xref: /openbmc/linux/net/sunrpc/auth_gss/auth_gss.c (revision da2ef666)
1 /*
2  * linux/net/sunrpc/auth_gss/auth_gss.c
3  *
4  * RPCSEC_GSS client authentication.
5  *
6  *  Copyright (c) 2000 The Regents of the University of Michigan.
7  *  All rights reserved.
8  *
9  *  Dug Song       <dugsong@monkey.org>
10  *  Andy Adamson   <andros@umich.edu>
11  *
12  *  Redistribution and use in source and binary forms, with or without
13  *  modification, are permitted provided that the following conditions
14  *  are met:
15  *
16  *  1. Redistributions of source code must retain the above copyright
17  *     notice, this list of conditions and the following disclaimer.
18  *  2. Redistributions in binary form must reproduce the above copyright
19  *     notice, this list of conditions and the following disclaimer in the
20  *     documentation and/or other materials provided with the distribution.
21  *  3. Neither the name of the University nor the names of its
22  *     contributors may be used to endorse or promote products derived
23  *     from this software without specific prior written permission.
24  *
25  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
26  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
27  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
28  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
32  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 
39 #include <linux/module.h>
40 #include <linux/init.h>
41 #include <linux/types.h>
42 #include <linux/slab.h>
43 #include <linux/sched.h>
44 #include <linux/pagemap.h>
45 #include <linux/sunrpc/clnt.h>
46 #include <linux/sunrpc/auth.h>
47 #include <linux/sunrpc/auth_gss.h>
48 #include <linux/sunrpc/svcauth_gss.h>
49 #include <linux/sunrpc/gss_err.h>
50 #include <linux/workqueue.h>
51 #include <linux/sunrpc/rpc_pipe_fs.h>
52 #include <linux/sunrpc/gss_api.h>
53 #include <linux/uaccess.h>
54 #include <linux/hashtable.h>
55 
56 #include "../netns.h"
57 
58 static const struct rpc_authops authgss_ops;
59 
60 static const struct rpc_credops gss_credops;
61 static const struct rpc_credops gss_nullops;
62 
63 #define GSS_RETRY_EXPIRED 5
64 static unsigned int gss_expired_cred_retry_delay = GSS_RETRY_EXPIRED;
65 
66 #define GSS_KEY_EXPIRE_TIMEO 240
67 static unsigned int gss_key_expire_timeo = GSS_KEY_EXPIRE_TIMEO;
68 
69 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
70 # define RPCDBG_FACILITY	RPCDBG_AUTH
71 #endif
72 
73 #define GSS_CRED_SLACK		(RPC_MAX_AUTH_SIZE * 2)
74 /* length of a krb5 verifier (48), plus data added before arguments when
75  * using integrity (two 4-byte integers): */
76 #define GSS_VERF_SLACK		100
77 
78 static DEFINE_HASHTABLE(gss_auth_hash_table, 4);
79 static DEFINE_SPINLOCK(gss_auth_hash_lock);
80 
81 struct gss_pipe {
82 	struct rpc_pipe_dir_object pdo;
83 	struct rpc_pipe *pipe;
84 	struct rpc_clnt *clnt;
85 	const char *name;
86 	struct kref kref;
87 };
88 
89 struct gss_auth {
90 	struct kref kref;
91 	struct hlist_node hash;
92 	struct rpc_auth rpc_auth;
93 	struct gss_api_mech *mech;
94 	enum rpc_gss_svc service;
95 	struct rpc_clnt *client;
96 	struct net *net;
97 	/*
98 	 * There are two upcall pipes; dentry[1], named "gssd", is used
99 	 * for the new text-based upcall; dentry[0] is named after the
100 	 * mechanism (for example, "krb5") and exists for
101 	 * backwards-compatibility with older gssd's.
102 	 */
103 	struct gss_pipe *gss_pipe[2];
104 	const char *target_name;
105 };
106 
107 /* pipe_version >= 0 if and only if someone has a pipe open. */
108 static DEFINE_SPINLOCK(pipe_version_lock);
109 static struct rpc_wait_queue pipe_version_rpc_waitqueue;
110 static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
111 static void gss_put_auth(struct gss_auth *gss_auth);
112 
113 static void gss_free_ctx(struct gss_cl_ctx *);
114 static const struct rpc_pipe_ops gss_upcall_ops_v0;
115 static const struct rpc_pipe_ops gss_upcall_ops_v1;
116 
117 static inline struct gss_cl_ctx *
118 gss_get_ctx(struct gss_cl_ctx *ctx)
119 {
120 	refcount_inc(&ctx->count);
121 	return ctx;
122 }
123 
124 static inline void
125 gss_put_ctx(struct gss_cl_ctx *ctx)
126 {
127 	if (refcount_dec_and_test(&ctx->count))
128 		gss_free_ctx(ctx);
129 }
130 
131 /* gss_cred_set_ctx:
132  * called by gss_upcall_callback and gss_create_upcall in order
133  * to set the gss context. The actual exchange of an old context
134  * and a new one is protected by the pipe->lock.
135  */
136 static void
137 gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
138 {
139 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
140 
141 	if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
142 		return;
143 	gss_get_ctx(ctx);
144 	rcu_assign_pointer(gss_cred->gc_ctx, ctx);
145 	set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
146 	smp_mb__before_atomic();
147 	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
148 }
149 
150 static const void *
151 simple_get_bytes(const void *p, const void *end, void *res, size_t len)
152 {
153 	const void *q = (const void *)((const char *)p + len);
154 	if (unlikely(q > end || q < p))
155 		return ERR_PTR(-EFAULT);
156 	memcpy(res, p, len);
157 	return q;
158 }
159 
160 static inline const void *
161 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
162 {
163 	const void *q;
164 	unsigned int len;
165 
166 	p = simple_get_bytes(p, end, &len, sizeof(len));
167 	if (IS_ERR(p))
168 		return p;
169 	q = (const void *)((const char *)p + len);
170 	if (unlikely(q > end || q < p))
171 		return ERR_PTR(-EFAULT);
172 	dest->data = kmemdup(p, len, GFP_NOFS);
173 	if (unlikely(dest->data == NULL))
174 		return ERR_PTR(-ENOMEM);
175 	dest->len = len;
176 	return q;
177 }
178 
179 static struct gss_cl_ctx *
180 gss_cred_get_ctx(struct rpc_cred *cred)
181 {
182 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
183 	struct gss_cl_ctx *ctx = NULL;
184 
185 	rcu_read_lock();
186 	ctx = rcu_dereference(gss_cred->gc_ctx);
187 	if (ctx)
188 		gss_get_ctx(ctx);
189 	rcu_read_unlock();
190 	return ctx;
191 }
192 
193 static struct gss_cl_ctx *
194 gss_alloc_context(void)
195 {
196 	struct gss_cl_ctx *ctx;
197 
198 	ctx = kzalloc(sizeof(*ctx), GFP_NOFS);
199 	if (ctx != NULL) {
200 		ctx->gc_proc = RPC_GSS_PROC_DATA;
201 		ctx->gc_seq = 1;	/* NetApp 6.4R1 doesn't accept seq. no. 0 */
202 		spin_lock_init(&ctx->gc_seq_lock);
203 		refcount_set(&ctx->count,1);
204 	}
205 	return ctx;
206 }
207 
208 #define GSSD_MIN_TIMEOUT (60 * 60)
209 static const void *
210 gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
211 {
212 	const void *q;
213 	unsigned int seclen;
214 	unsigned int timeout;
215 	unsigned long now = jiffies;
216 	u32 window_size;
217 	int ret;
218 
219 	/* First unsigned int gives the remaining lifetime in seconds of the
220 	 * credential - e.g. the remaining TGT lifetime for Kerberos or
221 	 * the -t value passed to GSSD.
222 	 */
223 	p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
224 	if (IS_ERR(p))
225 		goto err;
226 	if (timeout == 0)
227 		timeout = GSSD_MIN_TIMEOUT;
228 	ctx->gc_expiry = now + ((unsigned long)timeout * HZ);
229 	/* Sequence number window. Determines the maximum number of
230 	 * simultaneous requests
231 	 */
232 	p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
233 	if (IS_ERR(p))
234 		goto err;
235 	ctx->gc_win = window_size;
236 	/* gssd signals an error by passing ctx->gc_win = 0: */
237 	if (ctx->gc_win == 0) {
238 		/*
239 		 * in which case, p points to an error code. Anything other
240 		 * than -EKEYEXPIRED gets converted to -EACCES.
241 		 */
242 		p = simple_get_bytes(p, end, &ret, sizeof(ret));
243 		if (!IS_ERR(p))
244 			p = (ret == -EKEYEXPIRED) ? ERR_PTR(-EKEYEXPIRED) :
245 						    ERR_PTR(-EACCES);
246 		goto err;
247 	}
248 	/* copy the opaque wire context */
249 	p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
250 	if (IS_ERR(p))
251 		goto err;
252 	/* import the opaque security context */
253 	p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
254 	if (IS_ERR(p))
255 		goto err;
256 	q = (const void *)((const char *)p + seclen);
257 	if (unlikely(q > end || q < p)) {
258 		p = ERR_PTR(-EFAULT);
259 		goto err;
260 	}
261 	ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx, NULL, GFP_NOFS);
262 	if (ret < 0) {
263 		p = ERR_PTR(ret);
264 		goto err;
265 	}
266 
267 	/* is there any trailing data? */
268 	if (q == end) {
269 		p = q;
270 		goto done;
271 	}
272 
273 	/* pull in acceptor name (if there is one) */
274 	p = simple_get_netobj(q, end, &ctx->gc_acceptor);
275 	if (IS_ERR(p))
276 		goto err;
277 done:
278 	dprintk("RPC:       %s Success. gc_expiry %lu now %lu timeout %u acceptor %.*s\n",
279 		__func__, ctx->gc_expiry, now, timeout, ctx->gc_acceptor.len,
280 		ctx->gc_acceptor.data);
281 	return p;
282 err:
283 	dprintk("RPC:       %s returns error %ld\n", __func__, -PTR_ERR(p));
284 	return p;
285 }
286 
287 /* XXX: Need some documentation about why UPCALL_BUF_LEN is so small.
