&svc_rpc_gss_clients);
+		svc_auth_reg(RPCSEC_GSS, svc_rpc_gss);
+		svc_rpc_gss_initialised = TRUE;
+	}
+}
+
+bool_t
+rpc_gss_set_callback(rpc_gss_callback_t *cb)
+{
+	struct svc_rpc_gss_callback *scb;
+
+	scb = malloc(sizeof(struct svc_rpc_gss_callback));
+	if (!scb) {
+		_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
+		return (FALSE);
+	}
+	scb->cb_callback = *cb;
+	SLIST_INSERT_HEAD(&svc_rpc_gss_callbacks, scb, cb_link);
+
+	return (TRUE);
+}
+
+bool_t
+rpc_gss_set_svc_name(const char *principal, const char *mechanism,
+    u_int req_time, u_int program, u_int version)
+{
+	OM_uint32		maj_stat, min_stat;
+	struct svc_rpc_gss_svc_name *sname;
+	gss_buffer_desc		namebuf;
+	gss_name_t		name;
+	gss_OID			mech_oid;
+	gss_OID_set_desc	oid_set;
+	gss_cred_id_t		cred;
+
+	svc_rpc_gss_init();
+
+	if (!rpc_gss_mech_to_oid(mechanism, &mech_oid))
+		return (FALSE);
+	oid_set.count = 1;
+	oid_set.elements = mech_oid;
+
+	namebuf.value = (void *)(intptr_t) principal;
+	namebuf.length = strlen(principal);
+
+	maj_stat = gss_import_name(&min_stat, &namebuf,
+				   GSS_C_NT_HOSTBASED_SERVICE, &name);
+	if (maj_stat != GSS_S_COMPLETE)
+		return (FALSE);
+
+	maj_stat = gss_acquire_cred(&min_stat, name,
+	    req_time, &oid_set, GSS_C_ACCEPT, &cred, NULL, NULL);
+	if (maj_stat != GSS_S_COMPLETE)
+		return (FALSE);
+
+	gss_release_name(&min_stat, &name);
+
+	sname = malloc(sizeof(struct svc_rpc_gss_svc_name));
+	if (!sname)
+		return (FALSE);
+	sname->sn_principal = strdup(principal);
+	sname->sn_mech = mech_oid;
+	sname->sn_req_time = req_time;
+	sname->sn_cred = cred;
+	sname->sn_program = program;
+	sname->sn_version = version;
+	SLIST_INSERT_HEAD(&svc_rpc_gss_svc_names, sname, sn_link);
+
+	return (TRUE);
+}
+
+bool_t
+rpc_gss_get_principal_name(rpc_gss_principal_t *principal,
+    const char *mech, const char *name, const char *node, const char *domain)
+{
+	OM_uint32		maj_stat, min_stat;
+	gss_OID			mech_oid;
+	size_t			namelen;
+	gss_buffer_desc		buf;
+	gss_name_t		gss_name, gss_mech_name;
+	rpc_gss_principal_t	result;
+
+	svc_rpc_gss_init();
+
+	if (!rpc_gss_mech_to_oid(mech, &mech_oid))
+		return (FALSE);
+
+	/*
+	 * Construct a gss_buffer containing the full name formatted
+	 * as "name/node@domain" where node and domain are optional.
+	 */
+	namelen = strlen(name);
+	if (node) {
+		namelen += strlen(node) + 1;
+	}
+	if (domain) {
+		namelen += strlen(domain) + 1;
+	}
+
+	buf.value = malloc(namelen);
+	buf.length = namelen;
+	strcpy((char *) buf.value, name);
+	if (node) {
+		strcat((char *) buf.value, "/");
+		strcat((char *) buf.value, node);
+	}
+	if (domain) {
+		strcat((char *) buf.value, "@");
+		strcat((char *) buf.value, domain);
+	}
+
+	/*
+	 * Convert that to a gss_name_t and then convert that to a
+	 * mechanism name in the selected mechanism.
+	 */
+	maj_stat = gss_import_name(&min_stat, &buf,
+	    GSS_C_NT_USER_NAME, &gss_name);
+	free(buf.value);
+	if (maj_stat != GSS_S_COMPLETE) {
+		log_status("gss_import_name", mech_oid, maj_stat, min_stat);
+		return (FALSE);
+	}
+	maj_stat = gss_canonicalize_name(&min_stat, gss_name, mech_oid,
+	    &gss_mech_name);
+	if (maj_stat != GSS_S_COMPLETE) {
+		log_status("gss_canonicalize_name", mech_oid, maj_stat,
+		    min_stat);
+		gss_release_name(&min_stat, &gss_name);
+		return (FALSE);
+	}
+	gss_release_name(&min_stat, &gss_name);
+
+	/*
+	 * Export the mechanism name and use that to construct the
+	 * rpc_gss_principal_t result.
