xref: /illumos-gate/usr/src/uts/common/fs/nfs/nfs_auth.c (revision dfc115332c94a2f62058ac7f2bce7631fbd20b3d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2016 Nexenta Systems, Inc.  All rights reserved.
24  * Copyright (c) 1995, 2010, Oracle and/or its affiliates. All rights reserved.
25  * Copyright (c) 2015 by Delphix. All rights reserved.
26  */
27 
28 #include <sys/param.h>
29 #include <sys/errno.h>
30 #include <sys/vfs.h>
31 #include <sys/vnode.h>
32 #include <sys/cred.h>
33 #include <sys/cmn_err.h>
34 #include <sys/systm.h>
35 #include <sys/kmem.h>
36 #include <sys/pathname.h>
37 #include <sys/utsname.h>
38 #include <sys/debug.h>
39 #include <sys/door.h>
40 #include <sys/sdt.h>
41 #include <sys/thread.h>
42 #include <sys/avl.h>
43 
44 #include <rpc/types.h>
45 #include <rpc/auth.h>
46 #include <rpc/clnt.h>
47 
48 #include <nfs/nfs.h>
49 #include <nfs/export.h>
50 #include <nfs/nfs_clnt.h>
51 #include <nfs/auth.h>
52 
53 static struct kmem_cache *exi_cache_handle;
54 static void exi_cache_reclaim(void *);
55 static void exi_cache_trim(struct exportinfo *exi);
56 
57 extern pri_t minclsyspri;
58 
59 volatile uint_t nfsauth_cache_hit;
60 volatile uint_t nfsauth_cache_miss;
61 volatile uint_t nfsauth_cache_refresh;
62 volatile uint_t nfsauth_cache_reclaim;
63 volatile uint_t exi_cache_auth_reclaim_failed;
64 volatile uint_t exi_cache_clnt_reclaim_failed;
65 
66 /*
67  * The lifetime of an auth cache entry:
68  * ------------------------------------
69  *
70  * An auth cache entry is created with both the auth_time
71  * and auth_freshness times set to the current time.
72  *
73  * Upon every client access which results in a hit, the
74  * auth_time will be updated.
75  *
76  * If a client access determines that the auth_freshness
77  * indicates that the entry is STALE, then it will be
78  * refreshed. Note that this will explicitly reset
79  * auth_time.
80  *
81  * When the REFRESH successfully occurs, then the
82  * auth_freshness is updated.
83  *
84  * There are two ways for an entry to leave the cache:
85  *
86  * 1) Purged by an action on the export (remove or changed)
87  * 2) Memory backpressure from the kernel (check against NFSAUTH_CACHE_TRIM)
88  *
89  * For 2) we check the timeout value against auth_time.
90  */
91 
92 /*
93  * Number of seconds until we mark for refresh an auth cache entry.
94  */
95 #define	NFSAUTH_CACHE_REFRESH 600
96 
97 /*
98  * Number of idle seconds until we yield to backpressure
99  * to trim a cache entry.
100  */
101 #define	NFSAUTH_CACHE_TRIM 3600
102 
103 /*
104  * While we could encapuslate the exi_list inside the
105  * exi structure, we can't do that for the auth_list.
106  * So, to keep things looking clean, we keep them both
107  * in these external lists.
108  */
109 typedef struct refreshq_exi_node {
110 	struct exportinfo	*ren_exi;
111 	list_t			ren_authlist;
112 	list_node_t		ren_node;
113 } refreshq_exi_node_t;
114 
115 typedef struct refreshq_auth_node {
116 	struct auth_cache	*ran_auth;
117 	char			*ran_netid;
118 	list_node_t		ran_node;
119 } refreshq_auth_node_t;
120 
121 /*
122  * Used to manipulate things on the refreshq_queue.
123  * Note that the refresh thread will effectively
124  * pop a node off of the queue, at which point it
125  * will no longer need to hold the mutex.
126  */
127 static kmutex_t refreshq_lock;
128 static list_t refreshq_queue;
129 static kcondvar_t refreshq_cv;
130 
131 /*
132  * If there is ever a problem with loading the
133  * module, then nfsauth_fini() needs to be called
134  * to remove state. In that event, since the
135  * refreshq thread has been started, they need to
136  * work together to get rid of state.
137  */
138 typedef enum nfsauth_refreshq_thread_state {
139 	REFRESHQ_THREAD_RUNNING,
140 	REFRESHQ_THREAD_FINI_REQ,
141 	REFRESHQ_THREAD_HALTED
142 } nfsauth_refreshq_thread_state_t;
143 
144 nfsauth_refreshq_thread_state_t
145 refreshq_thread_state = REFRESHQ_THREAD_HALTED;
146 
147 static void nfsauth_free_node(struct auth_cache *);
148 static void nfsauth_refresh_thread(void);
149 
150 static int nfsauth_cache_compar(const void *, const void *);
151 
152 /*
153  * mountd is a server-side only daemon. This will need to be
154  * revisited if the NFS server is ever made zones-aware.
155  */
156 kmutex_t	mountd_lock;
157 door_handle_t   mountd_dh;
158 
159 void
160 mountd_args(uint_t did)
161 {
162 	mutex_enter(&mountd_lock);
163 	if (mountd_dh != NULL)
164 		door_ki_rele(mountd_dh);
165 	mountd_dh = door_ki_lookup(did);
166 	mutex_exit(&mountd_lock);
167 }
168 
169 void
170 nfsauth_init(void)
171 {
172 	/*
173 	 * mountd can be restarted by smf(5). We need to make sure
174 	 * the updated door handle will safely make it to mountd_dh
175 	 */
176 	mutex_init(&mountd_lock, NULL, MUTEX_DEFAULT, NULL);
177 
178 	mutex_init(&refreshq_lock, NULL, MUTEX_DEFAULT, NULL);
179 	list_create(&refreshq_queue, sizeof (refreshq_exi_node_t),
180 	    offsetof(refreshq_exi_node_t, ren_node));
181 
182 	cv_init(&refreshq_cv, NULL, CV_DEFAULT, NULL);
183 
184 	/*
185 	 * Allocate nfsauth cache handle
186 	 */
187 	exi_cache_handle = kmem_cache_create("exi_cache_handle",
188 	    sizeof (struct auth_cache), 0, NULL, NULL,
189 	    exi_cache_reclaim, NULL, NULL, 0);
190 
191 	refreshq_thread_state = REFRESHQ_THREAD_RUNNING;
192 	(void) zthread_create(NULL, 0, nfsauth_refresh_thread,
193 	    NULL, 0, minclsyspri);
194 }
195 
196 /*
197  * Finalization routine for nfsauth. It is important to call this routine
198  * before destroying the exported_lock.
199  */
200 void
201 nfsauth_fini(void)
202 {
203 	refreshq_exi_node_t	*ren;
204 
205 	/*
206 	 * Prevent the nfsauth_refresh_thread from getting new
207 	 * work.
208 	 */
209 	mutex_enter(&refreshq_lock);
210 	if (refreshq_thread_state != REFRESHQ_THREAD_HALTED) {
211 		refreshq_thread_state = REFRESHQ_THREAD_FINI_REQ;
212 		cv_broadcast(&refreshq_cv);
213 
214 		/*
215 		 * Also, wait for nfsauth_refresh_thread() to exit.
