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_DESCRIPTION("Bit sliced AES using NEON instructions"); 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 iv[]); 39 40 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[], 41 int rounds, int blocks, u8 iv[]); 42 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[], 43 int rounds, int blocks, u8 iv[]); 44 45 /* borrowed from aes-neon-blk.ko */ 46 asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[], 47 int rounds, int blocks); 48 asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[], 49 int rounds, int blocks, u8 iv[]); 50 asmlinkage void neon_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[], 51 int rounds, int bytes, u8 ctr[]); 52 asmlinkage void neon_aes_xts_encrypt(u8 out[], u8 const in[], 53 u32 const rk1[], int rounds, int bytes, 54 u32 const rk2[], u8 iv[], int first); 55 asmlinkage void neon_aes_xts_decrypt(u8 out[], u8 const in[], 56 u32 const rk1[], int rounds, int bytes, 57 u32 const rk2[], u8 iv[], int first); 58 59 struct aesbs_ctx { 60 u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32]; 61 int rounds; 62 } __aligned(AES_BLOCK_SIZE); 63 64 struct aesbs_cbc_ctr_ctx { 65 struct aesbs_ctx key; 66 u32 enc[AES_MAX_KEYLENGTH_U32]; 67 }; 68 69 struct aesbs_xts_ctx { 70 struct aesbs_ctx key; 71 u32 twkey[AES_MAX_KEYLENGTH_U32]; 72 struct crypto_aes_ctx cts; 73 }; 74 75 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 76 unsigned int key_len) 77 { 78 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm); 79 struct crypto_aes_ctx rk; 80 int err; 81 82 err = aes_expandkey(&rk, in_key, key_len); 83 if (err) 84 return err; 85 86 ctx->rounds = 6 + key_len / 4; 87 88 kernel_neon_begin(); 89 aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds); 90 kernel_neon_end(); 91 92 return 0; 93 } 94 95 static int __ecb_crypt(struct skcipher_request *req, 96 void (*fn)(u8 out[], u8 const in[], u8 const rk[], 97 int rounds, int blocks)) 98 { 99 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 100 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm); 101 struct skcipher_walk walk; 102 int err; 103 104 err = skcipher_walk_virt(&walk, req, false); 105 106 while (walk.nbytes >= AES_BLOCK_SIZE) { 107 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 108 109 if (walk.nbytes < walk.total) 110 blocks = round_down(blocks, 111 walk.stride / AES_BLOCK_SIZE); 112 113 kernel_neon_begin(); 114 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk, 115 ctx->rounds, blocks); 116 kernel_neon_end(); 117 err = skcipher_walk_done(&walk, 118 walk.nbytes - blocks * AES_BLOCK_SIZE); 119 } 120 121 return err; 122 } 123 124 static int ecb_encrypt(struct skcipher_request *req) 125 { 126 return __ecb_crypt(req, aesbs_ecb_encrypt); 127 } 128 129 static int ecb_decrypt(struct skcipher_request *req) 130 { 131 return __ecb_crypt(req, aesbs_ecb_decrypt); 132 } 133 134 static int aesbs_cbc_ctr_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 135 unsigned int key_len) 136 { 137 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm); 138 struct crypto_aes_ctx rk; 139 int err; 140 141 err = aes_expandkey(&rk, in_key, key_len); 142 if (err) 143 return err; 144 145 ctx->key.rounds = 6 + key_len / 4; 146 147 memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc)); 148 149 kernel_neon_begin(); 150 aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds); 151 kernel_neon_end(); 152 memzero_explicit(&rk, sizeof(rk)); 153 154 return 0; 155 } 156 157 static int cbc_encrypt(struct skcipher_request *req) 158 { 159 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 160 struct aesbs_cbc_ctr_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 /* fall back to the non-bitsliced NEON implementation */ 170 kernel_neon_begin(); 171 neon_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr, 172 ctx->enc, ctx->key.rounds, blocks, 173 walk.iv); 174 kernel_neon_end(); 175 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE); 176 } 177 return err; 178 } 179 180 static int cbc_decrypt(struct skcipher_request *req) 181 { 182 