+	 */
+	maj_stat = gss_export_name(&min_stat, gss_mech_name, &buf);
+	if (maj_stat != GSS_S_COMPLETE) {
+		log_status("gss_export_name", mech_oid, maj_stat, min_stat);
+		gss_release_name(&min_stat, &gss_mech_name);
+		return (FALSE);
+	}
+	gss_release_name(&min_stat, &gss_mech_name);
+
+	result = malloc(sizeof(int) + buf.length);
+	if (!result) {
+		gss_release_buffer(&min_stat, &buf);
+		return (FALSE);
+	}
+	result->len = buf.length;
+	memcpy(result->name, buf.value, buf.length);
+	gss_release_buffer(&min_stat, &buf);
+
+	*principal = result;
+	return (TRUE);
+}
+
+bool_t
+rpc_gss_getcred(struct svc_req *req, rpc_gss_rawcred_t **rcred,
+    rpc_gss_ucred_t **ucred, void **cookie)
+{
+	struct svc_rpc_gss_client *client;
+
+	if (req->rq_cred.oa_flavor != RPCSEC_GSS)
+		return (FALSE);
+
+	client = req->rq_clntcred;
+	if (rcred)
+		*rcred = &client->cl_rawcred;
+	if (ucred)
+		*ucred = &client->cl_ucred;
+	if (cookie)
+		*cookie = client->cl_cookie;
+	return (TRUE);
+}
+
+int
+rpc_gss_svc_max_data_length(struct svc_req *req, int max_tp_unit_len)
+{
+	struct svc_rpc_gss_client *client = req->rq_clntcred;
+	int			want_conf;
+	OM_uint32		max;
+	OM_uint32		maj_stat, min_stat;
+	int			result;
+
+	switch (client->cl_rawcred.service) {
+	case rpc_gss_svc_none:
+		return (max_tp_unit_len);
+		break;
+
+	case rpc_gss_svc_default:
+	case rpc_gss_svc_integrity:
+		want_conf = FALSE;
+		break;
+
+	case rpc_gss_svc_privacy:
+		want_conf = TRUE;
+		break;
+
+	default:
+		return (0);
+	}
+
+	maj_stat = gss_wrap_size_limit(&min_stat, client->cl_ctx, want_conf,
+	    client->cl_qop, max_tp_unit_len, &max);
+
+	if (maj_stat == GSS_S_COMPLETE) {
+		result = (int) max;
+		if (result < 0)
+			result = 0;
+		return (result);
+	} else {
+		log_status("gss_wrap_size_limit", client->cl_mech,
+		    maj_stat, min_stat);
+		return (0);
+	}
+}
+
+static struct svc_rpc_gss_client *
+svc_rpc_gss_find_client(uint32_t clientid)
+{
+	struct svc_rpc_gss_client *client;
+	struct svc_rpc_gss_client_list *list;
+
+
+	log_debug("in svc_rpc_gss_find_client(%d)", clientid);
+
+	list = &svc_rpc_gss_client_hash[clientid % CLIENT_HASH_SIZE];
+	TAILQ_FOREACH(client, list, cl_link) {
+		if (client->cl_id == clientid) {
+			/*
+			 * Move this client to the front of the LRU
+			 * list.
+			 */
+			TAILQ_REMOVE(&svc_rpc_gss_clients, client, cl_alllink);
+			TAILQ_INSERT_HEAD(&svc_rpc_gss_clients, client,
+			    cl_alllink);
+			return client;
+		}
+	}
+
+	return (NULL);
+}
+
+static struct svc_rpc_gss_client *
+svc_rpc_gss_create_client(void)
+{
+	struct svc_rpc_gss_client *client;
+	struct svc_rpc_gss_client_list *list;
+
+	log_debug("in svc_rpc_gss_create_client()");
+
+	client = mem_alloc(sizeof(struct svc_rpc_gss_client));
+	memset(client, 0, sizeof(struct svc_rpc_gss_client));
+	client->cl_id = svc_rpc_gss_next_clientid++;
+	list = &svc_rpc_gss_client_hash[client->cl_id % CLIENT_HASH_SIZE];
+	TAILQ_INSERT_HEAD(list, client, cl_link);
+	TAILQ_INSERT_HEAD(&svc_rpc_gss_clients, client, cl_alllink);
+
+	/*
+	 * Start the client off with a short expiration time. We will
+	 * try to get a saner value from the client creds later.
