Refactor authentication code

3 files changed, 124 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 000000000..f81bd0c55
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/sasl/DigestMd5.java
@@ -0,0 +1,72 @@
+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 String getMechanism() {
+        return "DIGEST-MD5";
+    }
+
+    @Override
+    public String getResponse(final String challenge) {
+        final String encodedResponse;
+        try {
+            final String[] challengeParts = new String(Base64.decode(challenge,
+                    Base64.DEFAULT)).split(",");
+            String nonce = "";
+            for (int i = 0; i < challengeParts.length; ++i) {
+                String[] parts = challengeParts[i].split("=");
+                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) {
+            return "";
+        }
+
+        return encodedResponse;
+    }
+}
diff --git a/src/main/java/eu/siacs/conversations/crypto/sasl/Plain.java b/src/main/java/eu/siacs/conversations/crypto/sasl/Plain.java
new file mode 100644
index 000000000..e7760bbcf
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/sasl/Plain.java
@@ -0,0 +1,25 @@
+package eu.siacs.conversations.crypto.sasl;
+
+import android.util.Base64;
+
+import java.nio.charset.Charset;
+
+import eu.siacs.conversations.entities.Account;
+import eu.siacs.conversations.xml.TagWriter;
+
+public class Plain extends SaslMechanism {
+    public Plain(final TagWriter tagWriter, final Account account) {
+        super(tagWriter, account, null);
+    }
+
+    @Override
+    public String getMechanism() {
+        return "PLAIN";
+    }
+
+    @Override
+    public String getStartAuth() {
+        final String sasl = '\u0000' + account.getUsername() + '\u0000' + account.getPassword();
+        return Base64.encodeToString(sasl.getBytes(Charset.defaultCharset()), Base64.NO_WRAP);
+    }
+}
diff --git a/src/main/java/eu/siacs/conversations/crypto/sasl/SaslMechanism.java b/src/main/java/eu/siacs/conversations/crypto/sasl/SaslMechanism.java
new file mode 100644
index 000000000..5eddd5c23
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/sasl/SaslMechanism.java
@@ -0,0 +1,27 @@
+package eu.siacs.conversations.crypto.sasl;
+
+import java.security.SecureRandom;
+
+import eu.siacs.conversations.entities.Account;
+import eu.siacs.conversations.xml.TagWriter;
+
+public abstract class SaslMechanism {
+
+    final protected TagWriter tagWriter;
+    final protected Account account;
+    final protected SecureRandom rng;
+
+    public SaslMechanism(final TagWriter tagWriter, final Account account, final SecureRandom rng) {
+        this.tagWriter = tagWriter;
+        this.account = account;
+        this.rng = rng;
+    }
+
+    public abstract String getMechanism();
+    public String getStartAuth() {
+        return "";
+    }
+    public String getResponse(final String challenge) {
+        return "";
+    }
+}