citadel/modules/smtp/smtp_clienthandlers.c

   1 /*
   2  * This module is an SMTP and ESMTP implementation for the Citadel system.
   3  * It is compliant with all of the following:
   4  *
   5  * RFC  821 - Simple Mail Transfer Protocol
   6  * RFC  876 - Survey of SMTP Implementations
   7  * RFC 1047 - Duplicate messages and SMTP
   8  * RFC 1652 - 8 bit MIME
   9  * RFC 1869 - Extended Simple Mail Transfer Protocol
  10  * RFC 1870 - SMTP Service Extension for Message Size Declaration
  11  * RFC 2033 - Local Mail Transfer Protocol
  12  * RFC 2197 - SMTP Service Extension for Command Pipelining
  13  * RFC 2476 - Message Submission
  14  * RFC 2487 - SMTP Service Extension for Secure SMTP over TLS
  15  * RFC 2554 - SMTP Service Extension for Authentication
  16  * RFC 2821 - Simple Mail Transfer Protocol
  17  * RFC 2822 - Internet Message Format
  18  * RFC 2920 - SMTP Service Extension for Command Pipelining
  19  *
  20  * Copyright (c) 1998-2012 by the citadel.org team
  21  *
  22  *  This program is open source software; you can redistribute it and/or modify
  23  *  it under the terms of the GNU General Public License version 3.
  24  *
  25  *
  26  *
  27  *  This program is distributed in the hope that it will be useful,
  28  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  *  GNU General Public License for more details.
  31  *
  32  *
  33  *
  34  *
  35  */
  36
  37 #include "sysdep.h"
  38 #include <stdlib.h>
  39 #include <unistd.h>
  40 #include <stdio.h>
  41 #include <termios.h>
  42 #include <fcntl.h>
  43 #include <signal.h>
  44 #include <pwd.h>
  45 #include <errno.h>
  46 #include <sys/types.h>
  47 #include <syslog.h>
  48
  49 #if TIME_WITH_SYS_TIME
  50 # include <sys/time.h>
  51 # include <time.h>
  52 #else
  53 # if HAVE_SYS_TIME_H
  54 #  include <sys/time.h>
  55 # else
  56 #  include <time.h>
  57 # endif
  58 #endif
  59 #include <sys/wait.h>
  60 #include <ctype.h>
  61 #include <string.h>
  62 #include <limits.h>
  63 #include <sys/socket.h>
  64 #include <netinet/in.h>
  65 #include <arpa/inet.h>
  66 #include <libcitadel.h>
  67 #include "citadel.h"
  68 #include "server.h"
  69 #include "citserver.h"
  70 #include "support.h"
  71 #include "config.h"
  72 #include "control.h"
  73 #include "user_ops.h"
  74 #include "database.h"
  75 #include "msgbase.h"
  76 #include "internet_addressing.h"
  77 #include "genstamp.h"
  78 #include "domain.h"
  79 #include "clientsocket.h"
  80 #include "locate_host.h"
  81 #include "citadel_dirs.h"
  82
  83 #include "ctdl_module.h"
  84
  85 #include "smtp_util.h"
  86 #include "event_client.h"
  87 #include "smtpqueue.h"
  88 #include "smtp_clienthandlers.h"
  89
  90
  91 #define SMTP_ERROR(WHICH_ERR, ERRSTR) do {                             \
  92                 Msg->MyQEntry->Status = WHICH_ERR;                     \
  93                 StrBufAppendBufPlain(Msg->MyQEntry->StatusMessage,     \
  94                                      HKEY(ERRSTR), 0);                 \
  95                 return eAbort; }                                       \
  96         while (0)
  97
  98 #define SMTP_VERROR(WHICH_ERR) do {                            \
  99                 Msg->MyQEntry->Status = WHICH_ERR;             \
 100                 StrBufPlain(Msg->MyQEntry->StatusMessage,      \
 101                             ChrPtr(Msg->IO.IOBuf) + 4,         \
 102                             StrLength(Msg->IO.IOBuf) - 4);     \
 103                 return eAbort; }                               \
 104         while (0)
 105
 106 #define SMTP_IS_STATE(WHICH_STATE) (ChrPtr(Msg->IO.IOBuf)[0] == WHICH_STATE)
 107
 108 #define SMTP_DBG_SEND() \
 109         EVS_syslog(LOG_DEBUG, "> %s\n", ChrPtr(Msg->IO.SendBuf.Buf))
 110
 111 #define SMTP_DBG_READ() \
 112         EVS_syslog(LOG_DEBUG, "< %s\n", ChrPtr(Msg->IO.IOBuf))
 113
 114
 115 /*****************************************************************************/
