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