xref: /linux/crypto/crypto_user.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7) 
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 	alg = crypto_alg_match(p, 0);
205 	if (!alg)
206 		return -ENOENT;
207 
208 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
209 	if (!skb)
210 		return -ENOMEM;
211 
212 	info.in_skb = in_skb;
213 	info.out_skb = skb;
214 	info.nlmsg_seq = in_nlh->nlmsg_seq;
215 	info.nlmsg_flags = 0;
216 
217 	err = crypto_report_alg(alg, &info);
218 	if (err)
219 		return err;
220 
221 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
222 }
223 
224 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
225 {
226 	struct crypto_alg *alg;
227 	struct crypto_dump_info info;
228 	int err;
229 
230 	if (cb->args[0])
231 		goto out;
232 
233 	cb->args[0] = 1;
234 
235 	info.in_skb = cb->skb;
236 	info.out_skb = skb;
237 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
238 	info.nlmsg_flags = NLM_F_MULTI;
239 
240 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
241 		err = crypto_report_alg(alg, &info);
242 		if (err)
243 			goto out_err;
244 	}
245 
246 out:
247 	return skb->len;
248 out_err:
249 	return err;
250 }
251 
252 static int crypto_dump_report_done(struct netlink_callback *cb)
253 {
254 	return 0;
255 }
256 
257 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
258 			     struct nlattr **attrs)
259 {
260 	struct crypto_alg *alg;
261 	struct crypto_user_alg *p = nlmsg_data(nlh);
262 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
263 	LIST_HEAD(list);
264 
265 	if (!netlink_capable(skb, CAP_NET_ADMIN))
266 		return -EPERM;
267 
268 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
269 		return -EINVAL;
270 
271 	if (priority && !strlen(p->cru_driver_name))
272 		return -EINVAL;
273 
274 	alg = crypto_alg_match(p, 1);
275 	if (!alg)
276 		return -ENOENT;
277 
278 	down_write(&crypto_alg_sem);
279 
280 	crypto_remove_spawns(alg, &list, NULL);
281 
282 	if (priority)
283 		alg->cra_priority = nla_get_u32(priority);
284 
285 	up_write(&crypto_alg_sem);
286 
287 	crypto_remove_final(&list);
288 
289 	return 0;
290 }
291 
292 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
293 			  struct nlattr **attrs)
294 {
295 	struct crypto_alg *alg;
296 	struct crypto_user_alg *p = nlmsg_data(nlh);
297 
298 	if (!netlink_capable(skb, CAP_NET_ADMIN))
299 		return -EPERM;
300 
301 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
302 		return -EINVAL;
303 
304 	alg = crypto_alg_match(p, 1);
305 	if (!alg)
306 		return -ENOENT;
307 
308 	/* We can not unregister core algorithms such as aes-generic.
309 	 * We would loose the reference in the crypto_alg_list to this algorithm
310 	 * if we try to unregister. Unregistering such an algorithm without
311 	 * removing the module is not possible, so we restrict to crypto
312 	 * instances that are build from templates. */
313 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
314 		return -EINVAL;
315 
316 	if (atomic_read(&alg->cra_refcnt) != 1)
317 		return -EBUSY;
318 
319 	return crypto_unregister_instance(alg);
320 }
321 
322 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
323 						   u32 mask)
324 {
325 	int err;
326 	struct crypto_alg *alg;
327 
328 	type = crypto_skcipher_type(type);
329 	mask = crypto_skcipher_mask(mask);
330 
331 	for (;;) {
332 		alg = crypto_lookup_skcipher(name,  type, mask);
333 		if (!IS_ERR(alg))
334 			return alg;
335 
336 		err = PTR_ERR(alg);
337 		if (err != -EAGAIN)
338 			break;
339 		if (signal_pending(current)) {
340 			err = -EINTR;
341 			break;
342 		}
343 	}
344 
345 	return ERR_PTR(err);
346 }
347 
348 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
349 					       u32 mask)
350 {
351 	int err;
352 	struct crypto_alg *alg;
353 
354 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
355 	type |= CRYPTO_ALG_TYPE_AEAD;
356 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
357 	mask |= CRYPTO_ALG_TYPE_MASK;
358 
359 	for (;;) {
360 		alg = crypto_lookup_aead(name,  type, mask);
361 		if (!IS_ERR(alg))
362 			return alg;
363 
364 		err = PTR_ERR(alg);
365 		if (err != -EAGAIN)
366 			break;
367 		if (signal_pending(current)) {
368 			err = -EINTR;
369 			break;
370 		}
371 	}
372 
373 	return ERR_PTR(err);
374 }
375 
376 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
377 			  struct nlattr **attrs)
378 {
379 	int exact = 0;
380 	const char *name;
