citadel/modules/smtp/serv_smtp.c

   1 /*
   2  * $Id$
   3  *
   4  * This module is an SMTP and ESMTP implementation for the Citadel system.
   5  * It is compliant with all of the following:
   6  *
   7  * RFC  821 - Simple Mail Transfer Protocol
   8  * RFC  876 - Survey of SMTP Implementations
   9  * RFC 1047 - Duplicate messages and SMTP
  10  * RFC 1652 - 8 bit MIME
  11  * RFC 1869 - Extended Simple Mail Transfer Protocol
  12  * RFC 1870 - SMTP Service Extension for Message Size Declaration
  13  * RFC 2033 - Local Mail Transfer Protocol
  14  * RFC 2197 - SMTP Service Extension for Command Pipelining
  15  * RFC 2476 - Message Submission
  16  * RFC 2487 - SMTP Service Extension for Secure SMTP over TLS
  17  * RFC 2554 - SMTP Service Extension for Authentication
  18  * RFC 2821 - Simple Mail Transfer Protocol
  19  * RFC 2822 - Internet Message Format
  20  * RFC 2920 - SMTP Service Extension for Command Pipelining
  21  *
  22  * The VRFY and EXPN commands have been removed from this implementation
  23  * because nobody uses these commands anymore, except for spammers.
  24  *
  25  */
  26
  27 #include "sysdep.h"
  28 #include <stdlib.h>
  29 #include <unistd.h>
  30 #include <stdio.h>
  31 #include <fcntl.h>
  32 #include <signal.h>
  33 #include <pwd.h>
  34 #include <errno.h>
  35 #include <sys/types.h>
  36 #include <syslog.h>
  37
  38 #if TIME_WITH_SYS_TIME
  39 # include <sys/time.h>
  40 # include <time.h>
  41 #else
  42 # if HAVE_SYS_TIME_H
  43 #  include <sys/time.h>
  44 # else
  45 #  include <time.h>
  46 # endif
  47 #endif
  48
  49 #include <sys/wait.h>
  50 #include <ctype.h>
  51 #include <string.h>
  52 #include <limits.h>
  53 #include <sys/socket.h>
  54 #include <netinet/in.h>
  55 #include <arpa/inet.h>
  56 #include <libcitadel.h>
  57 #include "citadel.h"
  58 #include "server.h"
  59 #include "citserver.h"
  60 #include "support.h"
  61 #include "config.h"
  62 #include "control.h"
  63 #include "room_ops.h"
  64 #include "user_ops.h"
  65 #include "policy.h"
  66 #include "database.h"
  67 #include "msgbase.h"
  68 #include "internet_addressing.h"
  69 #include "genstamp.h"
  70 #include "domain.h"
  71 #include "clientsocket.h"
  72 #include "locate_host.h"
  73 #include "citadel_dirs.h"
  74
  75
  76
  77 #ifndef HAVE_SNPRINTF
  78 #include "snprintf.h"
  79 #endif
  80
  81
  82 #include "ctdl_module.h"
  83
  84
  85
  86 struct citsmtp {                /* Information about the current session */
  87         int command_state;
  88         char helo_node[SIZ];
  89         char from[SIZ];
  90         char recipients[SIZ];
  91         int number_of_recipients;
  92         int delivery_mode;
  93         int message_originated_locally;
  94         int is_lmtp;
  95         int is_unfiltered;
  96         int is_msa;
  97 };
  98
  99 enum {                          /* Command states for login authentication */
 100         smtp_command,
 101         smtp_user,
 102         smtp_password,
 103         smtp_plain
 104 };
 105
 106 #define SMTP            ((struct citsmtp *)CC->session_specific_data)
 107
 108
 109 int run_queue_now = 0;  /* Set to 1 to ignore SMTP send retry times */
 110
 111
 112
 113 /*****************************************************************************/
 114 /*                      SMTP SERVER (INBOUND) STUFF                          */
 115 /*****************************************************************************/
 116
 117
 118 /*
 119  * Here's where our SMTP session begins its happy day.
