1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Bit sliced AES using NEON instructions
4 *
5 * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
6 */
7
8 #include <asm/neon.h>
9 #include <asm/simd.h>
10 #include <crypto/aes.h>
11 #include <crypto/ctr.h>
12 #include <crypto/internal/cipher.h>
13 #include <crypto/internal/simd.h>
14 #include <crypto/internal/skcipher.h>
15 #include <crypto/scatterwalk.h>
16 #include <crypto/xts.h>
17 #include <linux/module.h>
18
19 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
20 MODULE_LICENSE("GPL v2");
21
22 MODULE_ALIAS_CRYPTO("ecb(aes)");
23 MODULE_ALIAS_CRYPTO("cbc(aes)-all");
24 MODULE_ALIAS_CRYPTO("ctr(aes)");
25 MODULE_ALIAS_CRYPTO("xts(aes)");
26
27 MODULE_IMPORT_NS(CRYPTO_INTERNAL);
28
29 asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
30
31 asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
32 int rounds, int blocks);
33 asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
34 int rounds, int blocks);
35
36 asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
37 int rounds, int blocks, u8 iv[]);
38
39 asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
40 int rounds, int blocks, u8 ctr[], u8 final[]);
41
42 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
43 int rounds, int blocks, u8 iv[], int);
44 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
45 int rounds, int blocks, u8 iv[], int);
46
47 struct aesbs_ctx {
48 int rounds;
49 u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32] __aligned(AES_BLOCK_SIZE);
50 };
51
52 struct aesbs_cbc_ctx {
53 struct aesbs_ctx key;
54 struct crypto_skcipher *enc_tfm;
55 };
56
57 struct aesbs_xts_ctx {
58 struct aesbs_ctx key;
59 struct crypto_cipher *cts_tfm;
60 struct crypto_cipher *tweak_tfm;
61 };
62
63 struct aesbs_ctr_ctx {
64 struct aesbs_ctx key; /* must be first member */
65 struct crypto_aes_ctx fallback;
66 };
67
aesbs_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)68 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
69 unsigned int key_len)
70 {
71 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
72 struct crypto_aes_ctx rk;
73 int err;
74
75 err = aes_expandkey(&rk, in_key, key_len);
76 if (err)
77 return err;
78
79 ctx->rounds = 6 + key_len / 4;
80
81 kernel_neon_begin();
82 aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
83 kernel_neon_end();
84
85 return 0;
86 }
87
__ecb_crypt(struct skcipher_request * req,void (* fn)(u8 out[],u8 const in[],u8 const rk[],int rounds,int blocks))88 static int __ecb_crypt(struct skcipher_request *req,
89 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
90 int rounds, int blocks))
91 {
92 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
93 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
94 struct skcipher_walk walk;
95 int err;
96
97 err = skcipher_walk_virt(&walk, req, false);
98
99 while (walk.nbytes >= AES_BLOCK_SIZE) {
100 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
101
102 if (walk.nbytes < walk.total)
103 blocks = round_down(blocks,
104 walk.stride / AES_BLOCK_SIZE);
105
106 kernel_neon_begin();
107 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
108 ctx->rounds, blocks);
109 kernel_neon_end();
110 err = skcipher_walk_done(&walk,
111 walk.nbytes - blocks * AES_BLOCK_SIZE);
112 }
113
114 return err;
115 }
116
ecb_encrypt(struct skcipher_request * req)117 static int ecb_encrypt(struct skcipher_request *req)
118 {
119 return __ecb_crypt(req, aesbs_ecb_encrypt);
120 }
121
ecb_decrypt(struct skcipher_request * req)122 static int ecb_decrypt(struct skcipher_request *req)
123 {
124 return __ecb_crypt(req, aesbs_ecb_decrypt);
125 }
126
aesbs_cbc_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)127 static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
128 unsigned int key_len)
129 {
130 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
131 struct crypto_aes_ctx rk;
132 int err;
133
134 err = aes_expandkey(&rk, in_key, key_len);
135 if (err)
136 return err;
137
138 ctx->key.rounds = 6 + key_len / 4;
139
140 kernel_neon_begin();
141 aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
142 kernel_neon_end();
143 memzero_explicit(&rk, sizeof(rk));
144
145 return crypto_skcipher_setkey(ctx->enc_tfm, in_key, key_len);
