1 /*
2  * Neil Brown <neilb@cse.unsw.edu.au>
3  * J. Bruce Fields <bfields@umich.edu>
4  * Andy Adamson <andros@umich.edu>
5  * Dug Song <dugsong@monkey.org>
6  *
7  * RPCSEC_GSS server authentication.
8  * This implements RPCSEC_GSS as defined in rfc2203 (rpcsec_gss) and rfc2078
9  * (gssapi)
10  *
11  * The RPCSEC_GSS involves three stages:
12  *  1/ context creation
13  *  2/ data exchange
14  *  3/ context destruction
15  *
16  * Context creation is handled largely by upcalls to user-space.
17  *  In particular, GSS_Accept_sec_context is handled by an upcall
18  * Data exchange is handled entirely within the kernel
19  *  In particular, GSS_GetMIC, GSS_VerifyMIC, GSS_Seal, GSS_Unseal are in-kernel.
20  * Context destruction is handled in-kernel
21  *  GSS_Delete_sec_context is in-kernel
22  *
23  * Context creation is initiated by a RPCSEC_GSS_INIT request arriving.
24  * The context handle and gss_token are used as a key into the rpcsec_init cache.
25  * The content of this cache includes some of the outputs of GSS_Accept_sec_context,
26  * being major_status, minor_status, context_handle, reply_token.
27  * These are sent back to the client.
28  * Sequence window management is handled by the kernel.  The window size if currently
29  * a compile time constant.
30  *
31  * When user-space is happy that a context is established, it places an entry
32  * in the rpcsec_context cache. The key for this cache is the context_handle.
33  * The content includes:
34  *   uid/gidlist - for determining access rights
35  *   mechanism type
36  *   mechanism specific information, such as a key
37  *
38  */
39 
40 #include <linux/slab.h>
41 #include <linux/types.h>
42 #include <linux/module.h>
43 #include <linux/pagemap.h>
44 #include <linux/user_namespace.h>
45 
46 #include <linux/sunrpc/auth_gss.h>
47 #include <linux/sunrpc/gss_err.h>
48 #include <linux/sunrpc/svcauth.h>
49 #include <linux/sunrpc/svcauth_gss.h>
50 #include <linux/sunrpc/cache.h>
51 #include "gss_rpc_upcall.h"
52 
53 
54 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
55 # define RPCDBG_FACILITY	RPCDBG_AUTH
56 #endif
57 
58 /* The rpcsec_init cache is used for mapping RPCSEC_GSS_{,CONT_}INIT requests
59  * into replies.
60  *
61  * Key is context handle (\x if empty) and gss_token.
62  * Content is major_status minor_status (integers) context_handle, reply_token.
63  *
64  */
65 
66 static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b)
67 {
68 	return a->len == b->len && 0 == memcmp(a->data, b->data, a->len);
69 }
70 
71 #define	RSI_HASHBITS	6
72 #define	RSI_HASHMAX	(1<<RSI_HASHBITS)
73 
74 struct rsi {
75 	struct cache_head	h;
76 	struct xdr_netobj	in_handle, in_token;
77 	struct xdr_netobj	out_handle, out_token;
78 	int			major_status, minor_status;
79 };
80 
81 static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old);
82 static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item);
83 
84 static void rsi_free(struct rsi *rsii)
85 {
86 	kfree(rsii->in_handle.data);
87 	kfree(rsii->in_token.data);
88 	kfree(rsii->out_handle.data);
89 	kfree(rsii->out_token.data);
90 }
91 
92 static void rsi_put(struct kref *ref)
93 {
94 	struct rsi *rsii = container_of(ref, struct rsi, h.ref);
95 	rsi_free(rsii);
96 	kfree(rsii);
97 }
98 
99 static inline int rsi_hash(struct rsi *item)
100 {
101 	return hash_mem(item->in_handle.data, item->in_handle.len, RSI_HASHBITS)
102 	     ^ hash_mem(item->in_token.data, item->in_token.len, RSI_HASHBITS);
103 }
104 
105 static int rsi_match(struct cache_head *a, struct cache_head *b)
106 {
107 	struct rsi *item = container_of(a, struct rsi, h);
108 	struct rsi *tmp = container_of(b, struct rsi, h);
109 	return netobj_equal(&item->in_handle, &tmp->in_handle) &&
110 	       netobj_equal(&item->in_token, &tmp->in_token);
111 }
112 
113 static int dup_to_netobj(struct xdr_netobj *dst, char *src, int len)
114 {
115 	dst->len = len;
116 	dst->data = (len ? kmemdup(src, len, GFP_KERNEL) : NULL);
117 	if (len && !dst->data)
118 		return -ENOMEM;
119 	return 0;
120 }
121 
122 static inline int dup_netobj(struct xdr_netobj *dst, struct xdr_netobj *src)
123 {
124 	return dup_to_netobj(dst, src->data, src->len);
125 }
126 
127 static void rsi_init(struct cache_head *cnew, struct cache_head *citem)
128 {
129 	struct rsi *new = container_of(cnew, struct rsi, h);
130 	struct rsi *item = container_of(citem, struct rsi, h);
131 
132 	new->out_handle.data = NULL;
133 	new->out_handle.len = 0;
134 	new->out_token.data = NULL;
135 	new->out_token.len = 0;
136 	new->in_handle.len = item->in_handle.len;
137 	item->in_handle.len = 0;
138 	new->in_token.len = item->in_token.len;
139 	item->in_token.len = 0;
140 	new->in_handle.data = item->in_handle.data;
141 	item->in_handle.data = NULL;
142 	new->in_token.data = item->in_token.data;
143 	item->in_token.data = NULL;
144 }
145 
146 static void update_rsi(struct cache_head *cnew, struct cache_head *citem)
147 {
148 	struct rsi *new = container_of(cnew, struct rsi, h);
149 	struct rsi *item = container_of(citem, struct rsi, h);
150 
151 	BUG_ON(new->out_handle.data || new->out_token.data);
152 	new->out_handle.len = item->out_handle.len;
153 	item->out_handle.len = 0;
154 	new->out_token.len = item->out_token.len;
155 	item->out_token.len = 0;
156 	new->out_handle.data = item->out_handle.data;
157 	item->out_handle.data = NULL;
158 	new->out_token.data = item->out_token.data;
159 	item->out_token.data = NULL;
160 
161 	new->major_status = item->major_status;
162 	new->minor_status = item->minor_status;
163 }
164 
165 static struct cache_head *rsi_alloc(void)
166 {
167 	struct rsi *rsii = kmalloc(sizeof(*rsii), GFP_KERNEL);
168 	if (rsii)
169 		return &rsii->h;
170 	else
171 		return NULL;
172 }
173 
174 static void rsi_request(struct cache_detail *cd,
175 		       struct cache_head *h,
176 		       char **bpp, int *blen)
177 {
178 	struct rsi *rsii = container_of(h, struct rsi, h);
179 
180 	qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len);
181 	qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len);
182 	(*bpp)[-1] = '\n';
183 }
184 
185 static int rsi_parse(struct cache_detail *cd,
186 		    char *mesg, int mlen)
187 {
188 	/* context token expiry major minor context token */
189 	char *buf = mesg;
190 	char *ep;
191 	int len;
192 	struct rsi rsii, *rsip = NULL;
193 	time_t expiry;
194 	int status = -EINVAL;
195 
196 	memset(&rsii, 0, sizeof(rsii));
197 	/* handle */
198 	len = qword_get(&mesg, buf, mlen);
199 	if (len < 0)
200 		goto out;
201 	status = -ENOMEM;
202 	if (dup_to_netobj(&rsii.in_handle, buf, len))
203 		goto out;
204 
205 	/* token */
206 	len = qword_get(&mesg, buf, mlen);
207 	status = -EINVAL;
208 	if (len < 0)
209 		goto out;
210 	status = -ENOMEM;
211 	if (dup_to_netobj(&rsii.in_token, buf, len))
212 		goto out;
213 
214 	rsip = rsi_lookup(cd, &rsii);
215 	if (!rsip)
216 		goto out;
217 
218 	rsii.h.flags = 0;
219 	/* expiry */
220 	expiry = get_expiry(&mesg);
221 	status = -EINVAL;
222 	if (expiry == 0)
223 		goto out;
224 
225 	/* major/minor */
226 	len = qword_get(&mesg, buf, mlen);
227 	if (len <= 0)
228 		goto out;
229 	rsii.major_status = simple_strtoul(buf, &ep, 10);
230 	if (*ep)
231 		goto out;
232 	len = qword_get(&mesg, buf, mlen);
233 	if (len <= 0)
234 		goto out;
235 	rsii.minor_status = simple_strtoul(buf, &ep, 10);
236 	if (*ep)
237 		goto out;
238 
239 	/* out_handle */
240 	len = qword_get(&mesg, buf, mlen);
241 	if (len < 0)
242 		goto out;
243 	status = -ENOMEM;
244 	if (dup_to_netobj(&rsii.out_handle, buf, len))
245 		goto out;
246 
247 	/* out_token */
248 	len = qword_get(&mesg, buf, mlen);
249 	status = -EINVAL;
250 	if (len < 0)
251 		goto out;
252 	status = -ENOMEM;
253 	if (dup_to_netobj(&rsii.out_token, buf, len))
254 		goto out;
255 	rsii.h.expiry_time = expiry;
256 	rsip = rsi_update(cd, &rsii, rsip);
257 	status = 0;
258 out:
259 	rsi_free(&rsii);
260 	if (rsip)
261 		cache_put(&rsip->h, cd);
262 	else
263 		status = -ENOMEM;
264 	return status;
265 }
266 
267 static const struct cache_detail rsi_cache_template = {
268 	.owner		= THIS_MODULE,
269 	.hash_size	= RSI_HASHMAX,
270 	.name           = "auth.rpcsec.init",
271 	.cache_put      = rsi_put,
272 	.cache_request  = rsi_request,
273 	.cache_parse    = rsi_parse,
274 	.match		= rsi_match,
275 	.init		= rsi_init,
276 	.update		= update_rsi,
277 	.alloc		= rsi_alloc,
278 };
279 
280 static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item)
281 {
282 	struct cache_head *ch;
283 	int hash = rsi_hash(item);
284 
285 	ch = sunrpc_cache_lookup(cd, &item->h, hash);
286 	if (ch)
287 		return container_of(ch, struct rsi, h);
288 	else
289 		return NULL;
290 }
291 
292 static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old)
293 {
294 	struct cache_head *ch;
295 	int hash = rsi_hash(new);
296 
297 	ch = sunrpc_cache_update(cd, &new->h,
298 				 &old->h, hash);
299 	if (ch)
300 		return container_of(ch, struct rsi, h);
301 	else
302 		return NULL;
303 }
304 
305 
306 /*
307  * The rpcsec_context cache is used to store a context that is
308  * used in data exchange.