+	 */
+	client->cl_state = CLIENT_NEW;
+	client->cl_locked = FALSE;
+	client->cl_expiration = time(0) + 5*60;
+	svc_rpc_gss_client_count++;
+
+	return (client);
+}
+
+static void
+svc_rpc_gss_destroy_client(struct svc_rpc_gss_client *client)
+{
+	struct svc_rpc_gss_client_list *list;
+	OM_uint32 min_stat;
+
+	log_debug("in svc_rpc_gss_destroy_client()");
+
+	if (client->cl_ctx)
+		gss_delete_sec_context(&min_stat,
+		    &client->cl_ctx, GSS_C_NO_BUFFER);
+
+	if (client->cl_cname)
+		gss_release_name(&min_stat, &client->cl_cname);
+
+	if (client->cl_rawcred.client_principal)
+		free(client->cl_rawcred.client_principal);
+
+	if (client->cl_verf.value)
+		gss_release_buffer(&min_stat, &client->cl_verf);
+
+	list = &svc_rpc_gss_client_hash[client->cl_id % CLIENT_HASH_SIZE];
+	TAILQ_REMOVE(list, client, cl_link);
+	TAILQ_REMOVE(&svc_rpc_gss_clients, client, cl_alllink);
+	svc_rpc_gss_client_count--;
+	mem_free(client, sizeof(*client));
+}
+
+static void
+svc_rpc_gss_timeout_clients(void)
+{
+	struct svc_rpc_gss_client *client;
+	struct svc_rpc_gss_client *nclient;
+	time_t now = time(0);
+
+	log_debug("in svc_rpc_gss_timeout_clients()");
+	/*
+	 * First enforce the max client limit. We keep
+	 * svc_rpc_gss_clients in LRU order.
+	 */
+	while (svc_rpc_gss_client_count > CLIENT_MAX)
+		svc_rpc_gss_destroy_client(TAILQ_LAST(&svc_rpc_gss_clients,
+			    svc_rpc_gss_client_list));
+	TAILQ_FOREACH_SAFE(client, &svc_rpc_gss_clients, cl_alllink, nclient) {
+		if (client->cl_state == CLIENT_STALE
+		    || now > client->cl_expiration) {
+			log_debug("expiring client %p", client);
+			svc_rpc_gss_destroy_client(client);
+		}
+	}
+}
+
+#ifdef DEBUG
+/*
+ * OID<->string routines.  These are uuuuugly.
+ */
+static OM_uint32
+gss_oid_to_str(OM_uint32 *minor_status, gss_OID oid, gss_buffer_t oid_str)
+{
+	char		numstr[128];
+	unsigned long	number;
+	int		numshift;
+	size_t		string_length;
+	size_t		i;
+	unsigned char	*cp;
+	char		*bp;
+
+	/* Decoded according to krb5/gssapi_krb5.c */
+
+	/* First determine the size of the string */
+	string_length = 0;
+	number = 0;
+	numshift = 0;
+	cp = (unsigned char *) oid->elements;
+	number = (unsigned long) cp[0];
+	sprintf(numstr, "%ld ", number/40);
+	string_length += strlen(numstr);
+	sprintf(numstr, "%ld ", number%40);
+	string_length += strlen(numstr);
+	for (i=1; i<oid->length; i++) {
+		if ( (size_t) (numshift+7) < (sizeof(unsigned long)*8)) {
+			number = (number << 7) | (cp[i] & 0x7f);
+			numshift += 7;
+		}
+		else {
+			*minor_status = 0;
+			return(GSS_S_FAILURE);
+		}
+		if ((cp[i] & 0x80) == 0) {
+			sprintf(numstr, "%ld ", number);
+			string_length += strlen(numstr);
+			number = 0;
+			numshift = 0;
+		}
+	}
+	/*
+	 * If we get here, we've calculated the length of "n n n ... n ".  Add 4
+	 * here for "{ " and "}\0".
