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