xref: /linux/crypto/crypto_user.c (revision 0883c2c06fb5bcf5b9e008270827e63c09a88c1e) 
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/skcipher.h>
29 #include <crypto/internal/rng.h>
30 #include <crypto/akcipher.h>
31 
32 #include "internal.h"
33 
34 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
35 
36 static DEFINE_MUTEX(crypto_cfg_mutex);
37 
38 /* The crypto netlink socket */
39 static struct sock *crypto_nlsk;
40 
41 struct crypto_dump_info {
42 	struct sk_buff *in_skb;
43 	struct sk_buff *out_skb;
44 	u32 nlmsg_seq;
45 	u16 nlmsg_flags;
46 };
47 
48 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
49 {
50 	struct crypto_alg *q, *alg = NULL;
51 
52 	down_read(&crypto_alg_sem);
53 
54 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
55 		int match = 0;
56 
57 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
58 			continue;
59 
60 		if (strlen(p->cru_driver_name))
61 			match = !strcmp(q->cra_driver_name,
62 					p->cru_driver_name);
63 		else if (!exact)
64 			match = !strcmp(q->cra_name, p->cru_name);
65 
66 		if (!match)
67 			continue;
68 
69 		if (unlikely(!crypto_mod_get(q)))
70 			continue;
71 
72 		alg = q;
73 		break;
74 	}
75 
76 	up_read(&crypto_alg_sem);
77 
78 	return alg;
79 }
80 
81 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
82 {
83 	struct crypto_report_cipher rcipher;
84 
85 	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
86 
87 	rcipher.blocksize = alg->cra_blocksize;
88 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
89 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
90 
91 	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
92 		    sizeof(struct crypto_report_cipher), &rcipher))
93 		goto nla_put_failure;
94 	return 0;
95 
96 nla_put_failure:
97 	return -EMSGSIZE;
98 }
99 
100 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
101 {
102 	struct crypto_report_comp rcomp;
103 
104 	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
105 	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
106 		    sizeof(struct crypto_report_comp), &rcomp))
107 		goto nla_put_failure;
108 	return 0;
109 
110 nla_put_failure:
111 	return -EMSGSIZE;
112 }
113 
114 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
115 {
116 	struct crypto_report_akcipher rakcipher;
117 
118 	strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
119 
120 	if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
121 		    sizeof(struct crypto_report_akcipher), &rakcipher))
122 		goto nla_put_failure;
123 	return 0;
124 
125 nla_put_failure:
126 	return -EMSGSIZE;
127 }
128 
129 static int crypto_report_one(struct crypto_alg *alg,
130 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
131 {
132 	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
133 	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
134 		sizeof(ualg->cru_driver_name));
135 	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
136 		sizeof(ualg->cru_module_name));
137 
138 	ualg->cru_type = 0;
139 	ualg->cru_mask = 0;
140 	ualg->cru_flags = alg->cra_flags;
141 	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
142 
143 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
144 		goto nla_put_failure;
145 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
146 		struct crypto_report_larval rl;
147 
148 		strncpy(rl.type, "larval", sizeof(rl.type));
149 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
150 			    sizeof(struct crypto_report_larval), &rl))
151 			goto nla_put_failure;
152 		goto out;
153 	}
154 
155 	if (alg->cra_type && alg->cra_type->report) {
156 		if (alg->cra_type->report(skb, alg))
157 			goto nla_put_failure;
158 
159 		goto out;
160 	}
161 
162 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
163 	case CRYPTO_ALG_TYPE_CIPHER:
164 		if (crypto_report_cipher(skb, alg))
165 			goto nla_put_failure;
166 
167 		break;
168 	case CRYPTO_ALG_TYPE_COMPRESS:
