1 files changed, 213 insertions, 0 deletions
diff --git a/src/Core/RandomNumberGenerator.cpp b/src/Core/RandomNumberGenerator.cpp
new file mode 100644
index 00000000..a010e7c6
--- /dev/null
+++ b/src/Core/RandomNumberGenerator.cpp
@@ -0,0 +1,213 @@
+/*
+ Copyright (c) 2008-2009 TrueCrypt Developers Association. All rights reserved.
+
+ Governed by the TrueCrypt License 3.0 the full text of which is contained in
+ the file License.txt included in TrueCrypt binary and source code distribution
+ packages.
+*/
+
+#ifndef TC_WINDOWS
+#include <sys/types.h>
+#include <errno.h>
+#include <fcntl.h>
+#endif
+
+#include "RandomNumberGenerator.h"
+#include "Volume/Crc32.h"
+
+namespace TrueCrypt
+{
+	void RandomNumberGenerator::AddSystemDataToPool (bool fast)
+	{
+		SecureBuffer buffer (PoolSize);
+
+#ifdef TC_WINDOWS
+#ifndef DEBUG
+		throw NotImplemented (SRC_POS);
+#endif
+#else
+		int urandom = open ("/dev/urandom", O_RDONLY);
+		throw_sys_sub_if (urandom == -1, L"/dev/urandom");
+		finally_do_arg (int, urandom, { close (finally_arg); });
+
+		throw_sys_sub_if (read (urandom, buffer, buffer.Size()) == -1, L"/dev/urandom");
+		AddToPool (buffer);
+
+		if (!fast)
+		{
+			// Read all bytes available in /dev/random up to buffer size
+			int random = open ("/dev/random", O_RDONLY | O_NONBLOCK);
+			throw_sys_sub_if (random == -1, L"/dev/random");
+			finally_do_arg (int, random, { close (finally_arg); });
+
+			throw_sys_sub_if (read (random, buffer, buffer.Size()) == -1 && errno != EAGAIN, L"/dev/random");
+			AddToPool (buffer);
+		}
+#endif
+	}
+
+	void RandomNumberGenerator::AddToPool (const ConstBufferPtr &data)
+	{
+		if (!Running)
+			throw NotInitialized (SRC_POS);
+
+		ScopeLock lock (AccessMutex);
+
+		for (size_t i = 0; i < data.Size(); ++i)
+		{
+			Pool[WriteOffset++] += data[i];
+
+			if (WriteOffset >= PoolSize)
+				WriteOffset = 0;
+
+			if (++BytesAddedSincePoolHashMix >= MaxBytesAddedBeforePoolHashMix)
+				HashMixPool();
+		}
+	}
+
+	void RandomNumberGenerator::GetData (const BufferPtr &buffer, bool fast)
+	{
+		if (!Running)
+			throw NotInitialized (SRC_POS);
+
+		if (buffer.Size() > PoolSize)
+			throw ParameterIncorrect (SRC_POS);
+
+		ScopeLock lock (AccessMutex);
+
+		// Poll system for data
+		AddSystemDataToPool (fast);
+		HashMixPool();
+
+		// Transfer bytes from pool to output buffer
+		for (size_t i = 0; i < buffer.Size(); ++i)
+		{
+			buffer[i] += Pool[ReadOffset++];
+
+			if (ReadOffset >= PoolSize)
+				ReadOffset = 0;
+		}
+
+		// Invert and mix the pool
+		for (size_t i = 0; i < Pool.Size(); ++i)
+		{
+			Pool[i] = ~Pool[i];
+		}
+
+		AddSystemDataToPool (true);
+		HashMixPool();
+
+		// XOR the current pool content into the output buffer to prevent pool state leaks
+		for (size_t i = 0; i < buffer.Size(); ++i)
+		{
+			buffer[i] ^= Pool[ReadOffset++];
+
+			if (ReadOffset >= PoolSize)
+				ReadOffset = 0;
+		}
+	}
+
+	shared_ptr <Hash> RandomNumberGenerator::GetHash ()
+	{
+		ScopeLock lock (AccessMutex);
+		return PoolHash;
+	}
+
+	void RandomNumberGenerator::HashMixPool ()
+	{
+		BytesAddedSincePoolHashMix = 0;
+
+		for (size_t poolPos = 0; poolPos < Pool.Size(); )
+		{
+			// Compute the message digest of the entire pool using the selected hash function
+			SecureBuffer digest (PoolHash->GetDigestSize());
+			PoolHash->ProcessData (Pool);
+			PoolHash->GetDigest (digest);
+
+			// Add the message digest to the pool
+			for (size_t digestPos = 0; digestPos < digest.Size() && poolPos < Pool.Size(); ++digestPos)
+			{
+				Pool[poolPos++] += digest[digestPos];
+			}
+		}
+	}
+
+	void RandomNumberGenerator::SetHash (shared_ptr <Hash> hash)
+	{
+		ScopeLock lock (AccessMutex);
+		PoolHash = hash;
+	}
+
+	void RandomNumberGenerator::Start ()
+	{
+		ScopeLock lock (AccessMutex);
+
+		if (IsRunning())
+			return;
+
+		BytesAddedSincePoolHashMix = 0;
+		ReadOffset = 0;
+		WriteOffset = 0;
+		Running = true;
+		EnrichedByUser = false;
+
+		Pool.Allocate (PoolSize);
+		Test();
+
+		if (!PoolHash)
+		{
+			// First hash algorithm is the default one
+			PoolHash = Hash::GetAvailableAlgorithms().front();
+		}
+
+		AddSystemDataToPool (true);
+	}
+
+	void RandomNumberGenerator::Stop ()
+	{		
+		ScopeLock lock (AccessMutex);
+
+		if (Pool.IsAllocated())
+			Pool.Free ();
+
+		PoolHash.reset();
+
+		EnrichedByUser = false;
+		Running = false;
+	}
+
+	void RandomNumberGenerator::Test ()
+	{
+		shared_ptr <Hash> origPoolHash = PoolHash;
+		PoolHash.reset (new Ripemd160());
+
+		Pool.Zero();
+		Buffer buffer (1);
+		for (size_t i = 0; i < PoolSize * 10; ++i)
+		{
+			buffer[0] = (byte) i;
+			AddToPool (buffer);
+		}
+
+		if (Crc32::ProcessBuffer (Pool) != 0x2de46d17)
+			throw TestFailed (SRC_POS);
+
+		buffer.Allocate (PoolSize);
+		buffer.CopyFrom (PeekPool());
+		AddToPool (buffer);
+
+		if (Crc32::ProcessBuffer (Pool) != 0xcb88e019)
+			throw TestFailed (SRC_POS);
+
+		PoolHash = origPoolHash;
+	}
+
+	Mutex RandomNumberGenerator::AccessMutex;
+	size_t RandomNumberGenerator::BytesAddedSincePoolHashMix;
+	bool RandomNumberGenerator::EnrichedByUser;
+	SecureBuffer RandomNumberGenerator::Pool;
+	shared_ptr <Hash> RandomNumberGenerator::PoolHash;
+	size_t RandomNumberGenerator::ReadOffset;
+	bool RandomNumberGenerator::Running = false;
+	size_t RandomNumberGenerator::WriteOffset;
+}