1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Authenc: Simple AEAD wrapper for IPsec 4 * 5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au> 6 */ 7 8 #include <crypto/internal/aead.h> 9 #include <crypto/internal/hash.h> 10 #include <crypto/internal/skcipher.h> 11 #include <crypto/authenc.h> 12 #include <crypto/null.h> 13 #include <crypto/scatterwalk.h> 14 #include <linux/err.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/rtnetlink.h> 19 #include <linux/slab.h> 20 #include <linux/spinlock.h> 21 22 struct authenc_instance_ctx { 23 struct crypto_ahash_spawn auth; 24 struct crypto_skcipher_spawn enc; 25 unsigned int reqoff; 26 }; 27 28 struct crypto_authenc_ctx { 29 struct crypto_ahash *auth; 30 struct crypto_skcipher *enc; 31 struct crypto_sync_skcipher *null; 32 }; 33 34 struct authenc_request_ctx { 35 struct scatterlist src[2]; 36 struct scatterlist dst[2]; 37 char tail[]; 38 }; 39 40 static void authenc_request_complete(struct aead_request *req, int err) 41 { 42 if (err != -EINPROGRESS) 43 aead_request_complete(req, err); 44 } 45 46 int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key, 47 unsigned int keylen) 48 { 49 struct rtattr *rta = (struct rtattr *)key; 50 struct crypto_authenc_key_param *param; 51 52 if (!RTA_OK(rta, keylen)) 53 return -EINVAL; 54 if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) 55 return -EINVAL; 56 57 /* 58 * RTA_OK() didn't align the rtattr's payload when validating that it 59 * fits in the buffer. Yet, the keys should start on the next 4-byte 60 * aligned boundary. To avoid confusion, require that the rtattr 61 * payload be exactly the param struct, which has a 4-byte aligned size. 62 */ 63 if (RTA_PAYLOAD(rta) != sizeof(*param)) 64 return -EINVAL; 65 BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO); 66 67 param = RTA_DATA(rta); 68 keys->enckeylen = be32_to_cpu(param->enckeylen); 69 70 key += rta->rta_len; 71 keylen -= rta->rta_len; 72 73 if (keylen < keys->enckeylen) 74 return -EINVAL; 75 76 keys->authkeylen = keylen - keys->enckeylen; 77 keys->authkey = key; 78 keys->enckey = key + keys->authkeylen; 79 80 return 0; 81 } 82 EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); 83 84 static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, 85 unsigned int keylen) 86 { 87 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 88 struct crypto_ahash *auth = ctx->auth; 89 struct crypto_skcipher *enc = ctx->enc; 90 struct crypto_authenc_keys keys; 91 int err = -EINVAL; 92 93 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) 94 goto badkey; 95 96 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); 97 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) & 98 CRYPTO_TFM_REQ_MASK); 99 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); 100 crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) & 101 CRYPTO_TFM_RES_MASK); 102 103 if (err) 104 goto out; 105 106 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); 107 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & 108 CRYPTO_TFM_REQ_MASK); 109 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); 110 crypto_aead_set_flags(authenc, crypto_skcipher_get_flags(enc) & 111 CRYPTO_TFM_RES_MASK); 112 113 out: 114 memzero_explicit(&keys, sizeof(keys)); 115 return err; 116 117 badkey: 118 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); 119 goto out; 120 } 121 122 static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) 123 { 124 struct aead_request *req = areq->data; 125 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 126 struct aead_instance *inst = aead_alg_instance(authenc); 127 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 128 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 129 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 130 131 if (err) 132 goto out; 133 134 scatterwalk_map_and_copy(ahreq->result, req->dst, 135 req->assoclen + req->cryptlen, 136 crypto_aead_authsize(authenc), 1); 137 138 out: 139 aead_request_complete(req, err); 140 } 141 142 static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) 143 { 144 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 145 struct aead_instance *inst = aead_alg_instance(authenc); 146 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 147 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 148 struct crypto_ahash *auth = ctx->auth; 149 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 150 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 151 u8 *hash = areq_ctx->tail; 152 int err; 153 154 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 155 crypto_ahash_alignmask(auth) + 1); 156 157 ahash_request_set_tfm(ahreq, auth); 158 ahash_request_set_crypt(ahreq, req->dst, hash, 159 req->assoclen + req->cryptlen); 160 ahash_request_set_callback(ahreq, flags, 161 authenc_geniv_ahash_done, req); 162 163 err = crypto_ahash_digest(ahreq); 164 if (err) 165 return err; 166 167 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, 168 crypto_aead_authsize(authenc), 