+	 */
+	string_length += 4;
+	if ((bp = (char *) malloc(string_length))) {
+		strcpy(bp, "{ ");
+		number = (unsigned long) cp[0];
+		sprintf(numstr, "%ld ", number/40);
+		strcat(bp, numstr);
+		sprintf(numstr, "%ld ", number%40);
+		strcat(bp, numstr);
+		number = 0;
+		cp = (unsigned char *) oid->elements;
+		for (i=1; i<oid->length; i++) {
+			number = (number << 7) | (cp[i] & 0x7f);
+			if ((cp[i] & 0x80) == 0) {
+				sprintf(numstr, "%ld ", number);
+				strcat(bp, numstr);
+				number = 0;
+			}
+		}
+		strcat(bp, "}");
+		oid_str->length = strlen(bp)+1;
+		oid_str->value = (void *) bp;
+		*minor_status = 0;
+		return(GSS_S_COMPLETE);
+	}
+	*minor_status = 0;
+	return(GSS_S_FAILURE);
+}
+#endif
+
+static void
+svc_rpc_gss_build_ucred(struct svc_rpc_gss_client *client,
+    const gss_name_t name)
+{
+	OM_uint32		maj_stat, min_stat;
+	char			buf[128];
+	uid_t			uid;
+	struct passwd		pwd, *pw;
+	rpc_gss_ucred_t		*uc = &client->cl_ucred;
+
+	uc->uid = 65534;
+	uc->gid = 65534;
+	uc->gidlen = 0;
+	uc->gidlist = client->cl_gid_storage;
+
+	maj_stat = gss_pname_to_uid(&min_stat, name, client->cl_mech, &uid);
+	if (maj_stat != GSS_S_COMPLETE)
+		return;
+
+	getpwuid_r(uid, &pwd, buf, sizeof(buf), &pw);
+	if (pw) {
+		int len = NGRPS;
+		uc->uid = pw->pw_uid;
+		uc->gid = pw->pw_gid;
+		uc->gidlist = client->cl_gid_storage;
+		getgrouplist(pw->pw_name, pw->pw_gid, uc->gidlist, &len);
+		uc->gidlen = len;
+	}
+}
+
+static bool_t
+svc_rpc_gss_accept_sec_context(struct svc_rpc_gss_client *client,
+			       struct svc_req *rqst,
+			       struct rpc_gss_init_res *gr,
+			       struct rpc_gss_cred *gc)
+{
+	gss_buffer_desc		recv_tok;
+	gss_OID			mech;
+	OM_uint32		maj_stat = 0, min_stat = 0, ret_flags;
+	OM_uint32		cred_lifetime;
+	struct svc_rpc_gss_svc_name *sname;
+
+	log_debug("in svc_rpc_gss_accept_context()");
+	
+	/* Deserialize arguments. */
+	memset(&recv_tok, 0, sizeof(recv_tok));
+	
+	if (!svc_getargs(rqst->rq_xprt,
+		(xdrproc_t) xdr_gss_buffer_desc,
+		(caddr_t) &recv_tok)) {
+		client->cl_state = CLIENT_STALE;
+		return (FALSE);
+	}
+
+	/*
+	 * First time round, try all the server names we have until
+	 * one matches. Afterwards, stick with that one.
+	 */
+	if (!client->cl_sname) {
+		SLIST_FOREACH(sname, &svc_rpc_gss_svc_names, sn_link) {
+			if (sname->sn_program == rqst->rq_prog
+			    && sname->sn_version == rqst->rq_vers) {
+				gr->gr_major = gss_accept_sec_context(
+					&gr->gr_minor,
+					&client->cl_ctx,
+					sname->sn_cred,
+					&recv_tok,
+					GSS_C_NO_CHANNEL_BINDINGS,
+					&client->cl_cname,
+					&mech,
+					&gr->gr_token,
+					&ret_flags,
+					&cred_lifetime,
+					&client->cl_creds);
+				if (gr->gr_major == GSS_S_COMPLETE
+				    || gr->gr_major == GSS_S_CONTINUE_NEEDED) {
+					client->cl_sname = sname;
+					break;
+				}
+			}
+		}
+	} else {
+		gr->gr_major = gss_accept_sec_context(
+			&gr->gr_minor,
+			&client->cl_ctx,
+			client->cl_sname->sn_cred,
+			&recv_tok,
+			GSS_C_NO_CHANNEL_BINDINGS,
+			&client->cl_cname,
+			&mech,
+			&gr->gr_token,
+			&ret_flags,
+			&cred_lifetime,
+			NULL);
+	}
+	
+	xdr_free((xdrproc_t) xdr_gss_buffer_desc, (char *) &recv_tok);
+
+	/*
+	 * If we get an error from gss_accept_sec_context, send the
+	 * reply anyway so that the client gets a chance to see what
+	 * is wrong.
+	 */
+	if (gr->gr_major != GSS_S_COMPLETE &&
+	    gr->gr_major != GSS_S_CONTINUE_NEEDED) {
+		log_status("accept_sec_context", client->cl_mech,
+		    gr->gr_major, gr->gr_minor);
+		client->cl_state = CLIENT_STALE;
+		return (FALSE);
+	}
+
+	gr->gr_handle.value = &client->cl_id;
+	gr->gr_handle.length = sizeof(uint32_t);
+	gr->gr_win = SVC_RPC_GSS_SEQWINDOW;
+	
+	/* Save client info. */
+	client->cl_mech = mech;
+	client->cl_qop = GSS_C_QOP_DEFAULT;
+	client->cl_seq = gc->gc_seq;
+	client->cl_win = gr->gr_win;
+	client->cl_done_callback = FALSE;
+
+	if (gr->gr_major == GSS_S_COMPLETE) {
+		gss_buffer_desc	export_name;
+
+		/*
+		 * Change client expiration time to be near when the
+		 * client creds expire (or 24 hours if we can't figure
+		 * that out).
+		 */
+		if (cred_lifetime == GSS_C_INDEFINITE)
+			cred_lifetime = time(0) + 24*60*60;
+
+		client->cl_expiration = time(0) + cred_lifetime;
+
+		/*
+		 * Fill in cred details in the rawcred structure.
