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 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 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 } 116 117 static int ecb_encrypt(struct skcipher_request *req) 118 { 119 return __ecb_crypt(req, aesbs_ecb_encrypt); 120 } 121 122 static int ecb_decrypt(struct skcipher_request *req) 123 { 124 return __ecb_crypt(req, aesbs_ecb_decrypt); 125 } 126 127 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 } 147 148 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 } 163 164 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 } 191 192 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 } 208 209 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 } 215 216 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 } 234 235 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 } 269 270 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 } 284 285 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 } 292 293 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 } 313 314 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 } 328 329 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 } 336 337 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 } 408 409 static int xts_encrypt(struct skcipher_request *req) 410 { 411 return __xts_crypt(req, true, aesbs_xts_encrypt); 412 } 413 414 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)]; 507 508 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 } 518 519 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