xref: /openbmc/linux/net/sunrpc/svcauth_unix.c (revision c21b37f6)
1 #include <linux/types.h>
2 #include <linux/sched.h>
3 #include <linux/module.h>
4 #include <linux/sunrpc/types.h>
5 #include <linux/sunrpc/xdr.h>
6 #include <linux/sunrpc/svcsock.h>
7 #include <linux/sunrpc/svcauth.h>
8 #include <linux/sunrpc/gss_api.h>
9 #include <linux/err.h>
10 #include <linux/seq_file.h>
11 #include <linux/hash.h>
12 #include <linux/string.h>
13 #include <net/sock.h>
14 
15 #define RPCDBG_FACILITY	RPCDBG_AUTH
16 
17 
18 /*
19  * AUTHUNIX and AUTHNULL credentials are both handled here.
20  * AUTHNULL is treated just like AUTHUNIX except that the uid/gid
21  * are always nobody (-2).  i.e. we do the same IP address checks for
22  * AUTHNULL as for AUTHUNIX, and that is done here.
23  */
24 
25 
26 struct unix_domain {
27 	struct auth_domain	h;
28 	int	addr_changes;
29 	/* other stuff later */
30 };
31 
32 extern struct auth_ops svcauth_unix;
33 
34 struct auth_domain *unix_domain_find(char *name)
35 {
36 	struct auth_domain *rv;
37 	struct unix_domain *new = NULL;
38 
39 	rv = auth_domain_lookup(name, NULL);
40 	while(1) {
41 		if (rv) {
42 			if (new && rv != &new->h)
43 				auth_domain_put(&new->h);
44 
45 			if (rv->flavour != &svcauth_unix) {
46 				auth_domain_put(rv);
47 				return NULL;
48 			}
49 			return rv;
50 		}
51 
52 		new = kmalloc(sizeof(*new), GFP_KERNEL);
53 		if (new == NULL)
54 			return NULL;
55 		kref_init(&new->h.ref);
56 		new->h.name = kstrdup(name, GFP_KERNEL);
57 		if (new->h.name == NULL) {
58 			kfree(new);
59 			return NULL;
60 		}
61 		new->h.flavour = &svcauth_unix;
62 		new->addr_changes = 0;
63 		rv = auth_domain_lookup(name, &new->h);
64 	}
65 }
66 
67 static void svcauth_unix_domain_release(struct auth_domain *dom)
68 {
69 	struct unix_domain *ud = container_of(dom, struct unix_domain, h);
70 
71 	kfree(dom->name);
72 	kfree(ud);
73 }
74 
75 
76 /**************************************************
77  * cache for IP address to unix_domain
78  * as needed by AUTH_UNIX
79  */
80 #define	IP_HASHBITS	8
81 #define	IP_HASHMAX	(1<<IP_HASHBITS)
82 #define	IP_HASHMASK	(IP_HASHMAX-1)
83 
84 struct ip_map {
85 	struct cache_head	h;
86 	char			m_class[8]; /* e.g. "nfsd" */
87 	struct in_addr		m_addr;
88 	struct unix_domain	*m_client;
89 	int			m_add_change;
90 };
91 static struct cache_head	*ip_table[IP_HASHMAX];
92 
93 static void ip_map_put(struct kref *kref)
94 {
95 	struct cache_head *item = container_of(kref, struct cache_head, ref);
96 	struct ip_map *im = container_of(item, struct ip_map,h);
97 
98 	if (test_bit(CACHE_VALID, &item->flags) &&
99 	    !test_bit(CACHE_NEGATIVE, &item->flags))
100 		auth_domain_put(&im->m_client->h);
101 	kfree(im);
102 }
103 
104 #if IP_HASHBITS == 8
105 /* hash_long on a 64 bit machine is currently REALLY BAD for
106  * IP addresses in reverse-endian (i.e. on a little-endian machine).
