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
  15 // FIXME: inbound throttling/ratelimiting
  16
  17 // "Address enumeration detection" -- notice when it looks like somebody
  18 // is trying a raft of addresses.
  19
  20 // RFC's implemented
  21 // RFC2554: SMTP Service Extension for Authentication
  22 //     - did not implement section 5, though
  23 // RFC4616: SASL PLAIN
  24
  25 // Note: we can't actually use status codes for feedback if we accept
  26 // multiple destination addresses...  a failure on one and success on
  27 // the other...
  28
  29 // FIXME: logging: current logging sucks
  30 // FIXME: loop prevention
  31 // FIXME: probably need some throttling on outbound mail
  32
  33 // FEATURE: public static boolean validate(Address a)
  34 // FEATURE: rate-limiting
  35
  36 // FEATURE: infer messageid, date, if not present (?)
  37 // FEATURE: exponential backoff on retry time?
  38 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  39 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  40 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  41 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  42 public class SMTP {
  43
  44     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  45     public static final int numOutgoingThreads = 5;
  46
  47     private static final SqliteMailbox allmail =
  48         (SqliteMailbox)FileBasedMailbox
  49         .getFileBasedMailbox("/afs/megacz.com/mail/user/megacz/allmail", false);
  50
  51     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  52     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  53
  54     public static final int RETRY_TIME = 1000 * 60 * 30;
  55
  56     public static final Graylist graylist;
  57     public static final Whitelist whitelist;
  58     static {
  59         try {
  60             graylist =  new Graylist(Mailbox.STORAGE_ROOT+"/db/graylist.sqlite");
  61             whitelist = new Whitelist(Mailbox.STORAGE_ROOT+"/db/whitelist.sqlite");
  62         } catch (Exception e) {
  63             throw new RuntimeException(e);
  64         }
  65     }
  66
  67     public static final int MAX_MESSAGE_SIZE =
  68         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  69
  70     private static final Mailbox spool =
  71         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true).getMailbox();
  72
  73     static {
  74         for(int i=0; i<numOutgoingThreads; i++)
  75             new Outgoing().start();
  76     }
  77
  78     public static void enqueue(Message m) throws IOException {
  79         if (!m.envelopeTo.isLocal()) Outgoing.enqueue(m);
  80         else {
  81             try {
  82                 allmail.accept(m);
  83             } catch (Exception e) {
  84                 // FIXME incredibly gross hack
  85                 if (e.toString().indexOf("attempt to insert two messages with identical messageid")==-1)
  86                     Log.error(SMTP.class, e);
  87             }
  88             Target.root.accept(m);
  89         }
  90     }
  91
  92     public static class SMTPException extends MailException {
  93         int code;
  94         String message;
  95         public SMTPException(String s) {
  96             try {
  97                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  98                 message = s.substring(s.indexOf(' ')+1);
  99             } catch (NumberFormatException nfe) {
 100                 code = -1;
 101                 message = s;
 102             }
 103         }
 104         public String toString() { return "SMTP " + code + ": " + message; }
 105         public String getMessage() { return toString(); }
 106     }
 107
 108     // Server //////////////////////////////////////////////////////////////////////////////
 109
 110     public static class Server {
 111         public void handleRequest(Connection conn) throws IOException {
 112             conn.setTimeout(5 * 60 * 1000);
 113             conn.setNewline("\r\n");
 114             conn.println("220 " + conn.vhost + " ESMTP " + this.getClass().getName());
 115             Address from = null;
 116             Vector to = new Vector();
 117             boolean ehlo = false;
 118             String remotehost = null;
 119             String authenticatedAs = null;
 120             int failedRcptCount = 0;
 121             for(String command = conn.readln(); ; command = conn.readln()) try {
 122                 if (command == null) return;
 123                 Log.warn("**"+conn.getRemoteAddress()+"**", command);
 124                 String c = command.toUpperCase();
 125                 if (c.startsWith("HELO"))        {
 126                     remotehost = c.substring(5).trim();
 127                     conn.println("250 HELO " + conn.vhost);
 128                     from = null; to = new Vector();
 129                 } else if (c.startsWith("EHLO")) {
 130                     remotehost = c.substring(5).trim();
 131                     conn.println("250-"+conn.vhost);
 132                     //conn.println("250-AUTH");
 133                     conn.println("250-AUTH PLAIN");
 134                     //conn.println("250-STARTTLS");
 135                     conn.println("250 HELP");
 136                     ehlo = true;
 137                     from = null; to = new Vector();
 138                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
 139                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
 140                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
 141                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
 142                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 143                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 144                 } else if (c.startsWith("STARTTLS")) {
 145                     conn.println("220 starting TLS...");
 146                     conn.flush();
 147                     conn = conn.negotiateSSL(true);
 148                     from = null; to = new Vector();
 149                 } else if (c.startsWith("AUTH")) {
 150                     if (authenticatedAs != null) {
 151                         conn.println("503 you are already authenticated; you must reconnect to reauth");
 152                     } else {
 153                         String mechanism = command.substring(4).trim();
 154                         String rest = "";
 155                         if (mechanism.indexOf(' ')!=-1) {
 156                             rest      = mechanism.substring(mechanism.indexOf(' ')+1).trim();
 157                             mechanism = mechanism.substring(0, mechanism.indexOf(' '));
 158                         }
 159                         if (mechanism.equals("PLAIN")) {
 160                             // 538 Encryption required for requested authentication mechanism?
