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/aead.h>
29#include <crypto/internal/skcipher.h>
30
31#include "internal.h"
32
33#define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))
34
35static DEFINE_MUTEX(crypto_cfg_mutex);
36
37/* The crypto netlink socket */
38static struct sock *crypto_nlsk;
39
40struct crypto_dump_info {
41	struct sk_buff *in_skb;
42	struct sk_buff *out_skb;
43	u32 nlmsg_seq;
44	u16 nlmsg_flags;
45};
46
47static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
48{
49	struct crypto_alg *q, *alg = NULL;
50
51	down_read(&crypto_alg_sem);
52
53	list_for_each_entry(q, &crypto_alg_list, cra_list) {
54		int match = 0;
55
56		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
57			continue;
58
59		if (strlen(p->cru_driver_name))
60			match = !strcmp(q->cra_driver_name,
61					p->cru_driver_name);
62		else if (!exact)
63			match = !strcmp(q->cra_name, p->cru_name);
64
65		if (!match)
66			continue;
67
68		if (unlikely(!crypto_mod_get(q)))
69			continue;
70
71		alg = q;
72		break;
73	}
74
75	up_read(&crypto_alg_sem);
76
77	return alg;
78}
79
80static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
81{
82	struct crypto_report_cipher rcipher;
83
84	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
85
86	rcipher.blocksize = alg->cra_blocksize;
87	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
88	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
89
90	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
91		    sizeof(struct crypto_report_cipher), &rcipher))
92		goto nla_put_failure;
93	return 0;
94
95nla_put_failure:
96	return -EMSGSIZE;
97}
98
99static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
100{
101	struct crypto_report_comp rcomp;
102
103	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
104	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
105		    sizeof(struct crypto_report_comp), &rcomp))
106		goto nla_put_failure;
107	return 0;
108
109nla_put_failure:
110	return -EMSGSIZE;
111}
112
113static int crypto_report_one(struct crypto_alg *alg,
114			     struct crypto_user_alg *ualg, struct sk_buff *skb)
115{
116	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
117	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
118		sizeof(ualg->cru_driver_name));
119	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
120		sizeof(ualg->cru_module_name));
121
122	ualg->cru_type = 0;
123	ualg->cru_mask = 0;
124	ualg->cru_flags = alg->cra_flags;
125	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
126
127	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
128		goto nla_put_failure;
129	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
130		struct crypto_report_larval rl;
131
132		strncpy(rl.type, "larval", sizeof(rl.type));
133		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
134			    sizeof(struct crypto_report_larval), &rl))
135			goto nla_put_failure;
136		goto out;
137	}
138
139	if (alg->cra_type && alg->cra_type->report) {
140		if (alg->cra_type->report(skb, alg))
141			goto nla_put_failure;
142
143		goto out;
144	}
145
146	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
147	case CRYPTO_ALG_TYPE_CIPHER:
148		if (crypto_report_cipher(skb, alg))
149			goto nla_put_failure;
150
151		break;
152	case CRYPTO_ALG_TYPE_COMPRESS:
153		if (crypto_report_comp(skb, alg))
154			goto nla_put_failure;
155
156		break;
157	}
158
159out:
160	return 0;
161
162nla_put_failure:
163	return -EMSGSIZE;
164}
165
166static int crypto_report_alg(struct crypto_alg *alg,
167			     struct crypto_dump_info *info)
168{
169	struct sk_buff *in_skb = info->in_skb;
170	struct sk_buff *skb = info->out_skb;
171	struct nlmsghdr *nlh;
172	struct crypto_user_alg *ualg;
173	int err = 0;
174
175	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
176			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
177	if (!nlh) {
178		err = -EMSGSIZE;
179		goto out;
180	}
181
182	ualg = nlmsg_data(nlh);
183
184	err = crypto_report_one(alg, ualg, skb);
185	if (err) {
186		nlmsg_cancel(skb, nlh);
187		goto out;
188	}
189
190	nlmsg_end(skb, nlh);
191
192out:
193	return err;
194}
195
196static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
197			 struct nlattr **attrs)
198{
199	struct crypto_user_alg *p = nlmsg_data(in_nlh);
200	struct crypto_alg *alg;
201	struct sk_buff *skb;
202	struct crypto_dump_info info;
203	int err;
204
205	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
