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 22struct authenc_instance_ctx { 23 struct crypto_ahash_spawn auth; 24 struct crypto_skcipher_spawn enc; 25 unsigned int reqoff; 26}; 27 28struct crypto_authenc_ctx { 29 struct crypto_ahash *auth; 30 struct crypto_skcipher *enc; 31 struct crypto_sync_skcipher *null; 32}; 33 34struct authenc_request_ctx { 35 struct scatterlist src[2]; 36 struct scatterlist dst[2]; 37 char tail[]; 38}; 39 40static void authenc_request_complete(struct aead_request *req, int err) 41{ 42 if (err != -EINPROGRESS) 43 aead_request_complete(req, err); 44} 45 46int 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} 82EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); 83 84static 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 out; 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 if (err) 101 goto out; 102 103 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); 104 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & 105 CRYPTO_TFM_REQ_MASK); 106 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); 107out: 108 memzero_explicit(&keys, sizeof(keys)); 109 return err; 110} 111 112static void authenc_geniv_ahash_done(void *data, int err) 113{ 114 struct aead_request *req = data; 115 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 116 struct aead_instance *inst = aead_alg_instance(authenc); 117 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 118 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 119 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 120 121 if (err) 122 goto out; 123 124 scatterwalk_map_and_copy(ahreq->result, req->dst, 125 req->assoclen + req->cryptlen, 126 crypto_aead_authsize(authenc), 1); 127 128out: 129 aead_request_complete(req, err); 130} 131 132static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) 133{ 134 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 135 struct aead_instance *inst = aead_alg_instance(authenc); 136 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 137 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 138 struct crypto_ahash *auth = ctx->auth; 139 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 140 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 141 u8 *hash = areq_ctx->tail; 142 int err; 143 144 ahash_request_set_tfm(ahreq, auth); 145 ahash_request_set_crypt(ahreq, req->dst, hash, 146 req->assoclen + req->cryptlen); 147 ahash_request_set_callback(ahreq, flags, 148 authenc_geniv_ahash_done, req); 149 150 err = crypto_ahash_digest(ahreq); 151 if (err) 152 return err; 153 154 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, 155 crypto_aead_authsize(authenc), 1); 156 157 return 0; 158} 159 160static void crypto_authenc_encrypt_done(void *data, int err) 161{ 162 struct aead_request *areq = data; 163 164 if (err) 165 goto out; 166 167 err = crypto_authenc_genicv(areq, 0); 168 169out: 170 authenc_request_complete(areq, err); 171} 172 173static int crypto_authenc_copy_assoc(struct aead_request *req) 174{ 175 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 176 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 177 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); 178 179 skcipher_request_set_sync_tfm(skreq, ctx->null); 180 skcipher_request_set_callback(skreq, aead_request_flags(req), 181 NULL, NULL); 182 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, 183 NULL); 184 185 return crypto_skcipher_encrypt(skreq); 186} 187 188static int crypto_authenc_encrypt(struct aead_request *req) 189{ 190 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 191 struct aead_instance *inst = aead_alg_instance(authenc); 192 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 193 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 194 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 195 struct crypto_skcipher *enc = ctx->enc; 196 unsigned int cryptlen = req->cryptlen; 197 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 198 ictx->reqoff); 199 struct scatterlist *src, *dst; 200 int err; 201 202 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 203 dst = src; 204 205 if (req->src != req->dst) { 206 err = crypto_authenc_copy_assoc(req); 207 if (err) 208 return err; 209 210 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 211 } 212 213 skcipher_request_set_tfm(skreq, enc); 214 skcipher_request_set_callback(skreq, aead_request_flags(req), 215 crypto_authenc_encrypt_done, req); 216 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); 217 218 err = crypto_skcipher_encrypt(skreq); 219 if (err) 220 return err; 221 222 return crypto_authenc_genicv(req, aead_request_flags(req)); 223} 224 225static int crypto_authenc_decrypt_tail(struct aead_request *req, 226 unsigned int flags) 227{ 228 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 229 struct aead_instance *inst = aead_alg_instance(authenc); 230 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 231 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 232 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 233 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 234 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 235 ictx->reqoff); 236 unsigned int authsize = crypto_aead_authsize(authenc); 237 u8 *ihash = ahreq->result + authsize; 238 struct scatterlist *src, *dst; 239 240 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); 241 242 if (crypto_memneq(ihash, ahreq->result, authsize)) 243 return -EBADMSG; 244 245 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 246 dst = src; 247 248 if (req->src != req->dst) 249 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 250 251 skcipher_request_set_tfm(skreq, ctx->enc); 252 skcipher_request_set_callback(skreq, flags, 253 req->base.complete, req->base.data); 254 skcipher_request_set_crypt(skreq, src, dst, 255 