+		 */
+		client->cl_rawcred.version = RPCSEC_GSS_VERSION;
+		rpc_gss_oid_to_mech(mech, &client->cl_rawcred.mechanism);
+		maj_stat = gss_export_name(&min_stat, client->cl_cname,
+		    &export_name);
+		if (maj_stat != GSS_S_COMPLETE) {
+			log_status("gss_export_name", client->cl_mech,
+			    maj_stat, min_stat);
+			return (FALSE);
+		}
+		client->cl_rawcred.client_principal =
+			malloc(sizeof(*client->cl_rawcred.client_principal)
+			    + export_name.length);
+		client->cl_rawcred.client_principal->len = export_name.length;
+		memcpy(client->cl_rawcred.client_principal->name,
+		    export_name.value, export_name.length);
+		gss_release_buffer(&min_stat, &export_name);
+		client->cl_rawcred.svc_principal =
+			client->cl_sname->sn_principal;
+		client->cl_rawcred.service = gc->gc_svc;
+
+		/*
+		 * Use gss_pname_to_uid to map to unix creds. For
+		 * kerberos5, this uses krb5_aname_to_localname.
+		 */
+		svc_rpc_gss_build_ucred(client, client->cl_cname);
+
+#ifdef DEBUG
+		{
+			gss_buffer_desc mechname;
+
+			gss_oid_to_str(&min_stat, mech, &mechname);
+			
+			log_debug("accepted context for %s with "
+			    "<mech %.*s, qop %d, svc %d>",
+			    client->cl_rawcred.client_principal->name,
+			    mechname.length, (char *)mechname.value,
+			    client->cl_qop, client->rawcred.service);
+
+			gss_release_buffer(&min_stat, &mechname);
+		}
+#endif /* DEBUG */
+	}
+	return (TRUE);
+}
+
+static bool_t
+svc_rpc_gss_validate(struct svc_rpc_gss_client *client, struct rpc_msg *msg,
+	gss_qop_t *qop)
+{
+	struct opaque_auth	*oa;
+	gss_buffer_desc		 rpcbuf, checksum;
+	OM_uint32		 maj_stat, min_stat;
+	gss_qop_t		 qop_state;
+	u_char			 rpchdr[128];
+	int32_t			*buf;
+
+	log_debug("in svc_rpc_gss_validate()");
+	
+	memset(rpchdr, 0, sizeof(rpchdr));
+
+	/* Reconstruct RPC header for signing (from xdr_callmsg). */
+	buf = (int32_t *)rpchdr;
+	IXDR_PUT_LONG(buf, msg->rm_xid);
+	IXDR_PUT_ENUM(buf, msg->rm_direction);
+	IXDR_PUT_LONG(buf, msg->rm_call.cb_rpcvers);
+	IXDR_PUT_LONG(buf, msg->rm_call.cb_prog);
+	IXDR_PUT_LONG(buf, msg->rm_call.cb_vers);
+	IXDR_PUT_LONG(buf, msg->rm_call.cb_proc);
+	oa = &msg->rm_call.cb_cred;
+	IXDR_PUT_ENUM(buf, oa->oa_flavor);
+	IXDR_PUT_LONG(buf, oa->oa_length);
+	if (oa->oa_length) {
+		memcpy((caddr_t)buf, oa->oa_base, oa->oa_length);
+		buf += RNDUP(oa->oa_length) / sizeof(int32_t);
+	}
+	rpcbuf.value = rpchdr;
+	rpcbuf.length = (u_char *)buf - rpchdr;
+
+	checksum.value = msg->rm_call.cb_verf.oa_base;
+	checksum.length = msg->rm_call.cb_verf.oa_length;
+	
+	maj_stat = gss_verify_mic(&min_stat, client->cl_ctx, &rpcbuf, &checksum,
+				  &qop_state);
+	
+	if (maj_stat != GSS_S_COMPLETE) {
+		log_status("gss_verify_mic", client->cl_mech,
+		    maj_stat, min_stat);
+		client->cl_state = CLIENT_STALE;
+		return (FALSE);
+	}
+	*qop = qop_state;
+	return (TRUE);
+}
+
+static bool_t
+svc_rpc_gss_nextverf(struct svc_rpc_gss_client *client,
+    struct svc_req *rqst, u_int seq)
+{
+	gss_buffer_desc		signbuf;
+	OM_uint32		maj_stat, min_stat;
+	uint32_t		nseq;       
+
+	log_debug("in svc_rpc_gss_nextverf()");
+
+	nseq = htonl(seq);
+	signbuf.value = &nseq;
+	signbuf.length = sizeof(nseq);
+
+	if (client->cl_verf.value)
+		gss_release_buffer(&min_stat, &client->cl_verf);
+
+	maj_stat = gss_get_mic(&min_stat, client->cl_ctx, client->cl_qop,
+	    &signbuf, &client->cl_verf);
+
+	if (maj_stat != GSS_S_COMPLETE) {
+		log_status("gss_get_mic", client->cl_mech, maj_stat, min_stat);
+		client->cl_state = CLIENT_STALE;
+		return (FALSE);
+	}
+	rqst->rq_xprt->xp_verf.oa_flavor = RPCSEC_GSS;
+	rqst->rq_xprt->xp_verf.oa_base = (caddr_t)client->cl_verf.value;
+	rqst->rq_xprt->xp_verf.oa_length = (u_int)client->cl_verf.length;
+	
+	return (TRUE);
+}
+
+static bool_t
+svc_rpc_gss_callback(struct svc_rpc_gss_client *client, struct svc_req *rqst)
+{
+	struct svc_rpc_gss_callback *scb;
+	rpc_gss_lock_t	lock;
+	void		*cookie;
+	bool_t		cb_res;
+	bool_t		result;
+
+	/*
+	 * See if we have a callback for this guy.
