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 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 			GROUP_AT(rsci.cred.cr_group_info, i) = kgid;
483 		}
484 
485 		/* mech name */
486 		len = qword_get(&mesg, buf, mlen);
487 		if (len < 0)
488 			goto out;
489 		gm = rsci.cred.cr_gss_mech = gss_mech_get_by_name(buf);
490 		status = -EOPNOTSUPP;
491 		if (!gm)
492 			goto out;
493 
494 		status = -EINVAL;
495 		/* mech-specific data: */
496 		len = qword_get(&mesg, buf, mlen);
497 		if (len < 0)
498 			goto out;
499 		status = gss_import_sec_context(buf, len, gm, &rsci.mechctx,
500 						NULL, GFP_KERNEL);
501 		if (status)
502 			goto out;
503 
504 		/* get client name */
505 		len = qword_get(&mesg, buf, mlen);
506 		if (len > 0) {
507 			rsci.cred.cr_principal = kstrdup(buf, GFP_KERNEL);
508 			if (!rsci.cred.cr_principal) {
509 				status = -ENOMEM;
510 				goto out;
511 			}
512 		}
513 
514 	}
515 	rsci.h.expiry_time = expiry;
516 	rscp = rsc_update(cd, &rsci, rscp);
517 	status = 0;
518 out:
519 	rsc_free(&rsci);
520 	if (rscp)
521 		cache_put(&rscp->h, cd);
522 	else
523 		status = -ENOMEM;
524 	return status;
525 }
526 
527 static struct cache_detail rsc_cache_template = {
528 	.owner		= THIS_MODULE,
529 	.hash_size	= RSC_HASHMAX,
530 	.name		= "auth.rpcsec.context",
531 	.cache_put	= rsc_put,
532 	.cache_parse	= rsc_parse,
533 	.match		= rsc_match,
534 	.init		= rsc_init,
535 	.update		= update_rsc,
536 	.alloc		= rsc_alloc,
537 };
538 
539 static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item)
540 {
541 	struct cache_head *ch;
542 	int hash = rsc_hash(item);
543 
544 	ch = sunrpc_cache_lookup(cd, &item->h, hash);
545 	if (ch)
546 		return container_of(ch, struct rsc, h);
547 	else
548 		return NULL;
549 }
550 
551 static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old)
552 {
553 	struct cache_head *ch;
554 	int hash = rsc_hash(new);
555 
556 	ch = sunrpc_cache_update(cd, &new->h,
557 				 &old->h, hash);
558 	if (ch)
559 		return container_of(ch, struct rsc, h);
560 	else
561 		return NULL;
562 }
563 
564 
565 static struct rsc *
566 gss_svc_searchbyctx(struct cache_detail *cd, struct xdr_netobj *handle)
567 {
568 	struct rsc rsci;
569 	struct rsc *found;
570 
571 	memset(&rsci, 0, sizeof(rsci));
572 	rsci.handle.data = handle->data;
573 	rsci.handle.len = handle->len;
574 	found = rsc_lookup(cd, &rsci);
575 	if (!found)
576 		return NULL;
577 	if (cache_check(cd, &found->h, NULL))
578 		return NULL;
579 	return found;
580 }
581 
582 /* Implements sequence number algorithm as specified in RFC 2203. */
583 static int
584 gss_check_seq_num(struct rsc *rsci, int seq_num)
585 {
586 	struct gss_svc_seq_data *sd = &rsci->seqdata;
587 
588 	spin_lock(&sd->sd_lock);
589 	if (seq_num > sd->sd_max) {
590 		if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
591 			memset(sd->sd_win,0,sizeof(sd->sd_win));
592 			sd->sd_max = seq_num;
593 		} else while (sd->sd_max < seq_num) {
594 			sd->sd_max++;
595 			__clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
596 		}
597 		__set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
598 		goto ok;
599 	} else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) {
600 		goto drop;
601 	}
602 	/* sd_max - GSS_SEQ_WIN < seq_num <= sd_max */
603 	if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
604 		goto drop;
605 ok:
606 	spin_unlock(&sd->sd_lock);
607 	return 1;
608 drop:
609 	spin_unlock(&sd->sd_lock);
610 	return 0;
611 }
612 
613 static inline u32 round_up_to_quad(u32 i)
614 {
615 	return (i + 3 ) & ~3;
616 }
617 
618 static inline int
619 svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o)
620 {
621 	int l;
622 
623 	if (argv->iov_len < 4)
624 		return -1;
625 	o->len = svc_getnl(argv);
626 	l = round_up_to_quad(o->len);
627 	if (argv->iov_len < l)
628 		return -1;
629 	o->data = argv->iov_base;
630 	argv->iov_base += l;
631 	argv->iov_len -= l;
632 	return 0;
633 }
634 
635 static inline int
636 svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
637 {
638 	u8 *p;
639 
640 	if (resv->iov_len + 4 > PAGE_SIZE)
641 		return -1;
642 	svc_putnl(resv, o->len);
643 	p = resv->iov_base + resv->iov_len;
644 	resv->iov_len += round_up_to_quad(o->len);
645 	if (resv->iov_len > PAGE_SIZE)
646 		return -1;
647 	memcpy(p, o->data, o->len);
648 	memset(p + o->len, 0, round_up_to_quad(o->len) - o->len);
649 	return 0;
650 }
651 
652 /*
653  * Verify the checksum on the header and return SVC_OK on success.
654  * Otherwise, return SVC_DROP (in the case of a bad sequence number)
655  * or return SVC_DENIED and indicate error in authp.
