lc_kdf_ctr.h

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/*
 * Copyright (C) 2022 - 2024, Stephan Mueller <smueller@chronox.de>
 *
 * License: see LICENSE file in root directory
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
 
#ifndef LC_KDF_CTR_H
#define LC_KDF_CTR_H
 
#include "ext_headers.h"
#include "lc_hash.h"
#include "lc_rng.h"
#include "lc_hmac.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
int lc_kdf_ctr_init(struct lc_hmac_ctx *hmac_ctx, const uint8_t *key,
                    size_t keylen);
 
int lc_kdf_ctr_generate(struct lc_hmac_ctx *hmac_ctx, const uint8_t *label,
                        size_t labellen, uint8_t *dst, size_t dlen);
 
int lc_kdf_ctr(const struct lc_hash *hash, const uint8_t *key, size_t keylen,
               const uint8_t *label, size_t labellen, uint8_t *dst,
               size_t dlen);
 
/***************************** Counter KDF as RNG *****************************/
 
struct lc_kdf_ctr_ctx {
        uint32_t counter;
        uint8_t rng_initialized : 1;
        struct lc_hmac_ctx hmac_ctx;
};
 
#define LC_CTR_KDF_STATE_SIZE(hashname) (LC_HMAC_CTX_SIZE(hashname))
#define LC_CTR_KDF_CTX_SIZE(hashname)                                          \
        (sizeof(struct lc_kdf_ctr_ctx) + LC_CTR_KDF_STATE_SIZE(hashname))
 
#define _LC_CTR_KDF_SET_CTX(name, hashname, ctx, offset)                       \
        _LC_HMAC_SET_CTX((&(name)->hmac_ctx), hashname, ctx, offset)
 
#define LC_CTR_KDF_SET_CTX(name, hashname)                                     \
        _LC_CTR_KDF_SET_CTX(name, hashname, name, sizeof(struct lc_kdf_ctr_ctx))
 
/* CTR_KDF DRNG implementation */
extern const struct lc_rng *lc_kdf_ctr_rng;
 
#define LC_CTR_KDF_DRNG_CTX_SIZE(hashname)                                     \
        (sizeof(struct lc_rng_ctx) + LC_CTR_KDF_CTX_SIZE(hashname))
 
#define LC_CTR_KDF_DRNG_SET_CTX(name, hashname)                                \
        LC_CTR_KDF_SET_CTX(name, hashname)
 
#define LC_CTR_KDF_RNG_CTX(name, hashname)                                     \
        LC_RNG_CTX(name, lc_kdf_ctr_rng);                                      \
        LC_CTR_KDF_DRNG_SET_CTX(((struct lc_kdf_ctr_ctx *)(name->rng_state)),  \
                                hashname);                                     \
        lc_rng_zero(name)
 
#define LC_CTR_KDF_DRNG_CTX_ON_STACK(name, hashname)                                \
        _Pragma("GCC diagnostic push")                                              \
                _Pragma("GCC diagnostic ignored \"-Wvla\"") _Pragma(                \
                        "GCC diagnostic ignored \"-Wdeclaration-after-statement\"") \
                        LC_ALIGNED_BUFFER(name##_ctx_buf,                           \
                                          LC_CTR_KDF_DRNG_CTX_SIZE(hashname),       \
                                          LC_HASH_COMMON_ALIGNMENT);                \
        struct lc_rng_ctx *name = (struct lc_rng_ctx *)name##_ctx_buf;              \
        LC_CTR_KDF_RNG_CTX(name, hashname);                                         \
        _Pragma("GCC diagnostic pop")
 
int lc_kdf_ctr_rng_alloc(struct lc_rng_ctx **state, const struct lc_hash *hash);
 
#ifdef __cplusplus
}
#endif
 
#endif /* LC_KDF_CTR_H */