 161                             byte[] bytes = Encode.fromBase64(rest);
 162                             String authenticateUser = null;
 163                             String authorizeUser = null;
 164                             String password = null;
 165                             int start = 0;
 166                             for(int i=0; i<=bytes.length; i++) {
 167                                 if (i<bytes.length && bytes[i]!=0) continue;
 168                                 String result = new String(bytes, start, i-start, "UTF-8");
 169                                 if (authenticateUser==null)   authenticateUser = result;
 170                                 else if (authorizeUser==null) authorizeUser = result;
 171                                 else if (password==null)      password = result;
 172                                 start = i+1;
 173                             }
 174                             // FIXME: be smarter here
 175                             if (Main.auth.login(authorizeUser, password)!=null)
 176                                 authenticatedAs = authenticateUser;
 177                             conn.println("235 Authentication successful");
 178                             /*
 179                         } else if (mechanism.equals("CRAM-MD5")) {
 180                             String challenge = ;
 181                             conn.println("334 "+challenge);
 182                             String resp = conn.readln();
 183                             if (resp.equals("*")) {
 184                                 conn.println("501 client requested AUTH cancellation");
 185                             }
 186                         } else if (mechanism.equals("ANONYMOUS")) {
 187                         } else if (mechanism.equals("EXTERNAL")) {
 188                         } else if (mechanism.equals("DIGEST-MD5")) {
 189                             */
 190                         } else {
 191                             conn.println("504 unrecognized authentication type");
 192                         }
 193                         // on success, reset to initial state; client will EHLO again
 194                         from = null; to = new Vector();
 195                     }
 196                 } else if (c.startsWith("MAIL FROM:")) {
 197                     command = command.substring(10).trim();
 198                     from = command.equals("<>") ? null : new Address(command);
 199                     conn.println("250 " + from + " is syntactically correct");
 200                     // Don't perform SAV; discouraged here
 201                     //   http://blog.fastmail.fm/2007/12/05/sending-email-servers-best-practice/
 202                 } else if (c.startsWith("RCPT TO:")) {
 203                     // some clients are broken and put RCPT first; we will tolerate this
 204                     command = command.substring(8).trim();
 205                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 206                     Address addr = new Address(command);
 207                     if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 208                         conn.println("250 you are connected locally, so I will let you send");
 209                         to.addElement(addr);
 210                         if (!whitelist.isWhitelisted(addr))
 211                             whitelist.addWhitelist(addr);
 212                     } else if (authenticatedAs!=null) {
 213                         conn.println("250 you are authenticated as "+authenticatedAs+", so I will let you send");
 214                         to.addElement(addr);
 215                         if (!whitelist.isWhitelisted(addr))
 216                             whitelist.addWhitelist(addr);
 217                     } else if (addr.isLocal()) {
 218                         if (to.size() > 3) {
 219                             conn.println("536 sorry, limit on 3 RCPT TO's per DATA");
 220                         } else {
 221                             // FEATURE: should check the address further and give 550 if undeliverable
 222                             conn.println("250 " + addr + " is on this machine; I will deliver it");
 223                             to.addElement(addr);
 224                         }
 225                     } else {
 226                         conn.println("535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 227                         Log.warn("","535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 228                         failedRcptCount++;
 229                         if (failedRcptCount > 3) {
 230                             conn.close();
 231                             return;
 232                         }
 233                     }
 234                     conn.flush();
 235                 } else if (c.startsWith("DATA")) {
 236                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 237                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 238                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress() && authenticatedAs==null) {
 239                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 240                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 241                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 242                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 243                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 244                             conn.flush();
 245                             continue;
 246                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 247                             graylist.addWhitelist(conn.getRemoteAddress());
 248                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 249                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 250                         } else {
 251                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 252                             conn.flush();
 253                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 254                             continue;
 255                         }
 256                     } else {
 257                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 258                     }
 259                     conn.flush();
 260                     try {
 261                         // FIXME: deal with messages larger than memory here?
