src/org/ibex/mail/SMTP.java

   1 // Copyright 2000-2005 the Contributors, as shown in the revision logs.
   2 // Licensed under the Apache Public Source License 2.0 ("the License").
   3 // You may not use this file except in compliance with the License.
   4
   5 package org.ibex.mail;
   6 import org.ibex.mail.target.*;
   7 import org.ibex.util.*;
   8 import org.ibex.net.*;
   9 import org.ibex.io.*;
  10 import java.net.*;
  11 import java.io.*;
  12 import java.util.*;
  13 import java.text.*;
  14 import javax.naming.*;
  15 import javax.naming.directory.*;
  16
  17 // RFC's implemented
  18 // RFC2554: SMTP Service Extension for Authentication
  19 //     - did not implement section 5, though
  20 // RFC4616: SASL PLAIN
  21
  22 // Note: we can't actually use status codes for feedback if we accept
  23 // multiple destination addresses...  a failure on one and success on
  24 // the other...
  25
  26 // FIXME: logging: current logging sucks
  27 // FIXME: loop prevention
  28 // FIXME: probably need some throttling on outbound mail
  29
  30 // FEATURE: public static boolean validate(Address a)
  31 // FEATURE: rate-limiting
  32
  33 // FEATURE: infer messageid, date, if not present (?)
  34 // FEATURE: exponential backoff on retry time?
  35 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  36 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  37 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  38 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  39 public class SMTP {
  40
  41     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  42     public static final int numOutgoingThreads = 5;
  43
  44     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  45     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  46
  47     public static final Graylist graylist =
  48         new Graylist(Mailbox.STORAGE_ROOT+"/db/graylist.sqlite");
  49
  50     public static final Whitelist whitelist =
  51         new Whitelist(Mailbox.STORAGE_ROOT+"/db/whitelist.sqlite");
  52
  53     public static final int MAX_MESSAGE_SIZE =
  54         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  55
  56     private static final Mailbox spool =
  57         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true);
  58
  59     static {
  60         for(int i=0; i<numOutgoingThreads; i++)
  61             new Outgoing().start();
  62     }
  63
  64     public static void enqueue(Message m) throws IOException {
  65         if (!m.envelopeTo.isLocal()) Outgoing.enqueue(m);
  66         else                         Target.root.accept(m);
  67     }
  68
  69     public static class SMTPException extends MailException {
  70         int code;
  71         String message;
  72         public SMTPException(String s) {
  73             try {
  74                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  75                 message = s.substring(s.indexOf(' ')+1);
  76             } catch (NumberFormatException nfe) {
  77                 code = -1;
  78                 message = s;
  79             }
  80         }
  81         public String toString() { return "SMTP " + code + ": " + message; }
  82         public String getMessage() { return toString(); }
  83     }
  84
  85     // Server //////////////////////////////////////////////////////////////////////////////
  86
  87     public static class Server {
  88         public void handleRequest(Connection conn) throws IOException {
  89             conn.setTimeout(5 * 60 * 1000);
  90             conn.setNewline("\r\n");
  91             conn.println("220 " + conn.vhost + " ESMTP " + this.getClass().getName());
  92             Address from = null;
  93             Vector to = new Vector();
  94             boolean ehlo = false;
  95             String remotehost = null;
  96             String authenticatedAs = null;
  97             int failedRcptCount = 0;
  98             for(String command = conn.readln(); ; command = conn.readln()) try {
  99                 if (command == null) return;
 100                 Log.warn("**"+conn.getRemoteAddress()+"**", command);
 101                 String c = command.toUpperCase();
 102                 if (c.startsWith("HELO"))        {
 103                     remotehost = c.substring(5).trim();
 104                     conn.println("250 HELO " + conn.vhost);
 105                     from = null; to = new Vector();
 106                 } else if (c.startsWith("EHLO")) {
 107                     remotehost = c.substring(5).trim();
 108                     conn.println("250-"+conn.vhost);
 109                     //conn.println("250-AUTH");
 110                     conn.println("250-AUTH PLAIN");
 111                     //conn.println("250-STARTTLS");
 112                     conn.println("250 HELP");
 113                     ehlo = true;
 114                     from = null; to = new Vector();
 115                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
 116                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
 117                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
 118                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
 119                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 120                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 121                 } else if (c.startsWith("STARTTLS")) {
 122                     conn.println("220 starting TLS...");
 123                     conn.flush();
 124                     conn = conn.negotiateSSL(true);
 125                     from = null; to = new Vector();
 126                 } else if (c.startsWith("AUTH")) {
 127                     if (authenticatedAs != null) {
 128                         conn.println("503 you are already authenticated; you must reconnect to reauth");
 129                     } else {
 130                         String mechanism = command.substring(4).trim();
 131                         String rest = "";
 132                         if (mechanism.indexOf(' ')!=-1) {
 133                             rest      = mechanism.substring(mechanism.indexOf(' ')+1).trim();
 134                             mechanism = mechanism.substring(0, mechanism.indexOf(' '));
 135                         }
 136                         if (mechanism.equals("PLAIN")) {
 137                             // 538 Encryption required for requested authentication mechanism?
