crypto_user.c 12.3 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
/*
 * Crypto user configuration API.
 *
 * Copyright (C) 2011 secunet Security Networks AG
 * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/cryptouser.h>
24
#include <linux/sched.h>
25 26 27
#include <net/netlink.h>
#include <linux/security.h>
#include <net/net_namespace.h>
28 29 30
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>

31 32
#include "internal.h"

33 34
#define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))

35
static DEFINE_MUTEX(crypto_cfg_mutex);
36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

/* The crypto netlink socket */
static struct sock *crypto_nlsk;

struct crypto_dump_info {
	struct sk_buff *in_skb;
	struct sk_buff *out_skb;
	u32 nlmsg_seq;
	u16 nlmsg_flags;
};

static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
{
	struct crypto_alg *q, *alg = NULL;

	down_read(&crypto_alg_sem);

	list_for_each_entry(q, &crypto_alg_list, cra_list) {
54
		int match = 0;
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
			continue;

		if (strlen(p->cru_driver_name))
			match = !strcmp(q->cra_driver_name,
					p->cru_driver_name);
		else if (!exact)
			match = !strcmp(q->cra_name, p->cru_name);

		if (match) {
			alg = q;
			break;
		}
	}

	up_read(&crypto_alg_sem);

	return alg;
}

76 77 78 79
static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
{
	struct crypto_report_cipher rcipher;

80
	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
81 82 83 84 85

	rcipher.blocksize = alg->cra_blocksize;
	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

86 87 88
	if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
		    sizeof(struct crypto_report_cipher), &rcipher))
		goto nla_put_failure;
89 90 91 92 93 94
	return 0;

nla_put_failure:
	return -EMSGSIZE;
}

95 96 97 98
static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
{
	struct crypto_report_comp rcomp;

99
	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
100 101 102
	if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
		    sizeof(struct crypto_report_comp), &rcomp))
		goto nla_put_failure;
103 104 105 106 107 108
	return 0;

nla_put_failure:
	return -EMSGSIZE;
}

109 110 111
static int crypto_report_one(struct crypto_alg *alg,
			     struct crypto_user_alg *ualg, struct sk_buff *skb)
{
112 113 114 115 116 117 118 119
	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
		sizeof(ualg->cru_driver_name));
	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
		sizeof(ualg->cru_module_name));

	ualg->cru_type = 0;
	ualg->cru_mask = 0;
120 121 122
	ualg->cru_flags = alg->cra_flags;
	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);

123 124
	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
		goto nla_put_failure;
125 126 127
	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
		struct crypto_report_larval rl;

128
		strncpy(rl.type, "larval", sizeof(rl.type));
129 130 131
		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
			    sizeof(struct crypto_report_larval), &rl))
			goto nla_put_failure;
132 133 134
		goto out;
	}

135 136 137
	if (alg->cra_type && alg->cra_type->report) {
		if (alg->cra_type->report(skb, alg))
			goto nla_put_failure;
138 139 140 141 142 143 144 145 146

		goto out;
	}

	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		if (crypto_report_cipher(skb, alg))
			goto nla_put_failure;

147 148 149 150 151
		break;
	case CRYPTO_ALG_TYPE_COMPRESS:
		if (crypto_report_comp(skb, alg))
			goto nla_put_failure;

152
		break;
153 154
	}

155
out:
156 157 158 159 160 161 162 163 164 165 166 167 168 169 170
	return 0;

nla_put_failure:
	return -EMSGSIZE;
}

static int crypto_report_alg(struct crypto_alg *alg,
			     struct crypto_dump_info *info)
{
	struct sk_buff *in_skb = info->in_skb;
	struct sk_buff *skb = info->out_skb;
	struct nlmsghdr *nlh;
	struct crypto_user_alg *ualg;
	int err = 0;

171
	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200
			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
	if (!nlh) {
		err = -EMSGSIZE;
		goto out;
	}

	ualg = nlmsg_data(nlh);

	err = crypto_report_one(alg, ualg, skb);
	if (err) {
		nlmsg_cancel(skb, nlh);
		goto out;
	}

	nlmsg_end(skb, nlh);

out:
	return err;
}

static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
			 struct nlattr **attrs)
{
	struct crypto_user_alg *p = nlmsg_data(in_nlh);
	struct crypto_alg *alg;
	struct sk_buff *skb;
	struct crypto_dump_info info;
	int err;

201 202 203
	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
		return -EINVAL;

204
	if (!p->cru_driver_name[0])
205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223
		return -EINVAL;

	alg = crypto_alg_match(p, 1);
	if (!alg)
		return -ENOENT;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (!skb)
		return -ENOMEM;

	info.in_skb = in_skb;
	info.out_skb = skb;
	info.nlmsg_seq = in_nlh->nlmsg_seq;
	info.nlmsg_flags = 0;

	err = crypto_report_alg(alg, &info);
	if (err)
		return err;

224
	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
}

static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct crypto_alg *alg;
	struct crypto_dump_info info;
	int err;

	if (cb->args[0])
		goto out;

	cb->args[0] = 1;

	info.in_skb = cb->skb;
	info.out_skb = skb;
	info.nlmsg_seq = cb->nlh->nlmsg_seq;
	info.nlmsg_flags = NLM_F_MULTI;

	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
		err = crypto_report_alg(alg, &info);
		if (err)
			goto out_err;
	}

out:
	return skb->len;
out_err:
	return err;
}

static int crypto_dump_report_done(struct netlink_callback *cb)
{
	return 0;
}

static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
			     struct nlattr **attrs)
{
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);
	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
	LIST_HEAD(list);

268 269 270
	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
		return -EINVAL;

