1 /* 2 * Authenc: Simple AEAD wrapper for IPsec 3 * 4 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the Free 8 * Software Foundation; either version 2 of the License, or (at your option) 9 * any later version. 10 * 11 */ 12 13 #include <crypto/internal/aead.h> 14 #include <crypto/internal/hash.h> 15 #include <crypto/internal/skcipher.h> 16 #include <crypto/authenc.h> 17 #include <crypto/null.h> 18 #include <crypto/scatterwalk.h> 19 #include <linux/err.h> 20 #include <linux/init.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/rtnetlink.h> 24 #include <linux/slab.h> 25 #include <linux/spinlock.h> 26 27 struct authenc_instance_ctx { 28 struct crypto_ahash_spawn auth; 29 struct crypto_skcipher_spawn enc; 30 unsigned int reqoff; 31 }; 32 33 struct crypto_authenc_ctx { 34 struct crypto_ahash *auth; 35 struct crypto_skcipher *enc; 36 struct crypto_sync_skcipher *null; 37 }; 38 39 struct authenc_request_ctx { 40 struct scatterlist src[2]; 41 struct scatterlist dst[2]; 42 char tail[]; 43 }; 44 45 static void authenc_request_complete(struct aead_request *req, int err) 46 { 47 if (err != -EINPROGRESS) 48 aead_request_complete(req, err); 49 } 50 51 int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key, 52 unsigned int keylen) 53 { 54 struct rtattr *rta = (struct rtattr *)key; 55 struct crypto_authenc_key_param *param; 56 57 if (!RTA_OK(rta, keylen)) 58 return -EINVAL; 59 if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) 60 return -EINVAL; 61 if (RTA_PAYLOAD(rta) < sizeof(*param)) 62 return -EINVAL; 63 64 param = RTA_DATA(rta); 65 keys->enckeylen = be32_to_cpu(param->enckeylen); 66 67 key += RTA_ALIGN(rta->rta_len); 68 keylen -= RTA_ALIGN(rta->rta_len); 69 70 if (keylen < keys->enckeylen) 71 return -EINVAL; 72 73 keys->authkeylen = keylen - keys->enckeylen; 74 keys->authkey = key; 75 keys->enckey = key + keys->authkeylen; 76 77 return 0; 78 } 79 EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); 80 81 static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, 82 unsigned int keylen) 83 { 84 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 85 struct crypto_ahash *auth = ctx->auth; 86 struct crypto_skcipher *enc = ctx->enc; 87 struct crypto_authenc_keys keys; 88 int err = -EINVAL; 89 90 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) 91 goto badkey; 92 93 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); 94 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) & 95 CRYPTO_TFM_REQ_MASK); 96 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); 97 crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) & 98 CRYPTO_TFM_RES_MASK); 99 100 if (err) 101 goto out; 102 103 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); 104 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & 105 CRYPTO_TFM_REQ_MASK); 106 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); 107 crypto_aead_set_flags(authenc, crypto_skcipher_get_flags(enc) & 108 CRYPTO_TFM_RES_MASK); 109 110 out: 111 memzero_explicit(&keys, sizeof(keys)); 112 return err; 113 114 badkey: 115 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); 116 goto out; 117 } 118 119 static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) 120 { 121 struct aead_request *req = areq->data; 122 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 123 struct aead_instance *inst = aead_alg_instance(authenc); 124 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 125 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 126 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 127 128 if (err) 129 goto out; 130 131 scatterwalk_map_and_copy(ahreq->result, req->dst, 132 req->assoclen + req->cryptlen, 133 crypto_aead_authsize(authenc), 1); 134 135 out: 136 aead_request_complete(req, err); 137 } 138 139 static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) 140 { 141 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 142 struct aead_instance *inst = aead_alg_instance(authenc); 143 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 144 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 145 struct crypto_ahash *auth = ctx->auth; 146 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 147 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 148 u8 *hash = areq_ctx->tail; 149 int err; 150 151 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 152 crypto_ahash_alignmask(auth) + 1); 153 154 ahash_request_set_tfm(ahreq, auth); 155 ahash_request_set_crypt(ahreq, req->dst, hash, 156 req->assoclen + req->cryptlen); 157 ahash_request_set_callback(ahreq, flags, 158 authenc_geniv_ahash_done, req); 159 160 err = crypto_ahash_digest(ahreq); 161 if (err) 162 return err; 163 164 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, 165 crypto_aead_authsize(authenc), 1); 166 167 return 0; 168 } 169 170 static void crypto_authenc_encrypt_done(struct crypto_async_request *req, 171 int err) 172 { 173 struct aead_request *areq = req->data; 174 175 if (err) 