288  *	Is user space expecting no more than UPCALL_BUF_LEN bytes?
289  *	Note that there are now _two_ NI_MAXHOST sized data items
290  *	being passed in this string.
291  */
292 #define UPCALL_BUF_LEN	256
293 
294 struct gss_upcall_msg {
295 	refcount_t count;
296 	kuid_t	uid;
297 	struct rpc_pipe_msg msg;
298 	struct list_head list;
299 	struct gss_auth *auth;
300 	struct rpc_pipe *pipe;
301 	struct rpc_wait_queue rpc_waitqueue;
302 	wait_queue_head_t waitqueue;
303 	struct gss_cl_ctx *ctx;
304 	char databuf[UPCALL_BUF_LEN];
305 };
306 
307 static int get_pipe_version(struct net *net)
308 {
309 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
310 	int ret;
311 
312 	spin_lock(&pipe_version_lock);
313 	if (sn->pipe_version >= 0) {
314 		atomic_inc(&sn->pipe_users);
315 		ret = sn->pipe_version;
316 	} else
317 		ret = -EAGAIN;
318 	spin_unlock(&pipe_version_lock);
319 	return ret;
320 }
321 
322 static void put_pipe_version(struct net *net)
323 {
324 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
325 
326 	if (atomic_dec_and_lock(&sn->pipe_users, &pipe_version_lock)) {
327 		sn->pipe_version = -1;
328 		spin_unlock(&pipe_version_lock);
329 	}
330 }
331 
332 static void
333 gss_release_msg(struct gss_upcall_msg *gss_msg)
334 {
335 	struct net *net = gss_msg->auth->net;
336 	if (!refcount_dec_and_test(&gss_msg->count))
337 		return;
338 	put_pipe_version(net);
339 	BUG_ON(!list_empty(&gss_msg->list));
340 	if (gss_msg->ctx != NULL)
341 		gss_put_ctx(gss_msg->ctx);
342 	rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
343 	gss_put_auth(gss_msg->auth);
344 	kfree(gss_msg);
345 }
346 
347 static struct gss_upcall_msg *
348 __gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid, const struct gss_auth *auth)
349 {
350 	struct gss_upcall_msg *pos;
351 	list_for_each_entry(pos, &pipe->in_downcall, list) {
352 		if (!uid_eq(pos->uid, uid))
353 			continue;
354 		if (auth && pos->auth->service != auth->service)
355 			continue;
356 		refcount_inc(&pos->count);
357 		dprintk("RPC:       %s found msg %p\n", __func__, pos);
358 		return pos;
359 	}
360 	dprintk("RPC:       %s found nothing\n", __func__);
361 	return NULL;
362 }
363 
364 /* Try to add an upcall to the pipefs queue.
365  * If an upcall owned by our uid already exists, then we return a reference
366  * to that upcall instead of adding the new upcall.
367  */
368 static inline struct gss_upcall_msg *
369 gss_add_msg(struct gss_upcall_msg *gss_msg)
370 {
371 	struct rpc_pipe *pipe = gss_msg->pipe;
372 	struct gss_upcall_msg *old;
373 
374 	spin_lock(&pipe->lock);
375 	old = __gss_find_upcall(pipe, gss_msg->uid, gss_msg->auth);
376 	if (old == NULL) {
377 		refcount_inc(&gss_msg->count);
378 		list_add(&gss_msg->list, &pipe->in_downcall);
379 	} else
380 		gss_msg = old;
381 	spin_unlock(&pipe->lock);
382 	return gss_msg;
383 }
384 
385 static void
386 __gss_unhash_msg(struct gss_upcall_msg *gss_msg)
387 {
388 	list_del_init(&gss_msg->list);
389 	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
390 	wake_up_all(&gss_msg->waitqueue);
391 	refcount_dec(&gss_msg->count);
392 }
393 
394 static void
395 gss_unhash_msg(struct gss_upcall_msg *gss_msg)
396 {
397 	struct rpc_pipe *pipe = gss_msg->pipe;
398 
399 	if (list_empty(&gss_msg->list))
400 		return;
401 	spin_lock(&pipe->lock);
402 	if (!list_empty(&gss_msg->list))
403 		__gss_unhash_msg(gss_msg);
404 	spin_unlock(&pipe->lock);
405 }
406 
407 static void
408 gss_handle_downcall_result(struct gss_cred *gss_cred, struct gss_upcall_msg *gss_msg)
409 {
410 	switch (gss_msg->msg.errno) {
411 	case 0:
412 		if (gss_msg->ctx == NULL)
413 			break;
414 		clear_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
415 		gss_cred_set_ctx(&gss_cred->gc_base, gss_msg->ctx);
416 		break;
417 	case -EKEYEXPIRED:
418 		set_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
419 	}
420 	gss_cred->gc_upcall_timestamp = jiffies;
421 	gss_cred->gc_upcall = NULL;
422 	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
423 }
424 
425 static void
426 gss_upcall_callback(struct rpc_task *task)
427 {
428 	struct gss_cred *gss_cred = container_of(task->tk_rqstp->rq_cred,
429 			struct gss_cred, gc_base);
430 	struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
431 	struct rpc_pipe *pipe = gss_msg->pipe;
432 
433 	spin_lock(&pipe->lock);
434 	gss_handle_downcall_result(gss_cred, gss_msg);
435 	spin_unlock(&pipe->lock);
436 	task->tk_status = gss_msg->msg.errno;
437 	gss_release_msg(gss_msg);
438 }
439 
440 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
441 {
442 	uid_t uid = from_kuid(&init_user_ns, gss_msg->uid);
443 	memcpy(gss_msg->databuf, &uid, sizeof(uid));
444 	gss_msg->msg.data = gss_msg->databuf;
445 	gss_msg->msg.len = sizeof(uid);
446 
447 	BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
448 }
449 
450 static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
451 				const char *service_name,
452 				const char *target_name)
453 {
454 	struct gss_api_mech *mech = gss_msg->auth->mech;
455 	char *p = gss_msg->databuf;
456 	size_t buflen = sizeof(gss_msg->databuf);
457 	int len;
458 
459 	len = scnprintf(p, buflen, "mech=%s uid=%d ", mech->gm_name,
460 			from_kuid(&init_user_ns, gss_msg->uid));
461 	buflen -= len;
462 	p += len;
463 	gss_msg->msg.len = len;
464 
465 	/*
466 	 * target= is a full service principal that names the remote
467 	 * identity that we are authenticating to.
468 	 */
469 	if (target_name) {
470 		len = scnprintf(p, buflen, "target=%s ", target_name);
471 		buflen -= len;
472 		p += len;
473 		gss_msg->msg.len += len;
474 	}
475 
476 	/*
477 	 * gssd uses service= and srchost= to select a matching key from
478 	 * the system's keytab to use as the source principal.
479 	 *
480 	 * service= is the service name part of the source principal,
481 	 * or "*" (meaning choose any).
482 	 *
483 	 * srchost= is the hostname part of the source principal. When
484 	 * not provided, gssd uses the local hostname.