146 }
147
cbc_encrypt(struct skcipher_request * req)148 static int cbc_encrypt(struct skcipher_request *req)
149 {
150 struct skcipher_request *subreq = skcipher_request_ctx(req);
151 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
152 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
153
154 skcipher_request_set_tfm(subreq, ctx->enc_tfm);
155 skcipher_request_set_callback(subreq,
156 skcipher_request_flags(req),
157 NULL, NULL);
158 skcipher_request_set_crypt(subreq, req->src, req->dst,
159 req->cryptlen, req->iv);
160
161 return crypto_skcipher_encrypt(subreq);
162 }
163
cbc_decrypt(struct skcipher_request * req)164 static int cbc_decrypt(struct skcipher_request *req)
165 {
166 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
167 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
168 struct skcipher_walk walk;
169 int err;
170
171 err = skcipher_walk_virt(&walk, req, false);
172
173 while (walk.nbytes >= AES_BLOCK_SIZE) {
174 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
175
176 if (walk.nbytes < walk.total)
177 blocks = round_down(blocks,
178 walk.stride / AES_BLOCK_SIZE);
179
180 kernel_neon_begin();
181 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
182 ctx->key.rk, ctx->key.rounds, blocks,
183 walk.iv);
184 kernel_neon_end();
185 err = skcipher_walk_done(&walk,
186 walk.nbytes - blocks * AES_BLOCK_SIZE);
187 }
188
189 return err;
190 }
191
cbc_init(struct crypto_skcipher * tfm)192 static int cbc_init(struct crypto_skcipher *tfm)
193 {
194 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
195 unsigned int reqsize;
196
197 ctx->enc_tfm = crypto_alloc_skcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC |
198 CRYPTO_ALG_NEED_FALLBACK);
199 if (IS_ERR(ctx->enc_tfm))
200 return PTR_ERR(ctx->enc_tfm);
201
202 reqsize = sizeof(struct skcipher_request);
203 reqsize += crypto_skcipher_reqsize(ctx->enc_tfm);
204 crypto_skcipher_set_reqsize(tfm, reqsize);
205
206 return 0;
207 }
208
cbc_exit(struct crypto_skcipher * tfm)209 static void cbc_exit(struct crypto_skcipher *tfm)
210 {
211 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
212
213 crypto_free_skcipher(ctx->enc_tfm);
214 }
215
aesbs_ctr_setkey_sync(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)216 static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
217 unsigned int key_len)
218 {
219 struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
220 int err;
221
222 err = aes_expandkey(&ctx->fallback, in_key, key_len);
223 if (err)
224 return err;
225
226 ctx->key.rounds = 6 + key_len / 4;
227
228 kernel_neon_begin();
229 aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
230 kernel_neon_end();
231
232 return 0;
233 }
234
ctr_encrypt(struct skcipher_request * req)235 static int ctr_encrypt(struct skcipher_request *req)
236 {
237 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
238 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
239 struct skcipher_walk walk;
240 u8 buf[AES_BLOCK_SIZE];
241 int err;
242
243 err = skcipher_walk_virt(&walk, req, false);
244
245 while (walk.nbytes > 0) {
246 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
247 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
248
249 if (walk.nbytes < walk.total) {
250 blocks = round_down(blocks,
251 walk.stride / AES_BLOCK_SIZE);
252 final = NULL;
253 }
254
255 kernel_neon_begin();
256 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
257 ctx->rk, ctx->rounds, blocks, walk.iv, final);
258 kernel_neon_end();
259
260 if (final) {
261 u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
262 u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
263
264 crypto_xor_cpy(dst, src, final,
265 walk.total % AES_BLOCK_SIZE);
266
267 err = skcipher_walk_done(&walk, 0);
268 break;
269 }
270 err = skcipher_walk_done(&walk,
271 walk.nbytes - blocks * AES_BLOCK_SIZE);
272 }
273
274 return err;
275 }
276
ctr_encrypt_one(struct crypto_skcipher * tfm,const u8 * src,u8 * dst)277 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
278 {
279 struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
280 unsigned long flags;
281
282 /*
283 * Temporarily disable interrupts to avoid races where
284 * cachelines are evicted when the CPU is interrupted
285 * to do something else.
