xref: /linux/crypto/crypto_user.c (revision b6ebbac51bedf9e98e837688bc838f400196da5e) 
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 #include <crypto/kpp.h>
32 
33 #include "internal.h"
34 
35 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
36 
37 static DEFINE_MUTEX(crypto_cfg_mutex);
38 
39 /* The crypto netlink socket */
40 static struct sock *crypto_nlsk;
41 
42 struct crypto_dump_info {
43 	struct sk_buff *in_skb;
44 	struct sk_buff *out_skb;
45 	u32 nlmsg_seq;
46 	u16 nlmsg_flags;
47 };
48 
49 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
50 {
51 	struct crypto_alg *q, *alg = NULL;
52 
53 	down_read(&crypto_alg_sem);
54 
55 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
56 		int match = 0;
57 
58 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
59 			continue;
60 
61 		if (strlen(p->cru_driver_name))
62 			match = !strcmp(q->cra_driver_name,
63 					p->cru_driver_name);
64 		else if (!exact)
65 			match = !strcmp(q->cra_name, p->cru_name);
66 
67 		if (!match)
68 			continue;
69 
70 		if (unlikely(!crypto_mod_get(q)))
71 			continue;
72 
73 		alg = q;
74 		break;
75 	}
76 
77 	up_read(&crypto_alg_sem);
78 
79 	return alg;
80 }
81 
82 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
83 {
84 	struct crypto_report_cipher rcipher;
85 
86 	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
87 
88 	rcipher.blocksize = alg->cra_blocksize;
89 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
90 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
91 
92 	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
93 		    sizeof(struct crypto_report_cipher), &rcipher))
94 		goto nla_put_failure;
95 	return 0;
96 
97 nla_put_failure:
98 	return -EMSGSIZE;
99 }
100 
101 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
102 {
103 	struct crypto_report_comp rcomp;
104 
105 	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
106 	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
107 		    sizeof(struct crypto_report_comp), &rcomp))
108 		goto nla_put_failure;
109 	return 0;
110 
111 nla_put_failure:
112 	return -EMSGSIZE;
113 }
114 
115 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
116 {
117 	struct crypto_report_akcipher rakcipher;
118 
119 	strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
120 
121 	if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
122 		    sizeof(struct crypto_report_akcipher), &rakcipher))
123 		goto nla_put_failure;
124 	return 0;
125 
126 nla_put_failure:
127 	return -EMSGSIZE;
128 }
129 
130 static int crypto_report_kpp(struct sk_buff *skb, struct crypto_alg *alg)
131 {
132 	struct crypto_report_kpp rkpp;
133 
134 	strncpy(rkpp.type, "kpp", sizeof(rkpp.type));
135 
136 	if (nla_put(skb, CRYPTOCFGA_REPORT_KPP,
137 		    sizeof(struct crypto_report_kpp), &rkpp))
138 		goto nla_put_failure;
139 	return 0;
140 
141 nla_put_failure:
142 	return -EMSGSIZE;
143 }
144 
145 static int crypto_report_one(struct crypto_alg *alg,
146 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
147 {
148 	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
149 	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
150 		sizeof(ualg->cru_driver_name));
151 	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
152 		sizeof(ualg->cru_module_name));
153 
154 	ualg->cru_type = 0;
155 	ualg->cru_mask = 0;
156 	ualg->cru_flags = alg->cra_flags;
157 	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
158 
159 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
160 		goto nla_put_failure;
161 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
162 		struct crypto_report_larval rl;
163 
164 		strncpy(rl.type, "larval", sizeof(rl.type));
165 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
166 			    sizeof(struct crypto_report_larval), &rl))
167 			goto nla_put_failure;
168 		goto out;
169 	}
170 
171 	if (alg->cra_type && alg->cra_type->report) {
172 		if (alg->cra_type->report(skb, alg))
173 			goto nla_put_failure;
174 
175 		goto out;
176 	}
177 
178 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
179 	case CRYPTO_ALG_TYPE_CIPHER:
180 		if (crypto_report_cipher(skb, alg))
