xref: /openbmc/linux/net/sunrpc/auth_gss/auth_gss.c (revision 96de0e252cedffad61b3cb5e05662c591898e69a)
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  * $Id$
38  */
39 
40 
41 #include <linux/module.h>
42 #include <linux/init.h>
43 #include <linux/types.h>
44 #include <linux/slab.h>
45 #include <linux/sched.h>
46 #include <linux/pagemap.h>
47 #include <linux/sunrpc/clnt.h>
48 #include <linux/sunrpc/auth.h>
49 #include <linux/sunrpc/auth_gss.h>
50 #include <linux/sunrpc/svcauth_gss.h>
51 #include <linux/sunrpc/gss_err.h>
52 #include <linux/workqueue.h>
53 #include <linux/sunrpc/rpc_pipe_fs.h>
54 #include <linux/sunrpc/gss_api.h>
55 #include <asm/uaccess.h>
56 
57 static const struct rpc_authops authgss_ops;
58 
59 static const struct rpc_credops gss_credops;
60 static const struct rpc_credops gss_nullops;
61 
62 #ifdef RPC_DEBUG
63 # define RPCDBG_FACILITY	RPCDBG_AUTH
64 #endif
65 
66 #define NFS_NGROUPS	16
67 
68 #define GSS_CRED_SLACK		1024		/* XXX: unused */
69 /* length of a krb5 verifier (48), plus data added before arguments when
70  * using integrity (two 4-byte integers): */
71 #define GSS_VERF_SLACK		100
72 
73 /* XXX this define must match the gssd define
74 * as it is passed to gssd to signal the use of
75 * machine creds should be part of the shared rpc interface */
76 
77 #define CA_RUN_AS_MACHINE  0x00000200
78 
79 /* dump the buffer in `emacs-hexl' style */
80 #define isprint(c)      ((c > 0x1f) && (c < 0x7f))
81 
82 struct gss_auth {
83 	struct kref kref;
84 	struct rpc_auth rpc_auth;
85 	struct gss_api_mech *mech;
86 	enum rpc_gss_svc service;
87 	struct rpc_clnt *client;
88 	struct dentry *dentry;
89 };
90 
91 static void gss_free_ctx(struct gss_cl_ctx *);
92 static struct rpc_pipe_ops gss_upcall_ops;
93 
94 static inline struct gss_cl_ctx *
95 gss_get_ctx(struct gss_cl_ctx *ctx)
96 {
97 	atomic_inc(&ctx->count);
98 	return ctx;
99 }
100 
101 static inline void
102 gss_put_ctx(struct gss_cl_ctx *ctx)
103 {
104 	if (atomic_dec_and_test(&ctx->count))
105 		gss_free_ctx(ctx);
106 }
107 
108 /* gss_cred_set_ctx:
109  * called by gss_upcall_callback and gss_create_upcall in order
110  * to set the gss context. The actual exchange of an old context
111  * and a new one is protected by the inode->i_lock.
112  */
113 static void
114 gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
115 {
116 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
117 	struct gss_cl_ctx *old;
118 
119 	old = gss_cred->gc_ctx;
120 	rcu_assign_pointer(gss_cred->gc_ctx, ctx);
121 	set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
122 	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
123 	if (old)
124 		gss_put_ctx(old);
125 }
126 
127 static int
128 gss_cred_is_uptodate_ctx(struct rpc_cred *cred)
129 {
130 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
131 	int res = 0;
132 
133 	rcu_read_lock();
134 	if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) && gss_cred->gc_ctx)
135 		res = 1;
136 	rcu_read_unlock();
137 	return res;
138 }
139 
140 static const void *
141 simple_get_bytes(const void *p, const void *end, void *res, size_t len)
142 {
143 	const void *q = (const void *)((const char *)p + len);
144 	if (unlikely(q > end || q < p))
145 		return ERR_PTR(-EFAULT);
146 	memcpy(res, p, len);
147 	return q;
148 }
149 
150 static inline const void *
151 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
152 {
153 	const void *q;
154 	unsigned int len;
155 
156 	p = simple_get_bytes(p, end, &len, sizeof(len));
157 	if (IS_ERR(p))
158 		return p;
159 	q = (const void *)((const char *)p + len);
160 	if (unlikely(q > end || q < p))
161 		return ERR_PTR(-EFAULT);
162 	dest->data = kmemdup(p, len, GFP_KERNEL);
163 	if (unlikely(dest->data == NULL))
164 		return ERR_PTR(-ENOMEM);
165 	dest->len = len;
166 	return q;
167 }
168 
169 static struct gss_cl_ctx *
170 gss_cred_get_ctx(struct rpc_cred *cred)
171 {
172 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
173 	struct gss_cl_ctx *ctx = NULL;
174 
175 	rcu_read_lock();
176 	if (gss_cred->gc_ctx)
177 		ctx = gss_get_ctx(gss_cred->gc_ctx);
178 	rcu_read_unlock();
179 	return ctx;
180 }
181 
182 static struct gss_cl_ctx *
183 gss_alloc_context(void)
184 {
185 	struct gss_cl_ctx *ctx;
186 
187 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
188 	if (ctx != NULL) {
189 		ctx->gc_proc = RPC_GSS_PROC_DATA;
190 		ctx->gc_seq = 1;	/* NetApp 6.4R1 doesn't accept seq. no. 0 */
191 		spin_lock_init(&ctx->gc_seq_lock);
192 		atomic_set(&ctx->count,1);
193 	}
194 	return ctx;
195 }
196 
197 #define GSSD_MIN_TIMEOUT (60 * 60)
198 static const void *
199 gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
200 {
201 	const void *q;
202 	unsigned int seclen;
203 	unsigned int timeout;
204 	u32 window_size;
205 	int ret;
206 
207 	/* First unsigned int gives the lifetime (in seconds) of the cred */
