From: Tadeusz Struk Subject: [PATCH 1/3] crypto: authenc - add TLS type encryption Date: Sat, 05 Mar 2016 17:20:49 -0800 Message-ID: <20160306012049.6369.99836.stgit@tstruk-mobl1> References: <20160306012044.6369.63924.stgit@tstruk-mobl1> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net, tadeusz.struk@intel.com To: herbert@gondor.apana.org.au Return-path: Received: from mga09.intel.com ([134.134.136.24]:63617 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751081AbcCFBZW (ORCPT ); Sat, 5 Mar 2016 20:25:22 -0500 In-Reply-To: <20160306012044.6369.63924.stgit@tstruk-mobl1> Sender: linux-crypto-owner@vger.kernel.org List-ID: This patch adds a new authentication mode for TLS type encryption. During encrypt it generates auth data + padding and then the plaintext || authdata || padding is encrypted. This requires the user to provide extra space for the cipher text. The required space can be calculated as outlen = assoc len + plaintext len + hash size + cipher block size On decrypt first the whole buffer is decrypted, and then verification of the authdata and padding is performed. Signed-off-by: Tadeusz Struk --- crypto/Makefile | 2 crypto/encauth.c | 510 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 511 insertions(+), 1 deletion(-) create mode 100644 crypto/encauth.c diff --git a/crypto/Makefile b/crypto/Makefile index 4f4ef7e..a372335 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -103,7 +103,7 @@ obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o obj-$(CONFIG_CRYPTO_CRC32C) += crc32c_generic.o obj-$(CONFIG_CRYPTO_CRC32) += crc32_generic.o obj-$(CONFIG_CRYPTO_CRCT10DIF) += crct10dif_common.o crct10dif_generic.o -obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o +obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o encauth.o obj-$(CONFIG_CRYPTO_LZO) += lzo.o obj-$(CONFIG_CRYPTO_LZ4) += lz4.o obj-$(CONFIG_CRYPTO_LZ4HC) += lz4hc.o diff --git a/crypto/encauth.c b/crypto/encauth.c new file mode 100644 index 0000000..3c0ee1a --- /dev/null +++ b/crypto/encauth.c @@ -0,0 +1,510 @@ +/* + * Encauth: Simple AEAD wrapper for TLS. + * Derived from authenc.c + * + * Copyright (c) 2016 Intel Corp. + * + * Author: Tadeusz Struk + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct encauth_instance_ctx { + struct crypto_ahash_spawn auth; + struct crypto_skcipher_spawn enc; + unsigned int reqoff; +}; + +struct crypto_encauth_ctx { + struct crypto_ahash *auth; + struct crypto_ablkcipher *enc; + struct crypto_blkcipher *null; +}; + +struct encauth_request_ctx { + struct scatterlist src[2]; + struct scatterlist dst[2]; + int padd_err; + u8 paddlen; + char tail[]; +}; + +static void encauth_request_complete(struct aead_request *req, int err) +{ + if (err != -EINPROGRESS) + aead_request_complete(req, err); +} + +static int crypto_encauth_setkey(struct crypto_aead *encauth, const u8 *key, + unsigned int keylen) +{ + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(encauth); + struct crypto_ahash *auth = ctx->auth; + struct crypto_ablkcipher *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(encauth) & + CRYPTO_TFM_REQ_MASK); + err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); + crypto_aead_set_flags(encauth, crypto_ahash_get_flags(auth) & + CRYPTO_TFM_RES_MASK); + + if (err) + goto out; + + crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); + crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(encauth) & + CRYPTO_TFM_REQ_MASK); + err = crypto_ablkcipher_setkey(enc, keys.enckey, keys.enckeylen); + crypto_aead_set_flags(encauth, crypto_ablkcipher_get_flags(enc) & + CRYPTO_TFM_RES_MASK); + +out: + return err; + +badkey: + crypto_aead_set_flags(encauth, CRYPTO_TFM_RES_BAD_KEY_LEN); + goto out; +} + +static int crypto_encauth_copy_assoc(struct aead_request *req) +{ + struct crypto_aead *encauth = crypto_aead_reqtfm(req); + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(encauth); + struct blkcipher_desc desc = { + .tfm = ctx->null, + }; + + return crypto_blkcipher_encrypt(&desc, req->dst, req->src, + req->assoclen); +} + +static void encauth_encrypt_done(struct crypto_async_request *req, int err) +{ + struct aead_request *areq = req->data; + + encauth_request_complete(areq, err); +} + +static int crypto_encauth_encrypt(struct aead_request *req) +{ + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(tfm); + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(tfm); + struct encauth_instance_ctx *ictx = aead_instance_ctx(inst); + struct encauth_request_ctx *areq_ctx = aead_request_ctx(req); + struct crypto_ablkcipher *enc = ctx->enc; + struct