| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * HCTR2 length-preserving encryption mode |
| 4 | * |
| 5 | * Copyright 2021 Google LLC |
| 6 | */ |
| 7 | |
| 8 | |
| 9 | /* |
| 10 | * HCTR2 is a length-preserving encryption mode that is efficient on |
| 11 | * processors with instructions to accelerate AES and carryless |
| 12 | * multiplication, e.g. x86 processors with AES-NI and CLMUL, and ARM |
| 13 | * processors with the ARMv8 crypto extensions. |
| 14 | * |
| 15 | * For more details, see the paper: "Length-preserving encryption with HCTR2" |
| 16 | * (https://eprint.iacr.org/2021/1441.pdf) |
| 17 | */ |
| 18 | |
| 19 | #include <crypto/internal/cipher.h> |
| 20 | #include <crypto/internal/hash.h> |
| 21 | #include <crypto/internal/skcipher.h> |
| 22 | #include <crypto/polyval.h> |
| 23 | #include <crypto/scatterwalk.h> |
| 24 | #include <linux/module.h> |
| 25 | |
| 26 | #define BLOCKCIPHER_BLOCK_SIZE 16 |
| 27 | |
| 28 | /* |
| 29 | * The specification allows variable-length tweaks, but Linux's crypto API |
| 30 | * currently only allows algorithms to support a single length. The "natural" |
| 31 | * tweak length for HCTR2 is 16, since that fits into one POLYVAL block for |
| 32 | * the best performance. But longer tweaks are useful for fscrypt, to avoid |
| 33 | * needing to derive per-file keys. So instead we use two blocks, or 32 bytes. |
| 34 | */ |
| 35 | #define TWEAK_SIZE 32 |
| 36 | |
| 37 | struct hctr2_instance_ctx { |
| 38 | struct crypto_cipher_spawn blockcipher_spawn; |
| 39 | struct crypto_skcipher_spawn xctr_spawn; |
| 40 | struct crypto_shash_spawn polyval_spawn; |
| 41 | }; |
| 42 | |
| 43 | struct hctr2_tfm_ctx { |
| 44 | struct crypto_cipher *blockcipher; |
| 45 | struct crypto_skcipher *xctr; |
| 46 | struct crypto_shash *polyval; |
| 47 | u8 L[BLOCKCIPHER_BLOCK_SIZE]; |
| 48 | int hashed_tweak_offset; |
| 49 | /* |
| 50 | * This struct is allocated with extra space for two exported hash |
| 51 | * states. Since the hash state size is not known at compile-time, we |
| 52 | * can't add these to the struct directly. |
| 53 | * |
| 54 | * hashed_tweaklen_divisible; |
| 55 | * hashed_tweaklen_remainder; |
| 56 | */ |
| 57 | }; |
| 58 | |
| 59 | struct hctr2_request_ctx { |
| 60 | u8 first_block[BLOCKCIPHER_BLOCK_SIZE]; |
| 61 | u8 xctr_iv[BLOCKCIPHER_BLOCK_SIZE]; |
| 62 | struct scatterlist *bulk_part_dst; |
| 63 | struct scatterlist *bulk_part_src; |
| 64 | struct scatterlist sg_src[2]; |
| 65 | struct scatterlist sg_dst[2]; |
| 66 | /* |
| 67 | * Sub-request sizes are unknown at compile-time, so they need to go |
| 68 | * after the members with known sizes. |
| 69 | */ |
| 70 | union { |
| 71 | struct shash_desc hash_desc; |
| 72 | struct skcipher_request xctr_req; |
| 73 | } u; |
| 74 | /* |
| 75 | * This struct is allocated with extra space for one exported hash |
| 76 | * state. Since the hash state size is not known at compile-time, we |
| 77 | * can't add it to the struct directly. |
| 78 | * |
| 79 | * hashed_tweak; |
| 80 | */ |
| 81 | }; |
| 82 | |
| 83 | static inline u8 *hctr2_hashed_tweaklen(const struct hctr2_tfm_ctx *tctx, |
