xref: /linux/crypto/crypto_user.c (revision ff5599816711d2e67da2d7561fd36ac48debd433) 
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 (!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 (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
299 		return -EINVAL;
300 
301 	alg = crypto_alg_match(p, 1);
302 	if (!alg)
303 		return -ENOENT;
304 
305 	/* We can not unregister core algorithms such as aes-generic.
306 	 * We would loose the reference in the crypto_alg_list to this algorithm
307 	 * if we try to unregister. Unregistering such an algorithm without
308 	 * removing the module is not possible, so we restrict to crypto
309 	 * instances that are build from templates. */
310 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
311 		return -EINVAL;
312 
313 	if (atomic_read(&alg->cra_refcnt) != 1)
314 		return -EBUSY;
315 
316 	return crypto_unregister_instance(alg);
317 }
318 
319 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
320 						   u32 mask)
321 {
322 	int err;
323 	struct crypto_alg *alg;
324 
325 	type = crypto_skcipher_type(type);
326 	mask = crypto_skcipher_mask(mask);
327 
328 	for (;;) {
329 		alg = crypto_lookup_skcipher(name,  type, mask);
330 		if (!IS_ERR(alg))
331 			return alg;
332 
333 		err = PTR_ERR(alg);
334 		if (err != -EAGAIN)
335 			break;
336 		if (signal_pending(current)) {
337 			err = -EINTR;
338 			break;
339 		}
340 	}
341 
342 	return ERR_PTR(err);
343 }
344 
345 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
346 					       u32 mask)
347 {
348 	int err;
349 	struct crypto_alg *alg;
350 
351 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
352 	type |= CRYPTO_ALG_TYPE_AEAD;
353 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
354 	mask |= CRYPTO_ALG_TYPE_MASK;
355 
356 	for (;;) {
357 		alg = crypto_lookup_aead(name,  type, mask);
358 		if (!IS_ERR(alg))
359 			return alg;
360 
361 		err = PTR_ERR(alg);
362 		if (err != -EAGAIN)
363 			break;
364 		if (signal_pending(current)) {
365 			err = -EINTR;
366 			break;
367 		}
368 	}
369 
370 	return ERR_PTR(err);
371 }
372 
373 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
374 			  struct nlattr **attrs)
375 {
376 	int exact = 0;
377 	const char *name;
378 	struct crypto_alg *alg;
379 	struct crypto_user_alg *p = nlmsg_data(nlh);
380 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
381 
382 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
383 		return -EINVAL;
384 
385 	if (strlen(p->cru_driver_name))
386 		exact = 1;
387 
388 	if (priority && !exact)
389 		return -EINVAL;
390 
391 	alg = crypto_alg_match(p, exact);
392 	if (alg)
393 		return -EEXIST;
394 
395 	if (strlen(p->cru_driver_name))
396 		name = p->cru_driver_name;
397 	else
398 		name = p->cru_name;
399 
400 	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
401 	case CRYPTO_ALG_TYPE_AEAD:
402 		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
403 		break;
404 	case CRYPTO_ALG_TYPE_GIVCIPHER:
405 	case CRYPTO_ALG_TYPE_BLKCIPHER:
406 	case CRYPTO_ALG_TYPE_ABLKCIPHER:
407 		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
408 		break;
409 	default:
410 		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
411 	}
412 
413 	if (IS_ERR(alg))
414 		return PTR_ERR(alg);
415 
416 	down_write(&crypto_alg_sem);
417 
418 	if (priority)
419 		alg->cra_priority = nla_get_u32(priority);
420 
421 	up_write(&crypto_alg_sem);
422 
423 	crypto_mod_put(alg);
424 
425 	return 0;
426 }
427 
428 #define MSGSIZE(type) sizeof(struct type)
429 
430 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
431 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
432 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
433 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
434 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
435 };
436 
437 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
438 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
439 };
440 
441 #undef MSGSIZE
442 
443 static const struct crypto_link {
444 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
445 	int (*dump)(struct sk_buff *, struct netlink_callback *);
446 	int (*done)(struct netlink_callback *);
447 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
448 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
449 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
450 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
451 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
452 						       .dump = crypto_dump_report,
453 						       .done = crypto_dump_report_done},
454 };
455 
456 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
457 {
458 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
459 	const struct crypto_link *link;
460 	int type, err;
461 
462 	type = nlh->nlmsg_type;
463 	if (type > CRYPTO_MSG_MAX)
464 		return -EINVAL;
465 
466 	type -= CRYPTO_MSG_BASE;
467 	link = &crypto_dispatch[type];
468 
469 	if (!capable(CAP_NET_ADMIN))
470 		return -EPERM;
471 
472 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
473 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
474 		struct crypto_alg *alg;
475 		u16 dump_alloc = 0;
476 
477 		if (link->dump == NULL)
478 			return -EINVAL;
479 
480 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
481 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
482 
483 		{
484 			struct netlink_dump_control c = {
485 				.dump = link->dump,
486 				.done = link->done,
487 				.min_dump_alloc = dump_alloc,
488 			};
489 			return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
490 		}
491 	}
492 
493 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
494 			  crypto_policy);
495 	if (err < 0)
496 		return err;
497 
498 	if (link->doit == NULL)
499 		return -EINVAL;
500 
501 	return link->doit(skb, nlh, attrs);
502 }
503 
504 static void crypto_netlink_rcv(struct sk_buff *skb)
505 {
506 	mutex_lock(&crypto_cfg_mutex);
507 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
508 	mutex_unlock(&crypto_cfg_mutex);
509 }
510 
511 static int __init crypto_user_init(void)
512 {
513 	struct netlink_kernel_cfg cfg = {
514 		.input	= crypto_netlink_rcv,
515 	};
516 
517 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
518 	if (!crypto_nlsk)
519 		return -ENOMEM;
520 
521 	return 0;
522 }
523 
524 static void __exit crypto_user_exit(void)
525 {
526 	netlink_kernel_release(crypto_nlsk);
527 }
528 
529 module_init(crypto_user_init);
530 module_exit(crypto_user_exit);
531 MODULE_LICENSE("GPL");
532 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
533 MODULE_DESCRIPTION("Crypto userspace configuration API");
534