656  */
657 static int
658 gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
659 		  __be32 *rpcstart, struct rpc_gss_wire_cred *gc, __be32 *authp)
660 {
661 	struct gss_ctx		*ctx_id = rsci->mechctx;
662 	struct xdr_buf		rpchdr;
663 	struct xdr_netobj	checksum;
664 	u32			flavor = 0;
665 	struct kvec		*argv = &rqstp->rq_arg.head[0];
666 	struct kvec		iov;
667 
668 	/* data to compute the checksum over: */
669 	iov.iov_base = rpcstart;
670 	iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart;
671 	xdr_buf_from_iov(&iov, &rpchdr);
672 
673 	*authp = rpc_autherr_badverf;
674 	if (argv->iov_len < 4)
675 		return SVC_DENIED;
676 	flavor = svc_getnl(argv);
677 	if (flavor != RPC_AUTH_GSS)
678 		return SVC_DENIED;
679 	if (svc_safe_getnetobj(argv, &checksum))
680 		return SVC_DENIED;
681 
682 	if (rqstp->rq_deferred) /* skip verification of revisited request */
683 		return SVC_OK;
684 	if (gss_verify_mic(ctx_id, &rpchdr, &checksum) != GSS_S_COMPLETE) {
685 		*authp = rpcsec_gsserr_credproblem;
686 		return SVC_DENIED;
687 	}
688 
689 	if (gc->gc_seq > MAXSEQ) {
690 		dprintk("RPC:       svcauth_gss: discarding request with "
691 				"large sequence number %d\n", gc->gc_seq);
692 		*authp = rpcsec_gsserr_ctxproblem;
693 		return SVC_DENIED;
694 	}
695 	if (!gss_check_seq_num(rsci, gc->gc_seq)) {
696 		dprintk("RPC:       svcauth_gss: discarding request with "
697 				"old sequence number %d\n", gc->gc_seq);
698 		return SVC_DROP;
699 	}
700 	return SVC_OK;
701 }
702 
703 static int
704 gss_write_null_verf(struct svc_rqst *rqstp)
705 {
706 	__be32     *p;
707 
708 	svc_putnl(rqstp->rq_res.head, RPC_AUTH_NULL);
709 	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
710 	/* don't really need to check if head->iov_len > PAGE_SIZE ... */
711 	*p++ = 0;
712 	if (!xdr_ressize_check(rqstp, p))
713 		return -1;
714 	return 0;
715 }
716 
717 static int
718 gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
719 {
720 	__be32			xdr_seq;
721 	u32			maj_stat;
722 	struct xdr_buf		verf_data;
723 	struct xdr_netobj	mic;
724 	__be32			*p;
725 	struct kvec		iov;
726 
727 	svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
728 	xdr_seq = htonl(seq);
729 
730 	iov.iov_base = &xdr_seq;
731 	iov.iov_len = sizeof(xdr_seq);
732 	xdr_buf_from_iov(&iov, &verf_data);
733 	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
734 	mic.data = (u8 *)(p + 1);
735 	maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
736 	if (maj_stat != GSS_S_COMPLETE)
737 		return -1;
738 	*p++ = htonl(mic.len);
739 	memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
740 	p += XDR_QUADLEN(mic.len);
741 	if (!xdr_ressize_check(rqstp, p))
742 		return -1;
743 	return 0;
744 }
745 
746 struct gss_domain {
747 	struct auth_domain	h;
748 	u32			pseudoflavor;
749 };
750 
751 static struct auth_domain *
752 find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
753 {
754 	char *name;
755 
756 	name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
757 	if (!name)
758 		return NULL;
759 	return auth_domain_find(name);
760 }
761 
762 static struct auth_ops svcauthops_gss;
763 
764 u32 svcauth_gss_flavor(struct auth_domain *dom)
765 {
766 	struct gss_domain *gd = container_of(dom, struct gss_domain, h);
767 
768 	return gd->pseudoflavor;
769 }
770 
771 EXPORT_SYMBOL_GPL(svcauth_gss_flavor);
772 
773 int
774 svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
775 {
776 	struct gss_domain	*new;
777 	struct auth_domain	*test;
778 	int			stat = -ENOMEM;
779 
780 	new = kmalloc(sizeof(*new), GFP_KERNEL);
781 	if (!new)
782 		goto out;
783 	kref_init(&new->h.ref);
784 	new->h.name = kstrdup(name, GFP_KERNEL);
785 	if (!new->h.name)
786 		goto out_free_dom;
787 	new->h.flavour = &svcauthops_gss;
788 	new->pseudoflavor = pseudoflavor;
789 
790 	stat = 0;
791 	test = auth_domain_lookup(name, &new->h);
792 	if (test != &new->h) { /* Duplicate registration */
793 		auth_domain_put(test);
794 		kfree(new->h.name);
795 		goto out_free_dom;
796 	}
797 	return 0;
798 
799 out_free_dom:
800 	kfree(new);
801 out:
802 	return stat;
803 }
804 
805 EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor);
806 
807 static inline int
808 read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
809 {
810 	__be32  raw;
811 	int     status;
812 
813 	status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
814 	if (status)
815 		return status;
816 	*obj = ntohl(raw);
817 	return 0;
818 }
819 
820 /* It would be nice if this bit of code could be shared with the client.
821  * Obstacles:
822  *	The client shouldn't malloc(), would have to pass in own memory.
823  *	The server uses base of head iovec as read pointer, while the
824  *	client uses separate pointer. */
825 static int
826 unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
827 {
828 	int stat = -EINVAL;
829 	u32 integ_len, maj_stat;
830 	struct xdr_netobj mic;
831 	struct xdr_buf integ_buf;
832 
833 	/* Did we already verify the signature on the original pass through? */
834 	if (rqstp->rq_deferred)
835 		return 0;
836 
837 	integ_len = svc_getnl(&buf->head[0]);
838 	if (integ_len & 3)
839 		return stat;
840 	if (integ_len > buf->len)
841 		return stat;
842 	if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len))
843 		BUG();
844 	/* copy out mic... */
845 	if (read_u32_from_xdr_buf(buf, integ_len, &mic.len))
846 		BUG();
847 	if (mic.len > RPC_MAX_AUTH_SIZE)
848 		return stat;
849 	mic.data = kmalloc(mic.len, GFP_KERNEL);
850 	if (!mic.data)
851 		return stat;
852 	if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len))
853 		goto out;
854 	maj_stat = gss_verify_mic(ctx, &integ_buf, &mic);
855 	if (maj_stat != GSS_S_COMPLETE)
856 		goto out;
857 	if (svc_getnl(&buf->head[0]) != seq)
858 		goto out;
859 	/* trim off the mic and padding at the end before returning */
860 	xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4);
861 	stat = 0;
862 out:
863 	kfree(mic.data);
864 	return stat;
865 }
866 
867 static inline int
868 total_buf_len(struct xdr_buf *buf)
869 {
870 	return buf->head[0].iov_len + buf->page_len + buf->tail[0].iov_len;
871 }
872 
873 static void
874 fix_priv_head(struct xdr_buf *buf, int pad)
875 {
876 	if (buf->page_len == 0) {
877 		/* We need to adjust head and buf->len in tandem in this
878 		 * case to make svc_defer() work--it finds the original
879 		 * buffer start using buf->len - buf->head[0].iov_len. */
880 		buf->head[0].iov_len -= pad;
881 	}
882 }
883 
884 static int
885 unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
886 {
887 	u32 priv_len, maj_stat;
888 	int pad, saved_len, remaining_len, offset;
889 
890 	clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
891 
892 	priv_len = svc_getnl(&buf->head[0]);
893 	if (rqstp->rq_deferred) {
894 		/* Already decrypted last time through! The sequence number
895 		 * check at out_seq is unnecessary but harmless: */
896 		goto out_seq;
897 	}
898 	/* buf->len is the number of bytes from the original start of the
899 	 * request to the end, where head[0].iov_len is just the bytes
900 	 * not yet read from the head, so these two values are different: */
901 	remaining_len = total_buf_len(buf);
902 	if (priv_len > remaining_len)
903 		return -EINVAL;
904 	pad = remaining_len - priv_len;
905 	buf->len -= pad;
906 	fix_priv_head(buf, pad);
907 
908 	/* Maybe it would be better to give gss_unwrap a length parameter: */
909 	saved_len = buf->len;
910 	buf->len = priv_len;
911 	maj_stat = gss_unwrap(ctx, 0, buf);
912 	pad = priv_len - buf->len;
913 	buf->len = saved_len;
914 	buf->len -= pad;
915 	/* The upper layers assume the buffer is aligned on 4-byte boundaries.
