xref: /openbmc/linux/crypto/crypto_user_base.c (revision 5a158981) 
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 #include <crypto/internal/cryptouser.h>
22 
23 #include "internal.h"
24 
25 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
26 
27 static DEFINE_MUTEX(crypto_cfg_mutex);
28 
29 struct crypto_dump_info {
30 	struct sk_buff *in_skb;
31 	struct sk_buff *out_skb;
32 	u32 nlmsg_seq;
33 	u16 nlmsg_flags;
34 };
35 
36 struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
37 {
38 	struct crypto_alg *q, *alg = NULL;
39 
40 	down_read(&crypto_alg_sem);
41 
42 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
43 		int match = 0;
44 
45 		if (crypto_is_larval(q))
46 			continue;
47 
48 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
49 			continue;
50 
51 		if (strlen(p->cru_driver_name))
52 			match = !strcmp(q->cra_driver_name,
53 					p->cru_driver_name);
54 		else if (!exact)
55 			match = !strcmp(q->cra_name, p->cru_name);
56 
57 		if (!match)
58 			continue;
59 
60 		if (unlikely(!crypto_mod_get(q)))
61 			continue;
62 
63 		alg = q;
64 		break;
65 	}
66 
67 	up_read(&crypto_alg_sem);
68 
69 	return alg;
70 }
71 
72 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
73 {
74 	struct crypto_report_cipher rcipher;
75 
76 	memset(&rcipher, 0, sizeof(rcipher));
77 
78 	strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
79 
80 	rcipher.blocksize = alg->cra_blocksize;
81 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
82 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
83 
84 	return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
85 		       sizeof(rcipher), &rcipher);
86 }
87 
88 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
89 {
90 	struct crypto_report_comp rcomp;
91 
92 	memset(&rcomp, 0, sizeof(rcomp));
93 
94 	strscpy(rcomp.type, "compression", sizeof(rcomp.type));
95 
96 	return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
97 }
98 
99 static int crypto_report_one(struct crypto_alg *alg,
100 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
101 {
102 	memset(ualg, 0, sizeof(*ualg));
103 
104 	strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
105 	strscpy(ualg->cru_driver_name, alg->cra_driver_name,
106 		sizeof(ualg->cru_driver_name));
107 	strscpy(ualg->cru_module_name, module_name(alg->cra_module),
108 		sizeof(ualg->cru_module_name));
109 
110 	ualg->cru_type = 0;
111 	ualg->cru_mask = 0;
112 	ualg->cru_flags = alg->cra_flags;
113 	ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
114 
115 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
116 		goto nla_put_failure;
117 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
118 		struct crypto_report_larval rl;
119 
120 		memset(&rl, 0, sizeof(rl));
121 		strscpy(rl.type, "larval", sizeof(rl.type));
122 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
123 			goto nla_put_failure;
124 		goto out;
125 	}
126 
127 	if (alg->cra_type && alg->cra_type->report) {
128 		if (alg->cra_type->report(skb, alg))
129 			goto nla_put_failure;
130 
131 		goto out;
132 	}
133 
134 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
135 	case CRYPTO_ALG_TYPE_CIPHER:
136 		if (crypto_report_cipher(skb, alg))
137 			goto nla_put_failure;
138 
139 		break;
140 	case CRYPTO_ALG_TYPE_COMPRESS:
141 		if (crypto_report_comp(skb, alg))
142 			goto nla_put_failure;
143 
144 		break;
145 	}
146 
147 out:
148 	return 0;
149 
150 nla_put_failure:
151 	return -EMSGSIZE;
152 }
153 
154 static int crypto_report_alg(struct crypto_alg *alg,
155 			     struct crypto_dump_info *info)
156 {
157 	struct sk_buff *in_skb = info->in_skb;
158 	struct sk_buff *skb = info->out_skb;
159 	struct nlmsghdr *nlh;
160 	struct crypto_user_alg *ualg;
161 	int err = 0;
162 
163 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
164 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
165 	if (!nlh) {
166 		err = -EMSGSIZE;
167 		goto out;
168 	}
169 
170 	ualg = nlmsg_data(nlh);
171 
172 	err = crypto_report_one(alg, ualg, skb);
173 	if (err) {
174 		nlmsg_cancel(skb, nlh);
175 		goto out;
176 	}
177 
178 	nlmsg_end(skb, nlh);
179 
180 out:
