1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Bit sliced AES using NEON instructions 4 * 5 * Copyright (C) 2016 - 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 iv[], u8 final[]); 38 39 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[], 40 int rounds, int blocks, u8 iv[]); 41 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[], 42 int rounds, int blocks, u8 iv[]); 43 44 /* borrowed from aes-neon-blk.ko */ 45 asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[], 46 int rounds, int blocks); 47 asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[], 48 int rounds, int blocks, u8 iv[]); 49 asmlinkage void neon_aes_xts_encrypt(u8 out[], u8 const in[], 50 u32 const rk1[], int rounds, int bytes, 51 u32 const rk2[], u8 iv[], int first); 52 asmlinkage void neon_aes_xts_decrypt(u8 out[], u8 const in[], 53 u32 const rk1[], int rounds, int bytes, 54 u32 const rk2[], u8 iv[], int first); 55 56 struct aesbs_ctx { 57 u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32]; 58 int rounds; 59 } __aligned(AES_BLOCK_SIZE); 60 61 struct aesbs_cbc_ctx { 62 struct aesbs_ctx key; 63 u32 enc[AES_MAX_KEYLENGTH_U32]; 64 }; 65 66 struct aesbs_ctr_ctx { 67 struct aesbs_ctx key; /* must be first member */ 68 struct crypto_aes_ctx fallback; 69 }; 70 71 struct aesbs_xts_ctx { 72 struct aesbs_ctx key; 73 u32 twkey[AES_MAX_KEYLENGTH_U32]; 74 struct crypto_aes_ctx cts; 75 }; 76 77 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 78 unsigned int key_len) 79 { 80 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm); 81 struct crypto_aes_ctx rk; 82 int err; 83 84 err = aes_expandkey(&rk, in_key, key_len); 85 if (err) 86 return err; 87 88 ctx->rounds = 6 + key_len / 4; 89 90 kernel_neon_begin(); 91 aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds); 92 kernel_neon_end(); 93 94 return 0; 95 } 96 97 static int __ecb_crypt(struct skcipher_request *req, 98 void (*fn)(u8 out[], u8 const in[], u8 const rk[], 99 int rounds, int blocks)) 100 { 101 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 102 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm); 103 struct skcipher_walk walk; 104 int err; 105 106 err = skcipher_walk_virt(&walk, req, false); 107 108 while (walk.nbytes >= AES_BLOCK_SIZE) { 109 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 110 111 if (walk.nbytes < walk.total) 112 blocks = round_down(blocks, 113 walk.stride / AES_BLOCK_SIZE); 114 115 kernel_neon_begin(); 116 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk, 117 ctx->rounds, blocks); 118 kernel_neon_end(); 119 err = skcipher_walk_done(&walk, 120 walk.nbytes - blocks * AES_BLOCK_SIZE); 121 } 122 123 return err; 124 } 125 126 static int ecb_encrypt(struct skcipher_request *req) 127 { 128 return __ecb_crypt(req, aesbs_ecb_encrypt); 129 } 130 131 static int ecb_decrypt(struct skcipher_request *req) 132 { 133 return __ecb_crypt(req, aesbs_ecb_decrypt); 134 } 135 136 static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 137 unsigned int key_len) 138 { 139 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); 140 struct crypto_aes_ctx rk; 141 int err; 142 143 err = aes_expandkey(&rk, in_key, key_len); 144 if (err) 145 return err; 146 147 ctx->key.rounds = 6 + key_len / 4; 148 149 memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc)); 150 151 kernel_neon_begin(); 152 aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds); 153 kernel_neon_end(); 154 155 return 0; 156 } 157 158 static int cbc_encrypt(struct skcipher_request *req) 159 { 160 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 161 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); 162 struct skcipher_walk walk; 163 int err; 164 165 err = skcipher_walk_virt(&walk, req, false); 166 167 while (walk.nbytes >= AES_BLOCK_SIZE) { 168 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 169 170 /* fall back to the non-bitsliced NEON implementation */ 171 kernel_neon_begin(); 172 neon_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr, 173 ctx->enc, ctx->key.rounds, blocks, 174 walk.iv); 175 kernel_neon_end(); 176 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE); 177 } 178 return err; 179 } 180 181 static int cbc_decrypt(struct skcipher_request *req) 182 { 183 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 184 struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); 185 struct skcipher_walk walk; 186 int err; 187 188 err = skcipher_walk_virt(&walk, req, false); 189 190 while (walk.nbytes >= AES_BLOCK_SIZE) { 191 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 192 193 if (walk.nbytes < walk.total) 194 blocks = round_down(blocks, 195 walk.stride / AES_BLOCK_SIZE); 196 197 kernel_neon_begin(); 198 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr, 199 ctx->key.rk, ctx->key.rounds, blocks, 200 walk.iv); 201 kernel_neon_end(); 202 err = skcipher_walk_done(&walk, 203 walk.nbytes - blocks * AES_BLOCK_SIZE); 204 } 205 206 return err; 207 } 208 209 static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key, 210 unsigned int key_len) 211 { 212 struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm); 213 int err; 214 215 err = aes_expandkey(&ctx->fallback, in_key, key_len); 216 if (err) 217 return err; 218 219 ctx->key.rounds = 6 + key_len / 4; 220 221 kernel_neon_begin(); 222 aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds); 223 kernel_neon_end(); 224 225 return 0; 226 } 227 228 static int ctr_encrypt(struct skcipher_request *req) 229 { 230 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 231 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm); 232 struct skcipher_walk walk; 233 u8 buf[AES_BLOCK_SIZE]; 234 int err; 235 236 err = skcipher_walk_virt(&walk, req, false); 237 238 while (walk.nbytes > 0) { 239 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 240 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL; 241 242 if (walk.nbytes < walk.total) { 243 blocks = round_down(blocks, 244 walk.stride / AES_BLOCK_SIZE); 245 final = NULL; 246 } 247 248 kernel_neon_begin(); 249 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr, 250 ctx->rk, ctx->rounds, blocks, walk.iv, final); 251 kernel_neon_end(); 252 253 if (final) { 254 u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE; 255 u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE; 256 257 crypto_xor_cpy(dst, src, final, 258 walk.total % AES_BLOCK_SIZE); 259 260 err = skcipher_walk_done(&walk, 0); 261 break; 262 } 263 err = skcipher_walk_done(&walk, 264 walk.nbytes - blocks * AES_BLOCK_SIZE); 265 } 266 return err; 267 } 268 269 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 270 unsigned int key_len) 271 { 272 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 273 struct crypto_aes_ctx rk; 274 int err; 275 276 err = xts_verify_key(tfm, in_key, key_len); 277 if (err) 278 return err; 279 280 key_len /= 2; 281 err = aes_expandkey(&ctx->cts, in_key, key_len); 282 if (err) 283 return err; 284 285 err = aes_expandkey(&rk, in_key + key_len, key_len); 286 if (err) 287 return err; 288 289 memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey)); 290 291 return aesbs_setkey(tfm, in_key, key_len); 292 } 293 294 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst) 295 { 296 struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm); 297 unsigned long flags; 298 299 /* 300 * Temporarily disable interrupts to avoid races where 301 * cachelines are evicted when the CPU is interrupted 302 * to do something else. 303 */ 304 local_irq_save(flags); 