/* * Authenc: Simple AEAD wrapper for IPsec * * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. * */ #include <crypto/internal/aead.h> #include <crypto/internal/hash.h> #include <crypto/internal/skcipher.h> #include <crypto/authenc.h> #include <crypto/null.h> #include <crypto/scatterwalk.h> #include <linux/err.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/rtnetlink.h> #include <linux/slab.h> #include <linux/spinlock.h> struct authenc_instance_ctx { struct crypto_ahash_spawn auth; struct crypto_skcipher_spawn enc; unsigned int reqoff; }; struct crypto_authenc_ctx { struct crypto_ahash *auth; struct crypto_skcipher *enc; struct crypto_skcipher *null; }; struct authenc_request_ctx { struct scatterlist src[2]; struct scatterlist dst[2]; char tail[]; }; static void authenc_request_complete(struct aead_request *req, int err) { if (err != -EINPROGRESS) aead_request_complete(req, err); } int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key, unsigned int keylen) { struct rtattr *rta = (struct rtattr *)key; struct crypto_authenc_key_param *param; if (!RTA_OK(rta, keylen)) return -EINVAL; if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) return -EINVAL; if (RTA_PAYLOAD(rta) < sizeof(*param)) return -EINVAL; param = RTA_DATA(rta); keys->enckeylen = be32_to_cpu(param->enckeylen); key += RTA_ALIGN(rta->rta_len); keylen -= RTA_ALIGN(rta->rta_len); if (keylen < keys->enckeylen) return -EINVAL; keys->authkeylen = keylen - keys->enckeylen; keys->authkey = key; keys->enckey = key + keys->authkeylen; return 0; } EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, unsigned int keylen) { struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct crypto_ahash *auth = ctx->auth; struct crypto_skcipher *enc = ctx->enc; struct crypto_authenc_keys keys; int err = -EINVAL; if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) goto badkey; crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) & CRYPTO_TFM_REQ_MASK); err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) & CRYPTO_TFM_RES_MASK); if (err) goto out; crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & CRYPTO_TFM_REQ_MASK); err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); crypto_aead_set_flags(authenc, crypto_skcipher_get_flags(enc) & CRYPTO_TFM_RES_MASK); out: return err; badkey: crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); goto out; } static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) { struct aead_request *req = areq->data; struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct aead_instance *inst = aead_alg_instance(authenc); struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); if (err) goto out; scatterwalk_map_and_copy(ahreq->result, req->dst, req->assoclen + req->cryptlen, crypto_aead_authsize(authenc), 1); out: aead_request_complete(req, err); } static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct aead_instance *inst = aead_alg_instance(authenc); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); struct crypto_ahash *auth = ctx->auth; struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); u8 *hash = areq_ctx->tail; int err; hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), crypto_ahash_alignmask(auth) + 1); ahash_request_set_tfm(ahreq, auth); ahash_request_set_crypt(ahreq, req->dst, hash, req->assoclen + req->cryptlen); ahash_request_set_callback(ahreq, flags, authenc_geniv_ahash_done, req); err = crypto_ahash_digest(ahreq); if (err) return err; scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, crypto_aead_authsize(authenc), 1); return 0; } static void crypto_authenc_encrypt_done(struct crypto_async_request *req, int err) { struct aead_request *areq = req->data; if (err) goto out; err = crypto_authenc_genicv(areq, 0); out: authenc_request_complete(areq, err); } static int crypto_authenc_copy_assoc(struct aead_request *req) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); skcipher_request_set_tfm(skreq, ctx->null); skcipher_request_set_callback(skreq, aead_request_flags(req), NULL, NULL); skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, NULL); return crypto_skcipher_encrypt(skreq); } static int crypto_authenc_encrypt(struct aead_request *req) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct aead_instance *inst = aead_alg_instance(authenc); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); struct crypto_skcipher *enc = ctx->enc; unsigned int cryptlen = req->cryptlen; struct skcipher_request *skreq = (void *)(areq_ctx->tail + ictx->reqoff); struct scatterlist *src, *dst; int err; src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); dst = src; if (req->src != req->dst) { err = crypto_authenc_copy_assoc(req); if (err) return err; dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); } skcipher_request_set_tfm(skreq, enc); skcipher_request_set_callback(skreq, aead_request_flags(req), crypto_authenc_encrypt_done, req); skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); err = crypto_skcipher_encrypt(skreq); if (err) return err; return crypto_authenc_genicv(req, aead_request_flags(req)); } static int crypto_authenc_decrypt_tail(struct aead_request *req, unsigned int flags) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct aead_instance *inst = aead_alg_instance(authenc); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); struct skcipher_request *skreq = (void *)(areq_ctx->tail + ictx->reqoff); unsigned int authsize = crypto_aead_authsize(authenc); u8 *ihash = ahreq->result + authsize; struct scatterlist *src, *dst; scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); if (crypto_memneq(ihash, ahreq->result, authsize)) return -EBADMSG; src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); dst = src; if (req->src != req->dst) dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); skcipher_request_set_tfm(skreq, ctx->enc); skcipher_request_set_callback(skreq, aead_request_flags(req), req->base.complete, req->base.data); skcipher_request_set_crypt(skreq, src, dst, req->cryptlen - authsize, req->iv); return crypto_skcipher_decrypt(skreq); } static void authenc_verify_ahash_done(struct crypto_async_request *areq, int err) { struct aead_request *req = areq->data; if (err) goto out; err = crypto_authenc_decrypt_tail(req, 0); out: authenc_request_complete(req, err); } static int crypto_authenc_decrypt(struct aead_request *req) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); unsigned int authsize = crypto_aead_authsize(authenc); struct aead_instance *inst = aead_alg_instance(authenc); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); struct crypto_ahash *auth = ctx->auth; struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); u8 *hash = areq_ctx->tail; int err; hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), crypto_ahash_alignmask(auth) + 1); ahash_request_set_tfm(ahreq, auth); ahash_request_set_crypt(ahreq, req->src, hash, req->assoclen + req->cryptlen - authsize); ahash_request_set_callback(ahreq, aead_request_flags(req), authenc_verify_ahash_done, req); err = crypto_ahash_digest(ahreq); if (err) return err; return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); } static int crypto_authenc_init_tfm(struct crypto_aead *tfm) { struct aead_instance *inst = aead_alg_instance(tfm); struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); struct crypto_ahash *auth; struct crypto_skcipher *enc; struct crypto_skcipher *null; int err; auth = crypto_spawn_ahash(&ictx->auth); if (IS_ERR(auth)) return PTR_ERR(auth); enc = crypto_spawn_skcipher(&ictx->enc); err = PTR_ERR(enc); if (IS_ERR(enc)) goto err_free_ahash; null = crypto_get_default_null_skcipher2(); err = PTR_ERR(null); if (IS_ERR(null)) goto err_free_skcipher; ctx->auth = auth; ctx->enc = enc; ctx->null = null; crypto_aead_set_reqsize( tfm, sizeof(struct authenc_request_ctx) + ictx->reqoff + max_t(unsigned int, crypto_ahash_reqsize(auth) + sizeof(struct ahash_request), sizeof(struct skcipher_request) + crypto_skcipher_reqsize(enc))); return 0; err_free_skcipher: crypto_free_skcipher(enc); err_free_ahash: crypto_free_ahash(auth); return err; } static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) { struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); crypto_free_ahash(ctx->auth); crypto_free_skcipher(ctx->enc); crypto_put_default_null_skcipher2(); } static void crypto_authenc_free(struct aead_instance *inst) { struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); crypto_drop_skcipher(&ctx->enc); crypto_drop_ahash(&ctx->auth); kfree(inst); } static int crypto_authenc_create(struct crypto_template *tmpl, struct rtattr **tb) { struct crypto_attr_type *algt; struct aead_instance *inst; struct hash_alg_common *auth; struct crypto_alg *auth_base; struct skcipher_alg *enc; struct authenc_instance_ctx *ctx; const char *enc_name; int err; algt = crypto_get_attr_type(tb); if (IS_ERR(algt)) return PTR_ERR(algt); if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) return -EINVAL; auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, CRYPTO_ALG_TYPE_AHASH_MASK | crypto_requires_sync(algt->type, algt->mask)); if (IS_ERR(auth)) return PTR_ERR(auth); auth_base = &auth->base; enc_name = crypto_attr_alg_name(tb[2]); err = PTR_ERR(enc_name); if (IS_ERR(enc_name)) goto out_put_auth; inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); err = -ENOMEM; if (!inst) goto out_put_auth; ctx = aead_instance_ctx(inst); err = crypto_init_ahash_spawn(&ctx->auth, auth, aead_crypto_instance(inst)); if (err) goto err_free_inst; crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, crypto_requires_sync(algt->type, algt->mask)); if (err) goto err_drop_auth; enc = crypto_spawn_skcipher_alg(&ctx->enc); ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, auth_base->cra_alignmask + 1); err = -ENAMETOOLONG; if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)", auth_base->cra_name, enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME) goto err_drop_enc; if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)", auth_base->cra_driver_name, enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) goto err_drop_enc; inst->alg.base.cra_flags = (auth_base->cra_flags | enc->base.cra_flags) & CRYPTO_ALG_ASYNC; inst->alg.base.cra_priority = enc->base.cra_priority * 10 + auth_base->cra_priority; inst->alg.base.cra_blocksize = enc->base.cra_blocksize; inst->alg.base.cra_alignmask = auth_base->cra_alignmask | enc->base.cra_alignmask; inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); inst->alg.maxauthsize = auth->digestsize; inst->alg.init = crypto_authenc_init_tfm; inst->alg.exit = crypto_authenc_exit_tfm; inst->alg.setkey = crypto_authenc_setkey; inst->alg.encrypt = crypto_authenc_encrypt; inst->alg.decrypt = crypto_authenc_decrypt; inst->free = crypto_authenc_free; err = aead_register_instance(tmpl, inst); if (err) goto err_drop_enc; out: crypto_mod_put(auth_base); return err; err_drop_enc: crypto_drop_skcipher(&ctx->enc); err_drop_auth: crypto_drop_ahash(&ctx->auth); err_free_inst: kfree(inst); out_put_auth: goto out; } static struct crypto_template crypto_authenc_tmpl = { .name = "authenc", .create = crypto_authenc_create, .module = THIS_MODULE, }; static int __init crypto_authenc_module_init(void) { return crypto_register_template(&crypto_authenc_tmpl); } static void __exit crypto_authenc_module_exit(void) { crypto_unregister_template(&crypto_authenc_tmpl); } module_init(crypto_authenc_module_init); module_exit(crypto_authenc_module_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); MODULE_ALIAS_CRYPTO("authenc");