req->cryptlen - authsize, req->iv); 256 257 return crypto_skcipher_decrypt(skreq); 258} 259 260static void authenc_verify_ahash_done(void *data, int err) 261{ 262 struct aead_request *req = data; 263 264 if (err) 265 goto out; 266 267 err = crypto_authenc_decrypt_tail(req, 0); 268 269out: 270 authenc_request_complete(req, err); 271} 272 273static int crypto_authenc_decrypt(struct aead_request *req) 274{ 275 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 276 unsigned int authsize = crypto_aead_authsize(authenc); 277 struct aead_instance *inst = aead_alg_instance(authenc); 278 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 279 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 280 struct crypto_ahash *auth = ctx->auth; 281 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 282 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 283 u8 *hash = areq_ctx->tail; 284 int err; 285 286 ahash_request_set_tfm(ahreq, auth); 287 ahash_request_set_crypt(ahreq, req->src, hash, 288 req->assoclen + req->cryptlen - authsize); 289 ahash_request_set_callback(ahreq, aead_request_flags(req), 290 authenc_verify_ahash_done, req); 291 292 err = crypto_ahash_digest(ahreq); 293 if (err) 294 return err; 295 296 return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); 297} 298 299static int crypto_authenc_init_tfm(struct crypto_aead *tfm) 300{ 301 struct aead_instance *inst = aead_alg_instance(tfm); 302 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 303 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 304 struct crypto_ahash *auth; 305 struct crypto_skcipher *enc; 306 struct crypto_sync_skcipher *null; 307 int err; 308 309 auth = crypto_spawn_ahash(&ictx->auth); 310 if (IS_ERR(auth)) 311 return PTR_ERR(auth); 312 313 enc = crypto_spawn_skcipher(&ictx->enc); 314 err = PTR_ERR(enc); 315 if (IS_ERR(enc)) 316 goto err_free_ahash; 317 318 null = crypto_get_default_null_skcipher(); 319 err = PTR_ERR(null); 320 if (IS_ERR(null)) 321 goto err_free_skcipher; 322 323 ctx->auth = auth; 324 ctx->enc = enc; 325 ctx->null = null; 326 327 crypto_aead_set_reqsize( 328 tfm, 329 sizeof(struct authenc_request_ctx) + 330 ictx->reqoff + 331 max_t(unsigned int, 332 crypto_ahash_reqsize(auth) + 333 sizeof(struct ahash_request), 334 sizeof(struct skcipher_request) + 335 crypto_skcipher_reqsize(enc))); 336 337 return 0; 338 339err_free_skcipher: 340 crypto_free_skcipher(enc); 341err_free_ahash: 342 crypto_free_ahash(auth); 343 return err; 344} 345 346static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) 347{ 348 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 349 350 crypto_free_ahash(ctx->auth); 351 crypto_free_skcipher(ctx->enc); 352 crypto_put_default_null_skcipher(); 353} 354 355static void crypto_authenc_free(struct aead_instance *inst) 356{ 357 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); 358 359 crypto_drop_skcipher(&ctx->enc); 360 crypto_drop_ahash(&ctx->auth); 361 kfree(inst); 362} 363 364static int crypto_authenc_create(struct crypto_template *tmpl, 365 struct rtattr **tb) 366{ 367 u32 mask; 368 struct aead_instance *inst; 369 struct authenc_instance_ctx *ctx; 370 struct skcipher_alg_common *enc; 371 struct hash_alg_common *auth; 372 struct crypto_alg *auth_base; 373 int err; 374 375 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask); 376 if (err) 377 return err; 378 379 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 380 if (!inst) 381 return -ENOMEM; 382 ctx = aead_instance_ctx(inst); 383 384 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst), 385 crypto_attr_alg_name(tb[1]), 0, mask); 386 if (err) 387 goto err_free_inst; 388 auth = crypto_spawn_ahash_alg(&ctx->auth); 389 auth_base = &auth->base; 390 391 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst), 392 crypto_attr_alg_name(tb[2]), 0, mask); 393 if (err) 394 goto err_free_inst; 395 enc = crypto_spawn_skcipher_alg_common(&ctx->enc); 396 397 ctx->reqoff = 2 * auth->digestsize; 398 399 err = -ENAMETOOLONG; 400 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 401 "authenc(%s,%s)", auth_base->cra_name, 402 enc->base.cra_name) >= 403 CRYPTO_MAX_ALG_NAME) 404 goto err_free_inst; 405 406 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 407 "authenc(%s,%s)", auth_base->cra_driver_name, 408 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 409 goto err_free_inst; 410 411 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 412 auth_base->cra_priority; 413 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 414 inst->alg.base.cra_alignmask = enc->base.cra_alignmask; 415 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); 416 417 inst->alg.ivsize = enc->ivsize; 418 inst->alg.chunksize = enc->chunksize; 419 inst->alg.maxauthsize = auth->digestsize; 420 421 inst->alg.init = crypto_authenc_init_tfm; 422 inst->alg.exit = crypto_authenc_exit_tfm; 423 424 inst->alg.setkey = crypto_authenc_setkey; 425 inst->alg.encrypt = crypto_authenc_encrypt; 426 inst->alg.decrypt = crypto_authenc_decrypt; 427 428 inst->free = crypto_authenc_free; 429 430 err = aead_register_instance(tmpl, inst); 431 if (err) { 432err_free_inst: 433 crypto_authenc_free(inst); 434 } 435 return err; 436} 437 438static struct crypto_template crypto_authenc_tmpl = { 439 .name = "authenc", 440 .create = crypto_authenc_create, 441 .module = THIS_MODULE, 442}; 443 444static int __init crypto_authenc_module_init(void) 445{ 446 return crypto_register_template(&crypto_authenc_tmpl); 447} 448 449static void __exit crypto_authenc_module_exit(void) 450{ 451 crypto_unregister_template(&crypto_authenc_tmpl); 452} 453 454subsys_initcall(crypto_authenc_module_init); 455module_exit(crypto_authenc_module_exit); 456 457MODULE_LICENSE("GPL"); 458MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); 459MODULE_ALIAS_CRYPTO("authenc"); 460