271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297
	if (priority && !strlen(p->cru_driver_name))
		return -EINVAL;

	alg = crypto_alg_match(p, 1);
	if (!alg)
		return -ENOENT;

	down_write(&crypto_alg_sem);

	crypto_remove_spawns(alg, &list, NULL);

	if (priority)
		alg->cra_priority = nla_get_u32(priority);

	up_write(&crypto_alg_sem);

	crypto_remove_final(&list);

	return 0;
}

static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
			  struct nlattr **attrs)
{
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);

298 299 300
	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
		return -EINVAL;

301 302 303 304 305 306 307 308 309 310 311 312 313 314 315
	alg = crypto_alg_match(p, 1);
	if (!alg)
		return -ENOENT;

	/* We can not unregister core algorithms such as aes-generic.
	 * We would loose the reference in the crypto_alg_list to this algorithm
	 * if we try to unregister. Unregistering such an algorithm without
	 * removing the module is not possible, so we restrict to crypto
	 * instances that are build from templates. */
	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
		return -EINVAL;

	if (atomic_read(&alg->cra_refcnt) != 1)
		return -EBUSY;

316
	return crypto_unregister_instance(alg);
317 318
}

319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372
static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
						   u32 mask)
{
	int err;
	struct crypto_alg *alg;

	type = crypto_skcipher_type(type);
	mask = crypto_skcipher_mask(mask);

	for (;;) {
		alg = crypto_lookup_skcipher(name,  type, mask);
		if (!IS_ERR(alg))
			return alg;

		err = PTR_ERR(alg);
		if (err != -EAGAIN)
			break;
		if (signal_pending(current)) {
			err = -EINTR;
			break;
		}
	}

	return ERR_PTR(err);
}

static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
					       u32 mask)
{
	int err;
	struct crypto_alg *alg;

	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
	type |= CRYPTO_ALG_TYPE_AEAD;
	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
	mask |= CRYPTO_ALG_TYPE_MASK;

	for (;;) {
		alg = crypto_lookup_aead(name,  type, mask);
		if (!IS_ERR(alg))
			return alg;

		err = PTR_ERR(alg);
		if (err != -EAGAIN)
			break;
		if (signal_pending(current)) {
			err = -EINTR;
			break;
		}
	}

	return ERR_PTR(err);
}

373 374 375
static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
			  struct nlattr **attrs)
{
376
	int exact = 0;
377 378 379 380 381
	const char *name;
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);
	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];

382 383 384
	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
		return -EINVAL;

385 386 387 388 389 390 391 392 393 394 395 396 397 398 399
	if (strlen(p->cru_driver_name))
		exact = 1;

	if (priority && !exact)
		return -EINVAL;

	alg = crypto_alg_match(p, exact);
	if (alg)
		return -EEXIST;

	if (strlen(p->cru_driver_name))
		name = p->cru_driver_name;
	else
		name = p->cru_name;

400 401 402 403 404 405 406 407 408 409 410 411 412
	switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
	case CRYPTO_ALG_TYPE_AEAD:
		alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
		break;
	case CRYPTO_ALG_TYPE_GIVCIPHER:
	case CRYPTO_ALG_TYPE_BLKCIPHER:
	case CRYPTO_ALG_TYPE_ABLKCIPHER:
		alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
		break;
	default:
		alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
	}

413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442
	if (IS_ERR(alg))
		return PTR_ERR(alg);

	down_write(&crypto_alg_sem);

	if (priority)
		alg->cra_priority = nla_get_u32(priority);

	up_write(&crypto_alg_sem);

	crypto_mod_put(alg);

	return 0;
}

#define MSGSIZE(type) sizeof(struct type)

static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
};

static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
};

#undef MSGSIZE

443
static const struct crypto_link {
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458
	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
	int (*dump)(struct sk_buff *, struct netlink_callback *);
	int (*done)(struct netlink_callback *);
} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
						       .dump = crypto_dump_report,
						       .done = crypto_dump_report_done},
};

static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
459
	const struct crypto_link *link;
460 461 462 463 464 465 466 467 468
	int type, err;

	type = nlh->nlmsg_type;
	if (type > CRYPTO_MSG_MAX)
		return -EINVAL;

	type -= CRYPTO_MSG_BASE;
	link = &crypto_dispatch[type];

469
	if (!capable(CAP_NET_ADMIN))
470 471 472 473
		return -EPERM;

	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
474 475 476
		struct crypto_alg *alg;
		u16 dump_alloc = 0;

477 478
		if (link->dump == NULL)
			return -EINVAL;
479 480 481 482

		list_for_each_entry(alg, &crypto_alg_list, cra_list)
			dump_alloc += CRYPTO_REPORT_MAXSIZE;

483 484 485 486
		{
			struct netlink_dump_control c = {
				.dump = link->dump,
				.done = link->done,
487
				.min_dump_alloc = dump_alloc,
488 489 490
			};
			return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
		}
491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512
	}

	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
			  crypto_policy);
	if (err < 0)
		return err;

	if (link->doit == NULL)
		return -EINVAL;

	return link->doit(skb, nlh, attrs);
}

static void crypto_netlink_rcv(struct sk_buff *skb)
{
	mutex_lock(&crypto_cfg_mutex);
	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
	mutex_unlock(&crypto_cfg_mutex);
}

static int __init crypto_user_init(void)
{
513 514 515 516
	struct netlink_kernel_cfg cfg = {
		.input	= crypto_netlink_rcv,
	};

517
	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533
	if (!crypto_nlsk)
		return -ENOMEM;

	return 0;
}

static void __exit crypto_user_exit(void)
{
	netlink_kernel_release(crypto_nlsk);
}

module_init(crypto_user_init);
module_exit(crypto_user_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
MODULE_DESCRIPTION("Crypto userspace configuration API");