916 	 * In the krb5p case, at least, the data ends up offset, so we need to
917 	 * move it around. */
918 	/* XXX: This is very inefficient.  It would be better to either do
919 	 * this while we encrypt, or maybe in the receive code, if we can peak
920 	 * ahead and work out the service and mechanism there. */
921 	offset = buf->head[0].iov_len % 4;
922 	if (offset) {
923 		buf->buflen = RPCSVC_MAXPAYLOAD;
924 		xdr_shift_buf(buf, offset);
925 		fix_priv_head(buf, pad);
926 	}
927 	if (maj_stat != GSS_S_COMPLETE)
928 		return -EINVAL;
929 out_seq:
930 	if (svc_getnl(&buf->head[0]) != seq)
931 		return -EINVAL;
932 	return 0;
933 }
934 
935 struct gss_svc_data {
936 	/* decoded gss client cred: */
937 	struct rpc_gss_wire_cred	clcred;
938 	/* save a pointer to the beginning of the encoded verifier,
939 	 * for use in encryption/checksumming in svcauth_gss_release: */
940 	__be32				*verf_start;
941 	struct rsc			*rsci;
942 };
943 
944 static int
945 svcauth_gss_set_client(struct svc_rqst *rqstp)
946 {
947 	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
948 	struct rsc *rsci = svcdata->rsci;
949 	struct rpc_gss_wire_cred *gc = &svcdata->clcred;
950 	int stat;
951 
952 	/*
953 	 * A gss export can be specified either by:
954 	 * 	export	*(sec=krb5,rw)
955 	 * or by
956 	 * 	export gss/krb5(rw)
957 	 * The latter is deprecated; but for backwards compatibility reasons
958 	 * the nfsd code will still fall back on trying it if the former
959 	 * doesn't work; so we try to make both available to nfsd, below.
960 	 */
961 	rqstp->rq_gssclient = find_gss_auth_domain(rsci->mechctx, gc->gc_svc);
962 	if (rqstp->rq_gssclient == NULL)
963 		return SVC_DENIED;
964 	stat = svcauth_unix_set_client(rqstp);
965 	if (stat == SVC_DROP || stat == SVC_CLOSE)
966 		return stat;
967 	return SVC_OK;
968 }
969 
970 static inline int
971 gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,
972 		struct xdr_netobj *out_handle, int *major_status)
973 {
974 	struct rsc *rsci;
975 	int        rc;
976 
977 	if (*major_status != GSS_S_COMPLETE)
978 		return gss_write_null_verf(rqstp);
979 	rsci = gss_svc_searchbyctx(cd, out_handle);
980 	if (rsci == NULL) {
981 		*major_status = GSS_S_NO_CONTEXT;
982 		return gss_write_null_verf(rqstp);
983 	}
984 	rc = gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN);
985 	cache_put(&rsci->h, cd);
986 	return rc;
987 }
988 
989 static inline int
990 gss_read_common_verf(struct rpc_gss_wire_cred *gc,
991 		     struct kvec *argv, __be32 *authp,
992 		     struct xdr_netobj *in_handle)
993 {
994 	/* Read the verifier; should be NULL: */
995 	*authp = rpc_autherr_badverf;
996 	if (argv->iov_len < 2 * 4)
997 		return SVC_DENIED;
998 	if (svc_getnl(argv) != RPC_AUTH_NULL)
999 		return SVC_DENIED;
1000 	if (svc_getnl(argv) != 0)
1001 		return SVC_DENIED;
1002 	/* Martial context handle and token for upcall: */
1003 	*authp = rpc_autherr_badcred;
1004 	if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
1005 		return SVC_DENIED;
1006 	if (dup_netobj(in_handle, &gc->gc_ctx))
1007 		return SVC_CLOSE;
1008 	*authp = rpc_autherr_badverf;
1009 
1010 	return 0;
1011 }
1012 
1013 static inline int
1014 gss_read_verf(struct rpc_gss_wire_cred *gc,
1015 	      struct kvec *argv, __be32 *authp,
1016 	      struct xdr_netobj *in_handle,
1017 	      struct xdr_netobj *in_token)
1018 {
1019 	struct xdr_netobj tmpobj;
1020 	int res;
1021 
1022 	res = gss_read_common_verf(gc, argv, authp, in_handle);
1023 	if (res)
1024 		return res;
1025 
1026 	if (svc_safe_getnetobj(argv, &tmpobj)) {
1027 		kfree(in_handle->data);
1028 		return SVC_DENIED;
1029 	}
1030 	if (dup_netobj(in_token, &tmpobj)) {
1031 		kfree(in_handle->data);
1032 		return SVC_CLOSE;
1033 	}
1034 
1035 	return 0;
1036 }
1037 
1038 /* Ok this is really heavily depending on a set of semantics in
1039  * how rqstp is set up by svc_recv and pages laid down by the
1040  * server when reading a request. We are basically guaranteed that
1041  * the token lays all down linearly across a set of pages, starting
1042  * at iov_base in rq_arg.head[0] which happens to be the first of a
1043  * set of pages stored in rq_pages[].
