drm: Begin an API for in-kernel clients
[linux-2.6-microblaze.git] / crypto / aegis256.c
1 /*
2  * The AEGIS-256 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 AEGIS256_NONCE_SIZE 32
26 #define AEGIS256_STATE_BLOCKS 6
27 #define AEGIS256_KEY_SIZE 32
28 #define AEGIS256_MIN_AUTH_SIZE 8
29 #define AEGIS256_MAX_AUTH_SIZE 16
30
31 struct aegis_state {
32         union aegis_block blocks[AEGIS256_STATE_BLOCKS];
33 };
34
35 struct aegis_ctx {
36         union aegis_block key[AEGIS256_KEY_SIZE / AEGIS_BLOCK_SIZE];
37 };
38
39 struct aegis256_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
47 static void crypto_aegis256_update(struct aegis_state *state)
48 {
49         union aegis_block tmp;
50         unsigned int i;
51
52         tmp = state->blocks[AEGIS256_STATE_BLOCKS - 1];
53         for (i = AEGIS256_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
59 static void crypto_aegis256_update_a(struct aegis_state *state,
60                                      const union aegis_block *msg)
61 {
62         crypto_aegis256_update(state);
63         crypto_aegis_block_xor(&state->blocks[0], msg);
64 }
65
66 static void crypto_aegis256_update_u(struct aegis_state *state, const void *msg)
67 {
68         crypto_aegis256_update(state);
69         crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
70 }
71
72 static void crypto_aegis256_init(struct aegis_state *state,
73                                  const union aegis_block *key,
74                                  const u8 *iv)
75 {
76         union aegis_block key_iv[2];
77         unsigned int i;
78
79         key_iv[0] = key[0];
80         key_iv[1] = key[1];
81         crypto_xor(key_iv[0].bytes, iv + 0 * AEGIS_BLOCK_SIZE,
82                         AEGIS_BLOCK_SIZE);
83         crypto_xor(key_iv[1].bytes, iv + 1 * AEGIS_BLOCK_SIZE,
84                         AEGIS_BLOCK_SIZE);
85
86         state->blocks[0] = key_iv[0];
87         state->blocks[1] = key_iv[1];
88         state->blocks[2] = crypto_aegis_const[1];
89         state->blocks[3] = crypto_aegis_const[0];
90         state->blocks[4] = key[0];
91         state->blocks[5] = key[1];
92
93         crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[0]);
94         crypto_aegis_block_xor(&state->blocks[5], &crypto_aegis_const[1]);
95
96         for (i = 0; i < 4; i++) {
97                 crypto_aegis256_update_a(state, &key[0]);
98                 crypto_aegis256_update_a(state, &key[1]);
99                 crypto_aegis256_update_a(state, &key_iv[0]);
100                 crypto_aegis256_update_a(state, &key_iv[1]);
101         }
102 }
103
104 static void crypto_aegis256_ad(struct aegis_state *state,
105                                const u8 *src, unsigned int size)
106 {
107         if (AEGIS_ALIGNED(src)) {
108                 const union aegis_block *src_blk =
109                                 (const union aegis_block *)src;
110
111                 while (size >= AEGIS_BLOCK_SIZE) {
112                         crypto_aegis256_update_a(state, src_blk);
113
114                         size -= AEGIS_BLOCK_SIZE;
115                         src_blk++;
116                 }
117         } else {
118                 while (size >= AEGIS_BLOCK_SIZE) {
119                         crypto_aegis256_update_u(state, src);
120
121                         size -= AEGIS_BLOCK_SIZE;
122                         src += AEGIS_BLOCK_SIZE;
123                 }
124         }
125 }
126
127 static void crypto_aegis256_encrypt_chunk(struct aegis_state *state, u8 *dst,
128                                           const u8 *src, unsigned int size)
129 {
130         union aegis_block tmp;
131
132         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
133                 while (size >= AEGIS_BLOCK_SIZE) {
134                         union aegis_block *dst_blk =
135                                         (union aegis_block *)dst;
136                         const union aegis_block *src_blk =
137                                         (const union aegis_block *)src;
138
139                         tmp = state->blocks[2];
140                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
141                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
142                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
143                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