309  * The key is a context handle. The content is:
310  *  uid, gidlist, mechanism, service-set, mech-specific-data
311  */
312 
313 #define	RSC_HASHBITS	10
314 #define	RSC_HASHMAX	(1<<RSC_HASHBITS)
315 
316 #define GSS_SEQ_WIN	128
317 
318 struct gss_svc_seq_data {
319 	/* highest seq number seen so far: */
320 	int			sd_max;
321 	/* for i such that sd_max-GSS_SEQ_WIN < i <= sd_max, the i-th bit of
322 	 * sd_win is nonzero iff sequence number i has been seen already: */
323 	unsigned long		sd_win[GSS_SEQ_WIN/BITS_PER_LONG];
324 	spinlock_t		sd_lock;
325 };
326 
327 struct rsc {
328 	struct cache_head	h;
329 	struct xdr_netobj	handle;
330 	struct svc_cred		cred;
331 	struct gss_svc_seq_data	seqdata;
332 	struct gss_ctx		*mechctx;
333 };
334 
335 static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old);
336 static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item);
337 
338 static void rsc_free(struct rsc *rsci)
339 {
340 	kfree(rsci->handle.data);
341 	if (rsci->mechctx)
342 		gss_delete_sec_context(&rsci->mechctx);
343 	free_svc_cred(&rsci->cred);
344 }
345 
346 static void rsc_put(struct kref *ref)
347 {
348 	struct rsc *rsci = container_of(ref, struct rsc, h.ref);
349 
350 	rsc_free(rsci);
351 	kfree(rsci);
352 }
353 
354 static inline int
355 rsc_hash(struct rsc *rsci)
356 {
357 	return hash_mem(rsci->handle.data, rsci->handle.len, RSC_HASHBITS);
358 }
359 
360 static int
361 rsc_match(struct cache_head *a, struct cache_head *b)
362 {
363 	struct rsc *new = container_of(a, struct rsc, h);
364 	struct rsc *tmp = container_of(b, struct rsc, h);
365 
366 	return netobj_equal(&new->handle, &tmp->handle);
367 }
368 
369 static void
370 rsc_init(struct cache_head *cnew, struct cache_head *ctmp)
371 {
372 	struct rsc *new = container_of(cnew, struct rsc, h);
373 	struct rsc *tmp = container_of(ctmp, struct rsc, h);
374 
375 	new->handle.len = tmp->handle.len;
376 	tmp->handle.len = 0;
377 	new->handle.data = tmp->handle.data;
378 	tmp->handle.data = NULL;
379 	new->mechctx = NULL;
380 	init_svc_cred(&new->cred);
381 }
382 
383 static void
384 update_rsc(struct cache_head *cnew, struct cache_head *ctmp)
385 {
386 	struct rsc *new = container_of(cnew, struct rsc, h);
387 	struct rsc *tmp = container_of(ctmp, struct rsc, h);
388 
389 	new->mechctx = tmp->mechctx;
390 	tmp->mechctx = NULL;
391 	memset(&new->seqdata, 0, sizeof(new->seqdata));
392 	spin_lock_init(&new->seqdata.sd_lock);
393 	new->cred = tmp->cred;
394 	init_svc_cred(&tmp->cred);
395 }
396 
397 static struct cache_head *
398 rsc_alloc(void)
399 {
400 	struct rsc *rsci = kmalloc(sizeof(*rsci), GFP_KERNEL);
401 	if (rsci)
402 		return &rsci->h;
403 	else
404 		return NULL;
405 }
406 
407 static int rsc_parse(struct cache_detail *cd,
408 		     char *mesg, int mlen)
409 {
410 	/* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */
411 	char *buf = mesg;
412 	int id;
413 	int len, rv;
414 	struct rsc rsci, *rscp = NULL;
415 	time_t expiry;
416 	int status = -EINVAL;
417 	struct gss_api_mech *gm = NULL;
418 
419 	memset(&rsci, 0, sizeof(rsci));
420 	/* context handle */
421 	len = qword_get(&mesg, buf, mlen);
422 	if (len < 0) goto out;
423 	status = -ENOMEM;
424 	if (dup_to_netobj(&rsci.handle, buf, len))
425 		goto out;
426 
427 	rsci.h.flags = 0;
428 	/* expiry */
429 	expiry = get_expiry(&mesg);
430 	status = -EINVAL;
431 	if (expiry == 0)
432 		goto out;
433 
434 	rscp = rsc_lookup(cd, &rsci);
435 	if (!rscp)
436 		goto out;
437 
438 	/* uid, or NEGATIVE */
439 	rv = get_int(&mesg, &id);
440 	if (rv == -EINVAL)
441 		goto out;
442 	if (rv == -ENOENT)
443 		set_bit(CACHE_NEGATIVE, &rsci.h.flags);
444 	else {
445 		int N, i;
446 
447 		/*
448 		 * NOTE: we skip uid_valid()/gid_valid() checks here:
449 		 * instead, * -1 id's are later mapped to the
450 		 * (export-specific) anonymous id by nfsd_setuser.
451 		 *
452 		 * (But supplementary gid's get no such special
453 		 * treatment so are checked for validity here.)