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 183 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm); 184 struct skcipher_walk walk; 185 int err; 186 187 err = skcipher_walk_virt(&walk, req, false); 188 189 while (walk.nbytes >= AES_BLOCK_SIZE) { 190 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE; 191 192 if (walk.nbytes < walk.total) 193 blocks = round_down(blocks, 194 walk.stride / AES_BLOCK_SIZE); 195 196 kernel_neon_begin(); 197 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr, 198 ctx->key.rk, ctx->key.rounds, blocks, 199 walk.iv); 200 kernel_neon_end(); 201 err = skcipher_walk_done(&walk, 202 walk.nbytes - blocks * AES_BLOCK_SIZE); 203 } 204 205 return err; 206 } 207 208 static int ctr_encrypt(struct skcipher_request *req) 209 { 210 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 211 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm); 212 struct skcipher_walk walk; 213 int err; 214 215 err = skcipher_walk_virt(&walk, req, false); 216 217 while (walk.nbytes > 0) { 218 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7; 219 int nbytes = walk.nbytes % (8 * AES_BLOCK_SIZE); 220 const u8 *src = walk.src.virt.addr; 221 u8 *dst = walk.dst.virt.addr; 222 223 kernel_neon_begin(); 224 if (blocks >= 8) { 225 aesbs_ctr_encrypt(dst, src, ctx->key.rk, ctx->key.rounds, 226 blocks, walk.iv); 227 dst += blocks * AES_BLOCK_SIZE; 228 src += blocks * AES_BLOCK_SIZE; 229 } 230 if (nbytes && walk.nbytes == walk.total) { 231 u8 buf[AES_BLOCK_SIZE]; 232 u8 *d = dst; 233 234 if (unlikely(nbytes < AES_BLOCK_SIZE)) 235 src = dst = memcpy(buf + sizeof(buf) - nbytes, 236 src, nbytes); 237 238 neon_aes_ctr_encrypt(dst, src, ctx->enc, ctx->key.rounds, 239 nbytes, walk.iv); 240 241 if (unlikely(nbytes < AES_BLOCK_SIZE)) 242 memcpy(d, dst, nbytes); 243 244 nbytes = 0; 245 } 246 kernel_neon_end(); 247 err = skcipher_walk_done(&walk, nbytes); 248 } 249 return err; 250 } 251 252 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 253 unsigned int key_len) 254 { 255 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 256 struct crypto_aes_ctx rk; 257 int err; 258 259 err = xts_verify_key(tfm, in_key, key_len); 260 if (err) 261 return err; 262 263 key_len /= 2; 264 err = aes_expandkey(&ctx->cts, in_key, key_len); 265 if (err) 266 return err; 267 268 err = aes_expandkey(&rk, in_key + key_len, key_len); 269 if (err) 270 return err; 271 272 memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey)); 273 274 return aesbs_setkey(tfm, in_key, key_len); 275 } 276 277 static int __xts_crypt(struct skcipher_request *req, bool encrypt, 278 void (*fn)(u8 out[], u8 const in[], u8 const rk[], 279 int rounds, int blocks, u8 iv[])) 280 { 281 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 282 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 283 int tail = req->cryptlen % (8 * AES_BLOCK_SIZE); 284 struct scatterlist sg_src[2], sg_dst[2]; 285 struct skcipher_request subreq; 286 struct scatterlist *src, *dst; 287 struct skcipher_walk walk; 288 int nbytes, err; 289 int first = 1; 290 u8 *out, *in; 291 292 if (req->cryptlen < AES_BLOCK_SIZE) 293 return -EINVAL; 294 295 /* ensure that the cts tail is covered by a single step */ 296 if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) { 297 int xts_blocks = DIV_ROUND_UP(req->cryptlen, 298 AES_BLOCK_SIZE) - 2; 299 300 skcipher_request_set_tfm(&subreq, tfm); 301 skcipher_request_set_callback(&subreq, 302 skcipher_request_flags(req), 303 NULL, NULL); 304 skcipher_request_set_crypt(&subreq, req->src, req->dst, 305 xts_blocks * AES_BLOCK_SIZE, 306 req->iv); 307 req = &subreq; 308 } else { 309 tail = 0; 310 } 311 312 err = skcipher_walk_virt(&walk, req, false); 313 if (err) 314 return err; 315 316 while (walk.nbytes >= AES_BLOCK_SIZE) { 317 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7; 318 out = walk.dst.virt.addr; 319 in = walk.src.virt.addr; 320 nbytes = walk.nbytes; 321 322 kernel_neon_begin(); 323 if (blocks >= 8) { 324 if (first == 1) 325 neon_aes_ecb_encrypt(walk.iv, walk.iv, 326 ctx->twkey, 327 ctx->key.rounds, 1); 328 first = 2; 329 330 