181 	return err;
182 }
183 
184 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
185 			 struct nlattr **attrs)
186 {
187 	struct net *net = sock_net(in_skb->sk);
188 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
189 	struct crypto_alg *alg;
190 	struct sk_buff *skb;
191 	struct crypto_dump_info info;
192 	int err;
193 
194 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
195 		return -EINVAL;
196 
197 	alg = crypto_alg_match(p, 0);
198 	if (!alg)
199 		return -ENOENT;
200 
201 	err = -ENOMEM;
202 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
203 	if (!skb)
204 		goto drop_alg;
205 
206 	info.in_skb = in_skb;
207 	info.out_skb = skb;
208 	info.nlmsg_seq = in_nlh->nlmsg_seq;
209 	info.nlmsg_flags = 0;
210 
211 	err = crypto_report_alg(alg, &info);
212 
213 drop_alg:
214 	crypto_mod_put(alg);
215 
216 	if (err) {
217 		kfree_skb(skb);
218 		return err;
219 	}
220 
221 	return nlmsg_unicast(net->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 	const size_t start_pos = cb->args[0];
227 	size_t pos = 0;
228 	struct crypto_dump_info info;
229 	struct crypto_alg *alg;
230 	int res;
231 
232 	info.in_skb = cb->skb;
233 	info.out_skb = skb;
234 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
235 	info.nlmsg_flags = NLM_F_MULTI;
236 
237 	down_read(&crypto_alg_sem);
238 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
239 		if (pos >= start_pos) {
240 			res = crypto_report_alg(alg, &info);
241 			if (res == -EMSGSIZE)
242 				break;
243 			if (res)
244 				goto out;
245 		}
246 		pos++;
247 	}
248 	cb->args[0] = pos;
249 	res = skb->len;
250 out:
251 	up_read(&crypto_alg_sem);
252 	return res;
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_mod_put(alg);
291 	crypto_remove_final(&list);
292 
293 	return 0;
294 }
295 
296 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
297 			  struct nlattr **attrs)
298 {
299 	struct crypto_alg *alg;
300 	struct crypto_user_alg *p = nlmsg_data(nlh);
301 	int err;
302 
303 	if (!netlink_capable(skb, CAP_NET_ADMIN))
304 		return -EPERM;
305 
306 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
307 		return -EINVAL;
308 
309 	alg = crypto_alg_match(p, 1);
310 	if (!alg)
311 		return -ENOENT;
312 
313 	/* We can not unregister core algorithms such as aes-generic.
314 	 * We would loose the reference in the crypto_alg_list to this algorithm
315 	 * if we try to unregister. Unregistering such an algorithm without
316 	 * removing the module is not possible, so we restrict to crypto
317 	 * instances that are build from templates. */
318 	err = -EINVAL;
319 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
320 		goto drop_alg;
321 
322 	err = -EBUSY;
323 	if (refcount_read(&alg->cra_refcnt) > 2)
324 		goto drop_alg;
325 
326 	err = crypto_unregister_instance((struct crypto_instance *)alg);
327 
328 drop_alg:
329 	crypto_mod_put(alg);
330 	return err;
331 }
332 
333 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
334 			  struct nlattr **attrs)
335 {
336 	int exact = 0;
337 	const char *name;
338 	struct crypto_alg *alg;
339 	struct crypto_user_alg *p = nlmsg_data(nlh);
340 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
341 
342 	if (!netlink_capable(skb, CAP_NET_ADMIN))
343 		return -EPERM;
344 
345 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
346 		return -EINVAL;
347 
348 	if (strlen(p->cru_driver_name))
349 		exact = 1;
350 
351 	if (priority && !exact)
352 		return -EINVAL;
353 
354 	alg = crypto_alg_match(p, exact);
355 	if (alg) {
356 		crypto_mod_put(alg);
357 		return -EEXIST;
358 	}
359 
360 	if (strlen(p->cru_driver_name))
361 		name = p->cru_driver_name;
362 	else
363 		name = p->cru_name;
364 
365 	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
366 	if (IS_ERR(alg))
367 		return PTR_ERR(alg);
368 
369 	down_write(&crypto_alg_sem);
370 
371 	if (priority)
372 		alg->cra_priority = nla_get_u32(priority);
373 
374 	up_write(&crypto_alg_sem);
375 
376 	crypto_mod_put(alg);
377 
378 	return 0;
379 }
380 
381 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
382 			  struct nlattr **attrs)
383 {
384 	if (!netlink_capable(skb, CAP_NET_ADMIN))