216 		 */
217 		while (refreshq_thread_state != REFRESHQ_THREAD_HALTED) {
218 			cv_wait(&refreshq_cv, &refreshq_lock);
219 		}
220 	}
221 	mutex_exit(&refreshq_lock);
222 
223 	/*
224 	 * Walk the exi_list and in turn, walk the auth_lists and free all
225 	 * lists.  In addition, free INVALID auth_cache entries.
226 	 */
227 	while ((ren = list_remove_head(&refreshq_queue))) {
228 		refreshq_auth_node_t *ran;
229 
230 		while ((ran = list_remove_head(&ren->ren_authlist)) != NULL) {
231 			struct auth_cache *p = ran->ran_auth;
232 			if (p->auth_state == NFS_AUTH_INVALID)
233 				nfsauth_free_node(p);
234 			strfree(ran->ran_netid);
235 			kmem_free(ran, sizeof (refreshq_auth_node_t));
236 		}
237 
238 		list_destroy(&ren->ren_authlist);
239 		exi_rele(ren->ren_exi);
240 		kmem_free(ren, sizeof (refreshq_exi_node_t));
241 	}
242 	list_destroy(&refreshq_queue);
243 
244 	cv_destroy(&refreshq_cv);
245 	mutex_destroy(&refreshq_lock);
246 
247 	mutex_destroy(&mountd_lock);
248 
249 	/*
250 	 * Deallocate nfsauth cache handle
251 	 */
252 	kmem_cache_destroy(exi_cache_handle);
253 }
254 
255 /*
256  * Convert the address in a netbuf to
257  * a hash index for the auth_cache table.
258  */
259 static int
260 hash(struct netbuf *a)
261 {
262 	int i, h = 0;
263 
264 	for (i = 0; i < a->len; i++)
265 		h ^= a->buf[i];
266 
267 	return (h & (AUTH_TABLESIZE - 1));
268 }
269 
270 /*
271  * Mask out the components of an
272  * address that do not identify
273  * a host. For socket addresses the
274  * masking gets rid of the port number.
275  */
276 static void
277 addrmask(struct netbuf *addr, struct netbuf *mask)
278 {
279 	int i;
280 
281 	for (i = 0; i < addr->len; i++)
282 		addr->buf[i] &= mask->buf[i];
283 }
284 
285 /*
286  * nfsauth4_access is used for NFS V4 auth checking. Besides doing
287  * the common nfsauth_access(), it will check if the client can
288  * have a limited access to this vnode even if the security flavor
289  * used does not meet the policy.
290  */
291 int
292 nfsauth4_access(struct exportinfo *exi, vnode_t *vp, struct svc_req *req,
293     cred_t *cr, uid_t *uid, gid_t *gid, uint_t *ngids, gid_t **gids)
294 {
295 	int access;
296 
297 	access = nfsauth_access(exi, req, cr, uid, gid, ngids, gids);
298 
299 	/*
300 	 * There are cases that the server needs to allow the client
301 	 * to have a limited view.
302 	 *
303 	 * e.g.
304 	 * /export is shared as "sec=sys,rw=dfs-test-4,sec=krb5,rw"
305 	 * /export/home is shared as "sec=sys,rw"
306 	 *
307 	 * When the client mounts /export with sec=sys, the client
308 	 * would get a limited view with RO access on /export to see
309 	 * "home" only because the client is allowed to access
310 	 * /export/home with auth_sys.
311 	 */
312 	if (access & NFSAUTH_DENIED || access & NFSAUTH_WRONGSEC) {
313 		/*
314 		 * Allow ro permission with LIMITED view if there is a
315 		 * sub-dir exported under vp.
316 		 */
317 		if (has_visible(exi, vp))
318 			return (NFSAUTH_LIMITED);
319 	}
320 
321 	return (access);
322 }
323 
324 static void
325 sys_log(const char *msg)
326 {
327 	static time_t	tstamp = 0;
328 	time_t		now;
329 
330 	/*
331 	 * msg is shown (at most) once per minute
332 	 */
333 	now = gethrestime_sec();
334 	if ((tstamp + 60) < now) {
335 		tstamp = now;
336 		cmn_err(CE_WARN, msg);
337 	}
338 }
339 
340 /*
341  * Callup to the mountd to get access information in the kernel.
342  */
343 static bool_t
344 nfsauth_retrieve(struct exportinfo *exi, char *req_netid, int flavor,
345     struct netbuf *addr, int *access, cred_t *clnt_cred, uid_t *srv_uid,
346     gid_t *srv_gid, uint_t *srv_gids_cnt, gid_t **srv_gids)
347 {
348 	varg_t			  varg = {0};
349 	nfsauth_res_t		  res = {0};
350 	XDR			  xdrs;
351 	size_t			  absz;
352 	caddr_t			  abuf;
353 	int			  last = 0;
354 	door_arg_t		  da;
355 	door_info_t		  di;
356 	door_handle_t		  dh;
357 	uint_t			  ntries = 0;
358 
359 	/*
360 	 * No entry in the cache for this client/flavor
361 	 * so we need to call the nfsauth service in the
362 	 * mount daemon.
363 	 */
364 
365 	varg.vers = V_PROTO;
366 	varg.arg_u.arg.cmd = NFSAUTH_ACCESS;
367 	varg.arg_u.arg.areq.req_client.n_len = addr->len;
368 	varg.arg_u.arg.areq.req_client.n_bytes = addr->buf;
369 	varg.arg_u.arg.areq.req_netid = req_netid;
370 	varg.arg_u.arg.areq.req_path = exi->exi_export.ex_path;
371 	varg.arg_u.arg.areq.req_flavor = flavor;
372 	varg.arg_u.arg.areq.req_clnt_uid = crgetuid(clnt_cred);
373 	varg.arg_u.arg.areq.req_clnt_gid = crgetgid(clnt_cred);
374 	varg.arg_u.arg.areq.req_clnt_gids.len = crgetngroups(clnt_cred);
375 	varg.arg_u.arg.areq.req_clnt_gids.val = (gid_t *)crgetgroups(clnt_cred);
376 
377 	DTRACE_PROBE1(nfsserv__func__nfsauth__varg, varg_t *, &varg);
378 
379 	/*
380 	 * Setup the XDR stream for encoding the arguments. Notice that
381 	 * in addition to the args having variable fields (req_netid and
382 	 * req_path), the argument data structure is itself versioned,
383 	 * so we need to make sure we can size the arguments buffer
384 	 * appropriately to encode all the args. If we can't get sizing
385 	 * info _or_ properly encode the arguments, there's really no
386 	 * point in continuting, so we fail the request.
387 	 */
388 	if ((absz = xdr_sizeof(xdr_varg, &varg)) == 0) {
389 		*access = NFSAUTH_DENIED;
390 		return (FALSE);
391 	}
392 
393 	abuf = (caddr_t)kmem_alloc(absz, KM_SLEEP);
394 	xdrmem_create(&xdrs, abuf, absz, XDR_ENCODE);
395 	if (!xdr_varg(&xdrs, &varg)) {
396 		XDR_DESTROY(&xdrs);
397 		goto fail;
398 	}
399 	XDR_DESTROY(&xdrs);
400 
401 	/*
402 	 * Prepare the door arguments
403 	 *
404 	 * We don't know the size of the message the daemon
405 	 * will pass back to us.  By setting rbuf to NULL,
406 	 * we force the door code to allocate a buf of the
407 	 * appropriate size.  We must set rsize > 0, however,
408 	 * else the door code acts as if no response was
409 	 * expected and doesn't pass the data to us.