 120  */
 121 void smtp_greeting(int is_msa)
 122 {
 123         char message_to_spammer[1024];
 124
 125         strcpy(CC->cs_clientname, "SMTP session");
 126         CC->internal_pgm = 1;
 127         CC->cs_flags |= CS_STEALTH;
 128         CC->session_specific_data = malloc(sizeof(struct citsmtp));
 129         memset(SMTP, 0, sizeof(struct citsmtp));
 130         SMTP->is_msa = is_msa;
 131
 132         /* If this config option is set, reject connections from problem
 133          * addresses immediately instead of after they execute a RCPT
 134          */
 135         if ( (config.c_rbl_at_greeting) && (SMTP->is_msa == 0) ) {
 136                 if (rbl_check(message_to_spammer)) {
 137                         if (CtdlThreadCheckStop())
 138                                 cprintf("421 %s\r\n", message_to_spammer);
 139                         else
 140                                 cprintf("550 %s\r\n", message_to_spammer);
 141                         CC->kill_me = 1;
 142                         /* no need to free_recipients(valid), it's not allocated yet */
 143                         return;
 144                 }
 145         }
 146
 147         /* Otherwise we're either clean or we check later. */
 148
 149         if (CC->nologin==1) {
 150                 cprintf("500 Too many users are already online (maximum is %d)\r\n",
 151                         config.c_maxsessions
 152                 );
 153                 CC->kill_me = 1;
 154                 /* no need to free_recipients(valid), it's not allocated yet */
 155                 return;
 156         }
 157
 158         /* Note: the FQDN *must* appear as the first thing after the 220 code.
 159          * Some clients (including citmail.c) depend on it being there.
 160          */
 161         cprintf("220 %s ESMTP Citadel server ready.\r\n", config.c_fqdn);
 162 }
 163
 164
 165 /*
 166  * SMTPS is just like SMTP, except it goes crypto right away.
 167  */
 168 void smtps_greeting(void) {
 169         CtdlModuleStartCryptoMsgs(NULL, NULL, NULL);
 170 #ifdef HAVE_OPENSSL
 171         if (!CC->redirect_ssl) CC->kill_me = 1;         /* kill session if no crypto */
 172 #endif
 173         smtp_greeting(0);
 174 }
 175
 176
 177 /*
 178  * SMTP MSA port requires authentication.
 179  */
 180 void smtp_msa_greeting(void) {
 181         smtp_greeting(1);
 182 }
 183
 184
 185 /*
 186  * LMTP is like SMTP but with some extra bonus footage added.
 187  */
 188 void lmtp_greeting(void) {
 189         smtp_greeting(0);
 190         SMTP->is_lmtp = 1;
 191 }
 192
 193
 194 /*
 195  * Generic SMTP MTA greeting
 196  */
 197 void smtp_mta_greeting(void) {
 198         smtp_greeting(0);
 199 }
 200
 201
 202 /*
 203  * We also have an unfiltered LMTP socket that bypasses spam filters.
 204  */
 205 void lmtp_unfiltered_greeting(void) {
 206         smtp_greeting(0);
 207         SMTP->is_lmtp = 1;
 208         SMTP->is_unfiltered = 1;
 209 }
 210
 211
 212 /*
 213  * Login greeting common to all auth methods
 214  */
 215 void smtp_auth_greeting(void) {
 216                 cprintf("235 Hello, %s\r\n", CC->user.fullname);
 217                 CtdlLogPrintf(CTDL_NOTICE, "SMTP authenticated %s\n", CC->user.fullname);
 218                 CC->internal_pgm = 0;
 219                 CC->cs_flags &= ~CS_STEALTH;
 220 }
 221
 222
 223 /*
 224  * Implement HELO and EHLO commands.
