/*
* Generate some output and apply a statistical RNG test to it.
*/
static void
cprng_strong_rngtest(struct cprng_strong *cprng)
{
KASSERT(mutex_owned(&cprng->cs_lock));
/* XXX Switch to a pool cache instead? */
rngtest_t *const rt = kmem_intr_alloc(sizeof(*rt), KM_NOSLEEP);
if (rt == NULL)
/* XXX Warn? */
return;
(void)strlcpy(rt->rt_name, cprng->cs_name, sizeof(rt->rt_name));
if (nist_ctr_drbg_generate(&cprng->cs_drbg, rt->rt_b, sizeof(rt->rt_b),
NULL, 0))
panic("cprng %s: NIST CTR_DRBG failed after reseed",
cprng->cs_name);
if (rngtest(rt)) {
printf("cprng %s: failed statistical RNG test\n",
cprng->cs_name);
/* XXX Not clear that this does any good... */
cprng->cs_ready = false;
rndsink_schedule(cprng->cs_rndsink);
}
explicit_memset(rt, 0, sizeof(*rt)); /* paranoia */
kmem_intr_free(rt, sizeof(*rt));
}
/*
* Generate some data from the underlying generator.
*/
static void
cprng_strong_generate(struct cprng_strong *cprng, void *buffer, size_t bytes)
{
const uint32_t cc = cprng_counter();
KASSERT(bytes <= CPRNG_MAX_LEN);
KASSERT(mutex_owned(&cprng->cs_lock));
/*
* Generate some data from the NIST CTR_DRBG. Caller
* guarantees reseed if we're not ready, and if we exhaust the
* generator, we mark ourselves not ready. Consequently, this
* call to the CTR_DRBG should not fail.
*/
if (__predict_false(nist_ctr_drbg_generate(&cprng->cs_drbg, buffer,
bytes, &cc, sizeof(cc))))
panic("cprng %s: NIST CTR_DRBG failed", cprng->cs_name);
/*
* If we've been seeing a lot of use, ask for some fresh
* entropy soon.
*/
if (__predict_false(nist_ctr_drbg_reseed_advised_p(&cprng->cs_drbg)))
rndsink_schedule(cprng->cs_rndsink);
/*
* If we just exhausted the generator, inform the next user
* that we need a reseed.
*/
if (__predict_false(nist_ctr_drbg_reseed_needed_p(&cprng->cs_drbg))) {
cprng->cs_ready = false;
rndsink_schedule(cprng->cs_rndsink); /* paranoia */
}
}
uint8_t ntru_rand_default_generate(uint8_t rand_data[], uint16_t len, NtruRandContext *rand_ctx) {
nist_ctr_drbg_generate(rand_ctx->state, rand_data, len, NULL, 0);
return 1;
}