410 	 */
411 	da.data_ptr = (char *)abuf;
412 	da.data_size = absz;
413 	da.desc_ptr = NULL;
414 	da.desc_num = 0;
415 	da.rbuf = NULL;
416 	da.rsize = 1;
417 
418 retry:
419 	mutex_enter(&mountd_lock);
420 	dh = mountd_dh;
421 	if (dh != NULL)
422 		door_ki_hold(dh);
423 	mutex_exit(&mountd_lock);
424 
425 	if (dh == NULL) {
426 		/*
427 		 * The rendezvous point has not been established yet!
428 		 * This could mean that either mountd(1m) has not yet
429 		 * been started or that _this_ routine nuked the door
430 		 * handle after receiving an EINTR for a REVOKED door.
431 		 *
432 		 * Returning NFSAUTH_DROP will cause the NFS client
433 		 * to retransmit the request, so let's try to be more
434 		 * rescillient and attempt for ntries before we bail.
435 		 */
436 		if (++ntries % NFSAUTH_DR_TRYCNT) {
437 			delay(hz);
438 			goto retry;
439 		}
440 
441 		kmem_free(abuf, absz);
442 
443 		sys_log("nfsauth: mountd has not established door");
444 		*access = NFSAUTH_DROP;
445 		return (FALSE);
446 	}
447 
448 	ntries = 0;
449 
450 	/*
451 	 * Now that we've got what we need, place the call.
452 	 */
453 	switch (door_ki_upcall_limited(dh, &da, NULL, SIZE_MAX, 0)) {
454 	case 0:				/* Success */
455 		door_ki_rele(dh);
456 
457 		if (da.data_ptr == NULL && da.data_size == 0) {
458 			/*
459 			 * The door_return that contained the data
460 			 * failed! We're here because of the 2nd
461 			 * door_return (w/o data) such that we can
462 			 * get control of the thread (and exit
463 			 * gracefully).
464 			 */
465 			DTRACE_PROBE1(nfsserv__func__nfsauth__door__nil,
466 			    door_arg_t *, &da);
467 			goto fail;
468 		}
469 
470 		break;
471 
472 	case EAGAIN:
473 		/*
474 		 * Server out of resources; back off for a bit
475 		 */
476 		door_ki_rele(dh);
477 		delay(hz);
478 		goto retry;
479 		/* NOTREACHED */
480 
481 	case EINTR:
482 		if (!door_ki_info(dh, &di)) {
483 			door_ki_rele(dh);
484 
485 			if (di.di_attributes & DOOR_REVOKED) {
486 				/*
487 				 * The server barfed and revoked
488 				 * the (existing) door on us; we
489 				 * want to wait to give smf(5) a
490 				 * chance to restart mountd(1m)
491 				 * and establish a new door handle.
492 				 */
493 				mutex_enter(&mountd_lock);
494 				if (dh == mountd_dh) {
495 					door_ki_rele(mountd_dh);
496 					mountd_dh = NULL;
497 				}
498 				mutex_exit(&mountd_lock);
499 				delay(hz);
500 				goto retry;
501 			}
502 			/*
503 			 * If the door was _not_ revoked on us,
504 			 * then more than likely we took an INTR,
505 			 * so we need to fail the operation.
506 			 */
507 			goto fail;
508 		}
509 		/*
510 		 * The only failure that can occur from getting
511 		 * the door info is EINVAL, so we let the code
512 		 * below handle it.
513 		 */
514 		/* FALLTHROUGH */
515 
516 	case EBADF:
517 	case EINVAL:
518 	default:
519 		/*
520 		 * If we have a stale door handle, give smf a last
521 		 * chance to start it by sleeping for a little bit.
522 		 * If we're still hosed, we'll fail the call.
523 		 *
524 		 * Since we're going to reacquire the door handle
525 		 * upon the retry, we opt to sleep for a bit and
526 		 * _not_ to clear mountd_dh. If mountd restarted
527 		 * and was able to set mountd_dh, we should see
528 		 * the new instance; if not, we won't get caught
529 		 * up in the retry/DELAY loop.
530 		 */
531 		door_ki_rele(dh);
532 		if (!last) {
533 			delay(hz);
534 			last++;
535 			goto retry;
536 		}
537 		sys_log("nfsauth: stale mountd door handle");
538 		goto fail;
539 	}
540 
541 	ASSERT(da.rbuf != NULL);
542 
543 	/*
544 	 * No door errors encountered; setup the XDR stream for decoding
545 	 * the results. If we fail to decode the results, we've got no
546 	 * other recourse than to fail the request.
547 	 */
548 	xdrmem_create(&xdrs, da.rbuf, da.rsize, XDR_DECODE);
549 	if (!xdr_nfsauth_res(&xdrs, &res)) {
550 		xdr_free(xdr_nfsauth_res, (char *)&res);
551 		XDR_DESTROY(&xdrs);
552 		kmem_free(da.rbuf, da.rsize);
553 		goto fail;
554 	}
555 	XDR_DESTROY(&xdrs);
556 	kmem_free(da.rbuf, da.rsize);
557 
558 	DTRACE_PROBE1(nfsserv__func__nfsauth__results, nfsauth_res_t *, &res);
559 	switch (res.stat) {
560 		case NFSAUTH_DR_OKAY:
561 			*access = res.ares.auth_perm;
562 			*srv_uid = res.ares.auth_srv_uid;
563 			*srv_gid = res.ares.auth_srv_gid;
564 			*srv_gids_cnt = res.ares.auth_srv_gids.len;
565 			*srv_gids = kmem_alloc(*srv_gids_cnt * sizeof (gid_t),
566 			    KM_SLEEP);
567 			bcopy(res.ares.auth_srv_gids.val, *srv_gids,
568 			    *srv_gids_cnt * sizeof (gid_t));
569 			break;
570 
571 		case NFSAUTH_DR_EFAIL:
572 		case NFSAUTH_DR_DECERR:
573 		case NFSAUTH_DR_BADCMD:
574 		default:
575 			xdr_free(xdr_nfsauth_res, (char *)&res);
576 fail:
577 			*access = NFSAUTH_DENIED;
578 			kmem_free(abuf, absz);
579 			return (FALSE);
580 			/* NOTREACHED */
581 	}
582 
583 	xdr_free(xdr_nfsauth_res, (char *)&res);
584 	kmem_free(abuf, absz);
585 
586 	return (TRUE);
587 }
588 
589 static void
590 nfsauth_refresh_thread(void)
591 {
592 	refreshq_exi_node_t	*ren;
593 	refreshq_auth_node_t	*ran;
594 
595 	struct exportinfo	*exi;
596 
597 	int			access;
598 	bool_t			retrieval;
599 
600 	callb_cpr_t		cprinfo;
601 
602 	CALLB_CPR_INIT(&cprinfo, &refreshq_lock, callb_generic_cpr,
603 	    "nfsauth_refresh");
604 
605 	for (;;) {
606 		mutex_enter(&refreshq_lock);
607 		if (refreshq_thread_state != REFRESHQ_THREAD_RUNNING) {
608 			/* Keep the hold on the lock! */
609 			break;
610 		}
611 
612 		ren = list_remove_head(&refreshq_queue);
613 		if (ren == NULL) {
614 			CALLB_CPR_SAFE_BEGIN(&cprinfo);
615 			cv_wait(&refreshq_cv, &refreshq_lock);
616 			CALLB_CPR_SAFE_END(&cprinfo, &refreshq_lock);
617 			mutex_exit(&refreshq_lock);
618 			continue;
619 		}
620 		mutex_exit(&refreshq_lock);
621 
622 		exi = ren->ren_exi;
623 		ASSERT(exi != NULL);
624 
625 		/*
626 		 * Since the ren was removed from the refreshq_queue above,
627 		 * this is the only thread aware about the ren existence, so we
628 		 * have the exclusive ownership of it and we do not need to
629 		 * protect it by any lock.