 116 /*                     SMTP CLIENT STATE CALLBACKS                           */
 117 /*****************************************************************************/
 118 eNextState SMTPC_read_greeting(SmtpOutMsg *Msg)
 119 {
 120         /* Process the SMTP greeting from the server */
 121         AsyncIO *IO = &Msg->IO;
 122         SMTP_DBG_READ();
 123
 124         if (!SMTP_IS_STATE('2')) {
 125                 if (SMTP_IS_STATE('4'))
 126                         SMTP_VERROR(4);
 127                 else
 128                         SMTP_VERROR(5);
 129         }
 130         return eSendReply;
 131 }
 132
 133 eNextState SMTPC_send_EHLO(SmtpOutMsg *Msg)
 134 {
 135         AsyncIO *IO = &Msg->IO;
 136         /* At this point we know we are talking to a real SMTP server */
 137
 138         /* Do a EHLO command.  If it fails, try the HELO command. */
 139         StrBufPrintf(Msg->IO.SendBuf.Buf,
 140                      "EHLO %s\r\n", config.c_fqdn);
 141
 142         SMTP_DBG_SEND();
 143         return eReadMessage;
 144 }
 145
 146 eNextState SMTPC_read_EHLO_reply(SmtpOutMsg *Msg)
 147 {
 148         AsyncIO *IO = &Msg->IO;
 149         SMTP_DBG_READ();
 150
 151         if (SMTP_IS_STATE('2')) {
 152                 Msg->State ++;
 153
 154                 if ((Msg->pCurrRelay == NULL) ||
 155                     (Msg->pCurrRelay->User == NULL))
 156                         Msg->State ++; /* Skip auth... */
 157         }
 158         /* else we fall back to 'helo' */
 159         return eSendReply;
 160 }
 161
 162 eNextState STMPC_send_HELO(SmtpOutMsg *Msg)
 163 {
 164         AsyncIO *IO = &Msg->IO;
 165         StrBufPrintf(Msg->IO.SendBuf.Buf,
 166                      "HELO %s\r\n", config.c_fqdn);
 167
 168         SMTP_DBG_SEND();
 169         return eReadMessage;
 170 }
 171
 172 eNextState SMTPC_read_HELO_reply(SmtpOutMsg *Msg)
 173 {
 174         AsyncIO *IO = &Msg->IO;
 175         SMTP_DBG_READ();
 176
 177         if (!SMTP_IS_STATE('2'))
 178         {
 179                 if (SMTP_IS_STATE('4'))
 180                         SMTP_VERROR(4);
 181                 else
 182                         SMTP_VERROR(5);
 183         }
 184         if ((Msg->pCurrRelay == NULL) ||
 185             (Msg->pCurrRelay->User == NULL))
 186                 Msg->State ++; /* Skip auth... */
 187
 188         return eSendReply;
 189 }
 190
 191 eNextState SMTPC_send_auth(SmtpOutMsg *Msg)
 192 {
 193         AsyncIO *IO = &Msg->IO;
 194         char buf[SIZ];
 195         char encoded[1024];
 196
 197         if ((Msg->pCurrRelay == NULL) ||
 198             (Msg->pCurrRelay->User == NULL))
 199                 Msg->State ++; /* Skip auth, shouldn't even come here!... */
 200         else {
 201                 /* Do an AUTH command if necessary */
 202                 sprintf(buf, "%s%c%s%c%s",
 203                         Msg->pCurrRelay->User, '\0',
 204                         Msg->pCurrRelay->User, '\0',
 205                         Msg->pCurrRelay->Pass);
 206
 207                 CtdlEncodeBase64(encoded, buf,
 208                                  strlen(Msg->pCurrRelay->User) * 2 +
 209                                  strlen(Msg->pCurrRelay->Pass) + 2, 0);
 210
 211                 StrBufPrintf(Msg->IO.SendBuf.Buf,
 212                              "AUTH PLAIN %s\r\n", encoded);
 213         }
 214         SMTP_DBG_SEND();
 215         return eReadMessage;
 216 }
 217
 218 eNextState SMTPC_read_auth_reply(SmtpOutMsg *Msg)
 219 {
 220         AsyncIO *IO = &Msg->IO;
 221         /* Do an AUTH command if necessary */
 222
 223         SMTP_DBG_READ();
 224
 225         if (!SMTP_IS_STATE('2')) {
 226                 if (SMTP_IS_STATE('4'))
 227                         SMTP_VERROR(4);
 228                 else
 229                         SMTP_VERROR(5);
 230         }
 231         return eSendReply;
 232 }
 233
 234 eNextState SMTPC_send_FROM(SmtpOutMsg *Msg)
 235 {
 236         AsyncIO *IO = &Msg->IO;
