aboutsummaryrefslogtreecommitdiff
path: root/crypto/aegis256.c
blob: 11f0f8ec9c7c27d77a8338a0451da8d387c15360 (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
/*
 * The AEGIS-256 Authenticated-Encryption Algorithm
 *
 * Copyright (c) 2017-2018 Ondrej Mosnacek <omosnacek@gmail.com>
 * Copyright (C) 2017-2018 Red Hat, Inc. All rights reserved.
 *
 * 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/algapi.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>

#include "aegis.h"

#define AEGIS256_NONCE_SIZE 32
#define AEGIS256_STATE_BLOCKS 6
#define AEGIS256_KEY_SIZE 32
#define AEGIS256_MIN_AUTH_SIZE 8
#define AEGIS256_MAX_AUTH_SIZE 16

struct aegis_state {
	union aegis_block blocks[AEGIS256_STATE_BLOCKS];
};

struct aegis_ctx {
	union aegis_block key[AEGIS256_KEY_SIZE / AEGIS_BLOCK_SIZE];
};

struct aegis256_ops {
	int (*skcipher_walk_init)(struct skcipher_walk *walk,
				  struct aead_request *req, bool atomic);

	void (*crypt_chunk)(struct aegis_state *state, u8 *dst,
			    const u8 *src, unsigned int size);
};

static void crypto_aegis256_update(struct aegis_state *state)
{
	union aegis_block tmp;
	unsigned int i;

	tmp = state->blocks[AEGIS256_STATE_BLOCKS - 1];
	for (i = AEGIS256_STATE_BLOCKS - 1; i > 0; i--)
		crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1],
				    &state->blocks[i]);
	crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]);
}

static void crypto_aegis256_update_a(struct aegis_state *state,
				     const union aegis_block *msg)
{
	crypto_aegis256_update(state);
	crypto_aegis_block_xor(&state->blocks[0], msg);
}

static void crypto_aegis256_update_u(struct aegis_state *state, const void *msg)
{
	crypto_aegis256_update(state);
	crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
}

static void crypto_aegis256_init(struct aegis_state *state,
				 const union aegis_block *key,
				 const u8 *iv)
{
	union aegis_block key_iv[2];
	unsigned int i;

	key_iv[0] = key[0];
	key_iv[1] = key[1];
	crypto_xor(key_iv[0].bytes, iv + 0 * AEGIS_BLOCK_SIZE,
			AEGIS_BLOCK_SIZE);
	crypto_xor(key_iv[1].bytes, iv + 1 * AEGIS_BLOCK_SIZE,
			AEGIS_BLOCK_SIZE);

	state->blocks[0] = key_iv[0];
	state->blocks[1] = key_iv[1];
	state->blocks[2] = crypto_aegis_const[1];
	state->blocks[3] = crypto_aegis_const[0];
	state->blocks[4] = key[0];
	state->blocks[5] = key[1];

	crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[0]);
	crypto_aegis_block_xor(&state->blocks[5], &crypto_aegis_const[1]);

	for (i = 0; i < 4; i++) {
		crypto_aegis256_update_a(state, &key[0]);
		crypto_aegis256_update_a(state, &key[1]);
		crypto_aegis256_update_a(state, &key_iv[0]);
		crypto_aegis256_update_a(state, &key_iv[1]);
	}
}

static void crypto_aegis256_ad(struct aegis_state *state,
			       const u8 *src, unsigned int size)
{
	if (AEGIS_ALIGNED(src)) {
		const union aegis_block *src_blk =
				(const union aegis_block *)src;

		while (size >= AEGIS_BLOCK_SIZE) {
			crypto_aegis256_update_a(state, src_blk);

			size -= AEGIS_BLOCK_SIZE;
			src_blk++;
		}
	} else {
		while (size >= AEGIS_BLOCK_SIZE) {
			crypto_aegis256_update_u(state, src);