485 	 */
486 	if (service_name) {
487 		char *c = strchr(service_name, '@');
488 
489 		if (!c)
490 			len = scnprintf(p, buflen, "service=%s ",
491 					service_name);
492 		else
493 			len = scnprintf(p, buflen,
494 					"service=%.*s srchost=%s ",
495 					(int)(c - service_name),
496 					service_name, c + 1);
497 		buflen -= len;
498 		p += len;
499 		gss_msg->msg.len += len;
500 	}
501 
502 	if (mech->gm_upcall_enctypes) {
503 		len = scnprintf(p, buflen, "enctypes=%s ",
504 				mech->gm_upcall_enctypes);
505 		buflen -= len;
506 		p += len;
507 		gss_msg->msg.len += len;
508 	}
509 	len = scnprintf(p, buflen, "\n");
510 	if (len == 0)
511 		goto out_overflow;
512 	gss_msg->msg.len += len;
513 
514 	gss_msg->msg.data = gss_msg->databuf;
515 	return 0;
516 out_overflow:
517 	WARN_ON_ONCE(1);
518 	return -ENOMEM;
519 }
520 
521 static struct gss_upcall_msg *
522 gss_alloc_msg(struct gss_auth *gss_auth,
523 		kuid_t uid, const char *service_name)
524 {
525 	struct gss_upcall_msg *gss_msg;
526 	int vers;
527 	int err = -ENOMEM;
528 
529 	gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
530 	if (gss_msg == NULL)
531 		goto err;
532 	vers = get_pipe_version(gss_auth->net);
533 	err = vers;
534 	if (err < 0)
535 		goto err_free_msg;
536 	gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
537 	INIT_LIST_HEAD(&gss_msg->list);
538 	rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
539 	init_waitqueue_head(&gss_msg->waitqueue);
540 	refcount_set(&gss_msg->count, 1);
541 	gss_msg->uid = uid;
542 	gss_msg->auth = gss_auth;
543 	switch (vers) {
544 	case 0:
545 		gss_encode_v0_msg(gss_msg);
546 		break;
547 	default:
548 		err = gss_encode_v1_msg(gss_msg, service_name, gss_auth->target_name);
549 		if (err)
550 			goto err_put_pipe_version;
551 	}
552 	kref_get(&gss_auth->kref);
553 	return gss_msg;
554 err_put_pipe_version:
555 	put_pipe_version(gss_auth->net);
556 err_free_msg:
557 	kfree(gss_msg);
558 err:
559 	return ERR_PTR(err);
560 }
561 
562 static struct gss_upcall_msg *
563 gss_setup_upcall(struct gss_auth *gss_auth, struct rpc_cred *cred)
564 {
565 	struct gss_cred *gss_cred = container_of(cred,
566 			struct gss_cred, gc_base);
567 	struct gss_upcall_msg *gss_new, *gss_msg;
568 	kuid_t uid = cred->cr_uid;
569 
570 	gss_new = gss_alloc_msg(gss_auth, uid, gss_cred->gc_principal);
571 	if (IS_ERR(gss_new))
572 		return gss_new;
573 	gss_msg = gss_add_msg(gss_new);
574 	if (gss_msg == gss_new) {
575 		int res;
576 		refcount_inc(&gss_msg->count);
577 		res = rpc_queue_upcall(gss_new->pipe, &gss_new->msg);
578 		if (res) {
579 			gss_unhash_msg(gss_new);
580 			refcount_dec(&gss_msg->count);
581 			gss_release_msg(gss_new);
582 			gss_msg = ERR_PTR(res);
583 		}
584 	} else
585 		gss_release_msg(gss_new);
586 	return gss_msg;
587 }
588 
589 static void warn_gssd(void)
590 {
591 	dprintk("AUTH_GSS upcall failed. Please check user daemon is running.\n");
592 }
593 
594 static inline int
595 gss_refresh_upcall(struct rpc_task *task)
596 {
597 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
598 	struct gss_auth *gss_auth = container_of(cred->cr_auth,
599 			struct gss_auth, rpc_auth);
600 	struct gss_cred *gss_cred = container_of(cred,
601 			struct gss_cred, gc_base);
602 	struct gss_upcall_msg *gss_msg;
603 	struct rpc_pipe *pipe;
604 	int err = 0;
605 
606 	dprintk("RPC: %5u %s for uid %u\n",
607 		task->tk_pid, __func__, from_kuid(&init_user_ns, cred->cr_uid));
608 	gss_msg = gss_setup_upcall(gss_auth, cred);
609 	if (PTR_ERR(gss_msg) == -EAGAIN) {
610 		/* XXX: warning on the first, under the assumption we
611 		 * shouldn't normally hit this case on a refresh. */
612 		warn_gssd();
613 		task->tk_timeout = 15*HZ;
614 		rpc_sleep_on(&pipe_version_rpc_waitqueue, task, NULL);
615 		return -EAGAIN;
616 	}
617 	if (IS_ERR(gss_msg)) {
618 		err = PTR_ERR(gss_msg);
619 		goto out;
620 	}
621 	pipe = gss_msg->pipe;
622 	spin_lock(&pipe->lock);
623 	if (gss_cred->gc_upcall != NULL)
624 		rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);
625 	else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
626 		task->tk_timeout = 0;
627 		gss_cred->gc_upcall = gss_msg;
628 		/* gss_upcall_callback will release the reference to gss_upcall_msg */
629 		refcount_inc(&gss_msg->count);
630 		rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback);
631 	} else {
632 		gss_handle_downcall_result(gss_cred, gss_msg);
633 		err = gss_msg->msg.errno;
634 	}
635 	spin_unlock(&pipe->lock);
636 	gss_release_msg(gss_msg);
637 out:
638 	dprintk("RPC: %5u %s for uid %u result %d\n",
639 		task->tk_pid, __func__,
640 		from_kuid(&init_user_ns, cred->cr_uid),	err);
641 	return err;
642 }
643 
644 static inline int
645 gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
646 {
647 	struct net *net = gss_auth->net;
648 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
649 	struct rpc_pipe *pipe;
650 	struct rpc_cred *cred = &gss_cred->gc_base;
651 	struct gss_upcall_msg *gss_msg;
652 	DEFINE_WAIT(wait);
653 	int err;
654 
655 	dprintk("RPC:       %s for uid %u\n",
656 		__func__, from_kuid(&init_user_ns, cred->cr_uid));
657 retry:
658 	err = 0;
659 	/* if gssd is down, just skip upcalling altogether */
660 	if (!gssd_running(net)) {
661 		warn_gssd();
662 		return -EACCES;
663 	}
664 	gss_msg = gss_setup_upcall(gss_auth, cred);
665 	if (PTR_ERR(gss_msg) == -EAGAIN) {
666 		err = wait_event_interruptible_timeout(pipe_version_waitqueue,
667 				sn->pipe_version >= 0, 15 * HZ);
668 		if (sn->pipe_version < 0) {
669 			warn_gssd();
670 			err = -EACCES;
671 		}
672 		if (err < 0)
673 			goto out;
674 		goto retry;
675 	}
676 	if (IS_ERR(gss_msg)) {
677 		err = PTR_ERR(gss_msg);
678 		goto out;
679 	}
680 	pipe = gss_msg->pipe;
681 	for (;;) {
682 		prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_KILLABLE);
683 		spin_lock(&pipe->lock);
684 		if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
685 			break;
686 		}
687 		spin_unlock(&pipe->lock);
688 		if (fatal_signal_pending(current)) {
689 			err = -ERESTARTSYS;
690 			goto out_intr;
691 		}
692 		schedule();
693 	}
694 	if (gss_msg->ctx)
695 		gss_cred_set_ctx(cred, gss_msg->ctx);
696 	else
697 		err = gss_msg->msg.errno;
698 	spin_unlock(&pipe->lock);
699 out_intr:
700 	finish_wait(&gss_msg->waitqueue, &wait);
701 	gss_release_msg(gss_msg);
702 out:
703 	dprintk("RPC:       %s for uid %u result %d\n",
704 		__func__, from_kuid(&init_user_ns, cred->cr_uid), err);
705 	return err;
706 }
707 
708 #define MSG_BUF_MAXSIZE 1024
709 
710 static ssize_t
711 gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
712 {
713 	const void *p, *end;
714 	void *buf;
715 	struct gss_upcall_msg *gss_msg;
716 	struct rpc_pipe *pipe = RPC_I(file_inode(filp))->pipe;
717 	struct gss_cl_ctx *ctx;
718 	uid_t id;
719 	kuid_t uid;
720 	ssize_t err = -EFBIG;
721 
722 	if (mlen > MSG_BUF_MAXSIZE)
723 		goto out;
724 	err = -ENOMEM;
725 	buf = kmalloc(mlen, GFP_NOFS);
726 	if (!buf)
727 		goto out;
728 
729 	err = -EFAULT;
730 	if (copy_from_user(buf, src, mlen))
731 		goto err;
732 
733 	end = (const void *)((char *)buf + mlen);
734 	p = simple_get_bytes(buf, end, &id, sizeof(id));
735 	if (IS_ERR(p)) {
736 		err = PTR_ERR(p);
737 		goto err;
738 	}
739 
740 	uid = make_kuid(&init_user_ns, id);
741 	if (!uid_valid(uid)) {
742 		err = -EINVAL;
743 		goto err;
744 	}
745 
746 	err = -ENOMEM;
747 	ctx = gss_alloc_context();
748 	if (ctx == NULL)
749 		goto err;
750 
751 	err = -ENOENT;
752 	/* Find a matching upcall */
753 	spin_lock(&pipe->lock);
754 	gss_msg = __gss_find_upcall(pipe, uid, NULL);
755 	if (gss_msg == NULL) {
756 		spin_unlock(&pipe->lock);
757 		goto err_put_ctx;
758 	}
759 	list_del_init(&gss_msg->list);
760 	spin_unlock(&pipe->lock);
761 
762 	p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
763 	if (IS_ERR(p)) {
764 		err = PTR_ERR(p);
765 		switch (err) {
766 		case -EACCES:
767 		case -EKEYEXPIRED:
768 			gss_msg->msg.errno = err;
769 			err = mlen;
770 			break;
771 		case -EFAULT:
772 		case -ENOMEM:
773 		case -EINVAL:
774 		case -ENOSYS:
775 			gss_msg->msg.errno = -EAGAIN;
776 			break;
777 		default:
778 			printk(KERN_CRIT "%s: bad return from "
779 				"gss_fill_context: %zd\n", __func__, err);
780 			gss_msg->msg.errno = -EIO;