| 84 | bool has_remainder) |
| 85 | { |
| 86 | u8 *p = (u8 *)tctx + sizeof(*tctx); |
| 87 | |
| 88 | if (has_remainder) /* For messages not a multiple of block length */ |
| 89 | p += crypto_shash_statesize(tctx->polyval); |
| 90 | return p; |
| 91 | } |
| 92 | |
| 93 | static inline u8 *hctr2_hashed_tweak(const struct hctr2_tfm_ctx *tctx, |
| 94 | struct hctr2_request_ctx *rctx) |
| 95 | { |
| 96 | return (u8 *)rctx + tctx->hashed_tweak_offset; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * The input data for each HCTR2 hash step begins with a 16-byte block that |
| 101 | * contains the tweak length and a flag that indicates whether the input is evenly |
| 102 | * divisible into blocks. Since this implementation only supports one tweak |
| 103 | * length, we precompute the two hash states resulting from hashing the two |
| 104 | * possible values of this initial block. This reduces by one block the amount of |
| 105 | * data that needs to be hashed for each encryption/decryption |
| 106 | * |
| 107 | * These precomputed hashes are stored in hctr2_tfm_ctx. |
| 108 | */ |
| 109 | static int hctr2_hash_tweaklen(struct hctr2_tfm_ctx *tctx, bool has_remainder) |
| 110 | { |
| 111 | SHASH_DESC_ON_STACK(shash, tfm->polyval); |
| 112 | __le64 tweak_length_block[2]; |
| 113 | int err; |
| 114 | |
| 115 | shash->tfm = tctx->polyval; |
| 116 | memset(tweak_length_block, 0, sizeof(tweak_length_block)); |
| 117 | |
| 118 | tweak_length_block[0] = cpu_to_le64(TWEAK_SIZE * 8 * 2 + 2 + has_remainder); |
| 119 | err = crypto_shash_init(shash); |
| 120 | if (err) |
| 121 | return err; |
| 122 | err = crypto_shash_update(shash, (u8 *)tweak_length_block, |
| 123 | POLYVAL_BLOCK_SIZE); |
| 124 | if (err) |
| 125 | return err; |
| 126 | return crypto_shash_export(shash, hctr2_hashed_tweaklen(tctx, has_remainder)); |
| 127 | } |
| 128 | |
| 129 | static int hctr2_setkey(struct crypto_skcipher *tfm, const u8 *key, |
| 130 | unsigned int keylen) |
| 131 | { |
| 132 | struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); |
| 133 | u8 hbar[BLOCKCIPHER_BLOCK_SIZE]; |
| 134 | int err; |
| 135 | |
| 136 | crypto_cipher_clear_flags(tctx->blockcipher, CRYPTO_TFM_REQ_MASK); |
| 137 | crypto_cipher_set_flags(tctx->blockcipher, |
| 138 | crypto_skcipher_get_flags(tfm) & |
| 139 | CRYPTO_TFM_REQ_MASK); |
| 140 | err = crypto_cipher_setkey(tctx->blockcipher, key, keylen); |
| 141 | if (err) |
| 142 | return err; |
| 143 | |
| 144 | crypto_skcipher_clear_flags(tctx->xctr, CRYPTO_TFM_REQ_MASK); |
| 145 | crypto_skcipher_set_flags(tctx->xctr, |
| 146 | crypto_skcipher_get_flags(tfm) & |
| 147 | CRYPTO_TFM_REQ_MASK); |
| 148 | err = crypto_skcipher_setkey(tctx->xctr, key, keylen); |
| 149 | if (err) |
| 150 | return err; |
| 151 | |
| 152 | memset(hbar, 0, sizeof(hbar)); |
| 153 | crypto_cipher_encrypt_one(tctx->blockcipher, hbar, hbar); |
| 154 | |
| 155 | memset(tctx->L, 0, sizeof(tctx->L)); |
| 156 | tctx->L[0] = 0x01; |
| 157 | crypto_cipher_encrypt_one(tctx->blockcipher, tctx->L, tctx->L); |
| 158 | |
| 159 | crypto_shash_clear_flags(tctx->polyval, CRYPTO_TFM_REQ_MASK); |
