xref: /openbmc/linux/net/rxrpc/key.c (revision 5d0e4d78) 
1 /* RxRPC key management
2  *
3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  *
11  * RxRPC keys should have a description of describing their purpose:
12  *	"afs@CAMBRIDGE.REDHAT.COM>
13  */
14 
15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 
17 #include <crypto/skcipher.h>
18 #include <linux/module.h>
19 #include <linux/net.h>
20 #include <linux/skbuff.h>
21 #include <linux/key-type.h>
22 #include <linux/ctype.h>
23 #include <linux/slab.h>
24 #include <net/sock.h>
25 #include <net/af_rxrpc.h>
26 #include <keys/rxrpc-type.h>
27 #include <keys/user-type.h>
28 #include "ar-internal.h"
29 
30 static int rxrpc_vet_description_s(const char *);
31 static int rxrpc_preparse(struct key_preparsed_payload *);
32 static int rxrpc_preparse_s(struct key_preparsed_payload *);
33 static void rxrpc_free_preparse(struct key_preparsed_payload *);
34 static void rxrpc_free_preparse_s(struct key_preparsed_payload *);
35 static void rxrpc_destroy(struct key *);
36 static void rxrpc_destroy_s(struct key *);
37 static void rxrpc_describe(const struct key *, struct seq_file *);
38 static long rxrpc_read(const struct key *, char __user *, size_t);
39 
40 /*
41  * rxrpc defined keys take an arbitrary string as the description and an
42  * arbitrary blob of data as the payload
43  */
44 struct key_type key_type_rxrpc = {
45 	.name		= "rxrpc",
46 	.preparse	= rxrpc_preparse,
47 	.free_preparse	= rxrpc_free_preparse,
48 	.instantiate	= generic_key_instantiate,
49 	.destroy	= rxrpc_destroy,
50 	.describe	= rxrpc_describe,
51 	.read		= rxrpc_read,
52 };
53 EXPORT_SYMBOL(key_type_rxrpc);
54 
55 /*
56  * rxrpc server defined keys take "<serviceId>:<securityIndex>" as the
57  * description and an 8-byte decryption key as the payload
58  */
59 struct key_type key_type_rxrpc_s = {
60 	.name		= "rxrpc_s",
61 	.vet_description = rxrpc_vet_description_s,
62 	.preparse	= rxrpc_preparse_s,
63 	.free_preparse	= rxrpc_free_preparse_s,
64 	.instantiate	= generic_key_instantiate,
65 	.destroy	= rxrpc_destroy_s,
66 	.describe	= rxrpc_describe,
67 };
68 
69 /*
70  * Vet the description for an RxRPC server key
71  */
72 static int rxrpc_vet_description_s(const char *desc)
73 {
74 	unsigned long num;
75 	char *p;
76 
77 	num = simple_strtoul(desc, &p, 10);
78 	if (*p != ':' || num > 65535)
79 		return -EINVAL;
80 	num = simple_strtoul(p + 1, &p, 10);
81 	if (*p || num < 1 || num > 255)
82 		return -EINVAL;
83 	return 0;
84 }
85 
86 /*
87  * parse an RxKAD type XDR format token
88  * - the caller guarantees we have at least 4 words
89  */
90 static int rxrpc_preparse_xdr_rxkad(struct key_preparsed_payload *prep,
91 				    size_t datalen,
92 				    const __be32 *xdr, unsigned int toklen)
93 {
94 	struct rxrpc_key_token *token, **pptoken;
95 	size_t plen;
96 	u32 tktlen;
97 
98 	_enter(",{%x,%x,%x,%x},%u",
99 	       ntohl(xdr[0]), ntohl(xdr[1]), ntohl(xdr[2]), ntohl(xdr[3]),
100 	       toklen);
101 
102 	if (toklen <= 8 * 4)
103 		return -EKEYREJECTED;
104 	tktlen = ntohl(xdr[7]);
105 	_debug("tktlen: %x", tktlen);
106 	if (tktlen > AFSTOKEN_RK_TIX_MAX)
107 		return -EKEYREJECTED;
108 	if (toklen < 8 * 4 + tktlen)
109 		return -EKEYREJECTED;
110 
111 	plen = sizeof(*token) + sizeof(*token->kad) + tktlen;
112 	prep->quotalen = datalen + plen;
113 
114 	plen -= sizeof(*token);
115 	token = kzalloc(sizeof(*token), GFP_KERNEL);
116 	if (!token)
117 		return -ENOMEM;
118 
119 	token->kad = kzalloc(plen, GFP_KERNEL);
120 	if (!token->kad) {
121 		kfree(token);
122 		return -ENOMEM;
123 	}
124 
125 	token->security_index	= RXRPC_SECURITY_RXKAD;
126 	token->kad->ticket_len	= tktlen;
127 	token->kad->vice_id	= ntohl(xdr[0]);
128 	token->kad->kvno	= ntohl(xdr[1]);
129 	token->kad->start	= ntohl(xdr[4]);
130 	token->kad->expiry	= ntohl(xdr[5]);
131 	token->kad->primary_flag = ntohl(xdr[6]);
132 	memcpy(&token->kad->session_key, &xdr[2], 8);
133 	memcpy(&token->kad->ticket, &xdr[8], tktlen);
134 
135 	_debug("SCIX: %u", token->security_index);
136 	_debug("TLEN: %u", token->kad->ticket_len);
137 	_debug("EXPY: %x", token->kad->expiry);
138 	_debug("KVNO: %u", token->kad->kvno);
139 	_debug("PRIM: %u", token->kad->primary_flag);
140 	_debug("SKEY: %02x%02x%02x%02x%02x%02x%02x%02x",
141 	       token->kad->session_key[0], token->kad->session_key[1],
142 	       token->kad->session_key[2], token->kad->session_key[3],
143 	       token->kad->session_key[4], token->kad->session_key[5],