 225  *
 226  * which_command:  0=HELO, 1=EHLO, 2=LHLO
 227  */
 228 void smtp_hello(char *argbuf, int which_command) {
 229
 230         safestrncpy(SMTP->helo_node, argbuf, sizeof SMTP->helo_node);
 231
 232         if ( (which_command != 2) && (SMTP->is_lmtp) ) {
 233                 cprintf("500 Only LHLO is allowed when running LMTP\r\n");
 234                 return;
 235         }
 236
 237         if ( (which_command == 2) && (SMTP->is_lmtp == 0) ) {
 238                 cprintf("500 LHLO is only allowed when running LMTP\r\n");
 239                 return;
 240         }
 241
 242         if (which_command == 0) {
 243                 cprintf("250 Hello %s (%s [%s])\r\n",
 244                         SMTP->helo_node,
 245                         CC->cs_host,
 246                         CC->cs_addr
 247                 );
 248         }
 249         else {
 250                 if (which_command == 1) {
 251                         cprintf("250-Hello %s (%s [%s])\r\n",
 252                                 SMTP->helo_node,
 253                                 CC->cs_host,
 254                                 CC->cs_addr
 255                         );
 256                 }
 257                 else {
 258                         cprintf("250-Greetings and joyous salutations.\r\n");
 259                 }
 260                 cprintf("250-HELP\r\n");
 261                 cprintf("250-SIZE %ld\r\n", config.c_maxmsglen);
 262
 263 #ifdef HAVE_OPENSSL
 264                 /*
 265                  * Offer TLS, but only if TLS is not already active.
 266                  * Furthermore, only offer TLS when running on
 267                  * the SMTP-MSA port, not on the SMTP-MTA port, due to
 268                  * questionable reliability of TLS in certain sending MTA's.
 269                  */
 270                 if ( (!CC->redirect_ssl) && (SMTP->is_msa) ) {
 271                         cprintf("250-STARTTLS\r\n");
 272                 }
 273 #endif  /* HAVE_OPENSSL */
 274
 275                 cprintf("250-AUTH LOGIN PLAIN\r\n"
 276                         "250-AUTH=LOGIN PLAIN\r\n"
 277                         "250 8BITMIME\r\n"
 278                 );
 279         }
 280 }
 281
 282
 283
 284 /*
 285  * Implement HELP command.
 286  */
 287 void smtp_help(void) {
 288         cprintf("214 RTFM http://www.ietf.org/rfc/rfc2821.txt\r\n");
 289 }
 290
 291
 292 /*
 293  *
 294  */
 295 void smtp_get_user(char *argbuf) {
 296         char buf[SIZ];
 297         char username[SIZ];
 298
 299         CtdlDecodeBase64(username, argbuf, SIZ);
 300         /* CtdlLogPrintf(CTDL_DEBUG, "Trying <%s>\n", username); */
 301         if (CtdlLoginExistingUser(NULL, username) == login_ok) {
 302                 CtdlEncodeBase64(buf, "Password:", 9, 0);
 303                 cprintf("334 %s\r\n", buf);
 304                 SMTP->command_state = smtp_password;
 305         }
 306         else {
 307                 cprintf("500 No such user.\r\n");
 308                 SMTP->command_state = smtp_command;
 309         }
 310 }
 311
 312
 313 /*
 314  *
 315  */
 316 void smtp_get_pass(char *argbuf) {
 317         char password[SIZ];
 318
 319         CtdlDecodeBase64(password, argbuf, SIZ);
 320         /* CtdlLogPrintf(CTDL_DEBUG, "Trying <%s>\n", password); */
 321         if (CtdlTryPassword(password) == pass_ok) {
 322                 smtp_auth_greeting();
 323         }
 324         else {
 325                 cprintf("535 Authentication failed.\r\n");
 326         }
 327         SMTP->command_state = smtp_command;
 328 }
 329
 330
 331 /*
 332  * Back end for PLAIN auth method (either inline or multistate)
 333  */
 334 void smtp_try_plain(char *encoded_authstring) {
 335         char decoded_authstring[1024];
 336         char ident[256];
 337         char user[256];
 338         char pass[256];
 339         int result;
 340
