Add SCRAM-SHA1 support
Factor out GS2 tokanization into own class Add authentication exception class Fixes #71
This commit is contained in:
Sam Whited
parent
c61120bfc4
commit
0e550789d3
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@ -0,0 +1,11 @@
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package eu.siacs.conversations.crypto.sasl;
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public class AuthenticationException extends Exception {
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public AuthenticationException(final String message) {
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super(message);
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}
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public AuthenticationException(final Exception inner) {
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super(inner);
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}
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}
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@ -17,20 +17,28 @@ public class DigestMd5 extends SaslMechanism {
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super(tagWriter, account, rng);
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}
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@Override
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public String getMechanism() {
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public static String getMechanism() {
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return "DIGEST-MD5";
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}
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private enum State {
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INITIAL,
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RESPONSE_SENT,
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}
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private State state = State.INITIAL;
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@Override
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public String getResponse(final String challenge) {
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public String getResponse(final String challenge) throws AuthenticationException {
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switch (state) {
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case INITIAL:
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state = State.RESPONSE_SENT;
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final String encodedResponse;
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try {
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final String[] challengeParts = new String(Base64.decode(challenge,
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Base64.DEFAULT)).split(",");
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final Tokenizer tokenizer = new Tokenizer(Base64.decode(challenge, Base64.DEFAULT));
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String nonce = "";
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for (int i = 0; i < challengeParts.length; ++i) {
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String[] parts = challengeParts[i].split("=");
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for (final String token : tokenizer) {
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final String[] parts = token.split("=");
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if (parts[0].equals("nonce")) {
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nonce = parts[1].replace("\"", "");
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} else if (parts[0].equals("rspauth")) {
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@ -68,5 +76,9 @@ public class DigestMd5 extends SaslMechanism {
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}
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return encodedResponse;
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case RESPONSE_SENT:
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return "";
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}
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return "";
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}
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}
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@ -12,13 +12,12 @@ public class Plain extends SaslMechanism {
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super(tagWriter, account, null);
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}
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@Override
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public String getMechanism() {
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public static String getMechanism() {
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return "PLAIN";
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}
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@Override
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public String getStartAuth() {
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public String getClientFirstMessage() {
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final String sasl = '\u0000' + account.getUsername() + '\u0000' + account.getPassword();
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return Base64.encodeToString(sasl.getBytes(Charset.defaultCharset()), Base64.NO_WRAP);
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}
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@ -17,11 +17,10 @@ public abstract class SaslMechanism {
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this.rng = rng;
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}
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public abstract String getMechanism();
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public String getStartAuth() {
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public String getClientFirstMessage() {
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return "";
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}
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public String getResponse(final String challenge) {
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public String getResponse(final String challenge) throws AuthenticationException {
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return "";
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}
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}
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198
src/main/java/eu/siacs/conversations/crypto/sasl/ScramSha1.java
Normal file
198
src/main/java/eu/siacs/conversations/crypto/sasl/ScramSha1.java
Normal file
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@ -0,0 +1,198 @@
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package eu.siacs.conversations.crypto.sasl;
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import android.util.Base64;
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import org.bouncycastle.crypto.Digest;
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import org.bouncycastle.crypto.digests.SHA1Digest;
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import org.bouncycastle.crypto.macs.HMac;
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import org.bouncycastle.crypto.params.KeyParameter;
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import java.math.BigInteger;
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import java.nio.charset.Charset;
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import java.security.InvalidKeyException;
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import java.security.SecureRandom;
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import eu.siacs.conversations.entities.Account;
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import eu.siacs.conversations.utils.CryptoHelper;
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import eu.siacs.conversations.xml.TagWriter;
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public class ScramSha1 extends SaslMechanism {
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// TODO: When channel binding (SCRAM-SHA1-PLUS) is supported in future, generalize this to indicate support and/or usage.
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final private static String GS2_HEADER = "n,,";
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private String clientFirstMessageBare;
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private byte[] serverFirstMessage;
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final private String clientNonce;
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private byte[] serverSignature = null;
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private static HMac HMAC;
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private static Digest DIGEST;
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private static final byte[] CLIENT_KEY_BYTES = "Client Key".getBytes();
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private static final byte[] SERVER_KEY_BYTES = "Server Key".getBytes();
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static {
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DIGEST = new SHA1Digest();
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HMAC = new HMac(new SHA1Digest());
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}
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private enum State {
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INITIAL,
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AUTH_TEXT_SENT,
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RESPONSE_SENT,
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VALID_SERVER_RESPONSE,
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}
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private State state = State.INITIAL;
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public ScramSha1(final TagWriter tagWriter, final Account account, final SecureRandom rng) {
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super(tagWriter, account, rng);
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// This nonce should be different for each authentication attempt.