181 			goto nla_put_failure;
182 
183 		break;
184 	case CRYPTO_ALG_TYPE_COMPRESS:
185 		if (crypto_report_comp(skb, alg))
186 			goto nla_put_failure;
187 
188 		break;
189 
190 	case CRYPTO_ALG_TYPE_AKCIPHER:
191 		if (crypto_report_akcipher(skb, alg))
192 			goto nla_put_failure;
193 
194 		break;
195 	case CRYPTO_ALG_TYPE_KPP:
196 		if (crypto_report_kpp(skb, alg))
197 			goto nla_put_failure;
198 		break;
199 	}
200 
201 out:
202 	return 0;
203 
204 nla_put_failure:
205 	return -EMSGSIZE;
206 }
207 
208 static int crypto_report_alg(struct crypto_alg *alg,
209 			     struct crypto_dump_info *info)
210 {
211 	struct sk_buff *in_skb = info->in_skb;
212 	struct sk_buff *skb = info->out_skb;
213 	struct nlmsghdr *nlh;
214 	struct crypto_user_alg *ualg;
215 	int err = 0;
216 
217 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
218 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
219 	if (!nlh) {
220 		err = -EMSGSIZE;
221 		goto out;
222 	}
223 
224 	ualg = nlmsg_data(nlh);
225 
226 	err = crypto_report_one(alg, ualg, skb);
227 	if (err) {
228 		nlmsg_cancel(skb, nlh);
229 		goto out;
230 	}
231 
232 	nlmsg_end(skb, nlh);
233 
234 out:
235 	return err;
236 }
237 
238 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
239 			 struct nlattr **attrs)
240 {
241 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
242 	struct crypto_alg *alg;
243 	struct sk_buff *skb;
244 	struct crypto_dump_info info;
245 	int err;
246 
247 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
248 		return -EINVAL;
249 
250 	alg = crypto_alg_match(p, 0);
251 	if (!alg)
252 		return -ENOENT;
253 
254 	err = -ENOMEM;
255 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
256 	if (!skb)
257 		goto drop_alg;
258 
259 	info.in_skb = in_skb;
260 	info.out_skb = skb;
261 	info.nlmsg_seq = in_nlh->nlmsg_seq;
262 	info.nlmsg_flags = 0;
263 
264 	err = crypto_report_alg(alg, &info);
265 
266 drop_alg:
267 	crypto_mod_put(alg);
268 
269 	if (err)
270 		return err;
271 
272 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
273 }
274 
275 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
276 {
277 	struct crypto_alg *alg;
278 	struct crypto_dump_info info;
279 	int err;
280 
281 	if (cb->args[0])
282 		goto out;
283 
284 	cb->args[0] = 1;
285 
286 	info.in_skb = cb->skb;
287 	info.out_skb = skb;
288 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
289 	info.nlmsg_flags = NLM_F_MULTI;
290 
291 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
292 		err = crypto_report_alg(alg, &info);
293 		if (err)
294 			goto out_err;
295 	}
296 
297 out:
298 	return skb->len;
299 out_err:
300 	return err;
301 }
302 
303 static int crypto_dump_report_done(struct netlink_callback *cb)
304 {
305 	return 0;
306 }
307 
308 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
309 			     struct nlattr **attrs)
310 {
311 	struct crypto_alg *alg;
312 	struct crypto_user_alg *p = nlmsg_data(nlh);
313 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
314 	LIST_HEAD(list);
315 
316 	if (!netlink_capable(skb, CAP_NET_ADMIN))
317 		return -EPERM;
318 
319 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
320 		return -EINVAL;
321 
322 	if (priority && !strlen(p->cru_driver_name))
323 		return -EINVAL;
324 
325 	alg = crypto_alg_match(p, 1);
326 	if (!alg)
327 		return -ENOENT;
328 
329 	down_write(&crypto_alg_sem);
330 
331 	crypto_remove_spawns(alg, &list, NULL);
332 
333 	if (priority)
334 		alg->cra_priority = nla_get_u32(priority);
335 
336 	up_write(&crypto_alg_sem);
337 
338 	crypto_mod_put(alg);
339 	crypto_remove_final(&list);
340 
341 	return 0;
342 }
343 
344 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
345 			  struct nlattr **attrs)
346 {
347 	struct crypto_alg *alg;
348 	struct crypto_user_alg *p = nlmsg_data(nlh);
349 	int err;
350 
351 	if (!netlink_capable(skb, CAP_NET_ADMIN))
352 		return -EPERM;
353 
354 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
355 		return -EINVAL;
356 
357 	alg = crypto_alg_match(p, 1);
358 	if (!alg)
359 		return -ENOENT;
360 
361 	/* We can not unregister core algorithms such as aes-generic.
