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_ablkcipher *enc; 39 struct crypto_blkcipher *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_ablkcipher *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_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); 86 crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) & 87 CRYPTO_TFM_REQ_MASK); 88 err = crypto_ablkcipher_setkey(enc, keys.enckey, keys.enckeylen); 89 crypto_aead_set_flags(authenc_esn, crypto_ablkcipher_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 struct blkcipher_desc desc = { 186 .tfm = ctx->null, 187 }; 188 189 return crypto_blkcipher_encrypt(&desc, req->dst, req->src, len); 190 } 191 192 static int crypto_authenc_esn_encrypt(struct aead_request *req) 193 { 194 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 195 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 196 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 197 struct ablkcipher_request *abreq = (void *)(areq_ctx->tail 198 + ctx->reqoff); 199 struct crypto_ablkcipher *enc = ctx->enc; 200 unsigned int assoclen = req->assoclen; 201 unsigned int cryptlen = req->cryptlen; 202 struct scatterlist *src, *dst; 203 int err; 204 205 sg_init_table(areq_ctx->src, 2); 206 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen); 207 dst = src; 208 209 if (req->src != req->dst) { 210 err = crypto_authenc_esn_copy(req, assoclen); 211 if (err) 212 return err; 213 214 sg_init_table(areq_ctx->dst, 2); 215 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen); 216 } 217 218 ablkcipher_request_set_tfm(abreq, enc); 219 ablkcipher_request_set_callback(abreq, aead_request_flags(req), 220 crypto_authenc_esn_encrypt_done, req); 221 ablkcipher_request_set_crypt(abreq, src, dst, cryptlen, req->iv); 222 223 err = crypto_ablkcipher_encrypt(abreq); 224 if (err) 225 return err; 226 227 return crypto_authenc_esn_genicv(req, aead_request_flags(req)); 228 } 229 230 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req, 231 unsigned int flags) 232 { 233 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 234 unsigned int authsize = crypto_aead_authsize(authenc_esn); 235 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 236 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 237 struct ablkcipher_request *abreq = (void *)(areq_ctx->tail 238 + ctx->reqoff); 239 struct crypto_ahash *auth = ctx->auth; 240 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, 241 crypto_ahash_alignmask(auth) + 1); 242 unsigned int cryptlen = req->cryptlen - authsize; 243 unsigned int assoclen = req->assoclen; 244 struct scatterlist *dst = req->dst; 245 u8 *ihash = ohash + crypto_ahash_digestsize(auth); 246 u32 tmp[2]; 247 248 /* Move high-order bits of sequence number back. */ 249 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0); 250 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0); 251 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1); 252 253 if (crypto_memneq(ihash, ohash, authsize)) 254 return -EBADMSG; 255 256 sg_init_table(areq_ctx->dst, 2); 257 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen); 258 259 ablkcipher_request_set_tfm(abreq, ctx->enc); 260 ablkcipher_request_set_callback(abreq, flags, 261 req->base.complete, req->base.data); 262 ablkcipher_request_set_crypt(abreq, dst, dst, cryptlen, req->iv); 263 264 return crypto_ablkcipher_decrypt(abreq); 265 } 266 267 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq, 268 int err) 269 { 270 struct aead_request *req = areq->data; 271 272 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0); 273 aead_request_complete(req, err); 274 } 275 276 static int crypto_authenc_esn_decrypt(struct aead_request *req) 277 { 278 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); 279 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); 280 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); 281 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); 282 unsigned int authsize = crypto_aead_authsize(authenc_esn); 283 struct crypto_ahash *auth = ctx->auth; 284 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, 285 crypto_ahash_alignmask(auth) + 1); 286 unsigned int assoclen = req->assoclen; 287 unsigned int cryptlen = req->cryptlen; 288 u8 *ihash = ohash + crypto_ahash_digestsize(auth); 289 struct scatterlist *dst = req->dst; 290 u32 tmp[2]; 291 int err; 292 293 cryptlen -= authsize; 294 295 if (req->src != dst) { 296 err = crypto_authenc_esn_copy(req, assoclen + cryptlen); 297 if (err) 298 return err; 299 } 300 301 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen, 302 authsize, 0); 303 304 if (!authsize) 305 goto tail; 306 307 /* Move high-order bits of sequence number to the end. */ 308 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0); 309 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1); 310 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1); 311 312 sg_init_table(areq_ctx->dst, 2); 313 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4); 314 315 ahash_request_set_tfm(ahreq, auth); 316 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen); 317 ahash_request_set_callback(ahreq, aead_request_flags(req), 318 authenc_esn_verify_ahash_done, req); 319 320 err = crypto_ahash_digest(ahreq); 321 if (err) 322 return err; 323 324 tail: 325 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req)); 326 } 327 328 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm) 