107  * So use a trivial but reliable hash instead
108  */
109 static inline int hash_ip(__be32 ip)
110 {
111 	int hash = (__force u32)ip ^ ((__force u32)ip>>16);
112 	return (hash ^ (hash>>8)) & 0xff;
113 }
114 #endif
115 static int ip_map_match(struct cache_head *corig, struct cache_head *cnew)
116 {
117 	struct ip_map *orig = container_of(corig, struct ip_map, h);
118 	struct ip_map *new = container_of(cnew, struct ip_map, h);
119 	return strcmp(orig->m_class, new->m_class) == 0
120 		&& orig->m_addr.s_addr == new->m_addr.s_addr;
121 }
122 static void ip_map_init(struct cache_head *cnew, struct cache_head *citem)
123 {
124 	struct ip_map *new = container_of(cnew, struct ip_map, h);
125 	struct ip_map *item = container_of(citem, struct ip_map, h);
126 
127 	strcpy(new->m_class, item->m_class);
128 	new->m_addr.s_addr = item->m_addr.s_addr;
129 }
130 static void update(struct cache_head *cnew, struct cache_head *citem)
131 {
132 	struct ip_map *new = container_of(cnew, struct ip_map, h);
133 	struct ip_map *item = container_of(citem, struct ip_map, h);
134 
135 	kref_get(&item->m_client->h.ref);
136 	new->m_client = item->m_client;
137 	new->m_add_change = item->m_add_change;
138 }
139 static struct cache_head *ip_map_alloc(void)
140 {
141 	struct ip_map *i = kmalloc(sizeof(*i), GFP_KERNEL);
142 	if (i)
143 		return &i->h;
144 	else
145 		return NULL;
146 }
147 
148 static void ip_map_request(struct cache_detail *cd,
149 				  struct cache_head *h,
150 				  char **bpp, int *blen)
151 {
152 	char text_addr[20];
153 	struct ip_map *im = container_of(h, struct ip_map, h);
154 	__be32 addr = im->m_addr.s_addr;
155 
156 	snprintf(text_addr, 20, "%u.%u.%u.%u",
157 		 ntohl(addr) >> 24 & 0xff,
158 		 ntohl(addr) >> 16 & 0xff,
159 		 ntohl(addr) >>  8 & 0xff,
160 		 ntohl(addr) >>  0 & 0xff);
161 
162 	qword_add(bpp, blen, im->m_class);
163 	qword_add(bpp, blen, text_addr);
164 	(*bpp)[-1] = '\n';
165 }
166 
167 static struct ip_map *ip_map_lookup(char *class, struct in_addr addr);
168 static int ip_map_update(struct ip_map *ipm, struct unix_domain *udom, time_t expiry);
169 
170 static int ip_map_parse(struct cache_detail *cd,
171 			  char *mesg, int mlen)
172 {
173 	/* class ipaddress [domainname] */
174 	/* should be safe just to use the start of the input buffer
175 	 * for scratch: */
176 	char *buf = mesg;
177 	int len;
178 	int b1,b2,b3,b4;
179 	char c;
180 	char class[8];
181 	struct in_addr addr;
182 	int err;
183 
184 	struct ip_map *ipmp;
185 	struct auth_domain *dom;
186 	time_t expiry;
187 
188 	if (mesg[mlen-1] != '\n')
189 		return -EINVAL;
190 	mesg[mlen-1] = 0;
191 
192 	/* class */
193 	len = qword_get(&mesg, class, sizeof(class));
194 	if (len <= 0) return -EINVAL;
195 
196 	/* ip address */
197 	len = qword_get(&mesg, buf, mlen);
198 	if (len <= 0) return -EINVAL;
199 
200 	if (sscanf(buf, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
201 		return -EINVAL;
202 
203 	expiry = get_expiry(&mesg);
204 	if (expiry ==0)
205 		return -EINVAL;
206 
207 	/* domainname, or empty for NEGATIVE */
208 	len = qword_get(&mesg, buf, mlen);
209 	if (len < 0) return -EINVAL;
210 
211 	if (len) {
212 		dom = unix_domain_find(buf);
213 		if (dom == NULL)
214 			return -ENOENT;