| 160 | crypto_shash_set_flags(tctx->polyval, crypto_skcipher_get_flags(tfm) & |
| 161 | CRYPTO_TFM_REQ_MASK); |
| 162 | err = crypto_shash_setkey(tctx->polyval, hbar, BLOCKCIPHER_BLOCK_SIZE); |
| 163 | if (err) |
| 164 | return err; |
| 165 | memzero_explicit(hbar, sizeof(hbar)); |
| 166 | |
| 167 | return hctr2_hash_tweaklen(tctx, true) ?: hctr2_hash_tweaklen(tctx, false); |
| 168 | } |
| 169 | |
| 170 | static int hctr2_hash_tweak(struct skcipher_request *req) |
| 171 | { |
| 172 | struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); |
| 173 | const struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); |
| 174 | struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); |
| 175 | struct shash_desc *hash_desc = &rctx->u.hash_desc; |
| 176 | int err; |
| 177 | bool has_remainder = req->cryptlen % POLYVAL_BLOCK_SIZE; |
| 178 | |
| 179 | hash_desc->tfm = tctx->polyval; |
| 180 | err = crypto_shash_import(hash_desc, hctr2_hashed_tweaklen(tctx, has_remainder)); |
| 181 | if (err) |
| 182 | return err; |
| 183 | err = crypto_shash_update(hash_desc, req->iv, TWEAK_SIZE); |
| 184 | if (err) |
| 185 | return err; |
| 186 | |
| 187 | // Store the hashed tweak, since we need it when computing both |
| 188 | // H(T || N) and H(T || V). |
| 189 | return crypto_shash_export(hash_desc, hctr2_hashed_tweak(tctx, rctx)); |
| 190 | } |
| 191 | |
| 192 | static int hctr2_hash_message(struct skcipher_request *req, |
| 193 | struct scatterlist *sgl, |
| 194 | u8 digest[POLYVAL_DIGEST_SIZE]) |
| 195 | { |
| 196 | static const u8 padding[BLOCKCIPHER_BLOCK_SIZE] = { 0x1 }; |
| 197 | struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); |
| 198 | struct shash_desc *hash_desc = &rctx->u.hash_desc; |
| 199 | const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE; |
| 200 | struct sg_mapping_iter miter; |
| 201 | unsigned int remainder = bulk_len % BLOCKCIPHER_BLOCK_SIZE; |
| 202 | int i; |
| 203 | int err = 0; |
| 204 | int n = 0; |
| 205 | |
| 206 | sg_miter_start(&miter, sgl, sg_nents(sgl), |
| 207 | SG_MITER_FROM_SG | SG_MITER_ATOMIC); |
| 208 | for (i = 0; i < bulk_len; i += n) { |
| 209 | sg_miter_next(&miter); |
| 210 | n = min_t(unsigned int, miter.length, bulk_len - i); |
| 211 | err = crypto_shash_update(hash_desc, miter.addr, n); |
| 212 | if (err) |
| 213 | break; |
| 214 | } |
| 215 | sg_miter_stop(&miter); |
| 216 | |
| 217 | if (err) |
| 218 | return err; |
| 219 | |
| 220 | if (remainder) { |
| 221 | err = crypto_shash_update(hash_desc, padding, |
| 222 | BLOCKCIPHER_BLOCK_SIZE - remainder); |
| 223 | if (err) |
| 224 | return err; |
| 225 | } |
| 226 | return crypto_shash_final(hash_desc, digest); |
| 227 | } |
| 228 | |
| 229 | static int hctr2_finish(struct skcipher_request *req) |
| 230 | { |
| 231 | struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); |
| 232 | const struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); |
| 233 | struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); |
| 234 | u8 digest[POLYVAL_DIGEST_SIZE]; |
| 235 | struct shash_desc *hash_desc = &rctx->u.hash_desc; |
| 236 | int err; |
| 237 | |
| 238 | // U = UU ^ H(T || V) |
