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