xref: /freebsd/sys/rpc/rpcsec_gss/rpcsec_gss.c (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2008 Doug Rabson
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 /*
29   auth_gss.c
30 
31   RPCSEC_GSS client routines.
32 
33   Copyright (c) 2000 The Regents of the University of Michigan.
34   All rights reserved.
35 
36   Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>.
37   All rights reserved, all wrongs reversed.
38 
39   Redistribution and use in source and binary forms, with or without
40   modification, are permitted provided that the following conditions
41   are met:
42 
43   1. Redistributions of source code must retain the above copyright
44      notice, this list of conditions and the following disclaimer.
45   2. Redistributions in binary form must reproduce the above copyright
46      notice, this list of conditions and the following disclaimer in the
47      documentation and/or other materials provided with the distribution.
48   3. Neither the name of the University nor the names of its
49      contributors may be used to endorse or promote products derived
50      from this software without specific prior written permission.
51 
52   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
53   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
54   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
55   DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
57   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
58   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
59   BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
60   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
61   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
62   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
63 
64   $Id: auth_gss.c,v 1.32 2002/01/15 15:43:00 andros Exp $
65 */
66 
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/hash.h>
70 #include <sys/kernel.h>
71 #include <sys/kobj.h>
72 #include <sys/lock.h>
73 #include <sys/malloc.h>
74 #include <sys/mbuf.h>
75 #include <sys/mutex.h>
76 #include <sys/proc.h>
77 #include <sys/refcount.h>
78 #include <sys/sx.h>
79 #include <sys/ucred.h>
80 
81 #include <rpc/rpc.h>
82 #include <rpc/rpcsec_gss.h>
83 
84 #include <kgssapi/krb5/kcrypto.h>
85 
86 #include "rpcsec_gss_int.h"
87 
88 static void	rpc_gss_nextverf(AUTH*);
89 static bool_t	rpc_gss_marshal(AUTH *, uint32_t, XDR *, struct mbuf *);
90 static bool_t	rpc_gss_init(AUTH *auth, rpc_gss_options_ret_t *options_ret);
91 static bool_t	rpc_gss_refresh(AUTH *, void *);
92 static bool_t	rpc_gss_validate(AUTH *, uint32_t, struct opaque_auth *,
93     struct mbuf **);
94 static void	rpc_gss_destroy(AUTH *);
95 static void	rpc_gss_destroy_context(AUTH *, bool_t);
96 
97 static const struct auth_ops rpc_gss_ops = {
98 	.ah_nextverf =	rpc_gss_nextverf,
99 	.ah_marshal =	rpc_gss_marshal,
100 	.ah_validate =	rpc_gss_validate,
101 	.ah_refresh =	rpc_gss_refresh,
102 	.ah_destroy =	rpc_gss_destroy,
103 };
104 
105 enum rpcsec_gss_state {
106 	RPCSEC_GSS_START,
107 	RPCSEC_GSS_CONTEXT,
108 	RPCSEC_GSS_ESTABLISHED,
109 	RPCSEC_GSS_DESTROYING
110 };
111 
112 struct rpc_pending_request {
113 	uint32_t		pr_xid;		/* XID of rpc */
114 	uint32_t		pr_seq;		/* matching GSS seq */
115 	LIST_ENTRY(rpc_pending_request) pr_link;
116 };
117 LIST_HEAD(rpc_pending_request_list, rpc_pending_request);
118 
119 struct rpc_gss_data {
120 	volatile u_int		gd_refs;	/* number of current users */
121 	struct mtx		gd_lock;
122 	uint32_t		gd_hash;
123 	AUTH			*gd_auth;	/* link back to AUTH */
124 	struct ucred		*gd_ucred;	/* matching local cred */
125 	char			*gd_principal;	/* server principal name */
126 	char			*gd_clntprincipal; /* client principal name */
127 	rpc_gss_options_req_t	gd_options;	/* GSS context options */
128 	enum rpcsec_gss_state	gd_state;	/* connection state */
129 	gss_buffer_desc		gd_verf;	/* save GSS_S_COMPLETE
130 						 * NULL RPC verfier to
131 						 * process at end of
132 						 * context negotiation */
133 	CLIENT			*gd_clnt;	/* client handle */
134 	gss_OID			gd_mech;	/* mechanism to use */
135 	gss_qop_t		gd_qop;		/* quality of protection */
136 	gss_ctx_id_t		gd_ctx;		/* context id */
137 	struct rpc_gss_cred	gd_cred;	/* client credentials */
138 	uint32_t		gd_seq;		/* next sequence number */
139 	u_int			gd_win;		/* sequence window */
140 	struct rpc_pending_request_list gd_reqs;
141 	TAILQ_ENTRY(rpc_gss_data) gd_link;
142 	TAILQ_ENTRY(rpc_gss_data) gd_alllink;
143 };
144 TAILQ_HEAD(rpc_gss_data_list, rpc_gss_data);
145 
146 #define	AUTH_PRIVATE(auth)	((struct rpc_gss_data *)auth->ah_private)
147 
148 static struct timeval AUTH_TIMEOUT = { 25, 0 };
149 
150 #define RPC_GSS_HASH_SIZE	11
151 #define RPC_GSS_MAX		256
152 static struct rpc_gss_data_list rpc_gss_cache[RPC_GSS_HASH_SIZE];
153 static struct rpc_gss_data_list rpc_gss_all;
154 static struct sx rpc_gss_lock;
155 static int rpc_gss_count;
156 
157 static AUTH *rpc_gss_seccreate_int(CLIENT *, struct ucred *, const char *,
158     const char *, gss_OID, rpc_gss_service_t, u_int, rpc_gss_options_req_t *,
159     rpc_gss_options_ret_t *);
160 
161 static void
162 rpc_gss_hashinit(void *dummy)
163 {
164 	int i;
165 
166 	for (i = 0; i < RPC_GSS_HASH_SIZE; i++)
167 		TAILQ_INIT(&rpc_gss_cache[i]);
168 	TAILQ_INIT(&rpc_gss_all);
169 	sx_init(&rpc_gss_lock, "rpc_gss_lock");
170 }
171 SYSINIT(rpc_gss_hashinit, SI_SUB_KMEM, SI_ORDER_ANY, rpc_gss_hashinit, NULL);
172 
173 static uint32_t
174 rpc_gss_hash(const char *principal, gss_OID mech,
175     struct ucred *cred, rpc_gss_service_t service)
176 {
177 	uint32_t h;
178 
179 	h = HASHSTEP(HASHINIT, cred->cr_uid);
180 	h = hash32_str(principal, h);
181 	h = hash32_buf(mech->elements, mech->length, h);
182 	h = HASHSTEP(h, (int) service);
183 
184 	return (h % RPC_GSS_HASH_SIZE);
185 }
186 
187 /*
188  * Simplified interface to create a security association for the
189  * current thread's * ucred.