144 	       token->kad->session_key[6], token->kad->session_key[7]);
145 	if (token->kad->ticket_len >= 8)
146 		_debug("TCKT: %02x%02x%02x%02x%02x%02x%02x%02x",
147 		       token->kad->ticket[0], token->kad->ticket[1],
148 		       token->kad->ticket[2], token->kad->ticket[3],
149 		       token->kad->ticket[4], token->kad->ticket[5],
150 		       token->kad->ticket[6], token->kad->ticket[7]);
151 
152 	/* count the number of tokens attached */
153 	prep->payload.data[1] = (void *)((unsigned long)prep->payload.data[1] + 1);
154 
155 	/* attach the data */
156 	for (pptoken = (struct rxrpc_key_token **)&prep->payload.data[0];
157 	     *pptoken;
158 	     pptoken = &(*pptoken)->next)
159 		continue;
160 	*pptoken = token;
161 	if (token->kad->expiry < prep->expiry)
162 		prep->expiry = token->kad->expiry;
163 
164 	_leave(" = 0");
165 	return 0;
166 }
167 
168 static void rxrpc_free_krb5_principal(struct krb5_principal *princ)
169 {
170 	int loop;
171 
172 	if (princ->name_parts) {
173 		for (loop = princ->n_name_parts - 1; loop >= 0; loop--)
174 			kfree(princ->name_parts[loop]);
175 		kfree(princ->name_parts);
176 	}
177 	kfree(princ->realm);
178 }
179 
180 static void rxrpc_free_krb5_tagged(struct krb5_tagged_data *td)
181 {
182 	kfree(td->data);
183 }
184 
185 /*
186  * free up an RxK5 token
187  */
188 static void rxrpc_rxk5_free(struct rxk5_key *rxk5)
189 {
190 	int loop;
191 
192 	rxrpc_free_krb5_principal(&rxk5->client);
193 	rxrpc_free_krb5_principal(&rxk5->server);
194 	rxrpc_free_krb5_tagged(&rxk5->session);
195 
196 	if (rxk5->addresses) {
197 		for (loop = rxk5->n_addresses - 1; loop >= 0; loop--)
198 			rxrpc_free_krb5_tagged(&rxk5->addresses[loop]);
199 		kfree(rxk5->addresses);
200 	}
201 	if (rxk5->authdata) {
202 		for (loop = rxk5->n_authdata - 1; loop >= 0; loop--)
203 			rxrpc_free_krb5_tagged(&rxk5->authdata[loop]);
204 		kfree(rxk5->authdata);
205 	}
206 
207 	kfree(rxk5->ticket);
208 	kfree(rxk5->ticket2);
209 	kfree(rxk5);
210 }
211 
212 /*
213  * extract a krb5 principal
214  */
215 static int rxrpc_krb5_decode_principal(struct krb5_principal *princ,
216 				       const __be32 **_xdr,
217 				       unsigned int *_toklen)
218 {
219 	const __be32 *xdr = *_xdr;
220 	unsigned int toklen = *_toklen, n_parts, loop, tmp, paddedlen;
221 
222 	/* there must be at least one name, and at least #names+1 length
223 	 * words */
224 	if (toklen <= 12)
225 		return -EINVAL;
226 
227 	_enter(",{%x,%x,%x},%u",
228 	       ntohl(xdr[0]), ntohl(xdr[1]), ntohl(xdr[2]), toklen);
229 
230 	n_parts = ntohl(*xdr++);
231 	toklen -= 4;
232 	if (n_parts <= 0 || n_parts > AFSTOKEN_K5_COMPONENTS_MAX)
233 		return -EINVAL;
234 	princ->n_name_parts = n_parts;
235 
236 	if (toklen <= (n_parts + 1) * 4)
237 		return -EINVAL;
238 
239 	princ->name_parts = kcalloc(n_parts, sizeof(char *), GFP_KERNEL);
240 	if (!princ->name_parts)
241 		return -ENOMEM;
242 
243 	for (loop = 0; loop < n_parts; loop++) {
244 		if (toklen < 4)
245 			return -EINVAL;
246 		tmp = ntohl(*xdr++);
247 		toklen -= 4;
248 		if (tmp <= 0 || tmp > AFSTOKEN_STRING_MAX)
249 			return -EINVAL;
250 		paddedlen = (tmp + 3) & ~3;
251 		if (paddedlen > toklen)
252 			return -EINVAL;
253 		princ->name_parts[loop] = kmalloc(tmp + 1, GFP_KERNEL);
254 		if (!princ->name_parts[loop])
255 			return -ENOMEM;
256 		memcpy(princ->name_parts[loop], xdr, tmp);
257 		princ->name_parts[loop][tmp] = 0;
258 		toklen -= paddedlen;
259 		xdr += paddedlen >> 2;
260 	}
261 
262 	if (toklen < 4)
263 		return -EINVAL;
264 	tmp = ntohl(*xdr++);
265 	toklen -= 4;
266 	if (tmp <= 0 || tmp > AFSTOKEN_K5_REALM_MAX)
267 		return -EINVAL;
268 	paddedlen = (tmp + 3) & ~3;
269 	if (paddedlen > toklen)
270 		return -EINVAL;
271 	princ->realm = kmalloc(tmp + 1, GFP_KERNEL);
272 	if (!princ->realm)
273 		return -ENOMEM;
274 	memcpy(princ->realm, xdr, tmp);
275 	princ->realm[tmp] = 0;
276 	toklen -= paddedlen;
277 	xdr += paddedlen >> 2;
278 
279 	_debug("%s/...@%s", princ->name_parts[0], princ->realm);
280 
281 	*_xdr = xdr;
282 	*_toklen = toklen;
283 	_leave(" = 0 [toklen=%u]", toklen);
284 	return 0;
285 }
286 
287 /*
288  * extract a piece of krb5 tagged data
289  */
290 static int rxrpc_krb5_decode_tagged_data(struct krb5_tagged_data *td,
291 					 size_t max_data_size,
292 					 const __be32 **_xdr,
293 					 unsigned int *_toklen)
294 {
295 	const __be32 *xdr = *_xdr;
296 	unsigned int toklen = *_toklen, len, paddedlen;
297 