208 	p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
209 	if (IS_ERR(p))
210 		goto err;
211 	if (timeout == 0)
212 		timeout = GSSD_MIN_TIMEOUT;
213 	ctx->gc_expiry = jiffies + (unsigned long)timeout * HZ * 3 / 4;
214 	/* Sequence number window. Determines the maximum number of simultaneous requests */
215 	p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
216 	if (IS_ERR(p))
217 		goto err;
218 	ctx->gc_win = window_size;
219 	/* gssd signals an error by passing ctx->gc_win = 0: */
220 	if (ctx->gc_win == 0) {
221 		/* in which case, p points to  an error code which we ignore */
222 		p = ERR_PTR(-EACCES);
223 		goto err;
224 	}
225 	/* copy the opaque wire context */
226 	p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
227 	if (IS_ERR(p))
228 		goto err;
229 	/* import the opaque security context */
230 	p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
231 	if (IS_ERR(p))
232 		goto err;
233 	q = (const void *)((const char *)p + seclen);
234 	if (unlikely(q > end || q < p)) {
235 		p = ERR_PTR(-EFAULT);
236 		goto err;
237 	}
238 	ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx);
239 	if (ret < 0) {
240 		p = ERR_PTR(ret);
241 		goto err;
242 	}
243 	return q;
244 err:
245 	dprintk("RPC:       gss_fill_context returning %ld\n", -PTR_ERR(p));
246 	return p;
247 }
248 
249 
250 struct gss_upcall_msg {
251 	atomic_t count;
252 	uid_t	uid;
253 	struct rpc_pipe_msg msg;
254 	struct list_head list;
255 	struct gss_auth *auth;
256 	struct rpc_wait_queue rpc_waitqueue;
257 	wait_queue_head_t waitqueue;
258 	struct gss_cl_ctx *ctx;
259 };
260 
261 static void
262 gss_release_msg(struct gss_upcall_msg *gss_msg)
263 {
264 	if (!atomic_dec_and_test(&gss_msg->count))
265 		return;
266 	BUG_ON(!list_empty(&gss_msg->list));
267 	if (gss_msg->ctx != NULL)
268 		gss_put_ctx(gss_msg->ctx);
269 	kfree(gss_msg);
270 }
271 
272 static struct gss_upcall_msg *
273 __gss_find_upcall(struct rpc_inode *rpci, uid_t uid)
274 {
275 	struct gss_upcall_msg *pos;
276 	list_for_each_entry(pos, &rpci->in_downcall, list) {
277 		if (pos->uid != uid)
278 			continue;
279 		atomic_inc(&pos->count);
280 		dprintk("RPC:       gss_find_upcall found msg %p\n", pos);
281 		return pos;
282 	}
283 	dprintk("RPC:       gss_find_upcall found nothing\n");
284 	return NULL;
285 }
286 
287 /* Try to add a upcall to the pipefs queue.
288  * If an upcall owned by our uid already exists, then we return a reference
289  * to that upcall instead of adding the new upcall.
290  */
291 static inline struct gss_upcall_msg *
292 gss_add_msg(struct gss_auth *gss_auth, struct gss_upcall_msg *gss_msg)
293 {
294 	struct inode *inode = gss_auth->dentry->d_inode;
295 	struct rpc_inode *rpci = RPC_I(inode);
296 	struct gss_upcall_msg *old;
297 
298 	spin_lock(&inode->i_lock);
299 	old = __gss_find_upcall(rpci, gss_msg->uid);
300 	if (old == NULL) {
301 		atomic_inc(&gss_msg->count);
302 		list_add(&gss_msg->list, &rpci->in_downcall);
303 	} else
304 		gss_msg = old;
305 	spin_unlock(&inode->i_lock);
306 	return gss_msg;
307 }
308 
309 static void
310 __gss_unhash_msg(struct gss_upcall_msg *gss_msg)
311 {
312 	list_del_init(&gss_msg->list);
313 	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
314 	wake_up_all(&gss_msg->waitqueue);
315 	atomic_dec(&gss_msg->count);
316 }
317 
318 static void
319 gss_unhash_msg(struct gss_upcall_msg *gss_msg)
320 {
321 	struct gss_auth *gss_auth = gss_msg->auth;
322 	struct inode *inode = gss_auth->dentry->d_inode;
323 
324 	if (list_empty(&gss_msg->list))
325 		return;
326 	spin_lock(&inode->i_lock);
327 	if (!list_empty(&gss_msg->list))
328 		__gss_unhash_msg(gss_msg);
329 	spin_unlock(&inode->i_lock);
330 }
331 
332 static void
333 gss_upcall_callback(struct rpc_task *task)
334 {
335 	struct gss_cred *gss_cred = container_of(task->tk_msg.rpc_cred,
336 			struct gss_cred, gc_base);
337 	struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
338 	struct inode *inode = gss_msg->auth->dentry->d_inode;
339 
340 	spin_lock(&inode->i_lock);
341 	if (gss_msg->ctx)
342 		gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_get_ctx(gss_msg->ctx));
343 	else
344 		task->tk_status = gss_msg->msg.errno;
345 	gss_cred->gc_upcall = NULL;
346 	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
347 	spin_unlock(&inode->i_lock);
348 	gss_release_msg(gss_msg);
349 }
350 
351 static inline struct gss_upcall_msg *
352 gss_alloc_msg(struct gss_auth *gss_auth, uid_t uid)
353 {
354 	struct gss_upcall_msg *gss_msg;
355 
356 	gss_msg = kzalloc(sizeof(*gss_msg), GFP_KERNEL);
357 	if (gss_msg != NULL) {
358 		INIT_LIST_HEAD(&gss_msg->list);
359 		rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
360 		init_waitqueue_head(&gss_msg->waitqueue);
361 		atomic_set(&gss_msg->count, 1);
362 		gss_msg->msg.data = &gss_msg->uid;
363 		gss_msg->msg.len = sizeof(gss_msg->uid);
