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_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 return err; 112 113 badkey: 114 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); 115 goto out; 116 } 117 118 static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) 119 { 120 struct aead_request *req = areq->data; 121 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 122 struct aead_instance *inst = aead_alg_instance(authenc); 123 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 124 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 125 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 126 127 if (err) 128 goto out; 129 130 scatterwalk_map_and_copy(ahreq->result, req->dst, 131 req->assoclen + req->cryptlen, 132 crypto_aead_authsize(authenc), 1); 133 134 out: 135 aead_request_complete(req, err); 136 } 137 138 static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) 139 { 140 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 141 struct aead_instance *inst = aead_alg_instance(authenc); 142 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 143 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 144 struct crypto_ahash *auth = ctx->auth; 145 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 146 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 147 u8 *hash = areq_ctx->tail; 148 int err; 149 150 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 151 crypto_ahash_alignmask(auth) + 1); 152 153 ahash_request_set_tfm(ahreq, auth); 154 ahash_request_set_crypt(ahreq, req->dst, hash, 155 req->assoclen + req->cryptlen); 156 ahash_request_set_callback(ahreq, flags, 157 authenc_geniv_ahash_done, req); 158 159 err = crypto_ahash_digest(ahreq); 160 if (err) 161 return err; 162 163 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, 164 crypto_aead_authsize(authenc), 1); 165 166 return 0; 167 } 168 169 static void crypto_authenc_encrypt_done(struct crypto_async_request *req, 170 int err) 171 { 172 struct aead_request *areq = req->data; 173 174 if (err) 175 goto out; 176 177 err = crypto_authenc_genicv(areq, 0); 178 179 out: 180 authenc_request_complete(areq, err); 181 } 182 183 static int crypto_authenc_copy_assoc(struct aead_request *req) 184 { 185 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 186 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 187 SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); 188 189 skcipher_request_set_tfm(skreq, ctx->null); 190 skcipher_request_set_callback(skreq, aead_request_flags(req), 191 NULL, NULL); 192 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, 193 NULL); 194 195 return crypto_skcipher_encrypt(skreq); 196 } 197 198 static int crypto_authenc_encrypt(struct aead_request *req) 199 { 200 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 201 struct aead_instance *inst = aead_alg_instance(authenc); 202 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 203 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 204 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 205 struct crypto_skcipher *enc = ctx->enc; 206 unsigned int cryptlen = req->cryptlen; 207 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 208 ictx->reqoff); 209 struct scatterlist *src, *dst; 210 int err; 211 212 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 213 dst = src; 214 215 if (req->src != req->dst) { 216 err = crypto_authenc_copy_assoc(req); 217 if (err) 218 return err; 219 220 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 221 } 222 223 skcipher_request_set_tfm(skreq, enc); 224 skcipher_request_set_callback(skreq, aead_request_flags(req), 225 crypto_authenc_encrypt_done, req); 226 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); 227 228 err = crypto_skcipher_encrypt(skreq); 229 if (err) 230 return err; 231 232 return crypto_authenc_genicv(req, aead_request_flags(req)); 233 } 234 235 static int crypto_authenc_decrypt_tail(struct aead_request *req, 236 unsigned int flags) 237 { 238 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 239 struct aead_instance *inst = aead_alg_instance(authenc); 240 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 241 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 242 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 243 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 244 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 245 ictx->reqoff); 246 unsigned int authsize = crypto_aead_authsize(authenc); 247 u8 *ihash = ahreq->result + authsize; 248 struct scatterlist *src, *dst; 249 250 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); 251 252 if (crypto_memneq(ihash, ahreq->result, authsize)) 253 return -EBADMSG; 254 255 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 256 dst = src; 257 258 if (req->src != req->dst) 259 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 260 261 skcipher_request_set_tfm(skreq, ctx->enc); 262 skcipher_request_set_callback(skreq, aead_request_flags(req), 263 req->base.complete, req->base.data); 264 skcipher_request_set_crypt(skreq, src, dst, 265 req->cryptlen - authsize, req->iv); 266 267 return crypto_skcipher_decrypt(skreq); 268 } 269 270 static void authenc_verify_ahash_done(struct crypto_async_request *areq, 271 int err) 272 { 273 struct aead_request *req = areq->data; 274 275 if (err) 276 goto out; 277 278 err = crypto_authenc_decrypt_tail(req, 0); 279 280 out: 281 authenc_request_complete(req, err); 282 } 283 284 static int crypto_authenc_decrypt(struct aead_request *req) 285 { 286 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 287 unsigned int authsize = crypto_aead_authsize(authenc); 288 struct aead_instance *inst = aead_alg_instance(authenc); 289 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 290 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 291 struct crypto_ahash *auth = ctx->auth; 292 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 293 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 