 341         CtdlDecodeBase64(decoded_authstring, encoded_authstring, strlen(encoded_authstring) );
 342         safestrncpy(ident, decoded_authstring, sizeof ident);
 343         safestrncpy(user, &decoded_authstring[strlen(ident) + 1], sizeof user);
 344         safestrncpy(pass, &decoded_authstring[strlen(ident) + strlen(user) + 2], sizeof pass);
 345
 346         SMTP->command_state = smtp_command;
 347
 348         if (!IsEmptyStr(ident)) {
 349                 result = CtdlLoginExistingUser(user, ident);
 350         }
 351         else {
 352                 result = CtdlLoginExistingUser(NULL, user);
 353         }
 354
 355         if (result == login_ok) {
 356                 if (CtdlTryPassword(pass) == pass_ok) {
 357                         smtp_auth_greeting();
 358                         return;
 359                 }
 360         }
 361         cprintf("504 Authentication failed.\r\n");
 362 }
 363
 364
 365 /*
 366  * Attempt to perform authenticated SMTP
 367  */
 368 void smtp_auth(char *argbuf) {
 369         char username_prompt[64];
 370         char method[64];
 371         char encoded_authstring[1024];
 372
 373         if (CC->logged_in) {
 374                 cprintf("504 Already logged in.\r\n");
 375                 return;
 376         }
 377
 378         extract_token(method, argbuf, 0, ' ', sizeof method);
 379
 380         if (!strncasecmp(method, "login", 5) ) {
 381                 if (strlen(argbuf) >= 7) {
 382                         smtp_get_user(&argbuf[6]);
 383                 }
 384                 else {
 385                         CtdlEncodeBase64(username_prompt, "Username:", 9, 0);
 386                         cprintf("334 %s\r\n", username_prompt);
 387                         SMTP->command_state = smtp_user;
 388                 }
 389                 return;
 390         }
 391
 392         if (!strncasecmp(method, "plain", 5) ) {
 393                 if (num_tokens(argbuf, ' ') < 2) {
 394                         cprintf("334 \r\n");
 395                         SMTP->command_state = smtp_plain;
 396                         return;
 397                 }
 398
 399                 extract_token(encoded_authstring, argbuf, 1, ' ', sizeof encoded_authstring);
 400
 401                 smtp_try_plain(encoded_authstring);
 402                 return;
 403         }
 404
 405         if (strncasecmp(method, "login", 5) ) {
 406                 cprintf("504 Unknown authentication method.\r\n");
 407                 return;
 408         }
 409
 410 }
 411
 412
 413 /*
 414  * Implements the RSET (reset state) command.
 415  * Currently this just zeroes out the state buffer.  If pointers to data
 416  * allocated with malloc() are ever placed in the state buffer, we have to
 417  * be sure to free() them first!
 418  *
 419  * Set do_response to nonzero to output the SMTP RSET response code.
 420  */
 421 void smtp_rset(int do_response) {
 422         int is_lmtp;
 423         int is_unfiltered;
 424
 425         /*
 426          * Our entire SMTP state is discarded when a RSET command is issued,
 427          * but we need to preserve this one little piece of information, so
 428          * we save it for later.
 429          */
 430         is_lmtp = SMTP->is_lmtp;
 431         is_unfiltered = SMTP->is_unfiltered;
 432
 433         memset(SMTP, 0, sizeof(struct citsmtp));
 434
 435         /*
 436          * It is somewhat ambiguous whether we want to log out when a RSET
 437          * command is issued.  Here's the code to do it.  It is commented out
 438          * because some clients (such as Pine) issue RSET commands before
 439          * each message, but still expect to be logged in.
 440          *
 441          * if (CC->logged_in) {
 442          *      logout(CC);
 443          * }
 444          */
 445
 446         /*
 447          * Reinstate this little piece of information we saved (see above).