454 		 */
455 		/* uid */
456 		rsci.cred.cr_uid = make_kuid(&init_user_ns, id);
457 
458 		/* gid */
459 		if (get_int(&mesg, &id))
460 			goto out;
461 		rsci.cred.cr_gid = make_kgid(&init_user_ns, id);
462 
463 		/* number of additional gid's */
464 		if (get_int(&mesg, &N))
465 			goto out;
466 		if (N < 0 || N > NGROUPS_MAX)
467 			goto out;
468 		status = -ENOMEM;
469 		rsci.cred.cr_group_info = groups_alloc(N);
470 		if (rsci.cred.cr_group_info == NULL)
471 			goto out;
472 
473 		/* gid's */
474 		status = -EINVAL;
475 		for (i=0; i<N; i++) {
476 			kgid_t kgid;
477 			if (get_int(&mesg, &id))
478 				goto out;
479 			kgid = make_kgid(&init_user_ns, id);
480 			if (!gid_valid(kgid))
481 				goto out;
482 			rsci.cred.cr_group_info->gid[i] = kgid;
483 		}
484 		groups_sort(rsci.cred.cr_group_info);
485 
486 		/* mech name */
487 		len = qword_get(&mesg, buf, mlen);
488 		if (len < 0)
489 			goto out;
490 		gm = rsci.cred.cr_gss_mech = gss_mech_get_by_name(buf);
491 		status = -EOPNOTSUPP;
492 		if (!gm)
493 			goto out;
494 
495 		status = -EINVAL;
496 		/* mech-specific data: */
497 		len = qword_get(&mesg, buf, mlen);
498 		if (len < 0)
499 			goto out;
500 		status = gss_import_sec_context(buf, len, gm, &rsci.mechctx,
501 						NULL, GFP_KERNEL);
502 		if (status)
503 			goto out;
504 
505 		/* get client name */
506 		len = qword_get(&mesg, buf, mlen);
507 		if (len > 0) {
508 			rsci.cred.cr_principal = kstrdup(buf, GFP_KERNEL);
509 			if (!rsci.cred.cr_principal) {
510 				status = -ENOMEM;
511 				goto out;
512 			}
513 		}
514 
515 	}
516 	rsci.h.expiry_time = expiry;
517 	rscp = rsc_update(cd, &rsci, rscp);
518 	status = 0;
519 out:
520 	rsc_free(&rsci);
521 	if (rscp)
522 		cache_put(&rscp->h, cd);
523 	else
524 		status = -ENOMEM;
525 	return status;
526 }
527 
528 static const struct cache_detail rsc_cache_template = {
529 	.owner		= THIS_MODULE,
530 	.hash_size	= RSC_HASHMAX,
531 	.name		= "auth.rpcsec.context",
532 	.cache_put	= rsc_put,
533 	.cache_parse	= rsc_parse,
534 	.match		= rsc_match,
535 	.init		= rsc_init,
536 	.update		= update_rsc,
537 	.alloc		= rsc_alloc,
538 };
539 
540 static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item)
541 {
542 	struct cache_head *ch;
543 	int hash = rsc_hash(item);
544 
545 	ch = sunrpc_cache_lookup(cd, &item->h, hash);
546 	if (ch)
547 		return container_of(ch, struct rsc, h);
548 	else
549 		return NULL;
550 }
551 
552 static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old)
553 {
554 	struct cache_head *ch;
555 	int hash = rsc_hash(new);
556 
557 	ch = sunrpc_cache_update(cd, &new->h,
558 				 &old->h, hash);
559 	if (ch)
560 		return container_of(ch, struct rsc, h);
561 	else
562 		return NULL;
563 }
564 
565 
566 static struct rsc *
567 gss_svc_searchbyctx(struct cache_detail *cd, struct xdr_netobj *handle)
568 {
569 	struct rsc rsci;
570 	struct rsc *found;
571 
572 	memset(&rsci, 0, sizeof(rsci));
573 	if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
574 		return NULL;
575 	found = rsc_lookup(cd, &rsci);
576 	rsc_free(&rsci);
577 	if (!found)
578 		return NULL;
579 	if (cache_check(cd, &found->h, NULL))
580 		return NULL;
581 	return found;
582 }
583 
584 /* Implements sequence number algorithm as specified in RFC 2203. */
585 static int
586 gss_check_seq_num(struct rsc *rsci, int seq_num)
587 {
588 	struct gss_svc_seq_data *sd = &rsci->seqdata;
589 
590 	spin_lock(&sd->sd_lock);
591 	if (seq_num > sd->sd_max) {
592 		if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
593 			memset(sd->sd_win,0,sizeof(sd->sd_win));
594 			sd->sd_max = seq_num;
595 		} else while (sd->sd_max < seq_num) {
596 			sd->sd_max++;
597 			__clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
598 		}
599 		__set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
600 		goto ok;
601 	} else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) {
602 		goto drop;
603 	}
604 	/* sd_max - GSS_SEQ_WIN < seq_num <= sd_max */
605 	if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
606 		goto drop;
607 ok:
608 	spin_unlock(&sd->sd_lock);
609 	return 1;
610 drop:
611 	spin_unlock(&sd->sd_lock);
612 	return 0;
613 }
614 
615 static inline u32 round_up_to_quad(u32 i)
616 {
617 	return (i + 3 ) & ~3;
618 }
619 
620 static inline int
621 svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o)
622 {
623 	int l;
624 
625 	if (argv->iov_len < 4)
626 		return -1;
627 	o->len = svc_getnl(argv);
628 	l = round_up_to_quad(o->len);
629 	if (argv->iov_len < l)
630 		return -1;
631 	o->data = argv->iov_base;
632 	argv->iov_base += l;
633 	argv->iov_len -= l;
634 	return 0;
635 }
636 
637 static inline int
638 svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
639 {
640 	u8 *p;
641 
642 	if (resv->iov_len + 4 > PAGE_SIZE)
643 		return -1;
644 	svc_putnl(resv, o->len);
645 	p = resv->iov_base + resv->iov_len;
646 	resv->iov_len += round_up_to_quad(o->len);
647 	if (resv->iov_len > PAGE_SIZE)
648 		return -1;
649 	memcpy(p, o->data, o->len);
650 	memset(p + o->len, 0, round_up_to_quad(o->len) - o->len);
651 	return 0;
652 }
653 
654 /*
655  * Verify the checksum on the header and return SVC_OK on success.
656  * Otherwise, return SVC_DROP (in the case of a bad sequence number)
657  * or return SVC_DENIED and indicate error in authp.
658  */
659 static int
660 gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
661 		  __be32 *rpcstart, struct rpc_gss_wire_cred *gc, __be32 *authp)
662 {
663 	struct gss_ctx		*ctx_id = rsci->mechctx;
664 	struct xdr_buf		rpchdr;
665 	struct xdr_netobj	checksum;
666 	u32			flavor = 0;
667 	struct kvec		*argv = &rqstp->rq_arg.head[0];
668 	struct kvec		iov;
669 
670 	/* data to compute the checksum over: */
671 	iov.iov_base = rpcstart;
672 	iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart;
673 	xdr_buf_from_iov(&iov, &rpchdr);
674 
675 	*authp = rpc_autherr_badverf;
676 	if (argv->iov_len < 4)
677 		return SVC_DENIED;
678 	flavor = svc_getnl(argv);
679 	if (flavor != RPC_AUTH_GSS)
680 		return SVC_DENIED;
681 	if (svc_safe_getnetobj(argv, &checksum))
682 		return SVC_DENIED;
683 
684 	if (rqstp->rq_deferred) /* skip verification of revisited request */
685 		return SVC_OK;
686 	if (gss_verify_mic(ctx_id, &rpchdr, &checksum) != GSS_S_COMPLETE) {
687 		*authp = rpcsec_gsserr_credproblem;
688 		return SVC_DENIED;
689 	}
690 
691 	if (gc->gc_seq > MAXSEQ) {
692 		dprintk("RPC:       svcauth_gss: discarding request with "
693 				"large sequence number %d\n", gc->gc_seq);
694 		*authp = rpcsec_gsserr_ctxproblem;
695 		return SVC_DENIED;
696 	}
697 	if (!gss_check_seq_num(rsci, gc->gc_seq)) {
698 		dprintk("RPC:       svcauth_gss: discarding request with "
699 				"old sequence number %d\n", gc->gc_seq);
700 		return SVC_DROP;
701 	}
702 	return SVC_OK;
703 }
704 
705 static int
706 gss_write_null_verf(struct svc_rqst *rqstp)
707 {
708 	__be32     *p;
709 
710 	svc_putnl(rqstp->rq_res.head, RPC_AUTH_NULL);
711 	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
712 	/* don't really need to check if head->iov_len > PAGE_SIZE ... */
713 	*p++ = 0;
714 	if (!xdr_ressize_check(rqstp, p))
715 		return -1;
716 	return 0;
717 }
718 
719 static int
720 gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
721 {
722 	__be32			*xdr_seq;
723 	u32			maj_stat;
724 	struct xdr_buf		verf_data;
725 	struct xdr_netobj	mic;
726 	__be32			*p;
727 	struct kvec		iov;
728 	int err = -1;
729 
730 	svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
731 	xdr_seq = kmalloc(4, GFP_KERNEL);
732 	if (!xdr_seq)
733 		return -1;
734 	*xdr_seq = htonl(seq);
735 
736 	iov.iov_base = xdr_seq;
737 	iov.iov_len = 4;
738 	xdr_buf_from_iov(&iov, &verf_data);
739 	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
740 	mic.data = (u8 *)(p + 1);
741 	maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
742 	if (maj_stat != GSS_S_COMPLETE)
743 		goto out;
744 	*p++ = htonl(mic.len);
745 	memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
746 	p += XDR_QUADLEN(mic.len);
747 	if (!xdr_ressize_check(rqstp, p))
748 		goto out;
749 	err = 0;
750 out:
751 	kfree(xdr_seq);
752 	return err;
753 }
754 
755 struct gss_domain {
756 	struct auth_domain	h;
757 	u32			pseudoflavor;
758 };
759 
760 static struct auth_domain *
761 find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
762 {
763 	char *name;
764 
765 	name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
766 	if (!name)
767 		return NULL;
768 	return auth_domain_find(name);
769 }
770 
771 static struct auth_ops svcauthops_gss;
772 
773 u32 svcauth_gss_flavor(struct auth_domain *dom)
774 {
775 	struct gss_domain *gd = container_of(dom, struct gss_domain, h);
776 
777 	return gd->pseudoflavor;
778 }
779 
780 EXPORT_SYMBOL_GPL(svcauth_gss_flavor);
781 
782 int
783 svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
784 {
785 	struct gss_domain	*new;
786 	struct auth_domain	*test;
787 	int			stat = -ENOMEM;
788 
789 	new = kmalloc(sizeof(*new), GFP_KERNEL);
790 	if (!new)
791 		goto out;
792 	kref_init(&new->h.ref);
793 	new->h.name = kstrdup(name, GFP_KERNEL);
794 	if (!new->h.name)
795 		goto out_free_dom;
796 	new->h.flavour = &svcauthops_gss;
797 	new->pseudoflavor = pseudoflavor;
798 
799 	stat = 0;
800 	test = auth_domain_lookup(name, &new->h);
801 	if (test != &new->h) { /* Duplicate registration */
802 		auth_domain_put(test);
803 		kfree(new->h.name);
804 		goto out_free_dom;
805 	}
806 	return 0;
807 
808 out_free_dom:
809 	kfree(new);
810 out:
811 	return stat;
812 }
813 
814 EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor);
815 
816 static inline int
817 read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
818 {
819 	__be32  raw;
820 	int     status;
821 
822 	status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
823 	if (status)
824 		return status;
825 	*obj = ntohl(raw);
826 	return 0;
827 }
828 
829 /* It would be nice if this bit of code could be shared with the client.