144                         crypto_aegis_block_xor(&tmp, src_blk);
145
146                         crypto_aegis256_update_a(state, src_blk);
147
148                         *dst_blk = tmp;
149
150                         size -= AEGIS_BLOCK_SIZE;
151                         src += AEGIS_BLOCK_SIZE;
152                         dst += AEGIS_BLOCK_SIZE;
153                 }
154         } else {
155                 while (size >= AEGIS_BLOCK_SIZE) {
156                         tmp = state->blocks[2];
157                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
158                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
159                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
160                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
161                         crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
162
163                         crypto_aegis256_update_u(state, src);
164
165                         memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
166
167                         size -= AEGIS_BLOCK_SIZE;
168                         src += AEGIS_BLOCK_SIZE;
169                         dst += AEGIS_BLOCK_SIZE;
170                 }
171         }
172
173         if (size > 0) {
174                 union aegis_block msg = {};
175                 memcpy(msg.bytes, src, size);
176
177                 tmp = state->blocks[2];
178                 crypto_aegis_block_and(&tmp, &state->blocks[3]);
179                 crypto_aegis_block_xor(&tmp, &state->blocks[5]);
180                 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
181                 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
182
183                 crypto_aegis256_update_a(state, &msg);
184
185                 crypto_aegis_block_xor(&msg, &tmp);
186
187                 memcpy(dst, msg.bytes, size);
188         }
189 }
190
191 static void crypto_aegis256_decrypt_chunk(struct aegis_state *state, u8 *dst,
192                                           const u8 *src, unsigned int size)
193 {
194         union aegis_block tmp;
195
196         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
197                 while (size >= AEGIS_BLOCK_SIZE) {
198                         union aegis_block *dst_blk =
199                                         (union aegis_block *)dst;
200                         const union aegis_block *src_blk =
201                                         (const union aegis_block *)src;
202
203                         tmp = state->blocks[2];
204                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
205                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
206                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
207                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
208                         crypto_aegis_block_xor(&tmp, src_blk);
209
210                         crypto_aegis256_update_a(state, &tmp);
211
212                         *dst_blk = tmp;
213
214                         size -= AEGIS_BLOCK_SIZE;
215                         src += AEGIS_BLOCK_SIZE;
216                         dst += AEGIS_BLOCK_SIZE;
217                 }
218         } else {
219                 while (size >= AEGIS_BLOCK_SIZE) {
220                         tmp = state->blocks[2];
221                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
222                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
223                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
224                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
225                         crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
226
227                         crypto_aegis256_update_a(state, &tmp);
228
229                         memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
230
231                         size -= AEGIS_BLOCK_SIZE;
232                         src += AEGIS_BLOCK_SIZE;
233                         dst += AEGIS_BLOCK_SIZE;
234                 }
235         }
236
237         if (size > 0) {
238                 union aegis_block msg = {};
239                 memcpy(msg.bytes, src, size);
240
241                 tmp = state->blocks[2];
242                 crypto_aegis_block_and(&tmp, &state->blocks[3]);