298 	/* there must be at least one tag and one length word */
299 	if (toklen <= 8)
300 		return -EINVAL;
301 
302 	_enter(",%zu,{%x,%x},%u",
303 	       max_data_size, ntohl(xdr[0]), ntohl(xdr[1]), toklen);
304 
305 	td->tag = ntohl(*xdr++);
306 	len = ntohl(*xdr++);
307 	toklen -= 8;
308 	if (len > max_data_size)
309 		return -EINVAL;
310 	paddedlen = (len + 3) & ~3;
311 	if (paddedlen > toklen)
312 		return -EINVAL;
313 	td->data_len = len;
314 
315 	if (len > 0) {
316 		td->data = kmemdup(xdr, len, GFP_KERNEL);
317 		if (!td->data)
318 			return -ENOMEM;
319 		toklen -= paddedlen;
320 		xdr += paddedlen >> 2;
321 	}
322 
323 	_debug("tag %x len %x", td->tag, td->data_len);
324 
325 	*_xdr = xdr;
326 	*_toklen = toklen;
327 	_leave(" = 0 [toklen=%u]", toklen);
328 	return 0;
329 }
330 
331 /*
332  * extract an array of tagged data
333  */
334 static int rxrpc_krb5_decode_tagged_array(struct krb5_tagged_data **_td,
335 					  u8 *_n_elem,
336 					  u8 max_n_elem,
337 					  size_t max_elem_size,
338 					  const __be32 **_xdr,
339 					  unsigned int *_toklen)
340 {
341 	struct krb5_tagged_data *td;
342 	const __be32 *xdr = *_xdr;
343 	unsigned int toklen = *_toklen, n_elem, loop;
344 	int ret;
345 
346 	/* there must be at least one count */
347 	if (toklen < 4)
348 		return -EINVAL;
349 
350 	_enter(",,%u,%zu,{%x},%u",
351 	       max_n_elem, max_elem_size, ntohl(xdr[0]), toklen);
352 
353 	n_elem = ntohl(*xdr++);
354 	toklen -= 4;
355 	if (n_elem > max_n_elem)
356 		return -EINVAL;
357 	*_n_elem = n_elem;
358 	if (n_elem > 0) {
359 		if (toklen <= (n_elem + 1) * 4)
360 			return -EINVAL;
361 
362 		_debug("n_elem %d", n_elem);
363 
364 		td = kcalloc(n_elem, sizeof(struct krb5_tagged_data),
365 			     GFP_KERNEL);
366 		if (!td)
367 			return -ENOMEM;
368 		*_td = td;
369 
370 		for (loop = 0; loop < n_elem; loop++) {
371 			ret = rxrpc_krb5_decode_tagged_data(&td[loop],
372 							    max_elem_size,
373 							    &xdr, &toklen);
374 			if (ret < 0)
375 				return ret;
376 		}
377 	}
378 
379 	*_xdr = xdr;
380 	*_toklen = toklen;
381 	_leave(" = 0 [toklen=%u]", toklen);
382 	return 0;
383 }
384 
385 /*
386  * extract a krb5 ticket
387  */
388 static int rxrpc_krb5_decode_ticket(u8 **_ticket, u16 *_tktlen,
389 				    const __be32 **_xdr, unsigned int *_toklen)
390 {
391 	const __be32 *xdr = *_xdr;
392 	unsigned int toklen = *_toklen, len, paddedlen;
393 
394 	/* there must be at least one length word */
395 	if (toklen <= 4)
396 		return -EINVAL;
397 
398 	_enter(",{%x},%u", ntohl(xdr[0]), toklen);
399 
400 	len = ntohl(*xdr++);
401 	toklen -= 4;
402 	if (len > AFSTOKEN_K5_TIX_MAX)
403 		return -EINVAL;
404 	paddedlen = (len + 3) & ~3;
405 	if (paddedlen > toklen)
406 		return -EINVAL;
407 	*_tktlen = len;
408 
409 	_debug("ticket len %u", len);
410 
411 	if (len > 0) {
412 		*_ticket = kmemdup(xdr, len, GFP_KERNEL);
413 		if (!*_ticket)
414 			return -ENOMEM;
415 		toklen -= paddedlen;
416 		xdr += paddedlen >> 2;
417 	}
418 
419 	*_xdr = xdr;
420 	*_toklen = toklen;
421 	_leave(" = 0 [toklen=%u]", toklen);
422 	return 0;
423 }
424 
425 /*
426  * parse an RxK5 type XDR format token
427  * - the caller guarantees we have at least 4 words
428  */
429 static int rxrpc_preparse_xdr_rxk5(struct key_preparsed_payload *prep,
430 				   size_t datalen,
431 				   const __be32 *xdr, unsigned int toklen)
432 {
433 	struct rxrpc_key_token *token, **pptoken;
434 	struct rxk5_key *rxk5;
435 	const __be32 *end_xdr = xdr + (toklen >> 2);
436 	int ret;
437 
438 	_enter(",{%x,%x,%x,%x},%u",
439 	       ntohl(xdr[0]), ntohl(xdr[1]), ntohl(xdr[2]), ntohl(xdr[3]),
440 	       toklen);
441 
442 	/* reserve some payload space for this subkey - the length of the token
443 	 * is a reasonable approximation */
444 	prep->quotalen = datalen + toklen;
445 
446 	token = kzalloc(sizeof(*token), GFP_KERNEL);
447 	if (!token)
448 		return -ENOMEM;
449 
450 	rxk5 = kzalloc(sizeof(*rxk5), GFP_KERNEL);
451 	if (!rxk5) {
452 		kfree(token);
453 		return -ENOMEM;
454 	}
455 
456 	token->security_index = RXRPC_SECURITY_RXK5;
457 	token->k5 = rxk5;
458 
459 	/* extract the principals */
460 	ret = rxrpc_krb5_decode_principal(&rxk5->client, &xdr, &toklen);
461 	if (ret < 0)
462 		goto error;
463 	ret = rxrpc_krb5_decode_principal(&rxk5->server, &xdr, &toklen);
464 	if (ret < 0)
465 		goto error;
466 
467 	/* extract the session key and the encoding type (the tag field ->
468 	 * ENCTYPE_xxx) */
469 	ret = rxrpc_krb5_decode_tagged_data(&rxk5->session, AFSTOKEN_DATA_MAX,