 448          */
 449         SMTP->is_lmtp = is_lmtp;
 450         SMTP->is_unfiltered = is_unfiltered;
 451
 452         if (do_response) {
 453                 cprintf("250 Zap!\r\n");
 454         }
 455 }
 456
 457 /*
 458  * Clear out the portions of the state buffer that need to be cleared out
 459  * after the DATA command finishes.
 460  */
 461 void smtp_data_clear(void) {
 462         strcpy(SMTP->from, "");
 463         strcpy(SMTP->recipients, "");
 464         SMTP->number_of_recipients = 0;
 465         SMTP->delivery_mode = 0;
 466         SMTP->message_originated_locally = 0;
 467 }
 468
 469 const char *smtp_get_Recipients(void)
 470 {
 471         if (SMTP == NULL)
 472                 return NULL;
 473         else return SMTP->from;
 474
 475 }
 476
 477 /*
 478  * Implements the "MAIL From:" command
 479  */
 480 void smtp_mail(char *argbuf) {
 481         char user[SIZ];
 482         char node[SIZ];
 483         char name[SIZ];
 484
 485         if (!IsEmptyStr(SMTP->from)) {
 486                 cprintf("503 Only one sender permitted\r\n");
 487                 return;
 488         }
 489
 490         if (strncasecmp(argbuf, "From:", 5)) {
 491                 cprintf("501 Syntax error\r\n");
 492                 return;
 493         }
 494
 495         strcpy(SMTP->from, &argbuf[5]);
 496         striplt(SMTP->from);
 497         if (haschar(SMTP->from, '<') > 0) {
 498                 stripallbut(SMTP->from, '<', '>');
 499         }
 500
 501         /* We used to reject empty sender names, until it was brought to our
 502          * attention that RFC1123 5.2.9 requires that this be allowed.  So now
 503          * we allow it, but replace the empty string with a fake
 504          * address so we don't have to contend with the empty string causing
 505          * other code to fail when it's expecting something there.
 506          */
 507         if (IsEmptyStr(SMTP->from)) {
 508                 strcpy(SMTP->from, "someone@example.com");
 509         }
 510
 511         /* If this SMTP connection is from a logged-in user, force the 'from'
 512          * to be the user's Internet e-mail address as Citadel knows it.
 513          */
 514         if (CC->logged_in) {
 515                 safestrncpy(SMTP->from, CC->cs_inet_email, sizeof SMTP->from);
 516                 cprintf("250 Sender ok <%s>\r\n", SMTP->from);
 517                 SMTP->message_originated_locally = 1;
 518                 return;
 519         }
 520
 521         else if (SMTP->is_lmtp) {
 522                 /* Bypass forgery checking for LMTP */
 523         }
 524
 525         /* Otherwise, make sure outsiders aren't trying to forge mail from
 526          * this system (unless, of course, c_allow_spoofing is enabled)
 527          */
 528         else if (config.c_allow_spoofing == 0) {
 529                 process_rfc822_addr(SMTP->from, user, node, name);
 530                 if (CtdlHostAlias(node) != hostalias_nomatch) {
 531                         cprintf("550 You must log in to send mail from %s\r\n", node);
 532                         strcpy(SMTP->from, "");
 533                         return;
 534                 }
 535         }
 536
 537         cprintf("250 Sender ok\r\n");
 538 }
 539
 540
 541
 542 /*
 543  * Implements the "RCPT To:" command
 544  */
 545 void smtp_rcpt(char *argbuf) {
 546         char recp[1024];
 547         char message_to_spammer[SIZ];
 548         struct recptypes *valid = NULL;
 549
 550         if (IsEmptyStr(SMTP->from)) {
 551                 cprintf("503 Need MAIL before RCPT\r\n");
 552                 return;
 553         }
 554
 555         if (strncasecmp(argbuf, "To:", 3)) {
 556                 cprintf("501 Syntax error\r\n");
 557                 return;
 558         }
 559
 560         if ( (SMTP->is_msa) && (!CC->logged_in) ) {
 561                 cprintf("550 You must log in to send mail on this port.\r\n");
 562                 strcpy(SMTP->from, "");
 563                 return;
 564         }
 565
 566         safestrncpy(recp, &argbuf[3], sizeof recp);
 567         striplt(recp);
 568         stripallbut(recp, '<', '>');
 569
 570         if ( (strlen(recp) + strlen(SMTP->recipients) + 1 ) >= SIZ) {
 571                 cprintf("452 Too many recipients\r\n");
 572                 return;
 573         }
 574
 575         /* RBL check */
 576         if ( (!CC->logged_in)   /* Don't RBL authenticated users */