781 		}
782 		goto err_release_msg;
783 	}
784 	gss_msg->ctx = gss_get_ctx(ctx);
785 	err = mlen;
786 
787 err_release_msg:
788 	spin_lock(&pipe->lock);
789 	__gss_unhash_msg(gss_msg);
790 	spin_unlock(&pipe->lock);
791 	gss_release_msg(gss_msg);
792 err_put_ctx:
793 	gss_put_ctx(ctx);
794 err:
795 	kfree(buf);
796 out:
797 	dprintk("RPC:       %s returning %zd\n", __func__, err);
798 	return err;
799 }
800 
801 static int gss_pipe_open(struct inode *inode, int new_version)
802 {
803 	struct net *net = inode->i_sb->s_fs_info;
804 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
805 	int ret = 0;
806 
807 	spin_lock(&pipe_version_lock);
808 	if (sn->pipe_version < 0) {
809 		/* First open of any gss pipe determines the version: */
810 		sn->pipe_version = new_version;
811 		rpc_wake_up(&pipe_version_rpc_waitqueue);
812 		wake_up(&pipe_version_waitqueue);
813 	} else if (sn->pipe_version != new_version) {
814 		/* Trying to open a pipe of a different version */
815 		ret = -EBUSY;
816 		goto out;
817 	}
818 	atomic_inc(&sn->pipe_users);
819 out:
820 	spin_unlock(&pipe_version_lock);
821 	return ret;
822 
823 }
824 
825 static int gss_pipe_open_v0(struct inode *inode)
826 {
827 	return gss_pipe_open(inode, 0);
828 }
829 
830 static int gss_pipe_open_v1(struct inode *inode)
831 {
832 	return gss_pipe_open(inode, 1);
833 }
834 
835 static void
836 gss_pipe_release(struct inode *inode)
837 {
838 	struct net *net = inode->i_sb->s_fs_info;
839 	struct rpc_pipe *pipe = RPC_I(inode)->pipe;
840 	struct gss_upcall_msg *gss_msg;
841 
842 restart:
843 	spin_lock(&pipe->lock);
844 	list_for_each_entry(gss_msg, &pipe->in_downcall, list) {
845 
846 		if (!list_empty(&gss_msg->msg.list))
847 			continue;
848 		gss_msg->msg.errno = -EPIPE;
849 		refcount_inc(&gss_msg->count);
850 		__gss_unhash_msg(gss_msg);
851 		spin_unlock(&pipe->lock);
852 		gss_release_msg(gss_msg);
853 		goto restart;
854 	}
855 	spin_unlock(&pipe->lock);
856 
857 	put_pipe_version(net);
858 }
859 
860 static void
861 gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
862 {
863 	struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
864 
865 	if (msg->errno < 0) {
866 		dprintk("RPC:       %s releasing msg %p\n",
867 			__func__, gss_msg);
868 		refcount_inc(&gss_msg->count);
869 		gss_unhash_msg(gss_msg);
870 		if (msg->errno == -ETIMEDOUT)
871 			warn_gssd();
872 		gss_release_msg(gss_msg);
873 	}
874 	gss_release_msg(gss_msg);
875 }
876 
877 static void gss_pipe_dentry_destroy(struct dentry *dir,
878 		struct rpc_pipe_dir_object *pdo)
879 {
880 	struct gss_pipe *gss_pipe = pdo->pdo_data;
881 	struct rpc_pipe *pipe = gss_pipe->pipe;
882 
883 	if (pipe->dentry != NULL) {
884 		rpc_unlink(pipe->dentry);
885 		pipe->dentry = NULL;
886 	}
887 }
888 
889 static int gss_pipe_dentry_create(struct dentry *dir,
890 		struct rpc_pipe_dir_object *pdo)
891 {
892 	struct gss_pipe *p = pdo->pdo_data;
893 	struct dentry *dentry;
894 
895 	dentry = rpc_mkpipe_dentry(dir, p->name, p->clnt, p->pipe);
896 	if (IS_ERR(dentry))
897 		return PTR_ERR(dentry);
898 	p->pipe->dentry = dentry;
899 	return 0;
900 }
901 
902 static const struct rpc_pipe_dir_object_ops gss_pipe_dir_object_ops = {
903 	.create = gss_pipe_dentry_create,
904 	.destroy = gss_pipe_dentry_destroy,
905 };
906 
907 static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
908 		const char *name,
909 		const struct rpc_pipe_ops *upcall_ops)
910 {
911 	struct gss_pipe *p;
912 	int err = -ENOMEM;
913 
914 	p = kmalloc(sizeof(*p), GFP_KERNEL);
915 	if (p == NULL)
916 		goto err;
917 	p->pipe = rpc_mkpipe_data(upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
918 	if (IS_ERR(p->pipe)) {
919 		err = PTR_ERR(p->pipe);
920 		goto err_free_gss_pipe;
921 	}
922 	p->name = name;
923 	p->clnt = clnt;
924 	kref_init(&p->kref);
925 	rpc_init_pipe_dir_object(&p->pdo,
926 			&gss_pipe_dir_object_ops,
927 			p);
928 	return p;
929 err_free_gss_pipe:
930 	kfree(p);
931 err:
932 	return ERR_PTR(err);
933 }
934 
935 struct gss_alloc_pdo {
936 	struct rpc_clnt *clnt;
937 	const char *name;
938 	const struct rpc_pipe_ops *upcall_ops;
939 };
940 
941 static int gss_pipe_match_pdo(struct rpc_pipe_dir_object *pdo, void *data)
942 {
943 	struct gss_pipe *gss_pipe;
944 	struct gss_alloc_pdo *args = data;
945 
946 	if (pdo->pdo_ops != &gss_pipe_dir_object_ops)
947 		return 0;
948 	gss_pipe = container_of(pdo, struct gss_pipe, pdo);
949 	if (strcmp(gss_pipe->name, args->name) != 0)
950 		return 0;
951 	if (!kref_get_unless_zero(&gss_pipe->kref))
952 		return 0;
953 	return 1;
954 }
955 
956 static struct rpc_pipe_dir_object *gss_pipe_alloc_pdo(void *data)
957 {
958 	struct gss_pipe *gss_pipe;
959 	struct gss_alloc_pdo *args = data;
960 
961 	gss_pipe = gss_pipe_alloc(args->clnt, args->name, args->upcall_ops);
962 	if (!IS_ERR(gss_pipe))
963 		return &gss_pipe->pdo;
964 	return NULL;
965 }
966 
967 static struct gss_pipe *gss_pipe_get(struct rpc_clnt *clnt,
968 		const char *name,
969 		const struct rpc_pipe_ops *upcall_ops)
970 {
971 	struct net *net = rpc_net_ns(clnt);
972 	struct rpc_pipe_dir_object *pdo;
973 	struct gss_alloc_pdo args = {
974 		.clnt = clnt,
975 		.name = name,
976 		.upcall_ops = upcall_ops,
977 	};
978 
979 	pdo = rpc_find_or_alloc_pipe_dir_object(net,
980 			&clnt->cl_pipedir_objects,
981 			gss_pipe_match_pdo,
982 			gss_pipe_alloc_pdo,
983 			&args);
984 	if (pdo != NULL)
985 		return container_of(pdo, struct gss_pipe, pdo);
986 	return ERR_PTR(-ENOMEM);
987 }
988 
989 static void __gss_pipe_free(struct gss_pipe *p)
990 {
991 	struct rpc_clnt *clnt = p->clnt;
992 	struct net *net = rpc_net_ns(clnt);
993 
994 	rpc_remove_pipe_dir_object(net,
995 			&clnt->cl_pipedir_objects,
996 			&p->pdo);
997 	rpc_destroy_pipe_data(p->pipe);
998 	kfree(p);
999 }
1000 
1001 static void __gss_pipe_release(struct kref *kref)
1002 {
1003 	struct gss_pipe *p = container_of(kref, struct gss_pipe, kref);
1004 
1005 	__gss_pipe_free(p);
1006 }
1007 
1008 static void gss_pipe_free(struct gss_pipe *p)
1009 {
1010 	if (p != NULL)
1011 		kref_put(&p->kref, __gss_pipe_release);
1012 }
1013 
1014 /*
1015  * NOTE: we have the opportunity to use different
1016  * parameters based on the input flavor (which must be a pseudoflavor)
1017  */
1018 static struct gss_auth *
1019 gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1020 {
1021 	rpc_authflavor_t flavor = args->pseudoflavor;
1022 	struct gss_auth *gss_auth;
1023 	struct gss_pipe *gss_pipe;
1024 	struct rpc_auth * auth;
1025 	int err = -ENOMEM; /* XXX? */
1026 
1027 	dprintk("RPC:       creating GSS authenticator for client %p\n", clnt);
1028 
1029 	if (!try_module_get(THIS_MODULE))
1030 		return ERR_PTR(err);
1031 	if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
1032 		goto out_dec;
1033 	INIT_HLIST_NODE(&gss_auth->hash);
1034 	gss_auth->target_name = NULL;
1035 	if (args->target_name) {
1036 		gss_auth->target_name = kstrdup(args->target_name, GFP_KERNEL);
1037 		if (gss_auth->target_name == NULL)
1038 			goto err_free;
1039 	}
1040 	gss_auth->client = clnt;
1041 	gss_auth->net = get_net(rpc_net_ns(clnt));
1042 	err = -EINVAL;
1043 	gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
1044 	if (!gss_auth->mech) {
1045 		dprintk("RPC:       Pseudoflavor %d not found!\n", flavor);
1046 		goto err_put_net;
1047 	}
1048 	gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
1049 	if (gss_auth->service == 0)
1050 		goto err_put_mech;
1051 	if (!gssd_running(gss_auth->net))
1052 		goto err_put_mech;
1053 	auth = &gss_auth->rpc_auth;
1054 	auth->au_cslack = GSS_CRED_SLACK >> 2;
1055 	auth->au_rslack = GSS_VERF_SLACK >> 2;
1056 	auth->au_flags = 0;
1057 	auth->au_ops = &authgss_ops;
1058 	auth->au_flavor = flavor;
1059 	if (gss_pseudoflavor_to_datatouch(gss_auth->mech, flavor))
1060 		auth->au_flags |= RPCAUTH_AUTH_DATATOUCH;
1061 	atomic_set(&auth->au_count, 1);
1062 	kref_init(&gss_auth->kref);
1063 
1064 	err = rpcauth_init_credcache(auth);
1065 	if (err)
1066 		goto err_put_mech;
1067 	/*
1068 	 * Note: if we created the old pipe first, then someone who
1069 	 * examined the directory at the right moment might conclude
1070 	 * that we supported only the old pipe.  So we instead create
1071 	 * the new pipe first.