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clientNonce = new BigInteger(100, this.rng).toString(32);
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clientFirstMessageBare = "";
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}
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public static String getMechanism() {
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return "SCRAM-SHA-1";
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}
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@Override
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public String getClientFirstMessage() {
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if (clientFirstMessageBare.isEmpty()) {
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clientFirstMessageBare = "n=" + CryptoHelper.saslPrep(account.getUsername()) +
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",r=" + this.clientNonce;
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}
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if (state == State.INITIAL) {
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state = State.AUTH_TEXT_SENT;
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}
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return Base64.encodeToString(
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(GS2_HEADER + clientFirstMessageBare).getBytes(Charset.defaultCharset()),
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Base64.NO_WRAP);
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}
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@Override
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public String getResponse(final String challenge) throws AuthenticationException {
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switch (state) {
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case AUTH_TEXT_SENT:
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serverFirstMessage = Base64.decode(challenge, Base64.DEFAULT);
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final Tokenizer tokenizer = new Tokenizer(serverFirstMessage);
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String nonce = "";
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int iterationCount = -1;
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String salt = "";
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for (final String token : tokenizer) {
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if (token.charAt(1) == '=') {
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switch (token.charAt(0)) {
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case 'i':
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try {
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iterationCount = Integer.parseInt(token.substring(2));
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} catch (final NumberFormatException e) {
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throw new AuthenticationException(e);
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}
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break;
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case 's':
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salt = token.substring(2);
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break;
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case 'r':
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nonce = token.substring(2);
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break;
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case 'm':
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/*
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* RFC 5802:
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* m: This attribute is reserved for future extensibility. In this
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* version of SCRAM, its presence in a client or a server message
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* MUST cause authentication failure when the attribute is parsed by
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* the other end.
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*/
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throw new AuthenticationException("Server sent reserved token: `m'");
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}
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}
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}
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if (iterationCount < 0) {
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throw new AuthenticationException("Server did not send iteration count");
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}
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if (nonce.isEmpty() || !nonce.startsWith(clientNonce)) {
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throw new AuthenticationException("Server nonce does not contain client nonce: " + nonce);
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}
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if (salt.isEmpty()) {
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throw new AuthenticationException("Server sent empty salt");
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}
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final String clientFinalMessageWithoutProof = "c=" + Base64.encodeToString(
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GS2_HEADER.getBytes(), Base64.NO_WRAP) + ",r=" + nonce;
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final byte[] authMessage = (clientFirstMessageBare + ',' + new String(serverFirstMessage) + ','
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+ clientFinalMessageWithoutProof).getBytes();
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// TODO: In future, cache the clientKey and serverKey and re-use them on re-auth.
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final byte[] saltedPassword, clientSignature, serverKey, clientKey;
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try {
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saltedPassword = hi(CryptoHelper.saslPrep(account.getPassword()).getBytes(),
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Base64.decode(salt, Base64.DEFAULT), iterationCount);
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serverKey = hmac(saltedPassword, SERVER_KEY_BYTES);
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serverSignature = hmac(serverKey, authMessage);
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clientKey = hmac(saltedPassword, CLIENT_KEY_BYTES);
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final byte[] storedKey = digest(clientKey);
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clientSignature = hmac(storedKey, authMessage);
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} catch (final InvalidKeyException e) {
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throw new AuthenticationException(e);
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}
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final byte[] clientProof = new byte[clientKey.length];
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for (int i = 0; i < clientProof.length; i++) {
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clientProof[i] = (byte) (clientKey[i] ^ clientSignature[i]);
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}
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final String clientFinalMessage = clientFinalMessageWithoutProof + ",p=" +
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Base64.encodeToString(clientProof, Base64.NO_WRAP);
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state = State.RESPONSE_SENT;
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return Base64.encodeToString(clientFinalMessage.getBytes(), Base64.NO_WRAP);
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case RESPONSE_SENT:
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final String clientCalculatedServerFinalMessage = "v=" +
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Base64.encodeToString(serverSignature, Base64.NO_WRAP);
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if (!clientCalculatedServerFinalMessage.equals(new String(Base64.decode(challenge, Base64.DEFAULT)))) {
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throw new AuthenticationException("Server final message does not match calculated final message");
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}
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state = State.VALID_SERVER_RESPONSE;
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return "";
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default:
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throw new AuthenticationException("Invalid state: " + state);
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}
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}
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public static synchronized byte[] hmac(final byte[] key, final byte[] input)
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throws InvalidKeyException {
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HMAC.init(new KeyParameter(key));
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HMAC.update(input, 0, input.length);
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final byte[] out = new byte[HMAC.getMacSize()];
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HMAC.doFinal(out, 0);
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return out;
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}
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public static synchronized byte[] digest(byte[] bytes) {
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DIGEST.reset();
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DIGEST.update(bytes, 0, bytes.length);
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final byte[] out = new byte[DIGEST.getDigestSize()];
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DIGEST.doFinal(out, 0);
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return out;
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}
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/*
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* Hi() is, essentially, PBKDF2 [RFC2898] with HMAC() as the
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* pseudorandom function (PRF) and with dkLen == output length of
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* HMAC() == output length of H().
