1 /* 2 * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers, 3 * derived from authenc.c 4 * 5 * Copyright (C) 2010 secunet Security Networks AG 6 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com> 7 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the Free 11 * Software Foundation; either version 2 of the License, or (at your option) 12 * any later version. 13 * 14 */ 15 16 #include <crypto/internal/aead.h> 17 #include <crypto/internal/hash.h> 18 #include <crypto/internal/skcipher.h> 19 #include <crypto/authenc.h> 20 #include <crypto/null.h> 21 #include <crypto/scatterwalk.h> 22 #include <linux/err.h> 23 #include <linux/init.h> 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/rtnetlink.h> 27 #include <linux/slab.h> 28 #include <linux/spinlock.h> 29 30 struct authenc_esn_instance_ctx { 31 struct crypto_ahash_spawn auth; 32 struct crypto_skcipher_spawn enc; 33 }; 34 35 struct crypto_authenc_esn_ctx { 36 unsigned int reqoff; 37 struct crypto_ahash *auth; 38 struct crypto_skcipher *enc; 39 struct crypto_skcipher *null; 40 }; 41 42 struct authenc_esn_request_ctx { 43 struct scatterlist src[2]; 44 struct scatterlist dst[2]; 45 char tail[]; 46 }; 47 48 static void authenc_esn_request_complete(struct aead_request *req, int err) 49 { 50 if (err != -EINPROGRESS) 51 aead_request_complete(req, err); 52 } 53 54 static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn, 55 unsigned int authsize) 56 { 57 if (authsize > 0 && authsize < 4) 58 return -EINVAL; 59 60 return 0; 61 } 62 63 static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key, 64 unsigned int keylen) 65 { 66 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 67 struct crypto_ahash *auth = ctx->auth; 68 struct crypto_skcipher *enc = ctx->enc; 69 struct crypto_authenc_keys keys; 70 int err = -EINVAL; 71 72 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) 73 goto badkey; 74 75 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); 76 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) & 77 CRYPTO_TFM_REQ_MASK); 78 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); 79 crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) & 80 CRYPTO_TFM_RES_MASK); 81 82 if (err) 83 goto out; 84 85 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); 86 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) & 87 CRYPTO_TFM_REQ_MASK); 88 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); 89 crypto_aead_set_flags(authenc_esn, crypto_skcipher_get_flags(enc) & 90 CRYPTO_TFM_RES_MASK); 91 92 out: 93 return err; 94 95 badkey: 96 crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN); 97 goto out; 98 } 99 100 static int crypto_authenc_esn_genicv_tail(struct aead_request *req, 101 unsigned int flags) 102 { 103 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 104 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 105 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 106 struct crypto_ahash *auth = ctx->auth; 107 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail, 108 crypto_ahash_alignmask(auth) + 1); 109 unsigned int authsize = crypto_aead_authsize(authenc_esn); 110 unsigned int assoclen = req->assoclen; 111 unsigned int cryptlen = req->cryptlen; 112 struct scatterlist *dst = req->dst; 113 u32 tmp[2]; 114 115 /* Move high-order bits of sequence number back. */ 116 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0); 117 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0); 118 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1); 119 120 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1); 121 return 0; 122 } 123 124 static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq, 125 int err) 126 { 127 struct aead_request *req = areq->data; 128 129 err = err ?: crypto_authenc_esn_genicv_tail(req, 0); 130 aead_request_complete(req, err); 131 } 132 133 static int crypto_authenc_esn_genicv(struct aead_request *req, 134 unsigned int flags) 135 { 136 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 137 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 138 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 139 struct crypto_ahash *auth = ctx->auth; 140 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail, 141 crypto_ahash_alignmask(auth) + 1); 142 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); 143 unsigned int authsize = crypto_aead_authsize(authenc_esn); 144 unsigned int assoclen = req->assoclen; 145 unsigned int cryptlen = req->cryptlen; 146 struct scatterlist *dst = req->dst; 147 u32 tmp[2]; 148 149 if (!authsize) 150 return 0; 151 152 /* Move high-order bits of sequence number to the end. */ 153 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0); 154 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1); 155 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1); 156 157 sg_init_table(areq_ctx->dst, 2); 158 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4); 159 160 ahash_request_set_tfm(ahreq, auth); 161 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen); 162 ahash_request_set_callback(ahreq, flags, 163 authenc_esn_geniv_ahash_done, req); 164 165 return crypto_ahash_digest(ahreq) ?: 166 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req)); 167 } 168 169 170 static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req, 171 int err) 172 { 173 struct aead_request *areq = req->data; 174 175 if (!err) 176 err = crypto_authenc_esn_genicv(areq, 0); 177 178 