470 					    &xdr, &toklen);
471 	if (ret < 0)
472 		goto error;
473 
474 	if (toklen < 4 * 8 + 2 * 4)
475 		goto inval;
476 	rxk5->authtime	= be64_to_cpup((const __be64 *) xdr);
477 	xdr += 2;
478 	rxk5->starttime	= be64_to_cpup((const __be64 *) xdr);
479 	xdr += 2;
480 	rxk5->endtime	= be64_to_cpup((const __be64 *) xdr);
481 	xdr += 2;
482 	rxk5->renew_till = be64_to_cpup((const __be64 *) xdr);
483 	xdr += 2;
484 	rxk5->is_skey = ntohl(*xdr++);
485 	rxk5->flags = ntohl(*xdr++);
486 	toklen -= 4 * 8 + 2 * 4;
487 
488 	_debug("times: a=%llx s=%llx e=%llx rt=%llx",
489 	       rxk5->authtime, rxk5->starttime, rxk5->endtime,
490 	       rxk5->renew_till);
491 	_debug("is_skey=%x flags=%x", rxk5->is_skey, rxk5->flags);
492 
493 	/* extract the permitted client addresses */
494 	ret = rxrpc_krb5_decode_tagged_array(&rxk5->addresses,
495 					     &rxk5->n_addresses,
496 					     AFSTOKEN_K5_ADDRESSES_MAX,
497 					     AFSTOKEN_DATA_MAX,
498 					     &xdr, &toklen);
499 	if (ret < 0)
500 		goto error;
501 
502 	ASSERTCMP((end_xdr - xdr) << 2, ==, toklen);
503 
504 	/* extract the tickets */
505 	ret = rxrpc_krb5_decode_ticket(&rxk5->ticket, &rxk5->ticket_len,
506 				       &xdr, &toklen);
507 	if (ret < 0)
508 		goto error;
509 	ret = rxrpc_krb5_decode_ticket(&rxk5->ticket2, &rxk5->ticket2_len,
510 				       &xdr, &toklen);
511 	if (ret < 0)
512 		goto error;
513 
514 	ASSERTCMP((end_xdr - xdr) << 2, ==, toklen);
515 
516 	/* extract the typed auth data */
517 	ret = rxrpc_krb5_decode_tagged_array(&rxk5->authdata,
518 					     &rxk5->n_authdata,
519 					     AFSTOKEN_K5_AUTHDATA_MAX,
520 					     AFSTOKEN_BDATALN_MAX,
521 					     &xdr, &toklen);
522 	if (ret < 0)
523 		goto error;
524 
525 	ASSERTCMP((end_xdr - xdr) << 2, ==, toklen);
526 
527 	if (toklen != 0)
528 		goto inval;
529 
530 	/* attach the payload */
531 	for (pptoken = (struct rxrpc_key_token **)&prep->payload.data[0];
532 	     *pptoken;
533 	     pptoken = &(*pptoken)->next)
534 		continue;
535 	*pptoken = token;
536 	if (token->kad->expiry < prep->expiry)
537 		prep->expiry = token->kad->expiry;
538 
539 	_leave(" = 0");
540 	return 0;
541 
542 inval:
543 	ret = -EINVAL;
544 error:
545 	rxrpc_rxk5_free(rxk5);
546 	kfree(token);
547 	_leave(" = %d", ret);
548 	return ret;
549 }
550 
551 /*
552  * attempt to parse the data as the XDR format
553  * - the caller guarantees we have more than 7 words
554  */
555 static int rxrpc_preparse_xdr(struct key_preparsed_payload *prep)
556 {
557 	const __be32 *xdr = prep->data, *token;
558 	const char *cp;
559 	unsigned int len, paddedlen, loop, ntoken, toklen, sec_ix;
560 	size_t datalen = prep->datalen;
561 	int ret;
562 
563 	_enter(",{%x,%x,%x,%x},%zu",
564 	       ntohl(xdr[0]), ntohl(xdr[1]), ntohl(xdr[2]), ntohl(xdr[3]),
565 	       prep->datalen);
566 
567 	if (datalen > AFSTOKEN_LENGTH_MAX)
568 		goto not_xdr;
569 
570 	/* XDR is an array of __be32's */
571 	if (datalen & 3)
572 		goto not_xdr;
573 
574 	/* the flags should be 0 (the setpag bit must be handled by
575 	 * userspace) */
576 	if (ntohl(*xdr++) != 0)
577 		goto not_xdr;
578 	datalen -= 4;
579 
580 	/* check the cell name */
581 	len = ntohl(*xdr++);
582 	if (len < 1 || len > AFSTOKEN_CELL_MAX)
583 		goto not_xdr;
584 	datalen -= 4;
585 	paddedlen = (len + 3) & ~3;
586 	if (paddedlen > datalen)
587 		goto not_xdr;
588 
589 	cp = (const char *) xdr;
590 	for (loop = 0; loop < len; loop++)
591 		if (!isprint(cp[loop]))
592 			goto not_xdr;
593 	for (; loop < paddedlen; loop++)
594 		if (cp[loop])
595 			goto not_xdr;
596 	_debug("cellname: [%u/%u] '%*.*s'",
597 	       len, paddedlen, len, len, (const char *) xdr);
598 	datalen -= paddedlen;
599 	xdr += paddedlen >> 2;
600 
601 	/* get the token count */
602 	if (datalen < 12)
603 		goto not_xdr;
604 	ntoken = ntohl(*xdr++);
605 	datalen -= 4;
606 	_debug("ntoken: %x", ntoken);
607 	if (ntoken < 1 || ntoken > AFSTOKEN_MAX)
608 		goto not_xdr;
609 
610 	/* check each token wrapper */
611 	token = xdr;
612 	loop = ntoken;
613 	do {
614 		if (datalen < 8)
615 			goto not_xdr;
616 		toklen = ntohl(*xdr++);
617 		sec_ix = ntohl(*xdr);
618 		datalen -= 4;
619 		_debug("token: [%x/%zx] %x", toklen, datalen, sec_ix);
620 		paddedlen = (toklen + 3) & ~3;
621 		if (toklen < 20 || toklen > datalen || paddedlen > datalen)
622 			goto not_xdr;
623 		datalen -= paddedlen;
624 		xdr += paddedlen >> 2;
625 
626 	} while (--loop > 0);
627 
628 	_debug("remainder: %zu", datalen);