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*/
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private static synchronized byte[] hi(final byte[] key, final byte[] salt, final int iterations)
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throws InvalidKeyException {
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byte[] u = hmac(key, CryptoHelper.concatenateByteArrays(salt, CryptoHelper.ONE));
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byte[] out = u.clone();
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for (int i = 1; i < iterations; i++) {
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u = hmac(key, u);
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for (int j = 0; j < u.length; j++) {
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out[j] ^= u[j];
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}
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}
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return out;
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}
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}
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@ -0,0 +1,76 @@
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package eu.siacs.conversations.crypto.sasl;
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import android.util.Base64;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Iterator;
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import java.util.List;
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import java.util.NoSuchElementException;
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/**
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* A tokenizer for GS2 header strings
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*/
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public final class Tokenizer implements Iterator<String>, Iterable<String> {
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private final List<String> parts;
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private int index;
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public Tokenizer(final byte[] challenge) {
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final String challengeString = new String(challenge);
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parts = new ArrayList<>(Arrays.asList(challengeString.split(",")));
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index = 0;
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}
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/**
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* Returns true if there is at least one more element, false otherwise.
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*
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* @see #next
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*/
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@Override
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public boolean hasNext() {
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return parts.size() != index + 1;
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}
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/**
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* Returns the next object and advances the iterator.
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*
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* @return the next object.
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* @throws java.util.NoSuchElementException if there are no more elements.
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* @see #hasNext
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*/
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@Override
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public String next() {
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if (hasNext()) {
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return parts.get(index++);
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} else {
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throw new NoSuchElementException("No such element. Size is: " + parts.size());
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}
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}
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/**
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* Removes the last object returned by {@code next} from the collection.
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* This method can only be called once between each call to {@code next}.
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*
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* @throws UnsupportedOperationException if removing is not supported by the collection being
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* iterated.
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* @throws IllegalStateException if {@code next} has not been called, or {@code remove} has
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* already been called after the last call to {@code next}.
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*/
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@Override
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public void remove() {
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if(index <= 0) {
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throw new IllegalStateException("You can't delete an element before first next() method call");
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}
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parts.remove(--index);
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}
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/**
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* Returns an {@link java.util.Iterator} for the elements in this object.
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*
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* @return An {@code Iterator} instance.
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*/
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@Override
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public Iterator<String> iterator() {
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return parts.iterator();
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}
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}
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@ -1,13 +1,14 @@
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package eu.siacs.conversations.utils;
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import java.security.SecureRandom;
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import java.text.Normalizer;
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public class CryptoHelper {
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public static final String FILETRANSFER = "?FILETRANSFERv1:";
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final protected static char[] hexArray = "0123456789abcdef".toCharArray();
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final protected static char[] vowels = "aeiou".toCharArray();
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final protected static char[] consonants = "bcdfghjklmnpqrstvwxyz"
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.toCharArray();
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final protected static char[] consonants = "bcdfghjklmnpqrstvwxyz".toCharArray();
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final public static byte[] ONE = new byte[] { 0, 0, 0, 1 };
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public static String bytesToHex(byte[] bytes) {
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char[] hexChars = new char[bytes.length * 2];
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@ -51,4 +52,30 @@ public class CryptoHelper {
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}
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return builder.toString();
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}
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/**
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* Escapes usernames or passwords for SASL.