| 239 | // or M = MM ^ H(T || N) |
| 240 | hash_desc->tfm = tctx->polyval; |
| 241 | err = crypto_shash_import(hash_desc, hctr2_hashed_tweak(tctx, rctx)); |
| 242 | if (err) |
| 243 | return err; |
| 244 | err = hctr2_hash_message(req, rctx->bulk_part_dst, digest); |
| 245 | if (err) |
| 246 | return err; |
| 247 | crypto_xor(rctx->first_block, digest, BLOCKCIPHER_BLOCK_SIZE); |
| 248 | |
| 249 | // Copy U (or M) into dst scatterlist |
| 250 | scatterwalk_map_and_copy(rctx->first_block, req->dst, |
| 251 | 0, BLOCKCIPHER_BLOCK_SIZE, 1); |
| 252 | return 0; |
| 253 | } |
| 254 | |
| 255 | static void hctr2_xctr_done(void *data, int err) |
| 256 | { |
| 257 | struct skcipher_request *req = data; |
| 258 | |
| 259 | if (!err) |
| 260 | err = hctr2_finish(req); |
| 261 | |
| 262 | skcipher_request_complete(req, err); |
| 263 | } |
| 264 | |
| 265 | static int hctr2_crypt(struct skcipher_request *req, bool enc) |
| 266 | { |
| 267 | struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); |
| 268 | const struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); |
| 269 | struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); |
| 270 | u8 digest[POLYVAL_DIGEST_SIZE]; |
| 271 | int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE; |
| 272 | int err; |
| 273 | |
| 274 | // Requests must be at least one block |
| 275 | if (req->cryptlen < BLOCKCIPHER_BLOCK_SIZE) |
| 276 | return -EINVAL; |
| 277 | |
| 278 | // Copy M (or U) into a temporary buffer |
| 279 | scatterwalk_map_and_copy(rctx->first_block, req->src, |
| 280 | 0, BLOCKCIPHER_BLOCK_SIZE, 0); |
| 281 | |
| 282 | // Create scatterlists for N and V |
| 283 | rctx->bulk_part_src = scatterwalk_ffwd(rctx->sg_src, req->src, |
| 284 | BLOCKCIPHER_BLOCK_SIZE); |
| 285 | rctx->bulk_part_dst = scatterwalk_ffwd(rctx->sg_dst, req->dst, |
| 286 | BLOCKCIPHER_BLOCK_SIZE); |
| 287 | |
| 288 | // MM = M ^ H(T || N) |
| 289 | // or UU = U ^ H(T || V) |
| 290 | err = hctr2_hash_tweak(req); |
| 291 | if (err) |
| 292 | return err; |
| 293 | err = hctr2_hash_message(req, rctx->bulk_part_src, digest); |
| 294 | if (err) |
| 295 | return err; |
| 296 | crypto_xor(digest, rctx->first_block, BLOCKCIPHER_BLOCK_SIZE); |
| 297 | |
| 298 | // UU = E(MM) |
| 299 | // or MM = D(UU) |
| 300 | if (enc) |
| 301 | crypto_cipher_encrypt_one(tctx->blockcipher, rctx->first_block, |
| 302 | digest); |
| 303 | else |
| 304 | crypto_cipher_decrypt_one(tctx->blockcipher, rctx->first_block, |
| 305 | digest); |
| 306 | |
| 307 | // S = MM ^ UU ^ L |
| 308 | crypto_xor(digest, rctx->first_block, BLOCKCIPHER_BLOCK_SIZE); |
| 309 | crypto_xor_cpy(rctx->xctr_iv, digest, tctx->L, BLOCKCIPHER_BLOCK_SIZE); |
| 310 | |
| 311 | // V = XCTR(S, N) |
| 312 | // or N = XCTR(S, V) |
| 313 | skcipher_request_set_tfm(&rctx->u.xctr_req, tctx->xctr); |
| 314 | skcipher_request_set_crypt(&rctx->u.xctr_req, rctx->bulk_part_src, |
| 315 | rctx->bulk_part_dst, bulk_len, |
| 316 | rctx->xctr_iv); |
| 317 | skcipher_request_set_callback(&rctx->u.xctr_req, |
| 318 | req->base.flags, |
| 319 | hctr2_xctr_done, req); |
| 320 | return crypto_skcipher_encrypt(&rctx->u.xctr_req) ?: |