362 	 * We would loose the reference in the crypto_alg_list to this algorithm
363 	 * if we try to unregister. Unregistering such an algorithm without
364 	 * removing the module is not possible, so we restrict to crypto
365 	 * instances that are build from templates. */
366 	err = -EINVAL;
367 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
368 		goto drop_alg;
369 
370 	err = -EBUSY;
371 	if (atomic_read(&alg->cra_refcnt) > 2)
372 		goto drop_alg;
373 
374 	err = crypto_unregister_instance((struct crypto_instance *)alg);
375 
376 drop_alg:
377 	crypto_mod_put(alg);
378 	return err;
379 }
380 
381 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
382 			  struct nlattr **attrs)
383 {
384 	int exact = 0;
385 	const char *name;
386 	struct crypto_alg *alg;
387 	struct crypto_user_alg *p = nlmsg_data(nlh);
388 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
389 
390 	if (!netlink_capable(skb, CAP_NET_ADMIN))
391 		return -EPERM;
392 
393 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
394 		return -EINVAL;
395 
396 	if (strlen(p->cru_driver_name))
397 		exact = 1;
398 
399 	if (priority && !exact)
400 		return -EINVAL;
401 
402 	alg = crypto_alg_match(p, exact);
403 	if (alg) {
404 		crypto_mod_put(alg);
405 		return -EEXIST;
406 	}
407 
408 	if (strlen(p->cru_driver_name))
409 		name = p->cru_driver_name;
410 	else
411 		name = p->cru_name;
412 
413 	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
414 	if (IS_ERR(alg))
415 		return PTR_ERR(alg);
416 
417 	down_write(&crypto_alg_sem);
418 
419 	if (priority)
420 		alg->cra_priority = nla_get_u32(priority);
421 
422 	up_write(&crypto_alg_sem);
423 
424 	crypto_mod_put(alg);
425 
426 	return 0;
427 }
428 
429 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
430 			  struct nlattr **attrs)
431 {
432 	if (!netlink_capable(skb, CAP_NET_ADMIN))
433 		return -EPERM;
434 	return crypto_del_default_rng();
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 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
445 };
446 
447 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
448 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
449 };
450 
451 #undef MSGSIZE
452 
453 static const struct crypto_link {
454 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
455 	int (*dump)(struct sk_buff *, struct netlink_callback *);
456 	int (*done)(struct netlink_callback *);
457 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
458 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
459 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
460 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
461 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
462 						       .dump = crypto_dump_report,
463 						       .done = crypto_dump_report_done},
464 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
465 };
466 
467 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
468 {
469 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
470 	const struct crypto_link *link;
471 	int type, err;
472 
473 	type = nlh->nlmsg_type;
474 	if (type > CRYPTO_MSG_MAX)
475 		return -EINVAL;
476 
477 	type -= CRYPTO_MSG_BASE;
478 	link = &crypto_dispatch[type];
479 
480 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
481 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
482 		struct crypto_alg *alg;
483 		u16 dump_alloc = 0;
484 
485 		if (link->dump == NULL)
486 			return -EINVAL;
487 
488 		down_read(&crypto_alg_sem);
489 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
490 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
491 
492 		{
493 			struct netlink_dump_control c = {
494 				.dump = link->dump,
495 				.done = link->done,
496 				.min_dump_alloc = dump_alloc,
497 			};
498 			err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
499 		}
500 		up_read(&crypto_alg_sem);
501 
502 		return err;
503 	}
504 
505 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
506 			  crypto_policy);
507 	if (err < 0)
508 		return err;
509 
510 	if (link->doit == NULL)
511 		return -EINVAL;
512 
513 	return link->doit(skb, nlh, attrs);
514 }
515 
516 static void crypto_netlink_rcv(struct sk_buff *skb)
517 {
518 	mutex_lock(&crypto_cfg_mutex);
519 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
520 	mutex_unlock(&crypto_cfg_mutex);
521 }
522 
523 static int __init crypto_user_init(void)
524 {
525 	struct netlink_kernel_cfg cfg = {
526 		.input	= crypto_netlink_rcv,
527 	};
528 
529 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
530 	if (!crypto_nlsk)
531 		return -ENOMEM;
532 
533 	return 0;
534 }
535 
536 static void __exit crypto_user_exit(void)
537 {
538 	netlink_kernel_release(crypto_nlsk);
539 }
540 
541 module_init(crypto_user_init);
542 module_exit(crypto_user_exit);
543 MODULE_LICENSE("GPL");
544 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
545 MODULE_DESCRIPTION("Crypto userspace configuration API");
546 MODULE_ALIAS("net-pf-16-proto-21");
547