830  * Obstacles:
831  *	The client shouldn't malloc(), would have to pass in own memory.
832  *	The server uses base of head iovec as read pointer, while the
833  *	client uses separate pointer. */
834 static int
835 unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
836 {
837 	int stat = -EINVAL;
838 	u32 integ_len, maj_stat;
839 	struct xdr_netobj mic;
840 	struct xdr_buf integ_buf;
841 
842 	/* NFS READ normally uses splice to send data in-place. However
843 	 * the data in cache can change after the reply's MIC is computed
844 	 * but before the RPC reply is sent. To prevent the client from
845 	 * rejecting the server-computed MIC in this somewhat rare case,
846 	 * do not use splice with the GSS integrity service.
847 	 */
848 	clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
849 
850 	/* Did we already verify the signature on the original pass through? */
851 	if (rqstp->rq_deferred)
852 		return 0;
853 
854 	integ_len = svc_getnl(&buf->head[0]);
855 	if (integ_len & 3)
856 		return stat;
857 	if (integ_len > buf->len)
858 		return stat;
859 	if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len)) {
860 		WARN_ON_ONCE(1);
861 		return stat;
862 	}
863 	/* copy out mic... */
864 	if (read_u32_from_xdr_buf(buf, integ_len, &mic.len))
865 		return stat;
866 	if (mic.len > RPC_MAX_AUTH_SIZE)
867 		return stat;
868 	mic.data = kmalloc(mic.len, GFP_KERNEL);
869 	if (!mic.data)
870 		return stat;
871 	if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len))
872 		goto out;
873 	maj_stat = gss_verify_mic(ctx, &integ_buf, &mic);
874 	if (maj_stat != GSS_S_COMPLETE)
875 		goto out;
876 	if (svc_getnl(&buf->head[0]) != seq)
877 		goto out;
878 	/* trim off the mic and padding at the end before returning */
879 	xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4);
880 	stat = 0;
881 out:
882 	kfree(mic.data);
883 	return stat;
884 }
885 
886 static inline int
887 total_buf_len(struct xdr_buf *buf)
888 {
889 	return buf->head[0].iov_len + buf->page_len + buf->tail[0].iov_len;
890 }
891 
892 static void
893 fix_priv_head(struct xdr_buf *buf, int pad)
894 {
895 	if (buf->page_len == 0) {
896 		/* We need to adjust head and buf->len in tandem in this
897 		 * case to make svc_defer() work--it finds the original
898 		 * buffer start using buf->len - buf->head[0].iov_len. */
899 		buf->head[0].iov_len -= pad;
900 	}
901 }
902 
903 static int
904 unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
905 {
906 	u32 priv_len, maj_stat;
907 	int pad, saved_len, remaining_len, offset;
908 
909 	clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
910 
911 	priv_len = svc_getnl(&buf->head[0]);
912 	if (rqstp->rq_deferred) {
913 		/* Already decrypted last time through! The sequence number
914 		 * check at out_seq is unnecessary but harmless: */
915 		goto out_seq;
916 	}
917 	/* buf->len is the number of bytes from the original start of the
918 	 * request to the end, where head[0].iov_len is just the bytes
919 	 * not yet read from the head, so these two values are different: */
920 	remaining_len = total_buf_len(buf);
921 	if (priv_len > remaining_len)
922 		return -EINVAL;
923 	pad = remaining_len - priv_len;
924 	buf->len -= pad;
925 	fix_priv_head(buf, pad);
926 
927 	/* Maybe it would be better to give gss_unwrap a length parameter: */
928 	saved_len = buf->len;
929 	buf->len = priv_len;
930 	maj_stat = gss_unwrap(ctx, 0, buf);
931 	pad = priv_len - buf->len;
932 	buf->len = saved_len;
933 	buf->len -= pad;
934 	/* The upper layers assume the buffer is aligned on 4-byte boundaries.
935 	 * In the krb5p case, at least, the data ends up offset, so we need to
936 	 * move it around. */
937 	/* XXX: This is very inefficient.  It would be better to either do
938 	 * this while we encrypt, or maybe in the receive code, if we can peak
939 	 * ahead and work out the service and mechanism there. */
940 	offset = buf->head[0].iov_len % 4;
941 	if (offset) {
942 		buf->buflen = RPCSVC_MAXPAYLOAD;
943 		xdr_shift_buf(buf, offset);
944 		fix_priv_head(buf, pad);
945 	}
946 	if (maj_stat != GSS_S_COMPLETE)
947 		return -EINVAL;
948 out_seq:
949 	if (svc_getnl(&buf->head[0]) != seq)
950 		return -EINVAL;
951 	return 0;
952 }
953 
954 struct gss_svc_data {
955 	/* decoded gss client cred: */
956 	struct rpc_gss_wire_cred	clcred;
957 	/* save a pointer to the beginning of the encoded verifier,
958 	 * for use in encryption/checksumming in svcauth_gss_release: */
959 	__be32				*verf_start;
960 	struct rsc			*rsci;
961 };
962 
963 static int
964 svcauth_gss_set_client(struct svc_rqst *rqstp)
965 {
966 	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
967 	struct rsc *rsci = svcdata->rsci;
968 	struct rpc_gss_wire_cred *gc = &svcdata->clcred;
969 	int stat;
970 
971 	/*
972 	 * A gss export can be specified either by:
973 	 * 	export	*(sec=krb5,rw)
974 	 * or by
975 	 * 	export gss/krb5(rw)
976 	 * The latter is deprecated; but for backwards compatibility reasons
977 	 * the nfsd code will still fall back on trying it if the former
978 	 * doesn't work; so we try to make both available to nfsd, below.
