|
private BCryptGenRandom ( |
||
| hAlgorithm | ||
| pbBuffer | [ | |
| cbBuffer | int | |
| dwFlags | int | |
| return | NTSTATUS | |
}//NextBytes()
void NextBytesInternal(ArraySegment<byte> bufferSegment)
{
BCrypt.NTSTATUS status;
var buffer = bufferSegment.Array;
var offset = bufferSegment.Offset;
var count = bufferSegment.Count;
if (count > CACHE_THRESHOLD)
{
status = (offset == 0) ? BCrypt.BCryptGenRandom(buffer, count) : BCrypt.BCryptGenRandom_PinnedBuffer(buffer, offset, count);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS) return;
throw new CryptographicException((int)status);
}
lock (_byteCache)
{
if (_byteCachePosition + count <= BYTE_CACHE_SIZE)
{
Utils.BlockCopy(_byteCache, _byteCachePosition, buffer, offset, count);
_byteCachePosition += count;
return;
}
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = count;
Utils.BlockCopy(_byteCache, 0, buffer, offset, count);
return;
}
throw new CryptographicException((int)status);
}// lock
}//NextBytesInternal()
}//NextBytes()
void NextBytesInternal(byte[] buffer, int offset, int count)
{
BCrypt.NTSTATUS status;
if (count > CACHE_THRESHOLD)
{
status = (offset == 0) ? BCrypt.BCryptGenRandom(buffer, count) : BCrypt.BCryptGenRandom_WithOffset(buffer, offset, count);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS) return;
ThrowNewCryptographicException((int)status);
}
lock (_byteCache)
{
if (_byteCachePosition + count <= BYTE_CACHE_SIZE)
{
Utils.BlockCopy(_byteCache, _byteCachePosition, buffer, offset, count);
_byteCachePosition += count;
return;
}
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = count;
Utils.BlockCopy(_byteCache, 0, buffer, offset, count);
return;
}
ThrowNewCryptographicException((int)status);
}// lock
}//NextBytesInternal()
}//GetRandomUInt()
/// <summary>
/// Gets one random unsigned 64bit integer in a thread safe manner.
/// </summary>
ulong GetRandomULong()
{
BCrypt.NTSTATUS status;
while (true)
{
int currentByteCachePosition = Interlocked.Add(ref _byteCachePosition, sizeof(ulong));
if (currentByteCachePosition <= BYTE_CACHE_SIZE && currentByteCachePosition > 0)
return BitConverter.ToUInt64(_byteCache, currentByteCachePosition - sizeof(ulong));
lock (_byteCache)
{
currentByteCachePosition = _byteCachePosition; // atomic read
if (currentByteCachePosition > (BYTE_CACHE_SIZE - sizeof(ulong)) || currentByteCachePosition <= 0)
{
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = sizeof(ulong); // atomic write
return BitConverter.ToUInt64(_byteCache, 0);
}
// defensive logic to prevent _byteCachePosition from wrapping into valid range due to BCryptGenRandom failures
if (currentByteCachePosition > BYTE_CACHE_SIZE || currentByteCachePosition < 0) _byteCachePosition = BYTE_CACHE_SIZE;
throw new CryptographicException((int)status);
}// if outside the valid range
}// lock
}// while(true)
}//GetRandomULong()
}//NextBytesInternal()
#if (NETCOREAPP2_1 || NETSTANDARD2_1)
void NextBytesInternal_Span(Span<byte> buffer, int count)
{
BCrypt.NTSTATUS status;
if (count > CACHE_THRESHOLD)
{
status = BCrypt.BCryptGenRandom_Span(buffer);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS) return;
ThrowNewCryptographicException((int)status);
}
lock (_byteCache)
{
if (_byteCachePosition + count <= BYTE_CACHE_SIZE)
{
new Span<byte>(_byteCache, _byteCachePosition, count).CopyTo(buffer);
_byteCachePosition += count;
return;
}
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = count;
new Span<byte>(_byteCache, 0, count).CopyTo(buffer);
return;
}
ThrowNewCryptographicException((int)status);
}// lock
}//NextBytesInternal_Span()
}// ctor
static void SanityCheck()
{
var testBuffer = new byte[BYTE_CACHE_SIZE / 2];
int status, i, j;
const int COLLISION_FREE_BLOCK_SIZE = 16;
status = (int)BCrypt.BCryptGenRandom(testBuffer, testBuffer.Length);
