Support for POP3 SASL Plain (fixes #301)

greenmail-mail-test · Apr 3, 2020 · 14ad55b · 14ad55b
1 parent 7d177fd
commit 14ad55b
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Showing 9 changed files with 261 additions and 35 deletions.
diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/Pop3Handler.java b/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/Pop3Handler.java
@@ -6,20 +6,21 @@
  */
 package com.icegreen.greenmail.pop3;
 
+import java.io.IOException;
+import java.net.Socket;
+import java.net.SocketTimeoutException;
+import java.util.StringTokenizer;
 
 import com.icegreen.greenmail.pop3.commands.Pop3Command;
 import com.icegreen.greenmail.pop3.commands.Pop3CommandRegistry;
 import com.icegreen.greenmail.server.BuildInfo;
 import com.icegreen.greenmail.server.ProtocolHandler;
 import com.icegreen.greenmail.user.UserManager;
-
-import java.io.IOException;
-import java.net.Socket;
-import java.net.SocketTimeoutException;
-import java.util.StringTokenizer;
-
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class Pop3Handler implements ProtocolHandler {
+    protected final Logger log = LoggerFactory.getLogger(getClass());
     Pop3CommandRegistry registry;
     Pop3Connection conn;
     UserManager manager;
@@ -52,12 +53,16 @@ public void run() {
             conn.close();
         } catch (SocketTimeoutException ste) {
             conn.println("421 Service shutting down and closing transmission channel");
-
         } catch (Exception e) {
+            if (!quitting) {
+                log.error("Can not handle POP3 connection", e);
+                throw new IllegalStateException("Can not handle POP3 connection", e);
+            }
         } finally {
             try {
                 socket.close();
             } catch (IOException ioe) {
+                // Nothing
             }
         }
 
@@ -77,20 +82,17 @@ void handleCommand()
             return;
         }
 
-        String commandName = new StringTokenizer(currentLine, " ").nextToken()
-                .toUpperCase();
+        String commandName = new StringTokenizer(currentLine, " ").nextToken().toUpperCase();
 
         Pop3Command command = registry.getCommand(commandName);
 
         if (command == null) {
             conn.println("-ERR Command not recognized");
-
             return;
         }
 
         if (!command.isValidForState(state)) {
             conn.println("-ERR Command not valid for this state");
-
             return;
         }
 
@@ -99,12 +101,12 @@ void handleCommand()
 
     @Override
     public void close() {
-         quitting = true;
+        quitting = true;
         try {
             if (socket != null && !socket.isClosed()) {
                 socket.close();
             }
-        } catch(IOException ignored) {
+        } catch (IOException ignored) {
             //empty
         }
     }

diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/Pop3State.java b/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/Pop3State.java
@@ -34,7 +34,7 @@ public GreenMailUser getUser() {
     public GreenMailUser getUser(String username) throws UserException {
         GreenMailUser user = manager.getUser(username);
         if (null == user) {
-            throw new NoSuchUserException(username + " doesn't exist");
+            throw new NoSuchUserException("User <" + username + "> doesn't exist");
         }
         return user;
     }
@@ -57,7 +57,6 @@ public void authenticate(String pass)
     }
 