630 		 */
631 		while ((ran = list_remove_head(&ren->ren_authlist))) {
632 			uid_t uid;
633 			gid_t gid;
634 			uint_t ngids;
635 			gid_t *gids;
636 			struct auth_cache *p = ran->ran_auth;
637 			char *netid = ran->ran_netid;
638 
639 			ASSERT(p != NULL);
640 			ASSERT(netid != NULL);
641 
642 			kmem_free(ran, sizeof (refreshq_auth_node_t));
643 
644 			mutex_enter(&p->auth_lock);
645 
646 			/*
647 			 * Once the entry goes INVALID, it can not change
648 			 * state.
649 			 *
650 			 * No need to refresh entries also in a case we are
651 			 * just shutting down.
652 			 *
653 			 * In general, there is no need to hold the
654 			 * refreshq_lock to test the refreshq_thread_state.  We
655 			 * do hold it at other places because there is some
656 			 * related thread synchronization (or some other tasks)
657 			 * close to the refreshq_thread_state check.
658 			 *
659 			 * The check for the refreshq_thread_state value here
660 			 * is purely advisory to allow the faster
661 			 * nfsauth_refresh_thread() shutdown.  In a case we
662 			 * will miss such advisory, nothing catastrophic
663 			 * happens: we will just spin longer here before the
664 			 * shutdown.
665 			 */
666 			if (p->auth_state == NFS_AUTH_INVALID ||
667 			    refreshq_thread_state != REFRESHQ_THREAD_RUNNING) {
668 				mutex_exit(&p->auth_lock);
669 
670 				if (p->auth_state == NFS_AUTH_INVALID)
671 					nfsauth_free_node(p);
672 
673 				strfree(netid);
674 
675 				continue;
676 			}
677 
678 			/*
679 			 * Make sure the state is valid.  Note that once we
680 			 * change the state to NFS_AUTH_REFRESHING, no other
681 			 * thread will be able to work on this entry.
682 			 */
683 			ASSERT(p->auth_state == NFS_AUTH_STALE);
684 
685 			p->auth_state = NFS_AUTH_REFRESHING;
686 			mutex_exit(&p->auth_lock);
687 
688 			DTRACE_PROBE2(nfsauth__debug__cache__refresh,
689 			    struct exportinfo *, exi,
690 			    struct auth_cache *, p);
691 
692 			/*
693 			 * The first caching of the access rights
694 			 * is done with the netid pulled out of the
695 			 * request from the client. All subsequent
696 			 * users of the cache may or may not have
697 			 * the same netid. It doesn't matter. So
698 			 * when we refresh, we simply use the netid
699 			 * of the request which triggered the
700 			 * refresh attempt.
701 			 */
702 			retrieval = nfsauth_retrieve(exi, netid,
703 			    p->auth_flavor, &p->auth_clnt->authc_addr, &access,
704 			    p->auth_clnt_cred, &uid, &gid, &ngids, &gids);
705 
706 			/*
707 			 * This can only be set in one other place
708 			 * and the state has to be NFS_AUTH_FRESH.
709 			 */
710 			strfree(netid);
711 
712 			mutex_enter(&p->auth_lock);
713 			if (p->auth_state == NFS_AUTH_INVALID) {
714 				mutex_exit(&p->auth_lock);
715 				nfsauth_free_node(p);
716 				if (retrieval == TRUE)
717 					kmem_free(gids, ngids * sizeof (gid_t));
718 			} else {
719 				/*
720 				 * If we got an error, do not reset the
721 				 * time. This will cause the next access
722 				 * check for the client to reschedule this
723 				 * node.
724 				 */
725 				if (retrieval == TRUE) {
726 					p->auth_access = access;
727 
728 					p->auth_srv_uid = uid;
729 					p->auth_srv_gid = gid;
730 					kmem_free(p->auth_srv_gids,
731 					    p->auth_srv_ngids * sizeof (gid_t));
732 					p->auth_srv_ngids = ngids;
733 					p->auth_srv_gids = gids;
734 
735 					p->auth_freshness = gethrestime_sec();
736 				}
737 				p->auth_state = NFS_AUTH_FRESH;
738 
739 				cv_broadcast(&p->auth_cv);
740 				mutex_exit(&p->auth_lock);
741 			}
742 		}
743 
744 		list_destroy(&ren->ren_authlist);
745 		exi_rele(ren->ren_exi);
746 		kmem_free(ren, sizeof (refreshq_exi_node_t));
747 	}
748 
749 	refreshq_thread_state = REFRESHQ_THREAD_HALTED;
750 	cv_broadcast(&refreshq_cv);
751 	CALLB_CPR_EXIT(&cprinfo);
752 	zthread_exit();
753 }
754 
755 int
756 nfsauth_cache_clnt_compar(const void *v1, const void *v2)
757 {
758 	int c;
759 
760 	const struct auth_cache_clnt *a1 = (const struct auth_cache_clnt *)v1;
761 	const struct auth_cache_clnt *a2 = (const struct auth_cache_clnt *)v2;
762 
763 	if (a1->authc_addr.len < a2->authc_addr.len)
764 		return (-1);
765 	if (a1->authc_addr.len > a2->authc_addr.len)
766 		return (1);
767 
768 	c = memcmp(a1->authc_addr.buf, a2->authc_addr.buf, a1->authc_addr.len);
769 	if (c < 0)
770 		return (-1);
771 	if (c > 0)
772 		return (1);
773 
774 	return (0);
775 }
776 
777 static int
778 nfsauth_cache_compar(const void *v1, const void *v2)
779 {
780 	int c;
781 
782 	const struct auth_cache *a1 = (const struct auth_cache *)v1;
783 	const struct auth_cache *a2 = (const struct auth_cache *)v2;
784 
785 	if (a1->auth_flavor < a2->auth_flavor)
786 		return (-1);
787 	if (a1->auth_flavor > a2->auth_flavor)
788 		return (1);
789 
790 	if (crgetuid(a1->auth_clnt_cred) < crgetuid(a2->auth_clnt_cred))
791 		return (-1);
792 	if (crgetuid(a1->auth_clnt_cred) > crgetuid(a2->auth_clnt_cred))
793 		return (1);
794 
795 	if (crgetgid(a1->auth_clnt_cred) < crgetgid(a2->auth_clnt_cred))
796 		return (-1);
797 	if (crgetgid(a1->auth_clnt_cred) > crgetgid(a2->auth_clnt_cred))
798 		return (1);
799 
800 	if (crgetngroups(a1->auth_clnt_cred) < crgetngroups(a2->auth_clnt_cred))
801 		return (-1);
802 	if (crgetngroups(a1->auth_clnt_cred) > crgetngroups(a2->auth_clnt_cred))
803 		return (1);
804 
805 	c = memcmp(crgetgroups(a1->auth_clnt_cred),
806 	    crgetgroups(a2->auth_clnt_cred), crgetngroups(a1->auth_clnt_cred));
807 	if (c < 0)
808 		return (-1);
809 	if (c > 0)
810 		return (1);
811 
812 	return (0);
813 }
814 
815 /*
816  * Get the access information from the cache or callup to the mountd
817  * to get and cache the access information in the kernel.