| 321 | hctr2_finish(req); |
| 322 | } |
| 323 | |
| 324 | static int hctr2_encrypt(struct skcipher_request *req) |
| 325 | { |
| 326 | return hctr2_crypt(req, true); |
| 327 | } |
| 328 | |
| 329 | static int hctr2_decrypt(struct skcipher_request *req) |
| 330 | { |
| 331 | return hctr2_crypt(req, false); |
| 332 | } |
| 333 | |
| 334 | static int hctr2_init_tfm(struct crypto_skcipher *tfm) |
| 335 | { |
| 336 | struct skcipher_instance *inst = skcipher_alg_instance(tfm); |
| 337 | struct hctr2_instance_ctx *ictx = skcipher_instance_ctx(inst); |
| 338 | struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); |
| 339 | struct crypto_skcipher *xctr; |
| 340 | struct crypto_cipher *blockcipher; |
| 341 | struct crypto_shash *polyval; |
| 342 | unsigned int subreq_size; |
| 343 | int err; |
| 344 | |
| 345 | xctr = crypto_spawn_skcipher(&ictx->xctr_spawn); |
| 346 | if (IS_ERR(xctr)) |
| 347 | return PTR_ERR(xctr); |
| 348 | |
| 349 | blockcipher = crypto_spawn_cipher(&ictx->blockcipher_spawn); |
| 350 | if (IS_ERR(blockcipher)) { |
| 351 | err = PTR_ERR(blockcipher); |
| 352 | goto err_free_xctr; |
| 353 | } |
| 354 | |
| 355 | polyval = crypto_spawn_shash(&ictx->polyval_spawn); |
| 356 | if (IS_ERR(polyval)) { |
| 357 | err = PTR_ERR(polyval); |
| 358 | goto err_free_blockcipher; |
| 359 | } |
| 360 | |
| 361 | tctx->xctr = xctr; |
| 362 | tctx->blockcipher = blockcipher; |
| 363 | tctx->polyval = polyval; |
| 364 | |
| 365 | BUILD_BUG_ON(offsetofend(struct hctr2_request_ctx, u) != |
| 366 | sizeof(struct hctr2_request_ctx)); |
| 367 | subreq_size = max(sizeof_field(struct hctr2_request_ctx, u.hash_desc) + |
| 368 | crypto_shash_descsize(polyval), |
| 369 | sizeof_field(struct hctr2_request_ctx, u.xctr_req) + |
| 370 | crypto_skcipher_reqsize(xctr)); |
| 371 | |
| 372 | tctx->hashed_tweak_offset = offsetof(struct hctr2_request_ctx, u) + |
| 373 | subreq_size; |
| 374 | crypto_skcipher_set_reqsize(tfm, tctx->hashed_tweak_offset + |
| 375 | crypto_shash_statesize(polyval)); |
| 376 | return 0; |
| 377 | |
| 378 | err_free_blockcipher: |
| 379 | crypto_free_cipher(blockcipher); |
| 380 | err_free_xctr: |
| 381 | crypto_free_skcipher(xctr); |
| 382 | return err; |
| 383 | } |
| 384 | |
| 385 | static void hctr2_exit_tfm(struct crypto_skcipher *tfm) |
| 386 | { |
| 387 | struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); |
| 388 | |
| 389 | crypto_free_cipher(tctx->blockcipher); |
| 390 | crypto_free_skcipher(tctx->xctr); |
| 391 | crypto_free_shash(tctx->polyval); |
| 392 | } |
| 393 | |
| 394 | static void hctr2_free_instance(struct skcipher_instance *inst) |
| 395 | { |
| 396 | struct hctr2_instance_ctx *ictx = skcipher_instance_ctx(inst); |
| 397 | |
| 398 | crypto_drop_cipher(&ictx->blockcipher_spawn); |
| 399 | crypto_drop_skcipher(&ictx->xctr_spawn); |
| 400 | crypto_drop_shash(&ictx->polyval_spawn); |
| 401 | kfree(inst); |
| 402 | } |
| 403 | |
| 404 | static int hctr2_create_common(struct crypto_template *tmpl, |
| 405 | struct rtattr **tb, |
| 406 | const char *xctr_name, |
| 407 | const char *polyval_name) |
| 408 | { |
| 409 | u32 mask; |