215 	} else
216 		dom = NULL;
217 
218 	addr.s_addr =
219 		htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);
220 
221 	ipmp = ip_map_lookup(class,addr);
222 	if (ipmp) {
223 		err = ip_map_update(ipmp,
224 			     container_of(dom, struct unix_domain, h),
225 			     expiry);
226 	} else
227 		err = -ENOMEM;
228 
229 	if (dom)
230 		auth_domain_put(dom);
231 
232 	cache_flush();
233 	return err;
234 }
235 
236 static int ip_map_show(struct seq_file *m,
237 		       struct cache_detail *cd,
238 		       struct cache_head *h)
239 {
240 	struct ip_map *im;
241 	struct in_addr addr;
242 	char *dom = "-no-domain-";
243 
244 	if (h == NULL) {
245 		seq_puts(m, "#class IP domain\n");
246 		return 0;
247 	}
248 	im = container_of(h, struct ip_map, h);
249 	/* class addr domain */
250 	addr = im->m_addr;
251 
252 	if (test_bit(CACHE_VALID, &h->flags) &&
253 	    !test_bit(CACHE_NEGATIVE, &h->flags))
254 		dom = im->m_client->h.name;
255 
256 	seq_printf(m, "%s %d.%d.%d.%d %s\n",
257 		   im->m_class,
258 		   ntohl(addr.s_addr) >> 24 & 0xff,
259 		   ntohl(addr.s_addr) >> 16 & 0xff,
260 		   ntohl(addr.s_addr) >>  8 & 0xff,
261 		   ntohl(addr.s_addr) >>  0 & 0xff,
262 		   dom
263 		   );
264 	return 0;
265 }
266 
267 
268 struct cache_detail ip_map_cache = {
269 	.owner		= THIS_MODULE,
270 	.hash_size	= IP_HASHMAX,
271 	.hash_table	= ip_table,
272 	.name		= "auth.unix.ip",
273 	.cache_put	= ip_map_put,
274 	.cache_request	= ip_map_request,
275 	.cache_parse	= ip_map_parse,
276 	.cache_show	= ip_map_show,
277 	.match		= ip_map_match,
278 	.init		= ip_map_init,
279 	.update		= update,
280 	.alloc		= ip_map_alloc,
281 };
282 
283 static struct ip_map *ip_map_lookup(char *class, struct in_addr addr)
284 {
285 	struct ip_map ip;
286 	struct cache_head *ch;
287 
288 	strcpy(ip.m_class, class);
289 	ip.m_addr = addr;
290 	ch = sunrpc_cache_lookup(&ip_map_cache, &ip.h,
291 				 hash_str(class, IP_HASHBITS) ^
292 				 hash_ip(addr.s_addr));
293 
294 	if (ch)
295 		return container_of(ch, struct ip_map, h);
296 	else
297 		return NULL;
298 }
299 
300 static int ip_map_update(struct ip_map *ipm, struct unix_domain *udom, time_t expiry)
301 {
302 	struct ip_map ip;
303 	struct cache_head *ch;
304 
305 	ip.m_client = udom;
306 	ip.h.flags = 0;
307 	if (!udom)
308 		set_bit(CACHE_NEGATIVE, &ip.h.flags);
309 	else {
310 		ip.m_add_change = udom->addr_changes;
311 		/* if this is from the legacy set_client system call,
312 		 * we need m_add_change to be one higher
313 		 */
314 		if (expiry == NEVER)
315 			ip.m_add_change++;
316 	}
317 	ip.h.expiry_time = expiry;
318 	ch = sunrpc_cache_update(&ip_map_cache,
319 				 &ip.h, &ipm->h,
320 				 hash_str(ipm->m_class, IP_HASHBITS) ^
321 				 hash_ip(ipm->m_addr.s_addr));
322 	if (!ch)
323 		return -ENOMEM;
324 	cache_put(ch, &ip_map_cache);
325 	return 0;
326 }
327 
328 int auth_unix_add_addr(struct in_addr addr, struct auth_domain *dom)
329 {
330 	struct unix_domain *udom;
331 	struct ip_map *ipmp;
332 
333 	if (dom->flavour != &svcauth_unix)
334 		return -EINVAL;
335 	udom = container_of(dom, struct unix_domain, h);
336 	ipmp = ip_map_lookup("nfsd", addr);
337 
338 	if (ipmp)
339 		return ip_map_update(ipmp, udom, NEVER);