364 		gss_msg->uid = uid;
365 		gss_msg->auth = gss_auth;
366 	}
367 	return gss_msg;
368 }
369 
370 static struct gss_upcall_msg *
371 gss_setup_upcall(struct rpc_clnt *clnt, struct gss_auth *gss_auth, struct rpc_cred *cred)
372 {
373 	struct gss_upcall_msg *gss_new, *gss_msg;
374 
375 	gss_new = gss_alloc_msg(gss_auth, cred->cr_uid);
376 	if (gss_new == NULL)
377 		return ERR_PTR(-ENOMEM);
378 	gss_msg = gss_add_msg(gss_auth, gss_new);
379 	if (gss_msg == gss_new) {
380 		int res = rpc_queue_upcall(gss_auth->dentry->d_inode, &gss_new->msg);
381 		if (res) {
382 			gss_unhash_msg(gss_new);
383 			gss_msg = ERR_PTR(res);
384 		}
385 	} else
386 		gss_release_msg(gss_new);
387 	return gss_msg;
388 }
389 
390 static inline int
391 gss_refresh_upcall(struct rpc_task *task)
392 {
393 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
394 	struct gss_auth *gss_auth = container_of(cred->cr_auth,
395 			struct gss_auth, rpc_auth);
396 	struct gss_cred *gss_cred = container_of(cred,
397 			struct gss_cred, gc_base);
398 	struct gss_upcall_msg *gss_msg;
399 	struct inode *inode = gss_auth->dentry->d_inode;
400 	int err = 0;
401 
402 	dprintk("RPC: %5u gss_refresh_upcall for uid %u\n", task->tk_pid,
403 								cred->cr_uid);
404 	gss_msg = gss_setup_upcall(task->tk_client, gss_auth, cred);
405 	if (IS_ERR(gss_msg)) {
406 		err = PTR_ERR(gss_msg);
407 		goto out;
408 	}
409 	spin_lock(&inode->i_lock);
410 	if (gss_cred->gc_upcall != NULL)
411 		rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL, NULL);
412 	else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
413 		task->tk_timeout = 0;
414 		gss_cred->gc_upcall = gss_msg;
415 		/* gss_upcall_callback will release the reference to gss_upcall_msg */
416 		atomic_inc(&gss_msg->count);
417 		rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback, NULL);
418 	} else
419 		err = gss_msg->msg.errno;
420 	spin_unlock(&inode->i_lock);
421 	gss_release_msg(gss_msg);
422 out:
423 	dprintk("RPC: %5u gss_refresh_upcall for uid %u result %d\n",
424 			task->tk_pid, cred->cr_uid, err);
425 	return err;
426 }
427 
428 static inline int
429 gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
430 {
431 	struct inode *inode = gss_auth->dentry->d_inode;
432 	struct rpc_cred *cred = &gss_cred->gc_base;
433 	struct gss_upcall_msg *gss_msg;
434 	DEFINE_WAIT(wait);
435 	int err = 0;
436 
437 	dprintk("RPC:       gss_upcall for uid %u\n", cred->cr_uid);
438 	gss_msg = gss_setup_upcall(gss_auth->client, gss_auth, cred);
439 	if (IS_ERR(gss_msg)) {
440 		err = PTR_ERR(gss_msg);
441 		goto out;
442 	}
443 	for (;;) {
444 		prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_INTERRUPTIBLE);
445 		spin_lock(&inode->i_lock);
446 		if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
447 			break;
448 		}
449 		spin_unlock(&inode->i_lock);
450 		if (signalled()) {
451 			err = -ERESTARTSYS;
452 			goto out_intr;
453 		}
454 		schedule();
455 	}
456 	if (gss_msg->ctx)
457 		gss_cred_set_ctx(cred, gss_get_ctx(gss_msg->ctx));
458 	else
459 		err = gss_msg->msg.errno;
460 	spin_unlock(&inode->i_lock);
461 out_intr:
462 	finish_wait(&gss_msg->waitqueue, &wait);
463 	gss_release_msg(gss_msg);
464 out:
465 	dprintk("RPC:       gss_create_upcall for uid %u result %d\n",
466 			cred->cr_uid, err);
467 	return err;
468 }
469 
470 static ssize_t
471 gss_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
472 		char __user *dst, size_t buflen)
473 {
474 	char *data = (char *)msg->data + msg->copied;
475 	ssize_t mlen = msg->len;
476 	ssize_t left;
477 
478 	if (mlen > buflen)
479 		mlen = buflen;
480 	left = copy_to_user(dst, data, mlen);
481 	if (left < 0) {
482 		msg->errno = left;
483 		return left;
484 	}
485 	mlen -= left;
486 	msg->copied += mlen;
487 	msg->errno = 0;
488 	return mlen;
489 }
490 
491 #define MSG_BUF_MAXSIZE 1024
492 
493 static ssize_t
494 gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
495 {
496 	const void *p, *end;
497 	void *buf;
498 	struct rpc_clnt *clnt;
499 	struct gss_upcall_msg *gss_msg;
500 	struct inode *inode = filp->f_path.dentry->d_inode;
501 	struct gss_cl_ctx *ctx;
502 	uid_t uid;
503 	ssize_t err = -EFBIG;
504 
505 	if (mlen > MSG_BUF_MAXSIZE)
506 		goto out;
507 	err = -ENOMEM;
508 	buf = kmalloc(mlen, GFP_KERNEL);
509 	if (!buf)
510 		goto out;
511 
512 	clnt = RPC_I(inode)->private;
513 	err = -EFAULT;
514 	if (copy_from_user(buf, src, mlen))
515 		goto err;
516 
517 	end = (const void *)((char *)buf + mlen);
518 	p = simple_get_bytes(buf, end, &uid, sizeof(uid));
519 	if (IS_ERR(p)) {
520 		err = PTR_ERR(p);
521 		goto err;
522 	}
523 
524 	err = -ENOMEM;
525 	ctx = gss_alloc_context();
526 	if (ctx == NULL)
527 		goto err;
528 
529 	err = -ENOENT;
530 	/* Find a matching upcall */
531 	spin_lock(&inode->i_lock);
532 	gss_msg = __gss_find_upcall(RPC_I(inode), uid);
533 	if (gss_msg == NULL) {