authenc_esn_request_complete(areq, err); 179 } 180 181 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len) 182 { 183 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 184 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 185 SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); 186 187 skcipher_request_set_tfm(skreq, ctx->null); 188 skcipher_request_set_callback(skreq, aead_request_flags(req), 189 NULL, NULL); 190 skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL); 191 192 return crypto_skcipher_encrypt(skreq); 193 } 194 195 static int crypto_authenc_esn_encrypt(struct aead_request *req) 196 { 197 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 198 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 199 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 200 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 201 ctx->reqoff); 202 struct crypto_skcipher *enc = ctx->enc; 203 unsigned int assoclen = req->assoclen; 204 unsigned int cryptlen = req->cryptlen; 205 struct scatterlist *src, *dst; 206 int err; 207 208 sg_init_table(areq_ctx->src, 2); 209 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen); 210 dst = src; 211 212 if (req->src != req->dst) { 213 err = crypto_authenc_esn_copy(req, assoclen); 214 if (err) 215 return err; 216 217 sg_init_table(areq_ctx->dst, 2); 218 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen); 219 } 220 221 skcipher_request_set_tfm(skreq, enc); 222 skcipher_request_set_callback(skreq, aead_request_flags(req), 223 crypto_authenc_esn_encrypt_done, req); 224 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); 225 226 err = crypto_skcipher_encrypt(skreq); 227 if (err) 228 return err; 229 230 return crypto_authenc_esn_genicv(req, aead_request_flags(req)); 231 } 232 233 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req, 234 unsigned int flags) 235 { 236 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 237 unsigned int authsize = crypto_aead_authsize(authenc_esn); 238 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 239 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 240 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 241 ctx->reqoff); 242 struct crypto_ahash *auth = ctx->auth; 243 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, 244 crypto_ahash_alignmask(auth) + 1); 245 unsigned int cryptlen = req->cryptlen - authsize; 246 unsigned int assoclen = req->assoclen; 247 struct scatterlist *dst = req->dst; 248 u8 *ihash = ohash + crypto_ahash_digestsize(auth); 249 u32 tmp[2]; 250 251 if (!authsize) 252 goto decrypt; 253 254 /* Move high-order bits of sequence number back. */ 255 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0); 256 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0); 257 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1); 258 259 if (crypto_memneq(ihash, ohash, authsize)) 260 return -EBADMSG; 261 262 decrypt: 263 264 sg_init_table(areq_ctx->dst, 2); 265 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen); 266 267 skcipher_request_set_tfm(skreq, ctx->enc); 268 skcipher_request_set_callback(skreq, flags, 269 req->base.complete, req->base.data); 270 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv); 271 272 return crypto_skcipher_decrypt(skreq); 273 } 274 275 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq, 276 int err) 277 { 278 struct aead_request *req = areq->data; 279 280 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0); 281 aead_request_complete(req, err); 282 } 283 284 static int crypto_authenc_esn_decrypt(struct aead_request *req) 285 { 286 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 287 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 288 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 289 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); 290 unsigned int authsize = crypto_aead_authsize(authenc_esn); 291 struct crypto_ahash *auth = ctx->auth; 292 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, 293 crypto_ahash_alignmask(auth) + 1); 294 unsigned int assoclen = req->assoclen; 295 unsigned int cryptlen = req->cryptlen; 296 u8 *ihash = ohash + crypto_ahash_digestsize(auth); 297 struct scatterlist *dst = req->dst; 298 u32 tmp[2]; 299 int err; 300 301 cryptlen -= authsize; 302 303 if (req->src != dst) { 304 err = crypto_authenc_esn_copy(req, assoclen + cryptlen); 305 if (err) 306 return err; 307 } 308 309 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen, 310 authsize, 0); 311 312 if (!authsize) 313 goto tail; 314 315 /* Move high-order bits of sequence number to the end. */ 316 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0); 317 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1); 318 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1); 319 320 sg_init_table(areq_ctx->dst, 2); 321 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4); 322 323 ahash_request_set_tfm(ahreq, auth); 324 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen); 325 ahash_request_set_callback(ahreq, aead_request_flags(req), 326 authenc_esn_verify_ahash_done, req); 327 328 err = crypto_ahash_digest(ahreq); 329 if (err) 330 return err; 331 332 tail: 333 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req)); 334 } 335 336 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm) 337 { 338 struct aead_instance *inst = aead_alg_instance(tfm); 339 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst); 340 