1072 	 */
1073 	gss_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
1074 	if (IS_ERR(gss_pipe)) {
1075 		err = PTR_ERR(gss_pipe);
1076 		goto err_destroy_credcache;
1077 	}
1078 	gss_auth->gss_pipe[1] = gss_pipe;
1079 
1080 	gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
1081 			&gss_upcall_ops_v0);
1082 	if (IS_ERR(gss_pipe)) {
1083 		err = PTR_ERR(gss_pipe);
1084 		goto err_destroy_pipe_1;
1085 	}
1086 	gss_auth->gss_pipe[0] = gss_pipe;
1087 
1088 	return gss_auth;
1089 err_destroy_pipe_1:
1090 	gss_pipe_free(gss_auth->gss_pipe[1]);
1091 err_destroy_credcache:
1092 	rpcauth_destroy_credcache(auth);
1093 err_put_mech:
1094 	gss_mech_put(gss_auth->mech);
1095 err_put_net:
1096 	put_net(gss_auth->net);
1097 err_free:
1098 	kfree(gss_auth->target_name);
1099 	kfree(gss_auth);
1100 out_dec:
1101 	module_put(THIS_MODULE);
1102 	return ERR_PTR(err);
1103 }
1104 
1105 static void
1106 gss_free(struct gss_auth *gss_auth)
1107 {
1108 	gss_pipe_free(gss_auth->gss_pipe[0]);
1109 	gss_pipe_free(gss_auth->gss_pipe[1]);
1110 	gss_mech_put(gss_auth->mech);
1111 	put_net(gss_auth->net);
1112 	kfree(gss_auth->target_name);
1113 
1114 	kfree(gss_auth);
1115 	module_put(THIS_MODULE);
1116 }
1117 
1118 static void
1119 gss_free_callback(struct kref *kref)
1120 {
1121 	struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
1122 
1123 	gss_free(gss_auth);
1124 }
1125 
1126 static void
1127 gss_put_auth(struct gss_auth *gss_auth)
1128 {
1129 	kref_put(&gss_auth->kref, gss_free_callback);
1130 }
1131 
1132 static void
1133 gss_destroy(struct rpc_auth *auth)
1134 {
1135 	struct gss_auth *gss_auth = container_of(auth,
1136 			struct gss_auth, rpc_auth);
1137 
1138 	dprintk("RPC:       destroying GSS authenticator %p flavor %d\n",
1139 			auth, auth->au_flavor);
1140 
1141 	if (hash_hashed(&gss_auth->hash)) {
1142 		spin_lock(&gss_auth_hash_lock);
1143 		hash_del(&gss_auth->hash);
1144 		spin_unlock(&gss_auth_hash_lock);
1145 	}
1146 
1147 	gss_pipe_free(gss_auth->gss_pipe[0]);
1148 	gss_auth->gss_pipe[0] = NULL;
1149 	gss_pipe_free(gss_auth->gss_pipe[1]);
1150 	gss_auth->gss_pipe[1] = NULL;
1151 	rpcauth_destroy_credcache(auth);
1152 
1153 	gss_put_auth(gss_auth);
1154 }
1155 
1156 /*
1157  * Auths may be shared between rpc clients that were cloned from a
1158  * common client with the same xprt, if they also share the flavor and
1159  * target_name.
1160  *
1161  * The auth is looked up from the oldest parent sharing the same
1162  * cl_xprt, and the auth itself references only that common parent
1163  * (which is guaranteed to last as long as any of its descendants).
1164  */
1165 static struct gss_auth *
1166 gss_auth_find_or_add_hashed(const struct rpc_auth_create_args *args,
1167 		struct rpc_clnt *clnt,
1168 		struct gss_auth *new)
1169 {
1170 	struct gss_auth *gss_auth;
1171 	unsigned long hashval = (unsigned long)clnt;
1172 
1173 	spin_lock(&gss_auth_hash_lock);
1174 	hash_for_each_possible(gss_auth_hash_table,
1175 			gss_auth,
1176 			hash,
1177 			hashval) {
1178 		if (gss_auth->client != clnt)
1179 			continue;
1180 		if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor)
1181 			continue;
1182 		if (gss_auth->target_name != args->target_name) {
1183 			if (gss_auth->target_name == NULL)
1184 				continue;
1185 			if (args->target_name == NULL)
1186 				continue;
1187 			if (strcmp(gss_auth->target_name, args->target_name))
1188 				continue;
1189 		}
1190 		if (!atomic_inc_not_zero(&gss_auth->rpc_auth.au_count))
1191 			continue;
1192 		goto out;
1193 	}
1194 	if (new)
1195 		hash_add(gss_auth_hash_table, &new->hash, hashval);
1196 	gss_auth = new;
1197 out:
1198 	spin_unlock(&gss_auth_hash_lock);
1199 	return gss_auth;
1200 }
1201 
1202 static struct gss_auth *
1203 gss_create_hashed(const struct rpc_auth_create_args *args,
1204 		  struct rpc_clnt *clnt)
1205 {
1206 	struct gss_auth *gss_auth;
1207 	struct gss_auth *new;
1208 
1209 	gss_auth = gss_auth_find_or_add_hashed(args, clnt, NULL);
1210 	if (gss_auth != NULL)
1211 		goto out;
1212 	new = gss_create_new(args, clnt);
1213 	if (IS_ERR(new))
1214 		return new;
1215 	gss_auth = gss_auth_find_or_add_hashed(args, clnt, new);
1216 	if (gss_auth != new)
1217 		gss_destroy(&new->rpc_auth);
1218 out:
1219 	return gss_auth;
1220 }
1221 
1222 static struct rpc_auth *
1223 gss_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1224 {
1225 	struct gss_auth *gss_auth;
1226 	struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
1227 
1228 	while (clnt != clnt->cl_parent) {
1229 		struct rpc_clnt *parent = clnt->cl_parent;
1230 		/* Find the original parent for this transport */
1231 		if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
1232 			break;
1233 		clnt = parent;
1234 	}
1235 
1236 	gss_auth = gss_create_hashed(args, clnt);
1237 	if (IS_ERR(gss_auth))
1238 		return ERR_CAST(gss_auth);
1239 	return &gss_auth->rpc_auth;
1240 }
1241 
1242 /*
1243  * gss_destroying_context will cause the RPCSEC_GSS to send a NULL RPC call
1244  * to the server with the GSS control procedure field set to
1245  * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
1246  * all RPCSEC_GSS state associated with that context.
1247  */
1248 static int
1249 gss_destroying_context(struct rpc_cred *cred)
1250 {
1251 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1252 	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1253 	struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1254 	struct rpc_task *task;
1255 
1256 	if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
1257 		return 0;
1258 
1259 	ctx->gc_proc = RPC_GSS_PROC_DESTROY;
1260 	cred->cr_ops = &gss_nullops;
1261 
1262 	/* Take a reference to ensure the cred will be destroyed either
1263 	 * by the RPC call or by the put_rpccred() below */
1264 	get_rpccred(cred);
1265 
1266 	task = rpc_call_null(gss_auth->client, cred, RPC_TASK_ASYNC|RPC_TASK_SOFT);
1267 	if (!IS_ERR(task))
1268 		rpc_put_task(task);
1269 
1270 	put_rpccred(cred);
1271 	return 1;
1272 }
1273 
1274 /* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
1275  * to create a new cred or context, so they check that things have been
1276  * allocated before freeing them. */
1277 static void
1278 gss_do_free_ctx(struct gss_cl_ctx *ctx)
1279 {
1280 	dprintk("RPC:       %s\n", __func__);
1281 
1282 	gss_delete_sec_context(&ctx->gc_gss_ctx);
1283 	kfree(ctx->gc_wire_ctx.data);
1284 	kfree(ctx->gc_acceptor.data);
1285 	kfree(ctx);
1286 }
1287 
1288 static void
1289 gss_free_ctx_callback(struct rcu_head *head)
1290 {
1291 	struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
1292 	gss_do_free_ctx(ctx);
1293 }
1294 
1295 static void
1296 gss_free_ctx(struct gss_cl_ctx *ctx)
1297 {
1298 	call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
1299 }
1300 
1301 static void
1302 gss_free_cred(struct gss_cred *gss_cred)
1303 {
1304 	dprintk("RPC:       %s cred=%p\n", __func__, gss_cred);
1305 	kfree(gss_cred);
1306 }
1307 
1308 static void
1309 gss_free_cred_callback(struct rcu_head *head)
1310 {
1311 	struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
1312 	gss_free_cred(gss_cred);
1313 }
1314 
1315 static void
1316 gss_destroy_nullcred(struct rpc_cred *cred)
1317 {
1318 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1319 	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1320 	struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1321 
1322 	RCU_INIT_POINTER(gss_cred->gc_ctx, NULL);
1323 	call_rcu(&cred->cr_rcu, gss_free_cred_callback);
1324 	if (ctx)
1325 		gss_put_ctx(ctx);
1326 	gss_put_auth(gss_auth);
1327 }
1328 
1329 static void
1330 gss_destroy_cred(struct rpc_cred *cred)
1331 {
1332 
1333 	if (gss_destroying_context(cred))
1334 		return;
1335 	gss_destroy_nullcred(cred);
1336 }
1337 
1338 static int
1339 gss_hash_cred(struct auth_cred *acred, unsigned int hashbits)
1340 {
1341 	return hash_64(from_kuid(&init_user_ns, acred->uid), hashbits);
1342 }
1343 
1344 /*
1345  * Lookup RPCSEC_GSS cred for the current process
1346  */
1347 static struct rpc_cred *
1348 gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
1349 {
1350 	return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
1351 }
1352 
1353 static struct rpc_cred *
1354 gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
1355 {
1356 	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1357 	struct gss_cred	*cred = NULL;
1358 	int err = -ENOMEM;
1359 
1360 	dprintk("RPC:       %s for uid %d, flavor %d\n",
1361 		__func__, from_kuid(&init_user_ns, acred->uid),
1362 		auth->au_flavor);
1363 
1364 	if (!(cred = kzalloc(sizeof(*cred), gfp)))
1365 		goto out_err;
1366 
1367 	rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
1368 	/*
1369 	 * Note: in order to force a call to call_refresh(), we deliberately
1370 	 * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
1371 	 */
1372 	cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
1373 	cred->gc_service = gss_auth->service;
1374 	cred->gc_principal = NULL;
1375 	if (acred->machine_cred)
1376 		cred->gc_principal = acred->principal;
1377 	kref_get(&gss_auth->kref);
1378 	return &cred->gc_base;
1379 
1380 out_err:
1381 	dprintk("RPC:       %s failed with error %d\n", __func__, err);
1382 	return ERR_PTR(err);
1383 }
1384 
1385 static int
1386 gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
1387 {
1388 	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1389 	struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
1390 	int err;
1391 
1392 	do {
1393 		err = gss_create_upcall(gss_auth, gss_cred);
1394 	} while (err == -EAGAIN);
1395 	return err;
1396 }
1397 
1398 static char *
1399 gss_stringify_acceptor(struct rpc_cred *cred)
1400 {
1401 	char *string = NULL;
1402 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1403 	struct gss_cl_ctx *ctx;
1404 	unsigned int len;
1405 	struct xdr_netobj *acceptor;
1406 
1407 	rcu_read_lock();
1408 	ctx = rcu_dereference(gss_cred->gc_ctx);
1409 	if (!ctx)
1410 		goto out;
1411 
1412 	len = ctx->gc_acceptor.len;
1413 	rcu_read_unlock();
1414 
1415 	/* no point if there's no string */
1416 	if (!len)
1417 		return NULL;
1418 realloc:
1419 	string = kmalloc(len + 1, GFP_KERNEL);
1420 	if (!string)
1421 		return NULL;
1422 
1423 	rcu_read_lock();
1424 	ctx = rcu_dereference(gss_cred->gc_ctx);
1425 
1426 	/* did the ctx disappear or was it replaced by one with no acceptor? */
1427 	if (!ctx || !ctx->gc_acceptor.len) {
1428 		kfree(string);
1429 		string = NULL;
1430 		goto out;
1431 	}
1432 
1433 	acceptor = &ctx->gc_acceptor;
1434 
1435 	/*
1436 	 * Did we find a new acceptor that's longer than the original? Allocate
1437 	 * a longer buffer and try again.
