xref: /openbmc/linux/crypto/crypto_user_base.c (revision 44ce0cd3) 
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 <net/netlink.h>
14 #include <linux/security.h>
15 #include <net/net_namespace.h>
16 #include <crypto/internal/skcipher.h>
17 #include <crypto/internal/rng.h>
18 #include <crypto/akcipher.h>
19 #include <crypto/kpp.h>
20 #include <crypto/internal/cryptouser.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 /* The crypto netlink socket */
29 struct sock *crypto_nlsk;
30 
31 struct crypto_dump_info {
32 	struct sk_buff *in_skb;
33 	struct sk_buff *out_skb;
34 	u32 nlmsg_seq;
35 	u16 nlmsg_flags;
36 };
37 
38 struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
39 {
40 	struct crypto_alg *q, *alg = NULL;
41 
42 	down_read(&crypto_alg_sem);
43 
44 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
45 		int match = 0;
46 
47 		if (crypto_is_larval(q))
48 			continue;
49 
50 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
51 			continue;
52 
53 		if (strlen(p->cru_driver_name))
54 			match = !strcmp(q->cra_driver_name,
55 					p->cru_driver_name);
56 		else if (!exact)
57 			match = !strcmp(q->cra_name, p->cru_name);
58 
59 		if (!match)
60 			continue;
61 
62 		if (unlikely(!crypto_mod_get(q)))
63 			continue;
64 
65 		alg = q;
66 		break;
67 	}
68 
69 	up_read(&crypto_alg_sem);
70 
71 	return alg;
72 }
73 
74 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
75 {
76 	struct crypto_report_cipher rcipher;
77 
78 	memset(&rcipher, 0, sizeof(rcipher));
79 
80 	strscpy(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 	return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
87 		       sizeof(rcipher), &rcipher);
88 }
89 
90 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
91 {
92 	struct crypto_report_comp rcomp;
93 
94 	memset(&rcomp, 0, sizeof(rcomp));
95 
96 	strscpy(rcomp.type, "compression", sizeof(rcomp.type));
97 
98 	return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
99 }
100 
101 static int crypto_report_one(struct crypto_alg *alg,
102 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
103 {
104 	memset(ualg, 0, sizeof(*ualg));
105 
106 	strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
107 	strscpy(ualg->cru_driver_name, alg->cra_driver_name,
108 		sizeof(ualg->cru_driver_name));
109 	strscpy(ualg->cru_module_name, module_name(alg->cra_module),
110 		sizeof(ualg->cru_module_name));
111 
112 	ualg->cru_type = 0;
113 	ualg->cru_mask = 0;
114 	ualg->cru_flags = alg->cra_flags;
115 	ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
116 
117 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
118 		goto nla_put_failure;
119 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
120 		struct crypto_report_larval rl;
121 
122 		memset(&rl, 0, sizeof(rl));
123 		strscpy(rl.type, "larval", sizeof(rl.type));
124 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
125 			goto nla_put_failure;
126 		goto out;
127 	}
128 
129 	if (alg->cra_type && alg->cra_type->report) {
130 		if (alg->cra_type->report(skb, alg))
131 			goto nla_put_failure;
132 
133 		goto out;
134 	}
135 
136 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
137 	case CRYPTO_ALG_TYPE_CIPHER:
138 		if (crypto_report_cipher(skb, alg))
139 			goto nla_put_failure;
140 
141 		break;
142 	case CRYPTO_ALG_TYPE_COMPRESS:
143 		if (crypto_report_comp(skb, alg))
144 			goto nla_put_failure;
145 
146 		break;
147 	}
148 
149 out:
150 	return 0;
151 
152 nla_put_failure:
153 	return -EMSGSIZE;
154 }
155 
156 static int crypto_report_alg(struct crypto_alg *alg,
157 			     struct crypto_dump_info *info)
158 {
159 	struct sk_buff *in_skb = info->in_skb;
