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 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 145 crypto_ahash_alignmask(auth) + 1); 146 147 ahash_request_set_tfm(ahreq, auth); 148 ahash_request_set_crypt(ahreq, req->dst, hash, 149 req->assoclen + req->cryptlen); 150 ahash_request_set_callback(ahreq, flags, 151 authenc_geniv_ahash_done, req); 152 153 err = crypto_ahash_digest(ahreq); 154 if (err) 155 return err; 156 157 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, 158 crypto_aead_authsize(authenc), 1); 159 160 return 0; 161} 162 163static void crypto_authenc_encrypt_done(void *data, int err) 164{ 165 struct aead_request *areq = data; 166 167 if (err) 168 goto out; 169 170 err = crypto_authenc_genicv(areq, 0); 171 172out: 173 authenc_request_complete(areq, err); 174} 175 176static int crypto_authenc_copy_assoc(struct aead_request *req) 177{ 178 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 179 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 180 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); 181 182 skcipher_request_set_sync_tfm(skreq, ctx->null); 183 skcipher_request_set_callback(skreq, aead_request_flags(req), 184 NULL, NULL); 185 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, 186 NULL); 187 188 return crypto_skcipher_encrypt(skreq); 189} 190 191static int crypto_authenc_encrypt(struct aead_request *req) 192{ 193 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 194 struct aead_instance *inst = aead_alg_instance(authenc); 195 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 196 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 197 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 198 struct crypto_skcipher *enc = ctx->enc; 199 unsigned int cryptlen = req->cryptlen; 200 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 201 ictx->reqoff); 202 struct scatterlist *src, *dst; 203 int err; 204 205 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 206 dst = src; 207 208 if (req->src != req->dst) { 209 err = crypto_authenc_copy_assoc(req); 210 if (err) 211 return err; 212 213 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 214 } 215 216 skcipher_request_set_tfm(skreq, enc); 217 skcipher_request_set_callback(skreq, aead_request_flags(req), 218 crypto_authenc_encrypt_done, req); 219 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); 220 221 err = crypto_skcipher_encrypt(skreq); 222 if (err) 223 return err; 224 225 return crypto_authenc_genicv(req, aead_request_flags(req)); 226} 227 228static int crypto_authenc_decrypt_tail(struct aead_request *req, 229 unsigned int flags) 230{ 231 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 232 struct aead_instance *inst = aead_alg_instance(authenc); 233 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 234 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 235 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 236 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 237 struct skcipher_request *skreq = (void *)(areq_ctx->tail + 238 ictx->reqoff); 239 unsigned int authsize = crypto_aead_authsize(authenc); 240 u8 *ihash = ahreq->result + authsize; 241 struct scatterlist *src, *dst; 242 243 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); 244 245 if (crypto_memneq(ihash, ahreq->result, authsize)) 246 return -EBADMSG; 247 248 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); 249 dst = src; 250 251 if (req->src != req->dst) 252 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); 253 254 skcipher_request_set_tfm(skreq, ctx->enc); 255 skcipher_request_set_callback(skreq, flags, 256 req->base.complete, req->base.data); 257 skcipher_request_set_crypt(skreq, src, dst, 258 req->cryptlen - authsize, req->iv); 259 260 return crypto_skcipher_decrypt(skreq); 261} 262 263static void authenc_verify_ahash_done(void *data, int err) 264{ 265 struct aead_request *req = data; 266 267 if (err) 268 goto out; 269 270 err = crypto_authenc_decrypt_tail(req, 0); 271 272out: 273 authenc_request_complete(req, err); 274} 275 276static int crypto_authenc_decrypt(struct aead_request *req) 277{ 278 struct crypto_aead *authenc = crypto_aead_reqtfm(req); 279 unsigned int authsize = crypto_aead_authsize(authenc); 280 struct aead_instance *inst = aead_alg_instance(authenc); 281 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); 282 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 283 struct crypto_ahash *auth = ctx->auth; 284 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); 285 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); 286 u8 *hash = areq_ctx->tail; 287 int err; 288 289 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), 290 crypto_ahash_alignmask(auth) + 1); 291 292 ahash_request_set_tfm(ahreq, auth); 293 ahash_request_set_crypt(ahreq, req->src, hash, 294 req->assoclen + req->cryptlen - authsize); 295 