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 /* Move high-order bits of sequence number back. */ 252 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0); 253 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0); 254 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1); 255 256 if (crypto_memneq(ihash, ohash, authsize)) 257 return -EBADMSG; 258 259 sg_init_table(areq_ctx->dst, 2); 260 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen); 261 262 skcipher_request_set_tfm(skreq, ctx->enc); 263 skcipher_request_set_callback(skreq, flags, 264 req->base.complete, req->base.data); 265 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv); 266 267 return crypto_skcipher_decrypt(skreq); 268 } 269 270 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq, 271 int err) 272 { 273 struct aead_request *req = areq->data; 274 275 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0); 276 aead_request_complete(req, err); 277 } 278 279 static int crypto_authenc_esn_decrypt(struct aead_request *req) 280 { 281 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 282 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 283 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 284 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); 285 unsigned int authsize = crypto_aead_authsize(authenc_esn); 286 struct crypto_ahash *auth = ctx->auth; 287 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, 288 crypto_ahash_alignmask(auth) + 1); 289 unsigned int assoclen = req->assoclen; 290 unsigned int cryptlen = req->cryptlen; 291 u8 *ihash = ohash + crypto_ahash_digestsize(auth); 292 struct scatterlist *dst = req->dst; 293 u32 tmp[2]; 294 int err; 295 296 cryptlen -= authsize; 297 298 if (req->src != dst) { 299 err = crypto_authenc_esn_copy(req, assoclen + cryptlen); 300 if (err) 301 return err; 302 } 303 304 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen, 305 authsize, 0); 306 307 if (!authsize) 308 goto tail; 309 310 /* Move high-order bits of sequence number to the end. */ 311 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0); 312 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1); 313 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1); 314 315 sg_init_table(areq_ctx->dst, 2); 316 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4); 317 318 ahash_request_set_tfm(ahreq, auth); 319 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen); 320 ahash_request_set_callback(ahreq, aead_request_flags(req), 321 authenc_esn_verify_ahash_done, req); 322 323 err = crypto_ahash_digest(ahreq); 324 if (err) 325 return err; 326 327 tail: 328 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req)); 329 } 330 331 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm) 332 { 333 struct aead_instance *inst = aead_alg_instance(tfm); 334 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst); 335 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); 336 struct crypto_ahash *auth; 337 struct crypto_skcipher *enc; 338 struct crypto_skcipher *null; 339 int err; 340 341 auth = crypto_spawn_ahash(&ictx->auth); 342 if (IS_ERR(auth)) 343 return PTR_ERR(auth); 344 345 enc = crypto_spawn_skcipher(&ictx->enc); 346 err = PTR_ERR(enc); 347 if (IS_ERR(enc)) 348 goto err_free_ahash; 349 350 null = crypto_get_default_null_skcipher2(); 351 err = PTR_ERR(null); 352 if (IS_ERR(null)) 353 goto err_free_skcipher; 354 355 ctx->auth = auth; 356 ctx->enc = enc; 357 ctx->null = null; 358 359 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth), 360 crypto_ahash_alignmask(auth) + 1); 361 362 crypto_aead_set_reqsize( 363 tfm, 364 sizeof(struct authenc_esn_request_ctx) + 365 ctx->reqoff + 366 max_t(unsigned int, 367 crypto_ahash_reqsize(auth) + 368 sizeof(struct ahash_request), 369 sizeof(struct skcipher_request) + 370 crypto_skcipher_reqsize(enc))); 371 372 return 0; 373 374 err_free_skcipher: 375 crypto_free_skcipher(enc); 376 err_free_ahash: 377 crypto_free_ahash(auth); 378 return err; 379 } 380 381 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm) 382 { 383 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); 384 385 crypto_free_ahash(ctx->auth); 386 