190  */
191 AUTH *
192 rpc_gss_secfind(CLIENT *clnt, struct ucred *cred, const char *principal,
193     gss_OID mech_oid, rpc_gss_service_t service)
194 {
195 	uint32_t		h, th;
196 	AUTH			*auth;
197 	struct rpc_gss_data	*gd, *tgd;
198 	rpc_gss_options_ret_t	options;
199 
200 	if (rpc_gss_count > RPC_GSS_MAX) {
201 		while (rpc_gss_count > RPC_GSS_MAX) {
202 			sx_xlock(&rpc_gss_lock);
203 			tgd = TAILQ_FIRST(&rpc_gss_all);
204 			th = tgd->gd_hash;
205 			TAILQ_REMOVE(&rpc_gss_cache[th], tgd, gd_link);
206 			TAILQ_REMOVE(&rpc_gss_all, tgd, gd_alllink);
207 			rpc_gss_count--;
208 			sx_xunlock(&rpc_gss_lock);
209 			AUTH_DESTROY(tgd->gd_auth);
210 		}
211 	}
212 
213 	/*
214 	 * See if we already have an AUTH which matches.
215 	 */
216 	h = rpc_gss_hash(principal, mech_oid, cred, service);
217 
218 again:
219 	sx_slock(&rpc_gss_lock);
220 	TAILQ_FOREACH(gd, &rpc_gss_cache[h], gd_link) {
221 		if (gd->gd_ucred->cr_uid == cred->cr_uid
222 		    && !strcmp(gd->gd_principal, principal)
223 		    && gd->gd_mech == mech_oid
224 		    && gd->gd_cred.gc_svc == service) {
225 			refcount_acquire(&gd->gd_refs);
226 			if (sx_try_upgrade(&rpc_gss_lock)) {
227 				/*
228 				 * Keep rpc_gss_all LRU sorted.
229 				 */
230 				TAILQ_REMOVE(&rpc_gss_all, gd, gd_alllink);
231 				TAILQ_INSERT_TAIL(&rpc_gss_all, gd,
232 				    gd_alllink);
233 				sx_xunlock(&rpc_gss_lock);
234 			} else {
235 				sx_sunlock(&rpc_gss_lock);
236 			}
237 
238 			/*
239 			 * If the state != ESTABLISHED, try and initialize
240 			 * the authenticator again. This will happen if the
241 			 * user's credentials have expired. It may succeed now,
242 			 * if they have done a kinit or similar.
243 			 */
244 			if (gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
245 				memset(&options, 0, sizeof (options));
246 				(void) rpc_gss_init(gd->gd_auth, &options);
247 			}
248 			return (gd->gd_auth);
249 		}
250 	}
251 	sx_sunlock(&rpc_gss_lock);
252 
253 	/*
254 	 * We missed in the cache - create a new association.
255 	 */
256 	auth = rpc_gss_seccreate_int(clnt, cred, NULL, principal, mech_oid,
257 	    service, GSS_C_QOP_DEFAULT, NULL, NULL);
258 	if (!auth)
259 		return (NULL);
260 
261 	gd = AUTH_PRIVATE(auth);
262 	gd->gd_hash = h;
263 
264 	sx_xlock(&rpc_gss_lock);
265 	TAILQ_FOREACH(tgd, &rpc_gss_cache[h], gd_link) {
266 		if (tgd->gd_ucred->cr_uid == cred->cr_uid
267 		    && !strcmp(tgd->gd_principal, principal)
268 		    && tgd->gd_mech == mech_oid
269 		    && tgd->gd_cred.gc_svc == service) {
270 			/*
271 			 * We lost a race to create the AUTH that
272 			 * matches this cred.
273 			 */
274 			sx_xunlock(&rpc_gss_lock);
275 			AUTH_DESTROY(auth);
276 			goto again;
277 		}
278 	}
279 
280 	rpc_gss_count++;
281 	TAILQ_INSERT_TAIL(&rpc_gss_cache[h], gd, gd_link);
282 	TAILQ_INSERT_TAIL(&rpc_gss_all, gd, gd_alllink);
283 	refcount_acquire(&gd->gd_refs);	/* one for the cache, one for user */
284 	sx_xunlock(&rpc_gss_lock);
285 
286 	return (auth);
287 }
288 
289 void
290 rpc_gss_secpurge(CLIENT *clnt)
291 {
292 	uint32_t		h;
293 	struct rpc_gss_data	*gd, *tgd;
294 
295 	TAILQ_FOREACH_SAFE(gd, &rpc_gss_all, gd_alllink, tgd) {
296 		if (gd->gd_clnt == clnt) {
297 			sx_xlock(&rpc_gss_lock);
298 			h = gd->gd_hash;
299 			TAILQ_REMOVE(&rpc_gss_cache[h], gd, gd_link);
300 			TAILQ_REMOVE(&rpc_gss_all, gd, gd_alllink);
301 			rpc_gss_count--;
302 			sx_xunlock(&rpc_gss_lock);
303 			AUTH_DESTROY(gd->gd_auth);
304 		}
305 	}
306 }
307 
308 AUTH *
309 rpc_gss_seccreate(CLIENT *clnt, struct ucred *cred, const char *clnt_principal,
310     const char *principal, const char *mechanism, rpc_gss_service_t service,
311     const char *qop, rpc_gss_options_req_t *options_req,
312     rpc_gss_options_ret_t *options_ret)
313 {
314 	gss_OID			oid;
315 	u_int			qop_num;
316 
317 	/*
318 	 * Bail out now if we don't know this mechanism.