340 	else
341 		return -ENOMEM;
342 }
343 
344 int auth_unix_forget_old(struct auth_domain *dom)
345 {
346 	struct unix_domain *udom;
347 
348 	if (dom->flavour != &svcauth_unix)
349 		return -EINVAL;
350 	udom = container_of(dom, struct unix_domain, h);
351 	udom->addr_changes++;
352 	return 0;
353 }
354 
355 struct auth_domain *auth_unix_lookup(struct in_addr addr)
356 {
357 	struct ip_map *ipm;
358 	struct auth_domain *rv;
359 
360 	ipm = ip_map_lookup("nfsd", addr);
361 
362 	if (!ipm)
363 		return NULL;
364 	if (cache_check(&ip_map_cache, &ipm->h, NULL))
365 		return NULL;
366 
367 	if ((ipm->m_client->addr_changes - ipm->m_add_change) >0) {
368 		if (test_and_set_bit(CACHE_NEGATIVE, &ipm->h.flags) == 0)
369 			auth_domain_put(&ipm->m_client->h);
370 		rv = NULL;
371 	} else {
372 		rv = &ipm->m_client->h;
373 		kref_get(&rv->ref);
374 	}
375 	cache_put(&ipm->h, &ip_map_cache);
376 	return rv;
377 }
378 
379 void svcauth_unix_purge(void)
380 {
381 	cache_purge(&ip_map_cache);
382 }
383 
384 static inline struct ip_map *
385 ip_map_cached_get(struct svc_rqst *rqstp)
386 {
387 	struct ip_map *ipm;
388 	struct svc_sock *svsk = rqstp->rq_sock;
389 	spin_lock(&svsk->sk_lock);
390 	ipm = svsk->sk_info_authunix;
391 	if (ipm != NULL) {
392 		if (!cache_valid(&ipm->h)) {
393 			/*
394 			 * The entry has been invalidated since it was
395 			 * remembered, e.g. by a second mount from the
396 			 * same IP address.
397 			 */
398 			svsk->sk_info_authunix = NULL;
399 			spin_unlock(&svsk->sk_lock);
400 			cache_put(&ipm->h, &ip_map_cache);
401 			return NULL;
402 		}
403 		cache_get(&ipm->h);
404 	}
405 	spin_unlock(&svsk->sk_lock);
406 	return ipm;
407 }
408 
409 static inline void
410 ip_map_cached_put(struct svc_rqst *rqstp, struct ip_map *ipm)
411 {
412 	struct svc_sock *svsk = rqstp->rq_sock;
413 
414 	spin_lock(&svsk->sk_lock);
415 	if (svsk->sk_sock->type == SOCK_STREAM &&
416 	    svsk->sk_info_authunix == NULL) {
417 		/* newly cached, keep the reference */
418 		svsk->sk_info_authunix = ipm;
419 		ipm = NULL;
420 	}
421 	spin_unlock(&svsk->sk_lock);
422 	if (ipm)
423 		cache_put(&ipm->h, &ip_map_cache);
424 }
425 
426 void
427 svcauth_unix_info_release(void *info)
428 {
429 	struct ip_map *ipm = info;
430 	cache_put(&ipm->h, &ip_map_cache);
431 }
432 
433 /****************************************************************************
434  * auth.unix.gid cache
435  * simple cache to map a UID to a list of GIDs
436  * because AUTH_UNIX aka AUTH_SYS has a max of 16
437  */
438 #define	GID_HASHBITS	8
439 #define	GID_HASHMAX	(1<<GID_HASHBITS)
440 #define	GID_HASHMASK	(GID_HASHMAX - 1)
441 
442 struct unix_gid {
443 	struct cache_head	h;
444 	uid_t			uid;
445 	struct group_info	*gi;
446 };
447 static struct cache_head	*gid_table[GID_HASHMAX];
448 
449 static void unix_gid_put(struct kref *kref)
450 {
451 	struct cache_head *item = container_of(kref, struct cache_head, ref);
452 	struct unix_gid *ug = container_of(item, struct unix_gid, h);
453 	if (test_bit(CACHE_VALID, &item->flags) &&
454 	    !test_bit(CACHE_NEGATIVE, &item->flags))
455 		put_group_info(ug->gi);
456 	kfree(ug);
457 }
458 
459 static int unix_gid_match(struct cache_head *corig, struct cache_head *cnew)