1438 	 */
1439 	if (len < acceptor->len) {
1440 		len = acceptor->len;
1441 		rcu_read_unlock();
1442 		kfree(string);
1443 		goto realloc;
1444 	}
1445 
1446 	memcpy(string, acceptor->data, acceptor->len);
1447 	string[acceptor->len] = '\0';
1448 out:
1449 	rcu_read_unlock();
1450 	return string;
1451 }
1452 
1453 /*
1454  * Returns -EACCES if GSS context is NULL or will expire within the
1455  * timeout (miliseconds)
1456  */
1457 static int
1458 gss_key_timeout(struct rpc_cred *rc)
1459 {
1460 	struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1461 	struct gss_cl_ctx *ctx;
1462 	unsigned long timeout = jiffies + (gss_key_expire_timeo * HZ);
1463 	int ret = 0;
1464 
1465 	rcu_read_lock();
1466 	ctx = rcu_dereference(gss_cred->gc_ctx);
1467 	if (!ctx || time_after(timeout, ctx->gc_expiry))
1468 		ret = -EACCES;
1469 	rcu_read_unlock();
1470 
1471 	return ret;
1472 }
1473 
1474 static int
1475 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
1476 {
1477 	struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1478 	struct gss_cl_ctx *ctx;
1479 	int ret;
1480 
1481 	if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
1482 		goto out;
1483 	/* Don't match with creds that have expired. */
1484 	rcu_read_lock();
1485 	ctx = rcu_dereference(gss_cred->gc_ctx);
1486 	if (!ctx || time_after(jiffies, ctx->gc_expiry)) {
1487 		rcu_read_unlock();
1488 		return 0;
1489 	}
1490 	rcu_read_unlock();
1491 	if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
1492 		return 0;
1493 out:
1494 	if (acred->principal != NULL) {
1495 		if (gss_cred->gc_principal == NULL)
1496 			return 0;
1497 		ret = strcmp(acred->principal, gss_cred->gc_principal) == 0;
1498 		goto check_expire;
1499 	}
1500 	if (gss_cred->gc_principal != NULL)
1501 		return 0;
1502 	ret = uid_eq(rc->cr_uid, acred->uid);
1503 
1504 check_expire:
1505 	if (ret == 0)
1506 		return ret;
1507 
1508 	/* Notify acred users of GSS context expiration timeout */
1509 	if (test_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags) &&
1510 	    (gss_key_timeout(rc) != 0)) {
1511 		/* test will now be done from generic cred */
1512 		test_and_clear_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags);
1513 		/* tell NFS layer that key will expire soon */
1514 		set_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
1515 	}
1516 	return ret;
1517 }
1518 
1519 /*
1520 * Marshal credentials.
1521 * Maybe we should keep a cached credential for performance reasons.
1522 */
1523 static __be32 *
1524 gss_marshal(struct rpc_task *task, __be32 *p)
1525 {
1526 	struct rpc_rqst *req = task->tk_rqstp;
1527 	struct rpc_cred *cred = req->rq_cred;
1528 	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
1529 						 gc_base);
1530 	struct gss_cl_ctx	*ctx = gss_cred_get_ctx(cred);
1531 	__be32		*cred_len;
1532 	u32             maj_stat = 0;
1533 	struct xdr_netobj mic;
1534 	struct kvec	iov;
1535 	struct xdr_buf	verf_buf;
1536 
1537 	dprintk("RPC: %5u %s\n", task->tk_pid, __func__);
1538 
1539 	*p++ = htonl(RPC_AUTH_GSS);
1540 	cred_len = p++;
1541 
1542 	spin_lock(&ctx->gc_seq_lock);
1543 	req->rq_seqno = ctx->gc_seq++;
1544 	spin_unlock(&ctx->gc_seq_lock);
1545 
1546 	*p++ = htonl((u32) RPC_GSS_VERSION);
1547 	*p++ = htonl((u32) ctx->gc_proc);
1548 	*p++ = htonl((u32) req->rq_seqno);
1549 	*p++ = htonl((u32) gss_cred->gc_service);
1550 	p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
1551 	*cred_len = htonl((p - (cred_len + 1)) << 2);
1552 
1553 	/* We compute the checksum for the verifier over the xdr-encoded bytes
1554 	 * starting with the xid and ending at the end of the credential: */
1555 	iov.iov_base = xprt_skip_transport_header(req->rq_xprt,
1556 					req->rq_snd_buf.head[0].iov_base);
1557 	iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
1558 	xdr_buf_from_iov(&iov, &verf_buf);
1559 
1560 	/* set verifier flavor*/
1561 	*p++ = htonl(RPC_AUTH_GSS);
1562 
1563 	mic.data = (u8 *)(p + 1);
1564 	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1565 	if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
1566 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1567 	} else if (maj_stat != 0) {
1568 		printk("gss_marshal: gss_get_mic FAILED (%d)\n", maj_stat);
1569 		goto out_put_ctx;
1570 	}
1571 	p = xdr_encode_opaque(p, NULL, mic.len);
1572 	gss_put_ctx(ctx);
1573 	return p;
1574 out_put_ctx:
1575 	gss_put_ctx(ctx);
1576 	return NULL;
1577 }
1578 
1579 static int gss_renew_cred(struct rpc_task *task)
1580 {
1581 	struct rpc_cred *oldcred = task->tk_rqstp->rq_cred;
1582 	struct gss_cred *gss_cred = container_of(oldcred,
1583 						 struct gss_cred,
1584 						 gc_base);
1585 	struct rpc_auth *auth = oldcred->cr_auth;
1586 	struct auth_cred acred = {
1587 		.uid = oldcred->cr_uid,
1588 		.principal = gss_cred->gc_principal,
1589 		.machine_cred = (gss_cred->gc_principal != NULL ? 1 : 0),
1590 	};
1591 	struct rpc_cred *new;
1592 
1593 	new = gss_lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
1594 	if (IS_ERR(new))
1595 		return PTR_ERR(new);
1596 	task->tk_rqstp->rq_cred = new;
1597 	put_rpccred(oldcred);
1598 	return 0;
1599 }
1600 
1601 static int gss_cred_is_negative_entry(struct rpc_cred *cred)
1602 {
1603 	if (test_bit(RPCAUTH_CRED_NEGATIVE, &cred->cr_flags)) {
1604 		unsigned long now = jiffies;
1605 		unsigned long begin, expire;
1606 		struct gss_cred *gss_cred;
1607 
1608 		gss_cred = container_of(cred, struct gss_cred, gc_base);
1609 		begin = gss_cred->gc_upcall_timestamp;
1610 		expire = begin + gss_expired_cred_retry_delay * HZ;
1611 
1612 		if (time_in_range_open(now, begin, expire))
1613 			return 1;
1614 	}
1615 	return 0;
1616 }
1617 
1618 /*
1619 * Refresh credentials. XXX - finish
1620 */
1621 static int
1622 gss_refresh(struct rpc_task *task)
1623 {
1624 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1625 	int ret = 0;
1626 
1627 	if (gss_cred_is_negative_entry(cred))
1628 		return -EKEYEXPIRED;
1629 
1630 	if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
1631 			!test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags)) {
1632 		ret = gss_renew_cred(task);
1633 		if (ret < 0)
1634 			goto out;
1635 		cred = task->tk_rqstp->rq_cred;
1636 	}
1637 
1638 	if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
1639 		ret = gss_refresh_upcall(task);
1640 out:
1641 	return ret;
1642 }
1643 
1644 /* Dummy refresh routine: used only when destroying the context */
1645 static int
1646 gss_refresh_null(struct rpc_task *task)
1647 {
1648 	return 0;
1649 }
1650 
1651 static __be32 *
1652 gss_validate(struct rpc_task *task, __be32 *p)
1653 {
1654 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1655 	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1656 	__be32		*seq = NULL;
1657 	struct kvec	iov;
1658 	struct xdr_buf	verf_buf;
1659 	struct xdr_netobj mic;
1660 	u32		flav,len;
1661 	u32		maj_stat;
1662 	__be32		*ret = ERR_PTR(-EIO);
1663 
1664 	dprintk("RPC: %5u %s\n", task->tk_pid, __func__);
1665 
1666 	flav = ntohl(*p++);
1667 	if ((len = ntohl(*p++)) > RPC_MAX_AUTH_SIZE)
1668 		goto out_bad;
1669 	if (flav != RPC_AUTH_GSS)
1670 		goto out_bad;
