crypto_user.c

  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
 26static DEFINE_MUTEX(crypto_cfg_mutex);
 27
 28struct 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
 35static 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
 71static 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
 87static 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
130out:
131	return 0;
132
133nla_put_failure:
134	return -EMSGSIZE;
135}
136
137static 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
163out:
164	return err;
165}
166
167static 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
196drop_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
207static 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;
233out:
234	up_read(&crypto_alg_sem);
235	return res;
236}
237
238static int crypto_dump_report_done(struct netlink_callback *cb)
239{
240	return 0;
241}
242
243static 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
279static 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
312drop_alg:
313	crypto_mod_put(alg);
314	return err;
315}
316
317static 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
365static 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
373static 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
382static 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
391static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
392	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
393};
394
395#undef MSGSIZE
396
397static 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
412static 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
463static 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
470static 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
480static void __net_exit crypto_netlink_exit(struct net *net)
481{
482	netlink_kernel_release(net->crypto_nlsk);
483	net->crypto_nlsk = NULL;
484}
485
486static struct pernet_operations crypto_netlink_net_ops = {
487	.init = crypto_netlink_init,
488	.exit = crypto_netlink_exit,
489};
490
491static int __init crypto_user_init(void)
492{
493	return register_pernet_subsys(&crypto_netlink_net_ops);
494}
495
496static void __exit crypto_user_exit(void)
497{
498	unregister_pernet_subsys(&crypto_netlink_net_ops);
499}
500
501module_init(crypto_user_init);
502module_exit(crypto_user_exit);
503MODULE_LICENSE("GPL");
504MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
505MODULE_DESCRIPTION("Crypto userspace configuration API");
506MODULE_ALIAS("net-pf-16-proto-21");