fn(out, in, ctx->key.rk, ctx->key.rounds, blocks, 331 walk.iv); 332 333 out += blocks * AES_BLOCK_SIZE; 334 in += blocks * AES_BLOCK_SIZE; 335 nbytes -= blocks * AES_BLOCK_SIZE; 336 } 337 if (walk.nbytes == walk.total && nbytes > 0) { 338 if (encrypt) 339 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, 340 ctx->key.rounds, nbytes, 341 ctx->twkey, walk.iv, first); 342 else 343 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, 344 ctx->key.rounds, nbytes, 345 ctx->twkey, walk.iv, first); 346 nbytes = first = 0; 347 } 348 kernel_neon_end(); 349 err = skcipher_walk_done(&walk, nbytes); 350 } 351 352 if (err || likely(!tail)) 353 return err; 354 355 /* handle ciphertext stealing */ 356 dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen); 357 if (req->dst != req->src) 358 dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen); 359 360 skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail, 361 req->iv); 362 363 err = skcipher_walk_virt(&walk, req, false); 364 if (err) 365 return err; 366 367 out = walk.dst.virt.addr; 368 in = walk.src.virt.addr; 369 nbytes = walk.nbytes; 370 371 kernel_neon_begin(); 372 if (encrypt) 373 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, ctx->key.rounds, 374 nbytes, ctx->twkey, walk.iv, first); 375 else 376 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, ctx->key.rounds, 377 nbytes, ctx->twkey, walk.iv, first); 378 kernel_neon_end(); 379 380 return skcipher_walk_done(&walk, 0); 381 } 382 383 static int xts_encrypt(struct skcipher_request *req) 384 { 385 return __xts_crypt(req, true, aesbs_xts_encrypt); 386 } 387 388 static int xts_decrypt(struct skcipher_request *req) 389 { 390 return __xts_crypt(req, false, aesbs_xts_decrypt); 391 } 392 393 static struct skcipher_alg aes_algs[] = { { 394 .base.cra_name = "ecb(aes)", 395 .base.cra_driver_name = "ecb-aes-neonbs", 396 .base.cra_priority = 250, 397 .base.cra_blocksize = AES_BLOCK_SIZE, 398 .base.cra_ctxsize = sizeof(struct aesbs_ctx), 399 .base.cra_module = THIS_MODULE, 400 401 .min_keysize = AES_MIN_KEY_SIZE, 402 .max_keysize = AES_MAX_KEY_SIZE, 403 .walksize = 8 * AES_BLOCK_SIZE, 404 .setkey = aesbs_setkey, 405 .encrypt = ecb_encrypt, 406 .decrypt = ecb_decrypt, 407 }, { 408 .base.cra_name = "cbc(aes)", 409 .base.cra_driver_name = "cbc-aes-neonbs", 410 .base.cra_priority = 250, 411 .base.cra_blocksize = AES_BLOCK_SIZE, 412 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx), 413 .base.cra_module = THIS_MODULE, 414 415 .min_keysize = AES_MIN_KEY_SIZE, 416 .max_keysize = AES_MAX_KEY_SIZE, 417 .walksize = 8 * AES_BLOCK_SIZE, 418 .ivsize = AES_BLOCK_SIZE, 419 .setkey = aesbs_cbc_ctr_setkey, 420 .encrypt = cbc_encrypt, 421 .decrypt = cbc_decrypt, 422 }, { 423 .base.cra_name = "ctr(aes)", 424 .base.cra_driver_name = "ctr-aes-neonbs", 425 .base.cra_priority = 250, 426 .base.cra_blocksize = 1, 427 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx), 428 .base.cra_module = THIS_MODULE, 429 430 .min_keysize = AES_MIN_KEY_SIZE, 431 .max_keysize = AES_MAX_KEY_SIZE, 432 .chunksize = AES_BLOCK_SIZE, 433 .walksize = 8 * AES_BLOCK_SIZE, 434 .ivsize = AES_BLOCK_SIZE, 435 .setkey = aesbs_cbc_ctr_setkey, 436 .encrypt = ctr_encrypt, 437 .decrypt = ctr_encrypt, 438 }, { 439 .base.cra_name = "xts(aes)", 440 .base.cra_driver_name = "xts-aes-neonbs", 441 .base.cra_priority = 250, 442 .base.cra_blocksize = AES_BLOCK_SIZE, 443 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx), 444 .base.cra_module = THIS_MODULE, 445 446 .min_keysize = 2 * AES_MIN_KEY_SIZE, 447 .max_keysize = 2 * AES_MAX_KEY_SIZE, 448 .walksize = 8 * AES_BLOCK_SIZE, 449 .ivsize = AES_BLOCK_SIZE, 450 .setkey = aesbs_xts_setkey, 451 .encrypt = xts_encrypt, 452 .decrypt = xts_decrypt, 453 } }; 454 455 static void aes_exit(void) 456 { 457 crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs)); 458 } 459 460 static int __init aes_init(void) 461 { 462 if (!cpu_have_named_feature(ASIMD)) 463 return -ENODEV; 464 465 return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs)); 466 } 467 468 module_init(aes_init); 469 module_exit(aes_exit); 470