1 /* 2 * Authenc: Simple AEAD wrapper for IPsec 3 * 4 * Copyright (c) 2007 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/aead.h> 14 #include <crypto/internal/hash.h> 15 #include <crypto/internal/skcipher.h> 16 #include <crypto/authenc.h> 17 #include <crypto/scatterwalk.h> 18 #include <linux/err.h> 19 #include <linux/init.h> 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/rtnetlink.h> 23 #include <linux/slab.h> 24 #include <linux/spinlock.h> 25 26 struct authenc_instance_ctx { 27 struct crypto_spawn auth; 28 struct crypto_skcipher_spawn enc; 29 }; 30 31 struct crypto_authenc_ctx { 32 spinlock_t auth_lock; 33 struct crypto_hash *auth; 34 struct crypto_ablkcipher *enc; 35 }; 36 37 static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, 38 unsigned int keylen) 39 { 40 unsigned int authkeylen; 41 unsigned int enckeylen; 42 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 43 struct crypto_hash *auth = ctx->auth; 44 struct crypto_ablkcipher *enc = ctx->enc; 45 struct rtattr *rta = (void *)key; 46 struct crypto_authenc_key_param *param; 47 int err = -EINVAL; 48 49 if (!RTA_OK(rta, keylen)) 50 goto badkey; 51 if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) 52 goto badkey; 53 if (RTA_PAYLOAD(rta) < sizeof(*param)) 54 goto badkey; 55 56 param = RTA_DATA(rta); 57 enckeylen = be32_to_cpu(param->enckeylen); 58 59 key += RTA_ALIGN(rta->rta_len); 60 keylen -= RTA_ALIGN(rta->rta_len); 61 62 if (keylen < enckeylen) 63 goto badkey; 64 65 authkeylen = keylen - enckeylen; 66 67 crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); 68 crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) & 69 CRYPTO_TFM_REQ_MASK); 70 err = crypto_hash_setkey(auth, key, authkeylen); 71 crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) & 72 CRYPTO_TFM_RES_MASK); 73 74 if (err) 75 goto out; 76 77 crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); 78 crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) & 79 CRYPTO_TFM_REQ_MASK); 80 err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen); 81 crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) & 82 CRYPTO_TFM_RES_MASK); 83 84 out: 85 return err; 86 87 badkey: 88 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); 89 goto out; 90 } 91 92 static void authenc_chain(struct scatterlist *head, struct scatterlist *sg, 93 int chain) 94 { 95 if (chain) { 96 head->length += sg->length; 97 sg = scatterwalk_sg_next(sg); 98 } 99 100 if (sg) 101 scatterwalk_sg_chain(head, 2, sg); 102 else 103 sg_mark_end(head); 104 } 105 106 static u8 *crypto_authenc_hash(struct aead_request *req, unsigned int flags, 107 struct scatterlist *cipher, 108 unsigned int cryptlen) 109 { 110 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 111 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 112 struct crypto_hash *auth = ctx->auth; 113 struct hash_desc desc = { 114 .tfm = auth, 115 .flags = aead_request_flags(req) & flags, 116 }; 117 u8 *hash = aead_request_ctx(req); 118 int err; 119 120 hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth), 121 crypto_hash_alignmask(auth) + 1); 122 123 spin_lock_bh(&ctx->auth_lock); 124 err = crypto_hash_init(&desc); 125 if (err) 126 goto auth_unlock; 127 128 err = crypto_hash_update(&desc, req->assoc, req->assoclen); 129 if (err) 130 goto auth_unlock; 131 132 err = crypto_hash_update(&desc, cipher, cryptlen); 133 if (err) 134 goto auth_unlock; 135 136 err = crypto_hash_final(&desc, hash); 137 auth_unlock: 138 spin_unlock_bh(&ctx->auth_lock); 139 140 if (err) 141 return ERR_PTR(err); 142 143 return