460 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Authenc: Simple AEAD wrapper for IPsec4 *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 it59 * fits in the buffer. Yet, the keys should start on the next 4-byte60 * aligned boundary. To avoid confusion, require that the rtattr61 * 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