385 		return -EPERM;
386 	return crypto_del_default_rng();
387 }
388 
389 #define MSGSIZE(type) sizeof(struct type)
390 
391 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
392 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
393 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
394 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
395 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
396 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
397 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
398 };
399 
400 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
401 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
402 };
403 
404 #undef MSGSIZE
405 
406 static const struct crypto_link {
407 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
408 	int (*dump)(struct sk_buff *, struct netlink_callback *);
409 	int (*done)(struct netlink_callback *);
410 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
411 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
412 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
413 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
414 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
415 						       .dump = crypto_dump_report,
416 						       .done = crypto_dump_report_done},
417 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
418 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
419 };
420 
421 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
422 			       struct netlink_ext_ack *extack)
423 {
424 	struct net *net = sock_net(skb->sk);
425 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
426 	const struct crypto_link *link;
427 	int type, err;
428 
429 	type = nlh->nlmsg_type;
430 	if (type > CRYPTO_MSG_MAX)
431 		return -EINVAL;
432 
433 	type -= CRYPTO_MSG_BASE;
434 	link = &crypto_dispatch[type];
435 
436 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
437 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
438 		struct crypto_alg *alg;
439 		unsigned long dump_alloc = 0;
440 
441 		if (link->dump == NULL)
442 			return -EINVAL;
443 
444 		down_read(&crypto_alg_sem);
445 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
446 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
447 		up_read(&crypto_alg_sem);
448 
449 		{
450 			struct netlink_dump_control c = {
451 				.dump = link->dump,
452 				.done = link->done,
453 				.min_dump_alloc = min(dump_alloc, 65535UL),
454 			};
455 			err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
456 		}
457 
458 		return err;
459 	}
460 
461 	err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
462 				     CRYPTOCFGA_MAX, crypto_policy, extack);
463 	if (err < 0)
464 		return err;
465 
466 	if (link->doit == NULL)
467 		return -EINVAL;
468 
469 	return link->doit(skb, nlh, attrs);
470 }
471 
472 static void crypto_netlink_rcv(struct sk_buff *skb)
473 {
474 	mutex_lock(&crypto_cfg_mutex);
475 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
476 	mutex_unlock(&crypto_cfg_mutex);
477 }
478 
479 static int __net_init crypto_netlink_init(struct net *net)
480 {
481 	struct netlink_kernel_cfg cfg = {
482 		.input	= crypto_netlink_rcv,
483 	};
484 
485 	net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
486 	return net->crypto_nlsk == NULL ? -ENOMEM : 0;
487 }
488 
489 static void __net_exit crypto_netlink_exit(struct net *net)
490 {
491 	netlink_kernel_release(net->crypto_nlsk);
492 	net->crypto_nlsk = NULL;
493 }
494 
495 static struct pernet_operations crypto_netlink_net_ops = {
496 	.init = crypto_netlink_init,
497 	.exit = crypto_netlink_exit,
498 };
499 
500 static int __init crypto_user_init(void)
501 {
502 	return register_pernet_subsys(&crypto_netlink_net_ops);
503 }
504 
505 static void __exit crypto_user_exit(void)
506 {
507 	unregister_pernet_subsys(&crypto_netlink_net_ops);
508 }
509 
510 module_init(crypto_user_init);
511 module_exit(crypto_user_exit);
512 MODULE_LICENSE("GPL");
513 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
514 MODULE_DESCRIPTION("Crypto userspace configuration API");
515 MODULE_ALIAS("net-pf-16-proto-21");
516