summaryrefslogtreecommitdiff
path: root/crypto/authencesn.c
blob: c30393e2ad225062a936df3545cf5effe41b8413 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
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
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
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
268
269
270
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
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
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
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
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
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
/*
 * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
 *                 derived from authenc.c
 *
 * Copyright (C) 2010 secunet Security Networks AG
 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <crypto/internal/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/authenc.h>
#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

struct authenc_esn_instance_ctx {
	struct crypto_ahash_spawn auth;
	struct crypto_skcipher_spawn enc;
};

struct crypto_authenc_esn_ctx {
	unsigned int reqoff;
	struct crypto_ahash *auth;
	struct crypto_ablkcipher *enc;
	struct crypto_blkcipher *null;
};

struct authenc_esn_request_ctx {
	struct scatterlist src[2];
	struct scatterlist dst[2];
	char tail[];
};

static void authenc_esn_request_complete(struct aead_request *req, int err)
{
	if (err != -EINPROGRESS)
		aead_request_complete(req, err);
}

static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
					  unsigned int authsize)
{
	if (authsize > 0 && authsize < 4)
		return -EINVAL;

	return 0;
}

static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
				     unsigned int keylen)
{
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct crypto_ahash *auth = ctx->auth;
	struct crypto_ablkcipher *enc = ctx->enc;
	struct crypto_authenc_keys keys;
	int err = -EINVAL;

	if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
		goto badkey;

	crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
	crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
				     CRYPTO_TFM_REQ_MASK);
	err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
	crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) &
					   CRYPTO_TFM_RES_MASK);

	if (err)
		goto out;

	crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
	crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
					 CRYPTO_TFM_REQ_MASK);
	err = crypto_ablkcipher_setkey(enc, keys.enckey, keys.enckeylen);
	crypto_aead_set_flags(authenc_esn, crypto_ablkcipher_get_flags(enc) &
					   CRYPTO_TFM_RES_MASK);

out:
	return err;

badkey:
	crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN);
	goto out;
}

static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
					  unsigned int flags)
{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_ahash *auth = ctx->auth;
	u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
			     crypto_ahash_alignmask(auth) + 1);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	struct scatterlist *dst = req->dst;
	u32 tmp[2];

	/* Move high-order bits of sequence number back. */
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);

	scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
	return 0;
}

static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
					 int err)
{
	struct aead_request *req = areq->data;

	err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
	aead_request_complete(req, err);
}

static int crypto_authenc_esn_genicv(struct aead_request *req,
				     unsigned int flags)
{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct crypto_ahash *auth = ctx->auth;
	u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
			     crypto_ahash_alignmask(auth) + 1);
	struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	struct scatterlist *dst = req->dst;
	u32 tmp[2];

	if (!authsize)
		return 0;

	/* Move high-order bits of sequence number to the end. */
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);

	ahash_request_set_tfm(ahreq, auth);
	ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
	ahash_request_set_callback(ahreq, flags,
				   authenc_esn_geniv_ahash_done, req);

	return crypto_ahash_digest(ahreq) ?:
	       crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
}


static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
					    int err)
{
	struct aead_request *areq = req->data;

	if (!err)
		err = crypto_authenc_esn_genicv(areq, 0);

	authenc_esn_request_complete(areq, err);
}

static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct blkcipher_desc desc = {
		.tfm = ctx->null,
	};

	return crypto_blkcipher_encrypt(&desc, req->dst, req->src, len);
}

static int crypto_authenc_esn_encrypt(struct aead_request *req)
{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct ablkcipher_request *abreq = (void *)(areq_ctx->tail
						    + ctx->reqoff);
	struct crypto_ablkcipher *enc = ctx->enc;
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	struct scatterlist *src, *dst;
	int err;

	sg_init_table(areq_ctx->src, 2);
	src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
	dst = src;