979 	 */
980 	rqstp->rq_gssclient = find_gss_auth_domain(rsci->mechctx, gc->gc_svc);
981 	if (rqstp->rq_gssclient == NULL)
982 		return SVC_DENIED;
983 	stat = svcauth_unix_set_client(rqstp);
984 	if (stat == SVC_DROP || stat == SVC_CLOSE)
985 		return stat;
986 	return SVC_OK;
987 }
988 
989 static inline int
990 gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,
991 		struct xdr_netobj *out_handle, int *major_status)
992 {
993 	struct rsc *rsci;
994 	int        rc;
995 
996 	if (*major_status != GSS_S_COMPLETE)
997 		return gss_write_null_verf(rqstp);
998 	rsci = gss_svc_searchbyctx(cd, out_handle);
999 	if (rsci == NULL) {
1000 		*major_status = GSS_S_NO_CONTEXT;
1001 		return gss_write_null_verf(rqstp);
1002 	}
1003 	rc = gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN);
1004 	cache_put(&rsci->h, cd);
1005 	return rc;
1006 }
1007 
1008 static inline int
1009 gss_read_common_verf(struct rpc_gss_wire_cred *gc,
1010 		     struct kvec *argv, __be32 *authp,
1011 		     struct xdr_netobj *in_handle)
1012 {
1013 	/* Read the verifier; should be NULL: */
1014 	*authp = rpc_autherr_badverf;
1015 	if (argv->iov_len < 2 * 4)
1016 		return SVC_DENIED;
1017 	if (svc_getnl(argv) != RPC_AUTH_NULL)
1018 		return SVC_DENIED;
1019 	if (svc_getnl(argv) != 0)
1020 		return SVC_DENIED;
1021 	/* Martial context handle and token for upcall: */
1022 	*authp = rpc_autherr_badcred;
1023 	if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
1024 		return SVC_DENIED;
1025 	if (dup_netobj(in_handle, &gc->gc_ctx))
1026 		return SVC_CLOSE;
1027 	*authp = rpc_autherr_badverf;
1028 
1029 	return 0;
1030 }
1031 
1032 static inline int
1033 gss_read_verf(struct rpc_gss_wire_cred *gc,
1034 	      struct kvec *argv, __be32 *authp,
1035 	      struct xdr_netobj *in_handle,
1036 	      struct xdr_netobj *in_token)
1037 {
1038 	struct xdr_netobj tmpobj;
1039 	int res;
1040 
1041 	res = gss_read_common_verf(gc, argv, authp, in_handle);
1042 	if (res)
1043 		return res;
1044 
1045 	if (svc_safe_getnetobj(argv, &tmpobj)) {
1046 		kfree(in_handle->data);
1047 		return SVC_DENIED;
1048 	}
1049 	if (dup_netobj(in_token, &tmpobj)) {
1050 		kfree(in_handle->data);
1051 		return SVC_CLOSE;
1052 	}
1053 
1054 	return 0;
1055 }
1056 
1057 /* Ok this is really heavily depending on a set of semantics in
1058  * how rqstp is set up by svc_recv and pages laid down by the
1059  * server when reading a request. We are basically guaranteed that
1060  * the token lays all down linearly across a set of pages, starting
1061  * at iov_base in rq_arg.head[0] which happens to be the first of a
1062  * set of pages stored in rq_pages[].
1063  * rq_arg.head[0].iov_base will provide us the page_base to pass
1064  * to the upcall.
1065  */
1066 static inline int
1067 gss_read_proxy_verf(struct svc_rqst *rqstp,
1068 		    struct rpc_gss_wire_cred *gc, __be32 *authp,
1069 		    struct xdr_netobj *in_handle,
1070 		    struct gssp_in_token *in_token)
1071 {
1072 	struct kvec *argv = &rqstp->rq_arg.head[0];
1073 	u32 inlen;
1074 	int res;
1075 
1076 	res = gss_read_common_verf(gc, argv, authp, in_handle);
1077 	if (res)
1078 		return res;
1079 
1080 	inlen = svc_getnl(argv);
1081 	if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
1082 		return SVC_DENIED;
1083 
1084 	in_token->pages = rqstp->rq_pages;
1085 	in_token->page_base = (ulong)argv->iov_base & ~PAGE_MASK;
1086 	in_token->page_len = inlen;
1087 
1088 	return 0;
1089 }
1090 
1091 static inline int
1092 gss_write_resv(struct kvec *resv, size_t size_limit,
1093 	       struct xdr_netobj *out_handle, struct xdr_netobj *out_token,
1094 	       int major_status, int minor_status)
1095 {
1096 	if (resv->iov_len + 4 > size_limit)
1097 		return -1;
1098 	svc_putnl(resv, RPC_SUCCESS);
1099 	if (svc_safe_putnetobj(resv, out_handle))
1100 		return -1;
1101 	if (resv->iov_len + 3 * 4 > size_limit)
1102 		return -1;
1103 	svc_putnl(resv, major_status);
1104 	svc_putnl(resv, minor_status);
1105 	svc_putnl(resv, GSS_SEQ_WIN);
1106 	if (svc_safe_putnetobj(resv, out_token))
1107 		return -1;
1108 	return 0;
1109 }
1110 
1111 /*
1112  * Having read the cred already and found we're in the context
1113  * initiation case, read the verifier and initiate (or check the results
1114  * of) upcalls to userspace for help with context initiation.  If
1115  * the upcall results are available, write the verifier and result.
1116  * Otherwise, drop the request pending an answer to the upcall.
1117  */
1118 static int svcauth_gss_legacy_init(struct svc_rqst *rqstp,
1119 			struct rpc_gss_wire_cred *gc, __be32 *authp)
1120 {
1121 	struct kvec *argv = &rqstp->rq_arg.head[0];
1122 	struct kvec *resv = &rqstp->rq_res.head[0];
1123 	struct rsi *rsip, rsikey;
1124 	int ret;
1125 	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1126 
1127 	memset(&rsikey, 0, sizeof(rsikey));
1128 	ret = gss_read_verf(gc, argv, authp,
1129 			    &rsikey.in_handle, &rsikey.in_token);
1130 	if (ret)
1131 		return ret;
1132 
1133 	/* Perform upcall, or find upcall result: */
1134 	rsip = rsi_lookup(sn->rsi_cache, &rsikey);
1135 	rsi_free(&rsikey);
1136 	if (!rsip)
1137 		return SVC_CLOSE;
1138 	if (cache_check(sn->rsi_cache, &rsip->h, &rqstp->rq_chandle) < 0)
1139 		/* No upcall result: */
1140 		return SVC_CLOSE;
1141 
1142 	ret = SVC_CLOSE;
1143 	/* Got an answer to the upcall; use it: */
1144 	if (gss_write_init_verf(sn->rsc_cache, rqstp,
1145 				&rsip->out_handle, &rsip->major_status))
1146 		goto out;
1147 	if (gss_write_resv(resv, PAGE_SIZE,
1148 			   &rsip->out_handle, &rsip->out_token,
1149 			   rsip->major_status, rsip->minor_status))
1150 		goto out;
1151 
1152 	ret = SVC_COMPLETE;
1153 out:
1154 	cache_put(&rsip->h, sn->rsi_cache);
1155 	return ret;
1156 }
1157 
1158 static int gss_proxy_save_rsc(struct cache_detail *cd,
1159 				struct gssp_upcall_data *ud,
1160 				uint64_t *handle)
1161 {
1162 	struct rsc rsci, *rscp = NULL;
1163 	static atomic64_t ctxhctr;
1164 	long long ctxh;
1165 	struct gss_api_mech *gm = NULL;
1166 	time_t expiry;
1167 	int status = -EINVAL;
1168 
1169 	memset(&rsci, 0, sizeof(rsci));
1170 	/* context handle */
1171 	status = -ENOMEM;
1172 	/* the handle needs to be just a unique id,
1173 	 * use a static counter */
1174 	ctxh = atomic64_inc_return(&ctxhctr);
1175 
1176 	/* make a copy for the caller */
1177 	*handle = ctxh;
1178 
1179 	/* make a copy for the rsc cache */
1180 	if (dup_to_netobj(&rsci.handle, (char *)handle, sizeof(uint64_t)))
1181 		goto out;
1182 	rscp = rsc_lookup(cd, &rsci);
1183 	if (!rscp)
1184 		goto out;
1185 
1186 	/* creds */
1187 	if (!ud->found_creds) {
1188 		/* userspace seem buggy, we should always get at least a
1189 		 * mapping to nobody */
1190 		dprintk("RPC:       No creds found!\n");
1191 		goto out;
1192 	} else {
1193 
1194 		/* steal creds */
1195 		rsci.cred = ud->creds;
1196 		memset(&ud->creds, 0, sizeof(struct svc_cred));
1197 
1198 		status = -EOPNOTSUPP;
1199 		/* get mech handle from OID */
1200 		gm = gss_mech_get_by_OID(&ud->mech_oid);
1201 		if (!gm)
1202 			goto out;
1203 		rsci.cred.cr_gss_mech = gm;
1204 