319 	 */
320 	if (!rpc_gss_mech_to_oid(mechanism, &oid))
321 		return (NULL);
322 
323 	if (qop) {
324 		if (!rpc_gss_qop_to_num(qop, mechanism, &qop_num))
325 			return (NULL);
326 	} else {
327 		qop_num = GSS_C_QOP_DEFAULT;
328 	}
329 
330 	return (rpc_gss_seccreate_int(clnt, cred, clnt_principal, principal,
331 		oid, service, qop_num, options_req, options_ret));
332 }
333 
334 void
335 rpc_gss_refresh_auth(AUTH *auth)
336 {
337 	struct rpc_gss_data	*gd;
338 	rpc_gss_options_ret_t	options;
339 
340 	gd = AUTH_PRIVATE(auth);
341 	/*
342 	 * If the state != ESTABLISHED, try and initialize
343 	 * the authenticator again. This will happen if the
344 	 * user's credentials have expired. It may succeed now,
345 	 * if they have done a kinit or similar.
346 	 */
347 	if (gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
348 		memset(&options, 0, sizeof (options));
349 		(void) rpc_gss_init(auth, &options);
350 	}
351 }
352 
353 static AUTH *
354 rpc_gss_seccreate_int(CLIENT *clnt, struct ucred *cred,
355     const char *clnt_principal, const char *principal, gss_OID mech_oid,
356     rpc_gss_service_t service, u_int qop_num,
357     rpc_gss_options_req_t *options_req, rpc_gss_options_ret_t *options_ret)
358 {
359 	AUTH			*auth;
360 	rpc_gss_options_ret_t	options;
361 	struct rpc_gss_data	*gd;
362 
363 	/*
364 	 * If the caller doesn't want the options, point at local
365 	 * storage to simplify the code below.
366 	 */
367 	if (!options_ret)
368 		options_ret = &options;
369 
370 	/*
371 	 * Default service is integrity.
372 	 */
373 	if (service == rpc_gss_svc_default)
374 		service = rpc_gss_svc_integrity;
375 
376 	memset(options_ret, 0, sizeof(*options_ret));
377 
378 	rpc_gss_log_debug("in rpc_gss_seccreate()");
379 
380 	memset(&rpc_createerr, 0, sizeof(rpc_createerr));
381 
382 	auth = mem_alloc(sizeof(*auth));
383 	if (auth == NULL) {
384 		rpc_createerr.cf_stat = RPC_SYSTEMERROR;
385 		rpc_createerr.cf_error.re_errno = ENOMEM;
386 		return (NULL);
387 	}
388 	gd = mem_alloc(sizeof(*gd));
389 	if (gd == NULL) {
390 		rpc_createerr.cf_stat = RPC_SYSTEMERROR;
391 		rpc_createerr.cf_error.re_errno = ENOMEM;
392 		mem_free(auth, sizeof(*auth));
393 		return (NULL);
394 	}
395 
396 	auth->ah_ops = &rpc_gss_ops;
397 	auth->ah_private = (caddr_t) gd;
398 	auth->ah_cred.oa_flavor = RPCSEC_GSS;
399 
400 	refcount_init(&gd->gd_refs, 1);
401 	mtx_init(&gd->gd_lock, "gd->gd_lock", NULL, MTX_DEF);
402 	gd->gd_auth = auth;
403 	gd->gd_ucred = crdup(cred);
404 	gd->gd_principal = strdup(principal, M_RPC);
405 	if (clnt_principal != NULL)
406 		gd->gd_clntprincipal = strdup(clnt_principal, M_RPC);
407 	else
408 		gd->gd_clntprincipal = NULL;
409 
410 
411 	if (options_req) {
412 		gd->gd_options = *options_req;
413 	} else {
414 		gd->gd_options.req_flags = GSS_C_MUTUAL_FLAG;
415 		gd->gd_options.time_req = 0;
416 		gd->gd_options.my_cred = GSS_C_NO_CREDENTIAL;
417 		gd->gd_options.input_channel_bindings = NULL;
418 	}
419 	CLNT_ACQUIRE(clnt);
420 	gd->gd_clnt = clnt;
421 	gd->gd_ctx = GSS_C_NO_CONTEXT;
422 	gd->gd_mech = mech_oid;
423 	gd->gd_qop = qop_num;
424 
425 	gd->gd_cred.gc_version = RPCSEC_GSS_VERSION;
426 	gd->gd_cred.gc_proc = RPCSEC_GSS_INIT;
427 	gd->gd_cred.gc_seq = 0;
428 	gd->gd_cred.gc_svc = service;
429 	LIST_INIT(&gd->gd_reqs);
430 
431 	if (!rpc_gss_init(auth, options_ret)) {
432 		goto bad;
433 	}
434 
435 	return (auth);
436 
437  bad:
438 	AUTH_DESTROY(auth);
439 	return (NULL);
440 }
441 
442 bool_t
443 rpc_gss_set_defaults(AUTH *auth, rpc_gss_service_t service, const char *qop)
444 {
445 	struct rpc_gss_data	*gd;
446 	u_int			qop_num;
447 	const char		*mechanism;
448 
449 	gd = AUTH_PRIVATE(auth);
450 	if (!rpc_gss_oid_to_mech(gd->gd_mech, &mechanism)) {
451 		return (FALSE);
452 	}
453 
454 	if (qop) {
455 		if (!rpc_gss_qop_to_num(qop, mechanism, &qop_num)) {
456 			return (FALSE);
457 		}
458 	} else {
459 		qop_num = GSS_C_QOP_DEFAULT;
460 	}
461 
462 	gd->gd_cred.gc_svc = service;
463 	gd->gd_qop = qop_num;
464 	return (TRUE);
465 }
466 
467 static void
468 rpc_gss_purge_xid(struct rpc_gss_data *gd, uint32_t xid)
469 {
470 	struct rpc_pending_request *pr, *npr;
471 	struct rpc_pending_request_list reqs;
472 
473 	LIST_INIT(&reqs);
474 	mtx_lock(&gd->gd_lock);
475 	LIST_FOREACH_SAFE(pr, &gd->gd_reqs, pr_link, npr) {
476 		if (pr->pr_xid == xid) {