1044  * rq_arg.head[0].iov_base will provide us the page_base to pass
1045  * to the upcall.
1046  */
1047 static inline int
1048 gss_read_proxy_verf(struct svc_rqst *rqstp,
1049 		    struct rpc_gss_wire_cred *gc, __be32 *authp,
1050 		    struct xdr_netobj *in_handle,
1051 		    struct gssp_in_token *in_token)
1052 {
1053 	struct kvec *argv = &rqstp->rq_arg.head[0];
1054 	u32 inlen;
1055 	int res;
1056 
1057 	res = gss_read_common_verf(gc, argv, authp, in_handle);
1058 	if (res)
1059 		return res;
1060 
1061 	inlen = svc_getnl(argv);
1062 	if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
1063 		return SVC_DENIED;
1064 
1065 	in_token->pages = rqstp->rq_pages;
1066 	in_token->page_base = (ulong)argv->iov_base & ~PAGE_MASK;
1067 	in_token->page_len = inlen;
1068 
1069 	return 0;
1070 }
1071 
1072 static inline int
1073 gss_write_resv(struct kvec *resv, size_t size_limit,
1074 	       struct xdr_netobj *out_handle, struct xdr_netobj *out_token,
1075 	       int major_status, int minor_status)
1076 {
1077 	if (resv->iov_len + 4 > size_limit)
1078 		return -1;
1079 	svc_putnl(resv, RPC_SUCCESS);
1080 	if (svc_safe_putnetobj(resv, out_handle))
1081 		return -1;
1082 	if (resv->iov_len + 3 * 4 > size_limit)
1083 		return -1;
1084 	svc_putnl(resv, major_status);
1085 	svc_putnl(resv, minor_status);
1086 	svc_putnl(resv, GSS_SEQ_WIN);
1087 	if (svc_safe_putnetobj(resv, out_token))
1088 		return -1;
1089 	return 0;
1090 }
1091 
1092 /*
1093  * Having read the cred already and found we're in the context
1094  * initiation case, read the verifier and initiate (or check the results
1095  * of) upcalls to userspace for help with context initiation.  If
1096  * the upcall results are available, write the verifier and result.
1097  * Otherwise, drop the request pending an answer to the upcall.
1098  */
1099 static int svcauth_gss_legacy_init(struct svc_rqst *rqstp,
1100 			struct rpc_gss_wire_cred *gc, __be32 *authp)
1101 {
1102 	struct kvec *argv = &rqstp->rq_arg.head[0];
1103 	struct kvec *resv = &rqstp->rq_res.head[0];
1104 	struct rsi *rsip, rsikey;
1105 	int ret;
1106 	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1107 
1108 	memset(&rsikey, 0, sizeof(rsikey));
1109 	ret = gss_read_verf(gc, argv, authp,
1110 			    &rsikey.in_handle, &rsikey.in_token);
1111 	if (ret)
1112 		return ret;
1113 
1114 	/* Perform upcall, or find upcall result: */
1115 	rsip = rsi_lookup(sn->rsi_cache, &rsikey);
1116 	rsi_free(&rsikey);
1117 	if (!rsip)
1118 		return SVC_CLOSE;
1119 	if (cache_check(sn->rsi_cache, &rsip->h, &rqstp->rq_chandle) < 0)
1120 		/* No upcall result: */
1121 		return SVC_CLOSE;
1122 
1123 	ret = SVC_CLOSE;
1124 	/* Got an answer to the upcall; use it: */
1125 	if (gss_write_init_verf(sn->rsc_cache, rqstp,
1126 				&rsip->out_handle, &rsip->major_status))
1127 		goto out;
1128 	if (gss_write_resv(resv, PAGE_SIZE,
1129 			   &rsip->out_handle, &rsip->out_token,
1130 			   rsip->major_status, rsip->minor_status))
1131 		goto out;
1132 
1133 	ret = SVC_COMPLETE;
1134 out:
1135 	cache_put(&rsip->h, sn->rsi_cache);
1136 	return ret;
1137 }
1138 
1139 static int gss_proxy_save_rsc(struct cache_detail *cd,
1140 				struct gssp_upcall_data *ud,
1141 				uint64_t *handle)
1142 {
1143 	struct rsc rsci, *rscp = NULL;
1144 	static atomic64_t ctxhctr;
1145 	long long ctxh;
1146 	struct gss_api_mech *gm = NULL;
1147 	time_t expiry;
1148 	int status = -EINVAL;
1149 
1150 	memset(&rsci, 0, sizeof(rsci));
1151 	/* context handle */
1152 	status = -ENOMEM;
1153 	/* the handle needs to be just a unique id,
1154 	 * use a static counter */
1155 	ctxh = atomic64_inc_return(&ctxhctr);
1156 
1157 	/* make a copy for the caller */
1158 	*handle = ctxh;
1159 
1160 	/* make a copy for the rsc cache */
1161 	if (dup_to_netobj(&rsci.handle, (char *)handle, sizeof(uint64_t)))
1162 		goto out;
1163 	rscp = rsc_lookup(cd, &rsci);
1164 	if (!rscp)
1165 		goto out;
1166 
1167 	/* creds */
1168 	if (!ud->found_creds) {
1169 		/* userspace seem buggy, we should always get at least a
1170 		 * mapping to nobody */
1171 		dprintk("RPC:       No creds found!\n");
1172 		goto out;
1173 	} else {
1174 
1175 		/* steal creds */
1176 		rsci.cred = ud->creds;
1177 		memset(&ud->creds, 0, sizeof(struct svc_cred));
1178 
1179 		status = -EOPNOTSUPP;
1180 		/* get mech handle from OID */
1181 		gm = gss_mech_get_by_OID(&ud->mech_oid);
1182 		if (!gm)
1183 			goto out;
1184 		rsci.cred.cr_gss_mech = gm;
1185 
1186 		status = -EINVAL;
1187 		/* mech-specific data: */
1188 		status = gss_import_sec_context(ud->out_handle.data,
1189 						ud->out_handle.len,
1190 						gm, &rsci.mechctx,
1191 						&expiry, GFP_KERNEL);
1192 		if (status)
1193 			goto out;
1194 	}
1195 
1196 	rsci.h.expiry_time = expiry;
1197 	rscp = rsc_update(cd, &rsci, rscp);
1198 	status = 0;
1199 out:
1200 	rsc_free(&rsci);
1201 	if (rscp)
1202 		cache_put(&rscp->h, cd);
1203 	else
1204 		status = -ENOMEM;
1205 	return status;
1206 }
1207 
1208 static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