			size -= AEGIS_BLOCK_SIZE;
			src += AEGIS_BLOCK_SIZE;
		}
	}
}

static void crypto_aegis256_encrypt_chunk(struct aegis_state *state, u8 *dst,
					  const u8 *src, unsigned int size)
{
	union aegis_block tmp;

	if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
		while (size >= AEGIS_BLOCK_SIZE) {
			union aegis_block *dst_blk =
					(union aegis_block *)dst;
			const union aegis_block *src_blk =
					(const union aegis_block *)src;

			tmp = state->blocks[2];
			crypto_aegis_block_and(&tmp, &state->blocks[3]);
			crypto_aegis_block_xor(&tmp, &state->blocks[5]);
			crypto_aegis_block_xor(&tmp, &state->blocks[4]);
			crypto_aegis_block_xor(&tmp, &state->blocks[1]);
			crypto_aegis_block_xor(&tmp, src_blk);

			crypto_aegis256_update_a(state, src_blk);

			*dst_blk = tmp;

			size -= AEGIS_BLOCK_SIZE;
			src += AEGIS_BLOCK_SIZE;
			dst += AEGIS_BLOCK_SIZE;
		}
	} else {
		while (size >= AEGIS_BLOCK_SIZE) {
			tmp = state->blocks[2];
			crypto_aegis_block_and(&tmp, &state->blocks[3]);
			crypto_aegis_block_xor(&tmp, &state->blocks[5]);
			crypto_aegis_block_xor(&tmp, &state->blocks[4]);
			crypto_aegis_block_xor(&tmp, &state->blocks[1]);
			crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);

			crypto_aegis256_update_u(state, src);

			memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);

			size -= AEGIS_BLOCK_SIZE;
			src += AEGIS_BLOCK_SIZE;
			dst += AEGIS_BLOCK_SIZE;
		}
	}

	if (size > 0) {
		union aegis_block msg = {};
		memcpy(msg.bytes, src, size);

		tmp = state->blocks[2];
		crypto_aegis_block_and(&tmp, &state->blocks[3]);
		crypto_aegis_block_xor(&tmp, &state->blocks[5]);
		crypto_aegis_block_xor(&tmp, &state->blocks[4]);
		crypto_aegis_block_xor(&tmp, &state->blocks[1]);

		crypto_aegis256_update_a(state, &msg);

		crypto_aegis_block_xor(&msg, &tmp);

		memcpy(dst, msg.bytes, size);
	}
}

static void crypto_aegis256_decrypt_chunk(struct aegis_state *state, u8 *dst,
					  const u8 *src, unsigned int size)
{
	union aegis_block tmp;

	if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
		while (size >= AEGIS_BLOCK_SIZE) {
			union aegis_block *dst_blk =
					(union aegis_block *)dst;
			const union aegis_block *src_blk =
					(const union aegis_block *)src;

			tmp = state->blocks[2];
			crypto_aegis_block_and(&tmp, &state->blocks[3]);
			crypto_aegis_block_xor(&tmp, &state->blocks[5]);
			crypto_aegis_block_xor(&tmp, &state->blocks[4]);
			crypto_aegis_block_xor(&tmp, &state->blocks[1]);
			crypto_aegis_block_xor(&tmp, src_blk);

			crypto_aegis256_update_a(state, &tmp);

			*dst_blk = tmp;

			size -= AEGIS_BLOCK_SIZE;
			src += AEGIS_BLOCK_SIZE;
			dst += AEGIS_BLOCK_SIZE;
		}
	} else {
		while (size >= AEGIS_BLOCK_SIZE) {
			tmp = state->blocks[2];
			crypto_aegis_block_and(&tmp, &state->blocks[3]);
			crypto_aegis_block_xor(&tmp, &state->blocks[5]);
			crypto_aegis_block_xor(&tmp, &state->blocks[4]);
			crypto_aegis_block_xor(&tmp, &state->blocks[1]);
			crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);

