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