lcx_rng.h

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/*******************************************************************************
 *   Ledger Nano S - Secure firmware
 *   (c) 2022 Ledger
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 ********************************************************************************/
 
#ifndef LCX_RNG_H
#define LCX_RNG_H
 
#include "lcx_wrappers.h"
#include "lcx_hash.h"
#include "libcxng.h"
 
#ifdef HAVE_RNG_RFC6979
#define CX_RFC6979_BUFFER_LENGTH 64
#define CX_RFC6979_MAX_RLEN      66
 
typedef struct {
    uint8_t  v[CX_RFC6979_BUFFER_LENGTH + 1];
    uint8_t  k[CX_RFC6979_BUFFER_LENGTH];
    uint8_t  q[CX_RFC6979_MAX_RLEN];
    uint32_t q_len;
    uint32_t r_len;
    uint8_t  tmp[CX_RFC6979_MAX_RLEN];
    cx_md_t  hash_id;
    size_t   md_len;
 
    union {
#if (!defined(HAVE_SHA512) && !defined(HAVE_SHA384) && !defined(HAVE_SHA256) \
     && !defined(HAVE_SHA224))                                               \
    || !defined(HAVE_HMAC)
#error No hmac defined for rfc6979 support
#endif
 
        cx_hmac_t hmac;
 
#if defined(HAVE_SHA512) || defined(HAVE_SHA384)
        cx_hmac_sha512_t hmac_sha512;
#endif
 
#if defined(HAVE_SHA256) || defined(HAVE_SHA224)
        cx_hmac_sha256_t hmac_sha256;
#endif
    };
} cx_rnd_rfc6979_ctx_t;
#endif  // HAVE_RNG_RFC6979
 
#ifdef HAVE_RNG
void cx_rng_no_throw(uint8_t *buffer, size_t len);
 
static inline unsigned char *cx_rng(uint8_t *buffer, size_t len)
{
    cx_rng_no_throw(buffer, len);
    return buffer;
}
 
static inline uint32_t cx_rng_u32(void)
{
    uint32_t r;
    cx_rng_no_throw((uint8_t *) &r, sizeof(uint32_t));
    return r;
}
 
static inline uint8_t cx_rng_u8(void)
{
    uint8_t r;
    cx_rng_no_throw((uint8_t *) &r, sizeof(uint8_t));
    return r;
}
 
typedef uint32_t (*cx_rng_u32_range_randfunc_t)(void);
 
uint32_t cx_rng_u32_range_func(uint32_t a, uint32_t b, cx_rng_u32_range_randfunc_t randfunc);
 
static inline uint32_t cx_rng_u32_range(uint32_t a, uint32_t b)
{
    return cx_rng_u32_range_func(a, b, cx_rng_u32);
}
 
WARN_UNUSED_RESULT cx_err_t cx_rng_rfc6979(cx_md_t        hash_id,
                                           const uint8_t *x,
                                           size_t         x_len,
                                           const uint8_t *h1,
                                           size_t         h1_len,
                                           const uint8_t *q,
                                           size_t         q_len,
                                           uint8_t       *out,
                                           size_t         out_len);
#endif  // HAVE_RNG
 
#ifdef HAVE_RNG_RFC6979
WARN_UNUSED_RESULT cx_err_t cx_rng_rfc6979_init(cx_rnd_rfc6979_ctx_t *rfc_ctx,
                                                cx_md_t               hash_id,
                                                const uint8_t        *x,
                                                size_t                x_len,
                                                const uint8_t        *h1,
                                                size_t                h1_len,
                                                const uint8_t        *q,
                                                size_t                q_len);
 
WARN_UNUSED_RESULT cx_err_t cx_rng_rfc6979_next(cx_rnd_rfc6979_ctx_t *rfc_ctx,
                                                uint8_t              *out,
                                                size_t                out_len);
#endif  // HAVE_RNG_RFC6979
 
#endif  // LCX_RNG_H