176 goto out; 177 178 err = crypto_authenc_genicv(areq, 0); 179 180 out: 181 authenc_request_complete(areq, err); 182 } 183 184 static int crypto_authenc_copy_assoc(struct aead_request *req) 185 { 186 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 187 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 188 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); 189 190 skcipher_request_set_sync_tfm(skreq, ctx->null); 191 skcipher_request_set_callback(skreq, aead_request_flags(req), 192 NULL, NULL); 193 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, 194 NULL); 195 196 return crypto_skcipher_encrypt(skreq); 197 } 198 199 static int crypto_authenc_encrypt(struct aead_request *req) 200 { 201 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 202 struct aead_instance *inst = aead_alg_instance(authenc); 203 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 204 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 205 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 206 struct crypto_skcipher *enc = ctx->enc; 207 unsigned int cryptlen = req->cryptlen; 208 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 209 ictx->reqoff); 210 struct scatterlist *src, *dst; 211 int err; 212 213 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 214 dst = src; 215 216 if (req->src != req->dst) { 217 err = crypto_authenc_copy_assoc(req); 218 if (err) 219 return err; 220 221 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 222 } 223 224 skcipher_request_set_tfm(skreq, enc); 225 skcipher_request_set_callback(skreq, aead_request_flags(req), 226 crypto_authenc_encrypt_done, req); 227 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); 228 229 err = crypto_skcipher_encrypt(skreq); 230 if (err) 231 return err; 232 233 return crypto_authenc_genicv(req, aead_request_flags(req)); 234 } 235 236 static int crypto_authenc_decrypt_tail(struct aead_request *req, 237 unsigned int flags) 238 { 239 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 240 struct aead_instance *inst = aead_alg_instance(authenc); 241 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 242 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 243 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 244 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 245 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 246 ictx->reqoff); 247 unsigned int authsize = crypto_aead_authsize(authenc); 248 u8 *ihash = ahreq->result + authsize; 249 struct scatterlist *src, *dst; 250 251 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); 252 253 if (crypto_memneq(ihash, ahreq->result, authsize)) 254 return -EBADMSG; 255 256 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 257 dst = src; 258 259 if (req->src != req->dst) 260 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 261 262 skcipher_request_set_tfm(skreq, ctx->enc); 263 skcipher_request_set_callback(skreq, aead_request_flags(req), 264 req->base.complete, req->base.data); 265 skcipher_request_set_crypt(skreq, src, dst, 266 req->cryptlen - authsize, req->iv); 267 268 return crypto_skcipher_decrypt(skreq); 269 } 270 271 static void authenc_verify_ahash_done(struct crypto_async_request *areq, 272 int err) 273 { 274 struct aead_request *req = areq->data; 275 276 if (err) 277 goto out; 278 279 err = crypto_authenc_decrypt_tail(req, 0); 280 281 out: 282 authenc_request_complete(req, err); 283 } 284 285 static int crypto_authenc_decrypt(struct aead_request *req) 286 { 287 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 288 unsigned int authsize = crypto_aead_authsize(authenc); 289 struct aead_instance *inst = aead_alg_instance(authenc); 290 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 291 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 292 struct crypto_ahash *auth = ctx->auth; 293 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 294 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 295 u8 *hash = areq_ctx->tail; 296 int err; 297 298 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 299 crypto_ahash_alignmask(auth) + 1); 300 301 ahash_request_set_tfm(ahreq, auth); 302 ahash_request_set_crypt(ahreq, req->src, hash, 303 req->assoclen + req->cryptlen - authsize); 304 ahash_request_set_callback(ahreq, aead_request_flags(req), 305 authenc_verify_ahash_done, req); 306 307 err = crypto_ahash_digest(ahreq); 308 if (err) 309 return err; 310 311 return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); 312 } 313 314 static int crypto_authenc_init_tfm(struct crypto_aead *tfm) 315 { 316 struct aead_instance *inst = aead_alg_instance(tfm); 317 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 318 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 319 struct crypto_ahash *auth; 320 struct crypto_skcipher *enc; 321 struct crypto_sync_skcipher *null; 322 int err; 323 324 auth = crypto_spawn_ahash(&ictx->auth); 325 if (IS_ERR(auth)) 326 return PTR_ERR(auth); 327 328 enc = crypto_spawn_skcipher(&ictx->enc); 329 err = PTR_ERR(enc); 330 if (IS_ERR(enc)) 331 goto err_free_ahash; 332 333 null = crypto_get_default_null_skcipher(); 334 err = PTR_ERR(null); 335 if (IS_ERR(null)) 336 goto err_free_skcipher; 337 338 ctx->auth = auth; 339 ctx->enc = enc; 340 ctx->null = null; 341 342 crypto_aead_set_reqsize( 343 tfm, 344 sizeof(struct authenc_request_ctx) + 345 ictx->reqoff + 346 max_t(unsigned int, 347 crypto_ahash_reqsize(auth) + 348 sizeof(struct ahash_request), 349 sizeof(struct skcipher_request) + 350 crypto_skcipher_reqsize(enc))); 351 352 return 0; 353 354 err_free_skcipher: 355 crypto_free_skcipher(enc); 356 err_free_ahash: 357 crypto_free_ahash(auth); 358 return err; 359 } 360 361 static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) 362 { 363 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 364 365 crypto_free_ahash(ctx->auth); 366 crypto_free_skcipher(ctx->enc); 367 crypto_put_default_null_skcipher(); 368 } 369 370 static void crypto_authenc_free(struct aead_instance *inst) 371 { 372 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); 373 374 crypto_drop_skcipher(&ctx->enc); 375 crypto_drop_ahash(&ctx->auth); 376 kfree(inst); 377 } 378 379 static int crypto_authenc_create(struct crypto_template *tmpl, 380 struct rtattr **tb) 381 { 382 struct crypto_attr_type *algt; 383 struct aead_instance *inst; 384 struct hash_alg_common *auth; 385 struct crypto_alg *auth_base; 386 struct skcipher_alg *enc; 387 struct authenc_instance_ctx *ctx; 388 const char *enc_name; 389 int err; 390 391 algt = crypto_get_attr_type(tb); 392 if (IS_ERR(algt)) 393 return PTR_ERR(algt); 394 395 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 396 return -EINVAL; 397 398 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 399 CRYPTO_ALG_TYPE_AHASH_MASK | 400 crypto_requires_sync(algt->type, algt->mask)); 401 if (IS_ERR(auth)) 402 return PTR_ERR(auth); 403 404 auth_base = &auth->base; 405 406 enc_name = crypto_attr_alg_name(tb[2]); 407 err = PTR_ERR(enc_name); 408 if (IS_ERR(enc_name)) 409 goto out_put_auth; 410 411 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 412 err = -ENOMEM; 413 if (!inst) 414 goto out_put_auth; 415 416 ctx = aead_instance_ctx(inst); 417 418 err = crypto_init_ahash_spawn(&ctx->auth, auth, 419 aead_crypto_instance(inst)); 420 if (err) 421 goto err_free_inst; 422 423 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); 424 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, 425 crypto_requires_sync(algt->type, 426 algt->mask)); 427 if (err) 428 goto err_drop_auth; 429 430 enc = crypto_spawn_skcipher_alg(&ctx->enc); 431 432 ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, 433 auth_base->cra_alignmask + 1); 434 435 err = -ENAMETOOLONG; 436 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 437 "authenc(%s,%s)", auth_base->cra_name, 438 enc->base.cra_name) >= 439 CRYPTO_MAX_ALG_NAME) 440 goto err_drop_enc; 441 442 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 443 "authenc(%s,%s)", auth_base->cra_driver_name, 444 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 445 goto err_drop_enc; 446 447 inst->alg.base.cra_flags = (auth_base->cra_flags | 448 enc->base.cra_flags) & CRYPTO_ALG_ASYNC; 449 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 450 auth_base->cra_priority; 451 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 452 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 453 enc->base.cra_alignmask; 454 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); 455 456 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); 457 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); 458 inst->alg.maxauthsize = auth->digestsize; 459 460 inst->alg.init = crypto_authenc_init_tfm; 461 inst->alg.exit = crypto_authenc_exit_tfm; 462 463 inst->alg.setkey = crypto_authenc_setkey; 464 inst->alg.encrypt = crypto_authenc_encrypt; 465 inst->alg.decrypt = crypto_authenc_decrypt; 466 467 inst->free = crypto_authenc_free; 468 469 err = aead_register_instance(tmpl, inst); 470 if (err) 471 goto err_drop_enc; 472 473 out: 474 crypto_mod_put(auth_base); 475 return err; 476 477 err_drop_enc: 478 crypto_drop_skcipher(&ctx->enc); 479 err_drop_auth: 480 crypto_drop_ahash(&ctx->auth); 481 err_free_inst: 482 kfree(inst); 483 out_put_auth: 484 goto out; 485 } 486 487 static struct crypto_template crypto_authenc_tmpl = { 488 .name = "authenc", 489 .create = crypto_authenc_create, 490 .module = THIS_MODULE, 491 }; 492 493 static int __init crypto_authenc_module_init(void) 494 { 495 return crypto_register_template(&crypto_authenc_tmpl); 496 } 497 498 static void __exit crypto_authenc_module_exit(void) 499 { 500 crypto_unregister_template(&crypto_authenc_tmpl); 501 } 502 503 module_init(crypto_authenc_module_init); 504 module_exit(crypto_authenc_module_exit); 505 506 MODULE_LICENSE("GPL"); 507 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); 508 MODULE_ALIAS_CRYPTO("authenc"); 509