305 aes_encrypt(&ctx->fallback, dst, src); 306 local_irq_restore(flags); 307 } 308 309 static int ctr_encrypt_sync(struct skcipher_request *req) 310 { 311 if (!crypto_simd_usable()) 312 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one); 313 314 return ctr_encrypt(req); 315 } 316 317 static int __xts_crypt(struct skcipher_request *req, bool encrypt, 318 void (*fn)(u8 out[], u8 const in[], u8 const rk[], 319 int rounds, int blocks, u8 iv[])) 320 { 321 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 322 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 323 int tail = req->cryptlen % (8 * AES_BLOCK_SIZE); 324 struct scatterlist sg_src[2], sg_dst[2]; 325 struct skcipher_request subreq; 326 struct scatterlist *src, *dst; 327 struct skcipher_walk walk; 328 int nbytes, err; 329 int first = 1; 330 u8 *out, *in; 331 332 if (req->cryptlen < AES_BLOCK_SIZE) 333 return -EINVAL; 334 335 /* ensure that the cts tail is covered by a single step */ 336 if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) { 337 int xts_blocks = DIV_ROUND_UP(req->cryptlen, 338 AES_BLOCK_SIZE) - 2; 339 340 skcipher_request_set_tfm(&subreq, tfm); 341 skcipher_request_set_callback(&subreq, 342 skcipher_request_flags(req), 343 NULL, NULL); 344 skcipher_request_set_crypt(&subreq, req->src, req->dst, 345 xts_blocks * AES_BLOCK_SIZE, 346 req->iv); 347 req = &subreq; 348 } else { 349 tail = 0; 350 } 351 352 err = skcipher_walk_virt(&walk, req, false); 353 if (err) 354 return err; 355 356 while (walk.nbytes >= AES_BLOCK_SIZE) { 357 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 358 359 if (walk.nbytes < walk.total || walk.nbytes % AES_BLOCK_SIZE) 360 blocks = round_down(blocks, 361 walk.stride / AES_BLOCK_SIZE); 362 363 out = walk.dst.virt.addr; 364 in = walk.src.virt.addr; 365 nbytes = walk.nbytes; 366 367 kernel_neon_begin(); 368 if (likely(blocks > 6)) { /* plain NEON is faster otherwise */ 369 if (first) 370 neon_aes_ecb_encrypt(walk.iv, walk.iv, 371 ctx->twkey, 372 ctx->key.rounds, 1); 373 first = 0; 374 375 fn(out, in, ctx->key.rk, ctx->key.rounds, blocks, 376 walk.iv); 377 378 out += blocks * AES_BLOCK_SIZE; 379 in += blocks * AES_BLOCK_SIZE; 380 nbytes -= blocks * AES_BLOCK_SIZE; 381 } 382 383 if (walk.nbytes == walk.total && nbytes > 0) 384 goto xts_tail; 385 386 kernel_neon_end(); 387 err = skcipher_walk_done(&walk, nbytes); 388 } 389 390 if (err || likely(!tail)) 391 return err; 392 393 /* handle ciphertext stealing */ 394 dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen); 395 if (req->dst != req->src) 396 dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen); 397 398 skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail, 399 req->iv); 400 401 err = skcipher_walk_virt(&walk, req, false); 402 if (err) 403 return err; 404 405 out = walk.dst.virt.addr; 406 in = walk.src.virt.addr; 407 nbytes = walk.nbytes; 408 409 kernel_neon_begin(); 410 xts_tail: 411 if (encrypt) 412 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, ctx->key.rounds, 413 nbytes, ctx->twkey, walk.iv, first ?: 2); 414 else 415 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, ctx->key.rounds, 416 nbytes, ctx->twkey, walk.iv, first ?: 2); 417 kernel_neon_end(); 418 419 return skcipher_walk_done(&walk, 0); 420 } 421 422 static int xts_encrypt(struct skcipher_request *req) 423 { 424 return __xts_crypt(req, true, aesbs_xts_encrypt); 425 } 426 427 static int xts_decrypt(struct skcipher_request *req) 428 { 429 return __xts_crypt(req, false, aesbs_xts_decrypt); 430 } 431 432 static struct skcipher_alg aes_algs[] = { { 433 .base.cra_name = "__ecb(aes)", 434 .base.cra_driver_name = "__ecb-aes-neonbs", 435 .base.cra_priority = 250, 436 .base.cra_blocksize = AES_BLOCK_SIZE, 437 .base.cra_ctxsize = sizeof(struct aesbs_ctx), 438 .base.cra_module = THIS_MODULE, 439 .base.cra_flags = CRYPTO_ALG_INTERNAL, 440 441 .min_keysize = AES_MIN_KEY_SIZE, 442 .max_keysize = AES_MAX_KEY_SIZE, 443 .walksize = 8 * AES_BLOCK_SIZE, 444 .setkey = aesbs_setkey, 445 .encrypt = ecb_encrypt, 446 .decrypt = ecb_decrypt, 447 }, { 448 .base.cra_name = "__cbc(aes)", 449 .base.cra_driver_name = "__cbc-aes-neonbs", 450 .base.cra_priority = 250, 451 .base.cra_blocksize = AES_BLOCK_SIZE, 452 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctx), 453 .base.cra_module = THIS_MODULE, 454 .base.cra_flags = CRYPTO_ALG_INTERNAL, 455 456 .min_keysize = AES_MIN_KEY_SIZE, 457 .max_keysize = AES_MAX_KEY_SIZE, 458 .walksize = 8 * AES_BLOCK_SIZE, 459 .ivsize = AES_BLOCK_SIZE, 460 .setkey = aesbs_cbc_setkey, 461 .encrypt = cbc_encrypt, 462 .decrypt = cbc_decrypt, 463 }, { 464 .base.cra_name = "__ctr(aes)", 465 .base.cra_driver_name = "__ctr-aes-neonbs", 466 .base.cra_priority = 250, 467 .base.cra_blocksize = 1, 468 .base.cra_ctxsize = sizeof(struct aesbs_ctx), 469 .base.cra_module = THIS_MODULE, 470 .base.cra_flags = CRYPTO_ALG_INTERNAL, 471 472 .min_keysize = AES_MIN_KEY_SIZE, 473 .max_keysize = AES_MAX_KEY_SIZE, 474 .chunksize = AES_BLOCK_SIZE, 475 .walksize = 8 * AES_BLOCK_SIZE, 476 .ivsize = AES_BLOCK_SIZE, 477 .setkey = aesbs_setkey, 478 .encrypt = ctr_encrypt, 479 .decrypt = ctr_encrypt, 480 }, { 481 .base.cra_name = "ctr(aes)", 482 .base.cra_driver_name = "ctr-aes-neonbs", 483 .base.cra_priority = 250 - 1, 484 .base.cra_blocksize = 1, 485 .base.cra_ctxsize = sizeof(struct aesbs_ctr_ctx), 486 .base.cra_module = THIS_MODULE, 487 488 .min_keysize = AES_MIN_KEY_SIZE, 489 .max_keysize = AES_MAX_KEY_SIZE, 490 .chunksize = AES_BLOCK_SIZE, 491 .walksize = 8 * AES_BLOCK_SIZE, 492 .ivsize = AES_BLOCK_SIZE, 493 .setkey = aesbs_ctr_setkey_sync, 494 .encrypt = ctr_encrypt_sync, 495 .decrypt = ctr_encrypt_sync, 496 }, { 497 .base.cra_name = "__xts(aes)", 498 .base.cra_driver_name = "__xts-aes-neonbs", 499 .base.cra_priority = 250, 500 .base.cra_blocksize = AES_BLOCK_SIZE, 501 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx), 502 .base.cra_module = THIS_MODULE, 503 .base.cra_flags = CRYPTO_ALG_INTERNAL, 504 505 .min_keysize = 2 * AES_MIN_KEY_SIZE, 506 .max_keysize = 2 * AES_MAX_KEY_SIZE, 507 .walksize = 8 * AES_BLOCK_SIZE, 508 .ivsize = AES_BLOCK_SIZE, 509 .setkey = aesbs_xts_setkey, 510 .encrypt = xts_encrypt, 511 .decrypt = xts_decrypt, 512 } }; 513 514 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)]; 515 516 static void aes_exit(void) 517 { 518 int i; 519 520 for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++) 521 if (aes_simd_algs[i]) 522 simd_skcipher_free(aes_simd_algs[i]); 523 524 crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs)); 525 } 526 527 static int __init aes_init(void) 528 { 529 struct simd_skcipher_alg *simd; 530 const char *basename; 531 const char *algname; 532 const char *drvname; 533 int err; 534 int i; 535 536 if (!cpu_have_named_feature(ASIMD)) 537 return -ENODEV; 538 539 err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs)); 540 if (err) 541 return err; 542 543 for (i = 0; i < ARRAY_SIZE(aes_algs); i++) { 544 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL)) 545 continue; 546 547 algname = aes_algs[i].base.cra_name + 2; 548 drvname = aes_algs[i].base.cra_driver_name + 2; 549 basename = aes_algs[i].base.cra_driver_name; 550 simd = simd_skcipher_create_compat(algname, drvname, basename); 551 err = PTR_ERR(simd); 552 if (IS_ERR(simd)) 553 goto unregister_simds; 554 555 aes_simd_algs[i] = simd; 556 } 557 return 0; 558 559 unregister_simds: 560 aes_exit(); 561 return err; 562 } 563 564 module_init(aes_init); 565 module_exit(aes_exit); 566