286 */
287 local_irq_save(flags);
288 aes_encrypt(&ctx->fallback, dst, src);
289 local_irq_restore(flags);
290 }
291
ctr_encrypt_sync(struct skcipher_request * req)292 static int ctr_encrypt_sync(struct skcipher_request *req)
293 {
294 if (!crypto_simd_usable())
295 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
296
297 return ctr_encrypt(req);
298 }
299
aesbs_xts_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)300 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
301 unsigned int key_len)
302 {
303 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
304 int err;
305
306 err = xts_verify_key(tfm, in_key, key_len);
307 if (err)
308 return err;
309
310 key_len /= 2;
311 err = crypto_cipher_setkey(ctx->cts_tfm, in_key, key_len);
312 if (err)
313 return err;
314 err = crypto_cipher_setkey(ctx->tweak_tfm, in_key + key_len, key_len);
315 if (err)
316 return err;
317
318 return aesbs_setkey(tfm, in_key, key_len);
319 }
320
xts_init(struct crypto_skcipher * tfm)321 static int xts_init(struct crypto_skcipher *tfm)
322 {
323 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
324
325 ctx->cts_tfm = crypto_alloc_cipher("aes", 0, 0);
326 if (IS_ERR(ctx->cts_tfm))
327 return PTR_ERR(ctx->cts_tfm);
328
329 ctx->tweak_tfm = crypto_alloc_cipher("aes", 0, 0);
330 if (IS_ERR(ctx->tweak_tfm))
331 crypto_free_cipher(ctx->cts_tfm);
332
333 return PTR_ERR_OR_ZERO(ctx->tweak_tfm);
334 }
335
xts_exit(struct crypto_skcipher * tfm)336 static void xts_exit(struct crypto_skcipher *tfm)
337 {
338 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
339
340 crypto_free_cipher(ctx->tweak_tfm);
341 crypto_free_cipher(ctx->cts_tfm);
342 }
343
__xts_crypt(struct skcipher_request * req,bool encrypt,void (* fn)(u8 out[],u8 const in[],u8 const rk[],int rounds,int blocks,u8 iv[],int))344 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
345 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
346 int rounds, int blocks, u8 iv[], int))
347 {
348 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
349 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
350 int tail = req->cryptlen % AES_BLOCK_SIZE;
351 struct skcipher_request subreq;
352 u8 buf[2 * AES_BLOCK_SIZE];
353 struct skcipher_walk walk;
354 int err;
355
356 if (req->cryptlen < AES_BLOCK_SIZE)
357 return -EINVAL;
358
359 if (unlikely(tail)) {
360 skcipher_request_set_tfm(&subreq, tfm);
361 skcipher_request_set_callback(&subreq,
362 skcipher_request_flags(req),
363 NULL, NULL);
364 skcipher_request_set_crypt(&subreq, req->src, req->dst,
365 req->cryptlen - tail, req->iv);
366 req = &subreq;
367 }
368
369 err = skcipher_walk_virt(&walk, req, true);
370 if (err)
371 return err;
372
373 crypto_cipher_encrypt_one(ctx->tweak_tfm, walk.iv, walk.iv);
374
375 while (walk.nbytes >= AES_BLOCK_SIZE) {
376 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
377 int reorder_last_tweak = !encrypt && tail > 0;
378
379 if (walk.nbytes < walk.total) {
380 blocks = round_down(blocks,
381 walk.stride / AES_BLOCK_SIZE);
382 reorder_last_tweak = 0;
383 }
384
385 kernel_neon_begin();
386 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
387 ctx->key.rounds, blocks, walk.iv, reorder_last_tweak);
388 kernel_neon_end();
389 err = skcipher_walk_done(&walk,
390 walk.nbytes - blocks * AES_BLOCK_SIZE);
391 }
392
393 if (err || likely(!tail))
394 return err;
395
396 /* handle ciphertext stealing */
397 scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
398 AES_BLOCK_SIZE, 0);
399 memcpy(buf + AES_BLOCK_SIZE, buf, tail);
400 scatterwalk_map_and_copy(buf, req->src, req->cryptlen, tail, 0);
401
402 crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
403
404 if (encrypt)
405 crypto_cipher_encrypt_one(ctx->cts_tfm, buf, buf);
406 else
407 crypto_cipher_decrypt_one(ctx->cts_tfm, buf, buf);
408
409 crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
410
411 scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
412 AES_BLOCK_SIZE + tail, 1);
413 return 0;
414 }
415
xts_encrypt(struct skcipher_request * req)416 static int xts_encrypt(struct skcipher_request *req)
417 {
418 return __xts_crypt(req, true, aesbs_xts_encrypt);
419 }
420
xts_decrypt(struct skcipher_request * req)421 static int xts_decrypt(struct skcipher_request *req)