629 	if (datalen != 0)
630 		goto not_xdr;
631 
632 	/* okay: we're going to assume it's valid XDR format
633 	 * - we ignore the cellname, relying on the key to be correctly named
634 	 */
635 	do {
636 		xdr = token;
637 		toklen = ntohl(*xdr++);
638 		token = xdr + ((toklen + 3) >> 2);
639 		sec_ix = ntohl(*xdr++);
640 		toklen -= 4;
641 
642 		_debug("TOKEN type=%u [%p-%p]", sec_ix, xdr, token);
643 
644 		switch (sec_ix) {
645 		case RXRPC_SECURITY_RXKAD:
646 			ret = rxrpc_preparse_xdr_rxkad(prep, datalen, xdr, toklen);
647 			if (ret != 0)
648 				goto error;
649 			break;
650 
651 		case RXRPC_SECURITY_RXK5:
652 			ret = rxrpc_preparse_xdr_rxk5(prep, datalen, xdr, toklen);
653 			if (ret != 0)
654 				goto error;
655 			break;
656 
657 		default:
658 			ret = -EPROTONOSUPPORT;
659 			goto error;
660 		}
661 
662 	} while (--ntoken > 0);
663 
664 	_leave(" = 0");
665 	return 0;
666 
667 not_xdr:
668 	_leave(" = -EPROTO");
669 	return -EPROTO;
670 error:
671 	_leave(" = %d", ret);
672 	return ret;
673 }
674 
675 /*
676  * Preparse an rxrpc defined key.
677  *
678  * Data should be of the form:
679  *	OFFSET	LEN	CONTENT
680  *	0	4	key interface version number
681  *	4	2	security index (type)
682  *	6	2	ticket length
683  *	8	4	key expiry time (time_t)
684  *	12	4	kvno
685  *	16	8	session key
686  *	24	[len]	ticket
687  *
688  * if no data is provided, then a no-security key is made
689  */
690 static int rxrpc_preparse(struct key_preparsed_payload *prep)
691 {
692 	const struct rxrpc_key_data_v1 *v1;
693 	struct rxrpc_key_token *token, **pp;
694 	size_t plen;
695 	u32 kver;
696 	int ret;
697 
698 	_enter("%zu", prep->datalen);
699 
700 	/* handle a no-security key */
701 	if (!prep->data && prep->datalen == 0)
702 		return 0;
703 
704 	/* determine if the XDR payload format is being used */
705 	if (prep->datalen > 7 * 4) {
706 		ret = rxrpc_preparse_xdr(prep);
707 		if (ret != -EPROTO)
708 			return ret;
709 	}
710 
711 	/* get the key interface version number */
712 	ret = -EINVAL;
713 	if (prep->datalen <= 4 || !prep->data)
714 		goto error;
715 	memcpy(&kver, prep->data, sizeof(kver));
716 	prep->data += sizeof(kver);
717 	prep->datalen -= sizeof(kver);
718 
719 	_debug("KEY I/F VERSION: %u", kver);
720 
721 	ret = -EKEYREJECTED;
722 	if (kver != 1)
723 		goto error;
724 
725 	/* deal with a version 1 key */
726 	ret = -EINVAL;
727 	if (prep->datalen < sizeof(*v1))
728 		goto error;
729 
730 	v1 = prep->data;
731 	if (prep->datalen != sizeof(*v1) + v1->ticket_length)
732 		goto error;
733 
734 	_debug("SCIX: %u", v1->security_index);
735 	_debug("TLEN: %u", v1->ticket_length);
736 	_debug("EXPY: %x", v1->expiry);
737 	_debug("KVNO: %u", v1->kvno);
738 	_debug("SKEY: %02x%02x%02x%02x%02x%02x%02x%02x",
739 	       v1->session_key[0], v1->session_key[1],
740 	       v1->session_key[2], v1->session_key[3],
741 	       v1->session_key[4], v1->session_key[5],
742 	       v1->session_key[6], v1->session_key[7]);
743 	if (v1->ticket_length >= 8)
744 		_debug("TCKT: %02x%02x%02x%02x%02x%02x%02x%02x",
745 		       v1->ticket[0], v1->ticket[1],
746 		       v1->ticket[2], v1->ticket[3],
747 		       v1->ticket[4], v1->ticket[5],
748 		       v1->ticket[6], v1->ticket[7]);
749 
750 	ret = -EPROTONOSUPPORT;
751 	if (v1->security_index != RXRPC_SECURITY_RXKAD)
752 		goto error;
753 
754 	plen = sizeof(*token->kad) + v1->ticket_length;
755 	prep->quotalen = plen + sizeof(*token);
756 
757 	ret = -ENOMEM;
758 	token = kzalloc(sizeof(*token), GFP_KERNEL);
759 	if (!token)
760 		goto error;
761 	token->kad = kzalloc(plen, GFP_KERNEL);
762 	if (!token->kad)
763 		goto error_free;
764 
765 	token->security_index		= RXRPC_SECURITY_RXKAD;
766 	token->kad->ticket_len		= v1->ticket_length;
767 	token->kad->expiry		= v1->expiry;
768 	token->kad->kvno		= v1->kvno;
769 	memcpy(&token->kad->session_key, &v1->session_key, 8);
770 	memcpy(&token->kad->ticket, v1->ticket, v1->ticket_length);
771 
772 	/* count the number of tokens attached */
773 	prep->payload.data[1] = (void *)((unsigned long)prep->payload.data[1] + 1);
774 
775 	/* attach the data */
776 	pp = (struct rxrpc_key_token **)&prep->payload.data[0];
777 	while (*pp)
778 		pp = &(*pp)->next;
779 	*pp = token;
780 	if (token->kad->expiry < prep->expiry)
781 		prep->expiry = token->kad->expiry;
782 	token = NULL;
783 	ret = 0;
784 
785 error_free:
786 	kfree(token);
787 error:
788 	return ret;
789 }
790 
791 /*
792  * Free token list.