1209 			struct rpc_gss_wire_cred *gc, __be32 *authp)
1210 {
1211 	struct kvec *resv = &rqstp->rq_res.head[0];
1212 	struct xdr_netobj cli_handle;
1213 	struct gssp_upcall_data ud;
1214 	uint64_t handle;
1215 	int status;
1216 	int ret;
1217 	struct net *net = rqstp->rq_xprt->xpt_net;
1218 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1219 
1220 	memset(&ud, 0, sizeof(ud));
1221 	ret = gss_read_proxy_verf(rqstp, gc, authp,
1222 				  &ud.in_handle, &ud.in_token);
1223 	if (ret)
1224 		return ret;
1225 
1226 	ret = SVC_CLOSE;
1227 
1228 	/* Perform synchronous upcall to gss-proxy */
1229 	status = gssp_accept_sec_context_upcall(net, &ud);
1230 	if (status)
1231 		goto out;
1232 
1233 	dprintk("RPC:       svcauth_gss: gss major status = %d\n",
1234 			ud.major_status);
1235 
1236 	switch (ud.major_status) {
1237 	case GSS_S_CONTINUE_NEEDED:
1238 		cli_handle = ud.out_handle;
1239 		break;
1240 	case GSS_S_COMPLETE:
1241 		status = gss_proxy_save_rsc(sn->rsc_cache, &ud, &handle);
1242 		if (status)
1243 			goto out;
1244 		cli_handle.data = (u8 *)&handle;
1245 		cli_handle.len = sizeof(handle);
1246 		break;
1247 	default:
1248 		ret = SVC_CLOSE;
1249 		goto out;
1250 	}
1251 
1252 	/* Got an answer to the upcall; use it: */
1253 	if (gss_write_init_verf(sn->rsc_cache, rqstp,
1254 				&cli_handle, &ud.major_status))
1255 		goto out;
1256 	if (gss_write_resv(resv, PAGE_SIZE,
1257 			   &cli_handle, &ud.out_token,
1258 			   ud.major_status, ud.minor_status))
1259 		goto out;
1260 
1261 	ret = SVC_COMPLETE;
1262 out:
1263 	gssp_free_upcall_data(&ud);
1264 	return ret;
1265 }
1266 
1267 /*
1268  * Try to set the sn->use_gss_proxy variable to a new value. We only allow
1269  * it to be changed if it's currently undefined (-1). If it's any other value
1270  * then return -EBUSY unless the type wouldn't have changed anyway.
1271  */
1272 static int set_gss_proxy(struct net *net, int type)
1273 {
1274 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1275 	int ret;
1276 
1277 	WARN_ON_ONCE(type != 0 && type != 1);
1278 	ret = cmpxchg(&sn->use_gss_proxy, -1, type);
1279 	if (ret != -1 && ret != type)
1280 		return -EBUSY;
1281 	return 0;
1282 }
1283 
1284 static bool use_gss_proxy(struct net *net)
1285 {
1286 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1287 
1288 	/* If use_gss_proxy is still undefined, then try to disable it */
1289 	if (sn->use_gss_proxy == -1)
1290 		set_gss_proxy(net, 0);
1291 	return sn->use_gss_proxy;
1292 }
1293 
1294 #ifdef CONFIG_PROC_FS
1295 
1296 static ssize_t write_gssp(struct file *file, const char __user *buf,
1297 			 size_t count, loff_t *ppos)
1298 {
1299 	struct net *net = PDE_DATA(file_inode(file));
1300 	char tbuf[20];
1301 	unsigned long i;
1302 	int res;
1303 
1304 	if (*ppos || count > sizeof(tbuf)-1)
1305 		return -EINVAL;
1306 	if (copy_from_user(tbuf, buf, count))
1307 		return -EFAULT;
1308 
1309 	tbuf[count] = 0;
1310 	res = kstrtoul(tbuf, 0, &i);
1311 	if (res)
1312 		return res;
1313 	if (i != 1)
1314 		return -EINVAL;
1315 	res = set_gssp_clnt(net);
1316 	if (res)
1317 		return res;
1318 	res = set_gss_proxy(net, 1);
1319 	if (res)
1320 		return res;
1321 	return count;
1322 }
1323 
1324 static ssize_t read_gssp(struct file *file, char __user *buf,
1325 			 size_t count, loff_t *ppos)
1326 {
1327 	struct net *net = PDE_DATA(file_inode(file));
1328 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1329 	unsigned long p = *ppos;
1330 	char tbuf[10];
1331 	size_t len;
1332 
1333 	snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
1334 	len = strlen(tbuf);
1335 	if (p >= len)
1336 		return 0;
1337 	len -= p;
1338 	if (len > count)
1339 		len = count;
1340 	if (copy_to_user(buf, (void *)(tbuf+p), len))
1341 		return -EFAULT;
1342 	*ppos += len;
1343 	return len;
1344 }
1345 
1346 static const struct file_operations use_gss_proxy_ops = {
1347 	.open = nonseekable_open,
1348 	.write = write_gssp,
1349 	.read = read_gssp,
1350 };
1351 
1352 static int create_use_gss_proxy_proc_entry(struct net *net)
1353 {
1354 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1355 	struct proc_dir_entry **p = &sn->use_gssp_proc;
1356 
1357 	sn->use_gss_proxy = -1;
1358 	*p = proc_create_data("use-gss-proxy", S_IFREG|S_IRUSR|S_IWUSR,
1359 			      sn->proc_net_rpc,
1360 			      &use_gss_proxy_ops, net);
1361 	if (!*p)
1362 		return -ENOMEM;
1363 	init_gssp_clnt(sn);
1364 	return 0;
1365 }
1366 
1367 static void destroy_use_gss_proxy_proc_entry(struct net *net)
1368 {
1369 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1370 
1371 	if (sn->use_gssp_proc) {
1372 		remove_proc_entry("use-gss-proxy", sn->proc_net_rpc);
1373 		clear_gssp_clnt(sn);
1374 	}
1375 }
1376 #else /* CONFIG_PROC_FS */
1377 
1378 static int create_use_gss_proxy_proc_entry(struct net *net)
1379 {
1380 	return 0;
1381 }
1382 
1383 static void destroy_use_gss_proxy_proc_entry(struct net *net) {}
1384 
1385 #endif /* CONFIG_PROC_FS */
1386 
1387 /*
1388  * Accept an rpcsec packet.
