1 /*
2 * The AEGIS-128 Authenticated-Encryption Algorithm
3 *
4 * Copyright (c) 2017-2018 Ondrej Mosnacek <omosnacek@gmail.com>
5 * Copyright (C) 2017-2018 Red Hat, Inc. All rights reserved.
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; either version 2 of the License, or (at your option)
10 * any later version.
11 */
12
13 #include <crypto/algapi.h>
14 #include <crypto/internal/aead.h>
15 #include <crypto/internal/skcipher.h>
16 #include <crypto/scatterwalk.h>
17 #include <linux/err.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/scatterlist.h>
22
23 #include "aegis.h"
24
25 #define AEGIS128_NONCE_SIZE 16
26 #define AEGIS128_STATE_BLOCKS 5
27 #define AEGIS128_KEY_SIZE 16
28 #define AEGIS128_MIN_AUTH_SIZE 8
29 #define AEGIS128_MAX_AUTH_SIZE 16
30
31 struct aegis_state {
32 union aegis_block blocks[AEGIS128_STATE_BLOCKS];
33 };
34
35 struct aegis_ctx {
36 union aegis_block key;
37 };
38
39 struct aegis128_ops {
40 int (*skcipher_walk_init)(struct skcipher_walk *walk,
41 struct aead_request *req, bool atomic);
42
43 void (*crypt_chunk)(struct aegis_state *state, u8 *dst,
44 const u8 *src, unsigned int size);
45 };
46
crypto_aegis128_update(struct aegis_state * state)47 static void crypto_aegis128_update(struct aegis_state *state)
48 {
49 union aegis_block tmp;
50 unsigned int i;
51
52 tmp = state->blocks[AEGIS128_STATE_BLOCKS - 1];
53 for (i = AEGIS128_STATE_BLOCKS - 1; i > 0; i--)
54 crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1],
55 &state->blocks[i]);
56 crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]);
57 }
58
crypto_aegis128_update_a(struct aegis_state * state,const union aegis_block * msg)59 static void crypto_aegis128_update_a(struct aegis_state *state,
60 const union aegis_block *msg)
61 {
62 crypto_aegis128_update(state);
63 crypto_aegis_block_xor(&state->blocks[0], msg);
64 }
65
crypto_aegis128_update_u(struct aegis_state * state,const void * msg)66 static void crypto_aegis128_update_u(struct aegis_state *state, const void *msg)
67 {
68 crypto_aegis128_update(state);
69 crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
70 }
71
crypto_aegis128_init(struct aegis_state * state,const union aegis_block * key,const u8 * iv)72 static void crypto_aegis128_init(struct aegis_state *state,
73 const union aegis_block *key,
74 const u8 *iv)
75 {
76 union aegis_block key_iv;
77 unsigned int i;
78
79 key_iv = *key;
80 crypto_xor(key_iv.bytes, iv, AEGIS_BLOCK_SIZE);
81
82 state->blocks[0] = key_iv;
83 state->blocks[1] = crypto_aegis_const[1];
84 state->blocks[2] = crypto_aegis_const[0];
85 state->blocks[3] = *key;
86 state->blocks[4] = *key;
87
88 crypto_aegis_block_xor(&state->blocks[3], &crypto_aegis_const[0]);
89 crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[1]);
90
91 for (i = 0; i < 5; i++) {
92 crypto_aegis128_update_a(state, key);
93 crypto_aegis128_update_a(state, &key_iv);
94 }
95 }
96
crypto_aegis128_ad(struct aegis_state * state,const u8 * src,unsigned int size)97 static void crypto_aegis128_ad(struct aegis_state *state,
98 const u8 *src, unsigned int size)
99 {
100 if (AEGIS_ALIGNED(src)) {
101 const union aegis_block *src_blk =
102 (const union aegis_block *)src;
103
104 while (size >= AEGIS_BLOCK_SIZE) {
105 crypto_aegis128_update_a(state, src_blk);
106
107 size -= AEGIS_BLOCK_SIZE;
108 src_blk++;
109 }
110 } else {
111 while (size >= AEGIS_BLOCK_SIZE) {
112 crypto_aegis128_update_u(state, src);
113
114 size -= AEGIS_BLOCK_SIZE;
115 src += AEGIS_BLOCK_SIZE;
116 }
117 }
118 }
119
crypto_aegis128_encrypt_chunk(struct aegis_state * state,u8 * dst,const u8 * src,unsigned int size)120 static void crypto_aegis128_encrypt_chunk(struct aegis_state *state, u8 *dst,
