Implement HMAC verification

src/main/java/dslab/Message.java

@@ -1,8 +1,17 @@
 package dslab;
 
 import dslab.exception.MissingInputException;
+import dslab.util.Keys;
 
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
+import java.util.Base64;
 import java.util.stream.Collectors;
 
 public class Message {
@@ -89,6 +98,23 @@ public class Message {
         this.hash = hash;
     }
 
+    /**
+     * Calculate a HMAC hash of the message.
+     *
+     * @return A Base64 encoded hash of the message.
+     * @throws IOException              Thrown if the HMAC key (in "keys/hmac.key") cannot be found.
+     * @throws NoSuchAlgorithmException Thrown if HmacSHA256 is not known.
+     * @throws InvalidKeyException      Thrown if the key is not valid.
+     */
+    public String calculateHash() throws IOException, NoSuchAlgorithmException, InvalidKeyException {
+        byte[] hashFormat = String.join("\n", getFrom().toString(), printTo(), getSubject(), getData())
+                .getBytes(StandardCharsets.UTF_8);
+        Mac mac = Mac.getInstance("HmacSHA256");
+        SecretKeySpec hmac = Keys.readSecretKey(new File("keys/hmac.key"));
+        mac.init(hmac);
+        return (Base64.getEncoder().encodeToString(mac.doFinal(hashFormat)));
+    }
+
     public String listMessage() {
         return getId() + " " + getFrom() + " " + getSubject();
     }

src/main/java/dslab/client/MessageClient.java

@@ -10,13 +10,17 @@ import java.security.spec.InvalidKeySpecException;
 import java.security.spec.X509EncodedKeySpec;
 import java.util.Arrays;
 import java.util.Base64;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import at.ac.tuwien.dsg.orvell.Shell;
 import at.ac.tuwien.dsg.orvell.StopShellException;
 import at.ac.tuwien.dsg.orvell.annotation.Command;
 import dslab.ComponentFactory;
+import dslab.Email;
+import dslab.Message;
 import dslab.exception.FailedVerificationException;
+import dslab.exception.MalformedInputException;
 import dslab.util.Config;
 
 import javax.crypto.*;
@@ -277,12 +281,13 @@ public class MessageClient implements IMessageClient, Runnable {
 
     /**
      * Generates the full challenge message to be sent to the server.
-     *
+     * <p>
      * The challenge message is of the format:
      * ok <client-challenge> <secret-key> <iv>
      * The parameters are base64 encoded individually, then they are concatenated:
      * ok <base64-client-challenge> <base64-secret-key> <base64-iv>
      * The whole string is then AES encrypted and the result base64 encoded again.
+     *
      * @return A base64 encoded full client challenge.
      */
     private String generateChallengeMessage(PublicKey serverPublicKey) {
@@ -331,11 +336,70 @@ public class MessageClient implements IMessageClient, Runnable {
 
     }
 
+    /**
+     * Pulls a message by id from the MailboxServer and compares the calculated hash against the one received via the
+     * 'hash' field.
+     *
+     * @param id The message id.
+     */
     @Command
     @Override
     public void verify(String id) {
         logger.info("Received 'verify' command for id " + id);
+        Message msg = new Message();
+        String response;
+        // Get message from MailboxServer
+        try {
+            dmapOut.println(getAesCiphertext("show " + id));
+            response = getAesPlaintext(dmapIn.readLine());
+            if (response.startsWith("error")) {
+                this.shell.out().println(response);
+                return;
+            }
+            String[] commands = response.split("\n");
+            if (commands.length != 6) {
+                logger.severe("error expected different message format");
+                return;
+            }
+            msg.setFrom(new Email(commands[0].split("\\s+")[1]));
 