160 	struct sk_buff *skb = info->out_skb;
161 	struct nlmsghdr *nlh;
162 	struct crypto_user_alg *ualg;
163 	int err = 0;
164 
165 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
166 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
167 	if (!nlh) {
168 		err = -EMSGSIZE;
169 		goto out;
170 	}
171 
172 	ualg = nlmsg_data(nlh);
173 
174 	err = crypto_report_one(alg, ualg, skb);
175 	if (err) {
176 		nlmsg_cancel(skb, nlh);
177 		goto out;
178 	}
179 
180 	nlmsg_end(skb, nlh);
181 
182 out:
183 	return err;
184 }
185 
186 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
187 			 struct nlattr **attrs)
188 {
189 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
190 	struct crypto_alg *alg;
191 	struct sk_buff *skb;
192 	struct crypto_dump_info info;
193 	int err;
194 
195 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
196 		return -EINVAL;
197 
198 	alg = crypto_alg_match(p, 0);
199 	if (!alg)
200 		return -ENOENT;
201 
202 	err = -ENOMEM;
203 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
204 	if (!skb)
205 		goto drop_alg;
206 
207 	info.in_skb = in_skb;
208 	info.out_skb = skb;
209 	info.nlmsg_seq = in_nlh->nlmsg_seq;
210 	info.nlmsg_flags = 0;
211 
212 	err = crypto_report_alg(alg, &info);
213 
214 drop_alg:
215 	crypto_mod_put(alg);
216 
217 	if (err)
218 		return err;
219 
220 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
221 }
222 
223 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
224 {
225 	const size_t start_pos = cb->args[0];
226 	size_t pos = 0;
227 	struct crypto_dump_info info;
228 	struct crypto_alg *alg;
229 	int res;
230 
231 	info.in_skb = cb->skb;
232 	info.out_skb = skb;
233 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
234 	info.nlmsg_flags = NLM_F_MULTI;
235 
236 	down_read(&crypto_alg_sem);
237 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
238 		if (pos >= start_pos) {
239 			res = crypto_report_alg(alg, &info);
240 			if (res == -EMSGSIZE)
241 				break;
242 			if (res)
243 				goto out;
244 		}
245 		pos++;
246 	}
247 	cb->args[0] = pos;
248 	res = skb->len;
249 out:
250 	up_read(&crypto_alg_sem);
251 	return res;
252 }
253 
254 static int crypto_dump_report_done(struct netlink_callback *cb)
255 {
256 	return 0;
257 }
258 
259 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
260 			     struct nlattr **attrs)
261 {
262 	struct crypto_alg *alg;
263 	struct crypto_user_alg *p = nlmsg_data(nlh);
264 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
265 	LIST_HEAD(list);
266 
267 	if (!netlink_capable(skb, CAP_NET_ADMIN))
268 		return -EPERM;
269 
270 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
271 		return -EINVAL;
272 
273 	if (priority && !strlen(p->cru_driver_name))
274 		return -EINVAL;
275 
276 	alg = crypto_alg_match(p, 1);
277 	if (!alg)
278 		return -ENOENT;
279 
280 	down_write(&crypto_alg_sem);
281 
282 	crypto_remove_spawns(alg, &list, NULL);
283 
284 	if (priority)
285 		alg->cra_priority = nla_get_u32(priority);
286 
287 	up_write(&crypto_alg_sem);
288 
289 	crypto_mod_put(alg);
290 	crypto_remove_final(&list);
291 
292 	return 0;
293 }
294 
295 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
296 			  struct nlattr **attrs)
297 {
298 	struct crypto_alg *alg;
299 	struct crypto_user_alg *p = nlmsg_data(nlh);
300 	int err;
301 
302 	if (!netlink_capable(skb, CAP_NET_ADMIN))
303 		return -EPERM;
304 
305 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
306 		return -EINVAL;
307 
308 	alg = crypto_alg_match(p, 1);
309 	if (!alg)
310 		return -ENOENT;
311 
312 	/* We can not unregister core algorithms such as aes-generic.