ablkcipher_request *abreq = (void *)(areq_ctx->tail + + ictx->reqoff); + struct scatterlist *src, *dst; + int err; + + sg_init_table(areq_ctx->src, 2); + src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); + dst = src; + + if (req->src != req->dst) { + err = crypto_encauth_copy_assoc(req); + if (err) + return err; + + sg_init_table(areq_ctx->dst, 2); + dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); + } + ablkcipher_request_set_tfm(abreq, enc); + ablkcipher_request_set_callback(abreq, aead_request_flags(req), + encauth_encrypt_done, req); + ablkcipher_request_set_crypt(abreq, src, dst, req->cryptlen + + crypto_aead_authsize(tfm) + + areq_ctx->paddlen, req->iv); + return crypto_ablkcipher_encrypt(abreq); +} + +static void encauth_geniv_ahash_done(struct crypto_async_request *areq, int err) +{ + struct aead_request *req = areq->data; + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(tfm); + struct encauth_instance_ctx *ictx = aead_instance_ctx(inst); + struct encauth_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(tfm), 1); + err = crypto_encauth_encrypt(req); +out: + encauth_request_complete(req, err); +} + +static int crypto_encauth_genicv_encrypt(struct aead_request *req) +{ + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(tfm); + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(tfm); + struct encauth_instance_ctx *ictx = aead_instance_ctx(inst); + struct crypto_ahash *auth = ctx->auth; + struct encauth_request_ctx *areq_ctx = aead_request_ctx(req); + struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); + u8 paddlen, *hash = areq_ctx->tail; + const unsigned int bs = crypto_aead_blocksize(tfm); + unsigned int as = crypto_aead_authsize(tfm); + u8 padd[bs]; + int err; + + hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), + crypto_ahash_alignmask(auth) + 1); + + /* apply padding */ + paddlen = bs - ((req->cryptlen + as) % bs); + memset(padd, paddlen - 1, paddlen); + if (sg_copy_buffer(req->src, sg_nents(req->src), padd, paddlen, + req->cryptlen + req->assoclen + as, 0) != paddlen) + return -EINVAL; + + areq_ctx->paddlen = paddlen; + ahash_request_set_tfm(ahreq, auth); + ahash_request_set_crypt(ahreq, req->src, hash, + req->assoclen + req->cryptlen); + ahash_request_set_callback(ahreq, aead_request_flags(req), + encauth_geniv_ahash_done, req); + err = crypto_ahash_digest(ahreq); + if (err) + return err; + + scatterwalk_map_and_copy(hash, req->src, req->assoclen + req->cryptlen, + crypto_aead_authsize(tfm), 1); + return crypto_encauth_encrypt(req); +} + +static void encauth_dgst_verify_done(struct crypto_async_request *req, int err) +{ + struct aead_request *areq = req->data; + struct crypto_aead *tfm = crypto_aead_reqtfm(areq); + unsigned int authsize = crypto_aead_authsize(tfm); + struct ahash_request *ahreq = (void *)req; + struct encauth_request_ctx *areq_ctx = aead_request_ctx(areq); + u8 *ihash = ahreq->result + authsize; + + scatterwalk_map_and_copy(ihash, areq->dst, ahreq->nbytes, authsize, 0); + + if (crypto_memneq(ihash, ahreq->result, authsize) || areq_ctx->padd_err) + err = -EBADMSG; + + encauth_request_complete(areq, err); +} + +static int crypto_encauth_dgst_verify(struct aead_request *req, + unsigned int flags) +{ + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + unsigned int authsize = crypto_aead_authsize(tfm); + struct aead_instance *inst = aead_alg_instance(tfm); + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(tfm); + struct encauth_instance_ctx *ictx = aead_instance_ctx(inst); + struct crypto_ahash *auth = ctx->auth; + struct encauth_request_ctx *areq_ctx = aead_request_ctx(req); + struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); + u8 *hash = areq_ctx->tail; + int i, err = 0, padd_err = 0; + u8 paddlen, *ihash; + u8 padd[255]; + + scatterwalk_map_and_copy(&paddlen, req->dst, req->assoclen + + req->cryptlen - 1, 1, 0); + + if (paddlen > 255 || paddlen > req->cryptlen) { + paddlen = 1; + padd_err = -EBADMSG; + } + + scatterwalk_map_and_copy(padd, req->dst, req->assoclen + + req->cryptlen - paddlen, paddlen, 0); + + for (i = 0; i < paddlen; i++) { + if (padd[i] != paddlen) + padd_err = -EBADMSG; + } + + areq_ctx->padd_err = padd_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 - + authsize - paddlen - 1); + ahash_request_set_callback(ahreq, aead_request_flags(req), + encauth_dgst_verify_done, req); + err = crypto_ahash_digest(ahreq); + if (err) + return err; + + ihash = ahreq->result + authsize; + scatterwalk_map_and_copy(ihash, req->dst, ahreq->nbytes, authsize, 0); + if (crypto_memneq(ihash, ahreq->result, authsize) || padd_err) + err = -EBADMSG; + + return err; +} + +static void encauth_decrypt_done(struct crypto_async_request *areq, int err) +{ + struct aead_request *req = areq->data; + + if (err) + goto out; + + err = crypto_encauth_dgst_verify(req, aead_request_flags(req)); +out: + encauth_request_complete(req, err); +} + +static int crypto_encauth_decrypt(struct aead_request *req) +{ + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(tfm); + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(tfm); + struct encauth_instance_ctx *ictx = aead_instance_ctx(inst); + struct encauth_request_ctx *areq_ctx = aead_request_ctx(req); + struct ablkcipher_request *abreq = (void *)(areq_ctx->tail + + ictx->reqoff); + struct scatterlist *src, *dst; + int err; + + sg_init_table(areq_ctx->src, 2); + src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); + dst = src; + + if (req->src != req->dst) { + err = crypto_encauth_copy_assoc(req); + if (err) + return err; + + sg_init_table(areq_ctx->dst, 2); + dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); + } + ablkcipher_request_set_tfm(abreq, ctx->enc); + ablkcipher_request_set_callback(abreq, aead_request_flags(req), + encauth_decrypt_done, req); + ablkcipher_request_set_crypt(abreq, src, dst, req->cryptlen, req->iv); + err = crypto_ablkcipher_decrypt(abreq); + if (err) + return err; + + return crypto_encauth_dgst_verify(req, aead_request_flags(req)); +} + +static int crypto_encauth_init_tfm(struct crypto_aead *tfm) +{ + struct aead_instance *inst = aead_alg_instance(tfm); + struct encauth_instance_ctx *ictx = aead_instance_ctx(inst); + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(tfm); + struct crypto_ahash *auth; + struct crypto_ablkcipher *enc; + struct crypto_blkcipher *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_skcipher(); + 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 encauth_request_ctx) + + ictx->reqoff + + max_t(unsigned int, crypto_ahash_reqsize(auth) + + sizeof(struct ahash_request), + sizeof(struct ablkcipher_request) + + crypto_ablkcipher_reqsize(enc))); + return 0; + +err_free_skcipher: + crypto_free_ablkcipher(enc); +err_free_ahash: + crypto_free_ahash(auth); + return err; +} + +static void crypto_encauth_exit_tfm(struct crypto_aead *tfm) +{ + struct crypto_encauth_ctx *ctx = crypto_aead_ctx(tfm); + + crypto_free_ahash(ctx->auth); + crypto_free_ablkcipher(ctx->enc); + crypto_put_default_null_skcipher(); +} + +static void crypto_encauth_free(struct aead_instance *inst) +{ + struct encauth_instance_ctx *ctx = aead_instance_ctx(inst); + + crypto_drop_skcipher(&ctx->enc); + crypto_drop_ahash(&ctx->auth); + kfree(inst); +} + +static int crypto_encauth_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 crypto_alg *enc; + struct encauth_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); + 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_skcipher_spawn_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, + "encauth(%s,%s)", auth_base->cra_name, enc->cra_name) >= + CRYPTO_MAX_ALG_NAME) + goto err_drop_enc; + + if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, + "encauth(%s,%s)", auth_base->cra_driver_name, + enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) + goto err_drop_enc; + + inst->alg.base.cra_flags = enc->cra_flags & CRYPTO_ALG_ASYNC; + inst->alg.base.cra_priority = enc->cra_priority * 10 + + auth_base->cra_priority; + inst->alg.base.cra_blocksize = enc->cra_blocksize; + inst->alg.base.cra_alignmask = auth_base->cra_alignmask | + enc->cra_alignmask; + inst->alg.base.cra_ctxsize = sizeof(struct crypto_encauth_ctx); + + inst->alg.ivsize = enc->cra_ablkcipher.ivsize; + inst->alg.maxauthsize = auth->digestsize; + + inst->alg.init = crypto_encauth_init_tfm; + inst->alg.exit = crypto_encauth_exit_tfm; + + inst->alg.setkey = crypto_encauth_setkey; + inst->alg.encrypt = crypto_encauth_genicv_encrypt; + inst->alg.decrypt = crypto_encauth_decrypt; + + inst->free = crypto_encauth_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_encauth_tmpl = { + .name = "encauth", + .create = crypto_encauth_create, + .module = THIS_MODULE, +}; + +static int __init crypto_encauth_module_init(void) +{ + return crypto_register_template(&crypto_encauth_tmpl); +} + +static void __exit crypto_encauth_module_exit(void) +{ + crypto_unregister_template(&crypto_encauth_tmpl); +} + +module_init(crypto_encauth_module_init); +module_exit(crypto_encauth_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Simple AEAD wrapper for TLS"); +MODULE_ALIAS_CRYPTO("encauth");