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
27static DEFINE_MUTEX(crypto_cfg_mutex);
28
29struct 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
36struct 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
72static 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
88static 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
99static 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
147out:
148	return 0;
149
150nla_put_failure:
151	return -EMSGSIZE;
152}
153
154static 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
180out:
181	return err;
182}
183
184static 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
213drop_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
224static 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;
250out:
251	up_read(&crypto_alg_sem);
252	return res;
253}
254
255static int crypto_dump_report_done(struct netlink_callback *cb)
256{
257	return 0;
258}
259
260static 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
296static 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	crypto_unregister_instance((struct crypto_instance *)alg);
327	err = 0;
328
329drop_alg:
330	crypto_mod_put(alg);
331	return err;
332}
333
334static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
335			  struct nlattr **attrs)
336{
337	int exact = 0;
338	const char *name;
339	struct crypto_alg *alg;
340	struct crypto_user_alg *p = nlmsg_data(nlh);
341	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
342
343	if (!netlink_capable(skb, CAP_NET_ADMIN))
344		return -EPERM;
345
346	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
347		return -EINVAL;
348
349	if (strlen(p->cru_driver_name))
350		exact = 1;
351
352	if (priority && !exact)
353		return -EINVAL;
354
355	alg = crypto_alg_match(p, exact);
356	if (alg) {
357		crypto_mod_put(alg);
358		return -EEXIST;
359	}
360
361	if (strlen(p->cru_driver_name))
362		name = p->cru_driver_name;
363	else
364		name = p->cru_name;
365
366	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
367	if (IS_ERR(alg))
368		return PTR_ERR(alg);
369
370	down_write(&crypto_alg_sem);
371
372	if (priority)
373		alg->cra_priority = nla_get_u32(priority);
374
375	up_write(&crypto_alg_sem);
376
377	crypto_mod_put(alg);
378
379	return 0;
380}
381
382static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
383			  struct nlattr **attrs)
384{
385	if (!netlink_capable(skb, CAP_NET_ADMIN))
386		return -EPERM;
387	return crypto_del_default_rng();
388}
389
390#define MSGSIZE(type) sizeof(struct type)
391
392static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
393	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
394	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
395	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
396	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
397	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
398	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
399};
400
401static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
402	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
403};
404
405#undef MSGSIZE
406
407static const struct crypto_link {
408	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
409	int (*dump)(struct sk_buff *, struct netlink_callback *);
410	int (*done)(struct netlink_callback *);
411} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
412	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
413	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
414	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
415	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
416						       .dump = crypto_dump_report,
417						       .done = crypto_dump_report_done},
418	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
419	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
420};
421
422static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
423			       struct netlink_ext_ack *extack)
424{
425	struct net *net = sock_net(skb->sk);
426	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
427	const struct crypto_link *link;
428	int type, err;
429
430	type = nlh->nlmsg_type;
431	if (type > CRYPTO_MSG_MAX)
432		return -EINVAL;
433
434	type -= CRYPTO_MSG_BASE;
435	link = &crypto_dispatch[type];
436
437	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
438	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
439		struct crypto_alg *alg;
440		unsigned long dump_alloc = 0;
441
442		if (link->dump == NULL)
443			return -EINVAL;
444
445		down_read(&crypto_alg_sem);
446		list_for_each_entry(alg, &crypto_alg_list, cra_list)
447			dump_alloc += CRYPTO_REPORT_MAXSIZE;
448		up_read(&crypto_alg_sem);
449
450		{
451			struct netlink_dump_control c = {
452				.dump = link->dump,
453				.done = link->done,
454				.min_dump_alloc = min(dump_alloc, 65535UL),
455			};
456			err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
457		}
458
459		return err;
460	}
461
462	err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
463				     CRYPTOCFGA_MAX, crypto_policy, extack);
464	if (err < 0)
465		return err;
466
467	if (link->doit == NULL)
468		return -EINVAL;
469
470	return link->doit(skb, nlh, attrs);
471}
472
473static void crypto_netlink_rcv(struct sk_buff *skb)
474{
475	mutex_lock(&crypto_cfg_mutex);
476	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
477	mutex_unlock(&crypto_cfg_mutex);
478}
479
480static int __net_init crypto_netlink_init(struct net *net)
481{
482	struct netlink_kernel_cfg cfg = {
483		.input	= crypto_netlink_rcv,
484	};
485
486	net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
487	return net->crypto_nlsk == NULL ? -ENOMEM : 0;
488}
489
490static void __net_exit crypto_netlink_exit(struct net *net)
491{
492	netlink_kernel_release(net->crypto_nlsk);
493	net->crypto_nlsk = NULL;
494}
495
496static struct pernet_operations crypto_netlink_net_ops = {
497	.init = crypto_netlink_init,
498	.exit = crypto_netlink_exit,
499};
500
501static int __init crypto_user_init(void)
502{
503	return register_pernet_subsys(&crypto_netlink_net_ops);
504}
505
506static void __exit crypto_user_exit(void)
507{
508	unregister_pernet_subsys(&crypto_netlink_net_ops);
509}
510
511module_init(crypto_user_init);
512module_exit(crypto_user_exit);
513MODULE_LICENSE("GPL");
514MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
515MODULE_DESCRIPTION("Crypto userspace configuration API");
516MODULE_ALIAS("net-pf-16-proto-21");
517