818  */
819 static int
820 nfsauth_cache_get(struct exportinfo *exi, struct svc_req *req, int flavor,
821     cred_t *cr, uid_t *uid, gid_t *gid, uint_t *ngids, gid_t **gids)
822 {
823 	struct netbuf		*taddrmask;
824 	struct netbuf		addr;	/* temporary copy of client's address */
825 	const struct netbuf	*claddr;
826 	avl_tree_t		*tree;
827 	struct auth_cache	ac;	/* used as a template for avl_find() */
828 	struct auth_cache_clnt	*c;
829 	struct auth_cache_clnt	acc;	/* used as a template for avl_find() */
830 	struct auth_cache	*p = NULL;
831 	int			access;
832 
833 	uid_t			tmpuid;
834 	gid_t			tmpgid;
835 	uint_t			tmpngids;
836 	gid_t			*tmpgids;
837 
838 	avl_index_t		where;	/* used for avl_find()/avl_insert() */
839 
840 	ASSERT(cr != NULL);
841 
842 	/*
843 	 * Now check whether this client already
844 	 * has an entry for this flavor in the cache
845 	 * for this export.
846 	 * Get the caller's address, mask off the
847 	 * parts of the address that do not identify
848 	 * the host (port number, etc), and then hash
849 	 * it to find the chain of cache entries.
850 	 */
851 
852 	claddr = svc_getrpccaller(req->rq_xprt);
853 	addr = *claddr;
854 	addr.buf = kmem_alloc(addr.maxlen, KM_SLEEP);
855 	bcopy(claddr->buf, addr.buf, claddr->len);
856 
857 	SVC_GETADDRMASK(req->rq_xprt, SVC_TATTR_ADDRMASK, (void **)&taddrmask);
858 	ASSERT(taddrmask != NULL);
859 	addrmask(&addr, taddrmask);
860 
861 	ac.auth_flavor = flavor;
862 	ac.auth_clnt_cred = crdup(cr);
863 
864 	acc.authc_addr = addr;
865 
866 	tree = exi->exi_cache[hash(&addr)];
867 
868 	rw_enter(&exi->exi_cache_lock, RW_READER);
869 	c = (struct auth_cache_clnt *)avl_find(tree, &acc, NULL);
870 
871 	if (c == NULL) {
872 		struct auth_cache_clnt *nc;
873 
874 		rw_exit(&exi->exi_cache_lock);
875 
876 		nc = kmem_alloc(sizeof (*nc), KM_NOSLEEP | KM_NORMALPRI);
877 		if (nc == NULL)
878 			goto retrieve;
879 
880 		/*
881 		 * Initialize the new auth_cache_clnt
882 		 */
883 		nc->authc_addr = addr;
884 		nc->authc_addr.buf = kmem_alloc(addr.maxlen,
885 		    KM_NOSLEEP | KM_NORMALPRI);
886 		if (addr.maxlen != 0 && nc->authc_addr.buf == NULL) {
887 			kmem_free(nc, sizeof (*nc));
888 			goto retrieve;
889 		}
890 		bcopy(addr.buf, nc->authc_addr.buf, addr.len);
891 		rw_init(&nc->authc_lock, NULL, RW_DEFAULT, NULL);
892 		avl_create(&nc->authc_tree, nfsauth_cache_compar,
893 		    sizeof (struct auth_cache),
894 		    offsetof(struct auth_cache, auth_link));
895 
896 		rw_enter(&exi->exi_cache_lock, RW_WRITER);
897 		c = (struct auth_cache_clnt *)avl_find(tree, &acc, &where);
898 		if (c == NULL) {
899 			avl_insert(tree, nc, where);
900 			rw_downgrade(&exi->exi_cache_lock);
901 			c = nc;
902 		} else {
903 			rw_downgrade(&exi->exi_cache_lock);
904 
905 			avl_destroy(&nc->authc_tree);
906 			rw_destroy(&nc->authc_lock);
907 			kmem_free(nc->authc_addr.buf, nc->authc_addr.maxlen);
908 			kmem_free(nc, sizeof (*nc));
909 		}
910 	}
911 
912 	ASSERT(c != NULL);
913 
914 	rw_enter(&c->authc_lock, RW_READER);
915 	p = (struct auth_cache *)avl_find(&c->authc_tree, &ac, NULL);
916 
917 	if (p == NULL) {
918 		struct auth_cache *np;
919 
920 		rw_exit(&c->authc_lock);
921 
922 		np = kmem_cache_alloc(exi_cache_handle,
923 		    KM_NOSLEEP | KM_NORMALPRI);
924 		if (np == NULL) {
925 			rw_exit(&exi->exi_cache_lock);
926 			goto retrieve;
927 		}
928 
929 		/*
930 		 * Initialize the new auth_cache
931 		 */
932 		np->auth_clnt = c;
933 		np->auth_flavor = flavor;
934 		np->auth_clnt_cred = ac.auth_clnt_cred;
935 		np->auth_srv_ngids = 0;
936 		np->auth_srv_gids = NULL;
937 		np->auth_time = np->auth_freshness = gethrestime_sec();
938 		np->auth_state = NFS_AUTH_NEW;
939 		mutex_init(&np->auth_lock, NULL, MUTEX_DEFAULT, NULL);
940 		cv_init(&np->auth_cv, NULL, CV_DEFAULT, NULL);
941 
942 		rw_enter(&c->authc_lock, RW_WRITER);
943 		rw_exit(&exi->exi_cache_lock);
944 
945 		p = (struct auth_cache *)avl_find(&c->authc_tree, &ac, &where);
946 		if (p == NULL) {
947 			avl_insert(&c->authc_tree, np, where);
948 			rw_downgrade(&c->authc_lock);
949 			p = np;
950 		} else {
951 			rw_downgrade(&c->authc_lock);
952 
953 			cv_destroy(&np->auth_cv);
954 			mutex_destroy(&np->auth_lock);
955 			crfree(ac.auth_clnt_cred);
956 			kmem_cache_free(exi_cache_handle, np);
957 		}
958 	} else {
959 		rw_exit(&exi->exi_cache_lock);
960 		crfree(ac.auth_clnt_cred);
961 	}
962 
963 	mutex_enter(&p->auth_lock);
964 	rw_exit(&c->authc_lock);
965 
966 	/*
967 	 * If the entry is in the WAITING state then some other thread is just
968 	 * retrieving the required info.  The entry was either NEW, or the list
969 	 * of client's supplemental groups is going to be changed (either by
970 	 * this thread, or by some other thread).  We need to wait until the
971 	 * nfsauth_retrieve() is done.