477 			LIST_REMOVE(pr, pr_link);
478 			LIST_INSERT_HEAD(&reqs, pr, pr_link);
479 		}
480 	}
481 
482 	mtx_unlock(&gd->gd_lock);
483 
484 	LIST_FOREACH_SAFE(pr, &reqs, pr_link, npr) {
485 		mem_free(pr, sizeof(*pr));
486 	}
487 }
488 
489 static uint32_t
490 rpc_gss_alloc_seq(struct rpc_gss_data *gd)
491 {
492 	uint32_t seq;
493 
494 	mtx_lock(&gd->gd_lock);
495 	seq = gd->gd_seq;
496 	gd->gd_seq++;
497 	mtx_unlock(&gd->gd_lock);
498 
499 	return (seq);
500 }
501 
502 static void
503 rpc_gss_nextverf(__unused AUTH *auth)
504 {
505 
506 	/* not used */
507 }
508 
509 static bool_t
510 rpc_gss_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args)
511 {
512 	struct rpc_gss_data	*gd;
513 	struct rpc_pending_request *pr;
514 	uint32_t		 seq;
515 	XDR			 tmpxdrs;
516 	struct rpc_gss_cred	 gsscred;
517 	char			 credbuf[MAX_AUTH_BYTES];
518 	struct opaque_auth	 creds, verf;
519 	gss_buffer_desc		 rpcbuf, checksum;
520 	OM_uint32		 maj_stat, min_stat;
521 	bool_t			 xdr_stat;
522 
523 	rpc_gss_log_debug("in rpc_gss_marshal()");
524 
525 	gd = AUTH_PRIVATE(auth);
526 
527 	gsscred = gd->gd_cred;
528 	seq = rpc_gss_alloc_seq(gd);
529 	gsscred.gc_seq = seq;
530 
531 	xdrmem_create(&tmpxdrs, credbuf, sizeof(credbuf), XDR_ENCODE);
532 	if (!xdr_rpc_gss_cred(&tmpxdrs, &gsscred)) {
533 		XDR_DESTROY(&tmpxdrs);
534 		_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
535 		return (FALSE);
536 	}
537 	creds.oa_flavor = RPCSEC_GSS;
538 	creds.oa_base = credbuf;
539 	creds.oa_length = XDR_GETPOS(&tmpxdrs);
540 	XDR_DESTROY(&tmpxdrs);
541 
542 	xdr_opaque_auth(xdrs, &creds);
543 
544 	if (gd->gd_cred.gc_proc == RPCSEC_GSS_INIT ||
545 	    gd->gd_cred.gc_proc == RPCSEC_GSS_CONTINUE_INIT) {
546 		if (!xdr_opaque_auth(xdrs, &_null_auth)) {
547 			_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
548 			return (FALSE);
549 		}
550 		xdrmbuf_append(xdrs, args);
551 		return (TRUE);
552 	} else {
553 		/*
554 		 * Keep track of this XID + seq pair so that we can do
555 		 * the matching gss_verify_mic in AUTH_VALIDATE.
556 		 */
557 		pr = mem_alloc(sizeof(struct rpc_pending_request));
558 		mtx_lock(&gd->gd_lock);
559 		pr->pr_xid = xid;
560 		pr->pr_seq = seq;
561 		LIST_INSERT_HEAD(&gd->gd_reqs, pr, pr_link);
562 		mtx_unlock(&gd->gd_lock);
563 
564 		/*
565 		 * Checksum serialized RPC header, up to and including
566 		 * credential. For the in-kernel environment, we
567 		 * assume that our XDR stream is on a contiguous
568 		 * memory buffer (e.g. an mbuf).
569 		 */
570 		rpcbuf.length = XDR_GETPOS(xdrs);
571 		XDR_SETPOS(xdrs, 0);
572 		rpcbuf.value = XDR_INLINE(xdrs, rpcbuf.length);
573 
574 		maj_stat = gss_get_mic(&min_stat, gd->gd_ctx, gd->gd_qop,
575 		    &rpcbuf, &checksum);
576 
577 		if (maj_stat != GSS_S_COMPLETE) {
578 			rpc_gss_log_status("gss_get_mic", gd->gd_mech,
579 			    maj_stat, min_stat);
580 			if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
581 				rpc_gss_destroy_context(auth, TRUE);
582 			}
583 			_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, EPERM);
584 			return (FALSE);
585 		}
586 
587 		verf.oa_flavor = RPCSEC_GSS;
588 		verf.oa_base = checksum.value;
589 		verf.oa_length = checksum.length;
590 
591 		xdr_stat = xdr_opaque_auth(xdrs, &verf);
592 		gss_release_buffer(&min_stat, &checksum);
593 		if (!xdr_stat) {
594 			_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
595 			return (FALSE);
596 		}
597 		if (gd->gd_state != RPCSEC_GSS_ESTABLISHED ||
598 		    gd->gd_cred.gc_svc == rpc_gss_svc_none) {
599 			xdrmbuf_append(xdrs, args);
600 			return (TRUE);
601 		} else {
602 			if (!xdr_rpc_gss_wrap_data(&args,
603 				gd->gd_ctx, gd->gd_qop, gd->gd_cred.gc_svc,
604 				seq))
605 				return (FALSE);
606 			xdrmbuf_append(xdrs, args);
607 			return (TRUE);
608 		}
609 	}
610 
611 	return (TRUE);
612 }
613 
614 static bool_t
615 rpc_gss_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf,
616     struct mbuf **resultsp)
617 {
618 	struct rpc_gss_data	*gd;
619 	struct rpc_pending_request *pr, *npr;
620 	struct rpc_pending_request_list reqs;
621 	gss_qop_t		qop_state;
622 	uint32_t		num, seq;
623 	gss_buffer_desc		signbuf, checksum;
624 	OM_uint32		maj_stat, min_stat;
625 
626 	rpc_gss_log_debug("in rpc_gss_validate()");
627 
628 	gd = AUTH_PRIVATE(auth);
629 
630 	/*
631 	 * The client will call us with a NULL verf when it gives up
632 	 * on an XID.