			crypto_aegis256_update_a(state, &tmp);

			memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);

			size -= AEGIS_BLOCK_SIZE;
			src += AEGIS_BLOCK_SIZE;
			dst += AEGIS_BLOCK_SIZE;
		}
	}

	if (size > 0) {
		union aegis_block msg = {};
		memcpy(msg.bytes, src, size);

		tmp = state->blocks[2];
		crypto_aegis_block_and(&tmp, &state->blocks[3]);
		crypto_aegis_block_xor(&tmp, &state->blocks[5]);
		crypto_aegis_block_xor(&tmp, &state->blocks[4]);
		crypto_aegis_block_xor(&tmp, &state->blocks[1]);
		crypto_aegis_block_xor(&msg, &tmp);

		memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);

		crypto_aegis256_update_a(state, &msg);

		memcpy(dst, msg.bytes, size);
	}
}

static void crypto_aegis256_process_ad(struct aegis_state *state,
				       struct scatterlist *sg_src,
				       unsigned int assoclen)
{
	struct scatter_walk walk;
	union aegis_block buf;
	unsigned int pos = 0;

	scatterwalk_start(&walk, sg_src);
	while (assoclen != 0) {
		unsigned int size = scatterwalk_clamp(&walk, assoclen);
		unsigned int left = size;
		void *mapped = scatterwalk_map(&walk);
		const u8 *src = (const u8 *)mapped;

		if (pos + size >= AEGIS_BLOCK_SIZE) {
			if (pos > 0) {
				unsigned int fill = AEGIS_BLOCK_SIZE - pos;
				memcpy(buf.bytes + pos, src, fill);
				crypto_aegis256_update_a(state, &buf);
				pos = 0;
				left -= fill;
				src += fill;
			}

			crypto_aegis256_ad(state, src, left);
			src += left & ~(AEGIS_BLOCK_SIZE - 1);
			left &= AEGIS_BLOCK_SIZE - 1;
		}

		memcpy(buf.bytes + pos, src, left);

		pos += left;
		assoclen -= size;
		scatterwalk_unmap(mapped);
		scatterwalk_advance(&walk, size);
		scatterwalk_done(&walk, 0, assoclen);
	}

	if (pos > 0) {
		memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
		crypto_aegis256_update_a(state, &buf);
	}
}

static void crypto_aegis256_process_crypt(struct aegis_state *state,
					  struct aead_request *req,
					  const struct aegis256_ops *ops)
{
	struct skcipher_walk walk;
	u8 *src, *dst;
	unsigned int chunksize;

	ops->skcipher_walk_init(&walk, req, false);

	while (walk.nbytes) {
		src = walk.src.virt.addr;
		dst = walk.dst.virt.addr;
		chunksize = walk.nbytes;

		ops->crypt_chunk(state, dst, src, chunksize);

		skcipher_walk_done(&walk, 0);
	}
}

static void crypto_aegis256_final(struct aegis_state *state,
				  union aegis_block *tag_xor,
				  u64 assoclen, u64 cryptlen)
{
	u64 assocbits = assoclen * 8;
	u64 cryptbits = cryptlen * 8;

	union aegis_block tmp;
	unsigned int i;

	tmp.words64[0] = cpu_to_le64(assocbits);
	tmp.words64[1] = cpu_to_le64(cryptbits);

	crypto_aegis_block_xor(&tmp, &state->blocks[3]);

	for (i = 0; i < 7; i++)
		crypto_aegis256_update_a(state, &tmp);

	for (i = 0; i < AEGIS256_STATE_BLOCKS; i++)
		crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
}

static int crypto_aegis256_setkey(struct crypto_aead *aead, const u8 *key,
				  unsigned int keylen)
{
	struct aegis_ctx *ctx = crypto_aead_ctx(aead);

	if (keylen != AEGIS256_KEY_SIZE) {
		crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}