	if (req->src != req->dst) {
		err = crypto_authenc_esn_copy(req, assoclen);
		if (err)
			return err;

		sg_init_table(areq_ctx->dst, 2);
		dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
	}

	ablkcipher_request_set_tfm(abreq, enc);
	ablkcipher_request_set_callback(abreq, aead_request_flags(req),
					crypto_authenc_esn_encrypt_done, req);
	ablkcipher_request_set_crypt(abreq, src, dst, cryptlen, req->iv);

	err = crypto_ablkcipher_encrypt(abreq);
	if (err)
		return err;

	return crypto_authenc_esn_genicv(req, aead_request_flags(req));
}

static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
					   unsigned int flags)
{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct ablkcipher_request *abreq = (void *)(areq_ctx->tail
						    + ctx->reqoff);
	struct crypto_ahash *auth = ctx->auth;
	u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
			      crypto_ahash_alignmask(auth) + 1);
	unsigned int cryptlen = req->cryptlen - authsize;
	unsigned int assoclen = req->assoclen;
	struct scatterlist *dst = req->dst;
	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
	u32 tmp[2];

	/* Move high-order bits of sequence number back. */
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);

	if (crypto_memneq(ihash, ohash, authsize))
		return -EBADMSG;

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);

	ablkcipher_request_set_tfm(abreq, ctx->enc);
	ablkcipher_request_set_callback(abreq, flags,
					req->base.complete, req->base.data);
	ablkcipher_request_set_crypt(abreq, dst, dst, cryptlen, req->iv);

	return crypto_ablkcipher_decrypt(abreq);
}

static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
					  int err)
{
	struct aead_request *req = areq->data;

	err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
	aead_request_complete(req, err);
}

static int crypto_authenc_esn_decrypt(struct aead_request *req)
{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	struct crypto_ahash *auth = ctx->auth;
	u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
			      crypto_ahash_alignmask(auth) + 1);
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
	struct scatterlist *dst = req->dst;
	u32 tmp[2];
	int err;

	cryptlen -= authsize;

	if (req->src != dst) {
		err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
		if (err)
			return err;
	}

	scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
				 authsize, 0);

	if (!authsize)
		goto tail;

	/* Move high-order bits of sequence number to the end. */
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);

	ahash_request_set_tfm(ahreq, auth);
	ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
	ahash_request_set_callback(ahreq, aead_request_flags(req),
				   authenc_esn_verify_ahash_done, req);

	err = crypto_ahash_digest(ahreq);
	if (err)
		return err;

tail:
	return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
}

static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
	struct crypto_ahash *auth;
	struct crypto_ablkcipher *enc;
	struct crypto_blkcipher *null;
	int err;

	auth = crypto_spawn_ahash(&ictx->auth);
	if (IS_ERR(auth))
		return PTR_ERR(auth);

	enc = crypto_spawn_skcipher(&ictx->enc);
	err = PTR_ERR(enc);
	if (IS_ERR(enc))
		goto err_free_ahash;

	null = crypto_get_default_null_skcipher();
	err = PTR_ERR(null);
	if (IS_ERR(null))
		goto err_free_skcipher;

	ctx->auth = auth;
	ctx->enc = enc;
	ctx->null = null;

	ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
			    crypto_ahash_alignmask(auth) + 1);

	crypto_aead_set_reqsize(
		tfm,
		sizeof(struct authenc_esn_request_ctx) +
		ctx->reqoff +
		max_t(unsigned int,
			crypto_ahash_reqsize(auth) +
			sizeof(struct ahash_request),
			sizeof(struct skcipher_givcrypt_request) +
			crypto_ablkcipher_reqsize(enc)));

	return 0;

err_free_skcipher:
	crypto_free_ablkcipher(enc);
err_free_ahash:
	crypto_free_ahash(auth);
	return err;
}

static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
{
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);

	crypto_free_ahash(ctx->auth);
	crypto_free_ablkcipher(ctx->enc);
	crypto_put_default_null_skcipher();
}