169 		if (crypto_report_comp(skb, alg))
170 			goto nla_put_failure;
171 
172 		break;
173 
174 	case CRYPTO_ALG_TYPE_AKCIPHER:
175 		if (crypto_report_akcipher(skb, alg))
176 			goto nla_put_failure;
177 
178 		break;
179 	}
180 
181 out:
182 	return 0;
183 
184 nla_put_failure:
185 	return -EMSGSIZE;
186 }
187 
188 static int crypto_report_alg(struct crypto_alg *alg,
189 			     struct crypto_dump_info *info)
190 {
191 	struct sk_buff *in_skb = info->in_skb;
192 	struct sk_buff *skb = info->out_skb;
193 	struct nlmsghdr *nlh;
194 	struct crypto_user_alg *ualg;
195 	int err = 0;
196 
197 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
198 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
199 	if (!nlh) {
200 		err = -EMSGSIZE;
201 		goto out;
202 	}
203 
204 	ualg = nlmsg_data(nlh);
205 
206 	err = crypto_report_one(alg, ualg, skb);
207 	if (err) {
208 		nlmsg_cancel(skb, nlh);
209 		goto out;
210 	}
211 
212 	nlmsg_end(skb, nlh);
213 
214 out:
215 	return err;
216 }
217 
218 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
219 			 struct nlattr **attrs)
220 {
221 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
222 	struct crypto_alg *alg;
223 	struct sk_buff *skb;
224 	struct crypto_dump_info info;
225 	int err;
226 
227 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
228 		return -EINVAL;
229 
230 	alg = crypto_alg_match(p, 0);
231 	if (!alg)
232 		return -ENOENT;
233 
234 	err = -ENOMEM;
235 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
236 	if (!skb)
237 		goto drop_alg;
238 
239 	info.in_skb = in_skb;
240 	info.out_skb = skb;
241 	info.nlmsg_seq = in_nlh->nlmsg_seq;
242 	info.nlmsg_flags = 0;
243 
244 	err = crypto_report_alg(alg, &info);
245 
246 drop_alg:
247 	crypto_mod_put(alg);
248 
249 	if (err)
250 		return err;
251 
252 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
253 }
254 
255 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
256 {
257 	struct crypto_alg *alg;
258 	struct crypto_dump_info info;
259 	int err;
260 
261 	if (cb->args[0])
262 		goto out;
263 
264 	cb->args[0] = 1;
265 
266 	info.in_skb = cb->skb;
267 	info.out_skb = skb;
268 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
269 	info.nlmsg_flags = NLM_F_MULTI;
270 
271 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
272 		err = crypto_report_alg(alg, &info);
273 		if (err)
274 			goto out_err;
275 	}
276 
277 out:
278 	return skb->len;
279 out_err:
280 	return err;
281 }
282 
283 static int crypto_dump_report_done(struct netlink_callback *cb)
284 {
285 	return 0;
286 }
287 
288 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
289 			     struct nlattr **attrs)
290 {
291 	struct crypto_alg *alg;
292 	struct crypto_user_alg *p = nlmsg_data(nlh);
293 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
294 	LIST_HEAD(list);
295 
296 	if (!netlink_capable(skb, CAP_NET_ADMIN))
297 		return -EPERM;
298 
299 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
300 		return -EINVAL;
301 
302 	if (priority && !strlen(p->cru_driver_name))
303 		return -EINVAL;
304 
305 	alg = crypto_alg_match(p, 1);
306 	if (!alg)
307 		return -ENOENT;
308 
309 	down_write(&crypto_alg_sem);
310 
311 	crypto_remove_spawns(alg, &list, NULL);
312 
313 	if (priority)
314 		alg->cra_priority = nla_get_u32(priority);
315 
316 	up_write(&crypto_alg_sem);
317 
318 	crypto_mod_put(alg);
319 	crypto_remove_final(&list);
320 
321 	return 0;
322 }
323 
324 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
325 			  struct nlattr **attrs)
326 {
327 	struct crypto_alg *alg;
328 	struct crypto_user_alg *p = nlmsg_data(nlh);
329 	int err;
330 
331 	if (!netlink_capable(skb, CAP_NET_ADMIN))
332 		return -EPERM;
333 
334 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
335 		return -EINVAL;
336 
337 	alg = crypto_alg_match(p, 1);
338 	if (!alg)
339 		return -ENOENT;
340 
341 	/* We can not unregister core algorithms such as aes-generic.