972 	 */
973 	while (p->auth_state == NFS_AUTH_WAITING)
974 		cv_wait(&p->auth_cv, &p->auth_lock);
975 
976 	/*
977 	 * Here the entry cannot be in WAITING or INVALID state.
978 	 */
979 	ASSERT(p->auth_state != NFS_AUTH_WAITING);
980 	ASSERT(p->auth_state != NFS_AUTH_INVALID);
981 
982 	/*
983 	 * If the cache entry is not valid yet, we need to retrieve the
984 	 * info ourselves.
985 	 */
986 	if (p->auth_state == NFS_AUTH_NEW) {
987 		bool_t res;
988 		/*
989 		 * NFS_AUTH_NEW is the default output auth_state value in a
990 		 * case we failed somewhere below.
991 		 */
992 		auth_state_t state = NFS_AUTH_NEW;
993 
994 		p->auth_state = NFS_AUTH_WAITING;
995 		mutex_exit(&p->auth_lock);
996 		kmem_free(addr.buf, addr.maxlen);
997 		addr = p->auth_clnt->authc_addr;
998 
999 		atomic_inc_uint(&nfsauth_cache_miss);
1000 
1001 		res = nfsauth_retrieve(exi, svc_getnetid(req->rq_xprt), flavor,
1002 		    &addr, &access, cr, &tmpuid, &tmpgid, &tmpngids, &tmpgids);
1003 
1004 		p->auth_access = access;
1005 		p->auth_time = p->auth_freshness = gethrestime_sec();
1006 
1007 		if (res == TRUE) {
1008 			if (uid != NULL)
1009 				*uid = tmpuid;
1010 			if (gid != NULL)
1011 				*gid = tmpgid;
1012 			if (ngids != NULL && gids != NULL) {
1013 				*ngids = tmpngids;
1014 				*gids = tmpgids;
1015 
1016 				/*
1017 				 * We need a copy of gids for the
1018 				 * auth_cache entry
1019 				 */
1020 				tmpgids = kmem_alloc(tmpngids * sizeof (gid_t),
1021 				    KM_NOSLEEP | KM_NORMALPRI);
1022 				if (tmpgids != NULL)
1023 					bcopy(*gids, tmpgids,
1024 					    tmpngids * sizeof (gid_t));
1025 			}
1026 
1027 			if (tmpgids != NULL || tmpngids == 0) {
1028 				p->auth_srv_uid = tmpuid;
1029 				p->auth_srv_gid = tmpgid;
1030 				p->auth_srv_ngids = tmpngids;
1031 				p->auth_srv_gids = tmpgids;
1032 
1033 				state = NFS_AUTH_FRESH;
1034 			}
1035 		}
1036 
1037 		/*
1038 		 * Set the auth_state and notify waiters.
1039 		 */
1040 		mutex_enter(&p->auth_lock);
1041 		p->auth_state = state;
1042 		cv_broadcast(&p->auth_cv);
1043 		mutex_exit(&p->auth_lock);
1044 	} else {
1045 		uint_t nach;
1046 		time_t refresh;
1047 
1048 		refresh = gethrestime_sec() - p->auth_freshness;
1049 
1050 		p->auth_time = gethrestime_sec();
1051 
1052 		if (uid != NULL)
1053 			*uid = p->auth_srv_uid;
1054 		if (gid != NULL)
1055 			*gid = p->auth_srv_gid;
1056 		if (ngids != NULL && gids != NULL) {
1057 			*ngids = p->auth_srv_ngids;
1058 			*gids = kmem_alloc(*ngids * sizeof (gid_t), KM_SLEEP);
1059 			bcopy(p->auth_srv_gids, *gids, *ngids * sizeof (gid_t));
1060 		}
1061 
1062 		access = p->auth_access;
1063 
1064 		if ((refresh > NFSAUTH_CACHE_REFRESH) &&
1065 		    p->auth_state == NFS_AUTH_FRESH) {
1066 			refreshq_auth_node_t *ran;
1067 			uint_t nacr;
1068 
1069 			p->auth_state = NFS_AUTH_STALE;
1070 			mutex_exit(&p->auth_lock);
1071 
1072 			nacr = atomic_inc_uint_nv(&nfsauth_cache_refresh);
1073 			DTRACE_PROBE3(nfsauth__debug__cache__stale,
1074 			    struct exportinfo *, exi,
1075 			    struct auth_cache *, p,
1076 			    uint_t, nacr);
1077 
1078 			ran = kmem_alloc(sizeof (refreshq_auth_node_t),
1079 			    KM_SLEEP);
1080 			ran->ran_auth = p;
1081 			ran->ran_netid = strdup(svc_getnetid(req->rq_xprt));
1082 
1083 			mutex_enter(&refreshq_lock);
1084 			/*
1085 			 * We should not add a work queue
1086 			 * item if the thread is not
1087 			 * accepting them.
1088 			 */
1089 			if (refreshq_thread_state == REFRESHQ_THREAD_RUNNING) {
1090 				refreshq_exi_node_t *ren;
1091 
1092 				/*
1093 				 * Is there an existing exi_list?
1094 				 */
1095 				for (ren = list_head(&refreshq_queue);
1096 				    ren != NULL;
1097 				    ren = list_next(&refreshq_queue, ren)) {
1098 					if (ren->ren_exi == exi) {
1099 						list_insert_tail(
1100 						    &ren->ren_authlist, ran);
1101 						break;
1102 					}
1103 				}
1104 
1105 				if (ren == NULL) {
1106 					ren = kmem_alloc(
1107 					    sizeof (refreshq_exi_node_t),
1108 					    KM_SLEEP);
1109 
1110 					exi_hold(exi);
1111 					ren->ren_exi = exi;
1112 
1113 					list_create(&ren->ren_authlist,
1114 					    sizeof (refreshq_auth_node_t),
1115 					    offsetof(refreshq_auth_node_t,
1116 					    ran_node));
1117 
1118 					list_insert_tail(&ren->ren_authlist,
1119 					    ran);
1120 					list_insert_tail(&refreshq_queue, ren);
1121 				}
1122 
1123 				cv_broadcast(&refreshq_cv);
1124 			} else {
1125 				strfree(ran->ran_netid);
1126 				kmem_free(ran, sizeof (refreshq_auth_node_t));
1127 			}
1128 
1129 			mutex_exit(&refreshq_lock);
1130 		} else {
1131 			mutex_exit(&p->auth_lock);
1132 		}
1133 
1134 		nach = atomic_inc_uint_nv(&nfsauth_cache_hit);
1135 		DTRACE_PROBE2(nfsauth__debug__cache__hit,
1136 		    uint_t, nach,
1137 		    time_t, refresh);
1138 
1139 		kmem_free(addr.buf, addr.maxlen);
1140 	}
1141 
1142 	return (access);
1143 
1144 retrieve:
1145 	crfree(ac.auth_clnt_cred);
1146 
1147 	/*
1148 	 * Retrieve the required data without caching.