+            String[] addresses = commands[1].split("\\s+")[1].split(",");
+            for (String email : addresses) {
+                msg.addTo(new Email(email));
+            }
+
+            String[] split = commands[2].split("\\s+", 2);
+            msg.setSubject(split.length == 2 ? split[1] : "");
+
+            split = commands[3].split("\\s+", 2);
+            msg.setData(split.length == 2 ? split[1] : "");
+
+            split = commands[4].split("\\s+", 2);
+            msg.setHash(split.length == 2 ? split[1] : "");
+
+            if (!commands[5].startsWith("ok")) {
+                logger.severe("error expected 'ok', got " + commands[5] + " instead");
+            }
+
+            String calculatedHash = msg.calculateHash();
+            logger.info("Calculated hash: " + calculatedHash);
+            if (msg.getHash().equals(calculatedHash)) {
+                this.shell.out().println("ok");
+            } else {
+                this.shell.out().println("error");
+            }
+        } catch (IllegalBlockSizeException | BadPaddingException | NoSuchAlgorithmException | InvalidKeyException e) {
+            logger.severe("Error during encryption/decryption");
+            e.printStackTrace();
+            shutdown();
+        } catch (IOException e) {
+            logger.severe("Cannot communicate with server");
+            e.printStackTrace();
+            shutdown();
+        } catch (MalformedInputException e) {
+            logger.severe("Error during reading of message");
+            e.printStackTrace();
+        }
     }
 
     @Command

src/main/java/dslab/mailbox/DMAPConnection.java

@@ -109,6 +109,8 @@ public class DMAPConnection implements Runnable {
                     if (secure) {
                         out.println(getAesCiphertext("You are already secure!"));
                     } else startSecure();
+                } else if (userInput.startsWith("inbox")) {
+                    printInbox();
                 } else {
                     if (secure) {
                         out.println(getAesCiphertext("error protocol error"));
@@ -130,6 +132,9 @@ public class DMAPConnection implements Runnable {
         }
     }
 
+    private void printInbox() {
+    }
+
     private void loginLoop() {
         String userInput;
 
@@ -330,8 +335,8 @@ public class DMAPConnection implements Runnable {
         for (Message m : storage.get(currentUser)) {
             if (m.getId() == i) {
                 if (secure) {
-                    out.println(getAesCiphertext(m.toString()));
+                    out.println(getAesCiphertext(m.toString() + "ok"));
-                } else out.println(m.toString());
+                } else out.println(m.toString() + "\nok");
                 return;
             }
         }
@@ -349,11 +354,14 @@ public class DMAPConnection implements Runnable {
         }
 
         for (Message m : storage.get(currentUser)) {
-            logger.info("Printing message from user: " + m.listMessage());
+            logger.fine("Printing message from user: " + m.listMessage());
             if (secure) {
                 out.println(getAesCiphertext(m.listMessage()));
             } else out.println(m.listMessage());
         }
+        if (secure) {
+            out.println(getAesCiphertext("ok"));
+        } else out.println("ok");
     }
 
     public void deleteMessage(String id) throws MessageNotFoundException, BadPaddingException, IllegalBlockSizeException {

src/main/java/dslab/mailbox/DMTPConnection.java

@@ -110,6 +110,10 @@ public class DMTPConnection implements Runnable {
                     String data = userInput.split("\\s+", 2)[1];
                     msg.setData(data);
                     out.println("ok");
+                } else if (userInput.startsWith("hash")) {
+                    String hash = userInput.split("\\s+", 2)[1];
+                    msg.setHash(hash);
+                    out.println("ok");
                 } else {
                     out.println("error protocol error");
                     shutdown();

src/main/java/dslab/transfer/ClientConnection.java

@@ -92,6 +92,13 @@ public class ClientConnection implements Runnable {
                     logger.info("Setting data to: " + data);
                     msg.setData(data);
                     out.println("ok");
+                } else if (userInput.startsWith("hash")) {
+                    String hash = "";
+                    if (userInput.split("\\s+", 2).length > 1)
+                        hash = userInput.split("\\s+", 2)[1];
+                    logger.info("Setting hash to: " + hash);
+                    msg.setHash(hash);
+                    out.println("ok");
                 } else {
                     out.println("error protocol error");
                     shutdown();