342 	 * We would loose the reference in the crypto_alg_list to this algorithm
343 	 * if we try to unregister. Unregistering such an algorithm without
344 	 * removing the module is not possible, so we restrict to crypto
345 	 * instances that are build from templates. */
346 	err = -EINVAL;
347 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
348 		goto drop_alg;
349 
350 	err = -EBUSY;
351 	if (atomic_read(&alg->cra_refcnt) > 2)
352 		goto drop_alg;
353 
354 	err = crypto_unregister_instance((struct crypto_instance *)alg);
355 
356 drop_alg:
357 	crypto_mod_put(alg);
358 	return err;
359 }
360 
361 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
362 						   u32 mask)
363 {
364 	int err;
365 	struct crypto_alg *alg;
366 
367 	type = crypto_skcipher_type(type);
368 	mask = crypto_skcipher_mask(mask);
369 
370 	for (;;) {
371 		alg = crypto_lookup_skcipher(name,  type, mask);
372 		if (!IS_ERR(alg))
373 			return alg;
374 
375 		err = PTR_ERR(alg);
376 		if (err != -EAGAIN)
377 			break;
378 		if (fatal_signal_pending(current)) {
379 			err = -EINTR;
380 			break;
381 		}
382 	}
383 
384 	return ERR_PTR(err);
385 }
386 
387 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
388 			  struct nlattr **attrs)
389 {
390 	int exact = 0;
391 	const char *name;
392 	struct crypto_alg *alg;
393 	struct crypto_user_alg *p = nlmsg_data(nlh);
394 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
395 
396 	if (!netlink_capable(skb, CAP_NET_ADMIN))
397 		return -EPERM;
398 
399 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
400 		return -EINVAL;
401 
402 	if (strlen(p->cru_driver_name))
403 		exact = 1;
404 
405 	if (priority && !exact)
406 		return -EINVAL;
407 
408 	alg = crypto_alg_match(p, exact);
409 	if (alg) {
410 		crypto_mod_put(alg);
411 		return -EEXIST;
412 	}
413 
414 	if (strlen(p->cru_driver_name))
415 		name = p->cru_driver_name;
416 	else
417 		name = p->cru_name;
418 
419 	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
420 	case CRYPTO_ALG_TYPE_GIVCIPHER:
421 	case CRYPTO_ALG_TYPE_BLKCIPHER:
422 	case CRYPTO_ALG_TYPE_ABLKCIPHER:
423 		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
424 		break;
425 	default:
426 		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
427 	}
428 
429 	if (IS_ERR(alg))
430 		return PTR_ERR(alg);
431 
432 	down_write(&crypto_alg_sem);
433 
434 	if (priority)
435 		alg->cra_priority = nla_get_u32(priority);
436 
437 	up_write(&crypto_alg_sem);
438 
439 	crypto_mod_put(alg);
440 
441 	return 0;
442 }
443 
444 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
445 			  struct nlattr **attrs)
446 {
447 	if (!netlink_capable(skb, CAP_NET_ADMIN))
448 		return -EPERM;
449 	return crypto_del_default_rng();
450 }
451 
452 #define MSGSIZE(type) sizeof(struct type)
453 
454 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
455 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
456 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
457 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
458 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
459 };
460 
461 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
462 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
463 };
464 
465 #undef MSGSIZE
466 
467 static const struct crypto_link {
468 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
469 	int (*dump)(struct sk_buff *, struct netlink_callback *);
470 	int (*done)(struct netlink_callback *);
471 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
472 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
473 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
474 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
475 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
476 						       .dump = crypto_dump_report,
477 						       .done = crypto_dump_report_done},
478 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
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 		down_read(&crypto_alg_sem);
503 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
504 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
505 
506 		{
507 			struct netlink_dump_control c = {
508 				.dump = link->dump,
509 				.done = link->done,
510 				.min_dump_alloc = dump_alloc,
511 			};
512 			err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
513 		}
514 		up_read(&crypto_alg_sem);
515 
516 		return err;
517 	}
518 
519 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
520 			  crypto_policy);
521 	if (err < 0)
522 		return err;
523 
524 	if (link->doit == NULL)
525 		return -EINVAL;
526 
527 	return link->doit(skb, nlh, attrs);
528 }
529 
530 static void crypto_netlink_rcv(struct sk_buff *skb)
531 {
532 	mutex_lock(&crypto_cfg_mutex);
533 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
534 	mutex_unlock(&crypto_cfg_mutex);
535 }
536 
537 static int __init crypto_user_init(void)
538 {
539 	struct netlink_kernel_cfg cfg = {
540 		.input	= crypto_netlink_rcv,
541 	};
542 
543 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
544 	if (!crypto_nlsk)
545 		return -ENOMEM;
546 
547 	return 0;
548 }
549 
550 static void __exit crypto_user_exit(void)
551 {
552 	netlink_kernel_release(crypto_nlsk);
553 }
554 
555 module_init(crypto_user_init);
556 module_exit(crypto_user_exit);
557 MODULE_LICENSE("GPL");
558 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
559 MODULE_DESCRIPTION("Crypto userspace configuration API");
560 MODULE_ALIAS("net-pf-16-proto-21");
561