534 		spin_unlock(&inode->i_lock);
535 		goto err_put_ctx;
536 	}
537 	list_del_init(&gss_msg->list);
538 	spin_unlock(&inode->i_lock);
539 
540 	p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
541 	if (IS_ERR(p)) {
542 		err = PTR_ERR(p);
543 		gss_msg->msg.errno = (err == -EACCES) ? -EACCES : -EAGAIN;
544 		goto err_release_msg;
545 	}
546 	gss_msg->ctx = gss_get_ctx(ctx);
547 	err = mlen;
548 
549 err_release_msg:
550 	spin_lock(&inode->i_lock);
551 	__gss_unhash_msg(gss_msg);
552 	spin_unlock(&inode->i_lock);
553 	gss_release_msg(gss_msg);
554 err_put_ctx:
555 	gss_put_ctx(ctx);
556 err:
557 	kfree(buf);
558 out:
559 	dprintk("RPC:       gss_pipe_downcall returning %Zd\n", err);
560 	return err;
561 }
562 
563 static void
564 gss_pipe_release(struct inode *inode)
565 {
566 	struct rpc_inode *rpci = RPC_I(inode);
567 	struct gss_upcall_msg *gss_msg;
568 
569 	spin_lock(&inode->i_lock);
570 	while (!list_empty(&rpci->in_downcall)) {
571 
572 		gss_msg = list_entry(rpci->in_downcall.next,
573 				struct gss_upcall_msg, list);
574 		gss_msg->msg.errno = -EPIPE;
575 		atomic_inc(&gss_msg->count);
576 		__gss_unhash_msg(gss_msg);
577 		spin_unlock(&inode->i_lock);
578 		gss_release_msg(gss_msg);
579 		spin_lock(&inode->i_lock);
580 	}
581 	spin_unlock(&inode->i_lock);
582 }
583 
584 static void
585 gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
586 {
587 	struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
588 	static unsigned long ratelimit;
589 
590 	if (msg->errno < 0) {
591 		dprintk("RPC:       gss_pipe_destroy_msg releasing msg %p\n",
592 				gss_msg);
593 		atomic_inc(&gss_msg->count);
594 		gss_unhash_msg(gss_msg);
595 		if (msg->errno == -ETIMEDOUT) {
596 			unsigned long now = jiffies;
597 			if (time_after(now, ratelimit)) {
598 				printk(KERN_WARNING "RPC: AUTH_GSS upcall timed out.\n"
599 						    "Please check user daemon is running!\n");
600 				ratelimit = now + 15*HZ;
601 			}
602 		}
603 		gss_release_msg(gss_msg);
604 	}
605 }
606 
607 /*
608  * NOTE: we have the opportunity to use different
609  * parameters based on the input flavor (which must be a pseudoflavor)
610  */
611 static struct rpc_auth *
612 gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
613 {
614 	struct gss_auth *gss_auth;
615 	struct rpc_auth * auth;
616 	int err = -ENOMEM; /* XXX? */
617 
618 	dprintk("RPC:       creating GSS authenticator for client %p\n", clnt);
619 
620 	if (!try_module_get(THIS_MODULE))
621 		return ERR_PTR(err);
622 	if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
623 		goto out_dec;
624 	gss_auth->client = clnt;
625 	err = -EINVAL;
626 	gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
627 	if (!gss_auth->mech) {
628 		printk(KERN_WARNING "%s: Pseudoflavor %d not found!",
629 				__FUNCTION__, flavor);
630 		goto err_free;
631 	}
632 	gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
633 	if (gss_auth->service == 0)
634 		goto err_put_mech;
635 	auth = &gss_auth->rpc_auth;
636 	auth->au_cslack = GSS_CRED_SLACK >> 2;
637 	auth->au_rslack = GSS_VERF_SLACK >> 2;
638 	auth->au_ops = &authgss_ops;
639 	auth->au_flavor = flavor;
640 	atomic_set(&auth->au_count, 1);
641 	kref_init(&gss_auth->kref);
642 
643 	gss_auth->dentry = rpc_mkpipe(clnt->cl_dentry, gss_auth->mech->gm_name,
644 			clnt, &gss_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
645 	if (IS_ERR(gss_auth->dentry)) {
646 		err = PTR_ERR(gss_auth->dentry);
647 		goto err_put_mech;
648 	}
649 
650 	err = rpcauth_init_credcache(auth);
651 	if (err)
652 		goto err_unlink_pipe;
653 
654 	return auth;
655 err_unlink_pipe:
656 	rpc_unlink(gss_auth->dentry);
657 err_put_mech:
658 	gss_mech_put(gss_auth->mech);
659 err_free:
660 	kfree(gss_auth);
661 out_dec:
662 	module_put(THIS_MODULE);
663 	return ERR_PTR(err);
664 }
665 
666 static void
667 gss_free(struct gss_auth *gss_auth)
668 {
669 	rpc_unlink(gss_auth->dentry);
670 	gss_auth->dentry = NULL;
671 	gss_mech_put(gss_auth->mech);
672 
673 	kfree(gss_auth);
674 	module_put(THIS_MODULE);
675 }
676 
677 static void
678 gss_free_callback(struct kref *kref)
679 {
680 	struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
681 
682 	gss_free(gss_auth);
683 }
684 
685 static void
686 gss_destroy(struct rpc_auth *auth)
687 {
688 	struct gss_auth *gss_auth;
689 
690 	dprintk("RPC:       destroying GSS authenticator %p flavor %d\n",
691 			auth, auth->au_flavor);
692 
693 	rpcauth_destroy_credcache(auth);
694 
695 	gss_auth = container_of(auth, struct gss_auth, rpc_auth);
696 	kref_put(&gss_auth->kref, gss_free_callback);
697 }
698 
699 /*
700  * gss_destroying_context will cause the RPCSEC_GSS to send a NULL RPC call
701  * to the server with the GSS control procedure field set to
702  * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
703  * all RPCSEC_GSS state associated with that context.