1389  * If context establishment, punt to user space
1390  * If data exchange, verify/decrypt
1391  * If context destruction, handle here
1392  * In the context establishment and destruction case we encode
1393  * response here and return SVC_COMPLETE.
1394  */
1395 static int
1396 svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
1397 {
1398 	struct kvec	*argv = &rqstp->rq_arg.head[0];
1399 	struct kvec	*resv = &rqstp->rq_res.head[0];
1400 	u32		crlen;
1401 	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
1402 	struct rpc_gss_wire_cred *gc;
1403 	struct rsc	*rsci = NULL;
1404 	__be32		*rpcstart;
1405 	__be32		*reject_stat = resv->iov_base + resv->iov_len;
1406 	int		ret;
1407 	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1408 
1409 	dprintk("RPC:       svcauth_gss: argv->iov_len = %zd\n",
1410 			argv->iov_len);
1411 
1412 	*authp = rpc_autherr_badcred;
1413 	if (!svcdata)
1414 		svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL);
1415 	if (!svcdata)
1416 		goto auth_err;
1417 	rqstp->rq_auth_data = svcdata;
1418 	svcdata->verf_start = NULL;
1419 	svcdata->rsci = NULL;
1420 	gc = &svcdata->clcred;
1421 
1422 	/* start of rpc packet is 7 u32's back from here:
1423 	 * xid direction rpcversion prog vers proc flavour
1424 	 */
1425 	rpcstart = argv->iov_base;
1426 	rpcstart -= 7;
1427 
1428 	/* credential is:
1429 	 *   version(==1), proc(0,1,2,3), seq, service (1,2,3), handle
1430 	 * at least 5 u32s, and is preceded by length, so that makes 6.
1431 	 */
1432 
1433 	if (argv->iov_len < 5 * 4)
1434 		goto auth_err;
1435 	crlen = svc_getnl(argv);
1436 	if (svc_getnl(argv) != RPC_GSS_VERSION)
1437 		goto auth_err;
1438 	gc->gc_proc = svc_getnl(argv);
1439 	gc->gc_seq = svc_getnl(argv);
1440 	gc->gc_svc = svc_getnl(argv);
1441 	if (svc_safe_getnetobj(argv, &gc->gc_ctx))
1442 		goto auth_err;
1443 	if (crlen != round_up_to_quad(gc->gc_ctx.len) + 5 * 4)
1444 		goto auth_err;
1445 
1446 	if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0))
1447 		goto auth_err;
1448 
1449 	*authp = rpc_autherr_badverf;
1450 	switch (gc->gc_proc) {
1451 	case RPC_GSS_PROC_INIT:
1452 	case RPC_GSS_PROC_CONTINUE_INIT:
1453 		if (use_gss_proxy(SVC_NET(rqstp)))
1454 			return svcauth_gss_proxy_init(rqstp, gc, authp);
1455 		else
1456 			return svcauth_gss_legacy_init(rqstp, gc, authp);
1457 	case RPC_GSS_PROC_DATA:
1458 	case RPC_GSS_PROC_DESTROY:
1459 		/* Look up the context, and check the verifier: */
1460 		*authp = rpcsec_gsserr_credproblem;
1461 		rsci = gss_svc_searchbyctx(sn->rsc_cache, &gc->gc_ctx);
1462 		if (!rsci)
1463 			goto auth_err;
1464 		switch (gss_verify_header(rqstp, rsci, rpcstart, gc, authp)) {
1465 		case SVC_OK:
1466 			break;
1467 		case SVC_DENIED:
1468 			goto auth_err;
1469 		case SVC_DROP:
1470 			goto drop;
1471 		}
1472 		break;
1473 	default:
1474 		*authp = rpc_autherr_rejectedcred;
1475 		goto auth_err;
1476 	}
1477 
1478 	/* now act upon the command: */
1479 	switch (gc->gc_proc) {
1480 	case RPC_GSS_PROC_DESTROY:
1481 		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
1482 			goto auth_err;
1483 		rsci->h.expiry_time = get_seconds();
1484 		set_bit(CACHE_NEGATIVE, &rsci->h.flags);
1485 		if (resv->iov_len + 4 > PAGE_SIZE)
1486 			goto drop;
1487 		svc_putnl(resv, RPC_SUCCESS);
1488 		goto complete;
1489 	case RPC_GSS_PROC_DATA:
1490 		*authp = rpcsec_gsserr_ctxproblem;
1491 		svcdata->verf_start = resv->iov_base + resv->iov_len;
1492 		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
1493 			goto auth_err;
1494 		rqstp->rq_cred = rsci->cred;
1495 		get_group_info(rsci->cred.cr_group_info);
1496 		*authp = rpc_autherr_badcred;
1497 		switch (gc->gc_svc) {
1498 		case RPC_GSS_SVC_NONE:
1499 			break;
1500 		case RPC_GSS_SVC_INTEGRITY:
1501 			/* placeholders for length and seq. number: */
1502 			svc_putnl(resv, 0);
1503 			svc_putnl(resv, 0);
1504 			if (unwrap_integ_data(rqstp, &rqstp->rq_arg,
1505 					gc->gc_seq, rsci->mechctx))
1506 				goto garbage_args;
1507 			rqstp->rq_auth_slack = RPC_MAX_AUTH_SIZE;
1508 			break;
1509 		case RPC_GSS_SVC_PRIVACY:
1510 			/* placeholders for length and seq. number: */
1511 			svc_putnl(resv, 0);
1512 			svc_putnl(resv, 0);
1513 			if (unwrap_priv_data(rqstp, &rqstp->rq_arg,
1514 					gc->gc_seq, rsci->mechctx))
1515 				goto garbage_args;
1516 			rqstp->rq_auth_slack = RPC_MAX_AUTH_SIZE * 2;
1517 			break;
1518 		default:
1519 			goto auth_err;
1520 		}
1521 		svcdata->rsci = rsci;
1522 		cache_get(&rsci->h);
1523 		rqstp->rq_cred.cr_flavor = gss_svc_to_pseudoflavor(
1524 					rsci->mechctx->mech_type,
1525 					GSS_C_QOP_DEFAULT,
1526 					gc->gc_svc);
