toxcore/toxencryptsave/crypto_pwhash_scryptsalsa208sha256/utils.c

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef  VANILLA_NACL /* toxcore only uses this when libsodium is unavailable */

#ifndef __STDC_WANT_LIB_EXT1__
# define __STDC_WANT_LIB_EXT1__ 1
#endif
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <signal.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
#endif

#include "utils.h"

#ifdef _WIN32
# include <windows.h>
# include <wincrypt.h>
#else
# include <unistd.h>
#endif

#ifdef HAVE_WEAK_SYMBOLS
__attribute__((weak)) void
__sodium_dummy_symbol_to_prevent_lto(void * const pnt, const size_t len)
{
    (void) pnt;
    (void) len;
}
#endif

void
sodium_memzero(void * const pnt, const size_t len)
{
#ifdef _WIN32
    SecureZeroMemory(pnt, len);
#elif defined(HAVE_MEMSET_S)
    if (memset_s(pnt, (rsize_t) len, 0, (rsize_t) len) != 0) {
        abort();
    }
#elif defined(HAVE_EXPLICIT_BZERO)
    explicit_bzero(pnt, len);
#elif HAVE_WEAK_SYMBOLS
    memset(pnt, 0, len);
    __sodium_dummy_symbol_to_prevent_lto(pnt, len);
#else
    volatile unsigned char *pnt_ = (volatile unsigned char *) pnt;
    size_t                     i = (size_t) 0U;

    while (i < len) {
        pnt_[i++] = 0U;
    }
#endif
}

int
sodium_memcmp(const void * const b1_, const void * const b2_, size_t len)
{
    const unsigned char *b1 = (const unsigned char *) b1_;
    const unsigned char *b2 = (const unsigned char *) b2_;
    size_t               i;
    unsigned char        d = (unsigned char) 0U;

    for (i = 0U; i < len; i++) {
        d |= b1[i] ^ b2[i];
    }
    return (int) ((1 & ((d - 1) >> 8)) - 1);
}

#endif