1205 		status = -EINVAL;
1206 		/* mech-specific data: */
1207 		status = gss_import_sec_context(ud->out_handle.data,
1208 						ud->out_handle.len,
1209 						gm, &rsci.mechctx,
1210 						&expiry, GFP_KERNEL);
1211 		if (status)
1212 			goto out;
1213 	}
1214 
1215 	rsci.h.expiry_time = expiry;
1216 	rscp = rsc_update(cd, &rsci, rscp);
1217 	status = 0;
1218 out:
1219 	rsc_free(&rsci);
1220 	if (rscp)
1221 		cache_put(&rscp->h, cd);
1222 	else
1223 		status = -ENOMEM;
1224 	return status;
1225 }
1226 
1227 static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
1228 			struct rpc_gss_wire_cred *gc, __be32 *authp)
1229 {
1230 	struct kvec *resv = &rqstp->rq_res.head[0];
1231 	struct xdr_netobj cli_handle;
1232 	struct gssp_upcall_data ud;
1233 	uint64_t handle;
1234 	int status;
1235 	int ret;
1236 	struct net *net = rqstp->rq_xprt->xpt_net;
1237 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1238 
1239 	memset(&ud, 0, sizeof(ud));
1240 	ret = gss_read_proxy_verf(rqstp, gc, authp,
1241 				  &ud.in_handle, &ud.in_token);
1242 	if (ret)
1243 		return ret;
1244 
1245 	ret = SVC_CLOSE;
1246 
1247 	/* Perform synchronous upcall to gss-proxy */
1248 	status = gssp_accept_sec_context_upcall(net, &ud);
1249 	if (status)
1250 		goto out;
1251 
1252 	dprintk("RPC:       svcauth_gss: gss major status = %d "
1253 			"minor status = %d\n",
1254 			ud.major_status, ud.minor_status);
1255 
1256 	switch (ud.major_status) {
1257 	case GSS_S_CONTINUE_NEEDED:
1258 		cli_handle = ud.out_handle;
1259 		break;
1260 	case GSS_S_COMPLETE:
1261 		status = gss_proxy_save_rsc(sn->rsc_cache, &ud, &handle);
1262 		if (status)
1263 			goto out;
1264 		cli_handle.data = (u8 *)&handle;
1265 		cli_handle.len = sizeof(handle);
1266 		break;
1267 	default:
1268 		ret = SVC_CLOSE;
1269 		goto out;
1270 	}
1271 
1272 	/* Got an answer to the upcall; use it: */
1273 	if (gss_write_init_verf(sn->rsc_cache, rqstp,
1274 				&cli_handle, &ud.major_status))
1275 		goto out;
1276 	if (gss_write_resv(resv, PAGE_SIZE,
1277 			   &cli_handle, &ud.out_token,
1278 			   ud.major_status, ud.minor_status))
1279 		goto out;
1280 
1281 	ret = SVC_COMPLETE;
1282 out:
1283 	gssp_free_upcall_data(&ud);
1284 	return ret;
1285 }
1286 
1287 /*
1288  * Try to set the sn->use_gss_proxy variable to a new value. We only allow
1289  * it to be changed if it's currently undefined (-1). If it's any other value
1290  * then return -EBUSY unless the type wouldn't have changed anyway.
1291  */
1292 static int set_gss_proxy(struct net *net, int type)
1293 {
1294 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1295 	int ret;
1296 
1297 	WARN_ON_ONCE(type != 0 && type != 1);
1298 	ret = cmpxchg(&sn->use_gss_proxy, -1, type);
1299 	if (ret != -1 && ret != type)
1300 		return -EBUSY;
1301 	return 0;
1302 }
1303 
1304 static bool use_gss_proxy(struct net *net)
1305 {
1306 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1307 
1308 	/* If use_gss_proxy is still undefined, then try to disable it */
1309 	if (sn->use_gss_proxy == -1)
1310 		set_gss_proxy(net, 0);
1311 	return sn->use_gss_proxy;
1312 }
1313 
1314 #ifdef CONFIG_PROC_FS
1315 
1316 static ssize_t write_gssp(struct file *file, const char __user *buf,
1317 			 size_t count, loff_t *ppos)
1318 {
1319 	struct net *net = PDE_DATA(file_inode(file));
1320 	char tbuf[20];
1321 	unsigned long i;
1322 	int res;
1323 
1324 	if (*ppos || count > sizeof(tbuf)-1)
1325 		return -EINVAL;
1326 	if (copy_from_user(tbuf, buf, count))
1327 		return -EFAULT;
1328 
1329 	tbuf[count] = 0;
1330 	res = kstrtoul(tbuf, 0, &i);
1331 	if (res)
1332 		return res;
1333 	if (i != 1)
1334 		return -EINVAL;
1335 	res = set_gssp_clnt(net);
1336 	if (res)
1337 		return res;
1338 	res = set_gss_proxy(net, 1);
1339 	if (res)
1340 		return res;
1341 	return count;
1342 }
1343 
1344 static ssize_t read_gssp(struct file *file, char __user *buf,
1345 			 size_t count, loff_t *ppos)
1346 {
1347 	struct net *net = PDE_DATA(file_inode(file));
1348 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1349 	unsigned long p = *ppos;
1350 	char tbuf[10];
1351 	size_t len;
1352 
1353 	snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
1354 	len = strlen(tbuf);
1355 	if (p >= len)
1356 		return 0;
1357 	len -= p;
1358 	if (len > count)
1359 		len = count;
1360 	if (copy_to_user(buf, (void *)(tbuf+p), len))
1361 		return -EFAULT;
1362 	*ppos += len;
1363 	return len;
1364 }
1365 
1366 static const struct file_operations use_gss_proxy_ops = {
1367 	.open = nonseekable_open,
1368 	.write = write_gssp,
1369 	.read = read_gssp,
1370 };
1371 
1372 static int create_use_gss_proxy_proc_entry(struct net *net)
1373 {
1374 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1375 	struct proc_dir_entry **p = &sn->use_gssp_proc;
1376 
1377 	sn->use_gss_proxy = -1;
1378 	*p = proc_create_data("use-gss-proxy", S_IFREG|S_IRUSR|S_IWUSR,
1379 			      sn->proc_net_rpc,
1380 			      &use_gss_proxy_ops, net);
1381 	if (!*p)
1382 		return -ENOMEM;
1383 	init_gssp_clnt(sn);
1384 	return 0;
1385 }
1386 
1387 static void destroy_use_gss_proxy_proc_entry(struct net *net)
1388 {
1389 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1390 
1391 	if (sn->use_gssp_proc) {
1392 		remove_proc_entry("use-gss-proxy", sn->proc_net_rpc);
1393 		clear_gssp_clnt(sn);
1394 	}
1395 }
1396 #else /* CONFIG_PROC_FS */
1397 
1398 static int create_use_gss_proxy_proc_entry(struct net *net)
1399 {
1400 	return 0;
1401 }
1402 
1403 static void destroy_use_gss_proxy_proc_entry(struct net *net) {}
1404 
1405 #endif /* CONFIG_PROC_FS */
1406 
1407 /*
1408  * Accept an rpcsec packet.
1409  * If context establishment, punt to user space
1410  * If data exchange, verify/decrypt
1411  * If context destruction, handle here
1412  * In the context establishment and destruction case we encode
1413  * response here and return SVC_COMPLETE.
1414  */
1415 static int
1416 svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
1417 {
1418 	struct kvec	*argv = &rqstp->rq_arg.head[0];
1419 	struct kvec	*resv = &rqstp->rq_res.head[0];
1420 	u32		crlen;
1421 	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
1422 	struct rpc_gss_wire_cred *gc;
1423 	struct rsc	*rsci = NULL;
1424 	__be32		*rpcstart;
1425 	__be32		*reject_stat = resv->iov_base + resv->iov_len;
1426 	int		ret;
1427 	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1428 
1429 	dprintk("RPC:       svcauth_gss: argv->iov_len = %zd\n",
1430 			argv->iov_len);
1431 
1432 	*authp = rpc_autherr_badcred;
1433 	if (!svcdata)
1434 		svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL);
1435 	if (!svcdata)
1436 		goto auth_err;
1437 	rqstp->rq_auth_data = svcdata;
1438 	svcdata->verf_start = NULL;
1439 	svcdata->rsci = NULL;
1440 	gc = &svcdata->clcred;
1441 
1442 	/* start of rpc packet is 7 u32's back from here:
1443 	 * xid direction rpcversion prog vers proc flavour
1444 	 */
1445 	rpcstart = argv->iov_base;
1446 	rpcstart -= 7;
1447 
1448 	/* credential is:
1449 	 *   version(==1), proc(0,1,2,3), seq, service (1,2,3), handle
1450 	 * at least 5 u32s, and is preceded by length, so that makes 6.