460 {
461 	struct unix_gid *orig = container_of(corig, struct unix_gid, h);
462 	struct unix_gid *new = container_of(cnew, struct unix_gid, h);
463 	return orig->uid == new->uid;
464 }
465 static void unix_gid_init(struct cache_head *cnew, struct cache_head *citem)
466 {
467 	struct unix_gid *new = container_of(cnew, struct unix_gid, h);
468 	struct unix_gid *item = container_of(citem, struct unix_gid, h);
469 	new->uid = item->uid;
470 }
471 static void unix_gid_update(struct cache_head *cnew, struct cache_head *citem)
472 {
473 	struct unix_gid *new = container_of(cnew, struct unix_gid, h);
474 	struct unix_gid *item = container_of(citem, struct unix_gid, h);
475 
476 	get_group_info(item->gi);
477 	new->gi = item->gi;
478 }
479 static struct cache_head *unix_gid_alloc(void)
480 {
481 	struct unix_gid *g = kmalloc(sizeof(*g), GFP_KERNEL);
482 	if (g)
483 		return &g->h;
484 	else
485 		return NULL;
486 }
487 
488 static void unix_gid_request(struct cache_detail *cd,
489 			     struct cache_head *h,
490 			     char **bpp, int *blen)
491 {
492 	char tuid[20];
493 	struct unix_gid *ug = container_of(h, struct unix_gid, h);
494 
495 	snprintf(tuid, 20, "%u", ug->uid);
496 	qword_add(bpp, blen, tuid);
497 	(*bpp)[-1] = '\n';
498 }
499 
500 static struct unix_gid *unix_gid_lookup(uid_t uid);
501 extern struct cache_detail unix_gid_cache;
502 
503 static int unix_gid_parse(struct cache_detail *cd,
504 			char *mesg, int mlen)
505 {
506 	/* uid expiry Ngid gid0 gid1 ... gidN-1 */
507 	int uid;
508 	int gids;
509 	int rv;
510 	int i;
511 	int err;
512 	time_t expiry;
513 	struct unix_gid ug, *ugp;
514 
515 	if (mlen <= 0 || mesg[mlen-1] != '\n')
516 		return -EINVAL;
517 	mesg[mlen-1] = 0;
518 
519 	rv = get_int(&mesg, &uid);
520 	if (rv)
521 		return -EINVAL;
522 	ug.uid = uid;
523 
524 	expiry = get_expiry(&mesg);
525 	if (expiry == 0)
526 		return -EINVAL;
527 
528 	rv = get_int(&mesg, &gids);
529 	if (rv || gids < 0 || gids > 8192)
530 		return -EINVAL;
531 
532 	ug.gi = groups_alloc(gids);
533 	if (!ug.gi)
534 		return -ENOMEM;
535 
536 	for (i = 0 ; i < gids ; i++) {
537 		int gid;
538 		rv = get_int(&mesg, &gid);
539 		err = -EINVAL;
540 		if (rv)
541 			goto out;
542 		GROUP_AT(ug.gi, i) = gid;
543 	}
544 
545 	ugp = unix_gid_lookup(uid);
546 	if (ugp) {
547 		struct cache_head *ch;
548 		ug.h.flags = 0;
549 		ug.h.expiry_time = expiry;
550 		ch = sunrpc_cache_update(&unix_gid_cache,
551 					 &ug.h, &ugp->h,
552 					 hash_long(uid, GID_HASHBITS));
553 		if (!ch)
554 			err = -ENOMEM;
555 		else {
556 			err = 0;
557 			cache_put(ch, &unix_gid_cache);
558 		}
559 	} else
560 		err = -ENOMEM;
561  out:
562 	if (ug.gi)
563 		put_group_info(ug.gi);
564 	return err;
565 }
566 
567 static int unix_gid_show(struct seq_file *m,
568 			 struct cache_detail *cd,
569 			 struct cache_head *h)
570 {
571 	struct unix_gid *ug;
572 	int i;
573 	int glen;
574 
575 	if (h == NULL) {
576 		seq_puts(m, "#uid cnt: gids...\n");
577 		return 0;
578 	}
579 	ug = container_of(h, struct unix_gid, h);
580 	if (test_bit(CACHE_VALID, &h->flags) &&
581 	    !test_bit(CACHE_NEGATIVE, &h->flags))
582 		glen = ug->gi->ngroups;
583 	else
584 		glen = 0;
585 
586 	seq_printf(m, "%d %d:", ug->uid, glen);
