static PRStatus
rng_init(void)
{
PRUint8 bytes[PRNG_SEEDLEN * 2]; /* entropy + nonce */
unsigned int numBytes;
SECStatus rv = SECSuccess;
if (globalrng == NULL) {
/* bytes needs to have enough space to hold
* a SHA256 hash value. Blow up at compile time if this isn't true */
PR_STATIC_ASSERT(sizeof(bytes) >= SHA256_LENGTH);
/* create a new global RNG context */
globalrng = &theGlobalRng;
PORT_Assert(NULL == globalrng->lock);
/* create a lock for it */
globalrng->lock = PZ_NewLock(nssILockOther);
if (globalrng->lock == NULL) {
globalrng = NULL;
PORT_SetError(PR_OUT_OF_MEMORY_ERROR);
return PR_FAILURE;
}
/* Try to get some seed data for the RNG */
numBytes = (unsigned int)RNG_SystemRNG(bytes, sizeof bytes);
PORT_Assert(numBytes == 0 || numBytes == sizeof bytes);
if (numBytes != 0) {
/* if this is our first call, instantiate, otherwise reseed
* prng_instantiate gets a new clean state, we want to mix
* any previous entropy we may have collected */
if (V(globalrng)[0] == 0) {
rv = prng_instantiate(globalrng, bytes, numBytes);
} else {
rv = prng_reseed_test(globalrng, bytes, numBytes, NULL, 0);
}
memset(bytes, 0, numBytes);
} else {
PZ_DestroyLock(globalrng->lock);
globalrng->lock = NULL;
globalrng = NULL;
return PR_FAILURE;
}
if (rv != SECSuccess) {
return PR_FAILURE;
}
/* the RNG is in a valid state */
globalrng->isValid = PR_TRUE;
globalrng->isKatTest = PR_FALSE;
/* fetch one random value so that we can populate rng->oldV for our
* continous random number test. */
prng_generateNewBytes(globalrng, bytes, SHA256_LENGTH, NULL, 0);
/* Fetch more entropy into the PRNG */
RNG_SystemInfoForRNG();
}
return PR_SUCCESS;
}
/*
* Update the global random number generator with more seeding
* material. Use the Hash_DRBG reseed algorithm from NIST SP-800-90
* section 10.1.1.3
*
* If entropy is NULL, it is fetched from the noise generator.
*/
static SECStatus
prng_reseed(RNGContext *rng, const PRUint8 *entropy, unsigned int entropy_len,
const PRUint8 *additional_input, unsigned int additional_input_len)
{
PRUint8 noiseData[(sizeof rng->V_Data)+PRNG_SEEDLEN];
PRUint8 *noise = &noiseData[0];
/* if entropy wasn't supplied, fetch it. (normal operation case) */
if (entropy == NULL) {
entropy_len = (unsigned int) RNG_SystemRNG(
&noiseData[sizeof rng->V_Data], PRNG_SEEDLEN);
} else {
/* NOTE: this code is only available for testing, not to applications */
/* if entropy was too big for the stack variable, get it from malloc */
if (entropy_len > PRNG_SEEDLEN) {
noise = PORT_Alloc(entropy_len + (sizeof rng->V_Data));
if (noise == NULL) {
return SECFailure;
}
}
PORT_Memcpy(&noise[sizeof rng->V_Data],entropy, entropy_len);
}
if (entropy_len < 256/PR_BITS_PER_BYTE) {
/* noise == &noiseData[0] at this point, so nothing to free */
PORT_SetError(SEC_ERROR_NEED_RANDOM);
return SECFailure;
}
rng->V_type = prngReseedType;
PORT_Memcpy(noise, rng->V_Data, sizeof rng->V_Data);
prng_Hash_df(V(rng), VSize(rng), noise, (sizeof rng->V_Data) + entropy_len,
additional_input, additional_input_len);
/* clear potential CSP */
PORT_Memset(noise, 0, (sizeof rng->V_Data) + entropy_len);
rng->V_type = prngCGenerateType;
prng_Hash_df(rng->C,sizeof rng->C,rng->V_Data,sizeof rng->V_Data,NULL,0);
PRNG_RESET_RESEED_COUNT(rng)
if (noise != &noiseData[0]) {
PORT_Free(noise);
}
return SECSuccess;
}