1149 	 */
1150 
1151 	ASSERT(p == NULL);
1152 
1153 	atomic_inc_uint(&nfsauth_cache_miss);
1154 
1155 	if (nfsauth_retrieve(exi, svc_getnetid(req->rq_xprt), flavor, &addr,
1156 	    &access, cr, &tmpuid, &tmpgid, &tmpngids, &tmpgids)) {
1157 		if (uid != NULL)
1158 			*uid = tmpuid;
1159 		if (gid != NULL)
1160 			*gid = tmpgid;
1161 		if (ngids != NULL && gids != NULL) {
1162 			*ngids = tmpngids;
1163 			*gids = tmpgids;
1164 		} else {
1165 			kmem_free(tmpgids, tmpngids * sizeof (gid_t));
1166 		}
1167 	}
1168 
1169 	kmem_free(addr.buf, addr.maxlen);
1170 
1171 	return (access);
1172 }
1173 
1174 /*
1175  * Check if the requesting client has access to the filesystem with
1176  * a given nfs flavor number which is an explicitly shared flavor.
1177  */
1178 int
1179 nfsauth4_secinfo_access(struct exportinfo *exi, struct svc_req *req,
1180     int flavor, int perm, cred_t *cr)
1181 {
1182 	int access;
1183 
1184 	if (! (perm & M_4SEC_EXPORTED)) {
1185 		return (NFSAUTH_DENIED);
1186 	}
1187 
1188 	/*
1189 	 * Optimize if there are no lists
1190 	 */
1191 	if ((perm & (M_ROOT | M_NONE | M_MAP)) == 0) {
1192 		perm &= ~M_4SEC_EXPORTED;
1193 		if (perm == M_RO)
1194 			return (NFSAUTH_RO);
1195 		if (perm == M_RW)
1196 			return (NFSAUTH_RW);
1197 	}
1198 
1199 	access = nfsauth_cache_get(exi, req, flavor, cr, NULL, NULL, NULL,
1200 	    NULL);
1201 
1202 	return (access);
1203 }
1204 
1205 int
1206 nfsauth_access(struct exportinfo *exi, struct svc_req *req, cred_t *cr,
1207     uid_t *uid, gid_t *gid, uint_t *ngids, gid_t **gids)
1208 {
1209 	int access, mapaccess;
1210 	struct secinfo *sp;
1211 	int i, flavor, perm;
1212 	int authnone_entry = -1;
1213 
1214 	/*
1215 	 * By default root is mapped to anonymous user.
1216 	 * This might get overriden later in nfsauth_cache_get().
1217 	 */
1218 	if (crgetuid(cr) == 0) {
1219 		if (uid != NULL)
1220 			*uid = exi->exi_export.ex_anon;
1221 		if (gid != NULL)
1222 			*gid = exi->exi_export.ex_anon;
1223 	} else {
1224 		if (uid != NULL)
1225 			*uid = crgetuid(cr);
1226 		if (gid != NULL)
1227 			*gid = crgetgid(cr);
1228 	}
1229 
1230 	if (ngids != NULL)
1231 		*ngids = 0;
1232 	if (gids != NULL)
1233 		*gids = NULL;
1234 
1235 	/*
1236 	 *  Get the nfs flavor number from xprt.
1237 	 */
1238 	flavor = (int)(uintptr_t)req->rq_xprt->xp_cookie;
1239 
1240 	/*
1241 	 * First check the access restrictions on the filesystem.  If
1242 	 * there are no lists associated with this flavor then there's no
1243 	 * need to make an expensive call to the nfsauth service or to
1244 	 * cache anything.
1245 	 */
1246 
1247 	sp = exi->exi_export.ex_secinfo;
1248 	for (i = 0; i < exi->exi_export.ex_seccnt; i++) {
1249 		if (flavor != sp[i].s_secinfo.sc_nfsnum) {
1250 			if (sp[i].s_secinfo.sc_nfsnum == AUTH_NONE)
1251 				authnone_entry = i;
1252 			continue;
1253 		}
1254 		break;
1255 	}
1256 
1257 	mapaccess = 0;
1258 
1259 	if (i >= exi->exi_export.ex_seccnt) {
1260 		/*
1261 		 * Flavor not found, but use AUTH_NONE if it exists
1262 		 */
1263 		if (authnone_entry == -1)
1264 			return (NFSAUTH_DENIED);
1265 		flavor = AUTH_NONE;
1266 		mapaccess = NFSAUTH_MAPNONE;
1267 		i = authnone_entry;
1268 	}
1269 
1270 	/*
1271 	 * If the flavor is in the ex_secinfo list, but not an explicitly
1272 	 * shared flavor by the user, it is a result of the nfsv4 server
1273 	 * namespace setup. We will grant an RO permission similar for
1274 	 * a pseudo node except that this node is a shared one.
1275 	 *
1276 	 * e.g. flavor in (flavor) indicates that it is not explictly
1277 	 *	shared by the user:
1278 	 *
1279 	 *		/	(sys, krb5)
1280 	 *		|
1281 	 *		export  #share -o sec=sys (krb5)
1282 	 *		|
1283 	 *		secure  #share -o sec=krb5
1284 	 *
1285 	 *	In this case, when a krb5 request coming in to access
1286 	 *	/export, RO permission is granted.
1287 	 */
1288 	if (!(sp[i].s_flags & M_4SEC_EXPORTED))
1289 		return (mapaccess | NFSAUTH_RO);
1290 
1291 	/*
1292 	 * Optimize if there are no lists.
1293 	 * We cannot optimize for AUTH_SYS with NGRPS (16) supplemental groups.
1294 	 */
1295 	perm = sp[i].s_flags;
1296 	if ((perm & (M_ROOT | M_NONE | M_MAP)) == 0 && (ngroups_max <= NGRPS ||
1297 	    flavor != AUTH_SYS || crgetngroups(cr) < NGRPS)) {
1298 		perm &= ~M_4SEC_EXPORTED;
1299 		if (perm == M_RO)
1300 			return (mapaccess | NFSAUTH_RO);
1301 		if (perm == M_RW)
1302 			return (mapaccess | NFSAUTH_RW);
1303 	}
1304 
1305 	access = nfsauth_cache_get(exi, req, flavor, cr, uid, gid, ngids, gids);
1306 
1307 	/*
1308 	 * For both NFSAUTH_DENIED and NFSAUTH_WRONGSEC we do not care about
1309 	 * the supplemental groups.
1310 	 */
1311 	if (access & NFSAUTH_DENIED || access & NFSAUTH_WRONGSEC) {
1312 		if (ngids != NULL && gids != NULL) {
1313 			kmem_free(*gids, *ngids * sizeof (gid_t));
1314 			*ngids = 0;
1315 			*gids = NULL;
1316 		}
1317 	}
1318 
1319 	/*
1320 	 * Client's security flavor doesn't match with "ro" or
1321 	 * "rw" list. Try again using AUTH_NONE if present.
1322 	 */
1323 	if ((access & NFSAUTH_WRONGSEC) && (flavor != AUTH_NONE)) {
1324 		/*
1325 		 * Have we already encountered AUTH_NONE ?