crypto_free_skcipher(ctx->enc); 387 crypto_put_default_null_skcipher2(); 388 } 389 390 static void crypto_authenc_esn_free(struct aead_instance *inst) 391 { 392 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst); 393 394 crypto_drop_skcipher(&ctx->enc); 395 crypto_drop_ahash(&ctx->auth); 396 kfree(inst); 397 } 398 399 static int crypto_authenc_esn_create(struct crypto_template *tmpl, 400 struct rtattr **tb) 401 { 402 struct crypto_attr_type *algt; 403 struct aead_instance *inst; 404 struct hash_alg_common *auth; 405 struct crypto_alg *auth_base; 406 struct skcipher_alg *enc; 407 struct authenc_esn_instance_ctx *ctx; 408 const char *enc_name; 409 int err; 410 411 algt = crypto_get_attr_type(tb); 412 if (IS_ERR(algt)) 413 return PTR_ERR(algt); 414 415 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 416 return -EINVAL; 417 418 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 419 CRYPTO_ALG_TYPE_AHASH_MASK | 420 crypto_requires_sync(algt->type, algt->mask)); 421 if (IS_ERR(auth)) 422 return PTR_ERR(auth); 423 424 auth_base = &auth->base; 425 426 enc_name = crypto_attr_alg_name(tb[2]); 427 err = PTR_ERR(enc_name); 428 if (IS_ERR(enc_name)) 429 goto out_put_auth; 430 431 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 432 err = -ENOMEM; 433 if (!inst) 434 goto out_put_auth; 435 436 ctx = aead_instance_ctx(inst); 437 438 err = crypto_init_ahash_spawn(&ctx->auth, auth, 439 aead_crypto_instance(inst)); 440 if (err) 441 goto err_free_inst; 442 443 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); 444 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, 445 crypto_requires_sync(algt->type, 446 algt->mask)); 447 if (err) 448 goto err_drop_auth; 449 450 enc = crypto_spawn_skcipher_alg(&ctx->enc); 451 452 err = -ENAMETOOLONG; 453 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 454 "authencesn(%s,%s)", auth_base->cra_name, 455 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME) 456 goto err_drop_enc; 457 458 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 459 "authencesn(%s,%s)", auth_base->cra_driver_name, 460 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 461 goto err_drop_enc; 462 463 inst->alg.base.cra_flags = (auth_base->cra_flags | 464 enc->base.cra_flags) & CRYPTO_ALG_ASYNC; 465 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 466 auth_base->cra_priority; 467 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 468 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 469 enc->base.cra_alignmask; 470 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx); 471 472 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); 473 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); 474 inst->alg.maxauthsize = auth->digestsize; 475 476 inst->alg.init = crypto_authenc_esn_init_tfm; 477 inst->alg.exit = crypto_authenc_esn_exit_tfm; 478 479 inst->alg.setkey = crypto_authenc_esn_setkey; 480 inst->alg.setauthsize = crypto_authenc_esn_setauthsize; 481 inst->alg.encrypt = crypto_authenc_esn_encrypt; 482 inst->alg.decrypt = crypto_authenc_esn_decrypt; 483 484 inst->free = crypto_authenc_esn_free, 485 486 err = aead_register_instance(tmpl, inst); 487 if (err) 488 goto err_drop_enc; 489 490 out: 491 crypto_mod_put(auth_base); 492 return err; 493 494 err_drop_enc: 495 crypto_drop_skcipher(&ctx->enc); 496 err_drop_auth: 497 crypto_drop_ahash(&ctx->auth); 498 err_free_inst: 499 kfree(inst); 500 out_put_auth: 501 goto out; 502 } 503 504 static struct crypto_template crypto_authenc_esn_tmpl = { 505 .name = "authencesn", 506 .create = crypto_authenc_esn_create, 507 .module = THIS_MODULE, 508 }; 509 510 static int __init crypto_authenc_esn_module_init(void) 511 { 512 return crypto_register_template(&crypto_authenc_esn_tmpl); 513 } 514 515 static void __exit crypto_authenc_esn_module_exit(void) 516 { 517 crypto_unregister_template(&crypto_authenc_esn_tmpl); 518 } 519 520 module_init(crypto_authenc_esn_module_init); 521 module_exit(crypto_authenc_esn_module_exit); 522 523 MODULE_LICENSE("GPL"); 524 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 525 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers"); 526 MODULE_ALIAS_CRYPTO("authencesn"); 527