xref: /linux/crypto/crypto_user.c (revision e8d235d4d8fb8957bae5f6ed4521115203a00d8b) 
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 
31 #include "internal.h"
32 
33 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
34 
35 static DEFINE_MUTEX(crypto_cfg_mutex);
36 
37 /* The crypto netlink socket */
38 static struct sock *crypto_nlsk;
39 
40 struct crypto_dump_info {
41 	struct sk_buff *in_skb;
42 	struct sk_buff *out_skb;
43 	u32 nlmsg_seq;
44 	u16 nlmsg_flags;
45 };
46 
47 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
48 {
49 	struct crypto_alg *q, *alg = NULL;
50 
51 	down_read(&crypto_alg_sem);
52 
53 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
54 		int match = 0;
55 
56 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
57 			continue;
58 
59 		if (strlen(p->cru_driver_name))
60 			match = !strcmp(q->cra_driver_name,
61 					p->cru_driver_name);
62 		else if (!exact)
63 			match = !strcmp(q->cra_name, p->cru_name);
64 
65 		if (!match)
66 			continue;
67 
68 		if (unlikely(!crypto_mod_get(q)))
69 			continue;
70 
71 		alg = q;
72 		break;
73 	}
74 
75 	up_read(&crypto_alg_sem);
76 
77 	return alg;
78 }
79 
80 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
81 {
82 	struct crypto_report_cipher rcipher;
83 
84 	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
85 
86 	rcipher.blocksize = alg->cra_blocksize;
87 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
88 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
89 
90 	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
91 		    sizeof(struct crypto_report_cipher), &rcipher))
92 		goto nla_put_failure;
93 	return 0;
94 
95 nla_put_failure:
96 	return -EMSGSIZE;
97 }
98 
99 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
100 {
101 	struct crypto_report_comp rcomp;
102 
103 	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
104 	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
105 		    sizeof(struct crypto_report_comp), &rcomp))
106 		goto nla_put_failure;
107 	return 0;
108 
109 nla_put_failure:
110 	return -EMSGSIZE;
111 }
112 
113 static int crypto_report_one(struct crypto_alg *alg,
114 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
115 {
116 	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
117 	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
118 		sizeof(ualg->cru_driver_name));
119 	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
120 		sizeof(ualg->cru_module_name));
121 
122 	ualg->cru_type = 0;
123 	ualg->cru_mask = 0;
124 	ualg->cru_flags = alg->cra_flags;
125 	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
126 
127 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
128 		goto nla_put_failure;
129 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
130 		struct crypto_report_larval rl;
131 
132 		strncpy(rl.type, "larval", sizeof(rl.type));
133 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
134 			    sizeof(struct crypto_report_larval), &rl))
135 			goto nla_put_failure;
136 		goto out;
137 	}
138 
139 	if (alg->cra_type && alg->cra_type->report) {
140 		if (alg->cra_type->report(skb, alg))
141 			goto nla_put_failure;
142 
143 		goto out;
144 	}
145 
146 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
147 	case CRYPTO_ALG_TYPE_CIPHER:
148 		if (crypto_report_cipher(skb, alg))
149 			goto nla_put_failure;
150 
151 		break;
152 	case CRYPTO_ALG_TYPE_COMPRESS:
153 		if (crypto_report_comp(skb, alg))
154 			goto nla_put_failure;
155 
156 		break;
157 	}
158 
159 out:
160 	return 0;
161 
162 nla_put_failure:
163 	return -EMSGSIZE;
164 }
165 
166 static int crypto_report_alg(struct crypto_alg *alg,
167 			     struct crypto_dump_info *info)
168 {
169 	struct sk_buff *in_skb = info->in_skb;
170 	struct sk_buff *skb = info->out_skb;
171 	struct nlmsghdr *nlh;
172 	struct crypto_user_alg *ualg;
173 	int err = 0;
174 
175 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
176 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
177 	if (!nlh) {
178 		err = -EMSGSIZE;
179 		goto out;
180 	}
181 
182 	ualg = nlmsg_data(nlh);
183 
184 	err = crypto_report_one(alg, ualg, skb);
185 	if (err) {
186 		nlmsg_cancel(skb, nlh);
187 		goto out;
188 	}
189 
190 	nlmsg_end(skb, nlh);
191 
192 out:
193 	return err;
194 }
195 
196 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
197 			 struct nlattr **attrs)
198 {
199 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
200 	struct crypto_alg *alg;
201 	struct sk_buff *skb;
202 	struct crypto_dump_info info;
203 	int err;