 138                             byte[] bytes = Encode.fromBase64(rest);
 139                             String authenticateUser = null;
 140                             String authorizeUser = null;
 141                             String password = null;
 142                             int start = 0;
 143                             for(int i=0; i<=bytes.length; i++) {
 144                                 if (i<bytes.length && bytes[i]!=0) continue;
 145                                 String result = new String(bytes, start, i-start, "UTF-8");
 146                                 if (authenticateUser==null)   authenticateUser = result;
 147                                 else if (authorizeUser==null) authorizeUser = result;
 148                                 else if (password==null)      password = result;
 149                                 start = i+1;
 150                             }
 151                             // FIXME: be smarter here
 152                             if (Main.auth.login(authorizeUser, password)!=null)
 153                                 authenticatedAs = authenticateUser;
 154                             conn.println("235 Authentication successful");
 155                             /*
 156                         } else if (mechanism.equals("CRAM-MD5")) {
 157                             String challenge = ;
 158                             conn.println("334 "+challenge);
 159                             String resp = conn.readln();
 160                             if (resp.equals("*")) {
 161                                 conn.println("501 client requested AUTH cancellation");
 162                             }
 163                         } else if (mechanism.equals("ANONYMOUS")) {
 164                         } else if (mechanism.equals("EXTERNAL")) {
 165                         } else if (mechanism.equals("DIGEST-MD5")) {
 166                             */
 167                         } else {
 168                             conn.println("504 unrecognized authentication type");
 169                         }
 170                         // on success, reset to initial state; client will EHLO again
 171                         from = null; to = new Vector();
 172                     }
 173                 } else if (c.startsWith("MAIL FROM:")) {
 174                     command = command.substring(10).trim();
 175                     from = command.equals("<>") ? null : new Address(command);
 176                     conn.println("250 " + from + " is syntactically correct");
 177                 } else if (c.startsWith("RCPT TO:")) {
 178                     // some clients are broken and put RCPT first; we will tolerate this
 179                     command = command.substring(8).trim();
 180                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 181                     Address addr = new Address(command);
 182                     if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 183                         conn.println("250 you are connected locally, so I will let you send");
 184                         to.addElement(addr);
 185                         if (!whitelist.isWhitelisted(addr))
 186                             whitelist.addWhitelist(addr);
 187                     } else if (authenticatedAs!=null) {
 188                         conn.println("250 you are authenticated as "+authenticatedAs+", so I will let you send");
 189                         to.addElement(addr);
 190                         if (!whitelist.isWhitelisted(addr))
 191                             whitelist.addWhitelist(addr);
 192                     } else if (addr.isLocal()) {
 193                         if (to.size() > 3) {
 194                             conn.println("536 sorry, limit on 3 RCPT TO's per DATA");
 195                         } else {
 196                             // FEATURE: should check the address further and give 550 if undeliverable
 197                             conn.println("250 " + addr + " is on this machine; I will deliver it");
 198                             to.addElement(addr);
 199                         }
 200                     } else {
 201                         conn.println("535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 202                         Log.warn("","535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 203                         failedRcptCount++;
 204                         if (failedRcptCount > 3) {
 205                             conn.close();
 206                             return;
 207                         }
 208                     }
 209                     conn.flush();
 210                 } else if (c.startsWith("DATA")) {
 211                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 212                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 213                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress() && authenticatedAs==null) {
 214                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 215                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 216                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 217                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 218                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 219                             conn.flush();
 220                             continue;
 221                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 222                             graylist.addWhitelist(conn.getRemoteAddress());
 223                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 224                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 225                         } else {
 226                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 227                             conn.flush();
 228                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 229                             continue;
 230                         }
 231                     } else {
 232                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 233                     }
 234                     conn.flush();
 235                     try {
 236                         // FIXME: deal with messages larger than memory here?