121 const u8 *src, unsigned int size)
122 {
123 union aegis_block tmp;
124
125 if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
126 while (size >= AEGIS_BLOCK_SIZE) {
127 union aegis_block *dst_blk =
128 (union aegis_block *)dst;
129 const union aegis_block *src_blk =
130 (const union aegis_block *)src;
131
132 tmp = state->blocks[2];
133 crypto_aegis_block_and(&tmp, &state->blocks[3]);
134 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
135 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
136 crypto_aegis_block_xor(&tmp, src_blk);
137
138 crypto_aegis128_update_a(state, src_blk);
139
140 *dst_blk = tmp;
141
142 size -= AEGIS_BLOCK_SIZE;
143 src += AEGIS_BLOCK_SIZE;
144 dst += AEGIS_BLOCK_SIZE;
145 }
146 } else {
147 while (size >= AEGIS_BLOCK_SIZE) {
148 tmp = state->blocks[2];
149 crypto_aegis_block_and(&tmp, &state->blocks[3]);
150 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
151 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
152 crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
153
154 crypto_aegis128_update_u(state, src);
155
156 memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
157
158 size -= AEGIS_BLOCK_SIZE;
159 src += AEGIS_BLOCK_SIZE;
160 dst += AEGIS_BLOCK_SIZE;
161 }
162 }
163
164 if (size > 0) {
165 union aegis_block msg = {};
166 memcpy(msg.bytes, src, size);
167
168 tmp = state->blocks[2];
169 crypto_aegis_block_and(&tmp, &state->blocks[3]);
170 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
171 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
172
173 crypto_aegis128_update_a(state, &msg);
174
175 crypto_aegis_block_xor(&msg, &tmp);
176
177 memcpy(dst, msg.bytes, size);
178 }
179 }
180
crypto_aegis128_decrypt_chunk(struct aegis_state * state,u8 * dst,const u8 * src,unsigned int size)181 static void crypto_aegis128_decrypt_chunk(struct aegis_state *state, u8 *dst,
182 const u8 *src, unsigned int size)
183 {
184 union aegis_block tmp;
185
186 if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
187 while (size >= AEGIS_BLOCK_SIZE) {
188 union aegis_block *dst_blk =
189 (union aegis_block *)dst;
190 const union aegis_block *src_blk =
191 (const union aegis_block *)src;
192
193 tmp = state->blocks[2];
194 crypto_aegis_block_and(&tmp, &state->blocks[3]);
195 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
196 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
197 crypto_aegis_block_xor(&tmp, src_blk);
198
199 crypto_aegis128_update_a(state, &tmp);
200
201 *dst_blk = tmp;
202
203 size -= AEGIS_BLOCK_SIZE;
204 src += AEGIS_BLOCK_SIZE;
205 dst += AEGIS_BLOCK_SIZE;
206 }
207 } else {
208 while (size >= AEGIS_BLOCK_SIZE) {
209 tmp = state->blocks[2];
210 crypto_aegis_block_and(&tmp, &state->blocks[3]);
211 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
212 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
213 crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
214
215 crypto_aegis128_update_a(state, &tmp);
216
217 memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
218
219 size -= AEGIS_BLOCK_SIZE;
220 src += AEGIS_BLOCK_SIZE;
221 dst += AEGIS_BLOCK_SIZE;
222 }
223 }
224
225 if (size > 0) {
226 union aegis_block msg = {};
227 memcpy(msg.bytes, src, size);
228
229 tmp = state->blocks[2];
230 crypto_aegis_block_and(&tmp, &state->blocks[3]);
231 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
232 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
233 crypto_aegis_block_xor(&msg, &tmp);
234
235 memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);