793  */
794 static void rxrpc_free_token_list(struct rxrpc_key_token *token)
795 {
796 	struct rxrpc_key_token *next;
797 
798 	for (; token; token = next) {
799 		next = token->next;
800 		switch (token->security_index) {
801 		case RXRPC_SECURITY_RXKAD:
802 			kfree(token->kad);
803 			break;
804 		case RXRPC_SECURITY_RXK5:
805 			if (token->k5)
806 				rxrpc_rxk5_free(token->k5);
807 			break;
808 		default:
809 			pr_err("Unknown token type %x on rxrpc key\n",
810 			       token->security_index);
811 			BUG();
812 		}
813 
814 		kfree(token);
815 	}
816 }
817 
818 /*
819  * Clean up preparse data.
820  */
821 static void rxrpc_free_preparse(struct key_preparsed_payload *prep)
822 {
823 	rxrpc_free_token_list(prep->payload.data[0]);
824 }
825 
826 /*
827  * Preparse a server secret key.
828  *
829  * The data should be the 8-byte secret key.
830  */
831 static int rxrpc_preparse_s(struct key_preparsed_payload *prep)
832 {
833 	struct crypto_skcipher *ci;
834 
835 	_enter("%zu", prep->datalen);
836 
837 	if (prep->datalen != 8)
838 		return -EINVAL;
839 
840 	memcpy(&prep->payload.data[2], prep->data, 8);
841 
842 	ci = crypto_alloc_skcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
843 	if (IS_ERR(ci)) {
844 		_leave(" = %ld", PTR_ERR(ci));
845 		return PTR_ERR(ci);
846 	}
847 
848 	if (crypto_skcipher_setkey(ci, prep->data, 8) < 0)
849 		BUG();
850 
851 	prep->payload.data[0] = ci;
852 	_leave(" = 0");
853 	return 0;
854 }
855 
856 /*
857  * Clean up preparse data.
858  */
859 static void rxrpc_free_preparse_s(struct key_preparsed_payload *prep)
860 {
861 	if (prep->payload.data[0])
862 		crypto_free_skcipher(prep->payload.data[0]);
863 }
864 
865 /*
866  * dispose of the data dangling from the corpse of a rxrpc key
867  */
868 static void rxrpc_destroy(struct key *key)
869 {
870 	rxrpc_free_token_list(key->payload.data[0]);
871 }
872 
873 /*
874  * dispose of the data dangling from the corpse of a rxrpc key
875  */
876 static void rxrpc_destroy_s(struct key *key)
877 {
878 	if (key->payload.data[0]) {
879 		crypto_free_skcipher(key->payload.data[0]);
880 		key->payload.data[0] = NULL;
881 	}
882 }
883 
884 /*
885  * describe the rxrpc key
886  */
887 static void rxrpc_describe(const struct key *key, struct seq_file *m)
888 {
889 	seq_puts(m, key->description);
890 }
891 
892 /*
893  * grab the security key for a socket
894  */
895 int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
896 {
897 	struct key *key;
898 	char *description;
899 
900 	_enter("");
901 
902 	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
903 		return -EINVAL;
904 
905 	description = memdup_user_nul(optval, optlen);
906 	if (IS_ERR(description))
907 		return PTR_ERR(description);
908 
909 	key = request_key(&key_type_rxrpc, description, NULL);
910 	if (IS_ERR(key)) {
911 		kfree(description);
912 		_leave(" = %ld", PTR_ERR(key));
913 		return PTR_ERR(key);
914 	}
915 
916 	rx->key = key;
917 	kfree(description);
918 	_leave(" = 0 [key %x]", key->serial);
919 	return 0;
920 }
921 
922 /*
923  * grab the security keyring for a server socket
924  */
925 int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
926 			 int optlen)
927 {
928 	struct key *key;
929 	char *description;
930 
931 	_enter("");
932 
933 	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
934 		return -EINVAL;
935 
936 	description = memdup_user_nul(optval, optlen);
937 	if (IS_ERR(description))
938 		return PTR_ERR(description);
939 
940 	key = request_key(&key_type_keyring, description, NULL);
941 	if (IS_ERR(key)) {
942 		kfree(description);
943 		_leave(" = %ld", PTR_ERR(key));
944 		return PTR_ERR(key);
945 	}
946 
947 	rx->securities = key;
948 	kfree(description);
949 	_leave(" = 0 [key %x]", key->serial);
950 	return 0;
951 }
952 
953 /*
954  * generate a server data key
955  */
956 int rxrpc_get_server_data_key(struct rxrpc_connection *conn,
957 			      const void *session_key,
958 			      time_t expiry,
959 			      u32 kvno)
960 {
961 	const struct cred *cred = current_cred();
962 	struct key *key;
963 	int ret;
964 
965 	struct {
966 		u32 kver;
967 		struct rxrpc_key_data_v1 v1;
968 	} data;
969 
970 	_enter("");