633 	 */
634 	if (!verf) {
635 		rpc_gss_purge_xid(gd, xid);
636 		return (TRUE);
637 	}
638 
639 	if (gd->gd_state == RPCSEC_GSS_CONTEXT) {
640 		/*
641 		 * Save the on the wire verifier to validate last INIT
642 		 * phase packet after decode if the major status is
643 		 * GSS_S_COMPLETE.
644 		 */
645 		if (gd->gd_verf.value)
646 			xdr_free((xdrproc_t) xdr_gss_buffer_desc,
647 			    (char *) &gd->gd_verf);
648 		gd->gd_verf.value = mem_alloc(verf->oa_length);
649 		if (gd->gd_verf.value == NULL) {
650 			printf("gss_validate: out of memory\n");
651 			_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
652 			m_freem(*resultsp);
653 			*resultsp = NULL;
654 			return (FALSE);
655 		}
656 		memcpy(gd->gd_verf.value, verf->oa_base, verf->oa_length);
657 		gd->gd_verf.length = verf->oa_length;
658 
659 		return (TRUE);
660 	}
661 
662 	/*
663 	 * We need to check the verifier against all the requests
664 	 * we've send for this XID - for unreliable protocols, we
665 	 * retransmit with the same XID but different sequence
666 	 * number. We temporarily take this set of requests out of the
667 	 * list so that we can work through the list without having to
668 	 * hold the lock.
669 	 */
670 	mtx_lock(&gd->gd_lock);
671 	LIST_INIT(&reqs);
672 	LIST_FOREACH_SAFE(pr, &gd->gd_reqs, pr_link, npr) {
673 		if (pr->pr_xid == xid) {
674 			LIST_REMOVE(pr, pr_link);
675 			LIST_INSERT_HEAD(&reqs, pr, pr_link);
676 		}
677 	}
678 	mtx_unlock(&gd->gd_lock);
679 	LIST_FOREACH(pr, &reqs, pr_link) {
680 		if (pr->pr_xid == xid) {
681 			seq = pr->pr_seq;
682 			num = htonl(seq);
683 			signbuf.value = &num;
684 			signbuf.length = sizeof(num);
685 
686 			checksum.value = verf->oa_base;
687 			checksum.length = verf->oa_length;
688 
689 			maj_stat = gss_verify_mic(&min_stat, gd->gd_ctx,
690 			    &signbuf, &checksum, &qop_state);
691 			if (maj_stat != GSS_S_COMPLETE
692 			    || qop_state != gd->gd_qop) {
693 				continue;
694 			}
695 			if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
696 				rpc_gss_destroy_context(auth, TRUE);
697 				break;
698 			}
699 			//rpc_gss_purge_reqs(gd, seq);
700 			LIST_FOREACH_SAFE(pr, &reqs, pr_link, npr)
701 				mem_free(pr, sizeof(*pr));
702 
703 			if (gd->gd_cred.gc_svc == rpc_gss_svc_none) {
704 				return (TRUE);
705 			} else {
706 				if (!xdr_rpc_gss_unwrap_data(resultsp,
707 					gd->gd_ctx, gd->gd_qop,
708 					gd->gd_cred.gc_svc, seq)) {
709 					return (FALSE);
710 				}
711 			}
712 			return (TRUE);
713 		}
714 	}
715 
716 	/*
717 	 * We didn't match - put back any entries for this XID so that
718 	 * a future call to validate can retry.
719 	 */
720 	mtx_lock(&gd->gd_lock);
721 	LIST_FOREACH_SAFE(pr, &reqs, pr_link, npr) {
722 		LIST_REMOVE(pr, pr_link);
723 		LIST_INSERT_HEAD(&gd->gd_reqs, pr, pr_link);
724 	}
725 	mtx_unlock(&gd->gd_lock);
726 
727 	/*
728 	 * Nothing matches - give up.
729 	 */
730 	_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, EPERM);
731 	m_freem(*resultsp);
732 	*resultsp = NULL;
733 	return (FALSE);
734 }
735 
736 static bool_t
737 rpc_gss_init(AUTH *auth, rpc_gss_options_ret_t *options_ret)
738 {
739 	struct thread		*td = curthread;
740 	struct ucred		*crsave;
741 	struct rpc_gss_data	*gd;
742 	struct rpc_gss_init_res	 gr;
743 	gss_buffer_desc		principal_desc;
744 	gss_buffer_desc		*recv_tokenp, recv_token, send_token;
745 	gss_name_t		name;
746 	OM_uint32		 maj_stat, min_stat, call_stat;
747 	const char		*mech;
748 	struct rpc_callextra	 ext;
749 	gss_OID			mech_oid;
750 	gss_OID_set		mechlist;
751 
752 	rpc_gss_log_debug("in rpc_gss_refresh()");
753 
754 	gd = AUTH_PRIVATE(auth);
755 
756 	mtx_lock(&gd->gd_lock);
757 	/*
758 	 * If the context isn't in START state, someone else is
759 	 * refreshing - we wait till they are done. If they fail, they
760 	 * will put the state back to START and we can try (most
761 	 * likely to also fail).
