1 files changed, 91 insertions, 0 deletions
diff --git a/src/main/java/eu/siacs/conversations/crypto/sasl/DigestMd5.java b/src/main/java/eu/siacs/conversations/crypto/sasl/DigestMd5.java
new file mode 100644
index 00000000..8b16215b
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/sasl/DigestMd5.java
@@ -0,0 +1,91 @@
+package eu.siacs.conversations.crypto.sasl;
+
+import android.util.Base64;
+
+import java.math.BigInteger;
+import java.nio.charset.Charset;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+
+import eu.siacs.conversations.entities.Account;
+import eu.siacs.conversations.utils.CryptoHelper;
+import eu.siacs.conversations.xml.TagWriter;
+
+public class DigestMd5 extends SaslMechanism {
+	public DigestMd5(final TagWriter tagWriter, final Account account, final SecureRandom rng) {
+		super(tagWriter, account, rng);
+	}
+
+	@Override
+	public int getPriority() {
+		return 10;
+	}
+
+	@Override
+	public String getMechanism() {
+		return "DIGEST-MD5";
+	}
+
+	private State state = State.INITIAL;
+
+	@Override
+	public String getResponse(final String challenge) throws AuthenticationException {
+		switch (state) {
+			case INITIAL:
+				state = State.RESPONSE_SENT;
+				final String encodedResponse;
+				try {
+					final Tokenizer tokenizer = new Tokenizer(Base64.decode(challenge, Base64.DEFAULT));
+					String nonce = "";
+					for (final String token : tokenizer) {
+						final String[] parts = token.split("=", 2);
+						if (parts[0].equals("nonce")) {
+							nonce = parts[1].replace("\"", "");
+						} else if (parts[0].equals("rspauth")) {
+							return "";
+						}
+					}
+					final String digestUri = "xmpp/" + account.getServer();
+					final String nonceCount = "00000001";
+					final String x = account.getUsername() + ":" + account.getServer() + ":"
+						+ account.getPassword();
+					final MessageDigest md = MessageDigest.getInstance("MD5");
+					final byte[] y = md.digest(x.getBytes(Charset.defaultCharset()));
+					final String cNonce = new BigInteger(100, rng).toString(32);
+					final byte[] a1 = CryptoHelper.concatenateByteArrays(y,
+							(":" + nonce + ":" + cNonce).getBytes(Charset.defaultCharset()));
+					final String a2 = "AUTHENTICATE:" + digestUri;
+					final String ha1 = CryptoHelper.bytesToHex(md.digest(a1));
+					final String ha2 = CryptoHelper.bytesToHex(md.digest(a2.getBytes(Charset
+									.defaultCharset())));
+					final String kd = ha1 + ":" + nonce + ":" + nonceCount + ":" + cNonce
+						+ ":auth:" + ha2;
+					final String response = CryptoHelper.bytesToHex(md.digest(kd.getBytes(Charset
+									.defaultCharset())));
+					final String saslString = "username=\"" + account.getUsername()
+						+ "\",realm=\"" + account.getServer() + "\",nonce=\""
+						+ nonce + "\",cnonce=\"" + cNonce + "\",nc=" + nonceCount
+						+ ",qop=auth,digest-uri=\"" + digestUri + "\",response="
+						+ response + ",charset=utf-8";
+					encodedResponse = Base64.encodeToString(
+							saslString.getBytes(Charset.defaultCharset()),
+							Base64.NO_WRAP);
+				} catch (final NoSuchAlgorithmException e) {
+					throw new AuthenticationException(e);
+				}
+
+				return encodedResponse;
+			case RESPONSE_SENT:
+				state = State.VALID_SERVER_RESPONSE;
+				break;
+			case VALID_SERVER_RESPONSE:
+				if (challenge==null) {
+					return null; //everything is fine
+				}
+			default:
+				throw new InvalidStateException(state);
+		}
+		return null;
+	}
+}