704  */
705 static int
706 gss_destroying_context(struct rpc_cred *cred)
707 {
708 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
709 	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
710 	struct rpc_task *task;
711 
712 	if (gss_cred->gc_ctx == NULL ||
713 			gss_cred->gc_ctx->gc_proc == RPC_GSS_PROC_DESTROY)
714 		return 0;
715 
716 	gss_cred->gc_ctx->gc_proc = RPC_GSS_PROC_DESTROY;
717 	cred->cr_ops = &gss_nullops;
718 
719 	/* Take a reference to ensure the cred will be destroyed either
720 	 * by the RPC call or by the put_rpccred() below */
721 	get_rpccred(cred);
722 
723 	task = rpc_call_null(gss_auth->client, cred, RPC_TASK_ASYNC);
724 	if (!IS_ERR(task))
725 		rpc_put_task(task);
726 
727 	put_rpccred(cred);
728 	return 1;
729 }
730 
731 /* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
732  * to create a new cred or context, so they check that things have been
733  * allocated before freeing them. */
734 static void
735 gss_do_free_ctx(struct gss_cl_ctx *ctx)
736 {
737 	dprintk("RPC:       gss_free_ctx\n");
738 
739 	kfree(ctx->gc_wire_ctx.data);
740 	kfree(ctx);
741 }
742 
743 static void
744 gss_free_ctx_callback(struct rcu_head *head)
745 {
746 	struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
747 	gss_do_free_ctx(ctx);
748 }
749 
750 static void
751 gss_free_ctx(struct gss_cl_ctx *ctx)
752 {
753 	struct gss_ctx *gc_gss_ctx;
754 
755 	gc_gss_ctx = rcu_dereference(ctx->gc_gss_ctx);
756 	rcu_assign_pointer(ctx->gc_gss_ctx, NULL);
757 	call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
758 	if (gc_gss_ctx)
759 		gss_delete_sec_context(&gc_gss_ctx);
760 }
761 
762 static void
763 gss_free_cred(struct gss_cred *gss_cred)
764 {
765 	dprintk("RPC:       gss_free_cred %p\n", gss_cred);
766 	kfree(gss_cred);
767 }
768 
769 static void
770 gss_free_cred_callback(struct rcu_head *head)
771 {
772 	struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
773 	gss_free_cred(gss_cred);
774 }
775 
776 static void
777 gss_destroy_cred(struct rpc_cred *cred)
778 {
779 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
780 	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
781 	struct gss_cl_ctx *ctx = gss_cred->gc_ctx;
782 
783 	if (gss_destroying_context(cred))
784 		return;
785 	rcu_assign_pointer(gss_cred->gc_ctx, NULL);
786 	call_rcu(&cred->cr_rcu, gss_free_cred_callback);
787 	if (ctx)
788 		gss_put_ctx(ctx);
789 	kref_put(&gss_auth->kref, gss_free_callback);
790 }
791 
792 /*
793  * Lookup RPCSEC_GSS cred for the current process
794  */
795 static struct rpc_cred *
796 gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
797 {
798 	return rpcauth_lookup_credcache(auth, acred, flags);
799 }
800 
801 static struct rpc_cred *
802 gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
803 {
804 	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
805 	struct gss_cred	*cred = NULL;
806 	int err = -ENOMEM;
807 
808 	dprintk("RPC:       gss_create_cred for uid %d, flavor %d\n",
809 		acred->uid, auth->au_flavor);
810 
811 	if (!(cred = kzalloc(sizeof(*cred), GFP_KERNEL)))
812 		goto out_err;
813 
814 	rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
815 	/*
816 	 * Note: in order to force a call to call_refresh(), we deliberately
817 	 * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
818 	 */
819 	cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
820 	cred->gc_service = gss_auth->service;
821 	kref_get(&gss_auth->kref);
822 	return &cred->gc_base;
823 
824 out_err:
825 	dprintk("RPC:       gss_create_cred failed with error %d\n", err);
826 	return ERR_PTR(err);
827 }
828 
829 static int
830 gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
831 {
832 	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
833 	struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
834 	int err;
835 
836 	do {
837 		err = gss_create_upcall(gss_auth, gss_cred);
838 	} while (err == -EAGAIN);
839 	return err;
840 }
841 
842 static int
843 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
844 {
845 	struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
846 
847 	/*
848 	 * If the searchflags have set RPCAUTH_LOOKUP_NEW, then
849 	 * we don't really care if the credential has expired or not,
850 	 * since the caller should be prepared to reinitialise it.
851 	 */
852 	if ((flags & RPCAUTH_LOOKUP_NEW) && test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
853 		goto out;
854 	/* Don't match with creds that have expired. */
855 	if (gss_cred->gc_ctx && time_after(jiffies, gss_cred->gc_ctx->gc_expiry))
856 		return 0;
857 out:
858 	return (rc->cr_uid == acred->uid);
859 }
860 
861 /*
862 * Marshal credentials.
863 * Maybe we should keep a cached credential for performance reasons.