1); 169 170 return 0; 171 } 172 173 static void crypto_authenc_encrypt_done(struct crypto_async_request *req, 174 int err) 175 { 176 struct aead_request *areq = req->data; 177 178 if (err) 179 goto out; 180 181 err = crypto_authenc_genicv(areq, 0); 182 183 out: 184 authenc_request_complete(areq, err); 185 } 186 187 static int crypto_authenc_copy_assoc(struct aead_request *req) 188 { 189 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 190 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 191 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); 192 193 skcipher_request_set_sync_tfm(skreq, ctx->null); 194 skcipher_request_set_callback(skreq, aead_request_flags(req), 195 NULL, NULL); 196 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, 197 NULL); 198 199 return crypto_skcipher_encrypt(skreq); 200 } 201 202 static int crypto_authenc_encrypt(struct aead_request *req) 203 { 204 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 205 struct aead_instance *inst = aead_alg_instance(authenc); 206 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 207 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 208 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 209 struct crypto_skcipher *enc = ctx->enc; 210 unsigned int cryptlen = req->cryptlen; 211 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 212 ictx->reqoff); 213 struct scatterlist *src, *dst; 214 int err; 215 216 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 217 dst = src; 218 219 if (req->src != req->dst) { 220 err = crypto_authenc_copy_assoc(req); 221 if (err) 222 return err; 223 224 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 225 } 226 227 skcipher_request_set_tfm(skreq, enc); 228 skcipher_request_set_callback(skreq, aead_request_flags(req), 229 crypto_authenc_encrypt_done, req); 230 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); 231 232 err = crypto_skcipher_encrypt(skreq); 233 if (err) 234 return err; 235 236 return crypto_authenc_genicv(req, aead_request_flags(req)); 237 } 238 239 static int crypto_authenc_decrypt_tail(struct aead_request *req, 240 unsigned int flags) 241 { 242 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 243 struct aead_instance *inst = aead_alg_instance(authenc); 244 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 245 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 246 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 247 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 248 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 249 ictx->reqoff); 250 unsigned int authsize = crypto_aead_authsize(authenc); 251 u8 *ihash = ahreq->result + authsize; 252 struct scatterlist *src, *dst; 253 254 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); 255 256 if (crypto_memneq(ihash, ahreq->result, authsize)) 257 return -EBADMSG; 258 259 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 260 dst = src; 261 262 if (req->src != req->dst) 263 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 264 265 skcipher_request_set_tfm(skreq, ctx->enc); 266 skcipher_request_set_callback(skreq, aead_request_flags(req), 267 req->base.complete, req->base.data); 268 skcipher_request_set_crypt(skreq, src, dst, 269 req->cryptlen - authsize, req->iv); 270 271 return crypto_skcipher_decrypt(skreq); 272 } 273 274 static void authenc_verify_ahash_done(struct crypto_async_request *areq, 275 int err) 276 { 277 struct aead_request *req = areq->data; 278 279 if (err) 280 goto out; 281 282 err = crypto_authenc_decrypt_tail(req, 0); 283 284 out: 285 authenc_request_complete(req, err); 286 } 287 288 static int crypto_authenc_decrypt(struct aead_request *req) 289 { 290 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 291 unsigned int authsize = crypto_aead_authsize(authenc); 292 struct aead_instance *inst = aead_alg_instance(authenc); 293 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 294 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 295 struct crypto_ahash *auth = ctx->auth; 296 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 297 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 298 u8 *hash = areq_ctx->tail; 299 int err; 300 301 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 302 crypto_ahash_alignmask(auth) + 1); 303 304 ahash_request_set_tfm(ahreq, auth); 305 ahash_request_set_crypt(ahreq, req->src, hash, 306 req->assoclen + req->cryptlen - authsize); 307 ahash_request_set_callback(ahreq, aead_request_flags(req), 308 authenc_verify_ahash_done, req); 309 310 err = crypto_ahash_digest(ahreq); 311 if (err) 312 return err; 313 314 return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); 315 } 316 317 static int crypto_authenc_init_tfm(struct crypto_aead *tfm) 318 { 319 struct aead_instance *inst = aead_alg_instance(tfm); 320 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 321 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 322 struct crypto_ahash *auth; 323 struct crypto_skcipher *enc; 324 struct