 237                         StringBuffer buf = new StringBuffer();
 238                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 239                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 240                         buf.append("          for ");
 241                         // FIXME: this is leaking BCC addrs
 242                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 243                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 244
 245                         // FIXME: some sort of stream transformer here?
 246                         while(true) {
 247                             String s = conn.readln();
 248                             if (s == null) throw new RuntimeException("connection closed");
 249                             if (s.equals(".")) break;
 250                             if (s.startsWith(".")) s = s.substring(1);
 251                             buf.append(s + "\r\n");
 252                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE) {
 253                                 Log.error("**"+conn.getRemoteAddress()+"**",
 254                                           "sorry, this mail server only accepts messages of less than " +
 255                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 256                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 257                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 258                             }
 259                         }
 260                         String body = buf.toString();
 261                         Message m = null;
 262                         for(int i=0; i<to.size(); i++) {
 263                             m = Message.newMessage(Fountain.Util.create(body), from, (Address)to.elementAt(i));
 264                             enqueue(m);
 265                         }
 266                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 267                         conn.println("250 message accepted");
 268                         conn.flush();
 269                         from = null; to = new Vector();
 270                     } catch (MailException.Malformed mfe) {    conn.println("501 " + mfe.toString());
 271                     } catch (MailException.MailboxFull mbf) {  conn.println("452 " + mbf);
 272                     } catch (Script.Later.LaterException le) { conn.println("453 try again later");
 273                     } catch (Script.Reject.RejectException re) {
 274                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 275                         conn.println("501 " + re.reason);
 276                     }
 277                 } else                    { conn.println("500 unrecognized command"); }
 278             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 279         }
 280     }
 281
 282
 283     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 284
 285     public static class Outgoing extends Thread {
 286
 287         private static final HashMap deadHosts = new HashMap();
 288         public static void enqueue(Message m) throws IOException {
 289             if (m == null) { Log.warn(Outgoing.class, "attempted to enqueue(null)"); return; }
 290             String traces = m.headers.get("Received");
 291             if (traces!=null) {
 292                 int lines = 0;
 293                 for(int i=0; i<traces.length(); i++)
 294                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 295                         lines++;
 296                 if (lines > 100) { // required by rfc
 297                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 298                     return;
 299                 }
 300             }
 301             synchronized(Outgoing.class) {
 302                 spool.insert(m, Mailbox.Flag.defaultFlags);
 303                 Outgoing.class.notifyAll();
 304             }
 305         }
 306
 307         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 308         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 309             if (m.envelopeTo == null) {
 310                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 311                 return false;
 312             }
 313             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 314             if (mx.length == 0) {
 315                 if (!noBounces) {
 316                     enqueue(m.bounce("could not resolve " + m.envelopeTo.host));
 317                     return true;
 318                 } else {
 319                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 320                     return false;
 321                 }
 322             }
 323             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 324                 if (!noBounces) {
 325                     enqueue(m.bounce("could not send for 5 days"));
 326                     return true;
 327                 } else {
 328                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 329                     return false;
 330                 }
 331             }
 332             for(int i=0; i<mx.length; i++) {
 333                 //if (deadHosts.contains(mx[i])) continue;
 334                 if (attempt(m, mx[i])) { return true; }
 335             }
 336             return false;
 337         }
 338
 339         private static void check(String s, Connection conn) {
 340             if (s==null) return;
 341             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 342             //if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 343             if (!s.startsWith("2")&&!s.startsWith("3")) throw new SMTPException(s);
 344         }
 345         private static boolean attempt(final Message m, final InetAddress mx) {
 346             boolean accepted = false;
 347             Connection conn = null;
 348             try {
 349                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 350                 conn.setNewline("\r\n");
 351                 conn.setTimeout(60 * 1000);
 352                 check(conn.readln(), conn);  // banner
 353                 try {
 354                     conn.println("EHLO " + conn.vhost);
 355                     check(conn.readln(), conn);
 356                 } catch (SMTPException smtpe) {
 357                     conn.println("HELO " + conn.vhost);
 358                     check(conn.readln(), conn);
 359                 }
 360                 String envelopeFrom = m.envelopeFrom==null ? "" : m.envelopeFrom.toString();
 361                 conn.println("MAIL FROM:<" + envelopeFrom +">");            check(conn.readln(), conn);
 362                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");  check(conn.readln(), conn);
 363                 conn.println("DATA");                                       check(conn.readln(), conn);