     public MailFolder getFolder() {
-
         return inbox;
     }
 }
diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/AuthCommand.java b/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/AuthCommand.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2014 Wael Chatila / Icegreen Technologies. All Rights Reserved.
+ * This software is released under the Apache license 2.0
+ * This file has been used and modified.
+ * Original file can be found on http://foedus.sourceforge.net
+ */
+package com.icegreen.greenmail.pop3.commands;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+
+import com.icegreen.greenmail.pop3.Pop3Connection;
+import com.icegreen.greenmail.pop3.Pop3State;
+import com.icegreen.greenmail.store.FolderException;
+import com.icegreen.greenmail.user.GreenMailUser;
+import com.icegreen.greenmail.user.UserException;
+import com.icegreen.greenmail.util.EncodingUtil;
+import com.sun.mail.util.BASE64DecoderStream;
+
+/**
+ * SASL : PLAIN
+ * <p>
+ * https://tools.ietf.org/html/rfc5034
+ * <p>
+ * AUTH mechanism [initial-response]
+ * mechanism PLAIN : See https://tools.ietf.org/html/rfc4616
+ */
+public class AuthCommand
+        extends Pop3Command {
+
+    public static final String CONTINUATION = "+ ";
+
+    @Override
+    public boolean isValidForState(Pop3State state) {
+
+        return !state.isAuthenticated();
+    }
+
+    public enum Pop3SaslAuthMechanism {
+        PLAIN;
+
+        /**
+         * WS separated list of supported auth mechanism.
+         *
+         * @return a list of supported auth mechanism.
+         */
+        static String list() {
+            StringBuilder buf = new StringBuilder();
+            for (Pop3SaslAuthMechanism mechanism : values()) {
+                if (buf.length() > 0) {
+                    buf.append(' ');
+                }
+                buf.append(mechanism.name());
+            }
+            return buf.toString();
+        }
+    }
+
+    @Override
+    public void execute(Pop3Connection conn, Pop3State state, String cmd) {
+        if (state.isAuthenticated()) {
+            conn.println("-ERR Already authenticated");
+            return;
+        }
+
+        String[] args = cmd.split(" ");
+        if (args.length < 2) {
+            conn.println("-ERR Required syntax: AUTH mechanism [initial-response]");
+            return;
+        }
+
+        String mechanism = args[1];
+        if (Pop3SaslAuthMechanism.PLAIN.name().equalsIgnoreCase(mechanism)) {
+            authPlain(conn, state, args);
+        } else {
+            conn.println("-ERR Required syntax: AUTH mechanism <" + mechanism +
+                    "> not supported, expected one of " + Arrays.toString(Pop3SaslAuthMechanism.values()));
+        }
+    }
+
+    private void authPlain(Pop3Connection conn, Pop3State state, String[] args) {
+        // https://tools.ietf.org/html/rfc4616
+        String initialResponse;
+        if (args.length == 2 || args.length == 3 && "=".equals(args[2])) { // Continuation?
+            conn.println(CONTINUATION);
+            try {
+                initialResponse = conn.readLine();
+            } catch (IOException e) {
+                conn.println("-ERR Invalid syntax, expected continuation with iniital-response");
+                return;
+            }
+        } else if (args.length == 3) {
+            initialResponse = args[2];
+        } else {
+            conn.println("-ERR Invalid syntax, expected initial-response : AUTH PLAIN [initial-response]");
+            return;
+        }
+
+        // authorization-id\0authentication-id\0passwd
+        final BASE64DecoderStream stream = new BASE64DecoderStream(
+                new ByteArrayInputStream(initialResponse.getBytes(StandardCharsets.UTF_8)));
+        readTillNullChar(stream); // authorizationId Not used
+        String authenticationId = readTillNullChar(stream);
+
+        GreenMailUser user;
+        try {
+            user = state.getUser(authenticationId);
+            state.setUser(user);
+        } catch (UserException e) {
+            log.error("Can not get user <" + authenticationId + ">", e);
+            conn.println("-ERR Authentication failed: " + e.getMessage() /* GreenMail is just a test server */);
+            return;
+        }
+
+        try {
+            state.authenticate(readTillNullChar(stream));
+            conn.println("+OK");
+        } catch (UserException e) {
+            log.error("Can not authenticate using user <" + user.getLogin() + ">", e);
+            conn.println("-ERR Authentication failed: " + e.getMessage());
+        } catch (FolderException e) {
+            log.error("Can not authenticate using user " + user + ", internal error", e);
+            conn.println("-ERR Authentication failed, internal error: " + e.getMessage());
+        }
+    }
+
+
+    @Deprecated // Remove once JDK baseline is 1.8
+    private String readTillNullChar(BASE64DecoderStream stream) {
+        try {
+            return EncodingUtil.readTillNullChar(stream);
+        } catch (IOException e) {
+            log.error("Can not decode", e);
+            return null;
+        }
+    }
+}
diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/CapaCommand.java b/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/CapaCommand.java
@@ -37,6 +37,7 @@ public void execute(Pop3Connection conn, Pop3State state, String cmd) {
         // We don't support any additional capabilities
         conn.println("+OK");
         conn.println("UIDL");
+        conn.println("SASL "+ AuthCommand.Pop3SaslAuthMechanism.list());
         conn.println(".");
     }
 }
diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/Pop3Command.java b/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/Pop3Command.java
@@ -8,9 +8,13 @@
 
 import com.icegreen.greenmail.pop3.Pop3Connection;
 import com.icegreen.greenmail.pop3.Pop3State;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 
 public abstract class Pop3Command {
+    protected final Logger log = LoggerFactory.getLogger(getClass());
+
     public abstract boolean isValidForState(Pop3State state);
 
