lbrycrd/src/random.cpp
Cory Fields 1630219d90 openssl: abstract out OPENSSL_cleanse
This makes it easier for us to replace it if desired, since it's now only in
one spot. Also, it avoids the openssl include from allocators.h, which
essentially forced openssl to be included from every compilation unit.
2015-02-15 11:34:02 -05:00

138 lines
3.9 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "random.h"
#include "support/cleanse.h"
#ifdef WIN32
#include "compat.h" // for Windows API
#endif
#include "serialize.h" // for begin_ptr(vec)
#include "util.h" // for LogPrint()
#include "utilstrencodings.h" // for GetTime()
#include <limits>
#ifndef WIN32
#include <sys/time.h>
#endif
#include <openssl/err.h>
#include <openssl/rand.h>
static inline int64_t GetPerformanceCounter()
{
int64_t nCounter = 0;
#ifdef WIN32
QueryPerformanceCounter((LARGE_INTEGER*)&nCounter);
#else
timeval t;
gettimeofday(&t, NULL);
nCounter = (int64_t)(t.tv_sec * 1000000 + t.tv_usec);
#endif
return nCounter;
}
void RandAddSeed()
{
// Seed with CPU performance counter
int64_t nCounter = GetPerformanceCounter();
RAND_add(&nCounter, sizeof(nCounter), 1.5);
memory_cleanse((void*)&nCounter, sizeof(nCounter));
}
void RandAddSeedPerfmon()
{
RandAddSeed();
// This can take up to 2 seconds, so only do it every 10 minutes
static int64_t nLastPerfmon;
if (GetTime() < nLastPerfmon + 10 * 60)
return;
nLastPerfmon = GetTime();
#ifdef WIN32
// Don't need this on Linux, OpenSSL automatically uses /dev/urandom
// Seed with the entire set of perfmon data
std::vector<unsigned char> vData(250000, 0);
long ret = 0;
unsigned long nSize = 0;
const size_t nMaxSize = 10000000; // Bail out at more than 10MB of performance data
while (true) {
nSize = vData.size();
ret = RegQueryValueExA(HKEY_PERFORMANCE_DATA, "Global", NULL, NULL, begin_ptr(vData), &nSize);
if (ret != ERROR_MORE_DATA || vData.size() >= nMaxSize)
break;
vData.resize(std::max((vData.size() * 3) / 2, nMaxSize)); // Grow size of buffer exponentially
}
RegCloseKey(HKEY_PERFORMANCE_DATA);
if (ret == ERROR_SUCCESS) {
RAND_add(begin_ptr(vData), nSize, nSize / 100.0);
memory_cleanse(begin_ptr(vData), nSize);
LogPrint("rand", "%s: %lu bytes\n", __func__, nSize);
} else {
static bool warned = false; // Warn only once
if (!warned) {
LogPrintf("%s: Warning: RegQueryValueExA(HKEY_PERFORMANCE_DATA) failed with code %i\n", __func__, ret);
warned = true;
}
}
#endif
}
void GetRandBytes(unsigned char* buf, int num)
{
if (RAND_bytes(buf, num) != 1) {
LogPrintf("%s: OpenSSL RAND_bytes() failed with error: %s\n", __func__, ERR_error_string(ERR_get_error(), NULL));
assert(false);
}
}
uint64_t GetRand(uint64_t nMax)
{
if (nMax == 0)
return 0;
// The range of the random source must be a multiple of the modulus
// to give every possible output value an equal possibility
uint64_t nRange = (std::numeric_limits<uint64_t>::max() / nMax) * nMax;
uint64_t nRand = 0;
do {
GetRandBytes((unsigned char*)&nRand, sizeof(nRand));
} while (nRand >= nRange);
return (nRand % nMax);
}
int GetRandInt(int nMax)
{
return GetRand(nMax);
}
uint256 GetRandHash()
{
uint256 hash;
GetRandBytes((unsigned char*)&hash, sizeof(hash));
return hash;
}
uint32_t insecure_rand_Rz = 11;
uint32_t insecure_rand_Rw = 11;
void seed_insecure_rand(bool fDeterministic)
{
// The seed values have some unlikely fixed points which we avoid.
if (fDeterministic) {
insecure_rand_Rz = insecure_rand_Rw = 11;
} else {
uint32_t tmp;
do {
GetRandBytes((unsigned char*)&tmp, 4);
} while (tmp == 0 || tmp == 0x9068ffffU);
insecure_rand_Rz = tmp;
do {
GetRandBytes((unsigned char*)&tmp, 4);
} while (tmp == 0 || tmp == 0x464fffffU);
insecure_rand_Rw = tmp;
}
}