 262                         StringBuffer buf = new StringBuffer();
 263                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 264                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 265                         buf.append("          for ");
 266                         // FIXME: this is leaking BCC addrs
 267                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 268                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 269
 270                         // FIXME: some sort of stream transformer here?
 271                         while(true) {
 272                             String s = conn.readln();
 273                             if (s == null) throw new RuntimeException("connection closed");
 274                             if (s.equals(".")) break;
 275                             if (s.startsWith(".")) s = s.substring(1);
 276                             buf.append(s + "\r\n");
 277                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE && (from+"").indexOf("paperless")==-1) {
 278                                 Log.error("**"+conn.getRemoteAddress()+"**",
 279                                           "sorry, this mail server only accepts messages of less than " +
 280                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 281                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 282                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 283                             }
 284                         }
 285                         String message = buf.toString();
 286                         Message m = null;
 287                         for(int i=0; i<to.size(); i++)
 288                             enqueue(m = Message.newMessage(Fountain.Util.create(message)).withEnvelope(from, (Address)to.elementAt(i)));
 289                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 290                         conn.println("250 message accepted");
 291                         conn.flush();
 292                         from = null; to = new Vector();
 293                     } catch (MailException.Malformed mfe) {    conn.println("501 " + mfe.toString());
 294                     } catch (MailException.MailboxFull mbf) {  conn.println("452 " + mbf);
 295                     } catch (Script.Later.LaterException le) { conn.println("453 try again later");
 296                     } catch (Script.Reject.RejectException re) {
 297                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 298                         conn.println("501 " + re.reason);
 299                     }
 300                 } else                    { conn.println("500 unrecognized command"); }
 301             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 302         }
 303     }
 304
 305
 306     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 307
 308     public static class Outgoing extends Thread {
 309
 310         private static final HashMap deadHosts = new HashMap();
 311         public static void enqueue(Message m) throws IOException {
 312             if (m == null) { Log.warn(Outgoing.class, "attempted to enqueue(null)"); return; }
 313             String traces = m.headers.get("Received");
 314             if (traces!=null) {
 315                 int lines = 0;
 316                 for(int i=0; i<traces.length(); i++)
 317                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 318                         lines++;
 319                 if (lines > 100) { // required by rfc
 320                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 321                     return;
 322                 }
 323             }
 324             synchronized(Outgoing.class) {
 325                 spool.insert(m, Mailbox.Flag.defaultFlags);
 326                 Outgoing.class.notifyAll();
 327             }
 328         }
 329
 330         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 331         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 332             if (m.envelopeTo == null) {
 333                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 334                 return false;
 335             }
 336             InetAddress[] mx = DNSUtil.getMailExchangerIPs(m.envelopeTo.host);
 337             if (mx.length == 0) {
 338                 if (!noBounces) {
 339                     enqueue(m.bounce("could not resolve " + m.envelopeTo.host));
 340                     return true;
 341                 } else {
 342                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 343                     return false;
 344                 }
 345             }
 346             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 347                 if (!noBounces) {
 348                     enqueue(m.bounce("could not send for 5 days"));
 349                     return true;
 350                 } else {
 351                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 352                     return false;
 353                 }
 354             }
 355             for(int i=0; i<mx.length; i++) {
 356                 //if (deadHosts.contains(mx[i])) continue;
 357                 if (attempt(m, mx[i])) return true;
 358             }
 359             return false;
 360         }
 361
 362         private static void check(String s, Connection conn) {
 363             if (s==null) return;
 364             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 365             //if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 366             if (!s.startsWith("2")&&!s.startsWith("3")) throw new SMTPException(s);
 367         }
 368         private static boolean attempt(final Message m, final InetAddress mx) {
 369             boolean accepted = false;
 370             Connection conn = null;
 371             try {
 372                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 373                 InetAddress localAddress = conn.getSocket().getLocalAddress();
 374                 String reverse = DNSUtil.reverseLookup(localAddress);
 375                 Log.info(SMTP.Outgoing.class,
 376                          "outbound connection to " + mx + " uses " + localAddress + " [reverse: " + reverse + "]");
 377                 InetAddress relookup = InetAddress.getByName(reverse);
 378                 if (!relookup.equals(localAddress))
 379                     Log.error(SMTP.Outgoing.class,
 380                               "Warning: local machine fails forward-confirmed-reverse; " +