     public abstract void execute(Pop3Connection conn, Pop3State state,

diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/Pop3CommandRegistry.java b/greenmail-core/src/main/java/com/icegreen/greenmail/pop3/commands/Pop3CommandRegistry.java
@@ -27,6 +27,7 @@ public class Pop3CommandRegistry {
         commands.put("NOOP", new NoopCommand());
         commands.put("RSET", new RsetCommand());
         commands.put("CAPA", new CapaCommand());
+        commands.put("AUTH", new AuthCommand());
     }
 
     public Pop3Command getCommand(String name) {

diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/smtp/commands/AuthCommand.java b/greenmail-core/src/main/java/com/icegreen/greenmail/smtp/commands/AuthCommand.java
@@ -75,8 +75,6 @@ public void execute(SmtpConnection conn, SmtpState state,
     }
 
     private void authPlain(SmtpConnection conn, SmtpManager manager, String[] commandParts) throws IOException {
-        AuthMechanism authMechanism = AuthMechanism.PLAIN;
-
         // Continuation?
         String initialResponse;
         if (commandParts.length == 2) {
@@ -86,7 +84,7 @@ private void authPlain(SmtpConnection conn, SmtpManager manager, String[] comman
             initialResponse = commandParts[2];
         }
 
-        if (authenticate(manager.getUserManager(), authMechanism, initialResponse)) {
+        if (authenticate(manager.getUserManager(), initialResponse)) {
             conn.setAuthenticated(true);
             conn.send(AUTH_SUCCEDED);
         } else {
@@ -114,27 +112,20 @@ private void authLogin(SmtpConnection conn, SmtpManager manager, String commandL
         }
     }
 
-    private boolean authenticate(UserManager userManager, AuthMechanism authMechanism, String value) {
-        if (AuthMechanism.PLAIN == authMechanism) {
-            // authorization-id\0authentication-id\0passwd
-            final BASE64DecoderStream stream = new BASE64DecoderStream(
-                    new ByteArrayInputStream(value.getBytes(StandardCharsets.US_ASCII)));
-            readTillNullChar(stream); // authorizationId Not used
-            String authenticationId = readTillNullChar(stream);
-            String passwd = readTillNullChar(stream);
-            return userManager.test(authenticationId, passwd);
-        }
-        return false;
+    private boolean authenticate(UserManager userManager, String value) {
+        // authorization-id\0authentication-id\0passwd
+        final BASE64DecoderStream stream = new BASE64DecoderStream(
+                new ByteArrayInputStream(value.getBytes(StandardCharsets.UTF_8)));
+        readTillNullChar(stream); // authorizationId Not used
+        String authenticationId = readTillNullChar(stream);
+        String passwd = readTillNullChar(stream);
+        return userManager.test(authenticationId, passwd);
     }
 
     @Deprecated // Remove once JDK baseline is 1.8
     private String readTillNullChar(BASE64DecoderStream stream) {
         try {
-            StringBuilder buf = new StringBuilder();
-            for (int chr = stream.read(); chr != '\0' && chr > 0; chr = stream.read()) {
-                buf.append((char) chr);
-            }
-            return buf.toString();
+            return EncodingUtil.readTillNullChar(stream);
         } catch (IOException e) {
             log.error("Can not decode", e);
             return null;
@@ -144,7 +135,7 @@ private String readTillNullChar(BASE64DecoderStream stream) {
     private static String getValuesWsSeparated() {
         StringBuilder buf = new StringBuilder();
         for (AuthMechanism mechanism : AuthMechanism.values()) {
-            if(buf.length()>0) {
+            if (buf.length() > 0) {
                 buf.append(' ');
             }
             buf.append(mechanism);

diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/util/EncodingUtil.java b/greenmail-core/src/main/java/com/icegreen/greenmail/util/EncodingUtil.java
@@ -8,6 +8,8 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Base64;
 
+import com.sun.mail.util.BASE64DecoderStream;
+
 /**
  * Helper for handling encodings.
  */
@@ -60,4 +62,13 @@ public static String toString(InputStream is, Charset charset) {
     public static String decodeBase64(String encoded) {
         return new String(Base64.getDecoder().decode(encoded), StandardCharsets.UTF_8);
     }
+
+    @Deprecated // Remove once JDK baseline is 1.8
+    public static String readTillNullChar(BASE64DecoderStream stream) throws IOException {
+        StringBuilder buf = new StringBuilder();
+        for (int chr = stream.read(); chr != '\u0000' && chr > 0; chr = stream.read()) {
+            buf.append((char) chr);
+        }
+        return buf.toString();
+    }
 }