| 410 | struct skcipher_instance *inst; |
| 411 | struct hctr2_instance_ctx *ictx; |
| 412 | struct skcipher_alg *xctr_alg; |
| 413 | struct crypto_alg *blockcipher_alg; |
| 414 | struct shash_alg *polyval_alg; |
| 415 | char blockcipher_name[CRYPTO_MAX_ALG_NAME]; |
| 416 | int len; |
| 417 | int err; |
| 418 | |
| 419 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask); |
| 420 | if (err) |
| 421 | return err; |
| 422 | |
| 423 | inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL); |
| 424 | if (!inst) |
| 425 | return -ENOMEM; |
| 426 | ictx = skcipher_instance_ctx(inst); |
| 427 | |
| 428 | /* Stream cipher, xctr(block_cipher) */ |
| 429 | err = crypto_grab_skcipher(&ictx->xctr_spawn, |
| 430 | skcipher_crypto_instance(inst), |
| 431 | xctr_name, 0, mask); |
| 432 | if (err) |
| 433 | goto err_free_inst; |
| 434 | xctr_alg = crypto_spawn_skcipher_alg(&ictx->xctr_spawn); |
| 435 | |
| 436 | err = -EINVAL; |
| 437 | if (strncmp(xctr_alg->base.cra_name, "xctr(", 5)) |
| 438 | goto err_free_inst; |
| 439 | len = strscpy(blockcipher_name, xctr_alg->base.cra_name + 5, |
| 440 | sizeof(blockcipher_name)); |
| 441 | if (len < 1) |
| 442 | goto err_free_inst; |
| 443 | if (blockcipher_name[len - 1] != ')') |
| 444 | goto err_free_inst; |
| 445 | blockcipher_name[len - 1] = 0; |
| 446 | |
| 447 | /* Block cipher, e.g. "aes" */ |
| 448 | err = crypto_grab_cipher(&ictx->blockcipher_spawn, |
| 449 | skcipher_crypto_instance(inst), |
| 450 | blockcipher_name, 0, mask); |
| 451 | if (err) |
| 452 | goto err_free_inst; |
| 453 | blockcipher_alg = crypto_spawn_cipher_alg(&ictx->blockcipher_spawn); |
| 454 | |
| 455 | /* Require blocksize of 16 bytes */ |
| 456 | err = -EINVAL; |
| 457 | if (blockcipher_alg->cra_blocksize != BLOCKCIPHER_BLOCK_SIZE) |
| 458 | goto err_free_inst; |
| 459 | |
| 460 | /* Polyval ε-∆U hash function */ |
| 461 | err = crypto_grab_shash(&ictx->polyval_spawn, |
| 462 | skcipher_crypto_instance(inst), |
| 463 | polyval_name, 0, mask); |
| 464 | if (err) |
| 465 | goto err_free_inst; |
| 466 | polyval_alg = crypto_spawn_shash_alg(&ictx->polyval_spawn); |
| 467 | |
| 468 | /* Ensure Polyval is being used */ |
| 469 | err = -EINVAL; |
| 470 | if (strcmp(polyval_alg->base.cra_name, "polyval") != 0) |
| 471 | goto err_free_inst; |
| 472 | |
| 473 | /* Instance fields */ |
| 474 | |
| 475 | err = -ENAMETOOLONG; |
| 476 | if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, "hctr2(%s)", |
| 477 | blockcipher_alg->cra_name) >= CRYPTO_MAX_ALG_NAME) |
| 478 | goto err_free_inst; |
| 479 | if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, |
| 480 | "hctr2_base(%s,%s)", |
| 481 | xctr_alg->base.cra_driver_name, |
| 482 | polyval_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) |
| 483 | goto err_free_inst; |
| 484 | |
| 485 | inst->alg.base.cra_blocksize = BLOCKCIPHER_BLOCK_SIZE; |
| 486 | inst->alg.base.cra_ctxsize = sizeof(struct hctr2_tfm_ctx) + |
| 487 | polyval_alg->statesize * 2; |
| 488 | inst->alg.base.cra_alignmask = xctr_alg->base.cra_alignmask | |
| 489 | polyval_alg->base.cra_alignmask; |
| 490 | /* |
| 491 | * The hash function is called twice, so it is weighted higher than the |