236
237 crypto_aegis128_update_a(state, &msg);
238
239 memcpy(dst, msg.bytes, size);
240 }
241 }
242
crypto_aegis128_process_ad(struct aegis_state * state,struct scatterlist * sg_src,unsigned int assoclen)243 static void crypto_aegis128_process_ad(struct aegis_state *state,
244 struct scatterlist *sg_src,
245 unsigned int assoclen)
246 {
247 struct scatter_walk walk;
248 union aegis_block buf;
249 unsigned int pos = 0;
250
251 scatterwalk_start(&walk, sg_src);
252 while (assoclen != 0) {
253 unsigned int size = scatterwalk_clamp(&walk, assoclen);
254 unsigned int left = size;
255 void *mapped = scatterwalk_map(&walk);
256 const u8 *src = (const u8 *)mapped;
257
258 if (pos + size >= AEGIS_BLOCK_SIZE) {
259 if (pos > 0) {
260 unsigned int fill = AEGIS_BLOCK_SIZE - pos;
261 memcpy(buf.bytes + pos, src, fill);
262 crypto_aegis128_update_a(state, &buf);
263 pos = 0;
264 left -= fill;
265 src += fill;
266 }
267
268 crypto_aegis128_ad(state, src, left);
269 src += left & ~(AEGIS_BLOCK_SIZE - 1);
270 left &= AEGIS_BLOCK_SIZE - 1;
271 }
272
273 memcpy(buf.bytes + pos, src, left);
274
275 pos += left;
276 assoclen -= size;
277 scatterwalk_unmap(mapped);
278 scatterwalk_advance(&walk, size);
279 scatterwalk_done(&walk, 0, assoclen);
280 }
281
282 if (pos > 0) {
283 memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
284 crypto_aegis128_update_a(state, &buf);
285 }
286 }
287
crypto_aegis128_process_crypt(struct aegis_state * state,struct aead_request * req,const struct aegis128_ops * ops)288 static void crypto_aegis128_process_crypt(struct aegis_state *state,
289 struct aead_request *req,
290 const struct aegis128_ops *ops)
291 {
292 struct skcipher_walk walk;
293 u8 *src, *dst;
294 unsigned int chunksize;
295
296 ops->skcipher_walk_init(&walk, req, false);
297
298 while (walk.nbytes) {
299 src = walk.src.virt.addr;
300 dst = walk.dst.virt.addr;
301 chunksize = walk.nbytes;
302
303 ops->crypt_chunk(state, dst, src, chunksize);
304
305 skcipher_walk_done(&walk, 0);
306 }
307 }
308
crypto_aegis128_final(struct aegis_state * state,union aegis_block * tag_xor,u64 assoclen,u64 cryptlen)309 static void crypto_aegis128_final(struct aegis_state *state,
310 union aegis_block *tag_xor,
311 u64 assoclen, u64 cryptlen)
312 {
313 u64 assocbits = assoclen * 8;
314 u64 cryptbits = cryptlen * 8;
315
316 union aegis_block tmp;
317 unsigned int i;
318
319 tmp.words64[0] = cpu_to_le64(assocbits);
320 tmp.words64[1] = cpu_to_le64(cryptbits);
321
322 crypto_aegis_block_xor(&tmp, &state->blocks[3]);
323
324 for (i = 0; i < 7; i++)
325 crypto_aegis128_update_a(state, &tmp);
326
327 for (i = 0; i < AEGIS128_STATE_BLOCKS; i++)
328 crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
329 }
330
crypto_aegis128_setkey(struct crypto_aead * aead,const u8 * key,unsigned int keylen)331 static int crypto_aegis128_setkey(struct crypto_aead *aead, const u8 *key,
332 unsigned int keylen)
333 {
334 struct aegis_ctx *ctx = crypto_aead_ctx(aead);
335
336 if (keylen != AEGIS128_KEY_SIZE) {
337 crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
338 return -EINVAL;
339 }
340
341 memcpy(ctx->key.bytes, key, AEGIS128_KEY_SIZE);
342 return 0;
343 }
344
crypto_aegis128_setauthsize(struct crypto_aead * tfm,unsigned int authsize)345 static int crypto_aegis128_setauthsize(struct crypto_aead *tfm,
346 unsigned int authsize)
347 {
348 if (authsize > AEGIS128_MAX_AUTH_SIZE)
349 return -EINVAL;
350 if (authsize < AEGIS128_MIN_AUTH_SIZE)
351 return -EINVAL;
352 return 0;
353 }
354