971 
972 	key = key_alloc(&key_type_rxrpc, "x",
973 			GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred, 0,
974 			KEY_ALLOC_NOT_IN_QUOTA, NULL);
975 	if (IS_ERR(key)) {
976 		_leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
977 		return -ENOMEM;
978 	}
979 
980 	_debug("key %d", key_serial(key));
981 
982 	data.kver = 1;
983 	data.v1.security_index = RXRPC_SECURITY_RXKAD;
984 	data.v1.ticket_length = 0;
985 	data.v1.expiry = expiry;
986 	data.v1.kvno = 0;
987 
988 	memcpy(&data.v1.session_key, session_key, sizeof(data.v1.session_key));
989 
990 	ret = key_instantiate_and_link(key, &data, sizeof(data), NULL, NULL);
991 	if (ret < 0)
992 		goto error;
993 
994 	conn->params.key = key;
995 	_leave(" = 0 [%d]", key_serial(key));
996 	return 0;
997 
998 error:
999 	key_revoke(key);
1000 	key_put(key);
1001 	_leave(" = -ENOMEM [ins %d]", ret);
1002 	return -ENOMEM;
1003 }
1004 EXPORT_SYMBOL(rxrpc_get_server_data_key);
1005 
1006 /**
1007  * rxrpc_get_null_key - Generate a null RxRPC key
1008  * @keyname: The name to give the key.
1009  *
1010  * Generate a null RxRPC key that can be used to indicate anonymous security is
1011  * required for a particular domain.
1012  */
1013 struct key *rxrpc_get_null_key(const char *keyname)
1014 {
1015 	const struct cred *cred = current_cred();
1016 	struct key *key;
1017 	int ret;
1018 
1019 	key = key_alloc(&key_type_rxrpc, keyname,
1020 			GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
1021 			KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA, NULL);
1022 	if (IS_ERR(key))
1023 		return key;
1024 
1025 	ret = key_instantiate_and_link(key, NULL, 0, NULL, NULL);
1026 	if (ret < 0) {
1027 		key_revoke(key);
1028 		key_put(key);
1029 		return ERR_PTR(ret);
1030 	}
1031 
1032 	return key;
1033 }
1034 EXPORT_SYMBOL(rxrpc_get_null_key);
1035 
1036 /*
1037  * read the contents of an rxrpc key
1038  * - this returns the result in XDR form
1039  */
1040 static long rxrpc_read(const struct key *key,
1041 		       char __user *buffer, size_t buflen)
1042 {
1043 	const struct rxrpc_key_token *token;
1044 	const struct krb5_principal *princ;
1045 	size_t size;
1046 	__be32 __user *xdr, *oldxdr;
1047 	u32 cnlen, toksize, ntoks, tok, zero;
1048 	u16 toksizes[AFSTOKEN_MAX];
1049 	int loop;
1050 
1051 	_enter("");
1052 
1053 	/* we don't know what form we should return non-AFS keys in */
1054 	if (memcmp(key->description, "afs@", 4) != 0)
1055 		return -EOPNOTSUPP;
1056 	cnlen = strlen(key->description + 4);
1057 
1058 #define RND(X) (((X) + 3) & ~3)
1059 
1060 	/* AFS keys we return in XDR form, so we need to work out the size of
1061 	 * the XDR */
1062 	size = 2 * 4;	/* flags, cellname len */
1063 	size += RND(cnlen);	/* cellname */
1064 	size += 1 * 4;	/* token count */
1065 
1066 	ntoks = 0;
1067 	for (token = key->payload.data[0]; token; token = token->next) {
1068 		toksize = 4;	/* sec index */
1069 
1070 		switch (token->security_index) {
1071 		case RXRPC_SECURITY_RXKAD:
1072 			toksize += 9 * 4;	/* viceid, kvno, key*2 + len, begin,
1073 						 * end, primary, tktlen */
1074 			toksize += RND(token->kad->ticket_len);
1075 			break;
1076 
1077 		case RXRPC_SECURITY_RXK5:
1078 			princ = &token->k5->client;
1079 			toksize += 4 + princ->n_name_parts * 4;
1080 			for (loop = 0; loop < princ->n_name_parts; loop++)
1081 				toksize += RND(strlen(princ->name_parts[loop]));
1082 			toksize += 4 + RND(strlen(princ->realm));
1083 
1084 			princ = &token->k5->server;
1085 			toksize += 4 + princ->n_name_parts * 4;
1086 			for (loop = 0; loop < princ->n_name_parts; loop++)
1087 				toksize += RND(strlen(princ->name_parts[loop]));
1088 			toksize += 4 + RND(strlen(princ->realm));
1089 
1090 			toksize += 8 + RND(token->k5->session.data_len);
1091 
1092 			toksize += 4 * 8 + 2 * 4;
1093 
1094 			toksize += 4 + token->k5->n_addresses * 8;
1095 			for (loop = 0; loop < token->k5->n_addresses; loop++)
1096 				toksize += RND(token->k5->addresses[loop].data_len);
1097 
1098 			toksize += 4 + RND(token->k5->ticket_len);
1099 			toksize += 4 + RND(token->k5->ticket2_len);
1100 
1101 			toksize += 4 + token->k5->n_authdata * 8;