587 	for (i = 0; i < glen; i++)
588 		seq_printf(m, " %d", GROUP_AT(ug->gi, i));
589 	seq_printf(m, "\n");
590 	return 0;
591 }
592 
593 struct cache_detail unix_gid_cache = {
594 	.owner		= THIS_MODULE,
595 	.hash_size	= GID_HASHMAX,
596 	.hash_table	= gid_table,
597 	.name		= "auth.unix.gid",
598 	.cache_put	= unix_gid_put,
599 	.cache_request	= unix_gid_request,
600 	.cache_parse	= unix_gid_parse,
601 	.cache_show	= unix_gid_show,
602 	.match		= unix_gid_match,
603 	.init		= unix_gid_init,
604 	.update		= unix_gid_update,
605 	.alloc		= unix_gid_alloc,
606 };
607 
608 static struct unix_gid *unix_gid_lookup(uid_t uid)
609 {
610 	struct unix_gid ug;
611 	struct cache_head *ch;
612 
613 	ug.uid = uid;
614 	ch = sunrpc_cache_lookup(&unix_gid_cache, &ug.h,
615 				 hash_long(uid, GID_HASHBITS));
616 	if (ch)
617 		return container_of(ch, struct unix_gid, h);
618 	else
619 		return NULL;
620 }
621 
622 static int unix_gid_find(uid_t uid, struct group_info **gip,
623 			 struct svc_rqst *rqstp)
624 {
625 	struct unix_gid *ug = unix_gid_lookup(uid);
626 	if (!ug)
627 		return -EAGAIN;
628 	switch (cache_check(&unix_gid_cache, &ug->h, &rqstp->rq_chandle)) {
629 	case -ENOENT:
630 		*gip = NULL;
631 		return 0;
632 	case 0:
633 		*gip = ug->gi;
634 		get_group_info(*gip);
635 		return 0;
636 	default:
637 		return -EAGAIN;
638 	}
639 }
640 
641 int
642 svcauth_unix_set_client(struct svc_rqst *rqstp)
643 {
644 	struct sockaddr_in *sin = svc_addr_in(rqstp);
645 	struct ip_map *ipm;
646 
647 	rqstp->rq_client = NULL;
648 	if (rqstp->rq_proc == 0)
649 		return SVC_OK;
650 
651 	ipm = ip_map_cached_get(rqstp);
652 	if (ipm == NULL)
653 		ipm = ip_map_lookup(rqstp->rq_server->sv_program->pg_class,
654 				    sin->sin_addr);
655 
656 	if (ipm == NULL)
657 		return SVC_DENIED;
658 
659 	switch (cache_check(&ip_map_cache, &ipm->h, &rqstp->rq_chandle)) {
660 		default:
661 			BUG();
662 		case -EAGAIN:
663 		case -ETIMEDOUT:
664 			return SVC_DROP;
665 		case -ENOENT:
666 			return SVC_DENIED;
667 		case 0:
668 			rqstp->rq_client = &ipm->m_client->h;
669 			kref_get(&rqstp->rq_client->ref);
670 			ip_map_cached_put(rqstp, ipm);
671 			break;
672 	}
673 	return SVC_OK;
674 }
675 
676 EXPORT_SYMBOL(svcauth_unix_set_client);
677 
678 static int
679 svcauth_null_accept(struct svc_rqst *rqstp, __be32 *authp)
680 {
681 	struct kvec	*argv = &rqstp->rq_arg.head[0];
682 	struct kvec	*resv = &rqstp->rq_res.head[0];
683 	struct svc_cred	*cred = &rqstp->rq_cred;
684 
685 	cred->cr_group_info = NULL;
686 	rqstp->rq_client = NULL;
687 
688 	if (argv->iov_len < 3*4)
689 		return SVC_GARBAGE;
690 
691 	if (svc_getu32(argv) != 0) {
692 		dprintk("svc: bad null cred\n");
693 		*authp = rpc_autherr_badcred;
694 		return SVC_DENIED;
695 	}
696 	if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {
697 		dprintk("svc: bad null verf\n");
698 		*authp = rpc_autherr_badverf;
699 		return SVC_DENIED;
700 	}
701 
702 	/* Signal that mapping to nobody uid/gid is required */
703 	cred->cr_uid = (uid_t) -1;
704 	cred->cr_gid = (gid_t) -1;
705 	cred->cr_group_info = groups_alloc(0);
706 	if (cred->cr_group_info == NULL)
707 		return SVC_DROP; /* kmalloc failure - client must retry */
708 
709 	/* Put NULL verifier */