294 u8 *hash = areq_ctx->tail; 295 int err; 296 297 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 298 crypto_ahash_alignmask(auth) + 1); 299 300 ahash_request_set_tfm(ahreq, auth); 301 ahash_request_set_crypt(ahreq, req->src, hash, 302 req->assoclen + req->cryptlen - authsize); 303 ahash_request_set_callback(ahreq, aead_request_flags(req), 304 authenc_verify_ahash_done, req); 305 306 err = crypto_ahash_digest(ahreq); 307 if (err) 308 return err; 309 310 return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); 311 } 312 313 static int crypto_authenc_init_tfm(struct crypto_aead *tfm) 314 { 315 struct aead_instance *inst = aead_alg_instance(tfm); 316 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 317 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 318 struct crypto_ahash *auth; 319 struct crypto_skcipher *enc; 320 struct crypto_skcipher *null; 321 int err; 322 323 auth = crypto_spawn_ahash(&ictx->auth); 324 if (IS_ERR(auth)) 325 return PTR_ERR(auth); 326 327 enc = crypto_spawn_skcipher2(&ictx->enc); 328 err = PTR_ERR(enc); 329 if (IS_ERR(enc)) 330 goto err_free_ahash; 331 332 null = crypto_get_default_null_skcipher2(); 333 err = PTR_ERR(null); 334 if (IS_ERR(null)) 335 goto err_free_skcipher; 336 337 ctx->auth = auth; 338 ctx->enc = enc; 339 ctx->null = null; 340 341 crypto_aead_set_reqsize( 342 tfm, 343 sizeof(struct authenc_request_ctx) + 344 ictx->reqoff + 345 max_t(unsigned int, 346 crypto_ahash_reqsize(auth) + 347 sizeof(struct ahash_request), 348 sizeof(struct skcipher_request) + 349 crypto_skcipher_reqsize(enc))); 350 351 return 0; 352 353 err_free_skcipher: 354 crypto_free_skcipher(enc); 355 err_free_ahash: 356 crypto_free_ahash(auth); 357 return err; 358 } 359 360 static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) 361 { 362 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 363 364 crypto_free_ahash(ctx->auth); 365 crypto_free_skcipher(ctx->enc); 366 crypto_put_default_null_skcipher2(); 367 } 368 369 static void crypto_authenc_free(struct aead_instance *inst) 370 { 371 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); 372 373 crypto_drop_skcipher(&ctx->enc); 374 crypto_drop_ahash(&ctx->auth); 375 kfree(inst); 376 } 377 378 static int crypto_authenc_create(struct crypto_template *tmpl, 379 struct rtattr **tb) 380 { 381 struct crypto_attr_type *algt; 382 struct aead_instance *inst; 383 struct hash_alg_common *auth; 384 struct crypto_alg *auth_base; 385 struct skcipher_alg *enc; 386 struct authenc_instance_ctx *ctx; 387 const char *enc_name; 388 int err; 389 390 algt = crypto_get_attr_type(tb); 391 if (IS_ERR(algt)) 392 return PTR_ERR(algt); 393 394 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 395 return -EINVAL; 396 397 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 398 CRYPTO_ALG_TYPE_AHASH_MASK | 399 crypto_requires_sync(algt->type, algt->mask)); 400 if (IS_ERR(auth)) 401 return PTR_ERR(auth); 402 403 auth_base = &auth->base; 404 405 enc_name = crypto_attr_alg_name(tb[2]); 406 err = PTR_ERR(enc_name); 407 if (IS_ERR(enc_name)) 408 goto out_put_auth; 409 410 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 411 err = -ENOMEM; 412 if (!inst) 413 goto out_put_auth; 414 415 ctx = aead_instance_ctx(inst); 416 417 err = crypto_init_ahash_spawn(&ctx->auth, auth, 418 aead_crypto_instance(inst)); 419 if (err) 420 goto err_free_inst; 421 422 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); 423 err = crypto_grab_skcipher2(&ctx->enc, enc_name, 0, 424 crypto_requires_sync(algt->type, 425 algt->mask)); 426 if (err) 427 goto err_drop_auth; 428 429 enc = crypto_spawn_skcipher_alg(&ctx->enc); 430 431 ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, 432 auth_base->cra_alignmask + 1); 433 434 err = -ENAMETOOLONG; 435 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 436 "authenc(%s,%s)", auth_base->cra_name, 437 enc->base.cra_name) >= 438 CRYPTO_MAX_ALG_NAME) 439 goto err_drop_enc; 440 441 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 442 "authenc(%s,%s)", auth_base->cra_driver_name, 443 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 444 goto err_drop_enc; 445 446 inst->alg.base.cra_flags = (auth_base->cra_flags | 447 enc->base.cra_flags) & CRYPTO_ALG_ASYNC; 448 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 449 auth_base->cra_priority; 450 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 451 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 452 enc->base.cra_alignmask; 453 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); 454 455 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); 456 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); 457 inst->alg.maxauthsize = auth->digestsize; 458 459 inst->alg.init = crypto_authenc_init_tfm; 460 inst->alg.exit = crypto_authenc_exit_tfm; 461 462 inst->alg.setkey = crypto_authenc_setkey; 463 inst->alg.encrypt = crypto_authenc_encrypt; 464 inst->alg.decrypt = crypto_authenc_decrypt; 465 466 inst->free = crypto_authenc_free; 467 468 err = aead_register_instance(tmpl, inst); 469 if (err) 470 goto err_drop_enc; 471 472 out: 473 crypto_mod_put(auth_base); 474 return err; 475 476 err_drop_enc: 477 crypto_drop_skcipher(&ctx->enc); 478 err_drop_auth: 479 crypto_drop_ahash(&ctx->auth); 480 err_free_inst: 481 kfree(inst); 482 out_put_auth: 483 goto out; 484 } 485 486 static struct crypto_template crypto_authenc_tmpl = { 487 .name = "authenc", 488 .create = crypto_authenc_create, 489 .module = THIS_MODULE, 490 }; 491 492 static int __init crypto_authenc_module_init(void) 493 { 494 return crypto_register_template(&crypto_authenc_tmpl); 495 } 496 497 static void __exit crypto_authenc_module_exit(void) 498 { 499 crypto_unregister_template(&crypto_authenc_tmpl); 500 } 501 502 module_init(crypto_authenc_module_init); 503 module_exit(crypto_authenc_module_exit); 504 505 MODULE_LICENSE("GPL"); 506 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); 507 MODULE_ALIAS_CRYPTO("authenc"); 508