+	 */
+	result = TRUE;
+	SLIST_FOREACH(scb, &svc_rpc_gss_callbacks, cb_link) {
+		if (scb->cb_callback.program == rqst->rq_prog
+		    && scb->cb_callback.version == rqst->rq_vers) {
+			/*
+			 * This one matches. Call the callback and see
+			 * if it wants to veto or something.
+			 */
+			lock.locked = FALSE;
+			lock.raw_cred = &client->cl_rawcred;
+			cb_res = scb->cb_callback.callback(rqst,
+			    client->cl_creds,
+			    client->cl_ctx,
+			    &lock,
+			    &cookie);
+
+			if (!cb_res) {
+				client->cl_state = CLIENT_STALE;
+				result = FALSE;
+				break;
+			}
+
+			/*
+			 * The callback accepted the connection - it
+			 * is responsible for freeing client->cl_creds
+			 * now.
+			 */
+			client->cl_creds = GSS_C_NO_CREDENTIAL;
+			client->cl_locked = lock.locked;
+			client->cl_cookie = cookie;
+			return (TRUE);
+		}
+	}
+
+	/*
+	 * Either no callback exists for this program/version or one
+	 * of the callbacks rejected the connection. We just need to
+	 * clean up the delegated client creds, if any.
+	 */
+	if (client->cl_creds) {
+		OM_uint32 min_ver;
+		gss_release_cred(&min_ver, &client->cl_creds);
+	}
+	return (result);
+}
+
+static bool_t
+svc_rpc_gss_check_replay(struct svc_rpc_gss_client *client, uint32_t seq)
+{
+	u_int32_t offset;
+	int word, bit;
+
+	if (seq < client->cl_seqlast) {
+		/*
+		 * The request sequence number is less than
+		 * the largest we have seen so far. If it is
+		 * outside the window or if we have seen a
+		 * request with this sequence before, silently
+		 * discard it.
+		 */
+		offset = client->cl_seqlast - seq;
+		if (offset >= client->cl_win)
+			return (FALSE);
+		word = offset / 32;
+		bit = offset % 32;
+		if (client->cl_seqmask[word] & (1 << bit))
+			return (FALSE);
+		client->cl_seqmask[word] |= (1 << bit);
+	}
+
+	return (TRUE);
+}
+
+static void
+svc_rpc_gss_update_seq(struct svc_rpc_gss_client *client, uint32_t seq)
+{
+	int offset, i;
+	uint32_t carry, newcarry;
+
+	if (seq > client->cl_seqlast) {
+		/*
+		 * This request has a sequence number greater
+		 * than any we have seen so far. Advance the
+		 * seq window and set bit zero of the window
+		 * (which corresponds to the new sequence
+		 * number)
+		 */
+		offset = seq - client->cl_seqlast;
+		while (offset > 32) {
+			for (i = (SVC_RPC_GSS_SEQWINDOW / 32) - 1;
+			     i > 0; i--) {
+				client->cl_seqmask[i] = client->cl_seqmask[i-1];
+			}
+			client->cl_seqmask[0] = 0;
+			offset -= 32;
+		}
+		carry = 0;
+		for (i = 0; i < SVC_RPC_GSS_SEQWINDOW / 32; i++) {
+			newcarry = client->cl_seqmask[i] >> (32 - offset);
+			client->cl_seqmask[i] =
+				(client->cl_seqmask[i] << offset) | carry;
+			carry = newcarry;
+		}
+		client->cl_seqmask[0] |= 1;
+		client->cl_seqlast = seq;
+	}
+}
+
+enum auth_stat
+svc_rpc_gss(struct svc_req *rqst, struct rpc_msg *msg)
+
+{
+	OM_uint32		 min_stat;
+	XDR	 		 xdrs;
+	struct svc_rpc_gss_client *client;
+	struct rpc_gss_cred	 gc;
+	struct rpc_gss_init_res	 gr;
+	gss_qop_t		 qop;
+	int			 call_stat;
+	enum auth_stat		 result;
+	
+	log_debug("in svc_rpc_gss()");
+	
+	/* Garbage collect old clients. */
+	svc_rpc_gss_timeout_clients();
+
+	/* Initialize reply. */
+	rqst->rq_xprt->xp_verf = _null_auth;
+
+	/* Deserialize client credentials. */