243                 crypto_aegis_block_xor(&tmp, &state->blocks[5]);
244                 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
245                 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
246                 crypto_aegis_block_xor(&msg, &tmp);
247
248                 memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);
249
250                 crypto_aegis256_update_a(state, &msg);
251
252                 memcpy(dst, msg.bytes, size);
253         }
254 }
255
256 static void crypto_aegis256_process_ad(struct aegis_state *state,
257                                        struct scatterlist *sg_src,
258                                        unsigned int assoclen)
259 {
260         struct scatter_walk walk;
261         union aegis_block buf;
262         unsigned int pos = 0;
263
264         scatterwalk_start(&walk, sg_src);
265         while (assoclen != 0) {
266                 unsigned int size = scatterwalk_clamp(&walk, assoclen);
267                 unsigned int left = size;
268                 void *mapped = scatterwalk_map(&walk);
269                 const u8 *src = (const u8 *)mapped;
270
271                 if (pos + size >= AEGIS_BLOCK_SIZE) {
272                         if (pos > 0) {
273                                 unsigned int fill = AEGIS_BLOCK_SIZE - pos;
274                                 memcpy(buf.bytes + pos, src, fill);
275                                 crypto_aegis256_update_a(state, &buf);
276                                 pos = 0;
277                                 left -= fill;
278                                 src += fill;
279                         }
280
281                         crypto_aegis256_ad(state, src, left);
282                         src += left & ~(AEGIS_BLOCK_SIZE - 1);
283                         left &= AEGIS_BLOCK_SIZE - 1;
284                 }
285
286                 memcpy(buf.bytes + pos, src, left);
287
288                 pos += left;
289                 assoclen -= size;
290                 scatterwalk_unmap(mapped);
291                 scatterwalk_advance(&walk, size);
292                 scatterwalk_done(&walk, 0, assoclen);
293         }
294
295         if (pos > 0) {
296                 memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
297                 crypto_aegis256_update_a(state, &buf);
298         }
299 }
300
301 static void crypto_aegis256_process_crypt(struct aegis_state *state,
302                                           struct aead_request *req,
303                                           const struct aegis256_ops *ops)
304 {
305         struct skcipher_walk walk;
306         u8 *src, *dst;
307         unsigned int chunksize;
308
309         ops->skcipher_walk_init(&walk, req, false);
310
311         while (walk.nbytes) {
312                 src = walk.src.virt.addr;
313                 dst = walk.dst.virt.addr;
314                 chunksize = walk.nbytes;
315
316                 ops->crypt_chunk(state, dst, src, chunksize);
317
318                 skcipher_walk_done(&walk, 0);
319         }
320 }
321
322 static void crypto_aegis256_final(struct aegis_state *state,
323                                   union aegis_block *tag_xor,
324                                   u64 assoclen, u64 cryptlen)
325 {
326         u64 assocbits = assoclen * 8;
327         u64 cryptbits = cryptlen * 8;
328
329         union aegis_block tmp;
330         unsigned int i;
331
332         tmp.words64[0] = cpu_to_le64(assocbits);
333         tmp.words64[1] = cpu_to_le64(cryptbits);
334
335         crypto_aegis_block_xor(&tmp, &state->blocks[3]);
336
337         for (i = 0; i < 7; i++)
338                 crypto_aegis256_update_a(state, &tmp);
339
340         for (i = 0; i < AEGIS256_STATE_BLOCKS; i++)
341                 crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
342 }
343
344 static int crypto_aegis256_setkey(struct crypto_aead *aead, const u8 *key,
345                                   unsigned int keylen)
346 {
347         struct aegis_ctx *ctx = crypto_aead_ctx(aead);
348
349         if (keylen != AEGIS256_KEY_SIZE) {
350                 crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
351                 return -EINVAL;
352         }
353
354         memcpy(ctx->key[0].bytes, key, AEGIS_BLOCK_SIZE);
355         memcpy(ctx->key[1].bytes, key + AEGIS_BLOCK_SIZE,
356                         AEGIS_BLOCK_SIZE);
