IRC Server: Better timeout handling when reading initial lines (ticket #723)

Send error responses for timeout, EOF, and bad registration.
Only affects "user" mode, not webirc.
detab
move private fields to top

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/I2PTunnelIRCServer.java

@@ -1,17 +1,18 @@
 package net.i2p.i2ptunnel;
 
+import java.io.EOFException;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.InetAddress;
 import java.net.Socket;
 import java.net.SocketException;
+import java.net.SocketTimeoutException;
 import java.util.Locale;
 import java.util.Properties;
 
 import net.i2p.client.streaming.I2PSocket;
 import net.i2p.crypto.SHA256Generator;
-import net.i2p.data.DataHelper;
 import net.i2p.data.Destination;
 import net.i2p.data.Hash;
 import net.i2p.data.Base32;
@@ -54,23 +55,44 @@ import net.i2p.util.Log;
  * @author zzz
  */
 public class I2PTunnelIRCServer extends I2PTunnelServer implements Runnable {
+    private final byte[] cloakKey; // 32 bytes of stuff to scramble the dest with
+    private final String hostname;
+    private final String method;
+    private final String webircPassword;
+    private final String webircSpoofIP;
+
     public static final String PROP_METHOD="ircserver.method";
     public static final String PROP_METHOD_DEFAULT="user";
     public static final String PROP_CLOAK="ircserver.cloakKey";
     public static final String PROP_WEBIRC_PASSWORD="ircserver.webircPassword";
-	public static final String PROP_WEBIRC_SPOOF_IP="ircserver.webircSpoofIP";
+    public static final String PROP_WEBIRC_SPOOF_IP="ircserver.webircSpoofIP";
-	public static final String PROP_WEBIRC_SPOOF_IP_DEFAULT="127.0.0.1";
+    public static final String PROP_WEBIRC_SPOOF_IP_DEFAULT="127.0.0.1";
     public static final String PROP_HOSTNAME="ircserver.fakeHostname";
     public static final String PROP_HOSTNAME_DEFAULT="%f.b32.i2p";
     private static final long HEADER_TIMEOUT = 15*1000;
     private static final long TOTAL_HEADER_TIMEOUT = 2 * HEADER_TIMEOUT;
+    private static final int MAX_LINE_LENGTH = 1024;
     
-    private final static byte[] ERR_UNAVAILABLE =
+    private final static String ERR_UNAVAILABLE =
-        (":ircserver.i2p 499 you :" +
+        ":ircserver.i2p 499 you :" +
          "This I2P IRC server is unavailable. It may be down or undergoing maintenance. " +
          "Please try again later." +
-         "\r\n")
+         "\r\n";
-         .getBytes();
+
+    private final static String ERR_REGISTRATION =
+        ":ircserver.i2p 499 you :" +
+         "Bad registration." +
+         "\r\n";
+
+    private final static String ERR_TIMEOUT =
+        ":ircserver.i2p 499 you :" +
+         "Timeout registering." +
+         "\r\n";
+
+    private final static String ERR_EOF =
+        ":ircserver.i2p 499 you :" +
+         "EOF while registering." +
+         "\r\n";
 
     private static final String[] BAD_PROTOCOLS = {
         "GET ", "HEAD ", "POST ", "GNUTELLA CONNECT", "\023BitTorrent protocol"
@@ -97,8 +119,8 @@ public class I2PTunnelIRCServer extends I2PTunnelServer implements Runnable {
         // get the password for the webirc method
         this.webircPassword = opts.getProperty(PROP_WEBIRC_PASSWORD);
 
-		// get the spoof IP for the webirc method
+        // get the spoof IP for the webirc method
-		this.webircSpoofIP = opts.getProperty(PROP_WEBIRC_SPOOF_IP, PROP_WEBIRC_SPOOF_IP_DEFAULT);
+        this.webircSpoofIP = opts.getProperty(PROP_WEBIRC_SPOOF_IP, PROP_WEBIRC_SPOOF_IP_DEFAULT);
         