206		return -EINVAL;
207
208	alg = crypto_alg_match(p, 0);
209	if (!alg)
210		return -ENOENT;
211
212	err = -ENOMEM;
213	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
214	if (!skb)
215		goto drop_alg;
216
217	info.in_skb = in_skb;
218	info.out_skb = skb;
219	info.nlmsg_seq = in_nlh->nlmsg_seq;
220	info.nlmsg_flags = 0;
221
222	err = crypto_report_alg(alg, &info);
223
224drop_alg:
225	crypto_mod_put(alg);
226
227	if (err)
228		return err;
229
230	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
231}
232
233static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
234{
235	struct crypto_alg *alg;
236	struct crypto_dump_info info;
237	int err;
238
239	if (cb->args[0])
240		goto out;
241
242	cb->args[0] = 1;
243
244	info.in_skb = cb->skb;
245	info.out_skb = skb;
246	info.nlmsg_seq = cb->nlh->nlmsg_seq;
247	info.nlmsg_flags = NLM_F_MULTI;
248
249	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
250		err = crypto_report_alg(alg, &info);
251		if (err)
252			goto out_err;
253	}
254
255out:
256	return skb->len;
257out_err:
258	return err;
259}
260
261static int crypto_dump_report_done(struct netlink_callback *cb)
262{
263	return 0;
264}
265
266static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
267			     struct nlattr **attrs)
268{
269	struct crypto_alg *alg;
270	struct crypto_user_alg *p = nlmsg_data(nlh);
271	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
272	LIST_HEAD(list);
273
274	if (!netlink_capable(skb, CAP_NET_ADMIN))
275		return -EPERM;
276
277	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
278		return -EINVAL;
279
280	if (priority && !strlen(p->cru_driver_name))
281		return -EINVAL;
282
283	alg = crypto_alg_match(p, 1);
284	if (!alg)
285		return -ENOENT;
286
287	down_write(&crypto_alg_sem);
288
289	crypto_remove_spawns(alg, &list, NULL);
290
291	if (priority)
292		alg->cra_priority = nla_get_u32(priority);
293
294	up_write(&crypto_alg_sem);
295
296	crypto_mod_put(alg);
297	crypto_remove_final(&list);
298
299	return 0;
300}
301
302static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
303			  struct nlattr **attrs)
304{
305	struct crypto_alg *alg;
306	struct crypto_user_alg *p = nlmsg_data(nlh);
307	int err;
308
309	if (!netlink_capable(skb, CAP_NET_ADMIN))
310		return -EPERM;
311
312	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
313		return -EINVAL;
314
315	alg = crypto_alg_match(p, 1);
316	if (!alg)
317		return -ENOENT;
318
319	/* We can not unregister core algorithms such as aes-generic.
320	 * We would loose the reference in the crypto_alg_list to this algorithm
321	 * if we try to unregister. Unregistering such an algorithm without
322	 * removing the module is not possible, so we restrict to crypto
323	 * instances that are build from templates. */
324	err = -EINVAL;
325	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
326		goto drop_alg;
327
328	err = -EBUSY;
329	if (atomic_read(&alg->cra_refcnt) > 2)
330		goto drop_alg;
331
332	err = crypto_unregister_instance((struct crypto_instance *)alg);
333
334drop_alg:
335	crypto_mod_put(alg);
336	return err;
337}
338
339static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
340						   u32 mask)
341{
342	int err;
343	struct crypto_alg *alg;
344
345	type = crypto_skcipher_type(type);
346	mask = crypto_skcipher_mask(mask);
347
348	for (;;) {
349		alg = crypto_lookup_skcipher(name,  type, mask);
350		if (!IS_ERR(alg))
351			return alg;
352
353		err = PTR_ERR(alg);
354		if (err != -EAGAIN)
355			break;
356		if (signal_pending(current)) {
357			err = -EINTR;
358			break;
359		}
360	}
361
362	return ERR_PTR(err);
363}
364
365static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
366					       u32 mask)
367{
368	int err;
369	struct crypto_alg *alg;
370
371	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
372	type |= CRYPTO_ALG_TYPE_AEAD;
373	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
374	mask |= CRYPTO_ALG_TYPE_MASK;
375
376	for (;;) {
377		alg = crypto_lookup_aead(name,  type, mask);
378		if (!IS_ERR(alg))
379			return alg;
380
381		err = PTR_ERR(alg);
382		if (err != -EAGAIN)
383			break;
384		if (fatal_signal_pending(current)) {
385			err = -EINTR;
386			break;
387		}
388	}
389
390	return ERR_PTR(err);
391}
392
393static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
394			  struct nlattr **attrs)
395{
396	int exact = 0;
397	const char *name;