 381                               reverse + " resolves to " + localAddress);
 382                 conn.setNewline("\r\n");
 383                 conn.setTimeout(60 * 1000);
 384                 check(conn.readln(), conn);  // banner
 385                 try {
 386                     conn.println("EHLO " + reverse);
 387                     check(conn.readln(), conn);
 388                 } catch (SMTPException smtpe) {
 389                     conn.println("HELO " + reverse);
 390                     check(conn.readln(), conn);
 391                 }
 392                 String envelopeFrom = m.envelopeFrom==null ? "" : m.envelopeFrom.toString();
 393                 conn.println("MAIL FROM:<" + envelopeFrom +">");            check(conn.readln(), conn);
 394                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");  check(conn.readln(), conn);
 395                 conn.println("DATA");                                       check(conn.readln(), conn);
 396
 397                 Headers head = new Headers(m.headers,
 398                                            new String[] {
 399                                                "return-path", null,
 400                                                "bcc", null
 401                                            });
 402                 Stream stream = head.getStream();
 403                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 404                     if (s.startsWith(".")) conn.print(".");
 405                     conn.println(s);
 406                 }
 407                 conn.println("");
 408                 stream = m.getBody().getStream();
 409                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 410                     if (s.startsWith(".")) conn.print(".");
 411                     conn.println(s);
 412                 }
 413                 conn.println(".");
 414                 String resp = conn.readln();
 415                 if (resp == null)
 416                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 417                 check(resp, conn);
 418                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 419                 accepted = true;
 420                 conn.close();
 421             } catch (SMTPException e) {
 422                 if (accepted) return true;
 423                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 424                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 425                 Log.warn(SMTP.Outgoing.class, e);
 426                 /*
 427                   // FIXME: we should not be bouncing here!
 428                 if (e.code >= 500 && e.code <= 599) {
 429                     try {
 430                         attempt(m.bounce("unable to deliver: " + e), true);
 431                     } catch (Exception ex) {
 432                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 433                         Log.error(SMTP.Outgoing.class, ex);
 434                     }
 435                     return true;
 436                 }
 437                 */
 438                 return false;
 439             } catch (Exception e) {
 440                 if (accepted) return true;
 441                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 442                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 443                 Log.warn(SMTP.Outgoing.class, e);
 444                 //if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 445                 return false;
 446             } finally {
 447                 if (conn != null) conn.close();
 448             }
 449             return accepted;
 450         }
 451
 452         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 453         private static int serials = 1;
 454         private int serial = serials++;
 455         private Mailbox.Iterator it;
 456
 457         private static Map<String,Long> nextTry = Collections.synchronizedMap(new HashMap<String,Long>());
 458
 459         public Outgoing() {
 460             synchronized(Outgoing.class) {
 461                 threads.add(this);
 462             }
 463         }
 464
 465         public void wake() {
 466             int count = spool.count(Query.all());
 467             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 468             try {
 469                 while(true) {
 470                     boolean good = false;
 471                     synchronized(Outgoing.class) {
 472                         it = spool.iterator();
 473                         OUTER: for(; it.next(); ) {
 474                             for(Outgoing o : threads)
 475                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 476                                     continue OUTER;
 477                             good = true;
 478                             break;
 479                         }
 480                     }
 481                     if (!good) break;
 482                     try {
 483                         String messageid = it.cur().messageid;
 484                         if (nextTry.get(messageid) == null || System.currentTimeMillis() > nextTry.get(messageid)) {
 485                             boolean ok = attempt(it.cur());
 486                             if (ok) it.delete();
 487                             else nextTry.put(messageid, System.currentTimeMillis() + RETRY_TIME);
 488                         }
 489                     } catch (Exception e) {
 490                         Log.error(SMTP.Outgoing.class, e);
 491                     }
 492                     Log.info(this, "sleeping for 3s...");
 493                     Thread.sleep(3000);
 494                 }
 495             } catch (Exception e) {
 496                 //if (e instanceof InterruptedException) throw e;
 497                 Log.error(SMTP.Outgoing.class, e);
 498             }
 499             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 500             it = null;
 501         }
 502
 503         public void run() {
 504             try {
 505                 while(true) {
 506                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 507                     wake();
 508                     Thread.sleep(1000);
 509                     synchronized(Outgoing.class) {
 510                         Outgoing.class.wait(5 * 60 * 1000);
 511                     }
 512                 }
 513             } catch (InterruptedException e) { Log.warn(this, e); }
 514         }
 515     }
 516
 517 }