hash; 144 } 145 146 static int crypto_authenc_genicv(struct aead_request *req, u8 *iv, 147 unsigned int flags) 148 { 149 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 150 struct scatterlist *dst = req->dst; 151 struct scatterlist cipher[2]; 152 struct page *dstp; 153 unsigned int ivsize = crypto_aead_ivsize(authenc); 154 unsigned int cryptlen; 155 u8 *vdst; 156 u8 *hash; 157 158 dstp = sg_page(dst); 159 vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset; 160 161 if (ivsize) { 162 sg_init_table(cipher, 2); 163 sg_set_buf(cipher, iv, ivsize); 164 authenc_chain(cipher, dst, vdst == iv + ivsize); 165 dst = cipher; 166 } 167 168 cryptlen = req->cryptlen + ivsize; 169 hash = crypto_authenc_hash(req, flags, dst, cryptlen); 170 if (IS_ERR(hash)) 171 return PTR_ERR(hash); 172 173 scatterwalk_map_and_copy(hash, dst, cryptlen, 174 crypto_aead_authsize(authenc), 1); 175 return 0; 176 } 177 178 static void crypto_authenc_encrypt_done(struct crypto_async_request *req, 179 int err) 180 { 181 struct aead_request *areq = req->data; 182 183 if (!err) { 184 struct crypto_aead *authenc = crypto_aead_reqtfm(areq); 185 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 186 struct ablkcipher_request *abreq = aead_request_ctx(areq); 187 u8 *iv = (u8 *)(abreq + 1) + 188 crypto_ablkcipher_reqsize(ctx->enc); 189 190 err = crypto_authenc_genicv(areq, iv, 0); 191 } 192 193 aead_request_complete(areq, err); 194 } 195 196 static int crypto_authenc_encrypt(struct aead_request *req) 197 { 198 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 199 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 200 struct ablkcipher_request *abreq = aead_request_ctx(req); 201 struct crypto_ablkcipher *enc = ctx->enc; 202 struct scatterlist *dst = req->dst; 203 unsigned int cryptlen = req->cryptlen; 204 u8 *iv = (u8 *)(abreq + 1) + crypto_ablkcipher_reqsize(enc); 205 int err; 206 207 ablkcipher_request_set_tfm(abreq, enc); 208 ablkcipher_request_set_callback(abreq, aead_request_flags(req), 209 crypto_authenc_encrypt_done, req); 210 ablkcipher_request_set_crypt(abreq, req->src, dst, cryptlen, req->iv); 211 212 memcpy(iv, req->iv, crypto_aead_ivsize(authenc)); 213 214 err = crypto_ablkcipher_encrypt(abreq); 215 if (err) 216 return err; 217 218 return crypto_authenc_genicv(req, iv, CRYPTO_TFM_REQ_MAY_SLEEP); 219 } 220 221 static void crypto_authenc_givencrypt_done(struct crypto_async_request *req, 222 int err) 223 { 224 struct aead_request *areq = req->data; 225 226 if (!err) { 227 struct skcipher_givcrypt_request *greq = aead_request_ctx(areq); 228 229 err = crypto_authenc_genicv(areq, greq->giv, 0); 230 } 231 232 aead_request_complete(areq, err); 233 } 234 235 static int crypto_authenc_givencrypt(struct aead_givcrypt_request *req) 236 { 237 struct crypto_aead *authenc = aead_givcrypt_reqtfm(req); 238 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 239 struct aead_request *areq = &req->areq; 240 struct skcipher_givcrypt_request *greq = aead_request_ctx(areq); 241 u8 *iv = req->giv; 242 int err; 243 244 skcipher_givcrypt_set_tfm(greq, ctx->enc); 245 skcipher_givcrypt_set_callback(greq, aead_request_flags(areq), 246 crypto_authenc_givencrypt_done, areq); 247 skcipher_givcrypt_set_crypt(greq, areq->src, areq->dst, areq->cryptlen, 248 areq->iv); 249 skcipher_givcrypt_set_giv(greq, iv, req->seq); 250 251 err = crypto_skcipher_givencrypt(greq); 252 if (err) 253 return err; 254 255 return crypto_authenc_genicv(areq, iv, CRYPTO_TFM_REQ_MAY_SLEEP); 256 } 257 258 static int crypto_authenc_verify(struct aead_request *req, 259 struct scatterlist *cipher, 260 unsigned int cryptlen) 261 { 262 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 263 u8 *ohash; 264 u8 *ihash; 265 unsigned int authsize; 266 267 ohash = crypto_authenc_hash(req, CRYPTO_TFM_REQ_MAY_SLEEP, cipher, 268 cryptlen); 269 if (IS_ERR(ohash)) 270 return PTR_ERR(ohash); 271 272 authsize = crypto_aead_authsize(authenc); 273 ihash = ohash + authsize; 274 scatterwalk_map_and_copy(ihash, cipher, cryptlen, authsize, 0); 275 return memcmp(ihash, ohash, authsize) ? -EBADMSG: 0; 276 } 277 278 static int crypto_authenc_iverify(struct aead_request *req, u8 *iv, 279 unsigned int cryptlen) 280 { 281 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 282 struct scatterlist *src = req->src; 283 struct scatterlist cipher[2]; 284 struct page *srcp; 285 unsigned int ivsize = crypto_aead_ivsize(authenc); 286 u8 *vsrc; 287 288 srcp = sg_page(src); 289 vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + src->offset; 290 291 if (ivsize) { 292 sg_init_table(cipher, 2); 293 sg_set_buf(cipher, iv, ivsize); 294 authenc_chain(cipher, src, vsrc == iv + ivsize); 295 src = cipher; 296 } 297 298 return crypto_authenc_verify(req, src, cryptlen + ivsize); 299 } 300 301 static int crypto_authenc_decrypt(struct aead_request *req) 302 { 303 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 304 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 305 struct ablkcipher_request *abreq = aead_request_ctx(req); 306 unsigned int cryptlen = req->cryptlen; 307 unsigned int authsize = crypto_aead_authsize(authenc); 308 u8 *iv = req->iv; 309 int err; 310 311 if (cryptlen < authsize) 312 return -EINVAL; 313 cryptlen -= authsize; 314 315 err = crypto_authenc_iverify(req, iv, cryptlen); 316 if (err) 317 return err; 318 319 ablkcipher_request_set_tfm(abreq, ctx->enc); 320 ablkcipher_request_set_callback(abreq, aead_request_flags(req), 321 req->base.complete, req->base.data); 322 ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen, iv); 323 324 return crypto_ablkcipher_decrypt(abreq); 325 } 326 327 static int crypto_authenc_init_tfm(struct crypto_tfm *tfm) 328 { 329 struct crypto_instance *inst = (void *)tfm->__crt_alg; 330 struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst); 331 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); 332 struct crypto_hash *auth; 333 struct crypto_ablkcipher *enc; 334 int err; 335 336 auth = crypto_spawn_hash(&ictx->auth); 337 if (IS_ERR(auth)) 338 return PTR_ERR(auth); 339 340 enc = crypto_spawn_skcipher(&ictx->enc); 341 err = PTR_ERR(enc); 342 if (IS_ERR(enc)) 343 goto err_free_hash; 344 345 ctx->auth = auth; 346 ctx->enc = enc; 347 tfm->crt_aead.reqsize = max_t(unsigned int, 348 (crypto_hash_alignmask(auth) & 349 ~(crypto_tfm_ctx_alignment() - 1)) + 350 crypto_hash_digestsize(auth) * 2, 351 sizeof(struct skcipher_givcrypt_request) + 352 crypto_ablkcipher_reqsize(enc) + 353 crypto_ablkcipher_ivsize(enc)); 354 355 spin_lock_init(&ctx->auth_lock); 356 357 return 0; 358 359 err_free_hash: 360 crypto_free_hash(auth); 361 return err; 362 } 363 364 static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm) 365 { 366 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); 367 368 crypto_free_hash(ctx->auth); 369 crypto_free_ablkcipher(ctx->enc); 370 } 371 372 static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb) 373 { 374 struct crypto_attr_type *algt; 375 struct crypto_instance *inst; 376 struct crypto_alg *auth; 377 struct crypto_alg *enc; 378 struct authenc_instance_ctx *ctx; 379 const char *enc_name; 380 int err; 