mumble/src/CryptographicRandom.cpp
2018-01-01 23:05:37 +01:00

44 lines
1.7 KiB
C++

// Copyright 2005-2018 The Mumble Developers. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file at the root of the
// Mumble source tree or at <https://www.mumble.info/LICENSE>.
#include "murmur_pch.h"
#include "CryptographicRandom.h"
#include "arc4random_uniform.h"
void CryptographicRandom::fillBuffer(void *buf, int numBytes) {
// We treat negative and zero values of numBytes to be
// fatal errors in the program. Abort the program if such
// a value is passed to fillBuffer().
if (numBytes <= 0) {
qFatal("CryptographicRandom::fillBuffer(): numBytes is <= 0");
}
// RAND_bytes only returns an error if the entropy pool has not yet been sufficiently filled,
// or in the case of a catastrophic, unrecoverable error in the RAND_bytes implementation happens.
// OpenSSL needs at least 32-bytes of high-entropy random data to seed its CSPRNG.
// If OpenSSL cannot acquire enough random data to seed its CSPRNG at the time Mumble and Murmur
// are running, there is not much we can do about it other than aborting the program.
if (RAND_bytes(reinterpret_cast<unsigned char *>(buf), static_cast<int>(numBytes)) != 1) {
qFatal("CryptographicRandom::fillBuffer(): internal error in OpenSSL's RAND_bytes or entropy pool not yet filled.");
}
}
uint32_t CryptographicRandom::uint32() {
uint32_t ret = 0;
unsigned char buf[4];
CryptographicRandom::fillBuffer(buf, sizeof(buf));
ret = (buf[0]) | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
return ret;
}
uint32_t CryptographicRandom::uniform(uint32_t upperBound) {
// Implemented in 3rdparty/arc4random/arc4random_uniform.c
return mumble_arc4random_uniform(upperBound);
}