xref: /linux/crypto/crypto_user.c (revision 6315d93541f8a5f77c5ef5c4f25233e66d189603) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Crypto user configuration API.
4  *
5  * Copyright (C) 2011 secunet Security Networks AG
6  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
7  */
8 
9 #include <linux/module.h>
10 #include <linux/crypto.h>
11 #include <linux/cryptouser.h>
12 #include <linux/sched.h>
13 #include <linux/security.h>
14 #include <net/netlink.h>
15 #include <net/net_namespace.h>
16 #include <net/sock.h>
17 #include <crypto/internal/skcipher.h>
18 #include <crypto/internal/rng.h>
19 #include <crypto/akcipher.h>
20 #include <crypto/kpp.h>
21 
22 #include "internal.h"
23 
24 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
25 
26 static DEFINE_MUTEX(crypto_cfg_mutex);
27 
28 struct crypto_dump_info {
29 	struct sk_buff *in_skb;
30 	struct sk_buff *out_skb;
31 	u32 nlmsg_seq;
32 	u16 nlmsg_flags;
33 };
34 
35 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
36 {
37 	struct crypto_alg *q, *alg = NULL;
38 
39 	down_read(&crypto_alg_sem);
40 
41 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
42 		int match = 0;
43 
44 		if (crypto_is_larval(q))
45 			continue;
46 
47 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
48 			continue;
49 
50 		if (strlen(p->cru_driver_name))
51 			match = !strcmp(q->cra_driver_name,
52 					p->cru_driver_name);
53 		else if (!exact)
54 			match = !strcmp(q->cra_name, p->cru_name);
55 
56 		if (!match)
57 			continue;
58 
59 		if (unlikely(!crypto_mod_get(q)))
60 			continue;
61 
62 		alg = q;
63 		break;
64 	}
65 
66 	up_read(&crypto_alg_sem);
67 
68 	return alg;
69 }
70 
71 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
72 {
73 	struct crypto_report_cipher rcipher;
74 
75 	memset(&rcipher, 0, sizeof(rcipher));
76 
77 	strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
78 
79 	rcipher.blocksize = alg->cra_blocksize;
80 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
81 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
82 
83 	return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
84 		       sizeof(rcipher), &rcipher);
85 }
86 
87 static int crypto_report_one(struct crypto_alg *alg,
88 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
89 {
90 	memset(ualg, 0, sizeof(*ualg));
91 
92 	strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
93 	strscpy(ualg->cru_driver_name, alg->cra_driver_name,
94 		sizeof(ualg->cru_driver_name));
95 	strscpy(ualg->cru_module_name, module_name(alg->cra_module),
96 		sizeof(ualg->cru_module_name));
97 
98 	ualg->cru_type = 0;
99 	ualg->cru_mask = 0;
100 	ualg->cru_flags = alg->cra_flags;
101 	ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
102 
103 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
104 		goto nla_put_failure;
105 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
106 		struct crypto_report_larval rl;
107 
108 		memset(&rl, 0, sizeof(rl));
109 		strscpy(rl.type, "larval", sizeof(rl.type));
110 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
111 			goto nla_put_failure;
112 		goto out;
113 	}
114 
115 	if (alg->cra_type && alg->cra_type->report) {
116 		if (alg->cra_type->report(skb, alg))
117 			goto nla_put_failure;
118 
119 		goto out;
120 	}
121 
122 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
123 	case CRYPTO_ALG_TYPE_CIPHER:
124 		if (crypto_report_cipher(skb, alg))
125 			goto nla_put_failure;
126 
127 		break;
128 	}
129 
130 out:
131 	return 0;
132 
133 nla_put_failure:
134 	return -EMSGSIZE;
135 }
136 
137 static int crypto_report_alg(struct crypto_alg *alg,
138 			     struct crypto_dump_info *info)
139 {
140 	struct sk_buff *in_skb = info->in_skb;