357         return 0;
358 }
359
360 static int crypto_aegis256_setauthsize(struct crypto_aead *tfm,
361                                        unsigned int authsize)
362 {
363         if (authsize > AEGIS256_MAX_AUTH_SIZE)
364                 return -EINVAL;
365         if (authsize < AEGIS256_MIN_AUTH_SIZE)
366                 return -EINVAL;
367         return 0;
368 }
369
370 static void crypto_aegis256_crypt(struct aead_request *req,
371                                   union aegis_block *tag_xor,
372                                   unsigned int cryptlen,
373                                   const struct aegis256_ops *ops)
374 {
375         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
376         struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
377         struct aegis_state state;
378
379         crypto_aegis256_init(&state, ctx->key, req->iv);
380         crypto_aegis256_process_ad(&state, req->src, req->assoclen);
381         crypto_aegis256_process_crypt(&state, req, ops);
382         crypto_aegis256_final(&state, tag_xor, req->assoclen, cryptlen);
383 }
384
385 static int crypto_aegis256_encrypt(struct aead_request *req)
386 {
387         static const struct aegis256_ops ops = {
388                 .skcipher_walk_init = skcipher_walk_aead_encrypt,
389                 .crypt_chunk = crypto_aegis256_encrypt_chunk,
390         };
391
392         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
393         union aegis_block tag = {};
394         unsigned int authsize = crypto_aead_authsize(tfm);
395         unsigned int cryptlen = req->cryptlen;
396
397         crypto_aegis256_crypt(req, &tag, cryptlen, &ops);
398
399         scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
400                                  authsize, 1);
401         return 0;
402 }
403
404 static int crypto_aegis256_decrypt(struct aead_request *req)
405 {
406         static const struct aegis256_ops ops = {
407                 .skcipher_walk_init = skcipher_walk_aead_decrypt,
408                 .crypt_chunk = crypto_aegis256_decrypt_chunk,
409         };
410         static const u8 zeros[AEGIS256_MAX_AUTH_SIZE] = {};
411
412         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
413         union aegis_block tag;
414         unsigned int authsize = crypto_aead_authsize(tfm);
415         unsigned int cryptlen = req->cryptlen - authsize;
416
417         scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
418                                  authsize, 0);
419
420         crypto_aegis256_crypt(req, &tag, cryptlen, &ops);
421
422         return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
423 }
424
425 static int crypto_aegis256_init_tfm(struct crypto_aead *tfm)
426 {
427         return 0;
428 }
429
430 static void crypto_aegis256_exit_tfm(struct crypto_aead *tfm)
431 {
432 }
433
434 static struct aead_alg crypto_aegis256_alg = {
435         .setkey = crypto_aegis256_setkey,
436         .setauthsize = crypto_aegis256_setauthsize,
437         .encrypt = crypto_aegis256_encrypt,
438         .decrypt = crypto_aegis256_decrypt,
439         .init = crypto_aegis256_init_tfm,
440         .exit = crypto_aegis256_exit_tfm,
441
442         .ivsize = AEGIS256_NONCE_SIZE,
443         .maxauthsize = AEGIS256_MAX_AUTH_SIZE,
444         .chunksize = AEGIS_BLOCK_SIZE,
445
446         .base = {
447                 .cra_flags = CRYPTO_ALG_TYPE_AEAD,
448                 .cra_blocksize = 1,
449                 .cra_ctxsize = sizeof(struct aegis_ctx),
450                 .cra_alignmask = 0,
451
452                 .cra_priority = 100,
453
454                 .cra_name = "aegis256",
455                 .cra_driver_name = "aegis256-generic",
456
457                 .cra_module = THIS_MODULE,
458         }
459 };
460
461 static int __init crypto_aegis256_module_init(void)
462 {
463         return crypto_register_aead(&crypto_aegis256_alg);
464 }
465
466 static void __exit crypto_aegis256_module_exit(void)
467 {
468         crypto_unregister_aead(&crypto_aegis256_alg);
469 }
470
471 module_init(crypto_aegis256_module_init);
472 module_exit(crypto_aegis256_module_exit);
473
474 MODULE_LICENSE("GPL");
475 MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
476 MODULE_DESCRIPTION("AEGIS-256 AEAD algorithm");
477 MODULE_ALIAS_CRYPTO("aegis256");
478 MODULE_ALIAS_CRYPTO("aegis256-generic");