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); 341 struct crypto_ahash *auth; 342 struct crypto_skcipher *enc; 343 struct crypto_skcipher *null; 344 int err; 345 346 auth = crypto_spawn_ahash(&ictx->auth); 347 if (IS_ERR(auth)) 348 return PTR_ERR(auth); 349 350 enc = crypto_spawn_skcipher(&ictx->enc); 351 err = PTR_ERR(enc); 352 if (IS_ERR(enc)) 353 goto err_free_ahash; 354 355 null = crypto_get_default_null_skcipher2(); 356 err = PTR_ERR(null); 357 if (IS_ERR(null)) 358 goto err_free_skcipher; 359 360 ctx->auth = auth; 361 ctx->enc = enc; 362 ctx->null = null; 363 364 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth), 365 crypto_ahash_alignmask(auth) + 1); 366 367 crypto_aead_set_reqsize( 368 tfm, 369 sizeof(struct authenc_esn_request_ctx) + 370 ctx->reqoff + 371 max_t(unsigned int, 372 crypto_ahash_reqsize(auth) + 373 sizeof(struct ahash_request), 374 sizeof(struct skcipher_request) + 375 crypto_skcipher_reqsize(enc))); 376 377 return 0; 378 379 err_free_skcipher: 380 crypto_free_skcipher(enc); 381 err_free_ahash: 382 crypto_free_ahash(auth); 383 return err; 384 } 385 386 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm) 387 { 388 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); 389 390 crypto_free_ahash(ctx->auth); 391 crypto_free_skcipher(ctx->enc); 392 crypto_put_default_null_skcipher2(); 393 } 394 395 static void crypto_authenc_esn_free(struct aead_instance *inst) 396 { 397 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst); 398 399 crypto_drop_skcipher(&ctx->enc); 400 crypto_drop_ahash(&ctx->auth); 401 kfree(inst); 402 } 403 404 static int crypto_authenc_esn_create(struct crypto_template *tmpl, 405 struct rtattr **tb) 406 { 407 struct crypto_attr_type *algt; 408 struct aead_instance *inst; 409 struct hash_alg_common *auth; 410 struct crypto_alg *auth_base; 411 struct skcipher_alg *enc; 412 struct authenc_esn_instance_ctx *ctx; 413 const char *enc_name; 414 int err; 415 416 algt = crypto_get_attr_type(tb); 417 if (IS_ERR(algt)) 418 return PTR_ERR(algt); 419 420 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 421 return -EINVAL; 422 423 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 424 CRYPTO_ALG_TYPE_AHASH_MASK | 425 crypto_requires_sync(algt->type, algt->mask)); 426 if (IS_ERR(auth)) 427 return PTR_ERR(auth); 428 429 auth_base = &auth->base; 430 431 enc_name = crypto_attr_alg_name(tb[2]); 432 err = PTR_ERR(enc_name); 433 if (IS_ERR(enc_name)) 434 goto out_put_auth; 435 436 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 437 err = -ENOMEM; 438 if (!inst) 439 goto out_put_auth; 440 441 ctx = aead_instance_ctx(inst); 442 443 err = crypto_init_ahash_spawn(&ctx->auth, auth, 444 aead_crypto_instance(inst)); 445 if (err) 446 goto err_free_inst; 447 448 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); 449 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, 450 crypto_requires_sync(algt->type, 451 algt->mask)); 452 if (err) 453 goto err_drop_auth; 454 455 enc = crypto_spawn_skcipher_alg(&ctx->enc); 456 457 err = -ENAMETOOLONG; 458 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 459 "authencesn(%s,%s)", auth_base->cra_name, 460 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME) 461 goto err_drop_enc; 462 463 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 464 "authencesn(%s,%s)", auth_base->cra_driver_name, 465 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 466 goto err_drop_enc; 467 468 inst->alg.base.cra_flags = (auth_base->cra_flags | 469 enc->base.cra_flags) & CRYPTO_ALG_ASYNC; 470 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 471 auth_base->cra_priority; 472 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 473 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 474 enc->base.cra_alignmask; 475 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx); 476 477 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); 478 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); 479 inst->alg.maxauthsize = auth->digestsize; 480 481 inst->alg.init = crypto_authenc_esn_init_tfm; 482 inst->alg.exit = crypto_authenc_esn_exit_tfm; 483 484 inst->alg.setkey = crypto_authenc_esn_setkey; 485 inst->alg.setauthsize = crypto_authenc_esn_setauthsize; 486 inst->alg.encrypt = crypto_authenc_esn_encrypt; 487 inst->alg.decrypt = crypto_authenc_esn_decrypt; 488 489 inst->free = crypto_authenc_esn_free, 490 491 err = aead_register_instance(tmpl, inst); 492 if (err) 493 goto err_drop_enc; 494 495 out: 496 crypto_mod_put(auth_base); 497 return err; 498 499 err_drop_enc: 500 crypto_drop_skcipher(&ctx->enc); 501 err_drop_auth: 502 crypto_drop_ahash(&ctx->auth); 503 err_free_inst: 504 kfree(inst); 505 out_put_auth: 506 goto out; 507 } 508 509 static struct crypto_template crypto_authenc_esn_tmpl = { 510 .name = "authencesn", 511 .create = crypto_authenc_esn_create, 512 .module = THIS_MODULE, 513 }; 514 515 static int __init crypto_authenc_esn_module_init(void) 516 { 517 return crypto_register_template(&crypto_authenc_esn_tmpl); 518 } 519 520 static void __exit crypto_authenc_esn_module_exit(void) 521 { 522 crypto_unregister_template(&crypto_authenc_esn_tmpl); 523 } 524 525 module_init(crypto_authenc_esn_module_init); 526 module_exit(crypto_authenc_esn_module_exit); 527 528 MODULE_LICENSE("GPL"); 529 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 530 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers"); 531 MODULE_ALIAS_CRYPTO("authencesn"); 532