xref: /linux/crypto/crypto_user.c (revision 6084a6e23c971ef703229ee1aec68d01688578d6) 
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 			alg = q;
67 			break;
68 		}
69 	}
70 
71 	up_read(&crypto_alg_sem);
72 
73 	return alg;
74 }
75 
76 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
77 {
78 	struct crypto_report_cipher rcipher;
79 
80 	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
81 
82 	rcipher.blocksize = alg->cra_blocksize;
83 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
84 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
85 
86 	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
87 		    sizeof(struct crypto_report_cipher), &rcipher))
88 		goto nla_put_failure;
89 	return 0;
90 
91 nla_put_failure:
92 	return -EMSGSIZE;
93 }
94 
95 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
96 {
97 	struct crypto_report_comp rcomp;
98 
99 	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
100 	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
101 		    sizeof(struct crypto_report_comp), &rcomp))
102 		goto nla_put_failure;
103 	return 0;
104 
105 nla_put_failure:
106 	return -EMSGSIZE;
107 }
108 
109 static int crypto_report_one(struct crypto_alg *alg,
110 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
111 {
112 	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
113 	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
114 		sizeof(ualg->cru_driver_name));
115 	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
116 		sizeof(ualg->cru_module_name));
117 
118 	ualg->cru_type = 0;
119 	ualg->cru_mask = 0;
120 	ualg->cru_flags = alg->cra_flags;
121 	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
122 
123 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
124 		goto nla_put_failure;
125 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
126 		struct crypto_report_larval rl;
127 
128 		strncpy(rl.type, "larval", sizeof(rl.type));
129 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
130 			    sizeof(struct crypto_report_larval), &rl))
131 			goto nla_put_failure;
132 		goto out;
133 	}
134 
135 	if (alg->cra_type && alg->cra_type->report) {
136 		if (alg->cra_type->report(skb, alg))
137 			goto nla_put_failure;
138 
139 		goto out;
140 	}
141 
142 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
143 	case CRYPTO_ALG_TYPE_CIPHER:
144 		if (crypto_report_cipher(skb, alg))
145 			goto nla_put_failure;
146 
147 		break;
148 	case CRYPTO_ALG_TYPE_COMPRESS:
149 		if (crypto_report_comp(skb, alg))
150 			goto nla_put_failure;
151 
152 		break;
153 	}
154 
155 out:
156 	return 0;
157 
158 nla_put_failure:
159 	return -EMSGSIZE;
160 }
161 
162 static int crypto_report_alg(struct crypto_alg *alg,
163 			     struct crypto_dump_info *info)
164 {
165 	struct sk_buff *in_skb = info->in_skb;
166 	struct sk_buff *skb = info->out_skb;
167 	struct nlmsghdr *nlh;
168 	struct crypto_user_alg *ualg;
169 	int err = 0;
170 
171 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
172 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
173 	if (!nlh) {
174 		err = -EMSGSIZE;
175 		goto out;
176 	}
177 
178 	ualg = nlmsg_data(nlh);
179 
180 	err = crypto_report_one(alg, ualg, skb);
181 	if (err) {
182 		nlmsg_cancel(skb, nlh);
183 		goto out;
184 	}
185 
186 	nlmsg_end(skb, nlh);
187 
188 out:
189 	return err;
190 }
191 
192 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
193 			 struct nlattr **attrs)
194 {
195 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
196 	struct crypto_alg *alg;
197 	struct sk_buff *skb;
198 	struct crypto_dump_info info;
199 	int err;
200 
201 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
202 		return -EINVAL;
203 
204 	if (!p->cru_driver_name[0])
205 		return -EINVAL;
206 
207 	alg = crypto_alg_match(p, 1);
208 	if (!alg)
209 		return -ENOENT;
210 
211 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
212 	if (!skb)
213 		return -ENOMEM;
214 
215 	info.in_skb = in_skb;
216 	info.out_skb = skb;
217 	info.nlmsg_seq = in_nlh->nlmsg_seq;
218 	info.nlmsg_flags = 0;
219 
220 	err = crypto_report_alg(alg, &info);
221 	if (err)
222 		return err;
223 