1671 	seq = kmalloc(4, GFP_NOFS);
1672 	if (!seq)
1673 		goto out_bad;
1674 	*seq = htonl(task->tk_rqstp->rq_seqno);
1675 	iov.iov_base = seq;
1676 	iov.iov_len = 4;
1677 	xdr_buf_from_iov(&iov, &verf_buf);
1678 	mic.data = (u8 *)p;
1679 	mic.len = len;
1680 
1681 	ret = ERR_PTR(-EACCES);
1682 	maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1683 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1684 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1685 	if (maj_stat) {
1686 		dprintk("RPC: %5u %s: gss_verify_mic returned error 0x%08x\n",
1687 			task->tk_pid, __func__, maj_stat);
1688 		goto out_bad;
1689 	}
1690 	/* We leave it to unwrap to calculate au_rslack. For now we just
1691 	 * calculate the length of the verifier: */
1692 	cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
1693 	gss_put_ctx(ctx);
1694 	dprintk("RPC: %5u %s: gss_verify_mic succeeded.\n",
1695 			task->tk_pid, __func__);
1696 	kfree(seq);
1697 	return p + XDR_QUADLEN(len);
1698 out_bad:
1699 	gss_put_ctx(ctx);
1700 	dprintk("RPC: %5u %s failed ret %ld.\n", task->tk_pid, __func__,
1701 		PTR_ERR(ret));
1702 	kfree(seq);
1703 	return ret;
1704 }
1705 
1706 static void gss_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
1707 				__be32 *p, void *obj)
1708 {
1709 	struct xdr_stream xdr;
1710 
1711 	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, p);
1712 	encode(rqstp, &xdr, obj);
1713 }
1714 
1715 static inline int
1716 gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1717 		   kxdreproc_t encode, struct rpc_rqst *rqstp,
1718 		   __be32 *p, void *obj)
1719 {
1720 	struct xdr_buf	*snd_buf = &rqstp->rq_snd_buf;
1721 	struct xdr_buf	integ_buf;
1722 	__be32          *integ_len = NULL;
1723 	struct xdr_netobj mic;
1724 	u32		offset;
1725 	__be32		*q;
1726 	struct kvec	*iov;
1727 	u32             maj_stat = 0;
1728 	int		status = -EIO;
1729 
1730 	integ_len = p++;
1731 	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1732 	*p++ = htonl(rqstp->rq_seqno);
1733 
1734 	gss_wrap_req_encode(encode, rqstp, p, obj);
1735 
1736 	if (xdr_buf_subsegment(snd_buf, &integ_buf,
1737 				offset, snd_buf->len - offset))
1738 		return status;
1739 	*integ_len = htonl(integ_buf.len);
1740 
1741 	/* guess whether we're in the head or the tail: */
1742 	if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1743 		iov = snd_buf->tail;
1744 	else
1745 		iov = snd_buf->head;
1746 	p = iov->iov_base + iov->iov_len;
1747 	mic.data = (u8 *)(p + 1);
1748 
1749 	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1750 	status = -EIO; /* XXX? */
1751 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1752 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1753 	else if (maj_stat)
1754 		return status;
1755 	q = xdr_encode_opaque(p, NULL, mic.len);
1756 
1757 	offset = (u8 *)q - (u8 *)p;
1758 	iov->iov_len += offset;
1759 	snd_buf->len += offset;
1760 	return 0;
1761 }
1762 
1763 static void
1764 priv_release_snd_buf(struct rpc_rqst *rqstp)
1765 {
1766 	int i;
1767 
1768 	for (i=0; i < rqstp->rq_enc_pages_num; i++)
1769 		__free_page(rqstp->rq_enc_pages[i]);
1770 	kfree(rqstp->rq_enc_pages);
1771 }
1772 
1773 static int
1774 alloc_enc_pages(struct rpc_rqst *rqstp)
1775 {
1776 	struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
1777 	int first, last, i;
1778 
1779 	if (snd_buf->page_len == 0) {
1780 		rqstp->rq_enc_pages_num = 0;
1781 		return 0;
1782 	}
1783 
1784 	first = snd_buf->page_base >> PAGE_SHIFT;
1785 	last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_SHIFT;
1786 	rqstp->rq_enc_pages_num = last - first + 1 + 1;
1787 	rqstp->rq_enc_pages
1788 		= kmalloc_array(rqstp->rq_enc_pages_num,
1789 				sizeof(struct page *),
1790 				GFP_NOFS);
1791 	if (!rqstp->rq_enc_pages)
1792 		goto out;
1793 	for (i=0; i < rqstp->rq_enc_pages_num; i++) {
1794 		rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
1795 		if (rqstp->rq_enc_pages[i] == NULL)
1796 			goto out_free;
1797 	}
1798 	rqstp->rq_release_snd_buf = priv_release_snd_buf;
1799 	return 0;
1800 out_free:
1801 	rqstp->rq_enc_pages_num = i;
1802 	priv_release_snd_buf(rqstp);
1803 out:
1804 	return -EAGAIN;
1805 }
1806 
1807 static inline int
1808 gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1809 		  kxdreproc_t encode, struct rpc_rqst *rqstp,
1810 		  __be32 *p, void *obj)
1811 {
1812 	struct xdr_buf	*snd_buf = &rqstp->rq_snd_buf;
1813 	u32		offset;
1814 	u32             maj_stat;
1815 	int		status;
1816 	__be32		*opaque_len;
1817 	struct page	**inpages;
1818 	int		first;
1819 	int		pad;
1820 	struct kvec	*iov;
1821 	char		*tmp;
1822 
1823 	opaque_len = p++;
1824 	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1825 	*p++ = htonl(rqstp->rq_seqno);
1826 
1827 	gss_wrap_req_encode(encode, rqstp, p, obj);
1828 
1829 	status = alloc_enc_pages(rqstp);
1830 	if (status)
1831 		return status;
1832 	first = snd_buf->page_base >> PAGE_SHIFT;
1833 	inpages = snd_buf->pages + first;
1834 	snd_buf->pages = rqstp->rq_enc_pages;
1835 	snd_buf->page_base -= first << PAGE_SHIFT;
1836 	/*
1837 	 * Give the tail its own page, in case we need extra space in the
1838 	 * head when wrapping:
1839 	 *
1840 	 * call_allocate() allocates twice the slack space required
1841 	 * by the authentication flavor to rq_callsize.
1842 	 * For GSS, slack is GSS_CRED_SLACK.
1843 	 */
1844 	if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
1845 		tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
1846 		memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
1847 		snd_buf->tail[0].iov_base = tmp;
1848 	}
1849 	maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
1850 	/* slack space should prevent this ever happening: */
1851 	BUG_ON(snd_buf->len > snd_buf->buflen);
1852 	status = -EIO;
1853 	/* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
1854 	 * done anyway, so it's safe to put the request on the wire: */
1855 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1856 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1857 	else if (maj_stat)
1858 		return status;
1859 
1860 	*opaque_len = htonl(snd_buf->len - offset);
1861 	/* guess whether we're in the head or the tail: */
1862 	if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1863 		iov = snd_buf->tail;
1864 	else
1865 		iov = snd_buf->head;
1866 	p = iov->iov_base + iov->iov_len;
1867 	pad = 3 - ((snd_buf->len - offset - 1) & 3);
1868 	memset(p, 0, pad);
1869 	iov->iov_len += pad;
1870 	snd_buf->len += pad;
1871 
1872 	return 0;
1873 }
1874 
1875 static int
1876 gss_wrap_req(struct rpc_task *task,
1877 	     kxdreproc_t encode, void *rqstp, __be32 *p, void *obj)
1878 {
1879 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1880 	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
1881 			gc_base);
1882 	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1883 	int             status = -EIO;
1884 
1885 	dprintk("RPC: %5u %s\n", task->tk_pid, __func__);
1886 	if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
1887 		/* The spec seems a little ambiguous here, but I think that not
1888 		 * wrapping context destruction requests makes the most sense.