864 */
865 static __be32 *
866 gss_marshal(struct rpc_task *task, __be32 *p)
867 {
868 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
869 	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
870 						 gc_base);
871 	struct gss_cl_ctx	*ctx = gss_cred_get_ctx(cred);
872 	__be32		*cred_len;
873 	struct rpc_rqst *req = task->tk_rqstp;
874 	u32             maj_stat = 0;
875 	struct xdr_netobj mic;
876 	struct kvec	iov;
877 	struct xdr_buf	verf_buf;
878 
879 	dprintk("RPC: %5u gss_marshal\n", task->tk_pid);
880 
881 	*p++ = htonl(RPC_AUTH_GSS);
882 	cred_len = p++;
883 
884 	spin_lock(&ctx->gc_seq_lock);
885 	req->rq_seqno = ctx->gc_seq++;
886 	spin_unlock(&ctx->gc_seq_lock);
887 
888 	*p++ = htonl((u32) RPC_GSS_VERSION);
889 	*p++ = htonl((u32) ctx->gc_proc);
890 	*p++ = htonl((u32) req->rq_seqno);
891 	*p++ = htonl((u32) gss_cred->gc_service);
892 	p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
893 	*cred_len = htonl((p - (cred_len + 1)) << 2);
894 
895 	/* We compute the checksum for the verifier over the xdr-encoded bytes
896 	 * starting with the xid and ending at the end of the credential: */
897 	iov.iov_base = xprt_skip_transport_header(task->tk_xprt,
898 					req->rq_snd_buf.head[0].iov_base);
899 	iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
900 	xdr_buf_from_iov(&iov, &verf_buf);
901 
902 	/* set verifier flavor*/
903 	*p++ = htonl(RPC_AUTH_GSS);
904 
905 	mic.data = (u8 *)(p + 1);
906 	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
907 	if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
908 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
909 	} else if (maj_stat != 0) {
910 		printk("gss_marshal: gss_get_mic FAILED (%d)\n", maj_stat);
911 		goto out_put_ctx;
912 	}
913 	p = xdr_encode_opaque(p, NULL, mic.len);
914 	gss_put_ctx(ctx);
915 	return p;
916 out_put_ctx:
917 	gss_put_ctx(ctx);
918 	return NULL;
919 }
920 
921 /*
922 * Refresh credentials. XXX - finish
923 */
924 static int
925 gss_refresh(struct rpc_task *task)
926 {
927 
928 	if (!gss_cred_is_uptodate_ctx(task->tk_msg.rpc_cred))
929 		return gss_refresh_upcall(task);
930 	return 0;
931 }
932 
933 /* Dummy refresh routine: used only when destroying the context */
934 static int
935 gss_refresh_null(struct rpc_task *task)
936 {
937 	return -EACCES;
938 }
939 
940 static __be32 *
941 gss_validate(struct rpc_task *task, __be32 *p)
942 {
943 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
944 	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
945 	__be32		seq;
946 	struct kvec	iov;
947 	struct xdr_buf	verf_buf;
948 	struct xdr_netobj mic;
949 	u32		flav,len;
950 	u32		maj_stat;
951 
952 	dprintk("RPC: %5u gss_validate\n", task->tk_pid);
953 
954 	flav = ntohl(*p++);
955 	if ((len = ntohl(*p++)) > RPC_MAX_AUTH_SIZE)
956 		goto out_bad;
957 	if (flav != RPC_AUTH_GSS)
958 		goto out_bad;
959 	seq = htonl(task->tk_rqstp->rq_seqno);
960 	iov.iov_base = &seq;
961 	iov.iov_len = sizeof(seq);
962 	xdr_buf_from_iov(&iov, &verf_buf);
963 	mic.data = (u8 *)p;
964 	mic.len = len;
965 
966 	maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
967 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
968 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
969 	if (maj_stat) {
970 		dprintk("RPC: %5u gss_validate: gss_verify_mic returned"
971 				"error 0x%08x\n", task->tk_pid, maj_stat);
972 		goto out_bad;
973 	}
974 	/* We leave it to unwrap to calculate au_rslack. For now we just
975 	 * calculate the length of the verifier: */
976 	cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
977 	gss_put_ctx(ctx);
978 	dprintk("RPC: %5u gss_validate: gss_verify_mic succeeded.\n",
979 			task->tk_pid);
980 	return p + XDR_QUADLEN(len);
981 out_bad:
982 	gss_put_ctx(ctx);
983 	dprintk("RPC: %5u gss_validate failed.\n", task->tk_pid);
984 	return NULL;
985 }
986 
987 static inline int
988 gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
989 		kxdrproc_t encode, struct rpc_rqst *rqstp, __be32 *p, void *obj)
990 {
991 	struct xdr_buf	*snd_buf = &rqstp->rq_snd_buf;
992 	struct xdr_buf	integ_buf;
993 	__be32          *integ_len = NULL;
994 	struct xdr_netobj mic;
995 	u32		offset;
996 	__be32		*q;
997 	struct kvec	*iov;
998 	u32             maj_stat = 0;
999 	int		status = -EIO;
1000 
1001 	integ_len = p++;
1002 	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1003 	*p++ = htonl(rqstp->rq_seqno);
1004 
1005 	status = rpc_call_xdrproc(encode, rqstp, p, obj);
1006 	if (status)
1007 		return status;
1008 
1009 	if (xdr_buf_subsegment(snd_buf, &integ_buf,
1010 				offset, snd_buf->len - offset))
1011 		return status;
1012 	*integ_len = htonl(integ_buf.len);
1013 
1014 	/* guess whether we're in the head or the tail: */
1015 	if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1016 		iov = snd_buf->tail;
1017 	else
1018 		iov = snd_buf->head;
1019 	p = iov->iov_base + iov->iov_len;
1020 	mic.data = (u8 *)(p + 1);
1021 
1022 	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1023 	status = -EIO; /* XXX? */
1024 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1025 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1026 	else if (maj_stat)