+	if (rqst->rq_cred.oa_length <= 0)
+		return (AUTH_BADCRED);
+	
+	memset(&gc, 0, sizeof(gc));
+	
+	xdrmem_create(&xdrs, rqst->rq_cred.oa_base,
+	    rqst->rq_cred.oa_length, XDR_DECODE);
+	
+	if (!xdr_rpc_gss_cred(&xdrs, &gc)) {
+		XDR_DESTROY(&xdrs);
+		return (AUTH_BADCRED);
+	}
+	XDR_DESTROY(&xdrs);
+
+	/* Check version. */
+	if (gc.gc_version != RPCSEC_GSS_VERSION) {
+		result = AUTH_BADCRED;
+		goto out;
+	}
+
+	/* Check the proc and find the client (or create it) */
+	if (gc.gc_proc == RPCSEC_GSS_INIT) {
+		client = svc_rpc_gss_create_client();
+	} else {
+		if (gc.gc_handle.length != sizeof(uint32_t)) {
+			result = AUTH_BADCRED;
+			goto out;
+		}
+		uint32_t *p = gc.gc_handle.value;
+		client = svc_rpc_gss_find_client(*p);
+		if (!client) {
+			/*
+			 * Can't find the client - we may have
+			 * destroyed it - tell the other side to
+			 * re-authenticate.
+			 */
+			result = RPCSEC_GSS_CREDPROBLEM;
+			goto out;
+		}
+	}
+	rqst->rq_clntcred = client;
+
+	/*
+	 * The service and sequence number must be ignored for
+	 * RPCSEC_GSS_INIT and RPCSEC_GSS_CONTINUE_INIT.
+	 */
+	if (gc.gc_proc != RPCSEC_GSS_INIT
+	    && gc.gc_proc != RPCSEC_GSS_CONTINUE_INIT) {
+		/*
+		 * Check for sequence number overflow.
+		 */
+		if (gc.gc_seq >= MAXSEQ) {
+			result = RPCSEC_GSS_CTXPROBLEM;
+			goto out;
+		}
+		client->cl_seq = gc.gc_seq;
+
+		/*
+		 * Check for valid service.
+		 */
+		if (gc.gc_svc != rpc_gss_svc_none &&
+		    gc.gc_svc != rpc_gss_svc_integrity &&
+		    gc.gc_svc != rpc_gss_svc_privacy) {
+			result = AUTH_BADCRED;
+			goto out;
+		}
+	}
+
+	/* Handle RPCSEC_GSS control procedure. */
+	switch (gc.gc_proc) {
+
+	case RPCSEC_GSS_INIT:
+	case RPCSEC_GSS_CONTINUE_INIT:
+		if (rqst->rq_proc != NULLPROC) {
+			result = AUTH_REJECTEDCRED;
+			break;
+		}
+
+		memset(&gr, 0, sizeof(gr));
+		if (!svc_rpc_gss_accept_sec_context(client, rqst, &gr, &gc)) {
+			result = AUTH_REJECTEDCRED;
+			break;
+		}
+
+		if (gr.gr_major == GSS_S_COMPLETE) {
+			if (!svc_rpc_gss_nextverf(client, rqst, gr.gr_win)) {
+				result = AUTH_REJECTEDCRED;
+				break;
+			}
+		} else {
+			rqst->rq_xprt->xp_verf.oa_flavor = AUTH_NULL;
+			rqst->rq_xprt->xp_verf.oa_length = 0;
+		}
+		
+		call_stat = svc_sendreply(rqst->rq_xprt,
+		    (xdrproc_t) xdr_rpc_gss_init_res,
+		    (caddr_t) &gr);
+
+		gss_release_buffer(&min_stat, &gr.gr_token);
+
+		if (!call_stat) {
+			result = AUTH_FAILED;
+			break;
+		}
+
+		if (gr.gr_major == GSS_S_COMPLETE)
+			client->cl_state = CLIENT_ESTABLISHED;
+
+		result = RPCSEC_GSS_NODISPATCH;
+		break;
+		
+	case RPCSEC_GSS_DATA:
+	case RPCSEC_GSS_DESTROY:
+		if (!svc_rpc_gss_check_replay(client, gc.gc_seq)) {
+			result = RPCSEC_GSS_NODISPATCH;
+			break;
+		}
+
+		if (!svc_rpc_gss_validate(client, msg, &qop)) {
+			result = RPCSEC_GSS_CREDPROBLEM;
+			break;
+		}
+		
+		if (!svc_rpc_gss_nextverf(client, rqst, gc.gc_seq)) {
+			result = RPCSEC_GSS_CTXPROBLEM;
+			break;
+		}
+
+		svc_rpc_gss_update_seq(client, gc.gc_seq);
+
+		/*
+		 * Change the SVCAUTH ops on the transport to point at
+		 * our own code so that we can unwrap the arguments
+		 * and wrap the result. The caller will re-set this on
+		 * every request to point to a set of null wrap/unwrap
+		 * methods.
