lc_chacha20_drng.h

Go to the documentation of this file.

/*
 * Copyright (C) 2016 - 2024, Stephan Mueller <smueller@chronox.de>
 *
 * License: see COPYING 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_CHACHA20_DRNG_H
#define _LC_CHACHA20_DRNG_H
 
#include "ext_headers.h"
#include "lc_chacha20.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct lc_chacha20_drng_ctx {
        struct lc_sym_ctx cc20;
};
 
#define LC_CC20_DRNG_STATE_SIZE (LC_SYM_STATE_SIZE(lc_chacha20))
#define LC_CC20_DRNG_CTX_SIZE                                                  \
        (LC_CC20_DRNG_STATE_SIZE + sizeof(struct lc_chacha20_drng_ctx))
 
#define _LC_CC20_DRNG_SET_CTX(name, ctx, offset)                               \
        _LC_SYM_SET_CTX((&name->cc20), lc_chacha20, ctx, offset)
 
#define LC_CC20_DRNG_SET_CTX(name)                                             \
        _LC_CC20_DRNG_SET_CTX(name, name, sizeof(struct lc_chacha20_drng_ctx))
 
static inline void lc_cc20_drng_zero(struct lc_chacha20_drng_ctx *cc20_ctx)
{
        struct lc_sym_ctx *sym_ctx = &cc20_ctx->cc20;
 
        lc_memset_secure((uint8_t *)cc20_ctx +
                                 sizeof(struct lc_chacha20_drng_ctx),
                         0, LC_CC20_DRNG_STATE_SIZE);
        lc_sym_init(sym_ctx);
}
 
#define LC_CC20_DRNG_CTX_ON_STACK(name)                                             \
        _Pragma("GCC diagnostic push")                                              \
                _Pragma("GCC diagnostic ignored \"-Wvla\"") _Pragma(                \
                        "GCC diagnostic ignored \"-Wdeclaration-after-statement\"") \
                        LC_ALIGNED_SYM_BUFFER(name##_ctx_buf, lc_chacha20,          \
                                              LC_CC20_DRNG_CTX_SIZE);               \
        struct lc_chacha20_drng_ctx *name =                                         \
                (struct lc_chacha20_drng_ctx *)name##_ctx_buf;                      \
        LC_CC20_DRNG_SET_CTX(name);                                                 \
        lc_cc20_drng_zero(name);                                                    \
        _Pragma("GCC diagnostic pop")
 
int lc_cc20_drng_alloc(struct lc_chacha20_drng_ctx **cc20_ctx);
 
void lc_cc20_drng_zero_free(struct lc_chacha20_drng_ctx *cc20_ctx);
 
void lc_cc20_drng_generate(struct lc_chacha20_drng_ctx *cc20_ctx,
                           uint8_t *outbuf, size_t outbuflen);
 
void lc_cc20_drng_seed(struct lc_chacha20_drng_ctx *cc20_ctx,
                       const uint8_t *inbuf, size_t inbuflen);
 
#ifdef __cplusplus
}
#endif
 
#endif /* _LC_CHACHA20_DRNG_H */