1326 		 */
1327 		if (authnone_entry != -1) {
1328 			mapaccess = NFSAUTH_MAPNONE;
1329 			access = nfsauth_cache_get(exi, req, AUTH_NONE, cr,
1330 			    NULL, NULL, NULL, NULL);
1331 		} else {
1332 			/*
1333 			 * Check for AUTH_NONE presence.
1334 			 */
1335 			for (; i < exi->exi_export.ex_seccnt; i++) {
1336 				if (sp[i].s_secinfo.sc_nfsnum == AUTH_NONE) {
1337 					mapaccess = NFSAUTH_MAPNONE;
1338 					access = nfsauth_cache_get(exi, req,
1339 					    AUTH_NONE, cr, NULL, NULL, NULL,
1340 					    NULL);
1341 					break;
1342 				}
1343 			}
1344 		}
1345 	}
1346 
1347 	if (access & NFSAUTH_DENIED)
1348 		access = NFSAUTH_DENIED;
1349 
1350 	return (access | mapaccess);
1351 }
1352 
1353 static void
1354 nfsauth_free_clnt_node(struct auth_cache_clnt *p)
1355 {
1356 	void *cookie = NULL;
1357 	struct auth_cache *node;
1358 
1359 	while ((node = avl_destroy_nodes(&p->authc_tree, &cookie)) != NULL)
1360 		nfsauth_free_node(node);
1361 	avl_destroy(&p->authc_tree);
1362 
1363 	kmem_free(p->authc_addr.buf, p->authc_addr.maxlen);
1364 	rw_destroy(&p->authc_lock);
1365 
1366 	kmem_free(p, sizeof (*p));
1367 }
1368 
1369 static void
1370 nfsauth_free_node(struct auth_cache *p)
1371 {
1372 	crfree(p->auth_clnt_cred);
1373 	kmem_free(p->auth_srv_gids, p->auth_srv_ngids * sizeof (gid_t));
1374 	mutex_destroy(&p->auth_lock);
1375 	cv_destroy(&p->auth_cv);
1376 	kmem_cache_free(exi_cache_handle, p);
1377 }
1378 
1379 /*
1380  * Free the nfsauth cache for a given export
1381  */
1382 void
1383 nfsauth_cache_free(struct exportinfo *exi)
1384 {
1385 	int i;
1386 
1387 	/*
1388 	 * The only way we got here was with an exi_rele, which means that no
1389 	 * auth cache entry is being refreshed.
1390 	 */
1391 
1392 	for (i = 0; i < AUTH_TABLESIZE; i++) {
1393 		avl_tree_t *tree = exi->exi_cache[i];
1394 		void *cookie = NULL;
1395 		struct auth_cache_clnt *node;
1396 
1397 		while ((node = avl_destroy_nodes(tree, &cookie)) != NULL)
1398 			nfsauth_free_clnt_node(node);
1399 	}
1400 }
1401 
1402 /*
1403  * Called by the kernel memory allocator when
1404  * memory is low. Free unused cache entries.
1405  * If that's not enough, the VM system will
1406  * call again for some more.
1407  */
1408 /*ARGSUSED*/
1409 void
1410 exi_cache_reclaim(void *cdrarg)
1411 {
1412 	int i;
1413 	struct exportinfo *exi;
1414 
1415 	rw_enter(&exported_lock, RW_READER);
1416 
1417 	for (i = 0; i < EXPTABLESIZE; i++) {
1418 		for (exi = exptable[i]; exi; exi = exi->fid_hash.next) {
1419 			exi_cache_trim(exi);
1420 		}
1421 	}
1422 
1423 	rw_exit(&exported_lock);
1424 
1425 	atomic_inc_uint(&nfsauth_cache_reclaim);
1426 }
1427 
1428 void
1429 exi_cache_trim(struct exportinfo *exi)
1430 {
1431 	struct auth_cache_clnt *c;
1432 	struct auth_cache_clnt *nextc;
1433 	struct auth_cache *p;
1434 	struct auth_cache *next;
1435 	int i;
1436 	time_t stale_time;
1437 	avl_tree_t *tree;
1438 
1439 	for (i = 0; i < AUTH_TABLESIZE; i++) {
1440 		tree = exi->exi_cache[i];
1441 		stale_time = gethrestime_sec() - NFSAUTH_CACHE_TRIM;
1442 		rw_enter(&exi->exi_cache_lock, RW_READER);
1443 
1444 		/*
1445 		 * Free entries that have not been
1446 		 * used for NFSAUTH_CACHE_TRIM seconds.
1447 		 */
1448 		for (c = avl_first(tree); c != NULL; c = AVL_NEXT(tree, c)) {
1449 			/*
1450 			 * We are being called by the kmem subsystem to reclaim
1451 			 * memory so don't block if we can't get the lock.
1452 			 */
1453 			if (rw_tryenter(&c->authc_lock, RW_WRITER) == 0) {
1454 				exi_cache_auth_reclaim_failed++;
1455 				rw_exit(&exi->exi_cache_lock);
1456 				return;
1457 			}
1458 
1459 			for (p = avl_first(&c->authc_tree); p != NULL;
1460 			    p = next) {
1461 				next = AVL_NEXT(&c->authc_tree, p);
1462 
1463 				ASSERT(p->auth_state != NFS_AUTH_INVALID);
1464 
1465 				mutex_enter(&p->auth_lock);
1466 
1467 				/*
1468 				 * We won't trim recently used and/or WAITING
1469 				 * entries.
1470 				 */
1471 				if (p->auth_time > stale_time ||
1472 				    p->auth_state == NFS_AUTH_WAITING) {
1473 					mutex_exit(&p->auth_lock);
1474 					continue;
1475 				}
1476 
1477 				DTRACE_PROBE1(nfsauth__debug__trim__state,
1478 				    auth_state_t, p->auth_state);
1479 
1480 				/*
1481 				 * STALE and REFRESHING entries needs to be
1482 				 * marked INVALID only because they are
1483 				 * referenced by some other structures or
1484 				 * threads.  They will be freed later.
1485 				 */
1486 				if (p->auth_state == NFS_AUTH_STALE ||
1487 				    p->auth_state == NFS_AUTH_REFRESHING) {
1488 					p->auth_state = NFS_AUTH_INVALID;
1489 					mutex_exit(&p->auth_lock);
1490 
1491 					avl_remove(&c->authc_tree, p);
1492 				} else {
1493 					mutex_exit(&p->auth_lock);
1494 
1495 					avl_remove(&c->authc_tree, p);
1496 					nfsauth_free_node(p);
1497 				}
1498 			}
1499 			rw_exit(&c->authc_lock);
1500 		}
1501 
1502 		if (rw_tryupgrade(&exi->exi_cache_lock) == 0) {
1503 			rw_exit(&exi->exi_cache_lock);
1504 			exi_cache_clnt_reclaim_failed++;
1505 			continue;
1506 		}
1507 
1508 		for (c = avl_first(tree); c != NULL; c = nextc) {
1509 			nextc = AVL_NEXT(tree, c);
1510 
1511 			if (avl_is_empty(&c->authc_tree) == B_FALSE)
1512 				continue;
1513 
1514 			avl_remove(tree, c);
1515 
1516 			nfsauth_free_clnt_node(c);
1517 		}
1518 
1519 		rw_exit(&exi->exi_cache_lock);
1520 	}
1521 }
1522