crypto_aegis128_crypt(struct aead_request * req,union aegis_block * tag_xor,unsigned int cryptlen,const struct aegis128_ops * ops)355 static void crypto_aegis128_crypt(struct aead_request *req,
356 union aegis_block *tag_xor,
357 unsigned int cryptlen,
358 const struct aegis128_ops *ops)
359 {
360 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
361 struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
362 struct aegis_state state;
363
364 crypto_aegis128_init(&state, &ctx->key, req->iv);
365 crypto_aegis128_process_ad(&state, req->src, req->assoclen);
366 crypto_aegis128_process_crypt(&state, req, ops);
367 crypto_aegis128_final(&state, tag_xor, req->assoclen, cryptlen);
368 }
369
crypto_aegis128_encrypt(struct aead_request * req)370 static int crypto_aegis128_encrypt(struct aead_request *req)
371 {
372 static const struct aegis128_ops ops = {
373 .skcipher_walk_init = skcipher_walk_aead_encrypt,
374 .crypt_chunk = crypto_aegis128_encrypt_chunk,
375 };
376
377 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
378 union aegis_block tag = {};
379 unsigned int authsize = crypto_aead_authsize(tfm);
380 unsigned int cryptlen = req->cryptlen;
381
382 crypto_aegis128_crypt(req, &tag, cryptlen, &ops);
383
384 scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
385 authsize, 1);
386 return 0;
387 }
388
crypto_aegis128_decrypt(struct aead_request * req)389 static int crypto_aegis128_decrypt(struct aead_request *req)
390 {
391 static const struct aegis128_ops ops = {
392 .skcipher_walk_init = skcipher_walk_aead_decrypt,
393 .crypt_chunk = crypto_aegis128_decrypt_chunk,
394 };
395 static const u8 zeros[AEGIS128_MAX_AUTH_SIZE] = {};
396
397 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
398 union aegis_block tag;
399 unsigned int authsize = crypto_aead_authsize(tfm);
400 unsigned int cryptlen = req->cryptlen - authsize;
401
402 scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
403 authsize, 0);
404
405 crypto_aegis128_crypt(req, &tag, cryptlen, &ops);
406
407 return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
408 }
409
crypto_aegis128_init_tfm(struct crypto_aead * tfm)410 static int crypto_aegis128_init_tfm(struct crypto_aead *tfm)
411 {
412 return 0;
413 }
414
crypto_aegis128_exit_tfm(struct crypto_aead * tfm)415 static void crypto_aegis128_exit_tfm(struct crypto_aead *tfm)
416 {
417 }
418
419 static struct aead_alg crypto_aegis128_alg = {
420 .setkey = crypto_aegis128_setkey,
421 .setauthsize = crypto_aegis128_setauthsize,
422 .encrypt = crypto_aegis128_encrypt,
423 .decrypt = crypto_aegis128_decrypt,
424 .init = crypto_aegis128_init_tfm,
425 .exit = crypto_aegis128_exit_tfm,
426
427 .ivsize = AEGIS128_NONCE_SIZE,
428 .maxauthsize = AEGIS128_MAX_AUTH_SIZE,
429 .chunksize = AEGIS_BLOCK_SIZE,
430
431 .base = {
432 .cra_blocksize = 1,
433 .cra_ctxsize = sizeof(struct aegis_ctx),
434 .cra_alignmask = 0,
435
436 .cra_priority = 100,
437
438 .cra_name = "aegis128",
439 .cra_driver_name = "aegis128-generic",
440
441 .cra_module = THIS_MODULE,
442 }
443 };
444
crypto_aegis128_module_init(void)445 static int __init crypto_aegis128_module_init(void)
446 {
447 return crypto_register_aead(&crypto_aegis128_alg);
448 }
449
crypto_aegis128_module_exit(void)450 static void __exit crypto_aegis128_module_exit(void)
451 {
452 crypto_unregister_aead(&crypto_aegis128_alg);
453 }
454
455 module_init(crypto_aegis128_module_init);
456 module_exit(crypto_aegis128_module_exit);
457
458 MODULE_LICENSE("GPL");
459 MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
460 MODULE_DESCRIPTION("AEGIS-128 AEAD algorithm");
461 MODULE_ALIAS_CRYPTO("aegis128");
462 MODULE_ALIAS_CRYPTO("aegis128-generic");
463