 577            && (!SMTP->is_lmtp) ) {      /* Don't RBL LMTP clients */
 578                 if (config.c_rbl_at_greeting == 0) {    /* Don't RBL again if we already did it */
 579                         if (rbl_check(message_to_spammer)) {
 580                                 if (CtdlThreadCheckStop())
 581                                         cprintf("421 %s\r\n", message_to_spammer);
 582                                 else
 583                                         cprintf("550 %s\r\n", message_to_spammer);
 584                                 /* no need to free_recipients(valid), it's not allocated yet */
 585                                 return;
 586                         }
 587                 }
 588         }
 589
 590         valid = validate_recipients(recp,
 591                                     smtp_get_Recipients (),
 592                                     (SMTP->is_lmtp)? POST_LMTP:
 593                                        (CC->logged_in)? POST_LOGGED_IN:
 594                                                         POST_EXTERNAL);
 595         if (valid->num_error != 0) {
 596                 cprintf("550 %s\r\n", valid->errormsg);
 597                 free_recipients(valid);
 598                 return;
 599         }
 600
 601         if (valid->num_internet > 0) {
 602                 if (CC->logged_in) {
 603                         if (CtdlCheckInternetMailPermission(&CC->user)==0) {
 604                                 cprintf("551 <%s> - you do not have permission to send Internet mail\r\n", recp);
 605                                 free_recipients(valid);
 606                                 return;
 607                         }
 608                 }
 609         }
 610
 611         if (valid->num_internet > 0) {
 612                 if ( (SMTP->message_originated_locally == 0)
 613                    && (SMTP->is_lmtp == 0) ) {
 614                         cprintf("551 <%s> - relaying denied\r\n", recp);
 615                         free_recipients(valid);
 616                         return;
 617                 }
 618         }
 619
 620         cprintf("250 RCPT ok <%s>\r\n", recp);
 621         if (!IsEmptyStr(SMTP->recipients)) {
 622                 strcat(SMTP->recipients, ",");
 623         }
 624         strcat(SMTP->recipients, recp);
 625         SMTP->number_of_recipients += 1;
 626         if (valid != NULL)  {
 627                 free_recipients(valid);
 628         }
 629 }
 630
 631
 632
 633
 634 /*
 635  * Implements the DATA command
 636  */
 637 void smtp_data(void) {
 638         char *body;
 639         struct CtdlMessage *msg = NULL;
 640         long msgnum = (-1L);
 641         char nowstamp[SIZ];
 642         struct recptypes *valid;
 643         int scan_errors;
 644         int i;
 645         char result[SIZ];
 646
 647         if (IsEmptyStr(SMTP->from)) {
 648                 cprintf("503 Need MAIL command first.\r\n");
 649                 return;
 650         }
 651
 652         if (SMTP->number_of_recipients < 1) {
 653                 cprintf("503 Need RCPT command first.\r\n");
 654                 return;
 655         }
 656
 657         cprintf("354 Transmit message now - terminate with '.' by itself\r\n");
 658
 659         datestring(nowstamp, sizeof nowstamp, time(NULL), DATESTRING_RFC822);
 660         body = malloc(4096);
 661
 662         if (body != NULL) snprintf(body, 4096,
 663                 "Received: from %s (%s [%s])\n"
 664                 "       by %s; %s\n",
 665                         SMTP->helo_node,
 666                         CC->cs_host,
 667                         CC->cs_addr,
 668                         config.c_fqdn,
 669                         nowstamp);
 670
 671         body = CtdlReadMessageBody(".", config.c_maxmsglen, body, 1, 0);
 672         if (body == NULL) {
 673                 cprintf("550 Unable to save message: internal error.\r\n");
 674                 return;
 675         }
 676
 677         CtdlLogPrintf(CTDL_DEBUG, "Converting message...\n");
 678         msg = convert_internet_message(body);
 679
 680         /* If the user is locally authenticated, FORCE the From: header to
 681          * show up as the real sender.  Yes, this violates the RFC standard,
 682          * but IT MAKES SENSE.  If you prefer strict RFC adherence over
 683          * common sense, you can disable this in the configuration.