 237         /* previous command succeeded, now try the MAIL FROM: command */
 238         StrBufPrintf(Msg->IO.SendBuf.Buf,
 239                      "MAIL FROM:<%s>\r\n",
 240                      Msg->envelope_from);
 241
 242         SMTP_DBG_SEND();
 243         return eReadMessage;
 244 }
 245
 246 eNextState SMTPC_read_FROM_reply(SmtpOutMsg *Msg)
 247 {
 248         AsyncIO *IO = &Msg->IO;
 249         SMTP_DBG_READ();
 250
 251         if (!SMTP_IS_STATE('2')) {
 252                 if (SMTP_IS_STATE('4'))
 253                         SMTP_VERROR(4);
 254                 else
 255                         SMTP_VERROR(5);
 256         }
 257         return eSendReply;
 258 }
 259
 260
 261 eNextState SMTPC_send_RCPT(SmtpOutMsg *Msg)
 262 {
 263         AsyncIO *IO = &Msg->IO;
 264         /* MAIL succeeded, now try the RCPT To: command */
 265         StrBufPrintf(Msg->IO.SendBuf.Buf,
 266                      "RCPT TO:<%s@%s>\r\n",
 267                      Msg->user,
 268                      Msg->node);
 269
 270         SMTP_DBG_SEND();
 271         return eReadMessage;
 272 }
 273
 274 eNextState SMTPC_read_RCPT_reply(SmtpOutMsg *Msg)
 275 {
 276         AsyncIO *IO = &Msg->IO;
 277         SMTP_DBG_READ();
 278
 279         if (!SMTP_IS_STATE('2')) {
 280                 if (SMTP_IS_STATE('4'))
 281                         SMTP_VERROR(4);
 282                 else
 283                         SMTP_VERROR(5);
 284         }
 285         return eSendReply;
 286 }
 287
 288 eNextState SMTPC_send_DATAcmd(SmtpOutMsg *Msg)
 289 {
 290         AsyncIO *IO = &Msg->IO;
 291         /* RCPT succeeded, now try the DATA command */
 292         StrBufPlain(Msg->IO.SendBuf.Buf,
 293                     HKEY("DATA\r\n"));
 294
 295         SMTP_DBG_SEND();
 296         return eReadMessage;
 297 }
 298
 299 eNextState SMTPC_read_DATAcmd_reply(SmtpOutMsg *Msg)
 300 {
 301         AsyncIO *IO = &Msg->IO;
 302         SMTP_DBG_READ();
 303
 304         if (!SMTP_IS_STATE('3')) {
 305                 if (SMTP_IS_STATE('4'))
 306                         SMTP_VERROR(3);
 307                 else
 308                         SMTP_VERROR(5);
 309         }
 310         return eSendReply;
 311 }
 312
 313 eNextState SMTPC_send_data_body(SmtpOutMsg *Msg)
 314 {
 315         StrBuf *Buf;
 316         /* If we reach this point, the server is expecting data.*/
 317
 318         Buf = Msg->IO.SendBuf.Buf;
 319         Msg->IO.SendBuf.Buf = Msg->msgtext;
 320         Msg->msgtext = Buf;
 321         Msg->State ++;
 322
 323         return eSendMore;
 324 }
 325
 326 eNextState SMTPC_send_terminate_data_body(SmtpOutMsg *Msg)
 327 {
 328         StrBuf *Buf;
 329
 330         Buf = Msg->IO.SendBuf.Buf;
 331         Msg->IO.SendBuf.Buf = Msg->msgtext;
 332         Msg->msgtext = Buf;
 333
 334         StrBufPlain(Msg->IO.SendBuf.Buf,
 335                     HKEY(".\r\n"));
 336
 337         return eReadMessage;
 338
 339 }
 340
 341 eNextState SMTPC_read_data_body_reply(SmtpOutMsg *Msg)
 342 {
 343         AsyncIO *IO = &Msg->IO;
 344         SMTP_DBG_READ();
 345
 346         if (!SMTP_IS_STATE('2')) {
 347                 if (SMTP_IS_STATE('4'))
 348                         SMTP_VERROR(4);
 349                 else
 350                         SMTP_VERROR(5);
 351         }
 352
 353         /* We did it! */
 354         StrBufPlain(Msg->MyQEntry->StatusMessage,
 355                     &ChrPtr(Msg->IO.RecvBuf.Buf)[4],
 356                     StrLength(Msg->IO.RecvBuf.Buf) - 4);
 357         Msg->MyQEntry->Status = 2;
 358         return eSendReply;
 359 }
 360
 361 eNextState SMTPC_send_QUIT(SmtpOutMsg *Msg)
 362 {
 363         AsyncIO *IO = &Msg->IO;
 364         StrBufPlain(Msg->IO.SendBuf.Buf,
 365                     HKEY("QUIT\r\n"));
 366
 367         SMTP_DBG_SEND();
 368         return eReadMessage;
 369 }
 370
 371 eNextState SMTPC_read_QUIT_reply(SmtpOutMsg *Msg)
 372 {
 373         AsyncIO *IO = &Msg->IO;
 374         SMTP_DBG_READ();