422 {
423 return __xts_crypt(req, false, aesbs_xts_decrypt);
424 }
425
426 static struct skcipher_alg aes_algs[] = { {
427 .base.cra_name = "__ecb(aes)",
428 .base.cra_driver_name = "__ecb-aes-neonbs",
429 .base.cra_priority = 250,
430 .base.cra_blocksize = AES_BLOCK_SIZE,
431 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
432 .base.cra_module = THIS_MODULE,
433 .base.cra_flags = CRYPTO_ALG_INTERNAL,
434
435 .min_keysize = AES_MIN_KEY_SIZE,
436 .max_keysize = AES_MAX_KEY_SIZE,
437 .walksize = 8 * AES_BLOCK_SIZE,
438 .setkey = aesbs_setkey,
439 .encrypt = ecb_encrypt,
440 .decrypt = ecb_decrypt,
441 }, {
442 .base.cra_name = "__cbc(aes)",
443 .base.cra_driver_name = "__cbc-aes-neonbs",
444 .base.cra_priority = 250,
445 .base.cra_blocksize = AES_BLOCK_SIZE,
446 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctx),
447 .base.cra_module = THIS_MODULE,
448 .base.cra_flags = CRYPTO_ALG_INTERNAL |
449 CRYPTO_ALG_NEED_FALLBACK,
450
451 .min_keysize = AES_MIN_KEY_SIZE,
452 .max_keysize = AES_MAX_KEY_SIZE,
453 .walksize = 8 * AES_BLOCK_SIZE,
454 .ivsize = AES_BLOCK_SIZE,
455 .setkey = aesbs_cbc_setkey,
456 .encrypt = cbc_encrypt,
457 .decrypt = cbc_decrypt,
458 .init = cbc_init,
459 .exit = cbc_exit,
460 }, {
461 .base.cra_name = "__ctr(aes)",
462 .base.cra_driver_name = "__ctr-aes-neonbs",
463 .base.cra_priority = 250,
464 .base.cra_blocksize = 1,
465 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
466 .base.cra_module = THIS_MODULE,
467 .base.cra_flags = CRYPTO_ALG_INTERNAL,
468
469 .min_keysize = AES_MIN_KEY_SIZE,
470 .max_keysize = AES_MAX_KEY_SIZE,
471 .chunksize = AES_BLOCK_SIZE,
472 .walksize = 8 * AES_BLOCK_SIZE,
473 .ivsize = AES_BLOCK_SIZE,
474 .setkey = aesbs_setkey,
475 .encrypt = ctr_encrypt,
476 .decrypt = ctr_encrypt,
477 }, {
478 .base.cra_name = "ctr(aes)",
479 .base.cra_driver_name = "ctr-aes-neonbs-sync",
480 .base.cra_priority = 250 - 1,
481 .base.cra_blocksize = 1,
482 .base.cra_ctxsize = sizeof(struct aesbs_ctr_ctx),
483 .base.cra_module = THIS_MODULE,
484
485 .min_keysize = AES_MIN_KEY_SIZE,
486 .max_keysize = AES_MAX_KEY_SIZE,
487 .chunksize = AES_BLOCK_SIZE,
488 .walksize = 8 * AES_BLOCK_SIZE,
489 .ivsize = AES_BLOCK_SIZE,
490 .setkey = aesbs_ctr_setkey_sync,
491 .encrypt = ctr_encrypt_sync,
492 .decrypt = ctr_encrypt_sync,
493 }, {
494 .base.cra_name = "__xts(aes)",
495 .base.cra_driver_name = "__xts-aes-neonbs",
496 .base.cra_priority = 250,
497 .base.cra_blocksize = AES_BLOCK_SIZE,
498 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
499 .base.cra_module = THIS_MODULE,
500 .base.cra_flags = CRYPTO_ALG_INTERNAL,
501
502 .min_keysize = 2 * AES_MIN_KEY_SIZE,
503 .max_keysize = 2 * AES_MAX_KEY_SIZE,
504 .walksize = 8 * AES_BLOCK_SIZE,
505 .ivsize = AES_BLOCK_SIZE,
506 .setkey = aesbs_xts_setkey,
507 .encrypt = xts_encrypt,
508 .decrypt = xts_decrypt,
509 .init = xts_init,
510 .exit = xts_exit,
511 } };
512
513 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
514
aes_exit(void)515 static void aes_exit(void)
516 {
517 int i;
518
519 for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
520 if (aes_simd_algs[i])
521 simd_skcipher_free(aes_simd_algs[i]);
522
523 crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
524 }
525
aes_init(void)526 static int __init aes_init(void)
527 {
528 struct simd_skcipher_alg *simd;
529 const char *basename;
530 const char *algname;
531 const char *drvname;
532 int err;
533 int i;
534
535 if (!(elf_hwcap & HWCAP_NEON))
536 return -ENODEV;
537
538 err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
539 if (err)
540 return err;
541
542 for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
543 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
544 continue;
545
546 algname = aes_algs[i].base.cra_name + 2;
547 drvname = aes_algs[i].base.cra_driver_name + 2;
548 basename = aes_algs[i].base.cra_driver_name;
549 simd = simd_skcipher_create_compat(algname, drvname, basename);
550 err = PTR_ERR(simd);
551 if (IS_ERR(simd))
552 goto unregister_simds;
553
554 aes_simd_algs[i] = simd;
555 }
556 return 0;
557
558 unregister_simds:
559 aes_exit();
560 return err;
561 }
562
563 late_initcall(aes_init);
564 module_exit(aes_exit);
565