static void crypto_authenc_esn_free(struct aead_instance *inst)
{
	struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);

	crypto_drop_skcipher(&ctx->enc);
	crypto_drop_ahash(&ctx->auth);
	kfree(inst);
}

static int crypto_authenc_esn_create(struct crypto_template *tmpl,
				     struct rtattr **tb)
{
	struct crypto_attr_type *algt;
	struct aead_instance *inst;
	struct hash_alg_common *auth;
	struct crypto_alg *auth_base;
	struct crypto_alg *enc;
	struct authenc_esn_instance_ctx *ctx;
	const char *enc_name;
	int err;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_AEAD_NEW)) &
	    algt->mask)
		return -EINVAL;

	auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
			       CRYPTO_ALG_TYPE_AHASH_MASK);
	if (IS_ERR(auth))
		return PTR_ERR(auth);

	auth_base = &auth->base;

	enc_name = crypto_attr_alg_name(tb[2]);
	err = PTR_ERR(enc_name);
	if (IS_ERR(enc_name))
		goto out_put_auth;

	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
	err = -ENOMEM;
	if (!inst)
		goto out_put_auth;

	ctx = aead_instance_ctx(inst);

	err = crypto_init_ahash_spawn(&ctx->auth, auth,
				      aead_crypto_instance(inst));
	if (err)
		goto err_free_inst;

	crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst));
	err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
				   crypto_requires_sync(algt->type,
							algt->mask));
	if (err)
		goto err_drop_auth;

	enc = crypto_skcipher_spawn_alg(&ctx->enc);

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
		     "authencesn(%s,%s)", auth_base->cra_name,
		     enc->cra_name) >= CRYPTO_MAX_ALG_NAME)
		goto err_drop_enc;

	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "authencesn(%s,%s)", auth_base->cra_driver_name,
		     enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
		goto err_drop_enc;

	inst->alg.base.cra_flags = enc->cra_flags & CRYPTO_ALG_ASYNC;
	inst->alg.base.cra_flags |= CRYPTO_ALG_AEAD_NEW;
	inst->alg.base.cra_priority = enc->cra_priority * 10 +
				      auth_base->cra_priority;
	inst->alg.base.cra_blocksize = enc->cra_blocksize;
	inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
				       enc->cra_alignmask;
	inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);

	inst->alg.ivsize = enc->cra_ablkcipher.ivsize;
	inst->alg.maxauthsize = auth->digestsize;

	inst->alg.init = crypto_authenc_esn_init_tfm;
	inst->alg.exit = crypto_authenc_esn_exit_tfm;

	inst->alg.setkey = crypto_authenc_esn_setkey;
	inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
	inst->alg.encrypt = crypto_authenc_esn_encrypt;
	inst->alg.decrypt = crypto_authenc_esn_decrypt;

	inst->free = crypto_authenc_esn_free,

	err = aead_register_instance(tmpl, inst);
	if (err)
		goto err_drop_enc;

out:
	crypto_mod_put(auth_base);
	return err;

err_drop_enc:
	crypto_drop_skcipher(&ctx->enc);
err_drop_auth:
	crypto_drop_ahash(&ctx->auth);
err_free_inst:
	kfree(inst);
out_put_auth:
	goto out;
}

static struct crypto_template crypto_authenc_esn_tmpl = {
	.name = "authencesn",
	.create = crypto_authenc_esn_create,
	.module = THIS_MODULE,
};

static int __init crypto_authenc_esn_module_init(void)
{
	return crypto_register_template(&crypto_authenc_esn_tmpl);
}

static void __exit crypto_authenc_esn_module_exit(void)
{
	crypto_unregister_template(&crypto_authenc_esn_tmpl);
}

module_init(crypto_authenc_esn_module_init);
module_exit(crypto_authenc_esn_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
MODULE_ALIAS_CRYPTO("authencesn");