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Code Issues Projects Releases Wiki Activity

Implement stream header for BTPv2. #111

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This commit is contained in:
akwizgran
2015-12-14 13:29:28 +00:00
parent 766179ac97
commit f2efe7f2ea
9 changed files with 591 additions and 233 deletions
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24
briar-core/src/org/briarproject/crypto/FrameEncoder.java
View File

@@ -1,27 +1,28 @@
package org.briarproject.crypto;
import static org.briarproject.api.transport.TransportConstants.HEADER_LENGTH;
import static org.briarproject.api.transport.TransportConstants.IV_LENGTH;
import org.briarproject.util.ByteUtils;
import static org.briarproject.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static org.briarproject.api.transport.TransportConstants.FRAME_IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAX_PAYLOAD_LENGTH;
import static org.briarproject.util.ByteUtils.MAX_32_BIT_UNSIGNED;
import org.briarproject.util.ByteUtils;
class FrameEncoder {
static void encodeIv(byte[] iv, long frameNumber, boolean header) {
if (iv.length < IV_LENGTH) throw new IllegalArgumentException();
if (iv.length < FRAME_IV_LENGTH) throw new IllegalArgumentException();
if (frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException();
ByteUtils.writeUint32(frameNumber, iv, 0);
if (header) iv[4] = 1;
else iv[4] = 0;
for (int i = 5; i < IV_LENGTH; i++) iv[i] = 0;
for (int i = 5; i < FRAME_IV_LENGTH; i++) iv[i] = 0;
}
static void encodeHeader(byte[] header, boolean finalFrame,
int payloadLength, int paddingLength) {
if (header.length < HEADER_LENGTH) throw new IllegalArgumentException();
if (header.length < FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
if (payloadLength < 0) throw new IllegalArgumentException();
if (paddingLength < 0) throw new IllegalArgumentException();
if (payloadLength + paddingLength > MAX_PAYLOAD_LENGTH)
@@ -32,17 +33,20 @@ class FrameEncoder {
}
static boolean isFinalFrame(byte[] header) {
if (header.length < HEADER_LENGTH) throw new IllegalArgumentException();
if (header.length < FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
return (header[0] & 0x80) == 0x80;
}
static int getPayloadLength(byte[] header) {
if (header.length < HEADER_LENGTH) throw new IllegalArgumentException();
if (header.length < FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
return ByteUtils.readUint16(header, 0) & 0x7FFF;
}
static int getPaddingLength(byte[] header) {
if (header.length < HEADER_LENGTH) throw new IllegalArgumentException();
if (header.length < FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
return ByteUtils.readUint16(header, 2);
}
}