224 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
225 }
226 
227 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
228 {
229 	struct crypto_alg *alg;
230 	struct crypto_dump_info info;
231 	int err;
232 
233 	if (cb->args[0])
234 		goto out;
235 
236 	cb->args[0] = 1;
237 
238 	info.in_skb = cb->skb;
239 	info.out_skb = skb;
240 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
241 	info.nlmsg_flags = NLM_F_MULTI;
242 
243 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
244 		err = crypto_report_alg(alg, &info);
245 		if (err)
246 			goto out_err;
247 	}
248 
249 out:
250 	return skb->len;
251 out_err:
252 	return err;
253 }
254 
255 static int crypto_dump_report_done(struct netlink_callback *cb)
256 {
257 	return 0;
258 }
259 
260 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
261 			     struct nlattr **attrs)
262 {
263 	struct crypto_alg *alg;
264 	struct crypto_user_alg *p = nlmsg_data(nlh);
265 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
266 	LIST_HEAD(list);
267 
268 	if (!netlink_capable(skb, CAP_NET_ADMIN))
269 		return -EPERM;
270 
271 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
272 		return -EINVAL;
273 
274 	if (priority && !strlen(p->cru_driver_name))
275 		return -EINVAL;
276 
277 	alg = crypto_alg_match(p, 1);
278 	if (!alg)
279 		return -ENOENT;
280 
281 	down_write(&crypto_alg_sem);
282 
283 	crypto_remove_spawns(alg, &list, NULL);
284 
285 	if (priority)
286 		alg->cra_priority = nla_get_u32(priority);
287 
288 	up_write(&crypto_alg_sem);
289 
290 	crypto_remove_final(&list);
291 
292 	return 0;
293 }
294 
295 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
296 			  struct nlattr **attrs)
297 {
298 	struct crypto_alg *alg;
299 	struct crypto_user_alg *p = nlmsg_data(nlh);
300 
301 	if (!netlink_capable(skb, CAP_NET_ADMIN))
302 		return -EPERM;
303 
304 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
305 		return -EINVAL;
306 
307 	alg = crypto_alg_match(p, 1);
308 	if (!alg)
309 		return -ENOENT;
310 
311 	/* We can not unregister core algorithms such as aes-generic.
312 	 * We would loose the reference in the crypto_alg_list to this algorithm
313 	 * if we try to unregister. Unregistering such an algorithm without
314 	 * removing the module is not possible, so we restrict to crypto
315 	 * instances that are build from templates. */
316 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
317 		return -EINVAL;
318 
319 	if (atomic_read(&alg->cra_refcnt) != 1)
320 		return -EBUSY;
321 
322 	return crypto_unregister_instance(alg);
323 }
324 
325 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
326 						   u32 mask)
327 {
328 	int err;
329 	struct crypto_alg *alg;
330 
331 	type = crypto_skcipher_type(type);
332 	mask = crypto_skcipher_mask(mask);
333 
334 	for (;;) {
335 		alg = crypto_lookup_skcipher(name,  type, mask);
336 		if (!IS_ERR(alg))
337 			return alg;
338 
339 		err = PTR_ERR(alg);
340 		if (err != -EAGAIN)
341 			break;
342 		if (signal_pending(current)) {
343 			err = -EINTR;
344 			break;
345 		}
346 	}
347 
348 	return ERR_PTR(err);
349 }
350 
351 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
352 					       u32 mask)
353 {
354 	int err;
355 	struct crypto_alg *alg;
356 
357 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
358 	type |= CRYPTO_ALG_TYPE_AEAD;
359 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
360 	mask |= CRYPTO_ALG_TYPE_MASK;
361 
362 	for (;;) {
363 		alg = crypto_lookup_aead(name,  type, mask);
364 		if (!IS_ERR(alg))
365 			return alg;
366 
367 		err = PTR_ERR(alg);
368 		if (err != -EAGAIN)
369 			break;
370 		if (signal_pending(current)) {
371 			err = -EINTR;
372 			break;
373 		}
374 	}
375 
376 	return ERR_PTR(err);
377 }
378 
379 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
380 			  struct nlattr **attrs)
381 {
382 	int exact = 0;
383 	const char *name;
384 	struct crypto_alg *alg;
385 	struct crypto_user_alg *p = nlmsg_data(nlh);
386 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
387 
388 	if (!netlink_capable(skb, CAP_NET_ADMIN))
389 		return -EPERM;
390 
391 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