762 	 */
763 	while (gd->gd_state != RPCSEC_GSS_START
764 	    && gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
765 		msleep(gd, &gd->gd_lock, 0, "gssstate", 0);
766 	}
767 	if (gd->gd_state == RPCSEC_GSS_ESTABLISHED) {
768 		mtx_unlock(&gd->gd_lock);
769 		return (TRUE);
770 	}
771 	gd->gd_state = RPCSEC_GSS_CONTEXT;
772 	mtx_unlock(&gd->gd_lock);
773 
774 	gd->gd_cred.gc_proc = RPCSEC_GSS_INIT;
775 	gd->gd_cred.gc_seq = 0;
776 
777 	/*
778 	 * For KerberosV, if there is a client principal name, that implies
779 	 * that this is a host based initiator credential in the default
780 	 * keytab file. For this case, it is necessary to do a
781 	 * gss_acquire_cred(). When this is done, the gssd daemon will
782 	 * do the equivalent of "kinit -k" to put a TGT for the name in
783 	 * the credential cache file for the gssd daemon.
784 	 */
785 	if (gd->gd_clntprincipal != NULL &&
786 	    rpc_gss_mech_to_oid("kerberosv5", &mech_oid) &&
787 	    gd->gd_mech == mech_oid) {
788 		/* Get rid of any old credential. */
789 		if (gd->gd_options.my_cred != GSS_C_NO_CREDENTIAL) {
790 			gss_release_cred(&min_stat, &gd->gd_options.my_cred);
791 			gd->gd_options.my_cred = GSS_C_NO_CREDENTIAL;
792 		}
793 
794 		/*
795 		 * The mechanism must be set to KerberosV for acquisition
796 		 * of credentials to work reliably.
797 		 */
798 		maj_stat = gss_create_empty_oid_set(&min_stat, &mechlist);
799 		if (maj_stat != GSS_S_COMPLETE) {
800 			options_ret->major_status = maj_stat;
801 			options_ret->minor_status = min_stat;
802 			goto out;
803 		}
804 		maj_stat = gss_add_oid_set_member(&min_stat, gd->gd_mech,
805 		    &mechlist);
806 		if (maj_stat != GSS_S_COMPLETE) {
807 			options_ret->major_status = maj_stat;
808 			options_ret->minor_status = min_stat;
809 			gss_release_oid_set(&min_stat, &mechlist);
810 			goto out;
811 		}
812 
813 		principal_desc.value = (void *)gd->gd_clntprincipal;
814 		principal_desc.length = strlen(gd->gd_clntprincipal);
815 		maj_stat = gss_import_name(&min_stat, &principal_desc,
816 		    GSS_C_NT_HOSTBASED_SERVICE, &name);
817 		if (maj_stat != GSS_S_COMPLETE) {
818 			options_ret->major_status = maj_stat;
819 			options_ret->minor_status = min_stat;
820 			gss_release_oid_set(&min_stat, &mechlist);
821 			goto out;
822 		}
823 		/* Acquire the credentials. */
824 		maj_stat = gss_acquire_cred(&min_stat, name, 0,
825 		    mechlist, GSS_C_INITIATE,
826 		    &gd->gd_options.my_cred, NULL, NULL);
827 		gss_release_name(&min_stat, &name);
828 		gss_release_oid_set(&min_stat, &mechlist);
829 		if (maj_stat != GSS_S_COMPLETE) {
830 			options_ret->major_status = maj_stat;
831 			options_ret->minor_status = min_stat;
832 			goto out;
833 		}
834 	}
835 
836 	principal_desc.value = (void *)gd->gd_principal;
837 	principal_desc.length = strlen(gd->gd_principal);
838 	maj_stat = gss_import_name(&min_stat, &principal_desc,
839 	    GSS_C_NT_HOSTBASED_SERVICE, &name);
840 	if (maj_stat != GSS_S_COMPLETE) {
841 		options_ret->major_status = maj_stat;
842 		options_ret->minor_status = min_stat;
843 		goto out;
844 	}
845 
846 	/* GSS context establishment loop. */
847 	memset(&recv_token, 0, sizeof(recv_token));
848 	memset(&gr, 0, sizeof(gr));
849 	memset(options_ret, 0, sizeof(*options_ret));
850 	options_ret->major_status = GSS_S_FAILURE;
851 	recv_tokenp = GSS_C_NO_BUFFER;
852 
853 	for (;;) {
854 		crsave = td->td_ucred;
855 		td->td_ucred = gd->gd_ucred;
856 		maj_stat = gss_init_sec_context(&min_stat,
857 		    gd->gd_options.my_cred,
858 		    &gd->gd_ctx,
859 		    name,
860 		    gd->gd_mech,
861 		    gd->gd_options.req_flags,
862 		    gd->gd_options.time_req,
863 		    gd->gd_options.input_channel_bindings,
864 		    recv_tokenp,
865 		    &gd->gd_mech,	/* used mech */
866 		    &send_token,
867 		    &options_ret->ret_flags,
868 		    &options_ret->time_req);
869 		td->td_ucred = crsave;
870 
871 		/*
872 		 * Free the token which we got from the server (if
873 		 * any).  Remember that this was allocated by XDR, not
874 		 * GSS-API.
