/* os_get_random - Get cryptographically strong pseudo random data :
* Buffer for pseudo random data :
* Length of the buffer Returns:
* 0 on success, -1 on failure */
int ICACHE_FLASH_ATTR os_get_random(unsigned char * buf, size_t len)
{
if(buf != NULL) {
while(len) {
uint32 z = phy_get_rand();
do {
*buf++ = (char)z;
z >>= 8;
} while(--len & 3);
}
}
return 0;
}
/**
* Set a series of bytes with a random number. Individual bytes can be 0
*/
EXP_FUNC void STDCALL get_random(int num_rand_bytes, uint8_t *rand_data)
{
#if !defined(WIN32) && defined(CONFIG_USE_DEV_URANDOM)
/* use the Linux default */
read(rng_fd, rand_data, num_rand_bytes); /* read from /dev/urandom */
#elif defined(WIN32) && defined(CONFIG_WIN32_USE_CRYPTO_LIB)
/* use Microsoft Crypto Libraries */
CryptGenRandom(gCryptProv, num_rand_bytes, rand_data);
#elif defined(ESP8266)
for (size_t cb = 0; cb < num_rand_bytes; cb += 4) {
uint32_t r = phy_get_rand();
size_t left = num_rand_bytes - cb;
left = (left < 4) ? left : 4;
memcpy(rand_data + cb, &r, left);
}
#else /* nothing else to use, so use a custom RNG */
/* The method we use when we've got nothing better. Use RC4, time
and a couple of random seeds to generate a random sequence */
RC4_CTX rng_ctx;
struct timeval tv;
MD5_CTX rng_digest_ctx;
uint8_t digest[MD5_SIZE];
uint64_t *ep;
int i;
/* A proper implementation would use counters etc for entropy */
gettimeofday(&tv, NULL);
ep = (uint64_t *)entropy_pool;
ep[0] ^= ENTROPY_COUNTER1;
ep[1] ^= ENTROPY_COUNTER2;
/* use a digested version of the entropy pool as a key */
MD5_Init(&rng_digest_ctx);
MD5_Update(&rng_digest_ctx, entropy_pool, ENTROPY_POOL_SIZE);
MD5_Final(digest, &rng_digest_ctx);
/* come up with the random sequence */
RC4_setup(&rng_ctx, digest, MD5_SIZE); /* use as a key */
memcpy(rand_data, entropy_pool, num_rand_bytes < ENTROPY_POOL_SIZE ?
num_rand_bytes : ENTROPY_POOL_SIZE);
RC4_crypt(&rng_ctx, rand_data, rand_data, num_rand_bytes);
/* move things along */
for (i = ENTROPY_POOL_SIZE-1; i >= MD5_SIZE ; i--)
entropy_pool[i] = entropy_pool[i-MD5_SIZE];
/* insert the digest at the start of the entropy pool */
memcpy(entropy_pool, digest, MD5_SIZE);
#endif
}
// Restores settings to default. Prevents accidental calling
//usage: First call with no parameter, then call with returned code
// resetSystemSettings(resetSystemSettings());
uint32_t resetSystemSettings(uint32_t code/* = 0*/)
{
static uint32_t challenge=0;
const char* naStr = "na";
if(code == 0)
{
challenge = phy_get_rand();
}
else if(code == challenge)
{
if(FIRMWARE_VER_MAJOR == 1)
{
if(FIRMWARE_VER_MINOR == 0) /* for 01.00 */
{
gSysCfg.fwVerMinor = FIRMWARE_VER_MINOR;
gSysCfg.fwVerMajor = FIRMWARE_VER_MAJOR;
gSysCfg.wifiStationIsConfigured = 0;
if(gSysCfg.wifiSSID)
free(gSysCfg.wifiSSID);
gSysCfg.wifiSSID = new char[sizeof(naStr)+1];
memcpy(gSysCfg.wifiSSID, naStr, sizeof(naStr)+1);
if(gSysCfg.wifiPwd)
free(gSysCfg.wifiPwd);
gSysCfg.wifiPwd = new char[sizeof(naStr)+1];
memcpy(gSysCfg.wifiPwd, naStr, sizeof(naStr)+1);
gSysCfg.dbgNumRestarts = 0;
gSysCfg.lastKnownTimeStamp = 0;
gSysCfg.timeZone = 2;
}
}
}
return challenge;
}
uint32 ICACHE_FLASH_ATTR os_random(void)
{
return phy_get_rand();
}