 684          *
 685          * We also set the "message room name" ('O' field) to MAILROOM
 686          * (which is Mail> on most systems) to prevent it from getting set
 687          * to something ugly like "0000058008.Sent Items>" when the message
 688          * is read with a Citadel client.
 689          */
 690         if ( (CC->logged_in) && (config.c_rfc822_strict_from == 0) ) {
 691                 if (msg->cm_fields['A'] != NULL) free(msg->cm_fields['A']);
 692                 if (msg->cm_fields['N'] != NULL) free(msg->cm_fields['N']);
 693                 if (msg->cm_fields['H'] != NULL) free(msg->cm_fields['H']);
 694                 if (msg->cm_fields['F'] != NULL) free(msg->cm_fields['F']);
 695                 if (msg->cm_fields['O'] != NULL) free(msg->cm_fields['O']);
 696                 msg->cm_fields['A'] = strdup(CC->user.fullname);
 697                 msg->cm_fields['N'] = strdup(config.c_nodename);
 698                 msg->cm_fields['H'] = strdup(config.c_humannode);
 699                 msg->cm_fields['F'] = strdup(CC->cs_inet_email);
 700                 msg->cm_fields['O'] = strdup(MAILROOM);
 701         }
 702
 703         /* Set the "envelope from" address */
 704         if (msg->cm_fields['P'] != NULL) {
 705                 free(msg->cm_fields['P']);
 706         }
 707         msg->cm_fields['P'] = strdup(SMTP->from);
 708
 709         /* Set the "envelope to" address */
 710         if (msg->cm_fields['V'] != NULL) {
 711                 free(msg->cm_fields['V']);
 712         }
 713         msg->cm_fields['V'] = strdup(SMTP->recipients);
 714
 715         /* Submit the message into the Citadel system. */
 716         valid = validate_recipients(SMTP->recipients,
 717                                     smtp_get_Recipients (),
 718                                     (SMTP->is_lmtp)? POST_LMTP:
 719                                        (CC->logged_in)? POST_LOGGED_IN:
 720                                                         POST_EXTERNAL);
 721
 722         /* If there are modules that want to scan this message before final
 723          * submission (such as virus checkers or spam filters), call them now
 724          * and give them an opportunity to reject the message.
 725          */
 726         if (SMTP->is_unfiltered) {
 727                 scan_errors = 0;
 728         }
 729         else {
 730                 scan_errors = PerformMessageHooks(msg, EVT_SMTPSCAN);
 731         }
 732
 733         if (scan_errors > 0) {  /* We don't want this message! */
 734
 735                 if (msg->cm_fields['0'] == NULL) {
 736                         msg->cm_fields['0'] = strdup("Message rejected by filter");
 737                 }
 738
 739                 sprintf(result, "550 %s\r\n", msg->cm_fields['0']);
 740         }
 741
 742         else {                  /* Ok, we'll accept this message. */
 743                 msgnum = CtdlSubmitMsg(msg, valid, "");
 744                 if (msgnum > 0L) {
 745                         sprintf(result, "250 Message accepted.\r\n");
 746                 }
 747                 else {
 748                         sprintf(result, "550 Internal delivery error\r\n");
 749                 }
 750         }
 751
 752         /* For SMTP and ESTMP, just print the result message.  For LMTP, we
 753          * have to print one result message for each recipient.  Since there
 754          * is nothing in Citadel which would cause different recipients to
 755          * have different results, we can get away with just spitting out the
 756          * same message once for each recipient.