1527 		ret = SVC_OK;
1528 		goto out;
1529 	}
1530 garbage_args:
1531 	ret = SVC_GARBAGE;
1532 	goto out;
1533 auth_err:
1534 	/* Restore write pointer to its original value: */
1535 	xdr_ressize_check(rqstp, reject_stat);
1536 	ret = SVC_DENIED;
1537 	goto out;
1538 complete:
1539 	ret = SVC_COMPLETE;
1540 	goto out;
1541 drop:
1542 	ret = SVC_DROP;
1543 out:
1544 	if (rsci)
1545 		cache_put(&rsci->h, sn->rsc_cache);
1546 	return ret;
1547 }
1548 
1549 static __be32 *
1550 svcauth_gss_prepare_to_wrap(struct xdr_buf *resbuf, struct gss_svc_data *gsd)
1551 {
1552 	__be32 *p;
1553 	u32 verf_len;
1554 
1555 	p = gsd->verf_start;
1556 	gsd->verf_start = NULL;
1557 
1558 	/* If the reply stat is nonzero, don't wrap: */
1559 	if (*(p-1) != rpc_success)
1560 		return NULL;
1561 	/* Skip the verifier: */
1562 	p += 1;
1563 	verf_len = ntohl(*p++);
1564 	p += XDR_QUADLEN(verf_len);
1565 	/* move accept_stat to right place: */
1566 	memcpy(p, p + 2, 4);
1567 	/* Also don't wrap if the accept stat is nonzero: */
1568 	if (*p != rpc_success) {
1569 		resbuf->head[0].iov_len -= 2 * 4;
1570 		return NULL;
1571 	}
1572 	p++;
1573 	return p;
1574 }
1575 
1576 static inline int
1577 svcauth_gss_wrap_resp_integ(struct svc_rqst *rqstp)
1578 {
1579 	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1580 	struct rpc_gss_wire_cred *gc = &gsd->clcred;
1581 	struct xdr_buf *resbuf = &rqstp->rq_res;
1582 	struct xdr_buf integ_buf;
1583 	struct xdr_netobj mic;
1584 	struct kvec *resv;
1585 	__be32 *p;
1586 	int integ_offset, integ_len;
1587 	int stat = -EINVAL;
1588 
1589 	p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
1590 	if (p == NULL)
1591 		goto out;
1592 	integ_offset = (u8 *)(p + 1) - (u8 *)resbuf->head[0].iov_base;
1593 	integ_len = resbuf->len - integ_offset;
1594 	BUG_ON(integ_len % 4);
1595 	*p++ = htonl(integ_len);
1596 	*p++ = htonl(gc->gc_seq);
1597 	if (xdr_buf_subsegment(resbuf, &integ_buf, integ_offset, integ_len))
1598 		BUG();
1599 	if (resbuf->tail[0].iov_base == NULL) {
1600 		if (resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1601 			goto out_err;
1602 		resbuf->tail[0].iov_base = resbuf->head[0].iov_base
1603 						+ resbuf->head[0].iov_len;
1604 		resbuf->tail[0].iov_len = 0;
1605 	}
1606 	resv = &resbuf->tail[0];
1607 	mic.data = (u8 *)resv->iov_base + resv->iov_len + 4;
1608 	if (gss_get_mic(gsd->rsci->mechctx, &integ_buf, &mic))
1609 		goto out_err;
1610 	svc_putnl(resv, mic.len);
1611 	memset(mic.data + mic.len, 0,
1612 			round_up_to_quad(mic.len) - mic.len);
1613 	resv->iov_len += XDR_QUADLEN(mic.len) << 2;
1614 	/* not strictly required: */
1615 	resbuf->len += XDR_QUADLEN(mic.len) << 2;
1616 	BUG_ON(resv->iov_len > PAGE_SIZE);
1617 out:
1618 	stat = 0;
1619 out_err:
1620 	return stat;
1621 }
1622 
1623 static inline int
1624 svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp)
1625 {
1626 	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1627 	struct rpc_gss_wire_cred *gc = &gsd->clcred;
1628 	struct xdr_buf *resbuf = &rqstp->rq_res;
1629 	struct page **inpages = NULL;
1630 	__be32 *p, *len;
1631 	int offset;
1632 	int pad;
1633 
1634 	p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
1635 	if (p == NULL)
1636 		return 0;
1637 	len = p++;
1638 	offset = (u8 *)p - (u8 *)resbuf->head[0].iov_base;
1639 	*p++ = htonl(gc->gc_seq);
1640 	inpages = resbuf->pages;
1641 	/* XXX: Would be better to write some xdr helper functions for
1642 	 * nfs{2,3,4}xdr.c that place the data right, instead of copying: */
1643 
1644 	/*
1645 	 * If there is currently tail data, make sure there is
1646 	 * room for the head, tail, and 2 * RPC_MAX_AUTH_SIZE in
1647 	 * the page, and move the current tail data such that
1648 	 * there is RPC_MAX_AUTH_SIZE slack space available in
1649 	 * both the head and tail.
1650 	 */
1651 	if (resbuf->tail[0].iov_base) {
1652 		BUG_ON(resbuf->tail[0].iov_base >= resbuf->head[0].iov_base
1653 							+ PAGE_SIZE);
1654 		BUG_ON(resbuf->tail[0].iov_base < resbuf->head[0].iov_base);
1655 		if (resbuf->tail[0].iov_len + resbuf->head[0].iov_len
1656 				+ 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1657 			return -ENOMEM;
1658 		memmove(resbuf->tail[0].iov_base + RPC_MAX_AUTH_SIZE,
1659 			resbuf->tail[0].iov_base,
1660 			resbuf->tail[0].iov_len);
1661 		resbuf->tail[0].iov_base += RPC_MAX_AUTH_SIZE;
1662 	}
1663 	/*
1664 	 * If there is no current tail data, make sure there is
1665 	 * room for the head data, and 2 * RPC_MAX_AUTH_SIZE in the
1666 	 * allotted page, and set up tail information such that there
1667 	 * is RPC_MAX_AUTH_SIZE slack space available in both the
1668 	 * head and tail.