1451 	 */
1452 
1453 	if (argv->iov_len < 5 * 4)
1454 		goto auth_err;
1455 	crlen = svc_getnl(argv);
1456 	if (svc_getnl(argv) != RPC_GSS_VERSION)
1457 		goto auth_err;
1458 	gc->gc_proc = svc_getnl(argv);
1459 	gc->gc_seq = svc_getnl(argv);
1460 	gc->gc_svc = svc_getnl(argv);
1461 	if (svc_safe_getnetobj(argv, &gc->gc_ctx))
1462 		goto auth_err;
1463 	if (crlen != round_up_to_quad(gc->gc_ctx.len) + 5 * 4)
1464 		goto auth_err;
1465 
1466 	if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0))
1467 		goto auth_err;
1468 
1469 	*authp = rpc_autherr_badverf;
1470 	switch (gc->gc_proc) {
1471 	case RPC_GSS_PROC_INIT:
1472 	case RPC_GSS_PROC_CONTINUE_INIT:
1473 		if (use_gss_proxy(SVC_NET(rqstp)))
1474 			return svcauth_gss_proxy_init(rqstp, gc, authp);
1475 		else
1476 			return svcauth_gss_legacy_init(rqstp, gc, authp);
1477 	case RPC_GSS_PROC_DATA:
1478 	case RPC_GSS_PROC_DESTROY:
1479 		/* Look up the context, and check the verifier: */
1480 		*authp = rpcsec_gsserr_credproblem;
1481 		rsci = gss_svc_searchbyctx(sn->rsc_cache, &gc->gc_ctx);
1482 		if (!rsci)
1483 			goto auth_err;
1484 		switch (gss_verify_header(rqstp, rsci, rpcstart, gc, authp)) {
1485 		case SVC_OK:
1486 			break;
1487 		case SVC_DENIED:
1488 			goto auth_err;
1489 		case SVC_DROP:
1490 			goto drop;
1491 		}
1492 		break;
1493 	default:
1494 		*authp = rpc_autherr_rejectedcred;
1495 		goto auth_err;
1496 	}
1497 
1498 	/* now act upon the command: */
1499 	switch (gc->gc_proc) {
1500 	case RPC_GSS_PROC_DESTROY:
1501 		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
1502 			goto auth_err;
1503 		/* Delete the entry from the cache_list and call cache_put */
1504 		sunrpc_cache_unhash(sn->rsc_cache, &rsci->h);
1505 		if (resv->iov_len + 4 > PAGE_SIZE)
1506 			goto drop;
1507 		svc_putnl(resv, RPC_SUCCESS);
1508 		goto complete;
1509 	case RPC_GSS_PROC_DATA:
1510 		*authp = rpcsec_gsserr_ctxproblem;
1511 		svcdata->verf_start = resv->iov_base + resv->iov_len;
1512 		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
1513 			goto auth_err;
1514 		rqstp->rq_cred = rsci->cred;
1515 		get_group_info(rsci->cred.cr_group_info);
1516 		*authp = rpc_autherr_badcred;
1517 		switch (gc->gc_svc) {
1518 		case RPC_GSS_SVC_NONE:
1519 			break;
1520 		case RPC_GSS_SVC_INTEGRITY:
1521 			/* placeholders for length and seq. number: */
1522 			svc_putnl(resv, 0);
1523 			svc_putnl(resv, 0);
1524 			if (unwrap_integ_data(rqstp, &rqstp->rq_arg,
1525 					gc->gc_seq, rsci->mechctx))
1526 				goto garbage_args;
1527 			rqstp->rq_auth_slack = RPC_MAX_AUTH_SIZE;
1528 			break;
1529 		case RPC_GSS_SVC_PRIVACY:
1530 			/* placeholders for length and seq. number: */
1531 			svc_putnl(resv, 0);
1532 			svc_putnl(resv, 0);
1533 			if (unwrap_priv_data(rqstp, &rqstp->rq_arg,
1534 					gc->gc_seq, rsci->mechctx))
1535 				goto garbage_args;
1536 			rqstp->rq_auth_slack = RPC_MAX_AUTH_SIZE * 2;
1537 			break;
1538 		default:
1539 			goto auth_err;
1540 		}
1541 		svcdata->rsci = rsci;
1542 		cache_get(&rsci->h);
1543 		rqstp->rq_cred.cr_flavor = gss_svc_to_pseudoflavor(
1544 					rsci->mechctx->mech_type,
1545 					GSS_C_QOP_DEFAULT,
1546 					gc->gc_svc);
1547 		ret = SVC_OK;
1548 		goto out;
1549 	}
1550 garbage_args:
1551 	ret = SVC_GARBAGE;
1552 	goto out;
1553 auth_err:
1554 	/* Restore write pointer to its original value: */
1555 	xdr_ressize_check(rqstp, reject_stat);
1556 	ret = SVC_DENIED;
1557 	goto out;
1558 complete:
1559 	ret = SVC_COMPLETE;
1560 	goto out;
1561 drop:
1562 	ret = SVC_CLOSE;
1563 out:
1564 	if (rsci)
1565 		cache_put(&rsci->h, sn->rsc_cache);
1566 	return ret;
1567 }
1568 
1569 static __be32 *
1570 svcauth_gss_prepare_to_wrap(struct xdr_buf *resbuf, struct gss_svc_data *gsd)
1571 {
1572 	__be32 *p;
1573 	u32 verf_len;
1574 
1575 	p = gsd->verf_start;
1576 	gsd->verf_start = NULL;
1577 
1578 	/* If the reply stat is nonzero, don't wrap: */
1579 	if (*(p-1) != rpc_success)
1580 		return NULL;
1581 	/* Skip the verifier: */
1582 	p += 1;
1583 	verf_len = ntohl(*p++);
1584 	p += XDR_QUADLEN(verf_len);
1585 	/* move accept_stat to right place: */
1586 	memcpy(p, p + 2, 4);
1587 	/* Also don't wrap if the accept stat is nonzero: */
1588 	if (*p != rpc_success) {
1589 		resbuf->head[0].iov_len -= 2 * 4;
1590 		return NULL;
1591 	}
1592 	p++;
1593 	return p;
1594 }
1595 
1596 static inline int
1597 svcauth_gss_wrap_resp_integ(struct svc_rqst *rqstp)
1598 {
1599 	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1600 	struct rpc_gss_wire_cred *gc = &gsd->clcred;
1601 	struct xdr_buf *resbuf = &rqstp->rq_res;
1602 	struct xdr_buf integ_buf;
1603 	struct xdr_netobj mic;
1604 	struct kvec *resv;
1605 	__be32 *p;
1606 	int integ_offset, integ_len;
1607 	int stat = -EINVAL;
1608 
1609 	p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
1610 	if (p == NULL)
1611 		goto out;
1612 	integ_offset = (u8 *)(p + 1) - (u8 *)resbuf->head[0].iov_base;
1613 	integ_len = resbuf->len - integ_offset;
1614 	BUG_ON(integ_len % 4);
1615 	*p++ = htonl(integ_len);
1616 	*p++ = htonl(gc->gc_seq);
1617 	if (xdr_buf_subsegment(resbuf, &integ_buf, integ_offset, integ_len)) {
1618 		WARN_ON_ONCE(1);
1619 		goto out_err;
1620 	}
1621 	if (resbuf->tail[0].iov_base == NULL) {
1622 		if (resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1623 			goto out_err;
1624 		resbuf->tail[0].iov_base = resbuf->head[0].iov_base
1625 						+ resbuf->head[0].iov_len;
1626 		resbuf->tail[0].iov_len = 0;
1627 	}
1628 	resv = &resbuf->tail[0];
1629 	mic.data = (u8 *)resv->iov_base + resv->iov_len + 4;
1630 	if (gss_get_mic(gsd->rsci->mechctx, &integ_buf, &mic))
1631 		goto out_err;
1632 	svc_putnl(resv, mic.len);
1633 	memset(mic.data + mic.len, 0,
1634 			round_up_to_quad(mic.len) - mic.len);
1635 	resv->iov_len += XDR_QUADLEN(mic.len) << 2;
1636 	/* not strictly required: */
1637 	resbuf->len += XDR_QUADLEN(mic.len) << 2;
1638 	BUG_ON(resv->iov_len > PAGE_SIZE);
1639 out:
1640 	stat = 0;
1641 out_err:
1642 	return stat;
1643 }
1644 
1645 static inline int
1646 svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp)
1647 {
1648 	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1649 	struct rpc_gss_wire_cred *gc = &gsd->clcred;
1650 	struct xdr_buf *resbuf = &rqstp->rq_res;
1651 	struct page **inpages = NULL;
1652 	__be32 *p, *len;
1653 	int offset;
1654 	int pad;
1655 
1656 	p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
1657 	if (p == NULL)
1658 		return 0;
1659 	len = p++;
1660 	offset = (u8 *)p - (u8 *)resbuf->head[0].iov_base;
1661 	*p++ = htonl(gc->gc_seq);
1662 	inpages = resbuf->pages;
1663 	/* XXX: Would be better to write some xdr helper functions for
1664 	 * nfs{2,3,4}xdr.c that place the data right, instead of copying: */
1665 
1666 	/*
1667 	 * If there is currently tail data, make sure there is
1668 	 * room for the head, tail, and 2 * RPC_MAX_AUTH_SIZE in
1669 	 * the page, and move the current tail data such that
1670 	 * there is RPC_MAX_AUTH_SIZE slack space available in
1671 	 * both the head and tail.