141 	struct sk_buff *skb = info->out_skb;
142 	struct nlmsghdr *nlh;
143 	struct crypto_user_alg *ualg;
144 	int err = 0;
145 
146 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
147 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
148 	if (!nlh) {
149 		err = -EMSGSIZE;
150 		goto out;
151 	}
152 
153 	ualg = nlmsg_data(nlh);
154 
155 	err = crypto_report_one(alg, ualg, skb);
156 	if (err) {
157 		nlmsg_cancel(skb, nlh);
158 		goto out;
159 	}
160 
161 	nlmsg_end(skb, nlh);
162 
163 out:
164 	return err;
165 }
166 
167 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
168 			 struct nlattr **attrs)
169 {
170 	struct net *net = sock_net(in_skb->sk);
171 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
172 	struct crypto_alg *alg;
173 	struct sk_buff *skb;
174 	struct crypto_dump_info info;
175 	int err;
176 
177 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
178 		return -EINVAL;
179 
180 	alg = crypto_alg_match(p, 0);
181 	if (!alg)
182 		return -ENOENT;
183 
184 	err = -ENOMEM;
185 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
186 	if (!skb)
187 		goto drop_alg;
188 
189 	info.in_skb = in_skb;
190 	info.out_skb = skb;
191 	info.nlmsg_seq = in_nlh->nlmsg_seq;
192 	info.nlmsg_flags = 0;
193 
194 	err = crypto_report_alg(alg, &info);
195 
196 drop_alg:
197 	crypto_mod_put(alg);
198 
199 	if (err) {
200 		kfree_skb(skb);
201 		return err;
202 	}
203 
204 	return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
205 }
206 
207 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
208 {
209 	const size_t start_pos = cb->args[0];
210 	size_t pos = 0;
211 	struct crypto_dump_info info;
212 	struct crypto_alg *alg;
213 	int res;
214 
215 	info.in_skb = cb->skb;
216 	info.out_skb = skb;
217 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
218 	info.nlmsg_flags = NLM_F_MULTI;
219 
220 	down_read(&crypto_alg_sem);
221 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
222 		if (pos >= start_pos) {
223 			res = crypto_report_alg(alg, &info);
224 			if (res == -EMSGSIZE)
225 				break;
226 			if (res)
227 				goto out;
228 		}
229 		pos++;
230 	}
231 	cb->args[0] = pos;
232 	res = skb->len;
233 out:
234 	up_read(&crypto_alg_sem);
235 	return res;
236 }
237 
238 static int crypto_dump_report_done(struct netlink_callback *cb)
239 {
240 	return 0;
241 }
242 
243 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
244 			     struct nlattr **attrs)
245 {
246 	struct crypto_alg *alg;
247 	struct crypto_user_alg *p = nlmsg_data(nlh);
248 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
249 	LIST_HEAD(list);
250 
251 	if (!netlink_capable(skb, CAP_NET_ADMIN))
252 		return -EPERM;
253 
254 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
255 		return -EINVAL;
256 
257 	if (priority && !strlen(p->cru_driver_name))
258 		return -EINVAL;
259 
260 	alg = crypto_alg_match(p, 1);
261 	if (!alg)
262 		return -ENOENT;
263 
264 	down_write(&crypto_alg_sem);
265 
266 	crypto_remove_spawns(alg, &list, NULL);
267 
268 	if (priority)
269 		alg->cra_priority = nla_get_u32(priority);
270 
271 	up_write(&crypto_alg_sem);
272 
273 	crypto_mod_put(alg);
274 	crypto_remove_final(&list);
275 
276 	return 0;
277 }
278 
279 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
280 			  struct nlattr **attrs)
281 {
282 	struct crypto_alg *alg;
283 	struct crypto_user_alg *p = nlmsg_data(nlh);
284 	int err;
285 
286 	if (!netlink_capable(skb, CAP_NET_ADMIN))
287 		return -EPERM;
288 
289 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
290 		return -EINVAL;
291 
292 	alg = crypto_alg_match(p, 1);
293 	if (!alg)
294 		return -ENOENT;
295 
296 	/* We can not unregister core algorithms such as aes-generic.