329 { 330 struct aead_instance *inst = aead_alg_instance(tfm); 331 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst); 332 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); 333 struct crypto_ahash *auth; 334 struct crypto_ablkcipher *enc; 335 struct crypto_blkcipher *null; 336 int err; 337 338 auth = crypto_spawn_ahash(&ictx->auth); 339 if (IS_ERR(auth)) 340 return PTR_ERR(auth); 341 342 enc = crypto_spawn_skcipher(&ictx->enc); 343 err = PTR_ERR(enc); 344 if (IS_ERR(enc)) 345 goto err_free_ahash; 346 347 null = crypto_get_default_null_skcipher(); 348 err = PTR_ERR(null); 349 if (IS_ERR(null)) 350 goto err_free_skcipher; 351 352 ctx->auth = auth; 353 ctx->enc = enc; 354 ctx->null = null; 355 356 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth), 357 crypto_ahash_alignmask(auth) + 1); 358 359 crypto_aead_set_reqsize( 360 tfm, 361 sizeof(struct authenc_esn_request_ctx) + 362 ctx->reqoff + 363 max_t(unsigned int, 364 crypto_ahash_reqsize(auth) + 365 sizeof(struct ahash_request), 366 sizeof(struct skcipher_givcrypt_request) + 367 crypto_ablkcipher_reqsize(enc))); 368 369 return 0; 370 371 err_free_skcipher: 372 crypto_free_ablkcipher(enc); 373 err_free_ahash: 374 crypto_free_ahash(auth); 375 return err; 376 } 377 378 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm) 379 { 380 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); 381 382 crypto_free_ahash(ctx->auth); 383 crypto_free_ablkcipher(ctx->enc); 384 crypto_put_default_null_skcipher(); 385 } 386 387 static void crypto_authenc_esn_free(struct aead_instance *inst) 388 { 389 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst); 390 391 crypto_drop_skcipher(&ctx->enc); 392 crypto_drop_ahash(&ctx->auth); 393 kfree(inst); 394 } 395 396 static int crypto_authenc_esn_create(struct crypto_template *tmpl, 397 struct rtattr **tb) 398 { 399 struct crypto_attr_type *algt; 400 struct aead_instance *inst; 401 struct hash_alg_common *auth; 402 struct crypto_alg *auth_base; 403 struct crypto_alg *enc; 404 struct authenc_esn_instance_ctx *ctx; 405 const char *enc_name; 406 int err; 407 408 algt = crypto_get_attr_type(tb); 409 if (IS_ERR(algt)) 410 return PTR_ERR(algt); 411 412 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 413 return -EINVAL; 414 415 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 416 CRYPTO_ALG_TYPE_AHASH_MASK); 417 if (IS_ERR(auth)) 418 return PTR_ERR(auth); 419 420 auth_base = &auth->base; 421 422 enc_name = crypto_attr_alg_name(tb[2]); 423 err = PTR_ERR(enc_name); 424 if (IS_ERR(enc_name)) 425 goto out_put_auth; 426 427 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 428 err = -ENOMEM; 429 if (!inst) 430 goto out_put_auth; 431 432 ctx = aead_instance_ctx(inst); 433 434 err = crypto_init_ahash_spawn(&ctx->auth, auth, 435 aead_crypto_instance(inst)); 436 if (err) 437 goto err_free_inst; 438 439 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); 440 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, 441 crypto_requires_sync(algt->type, 442 algt->mask)); 443 if (err) 444 goto err_drop_auth; 445 446 enc = crypto_skcipher_spawn_alg(&ctx->enc); 447 448 err = -ENAMETOOLONG; 449 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 450 "authencesn(%s,%s)", auth_base->cra_name, 451 enc->cra_name) >= CRYPTO_MAX_ALG_NAME) 452 goto err_drop_enc; 453 454 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 455 "authencesn(%s,%s)", auth_base->cra_driver_name, 456 enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 457 goto err_drop_enc; 458 459 inst->alg.base.cra_flags = enc->cra_flags & CRYPTO_ALG_ASYNC; 460 inst->alg.base.cra_priority = enc->cra_priority * 10 + 461 auth_base->cra_priority; 462 inst->alg.base.cra_blocksize = enc->cra_blocksize; 463 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 464 enc->cra_alignmask; 465 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx); 466 467 inst->alg.ivsize = enc->cra_ablkcipher.ivsize; 468 inst->alg.maxauthsize = auth->digestsize; 469 470 inst->alg.init = crypto_authenc_esn_init_tfm; 471 inst->alg.exit = crypto_authenc_esn_exit_tfm; 472 473 inst->alg.setkey = crypto_authenc_esn_setkey; 474 inst->alg.setauthsize = crypto_authenc_esn_setauthsize; 475 inst->alg.encrypt = crypto_authenc_esn_encrypt; 476 inst->alg.decrypt = crypto_authenc_esn_decrypt; 477 478 inst->free = crypto_authenc_esn_free, 479 480 err = aead_register_instance(tmpl, inst); 481 if (err) 482 goto err_drop_enc; 483 484 out: 485 crypto_mod_put(auth_base); 486 return err; 487 488 err_drop_enc: 489 crypto_drop_skcipher(&ctx->enc); 490 err_drop_auth: 491 crypto_drop_ahash(&ctx->auth); 492 err_free_inst: 493 kfree(inst); 494 out_put_auth: 495 goto out; 496 } 497 498 static struct crypto_template crypto_authenc_esn_tmpl = { 499 .name = "authencesn", 500 .create = crypto_authenc_esn_create, 501 .module = THIS_MODULE, 502 }; 503 504 static int __init crypto_authenc_esn_module_init(void) 505 { 506 return crypto_register_template(&crypto_authenc_esn_tmpl); 507 } 508 509 static void __exit crypto_authenc_esn_module_exit(void) 510 { 511 crypto_unregister_template(&crypto_authenc_esn_tmpl); 512 } 513 514 module_init(crypto_authenc_esn_module_init); 515 module_exit(crypto_authenc_esn_module_exit); 516 517 MODULE_LICENSE("GPL"); 518 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 519 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers"); 520 MODULE_ALIAS_CRYPTO("authencesn"); 521