710 	svc_putnl(resv, RPC_AUTH_NULL);
711 	svc_putnl(resv, 0);
712 
713 	rqstp->rq_flavor = RPC_AUTH_NULL;
714 	return SVC_OK;
715 }
716 
717 static int
718 svcauth_null_release(struct svc_rqst *rqstp)
719 {
720 	if (rqstp->rq_client)
721 		auth_domain_put(rqstp->rq_client);
722 	rqstp->rq_client = NULL;
723 	if (rqstp->rq_cred.cr_group_info)
724 		put_group_info(rqstp->rq_cred.cr_group_info);
725 	rqstp->rq_cred.cr_group_info = NULL;
726 
727 	return 0; /* don't drop */
728 }
729 
730 
731 struct auth_ops svcauth_null = {
732 	.name		= "null",
733 	.owner		= THIS_MODULE,
734 	.flavour	= RPC_AUTH_NULL,
735 	.accept 	= svcauth_null_accept,
736 	.release	= svcauth_null_release,
737 	.set_client	= svcauth_unix_set_client,
738 };
739 
740 
741 static int
742 svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
743 {
744 	struct kvec	*argv = &rqstp->rq_arg.head[0];
745 	struct kvec	*resv = &rqstp->rq_res.head[0];
746 	struct svc_cred	*cred = &rqstp->rq_cred;
747 	u32		slen, i;
748 	int		len   = argv->iov_len;
749 
750 	cred->cr_group_info = NULL;
751 	rqstp->rq_client = NULL;
752 
753 	if ((len -= 3*4) < 0)
754 		return SVC_GARBAGE;
755 
756 	svc_getu32(argv);			/* length */
757 	svc_getu32(argv);			/* time stamp */
758 	slen = XDR_QUADLEN(svc_getnl(argv));	/* machname length */
759 	if (slen > 64 || (len -= (slen + 3)*4) < 0)
760 		goto badcred;
761 	argv->iov_base = (void*)((__be32*)argv->iov_base + slen);	/* skip machname */
762 	argv->iov_len -= slen*4;
763 
764 	cred->cr_uid = svc_getnl(argv);		/* uid */
765 	cred->cr_gid = svc_getnl(argv);		/* gid */
766 	slen = svc_getnl(argv);			/* gids length */
767 	if (slen > 16 || (len -= (slen + 2)*4) < 0)
768 		goto badcred;
769 	if (unix_gid_find(cred->cr_uid, &cred->cr_group_info, rqstp)
770 	    == -EAGAIN)
771 		return SVC_DROP;
772 	if (cred->cr_group_info == NULL) {
773 		cred->cr_group_info = groups_alloc(slen);
774 		if (cred->cr_group_info == NULL)
775 			return SVC_DROP;
776 		for (i = 0; i < slen; i++)
777 			GROUP_AT(cred->cr_group_info, i) = svc_getnl(argv);
778 	} else {
779 		for (i = 0; i < slen ; i++)
780 			svc_getnl(argv);
781 	}
782 	if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) {
783 		*authp = rpc_autherr_badverf;
784 		return SVC_DENIED;
785 	}
786 
787 	/* Put NULL verifier */
788 	svc_putnl(resv, RPC_AUTH_NULL);
789 	svc_putnl(resv, 0);
790 
791 	rqstp->rq_flavor = RPC_AUTH_UNIX;
792 	return SVC_OK;
793 
794 badcred:
795 	*authp = rpc_autherr_badcred;
796 	return SVC_DENIED;
797 }
798 
799 static int
800 svcauth_unix_release(struct svc_rqst *rqstp)
801 {
802 	/* Verifier (such as it is) is already in place.
803 	 */
804 	if (rqstp->rq_client)
805 		auth_domain_put(rqstp->rq_client);
806 	rqstp->rq_client = NULL;
807 	if (rqstp->rq_cred.cr_group_info)
808 		put_group_info(rqstp->rq_cred.cr_group_info);
809 	rqstp->rq_cred.cr_group_info = NULL;
810 
811 	return 0;
812 }
813 
814 
815 struct auth_ops svcauth_unix = {
816 	.name		= "unix",
817 	.owner		= THIS_MODULE,
818 	.flavour	= RPC_AUTH_UNIX,
819 	.accept 	= svcauth_unix_accept,
820 	.release	= svcauth_unix_release,
821 	.domain_release	= svcauth_unix_domain_release,
822 	.set_client	= svcauth_unix_set_client,
823 };
824 
825