1027 		return status;
1028 	q = xdr_encode_opaque(p, NULL, mic.len);
1029 
1030 	offset = (u8 *)q - (u8 *)p;
1031 	iov->iov_len += offset;
1032 	snd_buf->len += offset;
1033 	return 0;
1034 }
1035 
1036 static void
1037 priv_release_snd_buf(struct rpc_rqst *rqstp)
1038 {
1039 	int i;
1040 
1041 	for (i=0; i < rqstp->rq_enc_pages_num; i++)
1042 		__free_page(rqstp->rq_enc_pages[i]);
1043 	kfree(rqstp->rq_enc_pages);
1044 }
1045 
1046 static int
1047 alloc_enc_pages(struct rpc_rqst *rqstp)
1048 {
1049 	struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
1050 	int first, last, i;
1051 
1052 	if (snd_buf->page_len == 0) {
1053 		rqstp->rq_enc_pages_num = 0;
1054 		return 0;
1055 	}
1056 
1057 	first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
1058 	last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_CACHE_SHIFT;
1059 	rqstp->rq_enc_pages_num = last - first + 1 + 1;
1060 	rqstp->rq_enc_pages
1061 		= kmalloc(rqstp->rq_enc_pages_num * sizeof(struct page *),
1062 				GFP_NOFS);
1063 	if (!rqstp->rq_enc_pages)
1064 		goto out;
1065 	for (i=0; i < rqstp->rq_enc_pages_num; i++) {
1066 		rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
1067 		if (rqstp->rq_enc_pages[i] == NULL)
1068 			goto out_free;
1069 	}
1070 	rqstp->rq_release_snd_buf = priv_release_snd_buf;
1071 	return 0;
1072 out_free:
1073 	for (i--; i >= 0; i--) {
1074 		__free_page(rqstp->rq_enc_pages[i]);
1075 	}
1076 out:
1077 	return -EAGAIN;
1078 }
1079 
1080 static inline int
1081 gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1082 		kxdrproc_t encode, struct rpc_rqst *rqstp, __be32 *p, void *obj)
1083 {
1084 	struct xdr_buf	*snd_buf = &rqstp->rq_snd_buf;
1085 	u32		offset;
1086 	u32             maj_stat;
1087 	int		status;
1088 	__be32		*opaque_len;
1089 	struct page	**inpages;
1090 	int		first;
1091 	int		pad;
1092 	struct kvec	*iov;
1093 	char		*tmp;
1094 
1095 	opaque_len = p++;
1096 	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1097 	*p++ = htonl(rqstp->rq_seqno);
1098 
1099 	status = rpc_call_xdrproc(encode, rqstp, p, obj);
1100 	if (status)
1101 		return status;
1102 
1103 	status = alloc_enc_pages(rqstp);
1104 	if (status)
1105 		return status;
1106 	first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
1107 	inpages = snd_buf->pages + first;
1108 	snd_buf->pages = rqstp->rq_enc_pages;
1109 	snd_buf->page_base -= first << PAGE_CACHE_SHIFT;
1110 	/* Give the tail its own page, in case we need extra space in the
1111 	 * head when wrapping: */
1112 	if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
1113 		tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
1114 		memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
1115 		snd_buf->tail[0].iov_base = tmp;
1116 	}
1117 	maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
1118 	/* RPC_SLACK_SPACE should prevent this ever happening: */
1119 	BUG_ON(snd_buf->len > snd_buf->buflen);
1120 	status = -EIO;
1121 	/* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
1122 	 * done anyway, so it's safe to put the request on the wire: */
1123 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1124 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1125 	else if (maj_stat)
1126 		return status;
1127 
1128 	*opaque_len = htonl(snd_buf->len - offset);
1129 	/* guess whether we're in the head or the tail: */
1130 	if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1131 		iov = snd_buf->tail;
1132 	else
1133 		iov = snd_buf->head;
1134 	p = iov->iov_base + iov->iov_len;
1135 	pad = 3 - ((snd_buf->len - offset - 1) & 3);
1136 	memset(p, 0, pad);
1137 	iov->iov_len += pad;
1138 	snd_buf->len += pad;
1139 
1140 	return 0;
1141 }
1142 
1143 static int
1144 gss_wrap_req(struct rpc_task *task,
1145 	     kxdrproc_t encode, void *rqstp, __be32 *p, void *obj)
1146 {
1147 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
1148 	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
1149 			gc_base);
1150 	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1151 	int             status = -EIO;
1152 
1153 	dprintk("RPC: %5u gss_wrap_req\n", task->tk_pid);
1154 	if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
1155 		/* The spec seems a little ambiguous here, but I think that not
1156 		 * wrapping context destruction requests makes the most sense.
1157 		 */
1158 		status = rpc_call_xdrproc(encode, rqstp, p, obj);
1159 		goto out;
1160 	}
1161 	switch (gss_cred->gc_service) {
1162 		case RPC_GSS_SVC_NONE:
1163 			status = rpc_call_xdrproc(encode, rqstp, p, obj);
1164 			break;
1165 		case RPC_GSS_SVC_INTEGRITY:
1166 			status = gss_wrap_req_integ(cred, ctx, encode,
1167 								rqstp, p, obj);
1168 			break;
1169 		case RPC_GSS_SVC_PRIVACY:
1170 			status = gss_wrap_req_priv(cred, ctx, encode,
1171 					rqstp, p, obj);
1172 			break;
1173 	}
1174 out:
1175 	gss_put_ctx(ctx);
1176 	dprintk("RPC: %5u gss_wrap_req returning %d\n", task->tk_pid, status);
1177 	return status;
1178 }
1179 
1180 static inline int
1181 gss_unwrap_resp_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1182 		struct rpc_rqst *rqstp, __be32 **p)
1183 {
