xref: /linux/crypto/crypto_user.c (revision 005438a8eef063495ac059d128eea71b58de50e5) 
1 /*
2  * Crypto user configuration API.
3  *
4  * Copyright (C) 2011 secunet Security Networks AG
5  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms and conditions of the GNU General Public License,
9  * version 2, as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  *
16  * You should have received a copy of the GNU General Public License along with
17  * this program; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19  */
20 
21 #include <linux/module.h>
22 #include <linux/crypto.h>
23 #include <linux/cryptouser.h>
24 #include <linux/sched.h>
25 #include <net/netlink.h>
26 #include <linux/security.h>
27 #include <net/net_namespace.h>
28 #include <crypto/internal/aead.h>
29 #include <crypto/internal/skcipher.h>
30 #include <crypto/internal/rng.h>
31 #include <crypto/akcipher.h>
32 
33 #include "internal.h"
34 
35 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
36 
37 static DEFINE_MUTEX(crypto_cfg_mutex);
38 
39 /* The crypto netlink socket */
40 static struct sock *crypto_nlsk;
41 
42 struct crypto_dump_info {
43 	struct sk_buff *in_skb;
44 	struct sk_buff *out_skb;
45 	u32 nlmsg_seq;
46 	u16 nlmsg_flags;
47 };
48 
49 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
50 {
51 	struct crypto_alg *q, *alg = NULL;
52 
53 	down_read(&crypto_alg_sem);
54 
55 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
56 		int match = 0;
57 
58 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
59 			continue;
60 
61 		if (strlen(p->cru_driver_name))
62 			match = !strcmp(q->cra_driver_name,
63 					p->cru_driver_name);
64 		else if (!exact)
65 			match = !strcmp(q->cra_name, p->cru_name);
66 
67 		if (!match)
68 			continue;
69 
70 		if (unlikely(!crypto_mod_get(q)))
71 			continue;
72 
73 		alg = q;
74 		break;
75 	}
76 
77 	up_read(&crypto_alg_sem);
78 
79 	return alg;
80 }
81 
82 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
83 {
84 	struct crypto_report_cipher rcipher;
85 
86 	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
87 
88 	rcipher.blocksize = alg->cra_blocksize;
89 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
90 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
91 
92 	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
93 		    sizeof(struct crypto_report_cipher), &rcipher))
94 		goto nla_put_failure;
95 	return 0;
96 
97 nla_put_failure:
98 	return -EMSGSIZE;
99 }
100 
101 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
102 {
103 	struct crypto_report_comp rcomp;
104 
105 	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
106 	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
107 		    sizeof(struct crypto_report_comp), &rcomp))
108 		goto nla_put_failure;
109 	return 0;
110 
111 nla_put_failure:
112 	return -EMSGSIZE;
113 }
114 
115 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
116 {
117 	struct crypto_report_akcipher rakcipher;
118 
119 	strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
120 
121 	if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
122 		    sizeof(struct crypto_report_akcipher), &rakcipher))
123 		goto nla_put_failure;
124 	return 0;
125 
126 nla_put_failure:
127 	return -EMSGSIZE;
128 }
129 
130 static int crypto_report_one(struct crypto_alg *alg,
131 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
132 {
133 	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
134 	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
135 		sizeof(ualg->cru_driver_name));
136 	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
137 		sizeof(ualg->cru_module_name));
138 
139 	ualg->cru_type = 0;
140 	ualg->cru_mask = 0;
141 	ualg->cru_flags = alg->cra_flags;
142 	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
143 
144 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
145 		goto nla_put_failure;
146 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
147 		struct crypto_report_larval rl;
148 
149 		strncpy(rl.type, "larval", sizeof(rl.type));
150 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
151 			    sizeof(struct crypto_report_larval), &rl))
152 			goto nla_put_failure;
153 		goto out;
154 	}
155 
156 	if (alg->cra_type && alg->cra_type->report) {