392 		return -EINVAL;
393 
394 	if (strlen(p->cru_driver_name))
395 		exact = 1;
396 
397 	if (priority && !exact)
398 		return -EINVAL;
399 
400 	alg = crypto_alg_match(p, exact);
401 	if (alg)
402 		return -EEXIST;
403 
404 	if (strlen(p->cru_driver_name))
405 		name = p->cru_driver_name;
406 	else
407 		name = p->cru_name;
408 
409 	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
410 	case CRYPTO_ALG_TYPE_AEAD:
411 		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
412 		break;
413 	case CRYPTO_ALG_TYPE_GIVCIPHER:
414 	case CRYPTO_ALG_TYPE_BLKCIPHER:
415 	case CRYPTO_ALG_TYPE_ABLKCIPHER:
416 		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
417 		break;
418 	default:
419 		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
420 	}
421 
422 	if (IS_ERR(alg))
423 		return PTR_ERR(alg);
424 
425 	down_write(&crypto_alg_sem);
426 
427 	if (priority)
428 		alg->cra_priority = nla_get_u32(priority);
429 
430 	up_write(&crypto_alg_sem);
431 
432 	crypto_mod_put(alg);
433 
434 	return 0;
435 }
436 
437 #define MSGSIZE(type) sizeof(struct type)
438 
439 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
440 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
441 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
442 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
443 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
444 };
445 
446 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
447 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
448 };
449 
450 #undef MSGSIZE
451 
452 static const struct crypto_link {
453 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
454 	int (*dump)(struct sk_buff *, struct netlink_callback *);
455 	int (*done)(struct netlink_callback *);
456 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
457 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
458 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
459 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
460 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
461 						       .dump = crypto_dump_report,
462 						       .done = crypto_dump_report_done},
463 };
464 
465 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
466 {
467 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
468 	const struct crypto_link *link;
469 	int type, err;
470 
471 	type = nlh->nlmsg_type;
472 	if (type > CRYPTO_MSG_MAX)
473 		return -EINVAL;
474 
475 	type -= CRYPTO_MSG_BASE;
476 	link = &crypto_dispatch[type];
477 
478 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
479 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
480 		struct crypto_alg *alg;
481 		u16 dump_alloc = 0;
482 
483 		if (link->dump == NULL)
484 			return -EINVAL;
485 
486 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
487 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
488 
489 		{
490 			struct netlink_dump_control c = {
491 				.dump = link->dump,
492 				.done = link->done,
493 				.min_dump_alloc = dump_alloc,
494 			};
495 			return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
496 		}
497 	}
498 
499 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
500 			  crypto_policy);
501 	if (err < 0)
502 		return err;
503 
504 	if (link->doit == NULL)
505 		return -EINVAL;
506 
507 	return link->doit(skb, nlh, attrs);
508 }
509 
510 static void crypto_netlink_rcv(struct sk_buff *skb)
511 {
512 	mutex_lock(&crypto_cfg_mutex);
513 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
514 	mutex_unlock(&crypto_cfg_mutex);
515 }
516 
517 static int __init crypto_user_init(void)
518 {
519 	struct netlink_kernel_cfg cfg = {
520 		.input	= crypto_netlink_rcv,
521 	};
522 
523 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
524 	if (!crypto_nlsk)
525 		return -ENOMEM;
526 
527 	return 0;
528 }
529 
530 static void __exit crypto_user_exit(void)
531 {
532 	netlink_kernel_release(crypto_nlsk);
533 }
534 
535 module_init(crypto_user_init);
536 module_exit(crypto_user_exit);
537 MODULE_LICENSE("GPL");
538 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
539 MODULE_DESCRIPTION("Crypto userspace configuration API");
540