79
briar-core/src/org/briarproject/crypto/StreamDecrypterImpl.java
View File

@@ -9,31 +9,34 @@ import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
import static org.briarproject.api.transport.TransportConstants.HEADER_LENGTH;
import static org.briarproject.api.transport.TransportConstants.IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static org.briarproject.api.transport.TransportConstants.FRAME_IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAC_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAX_PAYLOAD_LENGTH;
import static org.briarproject.api.transport.TransportConstants.STREAM_HEADER_IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.STREAM_HEADER_LENGTH;
// FIXME: Implementation is incomplete, doesn't read the stream header
class StreamDecrypterImpl implements StreamDecrypter {
private final InputStream in;
private final AuthenticatedCipher frameCipher;
private final SecretKey frameKey;
private final byte[] iv, frameHeader, frameCiphertext;
private final AuthenticatedCipher cipher;
private final SecretKey streamHeaderKey;
private final byte[] frameIv, frameHeader, frameCiphertext;
private SecretKey frameKey;
private long frameNumber;
private boolean finalFrame;
StreamDecrypterImpl(InputStream in, AuthenticatedCipher frameCipher,
SecretKey headerKey) {
StreamDecrypterImpl(InputStream in, AuthenticatedCipher cipher,
SecretKey streamHeaderKey) {
this.in = in;
this.frameCipher = frameCipher;
this.frameKey = headerKey; // FIXME
iv = new byte[IV_LENGTH];
frameHeader = new byte[HEADER_LENGTH];
this.cipher = cipher;
this.streamHeaderKey = streamHeaderKey;
frameIv = new byte[FRAME_IV_LENGTH];
frameHeader = new byte[FRAME_HEADER_LENGTH];
frameCiphertext = new byte[MAX_FRAME_LENGTH];
frameKey = null;
frameNumber = 0;
finalFrame = false;
}
@@ -43,20 +46,23 @@ class StreamDecrypterImpl implements StreamDecrypter {
if (payload.length < MAX_PAYLOAD_LENGTH)
throw new IllegalArgumentException();
if (finalFrame) return -1;
// Read the stream header if required
if (frameKey == null) readStreamHeader();
// Read the frame header
int offset = 0;
while (offset < HEADER_LENGTH) {
int read = in.read(frameCiphertext, offset, HEADER_LENGTH - offset);
while (offset < FRAME_HEADER_LENGTH) {
int read = in.read(frameCiphertext, offset,
FRAME_HEADER_LENGTH - offset);
if (read == -1) throw new EOFException();
offset += read;
}
// Decrypt and authenticate the frame header
FrameEncoder.encodeIv(iv, frameNumber, true);
FrameEncoder.encodeIv(frameIv, frameNumber, true);
try {
frameCipher.init(false, frameKey, iv);
int decrypted = frameCipher.process(frameCiphertext, 0,
HEADER_LENGTH, frameHeader, 0);
if (decrypted != HEADER_LENGTH - MAC_LENGTH)
cipher.init(false, frameKey, frameIv);
int decrypted = cipher.process(frameCiphertext, 0,
FRAME_HEADER_LENGTH, frameHeader, 0);
if (decrypted != FRAME_HEADER_LENGTH - MAC_LENGTH)
throw new RuntimeException();
} catch (GeneralSecurityException e) {
throw new FormatException();
@@ -68,7 +74,7 @@ class StreamDecrypterImpl implements StreamDecrypter {
if (payloadLength + paddingLength > MAX_PAYLOAD_LENGTH)
throw new FormatException();
// Read the payload and padding
int frameLength = HEADER_LENGTH + payloadLength + paddingLength
int frameLength = FRAME_HEADER_LENGTH + payloadLength + paddingLength
+ MAC_LENGTH;
while (offset < frameLength) {
int read = in.read(frameCiphertext, offset, frameLength - offset);
@@ -76,10 +82,10 @@ class StreamDecrypterImpl implements StreamDecrypter {
offset += read;
}
// Decrypt and authenticate the payload and padding
FrameEncoder.encodeIv(iv, frameNumber, false);
FrameEncoder.encodeIv(frameIv, frameNumber, false);
try {
frameCipher.init(false, frameKey, iv);
int decrypted = frameCipher.process(frameCiphertext, HEADER_LENGTH,
cipher.init(false, frameKey, frameIv);
int decrypted = cipher.process(frameCiphertext, FRAME_HEADER_LENGTH,
payloadLength + paddingLength + MAC_LENGTH, payload, 0);
if (decrypted != payloadLength + paddingLength)
throw new RuntimeException();
@@ -92,4 +98,31 @@ class StreamDecrypterImpl implements StreamDecrypter {
frameNumber++;
return payloadLength;
}
private void readStreamHeader() throws IOException {
byte[] streamHeaderIv = new byte[STREAM_HEADER_IV_LENGTH];
byte[] streamHeaderCiphertext = new byte[STREAM_HEADER_LENGTH];
byte[] streamHeaderPlaintext = new byte[SecretKey.LENGTH];
// Read the stream header
int offset = 0;
while (offset < STREAM_HEADER_LENGTH) {
int read = in.read(streamHeaderCiphertext, offset,
STREAM_HEADER_LENGTH - offset);
if (read == -1) throw new EOFException();
offset += read;
}
// Decrypt and authenticate the stream header
System.arraycopy(streamHeaderCiphertext, 0, streamHeaderIv, 0,
STREAM_HEADER_IV_LENGTH);
try {
cipher.init(false, streamHeaderKey, streamHeaderIv);
int decrypted = cipher.process(streamHeaderCiphertext,
STREAM_HEADER_IV_LENGTH, SecretKey.LENGTH + MAC_LENGTH,
streamHeaderPlaintext, 0);
if (decrypted != SecretKey.LENGTH) throw new RuntimeException();
} catch (GeneralSecurityException e) {
throw new FormatException();
}
frameKey = new SecretKey(streamHeaderPlaintext);
}
}

29
briar-core/src/org/briarproject/crypto/StreamEncrypterFactoryImpl.java
View File