+		 */
+		SVC_AUTH(rqst->rq_xprt).svc_ah_ops = &svc_auth_gss_ops;
+		SVC_AUTH(rqst->rq_xprt).svc_ah_private = client;
+
+		if (gc.gc_proc == RPCSEC_GSS_DATA) {
+			/*
+			 * We might be ready to do a callback to the server to
+			 * see if it wants to accept/reject the connection.
+			 */
+			if (!client->cl_done_callback) {
+				client->cl_done_callback = TRUE;
+				client->cl_qop = qop;
+				client->cl_rawcred.qop = _rpc_gss_num_to_qop(
+					client->cl_rawcred.mechanism, qop);
+				if (!svc_rpc_gss_callback(client, rqst)) {
+					result = AUTH_REJECTEDCRED;
+					break;
+				}
+			}
+
+			/*
+			 * If the server has locked this client to a
+			 * particular service+qop pair, enforce that
+			 * restriction now.
+			 */
+			if (client->cl_locked) {
+				if (client->cl_rawcred.service != gc.gc_svc) {
+					result = AUTH_FAILED;
+					break;
+				} else if (client->cl_qop != qop) {
+					result = AUTH_BADVERF;
+					break;
+				}
+			}
+
+			/*
+			 * If the qop changed, look up the new qop
+			 * name for rawcred.
+			 */
+			if (client->cl_qop != qop) {
+				client->cl_qop = qop;
+				client->cl_rawcred.qop = _rpc_gss_num_to_qop(
+					client->cl_rawcred.mechanism, qop);
+			}
+
+			/*
+			 * Make sure we use the right service value
+			 * for unwrap/wrap.
+			 */
+			client->cl_rawcred.service = gc.gc_svc;
+
+			result = AUTH_OK;
+		} else {
+			if (rqst->rq_proc != NULLPROC) {
+				result = AUTH_REJECTEDCRED;
+				break;
+			}
+
+			call_stat = svc_sendreply(rqst->rq_xprt,
+			    (xdrproc_t) xdr_void, (caddr_t) NULL);
+
+			if (!call_stat) {
+				result = AUTH_FAILED;
+				break;
+			}
+
+			svc_rpc_gss_destroy_client(client);
+
+			result = RPCSEC_GSS_NODISPATCH;
+			break;
+		}
+		break;
+
+	default:
+		result = AUTH_BADCRED;
+		break;
+	}
+out:
+	xdr_free((xdrproc_t) xdr_rpc_gss_cred, (char *) &gc);
+	return (result);
+}
+
+bool_t
+svc_rpc_gss_wrap(SVCAUTH *auth, XDR *xdrs, xdrproc_t xdr_func, caddr_t xdr_ptr)
+{
+	struct svc_rpc_gss_client *client;
+	
+	log_debug("in svc_rpc_gss_wrap()");
+
+	client = (struct svc_rpc_gss_client *) auth->svc_ah_private;
+	if (client->cl_state != CLIENT_ESTABLISHED
+	    || client->cl_rawcred.service == rpc_gss_svc_none) {
+		return xdr_func(xdrs, xdr_ptr);
+	}
+	return (xdr_rpc_gss_wrap_data(xdrs, xdr_func, xdr_ptr,
+		client->cl_ctx, client->cl_qop,
+		client->cl_rawcred.service, client->cl_seq));
+}
+
+bool_t
+svc_rpc_gss_unwrap(SVCAUTH *auth, XDR *xdrs, xdrproc_t xdr_func, caddr_t xdr_ptr)
+{
+	struct svc_rpc_gss_client *client;
+
+	log_debug("in svc_rpc_gss_unwrap()");
+	
+	client = (struct svc_rpc_gss_client *) auth->svc_ah_private;
+	if (client->cl_state != CLIENT_ESTABLISHED
+	    || client->cl_rawcred.service == rpc_gss_svc_none) {
+		return xdr_func(xdrs, xdr_ptr);
+	}
+	return (xdr_rpc_gss_unwrap_data(xdrs, xdr_func, xdr_ptr,
+		client->cl_ctx, client->cl_qop,
+		client->cl_rawcred.service, client->cl_seq));
+}