381 	struct crypto_alg *alg;
382 	struct crypto_user_alg *p = nlmsg_data(nlh);
383 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
384 
385 	if (!netlink_capable(skb, CAP_NET_ADMIN))
386 		return -EPERM;
387 
388 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
389 		return -EINVAL;
390 
391 	if (strlen(p->cru_driver_name))
392 		exact = 1;
393 
394 	if (priority && !exact)
395 		return -EINVAL;
396 
397 	alg = crypto_alg_match(p, exact);
398 	if (alg)
399 		return -EEXIST;
400 
401 	if (strlen(p->cru_driver_name))
402 		name = p->cru_driver_name;
403 	else
404 		name = p->cru_name;
405 
406 	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
407 	case CRYPTO_ALG_TYPE_AEAD:
408 		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
409 		break;
410 	case CRYPTO_ALG_TYPE_GIVCIPHER:
411 	case CRYPTO_ALG_TYPE_BLKCIPHER:
412 	case CRYPTO_ALG_TYPE_ABLKCIPHER:
413 		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
414 		break;
415 	default:
416 		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
417 	}
418 
419 	if (IS_ERR(alg))
420 		return PTR_ERR(alg);
421 
422 	down_write(&crypto_alg_sem);
423 
424 	if (priority)
425 		alg->cra_priority = nla_get_u32(priority);
426 
427 	up_write(&crypto_alg_sem);
428 
429 	crypto_mod_put(alg);
430 
431 	return 0;
432 }
433 
434 #define MSGSIZE(type) sizeof(struct type)
435 
436 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
437 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
438 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
439 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
440 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
441 };
442 
443 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
444 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
445 };
446 
447 #undef MSGSIZE
448 
449 static const struct crypto_link {
450 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
451 	int (*dump)(struct sk_buff *, struct netlink_callback *);
452 	int (*done)(struct netlink_callback *);
453 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
454 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
455 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
456 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
457 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
458 						       .dump = crypto_dump_report,
459 						       .done = crypto_dump_report_done},
460 };
461 
462 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
463 {
464 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
465 	const struct crypto_link *link;
466 	int type, err;
467 
468 	type = nlh->nlmsg_type;
469 	if (type > CRYPTO_MSG_MAX)
470 		return -EINVAL;
471 
472 	type -= CRYPTO_MSG_BASE;
473 	link = &crypto_dispatch[type];
474 
475 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
476 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
477 		struct crypto_alg *alg;
478 		u16 dump_alloc = 0;
479 
480 		if (link->dump == NULL)
481 			return -EINVAL;
482 
483 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
484 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
485 
486 		{
487 			struct netlink_dump_control c = {
488 				.dump = link->dump,
489 				.done = link->done,
490 				.min_dump_alloc = dump_alloc,
491 			};
492 			return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
493 		}
494 	}
495 
496 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
497 			  crypto_policy);
498 	if (err < 0)
499 		return err;
500 
501 	if (link->doit == NULL)
502 		return -EINVAL;
503 
504 	return link->doit(skb, nlh, attrs);
505 }
506 
507 static void crypto_netlink_rcv(struct sk_buff *skb)
508 {
509 	mutex_lock(&crypto_cfg_mutex);
510 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
511 	mutex_unlock(&crypto_cfg_mutex);
512 }
513 
514 static int __init crypto_user_init(void)
515 {
516 	struct netlink_kernel_cfg cfg = {
517 		.input	= crypto_netlink_rcv,
518 	};
519 
520 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
521 	if (!crypto_nlsk)
522 		return -ENOMEM;
523 
524 	return 0;
525 }
526 
527 static void __exit crypto_user_exit(void)
528 {
529 	netlink_kernel_release(crypto_nlsk);
530 }
531 
532 module_init(crypto_user_init);
533 module_exit(crypto_user_exit);
534 MODULE_LICENSE("GPL");
535 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
536 MODULE_DESCRIPTION("Crypto userspace configuration API");
537 MODULE_ALIAS("net-pf-16-proto-21");
538