int
rand_bytes (uint8_t *output, int len)
{
static int gather_delay = 0;
ctr_drbg_context *rng_ctx = rand_ctx_get();
while (len > 0)
{
const size_t blen = min_int (len, CTR_DRBG_MAX_REQUEST);
if (0 != ctr_drbg_random(rng_ctx, output, blen))
return 0;
output += blen;
len -= blen;
if (gather_delay++ >= FOX_ENTROPY_GATHER_FREQUENCY)
{
entropy_context *e_ctx = rng_ctx->p_entropy;
ASSERT(e_ctx != NULL);
if (0 != entropy_gather(e_ctx))
return 0;
gather_delay = 0;
}
}
return 1;
}
void rand_ctx_init_platform_entropy(int min_size, bool use_urandom)
{
static bool platform_set = false;
if (!platform_set)
{
ctr_drbg_context *cd_ctx = rand_ctx_get();
entropy_context *ec = cd_ctx->p_entropy;
f_source_ptr f_source = platform_entropy_poll;
ASSERT(NULL != ec);
#ifndef WIN32
if (use_urandom)
f_source = urandom_entropy_poll;
#endif
if (0 != entropy_add_source(ec, f_source, NULL, min_size))
msg (M_FATAL, "Failed to add platform source to entropy pool");
if (!rand_ctx_reseed())
msg (M_FATAL, "ERROR: Random number generator failed to obtain entropy to reseed");
platform_set = true;
}
}
void
rand_ctx_enable_prediction_resistance()
{
mbedtls_ctr_drbg_context *cd_ctx = rand_ctx_get();
mbedtls_ctr_drbg_set_prediction_resistance(cd_ctx, 1);
}
int rand_ctx_reseed()
{
ctr_drbg_context *cd_ctx = rand_ctx_get();
entropy_context *ec = cd_ctx->p_entropy;
ASSERT(NULL != ec);
if (!entropy_gather_blocking(ec))
return 0;
if (0 != ctr_drbg_reseed(cd_ctx, NULL, 0))
return 0;
return 1;
}
int
rand_bytes (uint8_t *output, int len)
{
ctr_drbg_context *rng_ctx = rand_ctx_get();
while (len > 0)
{
const size_t blen = min_int (len, CTR_DRBG_MAX_REQUEST);
if (0 != ctr_drbg_random(rng_ctx, output, blen))
return 0;
output += blen;
len -= blen;
}
return 1;
}
