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[]);
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 const u8 *src = walk.src.virt.addr;
247 u8 *dst = walk.dst.virt.addr;
248 int bytes = walk.nbytes;
249
250 if (unlikely(bytes < AES_BLOCK_SIZE))
251 src = dst = memcpy(buf + sizeof(buf) - bytes,
252 src, bytes);
253 else if (walk.nbytes < walk.total)
254 bytes &= ~(8 * AES_BLOCK_SIZE - 1);
255
256 kernel_neon_begin();
257 aesbs_ctr_encrypt(dst, src, ctx->rk, ctx->rounds, bytes, walk.iv);
258 kernel_neon_end();
259
260 if (unlikely(bytes < AES_BLOCK_SIZE))
261 memcpy(walk.dst.virt.addr,
262 buf + sizeof(buf) - bytes, bytes);
263
264 err = skcipher_walk_done(&walk, walk.nbytes - bytes);
265 }
266
267 return err;
268 }
269
ctr_encrypt_one(struct crypto_skcipher * tfm,const u8 * src,u8 * dst)270 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
271 {
272 struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
273 unsigned long flags;
274
275 /*
276 * Temporarily disable interrupts to avoid races where
277 * cachelines are evicted when the CPU is interrupted
278 * to do something else.
279 */
280 local_irq_save(flags);
281 aes_encrypt(&ctx->fallback, dst, src);
282 local_irq_restore(flags);
283 }
284
ctr_encrypt_sync(struct skcipher_request * req)285 static int ctr_encrypt_sync(struct skcipher_request *req)
286 {
287 if (!crypto_simd_usable())
288 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
289
290 return ctr_encrypt(req);
291 }
292
aesbs_xts_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)293 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
294 unsigned int key_len)
295 {
296 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
297 int err;
298
299 err = xts_verify_key(tfm, in_key, key_len);
300 if (err)
301 return err;
302
303 key_len /= 2;
304 err = crypto_cipher_setkey(ctx->cts_tfm, in_key, key_len);
305 if (err)
306 return err;
307 err = crypto_cipher_setkey(ctx->tweak_tfm, in_key + key_len, key_len);
308 if (err)
309 return err;
310
311 return aesbs_setkey(tfm, in_key, key_len);
312 }
313
xts_init(struct crypto_skcipher * tfm)314 static int xts_init(struct crypto_skcipher *tfm)
315 {
316 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
317
318 ctx->cts_tfm = crypto_alloc_cipher("aes", 0, 0);
319 if (IS_ERR(ctx->cts_tfm))
320 return PTR_ERR(ctx->cts_tfm);
321
322 ctx->tweak_tfm = crypto_alloc_cipher("aes", 0, 0);
323 if (IS_ERR(ctx->tweak_tfm))
324 crypto_free_cipher(ctx->cts_tfm);
325
326 return PTR_ERR_OR_ZERO(ctx->tweak_tfm);
327 }
328
xts_exit(struct crypto_skcipher * tfm)329 static void xts_exit(struct crypto_skcipher *tfm)
330 {
331 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
332
333 crypto_free_cipher(ctx->tweak_tfm);
334 crypto_free_cipher(ctx->cts_tfm);
335 }
336
__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))337 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
338 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
339 int rounds, int blocks, u8 iv[], int))
340 {
341 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
342 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
343 int tail = req->cryptlen % AES_BLOCK_SIZE;
344 struct skcipher_request subreq;
345 u8 buf[2 * AES_BLOCK_SIZE];
346 struct skcipher_walk walk;
347 int err;
348
349 if (req->cryptlen < AES_BLOCK_SIZE)
350 return -EINVAL;
351
352 if (unlikely(tail)) {
353 skcipher_request_set_tfm(&subreq, tfm);
354 skcipher_request_set_callback(&subreq,
355 skcipher_request_flags(req),
356 NULL, NULL);
357 skcipher_request_set_crypt(&subreq, req->src, req->dst,
358 req->cryptlen - tail, req->iv);
359 req = &subreq;
360 }
361
362 err = skcipher_walk_virt(&walk, req, true);
363 if (err)
364 return err;
365
366 crypto_cipher_encrypt_one(ctx->tweak_tfm, walk.iv, walk.iv);
367
368 while (walk.nbytes >= AES_BLOCK_SIZE) {
369 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
370 int reorder_last_tweak = !encrypt && tail > 0;
371
372 if (walk.nbytes < walk.total) {
373 blocks = round_down(blocks,
374 walk.stride / AES_BLOCK_SIZE);
375 reorder_last_tweak = 0;
376 }
377
378 kernel_neon_begin();
379 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
380 ctx->key.rounds, blocks, walk.iv, reorder_last_tweak);
381 kernel_neon_end();
382 err = skcipher_walk_done(&walk,
383 walk.nbytes - blocks * AES_BLOCK_SIZE);
384 }
385
386 if (err || likely(!tail))
387 return err;
388
389 /* handle ciphertext stealing */
390 scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
391 AES_BLOCK_SIZE, 0);
392 memcpy(buf + AES_BLOCK_SIZE, buf, tail);
393 scatterwalk_map_and_copy(buf, req->src, req->cryptlen, tail, 0);
394
395 crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
396
397 if (encrypt)
398 crypto_cipher_encrypt_one(ctx->cts_tfm, buf, buf);