@@ -1,18 +1,19 @@
package org.briarproject.crypto;
import static org.briarproject.api.transport.TransportConstants.TAG_LENGTH;
import java.io.OutputStream;
import javax.inject.Inject;
import javax.inject.Provider;
import org.briarproject.api.crypto.CryptoComponent;
import org.briarproject.api.crypto.SecretKey;
import org.briarproject.api.crypto.StreamEncrypter;
import org.briarproject.api.crypto.StreamEncrypterFactory;
import org.briarproject.api.transport.StreamContext;
import java.io.OutputStream;
import javax.inject.Inject;
import javax.inject.Provider;
import static org.briarproject.api.transport.TransportConstants.STREAM_HEADER_IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.TAG_LENGTH;
class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
private final CryptoComponent crypto;
@@ -27,15 +28,23 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
public StreamEncrypter createStreamEncrypter(OutputStream out,
StreamContext ctx) {
AuthenticatedCipher cipher = cipherProvider.get();
byte[] tag = new byte[TAG_LENGTH];
crypto.encodeTag(tag, ctx.getTagKey(), ctx.getStreamNumber());
AuthenticatedCipher cipher = cipherProvider.get();
return new StreamEncrypterImpl(out, cipher, ctx.getHeaderKey(), tag);
byte[] streamHeaderIv = new byte[STREAM_HEADER_IV_LENGTH];
crypto.getSecureRandom().nextBytes(streamHeaderIv);
SecretKey frameKey = crypto.generateSecretKey();
return new StreamEncrypterImpl(out, cipher, tag, streamHeaderIv,
ctx.getHeaderKey(), frameKey);
}
public StreamEncrypter createInvitationStreamEncrypter(OutputStream out,
SecretKey headerKey) {
AuthenticatedCipher cipher = cipherProvider.get();
return new StreamEncrypterImpl(out, cipher, headerKey, null);
byte[] streamHeaderIv = new byte[STREAM_HEADER_IV_LENGTH];
crypto.getSecureRandom().nextBytes(streamHeaderIv);
SecretKey frameKey = crypto.generateSecretKey();
return new StreamEncrypterImpl(out, cipher, null, streamHeaderIv,
headerKey, frameKey);
}
}