ahash_request_set_callback(ahreq, aead_request_flags(req), 296 authenc_verify_ahash_done, req); 297 298 err = crypto_ahash_digest(ahreq); 299 if (err) 300 return err; 301 302 return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); 303} 304 305static int crypto_authenc_init_tfm(struct crypto_aead *tfm) 306{ 307 struct aead_instance *inst = aead_alg_instance(tfm); 308 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); 309 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 310 struct crypto_ahash *auth; 311 struct crypto_skcipher *enc; 312 struct crypto_sync_skcipher *null; 313 int err; 314 315 auth = crypto_spawn_ahash(&ictx->auth); 316 if (IS_ERR(auth)) 317 return PTR_ERR(auth); 318 319 enc = crypto_spawn_skcipher(&ictx->enc); 320 err = PTR_ERR(enc); 321 if (IS_ERR(enc)) 322 goto err_free_ahash; 323 324 null = crypto_get_default_null_skcipher(); 325 err = PTR_ERR(null); 326 if (IS_ERR(null)) 327 goto err_free_skcipher; 328 329 ctx->auth = auth; 330 ctx->enc = enc; 331 ctx->null = null; 332 333 crypto_aead_set_reqsize( 334 tfm, 335 sizeof(struct authenc_request_ctx) + 336 ictx->reqoff + 337 max_t(unsigned int, 338 crypto_ahash_reqsize(auth) + 339 sizeof(struct ahash_request), 340 sizeof(struct skcipher_request) + 341 crypto_skcipher_reqsize(enc))); 342 343 return 0; 344 345err_free_skcipher: 346 crypto_free_skcipher(enc); 347err_free_ahash: 348 crypto_free_ahash(auth); 349 return err; 350} 351 352static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) 353{ 354 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); 355 356 crypto_free_ahash(ctx->auth); 357 crypto_free_skcipher(ctx->enc); 358 crypto_put_default_null_skcipher(); 359} 360 361static void crypto_authenc_free(struct aead_instance *inst) 362{ 363 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); 364 365 crypto_drop_skcipher(&ctx->enc); 366 crypto_drop_ahash(&ctx->auth); 367 kfree(inst); 368} 369 370static int crypto_authenc_create(struct crypto_template *tmpl, 371 struct rtattr **tb) 372{ 373 u32 mask; 374 struct aead_instance *inst; 375 struct authenc_instance_ctx *ctx; 376 struct hash_alg_common *auth; 377 struct crypto_alg *auth_base; 378 struct skcipher_alg *enc; 379 int err; 380 381 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask); 382 if (err) 383 return err; 384 385 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); 386 if (!inst) 387 return -ENOMEM; 388 ctx = aead_instance_ctx(inst); 389 390 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst), 391 crypto_attr_alg_name(tb[1]), 0, mask); 392 if (err) 393 goto err_free_inst; 394 auth = crypto_spawn_ahash_alg(&ctx->auth); 395 auth_base = &auth->base; 396 397 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst), 398 crypto_attr_alg_name(tb[2]), 0, mask); 399 if (err) 400 goto err_free_inst; 401 enc = crypto_spawn_skcipher_alg(&ctx->enc); 402 403 ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, 404 auth_base->cra_alignmask + 1); 405 406 err = -ENAMETOOLONG; 407 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, 408 "authenc(%s,%s)", auth_base->cra_name, 409 enc->base.cra_name) >= 410 CRYPTO_MAX_ALG_NAME) 411 goto err_free_inst; 412 413 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, 414 "authenc(%s,%s)", auth_base->cra_driver_name, 415 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 416 goto err_free_inst; 417 418 inst->alg.base.cra_priority = enc->base.cra_priority * 10 + 419 auth_base->cra_priority; 420 inst->alg.base.cra_blocksize = enc->base.cra_blocksize; 421 inst->alg.base.cra_alignmask = auth_base->cra_alignmask | 422 enc->base.cra_alignmask; 423 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); 424 425 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); 426 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); 427 inst->alg.maxauthsize = auth->digestsize; 428 429 inst->alg.init = crypto_authenc_init_tfm; 430 inst->alg.exit = crypto_authenc_exit_tfm; 431 432 inst->alg.setkey = crypto_authenc_setkey; 433 inst->alg.encrypt = crypto_authenc_encrypt; 434 inst->alg.decrypt = crypto_authenc_decrypt; 435 436 inst->free = crypto_authenc_free; 437 438 err = aead_register_instance(tmpl, inst); 439 if (err) { 440err_free_inst: 441 crypto_authenc_free(inst); 442 } 443 return err; 444} 445 446static struct crypto_template crypto_authenc_tmpl = { 447 .name = "authenc", 448 .create = crypto_authenc_create, 449 .module = THIS_MODULE, 450}; 451 452static int __init crypto_authenc_module_init(void) 453{ 454 return crypto_register_template(&crypto_authenc_tmpl); 455} 456 457static void __exit crypto_authenc_module_exit(void) 458{ 459 crypto_unregister_template(&crypto_authenc_tmpl); 460} 461 462subsys_initcall(crypto_authenc_module_init); 463module_exit(crypto_authenc_module_exit); 464 465MODULE_LICENSE("GPL"); 466MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); 467MODULE_ALIAS_CRYPTO("authenc"); 468