168 lines
3.4 KiB
C
168 lines
3.4 KiB
C
/*
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* Copyright (C) 2020 Tobias Brunner
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*
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* Copyright (C) secunet Security Networks AG
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <openssl/evp.h>
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/* SHA3 was added with 1.1.1 */
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#if OPENSSL_VERSION_NUMBER >= 0x1010100fL && !defined(OPENSSL_NO_SHAKE)
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#include "openssl_xof.h"
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#define KECCAK_STATE_SIZE 200 /* 1600 bits*/
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typedef struct private_xof_t private_xof_t;
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/**
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* Private data
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*/
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struct private_xof_t {
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/**
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* Public interface.
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*/
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xof_t public;
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/**
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* XOF algorithm to be used
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*/
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ext_out_function_t algorithm;
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/**
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* Internal type reference
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*/
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const EVP_MD *md;
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/**
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* Internal context
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*/
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EVP_MD_CTX *ctx;
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/**
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* Current seed
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*/
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chunk_t seed;
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/**
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* Offset into generated data
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*/
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size_t offset;
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};
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METHOD(xof_t, get_type, ext_out_function_t,
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private_xof_t *this)
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{
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return this->algorithm;
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}
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METHOD(xof_t, get_bytes, bool,
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private_xof_t *this, size_t out_len, uint8_t *buffer)
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{
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bool success = FALSE;
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chunk_t data;
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/* we can call EVP_DigestFinalXOF() only once, so to support an arbitrary
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* number of calls to get_bytes(), we request all the data we already
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* requested previously and just ignore what we already handed out */
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if (EVP_DigestInit_ex(this->ctx, this->md, NULL) == 1 &&
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EVP_DigestUpdate(this->ctx, this->seed.ptr, this->seed.len) == 1)
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{
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data = chunk_alloc(out_len + this->offset);
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if (EVP_DigestFinalXOF(this->ctx, data.ptr, data.len) == 1)
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{
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memcpy(buffer, data.ptr + this->offset, out_len);
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this->offset += out_len;
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success = TRUE;
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}
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chunk_clear(&data);
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}
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return success;
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}
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METHOD(xof_t, allocate_bytes, bool,
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private_xof_t *this, size_t out_len, chunk_t *chunk)
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{
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*chunk = chunk_alloc(out_len);
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return get_bytes(this, out_len, chunk->ptr);
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}
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METHOD(xof_t, get_block_size, size_t,
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private_xof_t *this)
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{
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return EVP_MD_block_size(this->md);
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}
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METHOD(xof_t, get_seed_size, size_t,
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private_xof_t *this)
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{
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return KECCAK_STATE_SIZE - EVP_MD_block_size(this->md);
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}
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METHOD(xof_t, set_seed, bool,
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private_xof_t *this, chunk_t seed)
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{
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chunk_clear(&this->seed);
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this->seed = chunk_clone(seed);
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this->offset = 0;
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return TRUE;
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}
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METHOD(xof_t, destroy, void,
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private_xof_t *this)
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{
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EVP_MD_CTX_free(this->ctx);
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chunk_clear(&this->seed);
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free(this);
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}
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/*
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* Described in header
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*/
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xof_t *openssl_xof_create(ext_out_function_t algorithm)
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{
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private_xof_t *this;
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const EVP_MD *md;
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switch (algorithm)
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{
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case XOF_SHAKE_128:
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md = EVP_shake128();
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break;
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case XOF_SHAKE_256:
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md = EVP_shake256();
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break;
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default:
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return NULL;
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}
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INIT(this,
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.public = {
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.get_type = _get_type,
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.get_bytes = _get_bytes,
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.allocate_bytes = _allocate_bytes,
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.get_block_size = _get_block_size,
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.get_seed_size = _get_seed_size,
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.set_seed = _set_seed,
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.destroy = _destroy,
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},
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.algorithm = algorithm,
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.md = md,
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.ctx = EVP_MD_CTX_new(),
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);
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return &this->public;
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}
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#endif /* OPENSSL_NO_ECDH */
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