         // get the cloaking passphrase
         String passphrase = opts.getProperty(PROP_CLOAK);
@@ -119,35 +141,66 @@ public class I2PTunnelIRCServer extends I2PTunnelServer implements Runnable {
             _log.info("Incoming connection to '" + toString() + "' port " + socket.getLocalPort() +
                       " from: " + socket.getPeerDestination().calculateHash() + " port " + socket.getPort());
         try {
-			String modifiedRegistration;
+            String modifiedRegistration;
-			if(!this.method.equals("webirc")) {
+            if(!this.method.equals("webirc")) {
-				// The headers _should_ be in the first packet, but
+                // The headers _should_ be in the first packet, but
-				// may not be, depending on the client-side options
+                // may not be, depending on the client-side options
-				socket.setReadTimeout(HEADER_TIMEOUT);
+                modifiedRegistration = filterRegistration(socket, cloakDest(socket.getPeerDestination()));
-				InputStream in = socket.getInputStream();
+                socket.setReadTimeout(readTimeout);
-				modifiedRegistration = filterRegistration(in, cloakDest(socket.getPeerDestination()));
+            } else {
-				socket.setReadTimeout(readTimeout);
+                StringBuffer buf = new StringBuffer("WEBIRC ");
-			} else {
+                buf.append(this.webircPassword);
-				StringBuffer buf = new StringBuffer("WEBIRC ");
+                buf.append(" cgiirc ");
-				buf.append(this.webircPassword);
+                buf.append(cloakDest(socket.getPeerDestination()));
-				buf.append(" cgiirc ");
+                buf.append(' ');
-				buf.append(cloakDest(socket.getPeerDestination()));
+                buf.append(this.webircSpoofIP);
-				buf.append(' ');
+                buf.append("\r\n");
-				buf.append(this.webircSpoofIP);
+                modifiedRegistration = buf.toString();
-				buf.append("\r\n");
+            }
-				modifiedRegistration = buf.toString();
-			}
             Socket s = getSocket(socket.getPeerDestination().calculateHash(), socket.getLocalPort());
             Thread t = new I2PTunnelRunner(s, socket, slock, null, modifiedRegistration.getBytes(),
                                            null, (I2PTunnelRunner.FailCallback) null);
             // run in the unlimited client pool
             //t.start();
             _clientExecutor.execute(t);
+        } catch (RegistrationException ex) {
+            try {
+                // Send a response so the user doesn't just see a disconnect
+                // and blame his router or the network.
+                socket.getOutputStream().write(ERR_REGISTRATION.getBytes("ISO-8859-1"));
+            } catch (IOException ioe) {
+            } finally {
+                 try { socket.close(); } catch (IOException ioe) {}
+            }
+            if (_log.shouldLog(Log.WARN))
+                _log.warn("Error while receiving the new IRC Connection", ex);
+        } catch (EOFException ex) {
+            try {
+                // Send a response so the user doesn't just see a disconnect
+                // and blame his router or the network.
+                socket.getOutputStream().write(ERR_EOF.getBytes("ISO-8859-1"));
+            } catch (IOException ioe) {
+            } finally {
+                 try { socket.close(); } catch (IOException ioe) {}
+            }
+            if (_log.shouldLog(Log.WARN))
+                _log.warn("Error while receiving the new IRC Connection", ex);
+        } catch (SocketTimeoutException ex) {
+            try {
+                // Send a response so the user doesn't just see a disconnect
+                // and blame his router or the network.
+                socket.getOutputStream().write(ERR_TIMEOUT.getBytes("ISO-8859-1"));
+            } catch (IOException ioe) {
+            } finally {
+                 try { socket.close(); } catch (IOException ioe) {}
+            }
+            if (_log.shouldLog(Log.WARN))
+                _log.warn("Error while receiving the new IRC Connection", ex);
         } catch (SocketException ex) {
             try {
                 // Send a response so the user doesn't just see a disconnect
                 // and blame his router or the network.
-                socket.getOutputStream().write(ERR_UNAVAILABLE);
+                socket.getOutputStream().write(ERR_UNAVAILABLE.getBytes("ISO-8859-1"));
             } catch (IOException ioe) {}
             try {
                 socket.close();
@@ -191,27 +244,35 @@ public class I2PTunnelIRCServer extends I2PTunnelServer implements Runnable {
         return this.hostname.replace("%f", hf).replace("%c", hc);
     }
 
-    /** keep reading until we see USER or SERVER */
+    /**
-    private static String filterRegistration(InputStream in, String newHostname) throws IOException {
+     *  Keep reading until we see USER or SERVER.
+     *  This modifies the socket readTimeout, caller must save and restore.
+     *
+     *  @throws SocketTimeoutException if timeout is reached before newline
+     *  @throws EOFException if EOF is reached before newline
+     *  @throws RegistrationException if line too long
+     *  @throws IOException on other errors in the underlying stream
+     */
+    private static String filterRegistration(I2PSocket socket, String newHostname) throws IOException {
         StringBuilder buf = new StringBuilder(128);
         int lineCount = 0;
         