399 else
400 crypto_cipher_decrypt_one(ctx->cts_tfm, buf, buf);
401
402 crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
403
404 scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
405 AES_BLOCK_SIZE + tail, 1);
406 return 0;
407 }
408
xts_encrypt(struct skcipher_request * req)409 static int xts_encrypt(struct skcipher_request *req)
410 {
411 return __xts_crypt(req, true, aesbs_xts_encrypt);
412 }
413
xts_decrypt(struct skcipher_request * req)414 static int xts_decrypt(struct skcipher_request *req)
415 {
416 return __xts_crypt(req, false, aesbs_xts_decrypt);
417 }
418
419 static struct skcipher_alg aes_algs[] = { {
420 .base.cra_name = "__ecb(aes)",
421 .base.cra_driver_name = "__ecb-aes-neonbs",
422 .base.cra_priority = 250,
423 .base.cra_blocksize = AES_BLOCK_SIZE,
424 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
425 .base.cra_module = THIS_MODULE,
426 .base.cra_flags = CRYPTO_ALG_INTERNAL,
427
428 .min_keysize = AES_MIN_KEY_SIZE,
429 .max_keysize = AES_MAX_KEY_SIZE,
430 .walksize = 8 * AES_BLOCK_SIZE,
431 .setkey = aesbs_setkey,
432 .encrypt = ecb_encrypt,
433 .decrypt = ecb_decrypt,
434 }, {
435 .base.cra_name = "__cbc(aes)",
436 .base.cra_driver_name = "__cbc-aes-neonbs",
437 .base.cra_priority = 250,
438 .base.cra_blocksize = AES_BLOCK_SIZE,
439 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctx),
440 .base.cra_module = THIS_MODULE,
441 .base.cra_flags = CRYPTO_ALG_INTERNAL |
442 CRYPTO_ALG_NEED_FALLBACK,
443
444 .min_keysize = AES_MIN_KEY_SIZE,
445 .max_keysize = AES_MAX_KEY_SIZE,
446 .walksize = 8 * AES_BLOCK_SIZE,
447 .ivsize = AES_BLOCK_SIZE,
448 .setkey = aesbs_cbc_setkey,
449 .encrypt = cbc_encrypt,
450 .decrypt = cbc_decrypt,
451 .init = cbc_init,
452 .exit = cbc_exit,
453 }, {
454 .base.cra_name = "__ctr(aes)",
455 .base.cra_driver_name = "__ctr-aes-neonbs",
456 .base.cra_priority = 250,
457 .base.cra_blocksize = 1,
458 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
459 .base.cra_module = THIS_MODULE,
460 .base.cra_flags = CRYPTO_ALG_INTERNAL,
461
462 .min_keysize = AES_MIN_KEY_SIZE,
463 .max_keysize = AES_MAX_KEY_SIZE,
464 .chunksize = AES_BLOCK_SIZE,
465 .walksize = 8 * AES_BLOCK_SIZE,
466 .ivsize = AES_BLOCK_SIZE,
467 .setkey = aesbs_setkey,
468 .encrypt = ctr_encrypt,
469 .decrypt = ctr_encrypt,
470 }, {
471 .base.cra_name = "ctr(aes)",
472 .base.cra_driver_name = "ctr-aes-neonbs-sync",
473 .base.cra_priority = 250 - 1,
474 .base.cra_blocksize = 1,
475 .base.cra_ctxsize = sizeof(struct aesbs_ctr_ctx),
476 .base.cra_module = THIS_MODULE,
477
478 .min_keysize = AES_MIN_KEY_SIZE,
479 .max_keysize = AES_MAX_KEY_SIZE,
480 .chunksize = AES_BLOCK_SIZE,
481 .walksize = 8 * AES_BLOCK_SIZE,
482 .ivsize = AES_BLOCK_SIZE,
483 .setkey = aesbs_ctr_setkey_sync,
484 .encrypt = ctr_encrypt_sync,
485 .decrypt = ctr_encrypt_sync,
486 }, {
487 .base.cra_name = "__xts(aes)",
488 .base.cra_driver_name = "__xts-aes-neonbs",
489 .base.cra_priority = 250,
490 .base.cra_blocksize = AES_BLOCK_SIZE,
491 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
492 .base.cra_module = THIS_MODULE,
493 .base.cra_flags = CRYPTO_ALG_INTERNAL,
494
495 .min_keysize = 2 * AES_MIN_KEY_SIZE,
496 .max_keysize = 2 * AES_MAX_KEY_SIZE,
497 .walksize = 8 * AES_BLOCK_SIZE,
498 .ivsize = AES_BLOCK_SIZE,
499 .setkey = aesbs_xts_setkey,
500 .encrypt = xts_encrypt,
501 .decrypt = xts_decrypt,
502 .init = xts_init,
503 .exit = xts_exit,
504 } };
505
506 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
507
aes_exit(void)508 static void aes_exit(void)
509 {
510 int i;
511
512 for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
513 if (aes_simd_algs[i])
514 simd_skcipher_free(aes_simd_algs[i]);
515
516 crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
517 }
518
aes_init(void)519 static int __init aes_init(void)
520 {
521 struct simd_skcipher_alg *simd;
522 const char *basename;
523 const char *algname;
524 const char *drvname;
525 int err;
526 int i;
527
528 if (!(elf_hwcap & HWCAP_NEON))
529 return -ENODEV;
530
531 err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
532 if (err)
533 return err;
534
535 for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
536 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
537 continue;
538
539 algname = aes_algs[i].base.cra_name + 2;
540 drvname = aes_algs[i].base.cra_driver_name + 2;
541 basename = aes_algs[i].base.cra_driver_name;
542 simd = simd_skcipher_create_compat(aes_algs + i, algname, drvname, basename);
543 err = PTR_ERR(simd);
544 if (IS_ERR(simd))
545 goto unregister_simds;
546
547 aes_simd_algs[i] = simd;
548 }
549 return 0;
550
551 unregister_simds:
552 aes_exit();
553 return err;
554 }
555
556 late_initcall(aes_init);
557 module_exit(aes_exit);
558