1102 			for (loop = 0; loop < token->k5->n_authdata; loop++)
1103 				toksize += RND(token->k5->authdata[loop].data_len);
1104 			break;
1105 
1106 		default: /* we have a ticket we can't encode */
1107 			BUG();
1108 			continue;
1109 		}
1110 
1111 		_debug("token[%u]: toksize=%u", ntoks, toksize);
1112 		ASSERTCMP(toksize, <=, AFSTOKEN_LENGTH_MAX);
1113 
1114 		toksizes[ntoks++] = toksize;
1115 		size += toksize + 4; /* each token has a length word */
1116 	}
1117 
1118 #undef RND
1119 
1120 	if (!buffer || buflen < size)
1121 		return size;
1122 
1123 	xdr = (__be32 __user *) buffer;
1124 	zero = 0;
1125 #define ENCODE(x)				\
1126 	do {					\
1127 		__be32 y = htonl(x);		\
1128 		if (put_user(y, xdr++) < 0)	\
1129 			goto fault;		\
1130 	} while(0)
1131 #define ENCODE_DATA(l, s)						\
1132 	do {								\
1133 		u32 _l = (l);						\
1134 		ENCODE(l);						\
1135 		if (copy_to_user(xdr, (s), _l) != 0)			\
1136 			goto fault;					\
1137 		if (_l & 3 &&						\
1138 		    copy_to_user((u8 __user *)xdr + _l, &zero, 4 - (_l & 3)) != 0) \
1139 			goto fault;					\
1140 		xdr += (_l + 3) >> 2;					\
1141 	} while(0)
1142 #define ENCODE64(x)					\
1143 	do {						\
1144 		__be64 y = cpu_to_be64(x);		\
1145 		if (copy_to_user(xdr, &y, 8) != 0)	\
1146 			goto fault;			\
1147 		xdr += 8 >> 2;				\
1148 	} while(0)
1149 #define ENCODE_STR(s)				\
1150 	do {					\
1151 		const char *_s = (s);		\
1152 		ENCODE_DATA(strlen(_s), _s);	\
1153 	} while(0)
1154 
1155 	ENCODE(0);					/* flags */
1156 	ENCODE_DATA(cnlen, key->description + 4);	/* cellname */
1157 	ENCODE(ntoks);
1158 
1159 	tok = 0;
1160 	for (token = key->payload.data[0]; token; token = token->next) {
1161 		toksize = toksizes[tok++];
1162 		ENCODE(toksize);
1163 		oldxdr = xdr;
1164 		ENCODE(token->security_index);
1165 
1166 		switch (token->security_index) {
1167 		case RXRPC_SECURITY_RXKAD:
1168 			ENCODE(token->kad->vice_id);
1169 			ENCODE(token->kad->kvno);
1170 			ENCODE_DATA(8, token->kad->session_key);
1171 			ENCODE(token->kad->start);
1172 			ENCODE(token->kad->expiry);
1173 			ENCODE(token->kad->primary_flag);
1174 			ENCODE_DATA(token->kad->ticket_len, token->kad->ticket);
1175 			break;
1176 
1177 		case RXRPC_SECURITY_RXK5:
1178 			princ = &token->k5->client;
1179 			ENCODE(princ->n_name_parts);
1180 			for (loop = 0; loop < princ->n_name_parts; loop++)
1181 				ENCODE_STR(princ->name_parts[loop]);
1182 			ENCODE_STR(princ->realm);
1183 
1184 			princ = &token->k5->server;
1185 			ENCODE(princ->n_name_parts);
1186 			for (loop = 0; loop < princ->n_name_parts; loop++)
1187 				ENCODE_STR(princ->name_parts[loop]);
1188 			ENCODE_STR(princ->realm);
1189 
1190 			ENCODE(token->k5->session.tag);
1191 			ENCODE_DATA(token->k5->session.data_len,
1192 				    token->k5->session.data);
1193 
1194 			ENCODE64(token->k5->authtime);
1195 			ENCODE64(token->k5->starttime);
1196 			ENCODE64(token->k5->endtime);
1197 			ENCODE64(token->k5->renew_till);
1198 			ENCODE(token->k5->is_skey);
1199 			ENCODE(token->k5->flags);
1200 
1201 			ENCODE(token->k5->n_addresses);
1202 			for (loop = 0; loop < token->k5->n_addresses; loop++) {
1203 				ENCODE(token->k5->addresses[loop].tag);
1204 				ENCODE_DATA(token->k5->addresses[loop].data_len,
1205 					    token->k5->addresses[loop].data);
1206 			}
1207 
1208 			ENCODE_DATA(token->k5->ticket_len, token->k5->ticket);
1209 			ENCODE_DATA(token->k5->ticket2_len, token->k5->ticket2);
1210 
1211 			ENCODE(token->k5->n_authdata);
1212 			for (loop = 0; loop < token->k5->n_authdata; loop++) {
1213 				ENCODE(token->k5->authdata[loop].tag);
1214 				ENCODE_DATA(token->k5->authdata[loop].data_len,
1215 					    token->k5->authdata[loop].data);
1216 			}
1217 			break;
1218 
1219 		default:
1220 			BUG();
1221 			break;
1222 		}
1223 
1224 		ASSERTCMP((unsigned long)xdr - (unsigned long)oldxdr, ==,
1225 			  toksize);
1226 	}
1227 
1228 #undef ENCODE_STR
1229 #undef ENCODE_DATA
1230 #undef ENCODE64
1231 #undef ENCODE
1232 
1233 	ASSERTCMP(tok, ==, ntoks);
1234 	ASSERTCMP((char __user *) xdr - buffer, ==, size);
1235 	_leave(" = %zu", size);
1236 	return size;
1237 
1238 fault:
1239 	_leave(" = -EFAULT");
1240 	return -EFAULT;
1241 }
1242