 364
 365                 Headers head = new Headers(m.headers,
 366                                            new String[] {
 367                                                "return-path", null,
 368                                                "bcc", null
 369                                            });
 370                 Stream stream = head.getStream();
 371                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 372                     if (s.startsWith(".")) conn.print(".");
 373                     conn.println(s);
 374                 }
 375                 conn.println("");
 376                 stream = m.getBody().getStream();
 377                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 378                     if (s.startsWith(".")) conn.print(".");
 379                     conn.println(s);
 380                 }
 381                 conn.println(".");
 382                 String resp = conn.readln();
 383                 if (resp == null)
 384                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 385                 check(resp, conn);
 386                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 387                 accepted = true;
 388                 conn.close();
 389             } catch (SMTPException e) {
 390                 if (accepted) return true;
 391                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 392                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 393                 Log.warn(SMTP.Outgoing.class, e);
 394                 if (e.code >= 500 && e.code <= 599) {
 395                     try {
 396                         attempt(m.bounce("unable to deliver: " + e), true);
 397                     } catch (Exception ex) {
 398                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 399                         Log.error(SMTP.Outgoing.class, ex);
 400                     }
 401                     return true;
 402                 }
 403                 return false;
 404             } catch (Exception e) {
 405                 if (accepted) return true;
 406                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 407                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 408                 Log.warn(SMTP.Outgoing.class, e);
 409                 if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 410                 return false;
 411             } finally {
 412                 if (conn != null) conn.close();
 413             }
 414             return accepted;
 415         }
 416
 417         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 418         private static int serials = 1;
 419         private int serial = serials++;
 420         private Mailbox.Iterator it;
 421
 422         public Outgoing() {
 423             synchronized(Outgoing.class) {
 424                 threads.add(this);
 425             }
 426         }
 427
 428         public void wake() {
 429             int count = spool.count(Query.all());
 430             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 431             try {
 432                 while(true) {
 433                     boolean good = false;
 434                     synchronized(Outgoing.class) {
 435                         it = spool.iterator();
 436                         OUTER: for(; it.next(); ) {
 437                             for(Outgoing o : threads)
 438                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 439                                     continue OUTER;
 440                             good = true;
 441                             break;
 442                         }
 443                     }
 444                     if (!good) break;
 445                     try {
 446                         if (attempt(it.cur())) it.delete();
 447                     } catch (Exception e) {
 448                         Log.error(SMTP.Outgoing.class, e);
 449                     }
 450                     Log.info(this, "sleeping for 3s...");
 451                     Thread.sleep(3000);
 452                 }
 453             } catch (Exception e) {
 454                 //if (e instanceof InterruptedException) throw e;
 455                 Log.error(SMTP.Outgoing.class, e);
 456             }
 457             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 458             it = null;
 459         }
 460
 461         public void run() {
 462             try {
 463                 while(true) {
 464                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 465                     wake();
 466                     Thread.sleep(1000);
 467                     synchronized(Outgoing.class) {
 468                         Outgoing.class.wait(5 * 60 * 1000);
 469                     }
 470                 }
 471             } catch (InterruptedException e) { Log.warn(this, e); }
 472         }
 473     }
 474
 475     public static InetAddress[] getMailExchangerIPs(String hostName) {
 476         InetAddress[] ret;
 477         try {
 478             Hashtable env = new Hashtable();
 479             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 480             DirContext ictx = new InitialDirContext(env);
 481             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 482             Attribute attr = attrs.get("MX");
 483             if (attr == null) {
 484                 ret = new InetAddress[1];
 485                 try {
 486                     ret[0] = InetAddress.getByName(hostName);
 487                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 488                     return ret;
 489                 } catch (UnknownHostException uhe) {
 490                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 491                     return new InetAddress[0];
 492                 }
 493             } else {
 494                 ret = new InetAddress[attr.size()];
 495                 NamingEnumeration ne = attr.getAll();
 496                 for(int i=0; ne.hasMore();) {
 497                     String mx = (String)ne.next();
 498                     // FIXME we should be sorting here
 499                     mx = mx.substring(mx.indexOf(" ") + 1);
 500                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 501                     InetAddress ia = InetAddress.getByName(mx);
 502                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 503                     ret[i++] = ia;
 504                 }
 505             }
 506         } catch (Exception e) {
 507             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 508             Log.warn(SMTP.class, e);
 509             return new InetAddress[0];
 510         }
 511         return ret;
 512     }
 513 }