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*/
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public static String saslEscape(final String s) {
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final StringBuilder sb = new StringBuilder((int) (s.length() * 1.1));
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for (int i = 0; i < s.length(); i++) {
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char c = s.charAt(i);
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switch (c) {
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case ',':
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sb.append("=2C");
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break;
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case '=':
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sb.append("=3D");
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break;
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default:
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sb.append(c);
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break;
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}
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}
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return sb.toString();
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}
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public static String saslPrep(final String s) {
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return saslEscape(Normalizer.normalize(s, Normalizer.Form.NFKC));
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}
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}
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@ -39,9 +39,11 @@ import javax.net.ssl.SSLSocketFactory;
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import javax.net.ssl.X509TrustManager;
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import eu.siacs.conversations.Config;
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import eu.siacs.conversations.crypto.sasl.AuthenticationException;
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import eu.siacs.conversations.crypto.sasl.DigestMd5;
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import eu.siacs.conversations.crypto.sasl.Plain;
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import eu.siacs.conversations.crypto.sasl.SaslMechanism;
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import eu.siacs.conversations.crypto.sasl.ScramSha1;
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import eu.siacs.conversations.entities.Account;
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import eu.siacs.conversations.services.XmppConnectionService;
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import eu.siacs.conversations.utils.DNSHelper;
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@ -271,6 +273,7 @@ public class XmppConnection implements Runnable {
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private void processStream(final Tag currentTag) throws XmlPullParserException,
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IOException, NoSuchAlgorithmException {
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Tag nextTag = tagReader.readTag();
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while ((nextTag != null) && (!nextTag.isEnd("stream"))) {
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if (nextTag.isStart("error")) {
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processStreamError(nextTag);
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@ -282,7 +285,13 @@ public class XmppConnection implements Runnable {
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switchOverToZLib(nextTag);
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} else if (nextTag.isStart("success")) {
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Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": logged in");
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tagReader.readTag();
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final String challenge = tagReader.readElement(nextTag).getContent();
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try {
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saslMechanism.getResponse(challenge);
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} catch (final AuthenticationException e) {
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disconnect(true);
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Log.e(Config.LOGTAG, String.valueOf(e));
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}
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tagReader.reset();
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sendStartStream();
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processStream(tagReader.readTag());
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@ -295,7 +304,12 @@ public class XmppConnection implements Runnable {
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final Element response = new Element("response");
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response.setAttribute("xmlns",
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"urn:ietf:params:xml:ns:xmpp-sasl");
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try {
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response.setContent(saslMechanism.getResponse(challenge));
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} catch (final AuthenticationException e) {
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// TODO: Send auth abort tag.
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Log.e(Config.LOGTAG, e.toString());
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}
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tagWriter.writeElement(response);
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} else if (nextTag.isStart("enabled")) {
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Element enabled = tagReader.readElement(nextTag);
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@ -616,13 +630,22 @@ public class XmppConnection implements Runnable {
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.findChild("mechanisms"));
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final Element auth = new Element("auth");
|
||||
auth.setAttribute("xmlns", "urn:ietf:params:xml:ns:xmpp-sasl");
|
||||
if (mechanisms.contains("DIGEST-MD5")) {
|
||||
if (mechanisms.contains(ScramSha1.getMechanism())) {
|
||||
saslMechanism = new ScramSha1(tagWriter, account, mXmppConnectionService.getRNG());
|
||||
Log.d(Config.LOGTAG, "Authenticating with " + ScramSha1.getMechanism());
|
||||
auth.setAttribute("mechanism", ScramSha1.getMechanism());
|
||||
} else if (mechanisms.contains(DigestMd5.getMechanism())) {
|
||||
Log.d(Config.LOGTAG, "Authenticating with " + DigestMd5.getMechanism());
|
||||
saslMechanism = new DigestMd5(tagWriter, account, mXmppConnectionService.getRNG());
|
||||
} else if (mechanisms.contains("PLAIN")) {
|
||||
auth.setAttribute("mechanism", DigestMd5.getMechanism());
|
||||
} else if (mechanisms.contains(Plain.getMechanism())) {
|
||||
Log.d(Config.LOGTAG, "Authenticating with " + Plain.getMechanism());
|
||||
saslMechanism = new Plain(tagWriter, account);
|
||||
auth.setContent(((Plain)saslMechanism).getStartAuth());
|
||||
auth.setAttribute("mechanism", Plain.getMechanism());
|
||||
}
|
||||
if (!saslMechanism.getClientFirstMessage().isEmpty()) {
|
||||
auth.setContent(saslMechanism.getClientFirstMessage());
|
||||
}
|
||||
auth.setAttribute("mechanism", saslMechanism.getMechanism());
|
||||
tagWriter.writeElement(auth);
|
||||
} else if (this.streamFeatures.hasChild("sm", "urn:xmpp:sm:"
|
||||
+ smVersion)
|
||||
|
|
|
|||
|
|
@ -117,7 +117,7 @@ public final class Jid {
|
|||
finaljid = finaljid + dp;
|
||||
}
|
||||
|
||||
// Remove trailling "." before storing the domain part.
|
||||
// Remove trailing "." before storing the domain part.
|
||||
if (dp.endsWith(".")) {
|
||||
try {
|
||||
domainpart = IDN.toASCII(dp.substring(0, dp.length() - 1), IDN.USE_STD3_ASCII_RULES);
|
||||
|
|
|
|||
Loading…
Reference in a new issue