204 
205 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
206 		return -EINVAL;
207 
208 	alg = crypto_alg_match(p, 0);
209 	if (!alg)
210 		return -ENOENT;
211 
212 	err = -ENOMEM;
213 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
214 	if (!skb)
215 		goto drop_alg;
216 
217 	info.in_skb = in_skb;
218 	info.out_skb = skb;
219 	info.nlmsg_seq = in_nlh->nlmsg_seq;
220 	info.nlmsg_flags = 0;
221 
222 	err = crypto_report_alg(alg, &info);
223 
224 drop_alg:
225 	crypto_mod_put(alg);
226 
227 	if (err)
228 		return err;
229 
230 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
231 }
232 
233 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
234 {
235 	struct crypto_alg *alg;
236 	struct crypto_dump_info info;
237 	int err;
238 
239 	if (cb->args[0])
240 		goto out;
241 
242 	cb->args[0] = 1;
243 
244 	info.in_skb = cb->skb;
245 	info.out_skb = skb;
246 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
247 	info.nlmsg_flags = NLM_F_MULTI;
248 
249 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
250 		err = crypto_report_alg(alg, &info);
251 		if (err)
252 			goto out_err;
253 	}
254 
255 out:
256 	return skb->len;
257 out_err:
258 	return err;
259 }
260 
261 static int crypto_dump_report_done(struct netlink_callback *cb)
262 {
263 	return 0;
264 }
265 
266 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
267 			     struct nlattr **attrs)
268 {
269 	struct crypto_alg *alg;
270 	struct crypto_user_alg *p = nlmsg_data(nlh);
271 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
272 	LIST_HEAD(list);
273 
274 	if (!netlink_capable(skb, CAP_NET_ADMIN))
275 		return -EPERM;
276 
277 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
278 		return -EINVAL;
279 
280 	if (priority && !strlen(p->cru_driver_name))
281 		return -EINVAL;
282 
283 	alg = crypto_alg_match(p, 1);
284 	if (!alg)
285 		return -ENOENT;
286 
287 	down_write(&crypto_alg_sem);
288 
289 	crypto_remove_spawns(alg, &list, NULL);
290 
291 	if (priority)
292 		alg->cra_priority = nla_get_u32(priority);
293 
294 	up_write(&crypto_alg_sem);
295 
296 	crypto_mod_put(alg);
297 	crypto_remove_final(&list);
298 
299 	return 0;
300 }
301 
302 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
303 			  struct nlattr **attrs)
304 {
305 	struct crypto_alg *alg;
306 	struct crypto_user_alg *p = nlmsg_data(nlh);
307 	int err;
308 
309 	if (!netlink_capable(skb, CAP_NET_ADMIN))
310 		return -EPERM;
311 
312 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
313 		return -EINVAL;
314 
315 	alg = crypto_alg_match(p, 1);
316 	if (!alg)
317 		return -ENOENT;
318 
319 	/* We can not unregister core algorithms such as aes-generic.
320 	 * We would loose the reference in the crypto_alg_list to this algorithm
321 	 * if we try to unregister. Unregistering such an algorithm without
322 	 * removing the module is not possible, so we restrict to crypto
323 	 * instances that are build from templates. */
324 	err = -EINVAL;
325 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
326 		goto drop_alg;
327 
328 	err = -EBUSY;
329 	if (atomic_read(&alg->cra_refcnt) > 2)
330 		goto drop_alg;
331 
332 	err = crypto_unregister_instance((struct crypto_instance *)alg);
333 
334 drop_alg:
335 	crypto_mod_put(alg);
336 	return err;
337 }
338 
339 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
340 						   u32 mask)
341 {
342 	int err;
343 	struct crypto_alg *alg;
344 
345 	type = crypto_skcipher_type(type);
346 	mask = crypto_skcipher_mask(mask);
347 
348 	for (;;) {
349 		alg = crypto_lookup_skcipher(name,  type, mask);
350 		if (!IS_ERR(alg))
351 			return alg;
352 
353 		err = PTR_ERR(alg);
354 		if (err != -EAGAIN)
355 			break;
356 		if (signal_pending(current)) {
357 			err = -EINTR;
358 			break;
359 		}
360 	}
361 
362 	return ERR_PTR(err);
363 }
364 
365 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
366 					       u32 mask)
367 {
368 	int err;
369 	struct crypto_alg *alg;
370 
371 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
372 	type |= CRYPTO_ALG_TYPE_AEAD;
373 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
374 	mask |= CRYPTO_ALG_TYPE_MASK;
375 
376 	for (;;) {
377 		alg = crypto_lookup_aead(name,  type, mask);
378 		if (!IS_ERR(alg))
379 			return alg;
380 
381 		err = PTR_ERR(alg);
382 		if (err != -EAGAIN)
383 			break;
384 		if (signal_pending(current)) {
385 			err = -EINTR;
386 			break;
387 		}
388 	}
389 
390 	return ERR_PTR(err);
391 }
392 
393 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
394 			  struct nlattr **attrs)