313 	 * We would loose the reference in the crypto_alg_list to this algorithm
314 	 * if we try to unregister. Unregistering such an algorithm without
315 	 * removing the module is not possible, so we restrict to crypto
316 	 * instances that are build from templates. */
317 	err = -EINVAL;
318 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
319 		goto drop_alg;
320 
321 	err = -EBUSY;
322 	if (refcount_read(&alg->cra_refcnt) > 2)
323 		goto drop_alg;
324 
325 	err = crypto_unregister_instance((struct crypto_instance *)alg);
326 
327 drop_alg:
328 	crypto_mod_put(alg);
329 	return err;
330 }
331 
332 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
333 			  struct nlattr **attrs)
334 {
335 	int exact = 0;
336 	const char *name;
337 	struct crypto_alg *alg;
338 	struct crypto_user_alg *p = nlmsg_data(nlh);
339 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
340 
341 	if (!netlink_capable(skb, CAP_NET_ADMIN))
342 		return -EPERM;
343 
344 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
345 		return -EINVAL;
346 
347 	if (strlen(p->cru_driver_name))
348 		exact = 1;
349 
350 	if (priority && !exact)
351 		return -EINVAL;
352 
353 	alg = crypto_alg_match(p, exact);
354 	if (alg) {
355 		crypto_mod_put(alg);
356 		return -EEXIST;
357 	}
358 
359 	if (strlen(p->cru_driver_name))
360 		name = p->cru_driver_name;
361 	else
362 		name = p->cru_name;
363 
364 	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
365 	if (IS_ERR(alg))
366 		return PTR_ERR(alg);
367 
368 	down_write(&crypto_alg_sem);
369 
370 	if (priority)
371 		alg->cra_priority = nla_get_u32(priority);
372 
373 	up_write(&crypto_alg_sem);
374 
375 	crypto_mod_put(alg);
376 
377 	return 0;
378 }
379 
380 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
381 			  struct nlattr **attrs)
382 {
383 	if (!netlink_capable(skb, CAP_NET_ADMIN))
384 		return -EPERM;
385 	return crypto_del_default_rng();
386 }
387 
388 #define MSGSIZE(type) sizeof(struct type)
389 
390 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
391 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
392 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
393 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
394 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
395 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
396 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
397 };
398 
399 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
400 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
401 };
402 
403 #undef MSGSIZE
404 
405 static const struct crypto_link {
406 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
407 	int (*dump)(struct sk_buff *, struct netlink_callback *);
408 	int (*done)(struct netlink_callback *);
409 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
410 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
411 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
412 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
413 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
414 						       .dump = crypto_dump_report,
415 						       .done = crypto_dump_report_done},
416 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
417 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
418 };
419 
420 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
421 			       struct netlink_ext_ack *extack)
422 {
423 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
424 	const struct crypto_link *link;
425 	int type, err;
426 
427 	type = nlh->nlmsg_type;
428 	if (type > CRYPTO_MSG_MAX)
429 		return -EINVAL;
430 
431 	type -= CRYPTO_MSG_BASE;
432 	link = &crypto_dispatch[type];
433 
434 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
435 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
436 		struct crypto_alg *alg;
437 		unsigned long dump_alloc = 0;
438 
439 		if (link->dump == NULL)
440 			return -EINVAL;
441 
442 		down_read(&crypto_alg_sem);
443 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
444 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
445 		up_read(&crypto_alg_sem);
446 
447 		{
448 			struct netlink_dump_control c = {
449 				.dump = link->dump,
450 				.done = link->done,
451 				.min_dump_alloc = min(dump_alloc, 65535UL),
452 			};
453 			err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
454 		}
455 
456 		return err;
457 	}
458 
459 	err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
460 				     CRYPTOCFGA_MAX, crypto_policy, extack);
461 	if (err < 0)
462 		return err;
463 
464 	if (link->doit == NULL)
465 		return -EINVAL;
466 
467 	return link->doit(skb, nlh, attrs);
468 }
469 
470 static void crypto_netlink_rcv(struct sk_buff *skb)
471 {
472 	mutex_lock(&crypto_cfg_mutex);
473 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
474 	mutex_unlock(&crypto_cfg_mutex);
475 }
476 
477 static int __init crypto_user_init(void)
478 {
479 	struct netlink_kernel_cfg cfg = {
480 		.input	= crypto_netlink_rcv,
481 	};
482 
483 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
484 	if (!crypto_nlsk)
485 		return -ENOMEM;
486 
487 	return 0;
488 }
489 
490 static void __exit crypto_user_exit(void)
491 {
492 	netlink_kernel_release(crypto_nlsk);
493 }
494 
495 module_init(crypto_user_init);
496 module_exit(crypto_user_exit);
497 MODULE_LICENSE("GPL");
498 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
499 MODULE_DESCRIPTION("Crypto userspace configuration API");
500 MODULE_ALIAS("net-pf-16-proto-21");
501