crypto_sync_skcipher *null; 325 int err; 326 327 auth = crypto_spawn_ahash(&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_ahash; 335 336 null = crypto_get_default_null_skcipher(); 337 err = PTR_ERR(null); 338 if (IS_ERR(null)) 339 goto err_free_skcipher; 340 341 ctx->auth = auth; 342 ctx->enc = enc; 343 ctx->null = null; 344 345 crypto_aead_set_reqsize( 346 tfm, 347 sizeof(struct authenc_request_ctx) + 348 ictx->reqoff + 349 max_t(unsigned int, 350 crypto_ahash_reqsize(auth) + 351 sizeof(struct ahash_request), 352 sizeof(struct skcipher_request) + 353 crypto_skcipher_reqsize(enc))); 354 355 return 0; 356 357 err_free_skcipher: 358 crypto_free_skcipher(enc); 359 err_free_ahash: 360 crypto_free_ahash(auth); 361 return err; 362 } 363 364 static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) 365 { 366 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 367 368 crypto_free_ahash(ctx->auth); 369 crypto_free_skcipher(ctx->enc); 370 crypto_put_default_null_skcipher(); 371 } 372 373 static void crypto_authenc_free(struct aead_instance *inst) 374 { 375 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); 376 377 crypto_drop_skcipher(&ctx->enc); 378 crypto_drop_ahash(&ctx->auth); 379 kfree(inst); 380 } 381 382 static int crypto_authenc_create(struct crypto_template *tmpl, 383 struct rtattr **tb) 384 { 385 struct crypto_attr_type *algt; 386 struct aead_instance *inst; 387 struct hash_alg_common *auth; 388 struct crypto_alg *auth_base; 389 struct skcipher_alg *enc; 390 struct authenc_instance_ctx *ctx; 391 const char *enc_name; 392 int err; 393 394 algt = crypto_get_attr_type(tb); 395 if (IS_ERR(algt)) 396 return PTR_ERR(algt); 397 398 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 399 return -EINVAL; 400 401 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, 402 CRYPTO_ALG_TYPE_AHASH_MASK | 403 crypto_requires_sync(algt->type, algt->mask)); 404 if (IS_ERR(auth)) 405 return PTR_ERR(auth); 406 407 auth_base = &auth->base; 408 409 enc_name = crypto_attr_alg_name(tb[2]); 410 err = PTR_ERR(enc_name); 411 if (IS_ERR(enc_name)) 412 goto out_put_auth; 413 414 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 415 err = -ENOMEM; 416 if (!inst) 417 goto out_put_auth; 418 419 ctx = aead_instance_ctx(inst); 420 421 err = crypto_init_ahash_spawn(&ctx->auth, auth, 422 aead_crypto_instance(inst)); 423 if (err) 424 goto err_free_inst; 425 426 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); 427 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, 428 crypto_requires_sync(algt->type, 429 algt->mask)); 430 if (err) 431 goto err_drop_auth; 432 433 enc = crypto_spawn_skcipher_alg(&ctx->enc); 434 435 ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, 436 auth_base->cra_alignmask + 1); 437 438 err = -ENAMETOOLONG; 439 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 440 "authenc(%s,%s)", auth_base->cra_name, 441 enc->base.cra_name) >= 442 CRYPTO_MAX_ALG_NAME) 443 goto err_drop_enc; 444 445 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 446 "authenc(%s,%s)", auth_base->cra_driver_name, 447 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 448 goto err_drop_enc; 449 450 inst->alg.base.cra_flags = (auth_base->cra_flags | 451 enc->base.cra_flags) & CRYPTO_ALG_ASYNC; 452 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 453 auth_base->cra_priority; 454 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 455 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 456 enc->base.cra_alignmask; 457 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); 458 459 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); 460 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); 461 inst->alg.maxauthsize = auth->digestsize; 462 463 inst->alg.init = crypto_authenc_init_tfm; 464 inst->alg.exit = crypto_authenc_exit_tfm; 465 466 inst->alg.setkey = crypto_authenc_setkey; 467 inst->alg.encrypt = crypto_authenc_encrypt; 468 inst->alg.decrypt = crypto_authenc_decrypt; 469 470 inst->free = crypto_authenc_free; 471 472 err = aead_register_instance(tmpl, inst); 473 if (err) 474 goto err_drop_enc; 475 476 out: 477 crypto_mod_put(auth_base); 478 return err; 479 480 err_drop_enc: 481 crypto_drop_skcipher(&ctx->enc); 482 err_drop_auth: 483 crypto_drop_ahash(&ctx->auth); 484 err_free_inst: 485 kfree(inst); 486 out_put_auth: 487 goto out; 488 } 489 490 static struct crypto_template crypto_authenc_tmpl = { 491 .name = "authenc", 492 .create = crypto_authenc_create, 493 .module = THIS_MODULE, 494 }; 495 496 static int __init crypto_authenc_module_init(void) 497 { 498 return crypto_register_template(&crypto_authenc_tmpl); 499 } 500 501 static void __exit crypto_authenc_module_exit(void) 502 { 503 crypto_unregister_template(&crypto_authenc_tmpl); 504 } 505 506 subsys_initcall(crypto_authenc_module_init); 507 module_exit(crypto_authenc_module_exit); 508 509 MODULE_LICENSE("GPL"); 510 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); 511 MODULE_ALIAS_CRYPTO("authenc"); 512