	memcpy(ctx->key[0].bytes, key, AEGIS_BLOCK_SIZE);
	memcpy(ctx->key[1].bytes, key + AEGIS_BLOCK_SIZE,
			AEGIS_BLOCK_SIZE);
	return 0;
}

static int crypto_aegis256_setauthsize(struct crypto_aead *tfm,
				       unsigned int authsize)
{
	if (authsize > AEGIS256_MAX_AUTH_SIZE)
		return -EINVAL;
	if (authsize < AEGIS256_MIN_AUTH_SIZE)
		return -EINVAL;
	return 0;
}

static void crypto_aegis256_crypt(struct aead_request *req,
				  union aegis_block *tag_xor,
				  unsigned int cryptlen,
				  const struct aegis256_ops *ops)
{
	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
	struct aegis_state state;

	crypto_aegis256_init(&state, ctx->key, req->iv);
	crypto_aegis256_process_ad(&state, req->src, req->assoclen);
	crypto_aegis256_process_crypt(&state, req, ops);
	crypto_aegis256_final(&state, tag_xor, req->assoclen, cryptlen);
}

static int crypto_aegis256_encrypt(struct aead_request *req)
{
	static const struct aegis256_ops ops = {
		.skcipher_walk_init = skcipher_walk_aead_encrypt,
		.crypt_chunk = crypto_aegis256_encrypt_chunk,
	};

	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	union aegis_block tag = {};
	unsigned int authsize = crypto_aead_authsize(tfm);
	unsigned int cryptlen = req->cryptlen;

	crypto_aegis256_crypt(req, &tag, cryptlen, &ops);

	scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
				 authsize, 1);
	return 0;
}

static int crypto_aegis256_decrypt(struct aead_request *req)
{
	static const struct aegis256_ops ops = {
		.skcipher_walk_init = skcipher_walk_aead_decrypt,
		.crypt_chunk = crypto_aegis256_decrypt_chunk,
	};
	static const u8 zeros[AEGIS256_MAX_AUTH_SIZE] = {};

	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	union aegis_block tag;
	unsigned int authsize = crypto_aead_authsize(tfm);
	unsigned int cryptlen = req->cryptlen - authsize;

	scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
				 authsize, 0);

	crypto_aegis256_crypt(req, &tag, cryptlen, &ops);

	return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
}

static int crypto_aegis256_init_tfm(struct crypto_aead *tfm)
{
	return 0;
}

static void crypto_aegis256_exit_tfm(struct crypto_aead *tfm)
{
}

static struct aead_alg crypto_aegis256_alg = {
	.setkey = crypto_aegis256_setkey,
	.setauthsize = crypto_aegis256_setauthsize,
	.encrypt = crypto_aegis256_encrypt,
	.decrypt = crypto_aegis256_decrypt,
	.init = crypto_aegis256_init_tfm,
	.exit = crypto_aegis256_exit_tfm,

	.ivsize = AEGIS256_NONCE_SIZE,
	.maxauthsize = AEGIS256_MAX_AUTH_SIZE,
	.chunksize = AEGIS_BLOCK_SIZE,

	.base = {
		.cra_blocksize = 1,
		.cra_ctxsize = sizeof(struct aegis_ctx),
		.cra_alignmask = 0,

		.cra_priority = 100,

		.cra_name = "aegis256",
		.cra_driver_name = "aegis256-generic",

		.cra_module = THIS_MODULE,
	}
};

static int __init crypto_aegis256_module_init(void)
{
	return crypto_register_aead(&crypto_aegis256_alg);
}

static void __exit crypto_aegis256_module_exit(void)
{
	crypto_unregister_aead(&crypto_aegis256_alg);
}

module_init(crypto_aegis256_module_init);
module_exit(crypto_aegis256_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
MODULE_DESCRIPTION("AEGIS-256 AEAD algorithm");
MODULE_ALIAS_CRYPTO("aegis256");
MODULE_ALIAS_CRYPTO("aegis256-generic");