381 382 algt = crypto_get_attr_type(tb); 383 err = PTR_ERR(algt); 384 if (IS_ERR(algt)) 385 return ERR_PTR(err); 386 387 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 388 return ERR_PTR(-EINVAL); 389 390 auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 391 CRYPTO_ALG_TYPE_HASH_MASK); 392 if (IS_ERR(auth)) 393 return ERR_PTR(PTR_ERR(auth)); 394 395 enc_name = crypto_attr_alg_name(tb[2]); 396 err = PTR_ERR(enc_name); 397 if (IS_ERR(enc_name)) 398 goto out_put_auth; 399 400 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 401 err = -ENOMEM; 402 if (!inst) 403 goto out_put_auth; 404 405 ctx = crypto_instance_ctx(inst); 406 407 err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK); 408 if (err) 409 goto err_free_inst; 410 411 crypto_set_skcipher_spawn(&ctx->enc, inst); 412 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, 413 crypto_requires_sync(algt->type, 414 algt->mask)); 415 if (err) 416 goto err_drop_auth; 417 418 enc = crypto_skcipher_spawn_alg(&ctx->enc); 419 420 err = -ENAMETOOLONG; 421 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, 422 "authenc(%s,%s)", auth->cra_name, enc->cra_name) >= 423 CRYPTO_MAX_ALG_NAME) 424 goto err_drop_enc; 425 426 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, 427 "authenc(%s,%s)", auth->cra_driver_name, 428 enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 429 goto err_drop_enc; 430 431 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; 432 inst->alg.cra_flags |= enc->cra_flags & CRYPTO_ALG_ASYNC; 433 inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority; 434 inst->alg.cra_blocksize = enc->cra_blocksize; 435 inst->alg.cra_alignmask = auth->cra_alignmask | enc->cra_alignmask; 436 inst->alg.cra_type = &crypto_aead_type; 437 438 inst->alg.cra_aead.ivsize = enc->cra_ablkcipher.ivsize; 439 inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ? 440 auth->cra_hash.digestsize : 441 auth->cra_type ? 442 __crypto_shash_alg(auth)->digestsize : 443 auth->cra_digest.dia_digestsize; 444 445 inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx); 446 447 inst->alg.cra_init = crypto_authenc_init_tfm; 448 inst->alg.cra_exit = crypto_authenc_exit_tfm; 449 450 inst->alg.cra_aead.setkey = crypto_authenc_setkey; 451 inst->alg.cra_aead.encrypt = crypto_authenc_encrypt; 452 inst->alg.cra_aead.decrypt = crypto_authenc_decrypt; 453 inst->alg.cra_aead.givencrypt = crypto_authenc_givencrypt; 454 455 out: 456 crypto_mod_put(auth); 457 return inst; 458 459 err_drop_enc: 460 crypto_drop_skcipher(&ctx->enc); 461 err_drop_auth: 462 crypto_drop_spawn(&ctx->auth); 463 err_free_inst: 464 kfree(inst); 465 out_put_auth: 466 inst = ERR_PTR(err); 467 goto out; 468 } 469 470 static void crypto_authenc_free(struct crypto_instance *inst) 471 { 472 struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst); 473 474 crypto_drop_skcipher(&ctx->enc); 475 crypto_drop_spawn(&ctx->auth); 476 kfree(inst); 477 } 478 479 static struct crypto_template crypto_authenc_tmpl = { 480 .name = "authenc", 481 .alloc = crypto_authenc_alloc, 482 .free = crypto_authenc_free, 483 .module = THIS_MODULE, 484 }; 485 486 static int __init crypto_authenc_module_init(void) 487 { 488 return crypto_register_template(&crypto_authenc_tmpl); 489 } 490 491 static void __exit crypto_authenc_module_exit(void) 492 { 493 crypto_unregister_template(&crypto_authenc_tmpl); 494 } 495 496 module_init(crypto_authenc_module_init); 497 module_exit(crypto_authenc_module_exit); 498 499 MODULE_LICENSE("GPL"); 500 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); 501