| 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 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); |
| 107 | out: |
| 108 | memzero_explicit(&keys, sizeof(keys)); |
| 109 | return err; |
| 110 | } |
| 111 | |
| 112 | static 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 | |
| 128 | out: |
| 129 | aead_request_complete(req, err); |
| 130 | } |
| 131 | |
| 132 | static 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 | |
| 160 | static 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 | |
| 169 | out: |
| 170 | authenc_request_complete(areq, err); |
| 171 | } |
| 172 | |
| 173 | static 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 | |
| 188 | static 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 | |
| 225 | static 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 | |
| 260 | static 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 | |
| 269 | out: |
| 270 | authenc_request_complete(req, err); |
| 271 | } |
| 272 | |
| 273 | static 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 | |
| 299 | static 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 | |
| 339 | err_free_skcipher: |
| 340 | crypto_free_skcipher(enc); |
| 341 | err_free_ahash: |
| 342 | crypto_free_ahash(auth); |
| 343 | return err; |
| 344 | } |
| 345 | |
| 346 | static 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 | |
| 355 | static 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 | |
| 364 | static 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) { |
| 432 | err_free_inst: |
| 433 | crypto_authenc_free(inst); |
| 434 | } |
| 435 | return err; |
| 436 | } |
| 437 | |
| 438 | static struct crypto_template crypto_authenc_tmpl = { |
| 439 | .name = "authenc", |
| 440 | .create = crypto_authenc_create, |
| 441 | .module = THIS_MODULE, |
| 442 | }; |
| 443 | |
| 444 | static int __init crypto_authenc_module_init(void) |
| 445 | { |
| 446 | return crypto_register_template(&crypto_authenc_tmpl); |
| 447 | } |
| 448 | |
| 449 | static void __exit crypto_authenc_module_exit(void) |
| 450 | { |
| 451 | crypto_unregister_template(&crypto_authenc_tmpl); |
| 452 | } |
| 453 | |
| 454 | subsys_initcall(crypto_authenc_module_init); |
| 455 | module_exit(crypto_authenc_module_exit); |
| 456 | |
| 457 | MODULE_LICENSE("GPL"); |
| 458 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); |
| 459 | MODULE_ALIAS_CRYPTO("authenc"); |