 375
 376         EVS_syslog(LOG_DEBUG,
 377                    "delivery to <%s> @ <%s> (%s) succeeded\n",
 378                    Msg->user,
 379                    Msg->node,
 380                    Msg->name);
 381
 382         return eTerminateConnection;
 383 }
 384
 385 eNextState SMTPC_read_dummy(SmtpOutMsg *Msg)
 386 {
 387         return eSendReply;
 388 }
 389
 390 eNextState SMTPC_send_dummy(SmtpOutMsg *Msg)
 391 {
 392         return eReadMessage;
 393 }
 394
 395 /*****************************************************************************/
 396 /*                     SMTP CLIENT DISPATCHER                                */
 397 /*****************************************************************************/
 398 SMTPReadHandler ReadHandlers[eMaxSMTPC] = {
 399         SMTPC_read_greeting,
 400         SMTPC_read_EHLO_reply,
 401         SMTPC_read_HELO_reply,
 402         SMTPC_read_auth_reply,
 403         SMTPC_read_FROM_reply,
 404         SMTPC_read_RCPT_reply,
 405         SMTPC_read_DATAcmd_reply,
 406         SMTPC_read_dummy,
 407         SMTPC_read_data_body_reply,
 408         SMTPC_read_QUIT_reply
 409 };
 410 SMTPSendHandler SendHandlers[eMaxSMTPC] = {
 411         SMTPC_send_dummy, /* we don't send a greeting, the server does... */
 412         SMTPC_send_EHLO,
 413         STMPC_send_HELO,
 414         SMTPC_send_auth,
 415         SMTPC_send_FROM,
 416         SMTPC_send_RCPT,
 417         SMTPC_send_DATAcmd,
 418         SMTPC_send_data_body,
 419         SMTPC_send_terminate_data_body,
 420         SMTPC_send_QUIT
 421 };
 422
 423 const double SMTP_C_ConnTimeout = 300.; /* wail 1 minute for connections... */
 424
 425 const double SMTP_C_ReadTimeouts[eMaxSMTPC] = {
 426         300., /* Greeting... */
 427         30., /* EHLO */
 428         30., /* HELO */
 429         30., /* Auth */
 430         30., /* From */
 431         90., /* RCPT */
 432         30., /* DATA */
 433         90., /* DATABody */
 434         90., /* end of body... */
 435         30.  /* QUIT */
 436 };
 437 const double SMTP_C_SendTimeouts[eMaxSMTPC] = {
 438         90., /* Greeting... */
 439         30., /* EHLO */
 440         30., /* HELO */
 441         30., /* Auth */
 442         30., /* From */
 443         30., /* RCPT */
 444         30., /* DATA */
 445         90., /* DATABody */
 446         900., /* end of body... */
 447         30.  /* QUIT */
 448 };
 449
 450 const ConstStr ReadErrors[eMaxSMTPC + 1] = {
 451         {HKEY("Connection broken during SMTP conversation")},
 452         {HKEY("Connection broken during SMTP EHLO")},
 453         {HKEY("Connection broken during SMTP HELO")},
 454         {HKEY("Connection broken during SMTP AUTH")},
 455         {HKEY("Connection broken during SMTP MAIL FROM")},
 456         {HKEY("Connection broken during SMTP RCPT")},
 457         {HKEY("Connection broken during SMTP DATA")},
 458         {HKEY("Connection broken during SMTP message transmit")},
 459         {HKEY("Connection broken during SMTP message transmit")},/* quit reply, don't care. */
 460         {HKEY("Connection broken during SMTP message transmit")},/* quit reply, don't care. */
 461         {HKEY("")}/* quit reply, don't care. */
 462 };
 463
 464
 465
 466
 467
 468 int smtp_resolve_recipients(SmtpOutMsg *Msg)
 469 {
 470         AsyncIO *IO = &Msg->IO;
 471         const char *ptr;
 472         char buf[1024];
 473         int scan_done;
 474         int lp, rp;
 475         int i;
 476
 477         EVNCS_syslog(LOG_DEBUG, "%s\n", __FUNCTION__);
 478
 479         if ((Msg==NULL) ||
 480             (Msg->MyQEntry == NULL) ||
 481             (StrLength(Msg->MyQEntry->Recipient) == 0)) {
 482                 return 0;
 483         }
 484
 485         /* Parse out the host portion of the recipient address */
 486         process_rfc822_addr(ChrPtr(Msg->MyQEntry->Recipient),
 487                             Msg->user,
 488                             Msg->node,