         // slowloris / darkloris
         long expire = System.currentTimeMillis() + TOTAL_HEADER_TIMEOUT;
         while (true) {
-            String s = DataHelper.readLine(in);
+            String s = readLine(socket, expire - System.currentTimeMillis());
             if (s == null)
-                throw new IOException("EOF reached before the end of the headers [" + buf.toString() + "]");
+                throw new EOFException("EOF reached before the end of the headers");
             if (lineCount == 0) {
                 for (int i = 0; i < BAD_PROTOCOLS.length; i++) {
                     if (s.startsWith(BAD_PROTOCOLS[i]))
-                        throw new IOException("Bad protocol " + BAD_PROTOCOLS[i]);
+                        throw new RegistrationException("Bad protocol " + BAD_PROTOCOLS[i]);
                 }
             }
             if (++lineCount > 10)
-                throw new IOException("Too many lines before USER or SERVER, giving up");
+                throw new RegistrationException("Too many lines before USER or SERVER, giving up");
             if (System.currentTimeMillis() > expire)
-                throw new IOException("Headers took too long [" + buf.toString() + "]");
+                throw new SocketTimeoutException("Headers took too long");
             s = s.trim();
             //if (_log.shouldLog(Log.DEBUG))
             //    _log.debug("Got line: " + s);
@@ -225,12 +286,12 @@ public class I2PTunnelIRCServer extends I2PTunnelServer implements Runnable {
                     idx++;
                 command = field[idx++].toUpperCase(Locale.US);
             } catch (IndexOutOfBoundsException ioobe) {
-                throw new IOException("Dropping defective message: [" + s + ']');
+                throw new RegistrationException("Dropping defective message: [" + s + ']');
             }
 
             if ("USER".equals(command)) {
                 if (field.length < idx + 4)
-                    throw new IOException("Too few parameters in USER message: " + s);
+                    throw new RegistrationException("Too few parameters in USER message: " + s);
                 // USER zzz1 hostname localhost :zzz
                 //  =>
                 // USER zzz1 abcd1234.i2p localhost :zzz
@@ -249,9 +310,58 @@ public class I2PTunnelIRCServer extends I2PTunnelServer implements Runnable {
         return buf.toString();
     }
     
-    private final byte[] cloakKey; // 32 bytes of stuff to scramble the dest with
+    /**
-    private final String hostname;
+     *  Read a line teriminated by newline, with a total read timeout.
-    private final String method;
+     *
-    private final String webircPassword;
+     *  Warning - strips \n but not \r
-    private final String webircSpoofIP;
+     *  Warning - 8KB line length limit as of 0.7.13, @throws IOException if exceeded
+     *  Warning - not UTF-8
+     *
+     *  @param timeout throws SocketTimeoutException immediately if zero or negative
+     *  @throws SocketTimeoutException if timeout is reached before newline
+     *  @throws EOFException if EOF is reached before newline
+     *  @throws RegistrationException if line too long
+     *  @throws IOException on other errors in the underlying stream
+     *  @since 0.9.19 modified from DataHelper and I2PTunnelHTTPServer
+     */
+    private static String readLine(I2PSocket socket, long timeout) throws IOException {
+        StringBuilder buf = new StringBuilder(128);
+        if (timeout <= 0)
+            throw new SocketTimeoutException();
+        long expires = System.currentTimeMillis() + timeout;
+        InputStream in = socket.getInputStream();
+        int c;
+        int i = 0;
+        socket.setReadTimeout(timeout);
+        while ( (c = in.read()) != -1) {
+            if (++i > MAX_LINE_LENGTH)
+                throw new RegistrationException("Line too long - max " + MAX_LINE_LENGTH);
+            if (c == '\n')
+                break;
+            long newTimeout = expires - System.currentTimeMillis();
+            if (newTimeout <= 0)
+                throw new SocketTimeoutException();
+            buf.append((char)c);
+            if (newTimeout != timeout) {
+                timeout = newTimeout;
+                socket.setReadTimeout(timeout);
+            }
+        }
+        if (c == -1) {
+            if (System.currentTimeMillis() >= expires)
+                throw new SocketTimeoutException();
+            else
+                throw new EOFException();
+        }
+        return buf.toString();
+    }
+
+    /**
+     *  @since 0.9.19
+     */
+    private static class RegistrationException extends IOException {
+        public RegistrationException(String s) {
+            super(s);
+        }
+    }
 }

history.txt

@@ -1,3 +1,6 @@
+2015-04-05 zzz
+ * IRC Server: Better timeout handling reading initial lines (ticket #723)
+
 2015-04-04 zzz
  * i2ptunnel:
    - Better timeout handling when reading headers in HTTP server (ticket #723)

router/java/src/net/i2p/router/RouterVersion.java

@@ -18,7 +18,7 @@ public class RouterVersion {
     /** deprecated */
     public final static String ID = "Monotone";
     public final static String VERSION = CoreVersion.VERSION;
-    public final static long BUILD = 17;
+    public final static long BUILD = 18;
 
     /** for example "-test" */
     public final static String EXTRA = "-rc";