| 492 | * xctr and blockcipher. |
| 493 | */ |
| 494 | inst->alg.base.cra_priority = (2 * xctr_alg->base.cra_priority + |
| 495 | 4 * polyval_alg->base.cra_priority + |
| 496 | blockcipher_alg->cra_priority) / 7; |
| 497 | |
| 498 | inst->alg.setkey = hctr2_setkey; |
| 499 | inst->alg.encrypt = hctr2_encrypt; |
| 500 | inst->alg.decrypt = hctr2_decrypt; |
| 501 | inst->alg.init = hctr2_init_tfm; |
| 502 | inst->alg.exit = hctr2_exit_tfm; |
| 503 | inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(xctr_alg); |
| 504 | inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(xctr_alg); |
| 505 | inst->alg.ivsize = TWEAK_SIZE; |
| 506 | |
| 507 | inst->free = hctr2_free_instance; |
| 508 | |
| 509 | err = skcipher_register_instance(tmpl, inst); |
| 510 | if (err) { |
| 511 | err_free_inst: |
| 512 | hctr2_free_instance(inst); |
| 513 | } |
| 514 | return err; |
| 515 | } |
| 516 | |
| 517 | static int hctr2_create_base(struct crypto_template *tmpl, struct rtattr **tb) |
| 518 | { |
| 519 | const char *xctr_name; |
| 520 | const char *polyval_name; |
| 521 | |
| 522 | xctr_name = crypto_attr_alg_name(tb[1]); |
| 523 | if (IS_ERR(xctr_name)) |
| 524 | return PTR_ERR(xctr_name); |
| 525 | |
| 526 | polyval_name = crypto_attr_alg_name(tb[2]); |
| 527 | if (IS_ERR(polyval_name)) |
| 528 | return PTR_ERR(polyval_name); |
| 529 | |
| 530 | return hctr2_create_common(tmpl, tb, xctr_name, polyval_name); |
| 531 | } |
| 532 | |
| 533 | static int hctr2_create(struct crypto_template *tmpl, struct rtattr **tb) |
| 534 | { |
| 535 | const char *blockcipher_name; |
| 536 | char xctr_name[CRYPTO_MAX_ALG_NAME]; |
| 537 | |
| 538 | blockcipher_name = crypto_attr_alg_name(tb[1]); |
| 539 | if (IS_ERR(blockcipher_name)) |
| 540 | return PTR_ERR(blockcipher_name); |
| 541 | |
| 542 | if (snprintf(xctr_name, CRYPTO_MAX_ALG_NAME, "xctr(%s)", |
| 543 | blockcipher_name) >= CRYPTO_MAX_ALG_NAME) |
| 544 | return -ENAMETOOLONG; |
| 545 | |
| 546 | return hctr2_create_common(tmpl, tb, xctr_name, "polyval"); |
| 547 | } |
| 548 | |
| 549 | static struct crypto_template hctr2_tmpls[] = { |
| 550 | { |
| 551 | /* hctr2_base(xctr_name, polyval_name) */ |
| 552 | .name = "hctr2_base", |
| 553 | .create = hctr2_create_base, |
| 554 | .module = THIS_MODULE, |
| 555 | }, { |
| 556 | /* hctr2(blockcipher_name) */ |
| 557 | .name = "hctr2", |
| 558 | .create = hctr2_create, |
| 559 | .module = THIS_MODULE, |
| 560 | } |
| 561 | }; |
| 562 | |
| 563 | static int __init hctr2_module_init(void) |
| 564 | { |
| 565 | return crypto_register_templates(hctr2_tmpls, ARRAY_SIZE(hctr2_tmpls)); |
| 566 | } |
| 567 | |
| 568 | static void __exit hctr2_module_exit(void) |
| 569 | { |
| 570 | return crypto_unregister_templates(hctr2_tmpls, |
| 571 | ARRAY_SIZE(hctr2_tmpls)); |
| 572 | } |
| 573 | |
| 574 | subsys_initcall(hctr2_module_init); |
| 575 | module_exit(hctr2_module_exit); |
| 576 | |
| 577 | MODULE_DESCRIPTION("HCTR2 length-preserving encryption mode"); |
| 578 | MODULE_LICENSE("GPL v2"); |
| 579 | MODULE_ALIAS_CRYPTO("hctr2"); |
| 580 | MODULE_IMPORT_NS(CRYPTO_INTERNAL); |