398	struct crypto_alg *alg;
399	struct crypto_user_alg *p = nlmsg_data(nlh);
400	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
401
402	if (!netlink_capable(skb, CAP_NET_ADMIN))
403		return -EPERM;
404
405	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
406		return -EINVAL;
407
408	if (strlen(p->cru_driver_name))
409		exact = 1;
410
411	if (priority && !exact)
412		return -EINVAL;
413
414	alg = crypto_alg_match(p, exact);
415	if (alg) {
416		crypto_mod_put(alg);
417		return -EEXIST;
418	}
419
420	if (strlen(p->cru_driver_name))
421		name = p->cru_driver_name;
422	else
423		name = p->cru_name;
424
425	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
426	case CRYPTO_ALG_TYPE_AEAD:
427		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
428		break;
429	case CRYPTO_ALG_TYPE_GIVCIPHER:
430	case CRYPTO_ALG_TYPE_BLKCIPHER:
431	case CRYPTO_ALG_TYPE_ABLKCIPHER:
432		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
433		break;
434	default:
435		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
436	}
437
438	if (IS_ERR(alg))
439		return PTR_ERR(alg);
440
441	down_write(&crypto_alg_sem);
442
443	if (priority)
444		alg->cra_priority = nla_get_u32(priority);
445
446	up_write(&crypto_alg_sem);
447
448	crypto_mod_put(alg);
449
450	return 0;
451}
452
453#define MSGSIZE(type) sizeof(struct type)
454
455static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
456	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
457	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
458	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
459	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
460};
461
462static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
463	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
464};
465
466#undef MSGSIZE
467
468static const struct crypto_link {
469	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
470	int (*dump)(struct sk_buff *, struct netlink_callback *);
471	int (*done)(struct netlink_callback *);
472} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
473	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
474	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
475	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
476	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
477						       .dump = crypto_dump_report,
478						       .done = crypto_dump_report_done},
479};
480
481static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
482{
483	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
484	const struct crypto_link *link;
485	int type, err;
486
487	type = nlh->nlmsg_type;
488	if (type > CRYPTO_MSG_MAX)
489		return -EINVAL;
490
491	type -= CRYPTO_MSG_BASE;
492	link = &crypto_dispatch[type];
493
494	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
495	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
496		struct crypto_alg *alg;
497		u16 dump_alloc = 0;
498
499		if (link->dump == NULL)
500			return -EINVAL;
501
502		down_read(&crypto_alg_sem);
503		list_for_each_entry(alg, &crypto_alg_list, cra_list)
504			dump_alloc += CRYPTO_REPORT_MAXSIZE;
505
506		{
507			struct netlink_dump_control c = {
508				.dump = link->dump,
509				.done = link->done,
510				.min_dump_alloc = dump_alloc,
511			};
512			err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
513		}
514		up_read(&crypto_alg_sem);
515
516		return err;
517	}
518
519	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
520			  crypto_policy);
521	if (err < 0)
522		return err;
523
524	if (link->doit == NULL)
525		return -EINVAL;
526
527	return link->doit(skb, nlh, attrs);
528}
529
530static void crypto_netlink_rcv(struct sk_buff *skb)
531{
532	mutex_lock(&crypto_cfg_mutex);
533	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
534	mutex_unlock(&crypto_cfg_mutex);
535}
536
537static int __init crypto_user_init(void)
538{
539	struct netlink_kernel_cfg cfg = {
540		.input	= crypto_netlink_rcv,
541	};
542
543	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
544	if (!crypto_nlsk)
545		return -ENOMEM;
546
547	return 0;
548}
549
550static void __exit crypto_user_exit(void)
551{
552	netlink_kernel_release(crypto_nlsk);
553}
554
555module_init(crypto_user_init);
556module_exit(crypto_user_exit);
557MODULE_LICENSE("GPL");
558MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
559MODULE_DESCRIPTION("Crypto userspace configuration API");
560MODULE_ALIAS("net-pf-16-proto-21");
561