 489                             Msg->name);
 490
 491         EVNCS_syslog(LOG_DEBUG,
 492                      "Attempting delivery to <%s> @ <%s> (%s)\n",
 493                      Msg->user,
 494                      Msg->node,
 495                      Msg->name);
 496
 497         /* If no envelope_from is supplied, extract one from the message */
 498         Msg->envelope_from = ChrPtr(Msg->MyQItem->EnvelopeFrom);
 499         if ( (Msg->envelope_from == NULL) ||
 500              (IsEmptyStr(Msg->envelope_from)) ) {
 501                 Msg->mailfrom[0] = '\0';
 502                 scan_done = 0;
 503                 ptr = ChrPtr(Msg->msgtext);
 504                 do {
 505                         if (ptr = cmemreadline(ptr, buf, sizeof buf), *ptr == 0)
 506                         {
 507                                 scan_done = 1;
 508                         }
 509                         if (!strncasecmp(buf, "From:", 5))
 510                         {
 511                                 safestrncpy(Msg->mailfrom,
 512                                             &buf[5],
 513                                             sizeof Msg->mailfrom);
 514
 515                                 striplt(Msg->mailfrom);
 516                                 for (i=0; Msg->mailfrom[i]; ++i) {
 517                                         if (!isprint(Msg->mailfrom[i]))
 518                                         {
 519                                                 strcpy(&Msg->mailfrom[i],
 520                                                        &Msg->mailfrom[i+1]);
 521                                                 i=0;
 522                                         }
 523                                 }
 524
 525                                 /* Strip out parenthesized names */
 526                                 lp = (-1);
 527                                 rp = (-1);
 528                                 for (i=0;
 529                                      !IsEmptyStr(Msg->mailfrom + i);
 530                                      ++i)
 531                                 {
 532                                         if (Msg->mailfrom[i] == '(') lp = i;
 533                                         if (Msg->mailfrom[i] == ')') rp = i;
 534                                 }
 535                                 if ((lp>0)&&(rp>lp))
 536                                 {
 537                                         strcpy(&Msg->mailfrom[lp-1],
 538                                                &Msg->mailfrom[rp+1]);
 539                                 }
 540
 541                                 /* Prefer brokketized names */
 542                                 lp = (-1);
 543                                 rp = (-1);
 544                                 for (i=0;
 545                                      !IsEmptyStr(Msg->mailfrom + i);
 546                                      ++i)
 547                                 {
 548                                         if (Msg->mailfrom[i] == '<') lp = i;
 549                                         if (Msg->mailfrom[i] == '>') rp = i;
 550                                 }
 551                                 if ( (lp>=0) && (rp>lp) ) {
 552                                         Msg->mailfrom[rp] = 0;
 553                                         memmove(Msg->mailfrom,
 554                                                 &Msg->mailfrom[lp + 1],
 555                                                 rp - lp);
 556                                 }
 557
 558                                 scan_done = 1;
 559                         }
 560                 } while (scan_done == 0);
 561                 if (IsEmptyStr(Msg->mailfrom))
 562                         strcpy(Msg->mailfrom, "someone@somewhere.org");
 563
 564                 stripallbut(Msg->mailfrom, '<', '>');
 565                 Msg->envelope_from = Msg->mailfrom;
 566         }
 567
 568         return 1;
 569 }