if (status != (int)BCrypt.NTSTATUS.STATUS_SUCCESS) throw new CryptographicException(status);
if (testBuffer.Length < COLLISION_FREE_BLOCK_SIZE * 2) return; // should be compiled away
for (i = 0; i < testBuffer.Length - COLLISION_FREE_BLOCK_SIZE; i += COLLISION_FREE_BLOCK_SIZE)
{
for (j = 0, status = 0; j < COLLISION_FREE_BLOCK_SIZE; ++j)
status |= testBuffer[i + j] ^ testBuffer[i + j + COLLISION_FREE_BLOCK_SIZE];
if (status == 0) throw new CryptographicException("CryptoRandom failed sanity check #2.");
}
}// SanityCheck()
void NextBytesInternal(ArraySegment<byte> bufferSegment)
{
BCrypt.NTSTATUS status;
var buffer = bufferSegment.Array;
var offset = bufferSegment.Offset;
var count = bufferSegment.Count;
if (count > CACHE_THRESHOLD)
{
status = (offset == 0) ? BCrypt.BCryptGenRandom(buffer, count) : BCrypt.BCryptGenRandom_PinnedBuffer(buffer, offset, count);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS) return;
throw new CryptographicException((int)status);
}
while (true)
{
int currentByteCachePosition = Interlocked.Add(ref _byteCachePosition, count);
if (currentByteCachePosition <= BYTE_CACHE_SIZE && currentByteCachePosition > 0)
{
Utils.BlockCopy(_byteCache, currentByteCachePosition - count, buffer, 0, count);
return;
}
lock (_byteCache)
{
currentByteCachePosition = _byteCachePosition; // atomic read
if (currentByteCachePosition > (BYTE_CACHE_SIZE - count) || currentByteCachePosition <= 0)
{
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = count; // atomic write
Utils.BlockCopy(_byteCache, 0, buffer, 0, count);
return;
}
// defensive logic to prevent _byteCachePosition from wrapping into valid range due to BCryptGenRandom failures
if (currentByteCachePosition > BYTE_CACHE_SIZE || currentByteCachePosition < 0) _byteCachePosition = BYTE_CACHE_SIZE;
throw new CryptographicException((int)status);
}// if outside the valid range
}// lock
}// while(true)
}//NextBytes()
internal static NTSTATUS BCryptGenRandom_PinnedBuffer(byte[] pbBuffer, int obBuffer, int cbBuffer)
{
Debug.Assert(pbBuffer != null);
Debug.Assert(cbBuffer >= 0 && obBuffer >= 0 && (obBuffer + cbBuffer) <= pbBuffer.Length);
GCHandle pinnedBufferHandle = default;
NTSTATUS status;
try
{
pinnedBufferHandle = GCHandle.Alloc(pbBuffer, GCHandleType.Pinned);
status = BCrypt.BCryptGenRandom(IntPtr.Zero, pinnedBufferHandle.AddrOfPinnedObject() + obBuffer, cbBuffer, BCRYPT_USE_SYSTEM_PREFERRED_RNG);
}
finally
{
if (pinnedBufferHandle.IsAllocated) pinnedBufferHandle.Free();
}
return status;
}// BCryptGenRandom()
}//GetRandomInt()
/// <summary>
/// Gets one random signed 64bit integer in a thread safe manner.
/// </summary>
long GetRandomLong()
{
lock (_byteCache)
{
if (_byteCachePosition + sizeof(long) <= BYTE_CACHE_SIZE)
{
var result = BitConverter.ToInt64(_byteCache, _byteCachePosition);
_byteCachePosition += sizeof(long);
return result;
}
BCrypt.NTSTATUS status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = sizeof(long);
return BitConverter.ToInt64(_byteCache, 0);
}
throw new CryptographicException((int)status);
}// lock
}//GetRandomLong()
}//NextBytesInternal()
/// <summary>
/// Gets one random signed 32bit integer in a thread safe manner.
/// </summary>
int GetRandomInt()
{
lock (_byteCache)
{
if (_byteCachePosition + sizeof(int) <= BYTE_CACHE_SIZE)
{
var result = Unsafe.As<byte, int>(ref _byteCache[_byteCachePosition]);//BitConverter.ToInt32(_byteCache, _byteCachePosition);
_byteCachePosition += sizeof(int);
return result;
}
BCrypt.NTSTATUS status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = sizeof(int);
return Unsafe.As<byte, int>(ref _byteCache[0]);//BitConverter.ToInt32(_byteCache, 0);
}
return ThrowNewCryptographicException((int)status);
}// lock
}//GetRandomInt()