157 		if (alg->cra_type->report(skb, alg))
158 			goto nla_put_failure;
159 
160 		goto out;
161 	}
162 
163 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
164 	case CRYPTO_ALG_TYPE_CIPHER:
165 		if (crypto_report_cipher(skb, alg))
166 			goto nla_put_failure;
167 
168 		break;
169 	case CRYPTO_ALG_TYPE_COMPRESS:
170 		if (crypto_report_comp(skb, alg))
171 			goto nla_put_failure;
172 
173 		break;
174 
175 	case CRYPTO_ALG_TYPE_AKCIPHER:
176 		if (crypto_report_akcipher(skb, alg))
177 			goto nla_put_failure;
178 
179 		break;
180 	}
181 
182 out:
183 	return 0;
184 
185 nla_put_failure:
186 	return -EMSGSIZE;
187 }
188 
189 static int crypto_report_alg(struct crypto_alg *alg,
190 			     struct crypto_dump_info *info)
191 {
192 	struct sk_buff *in_skb = info->in_skb;
193 	struct sk_buff *skb = info->out_skb;
194 	struct nlmsghdr *nlh;
195 	struct crypto_user_alg *ualg;
196 	int err = 0;
197 
198 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
199 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
200 	if (!nlh) {
201 		err = -EMSGSIZE;
202 		goto out;
203 	}
204 
205 	ualg = nlmsg_data(nlh);
206 
207 	err = crypto_report_one(alg, ualg, skb);
208 	if (err) {
209 		nlmsg_cancel(skb, nlh);
210 		goto out;
211 	}
212 
213 	nlmsg_end(skb, nlh);
214 
215 out:
216 	return err;
217 }
218 
219 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
220 			 struct nlattr **attrs)
221 {
222 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
223 	struct crypto_alg *alg;
224 	struct sk_buff *skb;
225 	struct crypto_dump_info info;
226 	int err;
227 
228 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
229 		return -EINVAL;
230 
231 	alg = crypto_alg_match(p, 0);
232 	if (!alg)
233 		return -ENOENT;
234 
235 	err = -ENOMEM;
236 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
237 	if (!skb)
238 		goto drop_alg;
239 
240 	info.in_skb = in_skb;
241 	info.out_skb = skb;
242 	info.nlmsg_seq = in_nlh->nlmsg_seq;
243 	info.nlmsg_flags = 0;
244 
245 	err = crypto_report_alg(alg, &info);
246 
247 drop_alg:
248 	crypto_mod_put(alg);
249 
250 	if (err)
251 		return err;
252 
253 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
254 }
255 
256 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
257 {
258 	struct crypto_alg *alg;
259 	struct crypto_dump_info info;
260 	int err;
261 
262 	if (cb->args[0])
263 		goto out;
264 
265 	cb->args[0] = 1;
266 
267 	info.in_skb = cb->skb;
268 	info.out_skb = skb;
269 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
270 	info.nlmsg_flags = NLM_F_MULTI;
271 
272 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
273 		err = crypto_report_alg(alg, &info);
274 		if (err)
275 			goto out_err;
276 	}
277 
278 out:
279 	return skb->len;
280 out_err:
281 	return err;
282 }
283 
284 static int crypto_dump_report_done(struct netlink_callback *cb)
285 {
286 	return 0;
287 }
288 
289 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
290 			     struct nlattr **attrs)
291 {
292 	struct crypto_alg *alg;
293 	struct crypto_user_alg *p = nlmsg_data(nlh);
294 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
295 	LIST_HEAD(list);
296 
297 	if (!netlink_capable(skb, CAP_NET_ADMIN))
298 		return -EPERM;
299 
300 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
301 		return -EINVAL;
302 
303 	if (priority && !strlen(p->cru_driver_name))
304 		return -EINVAL;
305 
306 	alg = crypto_alg_match(p, 1);
307 	if (!alg)
308 		return -ENOENT;
309 
310 	down_write(&crypto_alg_sem);
311 
312 	crypto_remove_spawns(alg, &list, NULL);
313 
314 	if (priority)
315 		alg->cra_priority = nla_get_u32(priority);
316 
317 	up_write(&crypto_alg_sem);
318 
319 	crypto_mod_put(alg);
320 	crypto_remove_final(&list);
321 
322 	return 0;
323 }
324 
325 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
326 			  struct nlattr **attrs)
327 {
328 	struct crypto_alg *alg;
329 	struct crypto_user_alg *p = nlmsg_data(nlh);
330 	int err;
331 
332 	if (!netlink_capable(skb, CAP_NET_ADMIN))
333 		return -EPERM;
334 
335 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
336 		return -EINVAL;
337 
338 	alg = crypto_alg_match(p, 1);
339 	if (!alg)
340 		return -ENOENT;
341 
342 	/* We can not unregister core algorithms such as aes-generic.