1184 	struct xdr_buf	*rcv_buf = &rqstp->rq_rcv_buf;
1185 	struct xdr_buf integ_buf;
1186 	struct xdr_netobj mic;
1187 	u32 data_offset, mic_offset;
1188 	u32 integ_len;
1189 	u32 maj_stat;
1190 	int status = -EIO;
1191 
1192 	integ_len = ntohl(*(*p)++);
1193 	if (integ_len & 3)
1194 		return status;
1195 	data_offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
1196 	mic_offset = integ_len + data_offset;
1197 	if (mic_offset > rcv_buf->len)
1198 		return status;
1199 	if (ntohl(*(*p)++) != rqstp->rq_seqno)
1200 		return status;
1201 
1202 	if (xdr_buf_subsegment(rcv_buf, &integ_buf, data_offset,
1203 				mic_offset - data_offset))
1204 		return status;
1205 
1206 	if (xdr_buf_read_netobj(rcv_buf, &mic, mic_offset))
1207 		return status;
1208 
1209 	maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1210 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1211 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1212 	if (maj_stat != GSS_S_COMPLETE)
1213 		return status;
1214 	return 0;
1215 }
1216 
1217 static inline int
1218 gss_unwrap_resp_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1219 		struct rpc_rqst *rqstp, __be32 **p)
1220 {
1221 	struct xdr_buf  *rcv_buf = &rqstp->rq_rcv_buf;
1222 	u32 offset;
1223 	u32 opaque_len;
1224 	u32 maj_stat;
1225 	int status = -EIO;
1226 
1227 	opaque_len = ntohl(*(*p)++);
1228 	offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
1229 	if (offset + opaque_len > rcv_buf->len)
1230 		return status;
1231 	/* remove padding: */
1232 	rcv_buf->len = offset + opaque_len;
1233 
1234 	maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
1235 	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1236 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1237 	if (maj_stat != GSS_S_COMPLETE)
1238 		return status;
1239 	if (ntohl(*(*p)++) != rqstp->rq_seqno)
1240 		return status;
1241 
1242 	return 0;
1243 }
1244 
1245 
1246 static int
1247 gss_unwrap_resp(struct rpc_task *task,
1248 		kxdrproc_t decode, void *rqstp, __be32 *p, void *obj)
1249 {
1250 	struct rpc_cred *cred = task->tk_msg.rpc_cred;
1251 	struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1252 			gc_base);
1253 	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1254 	__be32		*savedp = p;
1255 	struct kvec	*head = ((struct rpc_rqst *)rqstp)->rq_rcv_buf.head;
1256 	int		savedlen = head->iov_len;
1257 	int             status = -EIO;
1258 
1259 	if (ctx->gc_proc != RPC_GSS_PROC_DATA)
1260 		goto out_decode;
1261 	switch (gss_cred->gc_service) {
1262 		case RPC_GSS_SVC_NONE:
1263 			break;
1264 		case RPC_GSS_SVC_INTEGRITY:
1265 			status = gss_unwrap_resp_integ(cred, ctx, rqstp, &p);
1266 			if (status)
1267 				goto out;
1268 			break;
1269 		case RPC_GSS_SVC_PRIVACY:
1270 			status = gss_unwrap_resp_priv(cred, ctx, rqstp, &p);
1271 			if (status)
1272 				goto out;
1273 			break;
1274 	}
1275 	/* take into account extra slack for integrity and privacy cases: */
1276 	cred->cr_auth->au_rslack = cred->cr_auth->au_verfsize + (p - savedp)
1277 						+ (savedlen - head->iov_len);
1278 out_decode:
1279 	status = rpc_call_xdrproc(decode, rqstp, p, obj);
1280 out:
1281 	gss_put_ctx(ctx);
1282 	dprintk("RPC: %5u gss_unwrap_resp returning %d\n", task->tk_pid,
1283 			status);
1284 	return status;
1285 }
1286 
1287 static const struct rpc_authops authgss_ops = {
1288 	.owner		= THIS_MODULE,
1289 	.au_flavor	= RPC_AUTH_GSS,
1290 #ifdef RPC_DEBUG
1291 	.au_name	= "RPCSEC_GSS",
1292 #endif
1293 	.create		= gss_create,
1294 	.destroy	= gss_destroy,
1295 	.lookup_cred	= gss_lookup_cred,
1296 	.crcreate	= gss_create_cred
1297 };
1298 
1299 static const struct rpc_credops gss_credops = {
1300 	.cr_name	= "AUTH_GSS",
1301 	.crdestroy	= gss_destroy_cred,
1302 	.cr_init	= gss_cred_init,
1303 	.crmatch	= gss_match,
1304 	.crmarshal	= gss_marshal,
1305 	.crrefresh	= gss_refresh,
1306 	.crvalidate	= gss_validate,
1307 	.crwrap_req	= gss_wrap_req,
1308 	.crunwrap_resp	= gss_unwrap_resp,
1309 };
1310 
1311 static const struct rpc_credops gss_nullops = {
1312 	.cr_name	= "AUTH_GSS",
1313 	.crdestroy	= gss_destroy_cred,
1314 	.crmatch	= gss_match,
1315 	.crmarshal	= gss_marshal,
1316 	.crrefresh	= gss_refresh_null,
1317 	.crvalidate	= gss_validate,
1318 	.crwrap_req	= gss_wrap_req,
1319 	.crunwrap_resp	= gss_unwrap_resp,
1320 };
1321 
1322 static struct rpc_pipe_ops gss_upcall_ops = {
1323 	.upcall		= gss_pipe_upcall,
1324 	.downcall	= gss_pipe_downcall,
1325 	.destroy_msg	= gss_pipe_destroy_msg,
1326 	.release_pipe	= gss_pipe_release,
1327 };
1328 
1329 /*
1330  * Initialize RPCSEC_GSS module
1331  */
1332 static int __init init_rpcsec_gss(void)
1333 {
1334 	int err = 0;
1335 
1336 	err = rpcauth_register(&authgss_ops);
1337 	if (err)
1338 		goto out;
1339 	err = gss_svc_init();
1340 	if (err)
1341 		goto out_unregister;
1342 	return 0;
1343 out_unregister:
1344 	rpcauth_unregister(&authgss_ops);
1345 out:
1346 	return err;
1347 }
1348 
1349 static void __exit exit_rpcsec_gss(void)
1350 {
1351 	gss_svc_shutdown();
1352 	rpcauth_unregister(&authgss_ops);
1353 }
1354 
1355 MODULE_LICENSE("GPL");
1356 module_init(init_rpcsec_gss)
1357 module_exit(exit_rpcsec_gss)
1358