395 {
396 	int exact = 0;
397 	const char *name;
398 	struct crypto_alg *alg;
399 	struct crypto_user_alg *p = nlmsg_data(nlh);
400 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
401 
402 	if (!netlink_capable(skb, CAP_NET_ADMIN))
403 		return -EPERM;
404 
405 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
406 		return -EINVAL;
407 
408 	if (strlen(p->cru_driver_name))
409 		exact = 1;
410 
411 	if (priority && !exact)
412 		return -EINVAL;
413 
414 	alg = crypto_alg_match(p, exact);
415 	if (alg) {
416 		crypto_mod_put(alg);
417 		return -EEXIST;
418 	}
419 
420 	if (strlen(p->cru_driver_name))
421 		name = p->cru_driver_name;
422 	else
423 		name = p->cru_name;
424 
425 	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
426 	case CRYPTO_ALG_TYPE_AEAD:
427 		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
428 		break;
429 	case CRYPTO_ALG_TYPE_GIVCIPHER:
430 	case CRYPTO_ALG_TYPE_BLKCIPHER:
431 	case CRYPTO_ALG_TYPE_ABLKCIPHER:
432 		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
433 		break;
434 	default:
435 		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
436 	}
437 
438 	if (IS_ERR(alg))
439 		return PTR_ERR(alg);
440 
441 	down_write(&crypto_alg_sem);
442 
443 	if (priority)
444 		alg->cra_priority = nla_get_u32(priority);
445 
446 	up_write(&crypto_alg_sem);
447 
448 	crypto_mod_put(alg);
449 
450 	return 0;
451 }
452 
453 #define MSGSIZE(type) sizeof(struct type)
454 
455 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
456 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
457 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
458 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
459 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
460 };
461 
462 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
463 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
464 };
465 
466 #undef MSGSIZE
467 
468 static const struct crypto_link {
469 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
470 	int (*dump)(struct sk_buff *, struct netlink_callback *);
471 	int (*done)(struct netlink_callback *);
472 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
473 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
474 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
475 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
476 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
477 						       .dump = crypto_dump_report,
478 						       .done = crypto_dump_report_done},
479 };
480 
481 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
482 {
483 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
484 	const struct crypto_link *link;
485 	int type, err;
486 
487 	type = nlh->nlmsg_type;
488 	if (type > CRYPTO_MSG_MAX)
489 		return -EINVAL;
490 
491 	type -= CRYPTO_MSG_BASE;
492 	link = &crypto_dispatch[type];
493 
494 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
495 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
496 		struct crypto_alg *alg;
497 		u16 dump_alloc = 0;
498 
499 		if (link->dump == NULL)
500 			return -EINVAL;
501 
502 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
503 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
504 
505 		{
506 			struct netlink_dump_control c = {
507 				.dump = link->dump,
508 				.done = link->done,
509 				.min_dump_alloc = dump_alloc,
510 			};
511 			return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
512 		}
513 	}
514 
515 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
516 			  crypto_policy);
517 	if (err < 0)
518 		return err;
519 
520 	if (link->doit == NULL)
521 		return -EINVAL;
522 
523 	return link->doit(skb, nlh, attrs);
524 }
525 
526 static void crypto_netlink_rcv(struct sk_buff *skb)
527 {
528 	mutex_lock(&crypto_cfg_mutex);
529 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
530 	mutex_unlock(&crypto_cfg_mutex);
531 }
532 
533 static int __init crypto_user_init(void)
534 {
535 	struct netlink_kernel_cfg cfg = {
536 		.input	= crypto_netlink_rcv,
537 	};
538 
539 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
540 	if (!crypto_nlsk)
541 		return -ENOMEM;
542 
543 	return 0;
544 }
545 
546 static void __exit crypto_user_exit(void)
547 {
548 	netlink_kernel_release(crypto_nlsk);
549 }
550 
551 module_init(crypto_user_init);
552 module_exit(crypto_user_exit);
553 MODULE_LICENSE("GPL");
554 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
555 MODULE_DESCRIPTION("Crypto userspace configuration API");
556 MODULE_ALIAS("net-pf-16-proto-21");
557