875 		 */
876 		if (recv_tokenp != GSS_C_NO_BUFFER) {
877 			xdr_free((xdrproc_t) xdr_gss_buffer_desc,
878 			    (char *) &recv_token);
879 			recv_tokenp = GSS_C_NO_BUFFER;
880 		}
881 		if (gd->gd_mech && rpc_gss_oid_to_mech(gd->gd_mech, &mech)) {
882 			strlcpy(options_ret->actual_mechanism,
883 			    mech,
884 			    sizeof(options_ret->actual_mechanism));
885 		}
886 		if (maj_stat != GSS_S_COMPLETE &&
887 		    maj_stat != GSS_S_CONTINUE_NEEDED) {
888 			rpc_gss_log_status("gss_init_sec_context", gd->gd_mech,
889 			    maj_stat, min_stat);
890 			options_ret->major_status = maj_stat;
891 			options_ret->minor_status = min_stat;
892 			break;
893 		}
894 		if (send_token.length != 0) {
895 			memset(&gr, 0, sizeof(gr));
896 
897 			bzero(&ext, sizeof(ext));
898 			ext.rc_auth = auth;
899 			call_stat = CLNT_CALL_EXT(gd->gd_clnt, &ext, NULLPROC,
900 			    (xdrproc_t)xdr_gss_buffer_desc,
901 			    &send_token,
902 			    (xdrproc_t)xdr_rpc_gss_init_res,
903 			    (caddr_t)&gr, AUTH_TIMEOUT);
904 
905 			gss_release_buffer(&min_stat, &send_token);
906 
907 			if (call_stat != RPC_SUCCESS)
908 				break;
909 
910 			if (gr.gr_major != GSS_S_COMPLETE &&
911 			    gr.gr_major != GSS_S_CONTINUE_NEEDED) {
912 				rpc_gss_log_status("server reply", gd->gd_mech,
913 				    gr.gr_major, gr.gr_minor);
914 				options_ret->major_status = gr.gr_major;
915 				options_ret->minor_status = gr.gr_minor;
916 				break;
917 			}
918 
919 			/*
920 			 * Save the server's gr_handle value, freeing
921 			 * what we have already (remember that this
922 			 * was allocated by XDR, not GSS-API).
923 			 */
924 			if (gr.gr_handle.length != 0) {
925 				xdr_free((xdrproc_t) xdr_gss_buffer_desc,
926 				    (char *) &gd->gd_cred.gc_handle);
927 				gd->gd_cred.gc_handle = gr.gr_handle;
928 			}
929 
930 			/*
931 			 * Save the server's token as well.
932 			 */
933 			if (gr.gr_token.length != 0) {
934 				recv_token = gr.gr_token;
935 				recv_tokenp = &recv_token;
936 			}
937 
938 			/*
939 			 * Since we have copied out all the bits of gr
940 			 * which XDR allocated for us, we don't need
941 			 * to free it.
942 			 */
943 			gd->gd_cred.gc_proc = RPCSEC_GSS_CONTINUE_INIT;
944 		}
945 
946 		if (maj_stat == GSS_S_COMPLETE) {
947 			gss_buffer_desc   bufin;
948 			u_int seq, qop_state = 0;
949 
950 			/*
951 			 * gss header verifier,
952 			 * usually checked in gss_validate
953 			 */
954 			seq = htonl(gr.gr_win);
955 			bufin.value = (unsigned char *)&seq;
956 			bufin.length = sizeof(seq);
957 
958 			maj_stat = gss_verify_mic(&min_stat, gd->gd_ctx,
959 			    &bufin, &gd->gd_verf, &qop_state);
960 
961 			if (maj_stat != GSS_S_COMPLETE ||
962 			    qop_state != gd->gd_qop) {
963 				rpc_gss_log_status("gss_verify_mic", gd->gd_mech,
964 				    maj_stat, min_stat);
965 				if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
966 					rpc_gss_destroy_context(auth, TRUE);
967 				}
968 				_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR,
969 				    EPERM);
970 				options_ret->major_status = maj_stat;
971 				options_ret->minor_status = min_stat;
972 				break;
973 			}
974 
975 			options_ret->major_status = GSS_S_COMPLETE;
976 			options_ret->minor_status = 0;
977 			options_ret->rpcsec_version = gd->gd_cred.gc_version;
978 			options_ret->gss_context = gd->gd_ctx;
979 
980 			gd->gd_cred.gc_proc = RPCSEC_GSS_DATA;
981 			gd->gd_seq = 1;
982 			gd->gd_win = gr.gr_win;
983 			break;
984 		}
985 	}
986 
987 	gss_release_name(&min_stat, &name);
988 	xdr_free((xdrproc_t) xdr_gss_buffer_desc,
989 	    (char *) &gd->gd_verf);
990 
991 out:
992 	/* End context negotiation loop. */
993 	if (gd->gd_cred.gc_proc != RPCSEC_GSS_DATA) {
994 		rpc_createerr.cf_stat = RPC_AUTHERROR;
995 		_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, EPERM);
996 		if (gd->gd_ctx) {
997 			gss_delete_sec_context(&min_stat, &gd->gd_ctx,
998 				GSS_C_NO_BUFFER);
999 		}
1000 		mtx_lock(&gd->gd_lock);
1001 		gd->gd_state = RPCSEC_GSS_START;
1002 		wakeup(gd);
1003 		mtx_unlock(&gd->gd_lock);
1004 		return (FALSE);
1005 	}
1006 
1007 	mtx_lock(&gd->gd_lock);
1008 	gd->gd_state = RPCSEC_GSS_ESTABLISHED;
1009 	wakeup(gd);
1010 	mtx_unlock(&gd->gd_lock);
1011 
1012 	return (TRUE);
1013 }
1014 
1015 static bool_t
1016 rpc_gss_refresh(AUTH *auth, void *msg)
1017 {
1018 	struct rpc_msg *reply = (struct rpc_msg *) msg;
1019 	rpc_gss_options_ret_t options;
1020 	struct rpc_gss_data *gd;
1021 
1022 	gd = AUTH_PRIVATE(auth);
1023 
1024 	/*
1025 	 * If the context is in DESTROYING state, then just return, since
1026 	 * there is no point in refreshing the credentials.
1027 	 */
1028 	mtx_lock(&gd->gd_lock);
1029 	if (gd->gd_state == RPCSEC_GSS_DESTROYING) {
1030 		mtx_unlock(&gd->gd_lock);
1031 		return (FALSE);
1032 	}
1033 	mtx_unlock(&gd->gd_lock);
1034 
1035 	/*
1036 	 * If the error was RPCSEC_GSS_CREDPROBLEM of
1037 	 * RPCSEC_GSS_CTXPROBLEM we start again from scratch. All
1038 	 * other errors are fatal.