1669 	 */
1670 	if (resbuf->tail[0].iov_base == NULL) {
1671 		if (resbuf->head[0].iov_len + 2*RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1672 			return -ENOMEM;
1673 		resbuf->tail[0].iov_base = resbuf->head[0].iov_base
1674 			+ resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE;
1675 		resbuf->tail[0].iov_len = 0;
1676 	}
1677 	if (gss_wrap(gsd->rsci->mechctx, offset, resbuf, inpages))
1678 		return -ENOMEM;
1679 	*len = htonl(resbuf->len - offset);
1680 	pad = 3 - ((resbuf->len - offset - 1)&3);
1681 	p = (__be32 *)(resbuf->tail[0].iov_base + resbuf->tail[0].iov_len);
1682 	memset(p, 0, pad);
1683 	resbuf->tail[0].iov_len += pad;
1684 	resbuf->len += pad;
1685 	return 0;
1686 }
1687 
1688 static int
1689 svcauth_gss_release(struct svc_rqst *rqstp)
1690 {
1691 	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1692 	struct rpc_gss_wire_cred *gc = &gsd->clcred;
1693 	struct xdr_buf *resbuf = &rqstp->rq_res;
1694 	int stat = -EINVAL;
1695 	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1696 
1697 	if (gc->gc_proc != RPC_GSS_PROC_DATA)
1698 		goto out;
1699 	/* Release can be called twice, but we only wrap once. */
1700 	if (gsd->verf_start == NULL)
1701 		goto out;
1702 	/* normally not set till svc_send, but we need it here: */
1703 	/* XXX: what for?  Do we mess it up the moment we call svc_putu32
1704 	 * or whatever? */
1705 	resbuf->len = total_buf_len(resbuf);
1706 	switch (gc->gc_svc) {
1707 	case RPC_GSS_SVC_NONE:
1708 		break;
1709 	case RPC_GSS_SVC_INTEGRITY:
1710 		stat = svcauth_gss_wrap_resp_integ(rqstp);
1711 		if (stat)
1712 			goto out_err;
1713 		break;
1714 	case RPC_GSS_SVC_PRIVACY:
1715 		stat = svcauth_gss_wrap_resp_priv(rqstp);
1716 		if (stat)
1717 			goto out_err;
1718 		break;
1719 	/*
1720 	 * For any other gc_svc value, svcauth_gss_accept() already set
1721 	 * the auth_error appropriately; just fall through:
1722 	 */
1723 	}
1724 
1725 out:
1726 	stat = 0;
1727 out_err:
1728 	if (rqstp->rq_client)
1729 		auth_domain_put(rqstp->rq_client);
1730 	rqstp->rq_client = NULL;
1731 	if (rqstp->rq_gssclient)
1732 		auth_domain_put(rqstp->rq_gssclient);
1733 	rqstp->rq_gssclient = NULL;
1734 	if (rqstp->rq_cred.cr_group_info)
1735 		put_group_info(rqstp->rq_cred.cr_group_info);
1736 	rqstp->rq_cred.cr_group_info = NULL;
1737 	if (gsd->rsci)
1738 		cache_put(&gsd->rsci->h, sn->rsc_cache);
1739 	gsd->rsci = NULL;
1740 
1741 	return stat;
1742 }
1743 
1744 static void
1745 svcauth_gss_domain_release(struct auth_domain *dom)
1746 {
1747 	struct gss_domain *gd = container_of(dom, struct gss_domain, h);
1748 
1749 	kfree(dom->name);
1750 	kfree(gd);
1751 }
1752 
1753 static struct auth_ops svcauthops_gss = {
1754 	.name		= "rpcsec_gss",
1755 	.owner		= THIS_MODULE,
1756 	.flavour	= RPC_AUTH_GSS,
1757 	.accept		= svcauth_gss_accept,
1758 	.release	= svcauth_gss_release,
1759 	.domain_release = svcauth_gss_domain_release,
1760 	.set_client	= svcauth_gss_set_client,
1761 };
1762 
1763 static int rsi_cache_create_net(struct net *net)
1764 {
1765 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1766 	struct cache_detail *cd;
1767 	int err;
1768 
1769 	cd = cache_create_net(&rsi_cache_template, net);
1770 	if (IS_ERR(cd))
1771 		return PTR_ERR(cd);
1772 	err = cache_register_net(cd, net);
1773 	if (err) {
1774 		cache_destroy_net(cd, net);
1775 		return err;
1776 	}
1777 	sn->rsi_cache = cd;
1778 	return 0;
1779 }
1780 
1781 static void rsi_cache_destroy_net(struct net *net)
1782 {
1783 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1784 	struct cache_detail *cd = sn->rsi_cache;
1785 
1786 	sn->rsi_cache = NULL;
1787 	cache_purge(cd);
1788 	cache_unregister_net(cd, net);
1789 	cache_destroy_net(cd, net);
1790 }
1791 
1792 static int rsc_cache_create_net(struct net *net)
1793 {
1794 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1795 	struct cache_detail *cd;
1796 	int err;
1797 
1798 	cd = cache_create_net(&rsc_cache_template, net);
1799 	if (IS_ERR(cd))
1800 		return PTR_ERR(cd);
1801 	err = cache_register_net(cd, net);
1802 	if (err) {
1803 		cache_destroy_net(cd, net);
1804 		return err;
1805 	}
1806 	sn->rsc_cache = cd;
1807 	return 0;
1808 }
1809 
1810 static void rsc_cache_destroy_net(struct net *net)
1811 {
1812 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1813 	struct cache_detail *cd = sn->rsc_cache;
1814 
1815 	sn->rsc_cache = NULL;
1816 	cache_purge(cd);
1817 	cache_unregister_net(cd, net);
1818 	cache_destroy_net(cd, net);
1819 }
1820 
1821 int
1822 gss_svc_init_net(struct net *net)
1823 {
1824 	int rv;
1825 
1826 	rv = rsc_cache_create_net(net);
1827 	if (rv)
1828 		return rv;
1829 	rv = rsi_cache_create_net(net);
1830 	if (rv)
1831 		goto out1;
1832 	rv = create_use_gss_proxy_proc_entry(net);
1833 	if (rv)
1834 		goto out2;
1835 	return 0;
1836 out2:
1837 	destroy_use_gss_proxy_proc_entry(net);
1838 out1:
1839 	rsc_cache_destroy_net(net);
1840 	return rv;
1841 }
1842 
1843 void
1844 gss_svc_shutdown_net(struct net *net)
1845 {
1846 	destroy_use_gss_proxy_proc_entry(net);
1847 	rsi_cache_destroy_net(net);
1848 	rsc_cache_destroy_net(net);
1849 }
1850 
1851 int
1852 gss_svc_init(void)
1853 {
1854 	return svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss);
1855 }
1856 
1857 void
1858 gss_svc_shutdown(void)
1859 {
1860 	svc_auth_unregister(RPC_AUTH_GSS);
1861 }
1862