297 	 * We would loose the reference in the crypto_alg_list to this algorithm
298 	 * if we try to unregister. Unregistering such an algorithm without
299 	 * removing the module is not possible, so we restrict to crypto
300 	 * instances that are build from templates. */
301 	err = -EINVAL;
302 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
303 		goto drop_alg;
304 
305 	err = -EBUSY;
306 	if (refcount_read(&alg->cra_refcnt) > 2)
307 		goto drop_alg;
308 
309 	crypto_unregister_instance((struct crypto_instance *)alg);
310 	err = 0;
311 
312 drop_alg:
313 	crypto_mod_put(alg);
314 	return err;
315 }
316 
317 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
318 			  struct nlattr **attrs)
319 {
320 	int exact = 0;
321 	const char *name;
322 	struct crypto_alg *alg;
323 	struct crypto_user_alg *p = nlmsg_data(nlh);
324 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
325 
326 	if (!netlink_capable(skb, CAP_NET_ADMIN))
327 		return -EPERM;
328 
329 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
330 		return -EINVAL;
331 
332 	if (strlen(p->cru_driver_name))
333 		exact = 1;
334 
335 	if (priority && !exact)
336 		return -EINVAL;
337 
338 	alg = crypto_alg_match(p, exact);
339 	if (alg) {
340 		crypto_mod_put(alg);
341 		return -EEXIST;
342 	}
343 
344 	if (strlen(p->cru_driver_name))
345 		name = p->cru_driver_name;
346 	else
347 		name = p->cru_name;
348 
349 	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
350 	if (IS_ERR(alg))
351 		return PTR_ERR(alg);
352 
353 	down_write(&crypto_alg_sem);
354 
355 	if (priority)
356 		alg->cra_priority = nla_get_u32(priority);
357 
358 	up_write(&crypto_alg_sem);
359 
360 	crypto_mod_put(alg);
361 
362 	return 0;
363 }
364 
365 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
366 			  struct nlattr **attrs)
367 {
368 	if (!netlink_capable(skb, CAP_NET_ADMIN))
369 		return -EPERM;
370 	return crypto_del_default_rng();
371 }
372 
373 static int crypto_reportstat(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
374 			     struct nlattr **attrs)
375 {
376 	/* No longer supported */
377 	return -ENOTSUPP;
378 }
379 
380 #define MSGSIZE(type) sizeof(struct type)
381 
382 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
383 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
384 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
385 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
386 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
387 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
388 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
389 };
390 
391 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
392 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
393 };
394 
395 #undef MSGSIZE
396 
397 static const struct crypto_link {
398 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
399 	int (*dump)(struct sk_buff *, struct netlink_callback *);
400 	int (*done)(struct netlink_callback *);
401 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
402 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
403 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
404 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
405 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
406 						       .dump = crypto_dump_report,
407 						       .done = crypto_dump_report_done},
408 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
409 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
410 };
411 
412 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
413 			       struct netlink_ext_ack *extack)
414 {
415 	struct net *net = sock_net(skb->sk);
416 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
417 	const struct crypto_link *link;
418 	int type, err;
419 
420 	type = nlh->nlmsg_type;
421 	if (type > CRYPTO_MSG_MAX)
422 		return -EINVAL;
423 
424 	type -= CRYPTO_MSG_BASE;
425 	link = &crypto_dispatch[type];
426 
427 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
428 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
429 		struct crypto_alg *alg;
430 		unsigned long dump_alloc = 0;
431 
432 		if (link->dump == NULL)
433 			return -EINVAL;
434 
435 		down_read(&crypto_alg_sem);
436 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
437 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
438 		up_read(&crypto_alg_sem);
439 
440 		{
441 			struct netlink_dump_control c = {
442 				.dump = link->dump,
443 				.done = link->done,
444 				.min_dump_alloc = min(dump_alloc, 65535UL),
445 			};
446 			err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
447 		}
448 
449 		return err;
450 	}
451 
452 	err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
453 				     CRYPTOCFGA_MAX, crypto_policy, extack);
454 	if (err < 0)
455 		return err;
456 
457 	if (link->doit == NULL)
458 		return -EINVAL;
459 
460 	return link->doit(skb, nlh, attrs);
461 }
462 
463 static void crypto_netlink_rcv(struct sk_buff *skb)
464 {
465 	mutex_lock(&crypto_cfg_mutex);
466 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
467 	mutex_unlock(&crypto_cfg_mutex);
468 }
469 
470 static int __net_init crypto_netlink_init(struct net *net)
471 {
472 	struct netlink_kernel_cfg cfg = {
473 		.input	= crypto_netlink_rcv,
474 	};
475 
476 	net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
477 	return net->crypto_nlsk == NULL ? -ENOMEM : 0;
478 }
479 
480 static void __net_exit crypto_netlink_exit(struct net *net)
481 {
482 	netlink_kernel_release(net->crypto_nlsk);
483 	net->crypto_nlsk = NULL;
484 }
485 
486 static struct pernet_operations crypto_netlink_net_ops = {
487 	.init = crypto_netlink_init,
488 	.exit = crypto_netlink_exit,
489 };
490 
491 static int __init crypto_user_init(void)
492 {
493 	return register_pernet_subsys(&crypto_netlink_net_ops);
494 }
495 
496 static void __exit crypto_user_exit(void)
497 {
498 	unregister_pernet_subsys(&crypto_netlink_net_ops);
499 }
500 
501 module_init(crypto_user_init);
502 module_exit(crypto_user_exit);
503 MODULE_LICENSE("GPL");
504 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
505 MODULE_DESCRIPTION("Crypto userspace configuration API");
506 MODULE_ALIAS("net-pf-16-proto-21");
507