1039 	 */
1040 	if (reply->rm_reply.rp_stat == MSG_DENIED
1041 	    && reply->rm_reply.rp_rjct.rj_stat == AUTH_ERROR
1042 	    && (reply->rm_reply.rp_rjct.rj_why == RPCSEC_GSS_CREDPROBLEM
1043 		|| reply->rm_reply.rp_rjct.rj_why == RPCSEC_GSS_CTXPROBLEM)) {
1044 		rpc_gss_destroy_context(auth, FALSE);
1045 		memset(&options, 0, sizeof(options));
1046 		return (rpc_gss_init(auth, &options));
1047 	}
1048 
1049 	return (FALSE);
1050 }
1051 
1052 static void
1053 rpc_gss_destroy_context(AUTH *auth, bool_t send_destroy)
1054 {
1055 	struct rpc_gss_data	*gd;
1056 	struct rpc_pending_request *pr;
1057 	OM_uint32		 min_stat;
1058 	struct rpc_callextra	 ext;
1059 
1060 	rpc_gss_log_debug("in rpc_gss_destroy_context()");
1061 
1062 	gd = AUTH_PRIVATE(auth);
1063 
1064 	mtx_lock(&gd->gd_lock);
1065 	/*
1066 	 * If the context isn't in ESTABISHED state, someone else is
1067 	 * destroying/refreshing - we wait till they are done.
1068 	 */
1069 	if (gd->gd_state != RPCSEC_GSS_ESTABLISHED) {
1070 		while (gd->gd_state != RPCSEC_GSS_START
1071 		    && gd->gd_state != RPCSEC_GSS_ESTABLISHED)
1072 			msleep(gd, &gd->gd_lock, 0, "gssstate", 0);
1073 		mtx_unlock(&gd->gd_lock);
1074 		return;
1075 	}
1076 	gd->gd_state = RPCSEC_GSS_DESTROYING;
1077 	mtx_unlock(&gd->gd_lock);
1078 
1079 	if (send_destroy) {
1080 		gd->gd_cred.gc_proc = RPCSEC_GSS_DESTROY;
1081 		bzero(&ext, sizeof(ext));
1082 		ext.rc_auth = auth;
1083 		CLNT_CALL_EXT(gd->gd_clnt, &ext, NULLPROC,
1084 		    (xdrproc_t)xdr_void, NULL,
1085 		    (xdrproc_t)xdr_void, NULL, AUTH_TIMEOUT);
1086 	}
1087 
1088 	while ((pr = LIST_FIRST(&gd->gd_reqs)) != NULL) {
1089 		LIST_REMOVE(pr, pr_link);
1090 		mem_free(pr, sizeof(*pr));
1091 	}
1092 
1093 	/*
1094 	 * Free the context token. Remember that this was
1095 	 * allocated by XDR, not GSS-API.
1096 	 */
1097 	xdr_free((xdrproc_t) xdr_gss_buffer_desc,
1098 	    (char *) &gd->gd_cred.gc_handle);
1099 	gd->gd_cred.gc_handle.length = 0;
1100 
1101 	if (gd->gd_ctx != GSS_C_NO_CONTEXT)
1102 		gss_delete_sec_context(&min_stat, &gd->gd_ctx, NULL);
1103 
1104 	mtx_lock(&gd->gd_lock);
1105 	gd->gd_state = RPCSEC_GSS_START;
1106 	wakeup(gd);
1107 	mtx_unlock(&gd->gd_lock);
1108 }
1109 
1110 static void
1111 rpc_gss_destroy(AUTH *auth)
1112 {
1113 	struct rpc_gss_data	*gd;
1114 
1115 	rpc_gss_log_debug("in rpc_gss_destroy()");
1116 
1117 	gd = AUTH_PRIVATE(auth);
1118 
1119 	if (!refcount_release(&gd->gd_refs))
1120 		return;
1121 
1122 	rpc_gss_destroy_context(auth, TRUE);
1123 
1124 	CLNT_RELEASE(gd->gd_clnt);
1125 	crfree(gd->gd_ucred);
1126 	free(gd->gd_principal, M_RPC);
1127 	if (gd->gd_clntprincipal != NULL)
1128 		free(gd->gd_clntprincipal, M_RPC);
1129 	if (gd->gd_verf.value)
1130 		xdr_free((xdrproc_t) xdr_gss_buffer_desc,
1131 		    (char *) &gd->gd_verf);
1132 	mtx_destroy(&gd->gd_lock);
1133 
1134 	mem_free(gd, sizeof(*gd));
1135 	mem_free(auth, sizeof(*auth));
1136 }
1137 
1138 int
1139 rpc_gss_max_data_length(AUTH *auth, int max_tp_unit_len)
1140 {
1141 	struct rpc_gss_data	*gd;
1142 	int			want_conf;
1143 	OM_uint32		max;
1144 	OM_uint32		maj_stat, min_stat;
1145 	int			result;
1146 
1147 	gd = AUTH_PRIVATE(auth);
1148 
1149 	switch (gd->gd_cred.gc_svc) {
1150 	case rpc_gss_svc_none:
1151 		return (max_tp_unit_len);
1152 		break;
1153 
1154 	case rpc_gss_svc_default:
1155 	case rpc_gss_svc_integrity:
1156 		want_conf = FALSE;
1157 		break;
1158 
1159 	case rpc_gss_svc_privacy:
1160 		want_conf = TRUE;
1161 		break;
1162 
1163 	default:
1164 		return (0);
1165 	}
1166 
1167 	maj_stat = gss_wrap_size_limit(&min_stat, gd->gd_ctx, want_conf,
1168 	    gd->gd_qop, max_tp_unit_len, &max);
1169 
1170 	if (maj_stat == GSS_S_COMPLETE) {
1171 		result = (int) max;
1172 		if (result < 0)
1173 			result = 0;
1174 		return (result);
1175 	} else {
1176 		rpc_gss_log_status("gss_wrap_size_limit", gd->gd_mech,
1177 		    maj_stat, min_stat);
1178 		return (0);
1179 	}
1180 }
1181