95
briar-core/src/org/briarproject/crypto/StreamEncrypterImpl.java
View File

@@ -7,35 +7,41 @@ import java.io.IOException;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import static org.briarproject.api.transport.TransportConstants.HEADER_LENGTH;
import static org.briarproject.api.transport.TransportConstants.IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static org.briarproject.api.transport.TransportConstants.FRAME_IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAC_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import static org.briarproject.api.transport.TransportConstants.MAX_PAYLOAD_LENGTH;
import static org.briarproject.api.transport.TransportConstants.STREAM_HEADER_IV_LENGTH;
import static org.briarproject.api.transport.TransportConstants.STREAM_HEADER_LENGTH;
import static org.briarproject.util.ByteUtils.MAX_32_BIT_UNSIGNED;
// FIXME: Implementation is incomplete, doesn't write the stream header
class StreamEncrypterImpl implements StreamEncrypter {
private final OutputStream out;
private final AuthenticatedCipher frameCipher;
private final SecretKey frameKey;
private final byte[] tag, iv, framePlaintext, frameCiphertext;
private final AuthenticatedCipher cipher;
private final SecretKey streamHeaderKey, frameKey;
private final byte[] tag, streamHeaderIv;
private final byte[] frameIv, framePlaintext, frameCiphertext;
private long frameNumber;
private boolean writeTag;
private boolean writeTag, writeStreamHeader;
StreamEncrypterImpl(OutputStream out, AuthenticatedCipher frameCipher,
SecretKey headerKey, byte[] tag) {
StreamEncrypterImpl(OutputStream out, AuthenticatedCipher cipher,
byte[] tag, byte[] streamHeaderIv, SecretKey streamHeaderKey,
SecretKey frameKey) {
this.out = out;
this.frameCipher = frameCipher;
this.frameKey = headerKey; // FIXME
this.cipher = cipher;
this.tag = tag;
iv = new byte[IV_LENGTH];
framePlaintext = new byte[HEADER_LENGTH + MAX_PAYLOAD_LENGTH];
this.streamHeaderIv = streamHeaderIv;
this.streamHeaderKey = streamHeaderKey;
this.frameKey = frameKey;
frameIv = new byte[FRAME_IV_LENGTH];
framePlaintext = new byte[FRAME_HEADER_LENGTH + MAX_PAYLOAD_LENGTH];
frameCiphertext = new byte[MAX_FRAME_LENGTH];
frameNumber = 0;
writeTag = (tag != null);
writeStreamHeader = true;
}
public void writeFrame(byte[] payload, int payloadLength,
@@ -45,52 +51,75 @@ class StreamEncrypterImpl implements StreamEncrypter {
// Don't allow the frame counter to wrap
if (frameNumber > MAX_32_BIT_UNSIGNED) throw new IOException();
// Write the tag if required
if (writeTag) {
out.write(tag, 0, tag.length);
writeTag = false;
}
if (writeTag) writeTag();
// Write the stream header if required
if (writeStreamHeader) writeStreamHeader();
// Encode the frame header
FrameEncoder.encodeHeader(framePlaintext, finalFrame, payloadLength,
paddingLength);
// Encrypt and authenticate the frame header
FrameEncoder.encodeIv(iv, frameNumber, true);
FrameEncoder.encodeIv(frameIv, frameNumber, true);
try {
frameCipher.init(true, frameKey, iv);
int encrypted = frameCipher.process(framePlaintext, 0,
HEADER_LENGTH - MAC_LENGTH, frameCiphertext, 0);
if (encrypted != HEADER_LENGTH) throw new RuntimeException();
cipher.init(true, frameKey, frameIv);
int encrypted = cipher.process(framePlaintext, 0,
FRAME_HEADER_LENGTH - MAC_LENGTH, frameCiphertext, 0);
if (encrypted != FRAME_HEADER_LENGTH) throw new RuntimeException();
} catch (GeneralSecurityException badCipher) {
throw new RuntimeException(badCipher);
}
// Combine the payload and padding
System.arraycopy(payload, 0, framePlaintext, HEADER_LENGTH,
System.arraycopy(payload, 0, framePlaintext, FRAME_HEADER_LENGTH,
payloadLength);
for (int i = 0; i < paddingLength; i++)
framePlaintext[HEADER_LENGTH + payloadLength + i] = 0;
framePlaintext[FRAME_HEADER_LENGTH + payloadLength + i] = 0;
// Encrypt and authenticate the payload and padding
FrameEncoder.encodeIv(iv, frameNumber, false);
FrameEncoder.encodeIv(frameIv, frameNumber, false);
try {
frameCipher.init(true, frameKey, iv);
int encrypted = frameCipher.process(framePlaintext, HEADER_LENGTH,
cipher.init(true, frameKey, frameIv);
int encrypted = cipher.process(framePlaintext, FRAME_HEADER_LENGTH,
payloadLength + paddingLength, frameCiphertext,
HEADER_LENGTH);
FRAME_HEADER_LENGTH);
if (encrypted != payloadLength + paddingLength + MAC_LENGTH)
throw new RuntimeException();
} catch (GeneralSecurityException badCipher) {
throw new RuntimeException(badCipher);
}
// Write the frame
out.write(frameCiphertext, 0, HEADER_LENGTH + payloadLength
out.write(frameCiphertext, 0, FRAME_HEADER_LENGTH + payloadLength
+ paddingLength + MAC_LENGTH);
frameNumber++;
}
private void writeTag() throws IOException {
out.write(tag, 0, tag.length);
writeTag = false;
}
private void writeStreamHeader() throws IOException {
byte[] streamHeaderPlaintext = frameKey.getBytes();
byte[] streamHeaderCiphertext = new byte[STREAM_HEADER_LENGTH];
System.arraycopy(streamHeaderIv, 0, streamHeaderCiphertext, 0,
STREAM_HEADER_IV_LENGTH);
// Encrypt and authenticate the frame key
try {
cipher.init(true, streamHeaderKey, streamHeaderIv);
int encrypted = cipher.process(streamHeaderPlaintext, 0,
SecretKey.LENGTH, streamHeaderCiphertext,
STREAM_HEADER_IV_LENGTH);
if (encrypted != SecretKey.LENGTH + MAC_LENGTH)
throw new RuntimeException();
} catch (GeneralSecurityException badCipher) {
throw new RuntimeException(badCipher);
}
out.write(streamHeaderCiphertext);
writeStreamHeader = false;
}
public void flush() throws IOException {
// Write the tag if required
if (writeTag) {
out.write(tag, 0, tag.length);
writeTag = false;
}
if (writeTag) writeTag();
// Write the stream header if required
if (writeStreamHeader) writeStreamHeader();
out.flush();
}
}