1889 		 */
1890 		gss_wrap_req_encode(encode, rqstp, p, obj);
1891 		status = 0;
1892 		goto out;
1893 	}
1894 	switch (gss_cred->gc_service) {
1895 	case RPC_GSS_SVC_NONE:
1896 		gss_wrap_req_encode(encode, rqstp, p, obj);
1897 		status = 0;
1898 		break;
1899 	case RPC_GSS_SVC_INTEGRITY:
1900 		status = gss_wrap_req_integ(cred, ctx, encode, rqstp, p, obj);
1901 		break;
1902 	case RPC_GSS_SVC_PRIVACY:
1903 		status = gss_wrap_req_priv(cred, ctx, encode, rqstp, p, obj);
1904 		break;
1905 	}
1906 out:
1907 	gss_put_ctx(ctx);
1908 	dprintk("RPC: %5u %s returning %d\n", task->tk_pid, __func__, status);
1909 	return status;
1910 }
1911 
1912 static inline int
1913 gss_unwrap_resp_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1914 		struct rpc_rqst *rqstp, __be32 **p)
1915 {
1916 	struct xdr_buf	*rcv_buf = &rqstp->rq_rcv_buf;
1917 	struct xdr_buf integ_buf;
1918 	struct xdr_netobj mic;
1919 	u32 data_offset, mic_offset;
1920 	u32 integ_len;
1921 	u32 maj_stat;
1922 	int status = -EIO;
1923 
1924 	integ_len = ntohl(*(*p)++);
1925 	if (integ_len & 3)
1926 		return status;
1927 	data_offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
1928 	mic_offset = integ_len + data_offset;
1929 	if (mic_offset > rcv_buf->len)
1930 		return status;
1931 	if (ntohl(*(*p)++) != rqstp->rq_seqno)
1932 		return status;
1933 
1934 	if (xdr_buf_subsegment(rcv_buf, &integ_buf, data_offset,
1935 				mic_offset - data_offset))
1936 		return status;
1937 
1938 	if (xdr_buf_read_netobj(rcv_buf, &mic, mic_offset))
1939 		return status;
1940 
1941 	maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1942 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1943 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1944 	if (maj_stat != GSS_S_COMPLETE)
1945 		return status;
1946 	return 0;
1947 }
1948 
1949 static inline int
1950 gss_unwrap_resp_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1951 		struct rpc_rqst *rqstp, __be32 **p)
1952 {
1953 	struct xdr_buf  *rcv_buf = &rqstp->rq_rcv_buf;
1954 	u32 offset;
1955 	u32 opaque_len;
1956 	u32 maj_stat;
1957 	int status = -EIO;
1958 
1959 	opaque_len = ntohl(*(*p)++);
1960 	offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
1961 	if (offset + opaque_len > rcv_buf->len)
1962 		return status;
1963 	/* remove padding: */
1964 	rcv_buf->len = offset + opaque_len;
1965 
1966 	maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
1967 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1968 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1969 	if (maj_stat != GSS_S_COMPLETE)
1970 		return status;
1971 	if (ntohl(*(*p)++) != rqstp->rq_seqno)
1972 		return status;
1973 
1974 	return 0;
1975 }
1976 
1977 static int
1978 gss_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
1979 		      __be32 *p, void *obj)
1980 {
1981 	struct xdr_stream xdr;
1982 
1983 	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
1984 	return decode(rqstp, &xdr, obj);
1985 }
1986 
1987 static int
1988 gss_unwrap_resp(struct rpc_task *task,
1989 		kxdrdproc_t decode, void *rqstp, __be32 *p, void *obj)
1990 {
1991 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1992 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1993 			gc_base);
1994 	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1995 	__be32		*savedp = p;
1996 	struct kvec	*head = ((struct rpc_rqst *)rqstp)->rq_rcv_buf.head;
1997 	int		savedlen = head->iov_len;
1998 	int             status = -EIO;
1999 
2000 	if (ctx->gc_proc != RPC_GSS_PROC_DATA)
2001 		goto out_decode;
2002 	switch (gss_cred->gc_service) {
2003 	case RPC_GSS_SVC_NONE:
2004 		break;
2005 	case RPC_GSS_SVC_INTEGRITY:
2006 		status = gss_unwrap_resp_integ(cred, ctx, rqstp, &p);
2007 		if (status)
2008 			goto out;
2009 		break;
2010 	case RPC_GSS_SVC_PRIVACY:
2011 		status = gss_unwrap_resp_priv(cred, ctx, rqstp, &p);
2012 		if (status)
2013 			goto out;
2014 		break;
2015 	}
2016 	/* take into account extra slack for integrity and privacy cases: */
2017 	cred->cr_auth->au_rslack = cred->cr_auth->au_verfsize + (p - savedp)
2018 						+ (savedlen - head->iov_len);
2019 out_decode:
2020 	status = gss_unwrap_req_decode(decode, rqstp, p, obj);
2021 out:
2022 	gss_put_ctx(ctx);
2023 	dprintk("RPC: %5u %s returning %d\n",
2024 		task->tk_pid, __func__, status);
2025 	return status;
2026 }
2027 
2028 static const struct rpc_authops authgss_ops = {
2029 	.owner		= THIS_MODULE,
2030 	.au_flavor	= RPC_AUTH_GSS,
2031 	.au_name	= "RPCSEC_GSS",
2032 	.create		= gss_create,
2033 	.destroy	= gss_destroy,
2034 	.hash_cred	= gss_hash_cred,
2035 	.lookup_cred	= gss_lookup_cred,
2036 	.crcreate	= gss_create_cred,
2037 	.list_pseudoflavors = gss_mech_list_pseudoflavors,
2038 	.info2flavor	= gss_mech_info2flavor,
2039 	.flavor2info	= gss_mech_flavor2info,
2040 };
2041 
2042 static const struct rpc_credops gss_credops = {
2043 	.cr_name		= "AUTH_GSS",
2044 	.crdestroy		= gss_destroy_cred,
2045 	.cr_init		= gss_cred_init,
2046 	.crbind			= rpcauth_generic_bind_cred,
2047 	.crmatch		= gss_match,
2048 	.crmarshal		= gss_marshal,
2049 	.crrefresh		= gss_refresh,
2050 	.crvalidate		= gss_validate,
2051 	.crwrap_req		= gss_wrap_req,
2052 	.crunwrap_resp		= gss_unwrap_resp,
2053 	.crkey_timeout		= gss_key_timeout,
2054 	.crstringify_acceptor	= gss_stringify_acceptor,
2055 };
2056 
2057 static const struct rpc_credops gss_nullops = {
2058 	.cr_name		= "AUTH_GSS",
2059 	.crdestroy		= gss_destroy_nullcred,
2060 	.crbind			= rpcauth_generic_bind_cred,
2061 	.crmatch		= gss_match,
2062 	.crmarshal		= gss_marshal,
2063 	.crrefresh		= gss_refresh_null,
2064 	.crvalidate		= gss_validate,
2065 	.crwrap_req		= gss_wrap_req,
2066 	.crunwrap_resp		= gss_unwrap_resp,
2067 	.crstringify_acceptor	= gss_stringify_acceptor,
2068 };
2069 
2070 static const struct rpc_pipe_ops gss_upcall_ops_v0 = {
2071 	.upcall		= rpc_pipe_generic_upcall,
2072 	.downcall	= gss_pipe_downcall,
2073 	.destroy_msg	= gss_pipe_destroy_msg,
2074 	.open_pipe	= gss_pipe_open_v0,
2075 	.release_pipe	= gss_pipe_release,
2076 };
2077 
2078 static const struct rpc_pipe_ops gss_upcall_ops_v1 = {
2079 	.upcall		= rpc_pipe_generic_upcall,
2080 	.downcall	= gss_pipe_downcall,
2081 	.destroy_msg	= gss_pipe_destroy_msg,
2082 	.open_pipe	= gss_pipe_open_v1,
2083 	.release_pipe	= gss_pipe_release,
2084 };
2085 
2086 static __net_init int rpcsec_gss_init_net(struct net *net)
2087 {
2088 	return gss_svc_init_net(net);
2089 }
2090 
2091 static __net_exit void rpcsec_gss_exit_net(struct net *net)
2092 {
2093 	gss_svc_shutdown_net(net);
2094 }
2095 
2096 static struct pernet_operations rpcsec_gss_net_ops = {
2097 	.init = rpcsec_gss_init_net,
2098 	.exit = rpcsec_gss_exit_net,
2099 };
2100 
2101 /*
2102  * Initialize RPCSEC_GSS module
2103  */
2104 static int __init init_rpcsec_gss(void)
2105 {
2106 	int err = 0;
2107 
2108 	err = rpcauth_register(&authgss_ops);
2109 	if (err)
2110 		goto out;
2111 	err = gss_svc_init();
2112 	if (err)
2113 		goto out_unregister;
2114 	err = register_pernet_subsys(&rpcsec_gss_net_ops);
2115 	if (err)
2116 		goto out_svc_exit;
2117 	rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
2118 	return 0;
2119 out_svc_exit:
2120 	gss_svc_shutdown();
2121 out_unregister:
2122 	rpcauth_unregister(&authgss_ops);
2123 out:
2124 	return err;
2125 }
2126 
2127 static void __exit exit_rpcsec_gss(void)
2128 {
2129 	unregister_pernet_subsys(&rpcsec_gss_net_ops);
2130 	gss_svc_shutdown();
2131 	rpcauth_unregister(&authgss_ops);
2132 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
2133 }
2134 
2135 MODULE_ALIAS("rpc-auth-6");
2136 MODULE_LICENSE("GPL");
2137 module_param_named(expired_cred_retry_delay,
2138 		   gss_expired_cred_retry_delay,
2139 		   uint, 0644);
2140 MODULE_PARM_DESC(expired_cred_retry_delay, "Timeout (in seconds) until "
2141 		"the RPC engine retries an expired credential");
2142 
2143 module_param_named(key_expire_timeo,
2144 		   gss_key_expire_timeo,
2145 		   uint, 0644);
2146 MODULE_PARM_DESC(key_expire_timeo, "Time (in seconds) at the end of a "
2147 		"credential keys lifetime where the NFS layer cleans up "
2148 		"prior to key expiration");
2149 
2150 module_init(init_rpcsec_gss)
2151 module_exit(exit_rpcsec_gss)
2152