343 	 * We would loose the reference in the crypto_alg_list to this algorithm
344 	 * if we try to unregister. Unregistering such an algorithm without
345 	 * removing the module is not possible, so we restrict to crypto
346 	 * instances that are build from templates. */
347 	err = -EINVAL;
348 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
349 		goto drop_alg;
350 
351 	err = -EBUSY;
352 	if (atomic_read(&alg->cra_refcnt) > 2)
353 		goto drop_alg;
354 
355 	err = crypto_unregister_instance((struct crypto_instance *)alg);
356 
357 drop_alg:
358 	crypto_mod_put(alg);
359 	return err;
360 }
361 
362 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
363 						   u32 mask)
364 {
365 	int err;
366 	struct crypto_alg *alg;
367 
368 	type = crypto_skcipher_type(type);
369 	mask = crypto_skcipher_mask(mask);
370 
371 	for (;;) {
372 		alg = crypto_lookup_skcipher(name,  type, mask);
373 		if (!IS_ERR(alg))
374 			return alg;
375 
376 		err = PTR_ERR(alg);
377 		if (err != -EAGAIN)
378 			break;
379 		if (signal_pending(current)) {
380 			err = -EINTR;
381 			break;
382 		}
383 	}
384 
385 	return ERR_PTR(err);
386 }
387 
388 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
389 					       u32 mask)
390 {
391 	int err;
392 	struct crypto_alg *alg;
393 
394 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
395 	type |= CRYPTO_ALG_TYPE_AEAD;
396 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
397 	mask |= CRYPTO_ALG_TYPE_MASK;
398 
399 	for (;;) {
400 		alg = crypto_lookup_aead(name,  type, mask);
401 		if (!IS_ERR(alg))
402 			return alg;
403 
404 		err = PTR_ERR(alg);
405 		if (err != -EAGAIN)
406 			break;
407 		if (signal_pending(current)) {
408 			err = -EINTR;
409 			break;
410 		}
411 	}
412 
413 	return ERR_PTR(err);
414 }
415 
416 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
417 			  struct nlattr **attrs)
418 {
419 	int exact = 0;
420 	const char *name;
421 	struct crypto_alg *alg;
422 	struct crypto_user_alg *p = nlmsg_data(nlh);
423 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
424 
425 	if (!netlink_capable(skb, CAP_NET_ADMIN))
426 		return -EPERM;
427 
428 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
429 		return -EINVAL;
430 
431 	if (strlen(p->cru_driver_name))
432 		exact = 1;
433 
434 	if (priority && !exact)
435 		return -EINVAL;
436 
437 	alg = crypto_alg_match(p, exact);
438 	if (alg) {
439 		crypto_mod_put(alg);
440 		return -EEXIST;
441 	}
442 
443 	if (strlen(p->cru_driver_name))
444 		name = p->cru_driver_name;
445 	else
446 		name = p->cru_name;
447 
448 	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
449 	case CRYPTO_ALG_TYPE_AEAD:
450 		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
451 		break;
452 	case CRYPTO_ALG_TYPE_GIVCIPHER:
453 	case CRYPTO_ALG_TYPE_BLKCIPHER:
454 	case CRYPTO_ALG_TYPE_ABLKCIPHER:
455 		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
456 		break;
457 	default:
458 		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
459 	}
460 
461 	if (IS_ERR(alg))
462 		return PTR_ERR(alg);
463 
464 	down_write(&crypto_alg_sem);
465 
466 	if (priority)
467 		alg->cra_priority = nla_get_u32(priority);
468 
469 	up_write(&crypto_alg_sem);
470 
471 	crypto_mod_put(alg);
472 
473 	return 0;
474 }
475 
476 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
477 			  struct nlattr **attrs)
478 {
479 	if (!netlink_capable(skb, CAP_NET_ADMIN))
480 		return -EPERM;
481 	return crypto_del_default_rng();
482 }
483 
484 #define MSGSIZE(type) sizeof(struct type)
485 
486 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
487 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
488 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
489 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
490 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
491 };
492 
493 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
494 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
495 };
496 
497 #undef MSGSIZE
498 
499 static const struct crypto_link {
500 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
501 	int (*dump)(struct sk_buff *, struct netlink_callback *);
502 	int (*done)(struct netlink_callback *);
503 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
504 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
505 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
506 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
507 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
508 						       .dump = crypto_dump_report,
509 						       .done = crypto_dump_report_done},
510 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
511 };
512 
513 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
514 {
515 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
516 	const struct crypto_link *link;
517 	int type, err;
518 
519 	type = nlh->nlmsg_type;
520 	if (type > CRYPTO_MSG_MAX)
521 		return -EINVAL;
522 
523 	type -= CRYPTO_MSG_BASE;
524 	link = &crypto_dispatch[type];
525 
526 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
527 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
528 		struct crypto_alg *alg;
529 		u16 dump_alloc = 0;
530 
531 		if (link->dump == NULL)
532 			return -EINVAL;
533 
534 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
535 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
536 
537 		{
538 			struct netlink_dump_control c = {
539 				.dump = link->dump,
540 				.done = link->done,
541 				.min_dump_alloc = dump_alloc,
542 			};
543 			return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
544 		}
545 	}
546 
547 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
548 			  crypto_policy);
549 	if (err < 0)
550 		return err;
551 
552 	if (link->doit == NULL)
553 		return -EINVAL;
554 
555 	return link->doit(skb, nlh, attrs);
556 }
557 
558 static void crypto_netlink_rcv(struct sk_buff *skb)
559 {
560 	mutex_lock(&crypto_cfg_mutex);
561 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
562 	mutex_unlock(&crypto_cfg_mutex);
563 }
564 
565 static int __init crypto_user_init(void)
566 {
567 	struct netlink_kernel_cfg cfg = {
568 		.input	= crypto_netlink_rcv,
569 	};
570 
571 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
572 	if (!crypto_nlsk)
573 		return -ENOMEM;
574 
575 	return 0;
576 }
577 
578 static void __exit crypto_user_exit(void)
579 {
580 	netlink_kernel_release(crypto_nlsk);
581 }
582 
583 module_init(crypto_user_init);
584 module_exit(crypto_user_exit);
585 MODULE_LICENSE("GPL");
586 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
587 MODULE_DESCRIPTION("Crypto userspace configuration API");
588 MODULE_ALIAS("net-pf-16-proto-21");
589