Refactor the ciphertext message parsing and building.
Moxie Marlinspike
11 years ago
parent
6e640db39c
commit
dbc070cd65
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package org.whispersystems.textsecure.crypto.protocol;
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import org.whispersystems.textsecure.crypto.InvalidMacException;
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import org.whispersystems.textsecure.crypto.InvalidMessageException;
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import org.whispersystems.textsecure.crypto.MessageMac;
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import org.whispersystems.textsecure.crypto.PublicKey;
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import org.whispersystems.textsecure.crypto.SessionCipher;
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import org.whispersystems.textsecure.util.Conversions;
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public class CiphertextMessage {
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public static final int SUPPORTED_VERSION = 2;
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public static final int CRADLE_AGREEMENT_VERSION = 2;
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static final int VERSION_LENGTH = 1;
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private static final int SENDER_KEY_ID_LENGTH = 3;
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private static final int RECEIVER_KEY_ID_LENGTH = 3;
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private static final int NEXT_KEY_LENGTH = PublicKey.KEY_SIZE;
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private static final int COUNTER_LENGTH = 3;
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private static final int HEADER_LENGTH = VERSION_LENGTH + SENDER_KEY_ID_LENGTH +
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RECEIVER_KEY_ID_LENGTH + COUNTER_LENGTH +
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NEXT_KEY_LENGTH;
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static final int VERSION_OFFSET = 0;
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private static final int SENDER_KEY_ID_OFFSET = VERSION_OFFSET + VERSION_LENGTH;
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private static final int RECEIVER_KEY_ID_OFFSET = SENDER_KEY_ID_OFFSET + SENDER_KEY_ID_LENGTH;
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private static final int NEXT_KEY_OFFSET = RECEIVER_KEY_ID_OFFSET + RECEIVER_KEY_ID_LENGTH;
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private static final int COUNTER_OFFSET = NEXT_KEY_OFFSET + NEXT_KEY_LENGTH;
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private static final int BODY_OFFSET = COUNTER_OFFSET + COUNTER_LENGTH;
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public static final int ENCRYPTED_MESSAGE_OVERHEAD = HEADER_LENGTH + MessageMac.MAC_LENGTH;
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private final byte[] ciphertext;
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public CiphertextMessage(SessionCipher.SessionCipherContext sessionContext, byte[] ciphertextBody) {
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this.ciphertext = new byte[HEADER_LENGTH + ciphertextBody.length + MessageMac.MAC_LENGTH];
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setVersion(sessionContext.getMessageVersion(), SUPPORTED_VERSION);
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setSenderKeyId(sessionContext.getSenderKeyId());
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setReceiverKeyId(sessionContext.getRecipientKeyId());
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setNextKeyBytes(sessionContext.getNextKey().serialize());
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setCounter(sessionContext.getCounter());
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setBody(ciphertextBody);
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setMac(MessageMac.calculateMac(ciphertext, 0, ciphertext.length - MessageMac.MAC_LENGTH,
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sessionContext.getSessionKey().getMacKey()));
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}
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public CiphertextMessage(byte[] ciphertext) throws InvalidMessageException {
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this.ciphertext = ciphertext;
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if (ciphertext.length < HEADER_LENGTH) {
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throw new InvalidMessageException("Not long enough for ciphertext header!");
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}
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if (getCurrentVersion() > SUPPORTED_VERSION) {
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throw new InvalidMessageException("Unspported version: " + getCurrentVersion());
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}
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}
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public void setVersion(int current, int supported) {
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ciphertext[VERSION_OFFSET] = Conversions.intsToByteHighAndLow(current, supported);
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}
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public int getCurrentVersion() {
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return Conversions.highBitsToInt(ciphertext[VERSION_OFFSET]);
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}
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public int getSupportedVersion() {
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return Conversions.lowBitsToInt(ciphertext[VERSION_OFFSET]);
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}
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public void setSenderKeyId(int senderKeyId) {
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Conversions.mediumToByteArray(ciphertext, SENDER_KEY_ID_OFFSET, senderKeyId);
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}
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public int getSenderKeyId() {
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return Conversions.byteArrayToMedium(ciphertext, SENDER_KEY_ID_OFFSET);
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}
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public void setReceiverKeyId(int receiverKeyId) {
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Conversions.mediumToByteArray(ciphertext, RECEIVER_KEY_ID_OFFSET, receiverKeyId);
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}
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public int getReceiverKeyId() {
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return Conversions.byteArrayToMedium(ciphertext, RECEIVER_KEY_ID_OFFSET);
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}
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public void setNextKeyBytes(byte[] nextKey) {
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assert(nextKey.length == NEXT_KEY_LENGTH);
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System.arraycopy(nextKey, 0, ciphertext, NEXT_KEY_OFFSET, nextKey.length);
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}
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public byte[] getNextKeyBytes() {
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byte[] nextKeyBytes = new byte[NEXT_KEY_LENGTH];
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System.arraycopy(ciphertext, NEXT_KEY_OFFSET, nextKeyBytes, 0, nextKeyBytes.length);
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return nextKeyBytes;
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}
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public void setCounter(int counter) {
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Conversions.mediumToByteArray(ciphertext, COUNTER_OFFSET, counter);
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}
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public int getCounter() {
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return Conversions.byteArrayToMedium(ciphertext, COUNTER_OFFSET);
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}
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public void setBody(byte[] body) {
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System.arraycopy(body, 0, ciphertext, BODY_OFFSET, body.length);
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}
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public byte[] getBody() {
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byte[] body = new byte[ciphertext.length - HEADER_LENGTH - MessageMac.MAC_LENGTH];
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System.arraycopy(ciphertext, BODY_OFFSET, body, 0, body.length);
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return body;
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}
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public void setMac(byte[] mac) {
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System.arraycopy(mac, 0, ciphertext, ciphertext.length-mac.length, mac.length);
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}
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public byte[] getMac() {
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byte[] mac = new byte[MessageMac.MAC_LENGTH];
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System.arraycopy(ciphertext, ciphertext.length-mac.length, mac, 0, mac.length);
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return mac;
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}
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public byte[] serialize() {
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return ciphertext;
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}
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public void verifyMac(SessionCipher.SessionCipherContext sessionContext)
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throws InvalidMessageException
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{
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try {
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MessageMac.verifyMac(this.ciphertext, 0, this.ciphertext.length - MessageMac.MAC_LENGTH,
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getMac(), sessionContext.getSessionKey().getMacKey());
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} catch (InvalidMacException e) {
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throw new InvalidMessageException(e);
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}
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}
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}
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@ -0,0 +1,20 @@
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package org.whispersystems.textsecure.push;
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public class PushBody {
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private final int type;
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private final byte[] body;
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public PushBody(int type, byte[] body) {
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this.type = type;
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this.body = body;
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}
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public int getType() {
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return type;
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}
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public byte[] getBody() {
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return body;
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}
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}
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