1672 	 */
1673 	if (resbuf->tail[0].iov_base) {
1674 		BUG_ON(resbuf->tail[0].iov_base >= resbuf->head[0].iov_base
1675 							+ PAGE_SIZE);
1676 		BUG_ON(resbuf->tail[0].iov_base < resbuf->head[0].iov_base);
1677 		if (resbuf->tail[0].iov_len + resbuf->head[0].iov_len
1678 				+ 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1679 			return -ENOMEM;
1680 		memmove(resbuf->tail[0].iov_base + RPC_MAX_AUTH_SIZE,
1681 			resbuf->tail[0].iov_base,
1682 			resbuf->tail[0].iov_len);
1683 		resbuf->tail[0].iov_base += RPC_MAX_AUTH_SIZE;
1684 	}
1685 	/*
1686 	 * If there is no current tail data, make sure there is
1687 	 * room for the head data, and 2 * RPC_MAX_AUTH_SIZE in the
1688 	 * allotted page, and set up tail information such that there
1689 	 * is RPC_MAX_AUTH_SIZE slack space available in both the
1690 	 * head and tail.
1691 	 */
1692 	if (resbuf->tail[0].iov_base == NULL) {
1693 		if (resbuf->head[0].iov_len + 2*RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1694 			return -ENOMEM;
1695 		resbuf->tail[0].iov_base = resbuf->head[0].iov_base
1696 			+ resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE;
1697 		resbuf->tail[0].iov_len = 0;
1698 	}
1699 	if (gss_wrap(gsd->rsci->mechctx, offset, resbuf, inpages))
1700 		return -ENOMEM;
1701 	*len = htonl(resbuf->len - offset);
1702 	pad = 3 - ((resbuf->len - offset - 1)&3);
1703 	p = (__be32 *)(resbuf->tail[0].iov_base + resbuf->tail[0].iov_len);
1704 	memset(p, 0, pad);
1705 	resbuf->tail[0].iov_len += pad;
1706 	resbuf->len += pad;
1707 	return 0;
1708 }
1709 
1710 static int
1711 svcauth_gss_release(struct svc_rqst *rqstp)
1712 {
1713 	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1714 	struct rpc_gss_wire_cred *gc = &gsd->clcred;
1715 	struct xdr_buf *resbuf = &rqstp->rq_res;
1716 	int stat = -EINVAL;
1717 	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1718 
1719 	if (gc->gc_proc != RPC_GSS_PROC_DATA)
1720 		goto out;
1721 	/* Release can be called twice, but we only wrap once. */
1722 	if (gsd->verf_start == NULL)
1723 		goto out;
1724 	/* normally not set till svc_send, but we need it here: */
1725 	/* XXX: what for?  Do we mess it up the moment we call svc_putu32
1726 	 * or whatever? */
1727 	resbuf->len = total_buf_len(resbuf);
1728 	switch (gc->gc_svc) {
1729 	case RPC_GSS_SVC_NONE:
1730 		break;
1731 	case RPC_GSS_SVC_INTEGRITY:
1732 		stat = svcauth_gss_wrap_resp_integ(rqstp);
1733 		if (stat)
1734 			goto out_err;
1735 		break;
1736 	case RPC_GSS_SVC_PRIVACY:
1737 		stat = svcauth_gss_wrap_resp_priv(rqstp);
1738 		if (stat)
1739 			goto out_err;
1740 		break;
1741 	/*
1742 	 * For any other gc_svc value, svcauth_gss_accept() already set
1743 	 * the auth_error appropriately; just fall through:
1744 	 */
1745 	}
1746 
1747 out:
1748 	stat = 0;
1749 out_err:
1750 	if (rqstp->rq_client)
1751 		auth_domain_put(rqstp->rq_client);
1752 	rqstp->rq_client = NULL;
1753 	if (rqstp->rq_gssclient)
1754 		auth_domain_put(rqstp->rq_gssclient);
1755 	rqstp->rq_gssclient = NULL;
1756 	if (rqstp->rq_cred.cr_group_info)
1757 		put_group_info(rqstp->rq_cred.cr_group_info);
1758 	rqstp->rq_cred.cr_group_info = NULL;
1759 	if (gsd->rsci)
1760 		cache_put(&gsd->rsci->h, sn->rsc_cache);
1761 	gsd->rsci = NULL;
1762 
1763 	return stat;
1764 }
1765 
1766 static void
1767 svcauth_gss_domain_release(struct auth_domain *dom)
1768 {
1769 	struct gss_domain *gd = container_of(dom, struct gss_domain, h);
1770 
1771 	kfree(dom->name);
1772 	kfree(gd);
1773 }
1774 
1775 static struct auth_ops svcauthops_gss = {
1776 	.name		= "rpcsec_gss",
1777 	.owner		= THIS_MODULE,
1778 	.flavour	= RPC_AUTH_GSS,
1779 	.accept		= svcauth_gss_accept,
1780 	.release	= svcauth_gss_release,
1781 	.domain_release = svcauth_gss_domain_release,
1782 	.set_client	= svcauth_gss_set_client,
1783 };
1784 
1785 static int rsi_cache_create_net(struct net *net)
1786 {
1787 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1788 	struct cache_detail *cd;
1789 	int err;
1790 
1791 	cd = cache_create_net(&rsi_cache_template, net);
1792 	if (IS_ERR(cd))
1793 		return PTR_ERR(cd);
1794 	err = cache_register_net(cd, net);
1795 	if (err) {
1796 		cache_destroy_net(cd, net);
1797 		return err;
1798 	}
1799 	sn->rsi_cache = cd;
1800 	return 0;
1801 }
1802 
1803 static void rsi_cache_destroy_net(struct net *net)
1804 {
1805 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1806 	struct cache_detail *cd = sn->rsi_cache;
1807 
1808 	sn->rsi_cache = NULL;
1809 	cache_purge(cd);
1810 	cache_unregister_net(cd, net);
1811 	cache_destroy_net(cd, net);
1812 }
1813 
1814 static int rsc_cache_create_net(struct net *net)
1815 {
1816 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1817 	struct cache_detail *cd;
1818 	int err;
1819 
1820 	cd = cache_create_net(&rsc_cache_template, net);
1821 	if (IS_ERR(cd))
1822 		return PTR_ERR(cd);
1823 	err = cache_register_net(cd, net);
1824 	if (err) {
1825 		cache_destroy_net(cd, net);
1826 		return err;
1827 	}
1828 	sn->rsc_cache = cd;
1829 	return 0;
1830 }
1831 
1832 static void rsc_cache_destroy_net(struct net *net)
1833 {
1834 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1835 	struct cache_detail *cd = sn->rsc_cache;
1836 
1837 	sn->rsc_cache = NULL;
1838 	cache_purge(cd);
1839 	cache_unregister_net(cd, net);
1840 	cache_destroy_net(cd, net);
1841 }
1842 
1843 int
1844 gss_svc_init_net(struct net *net)
1845 {
1846 	int rv;
1847 
1848 	rv = rsc_cache_create_net(net);
1849 	if (rv)
1850 		return rv;
1851 	rv = rsi_cache_create_net(net);
1852 	if (rv)
1853 		goto out1;
1854 	rv = create_use_gss_proxy_proc_entry(net);
1855 	if (rv)
1856 		goto out2;
1857 	return 0;
1858 out2:
1859 	destroy_use_gss_proxy_proc_entry(net);
1860 out1:
1861 	rsc_cache_destroy_net(net);
1862 	return rv;
1863 }
1864 
1865 void
1866 gss_svc_shutdown_net(struct net *net)
1867 {
1868 	destroy_use_gss_proxy_proc_entry(net);
1869 	rsi_cache_destroy_net(net);
1870 	rsc_cache_destroy_net(net);
1871 }
1872 
1873 int
1874 gss_svc_init(void)
1875 {
1876 	return svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss);
1877 }
1878 
1879 void
1880 gss_svc_shutdown(void)
1881 {
1882 	svc_auth_unregister(RPC_AUTH_GSS);
1883 }
1884