 757          */
 758         if (SMTP->is_lmtp) {
 759                 for (i=0; i<SMTP->number_of_recipients; ++i) {
 760                         cprintf("%s", result);
 761                 }
 762         }
 763         else {
 764                 cprintf("%s", result);
 765         }
 766
 767         /* Write something to the syslog (which may or may not be where the
 768          * rest of the Citadel logs are going; some sysadmins want LOG_MAIL).
 769          */
 770         if (enable_syslog) {
 771                 syslog((LOG_MAIL | LOG_INFO),
 772                         "%ld: from=<%s>, nrcpts=%d, relay=%s [%s], stat=%s",
 773                         msgnum,
 774                         SMTP->from,
 775                         SMTP->number_of_recipients,
 776                         CC->cs_host,
 777                         CC->cs_addr,
 778                         result
 779                 );
 780         }
 781
 782         /* Clean up */
 783         CtdlFreeMessage(msg);
 784         free_recipients(valid);
 785         smtp_data_clear();      /* clear out the buffers now */
 786 }
 787
 788
 789 /*
 790  * implements the STARTTLS command (Citadel API version)
 791  */
 792 void smtp_starttls(void)
 793 {
 794         char ok_response[SIZ];
 795         char nosup_response[SIZ];
 796         char error_response[SIZ];
 797
 798         sprintf(ok_response,
 799                 "220 Begin TLS negotiation now\r\n");
 800         sprintf(nosup_response,
 801                 "554 TLS not supported here\r\n");
 802         sprintf(error_response,
 803                 "554 Internal error\r\n");
 804         CtdlModuleStartCryptoMsgs(ok_response, nosup_response, error_response);
 805         smtp_rset(0);
 806 }
 807
 808
 809
 810 /*
 811  * Main command loop for SMTP sessions.
 812  */
 813 void smtp_command_loop(void) {
 814         char cmdbuf[SIZ];
 815
 816         time(&CC->lastcmd);
 817         memset(cmdbuf, 0, sizeof cmdbuf); /* Clear it, just in case */
 818         if (client_getln(cmdbuf, sizeof cmdbuf) < 1) {
 819                 CtdlLogPrintf(CTDL_CRIT, "Client disconnected: ending session.\n");
 820                 CC->kill_me = 1;
 821                 return;
 822         }
 823         CtdlLogPrintf(CTDL_INFO, "SMTP server: %s\n", cmdbuf);
 824         while (strlen(cmdbuf) < 5) strcat(cmdbuf, " ");
 825
 826         if (SMTP->command_state == smtp_user) {
 827                 smtp_get_user(cmdbuf);
 828         }
 829
 830         else if (SMTP->command_state == smtp_password) {
 831                 smtp_get_pass(cmdbuf);
 832         }
 833
 834         else if (SMTP->command_state == smtp_plain) {
 835                 smtp_try_plain(cmdbuf);
 836         }
 837
 838         else if (!strncasecmp(cmdbuf, "AUTH", 4)) {
 839                 smtp_auth(&cmdbuf[5]);
 840         }
 841
 842         else if (!strncasecmp(cmdbuf, "DATA", 4)) {
 843                 smtp_data();
 844         }
 845
 846         else if (!strncasecmp(cmdbuf, "HELO", 4)) {
 847                 smtp_hello(&cmdbuf[5], 0);
 848         }
 849
 850         else if (!strncasecmp(cmdbuf, "EHLO", 4)) {
 851                 smtp_hello(&cmdbuf[5], 1);
 852         }
 853
 854         else if (!strncasecmp(cmdbuf, "LHLO", 4)) {
 855                 smtp_hello(&cmdbuf[5], 2);
 856         }
 857
 858         else if (!strncasecmp(cmdbuf, "HELP", 4)) {
 859                 smtp_help();
 860         }
 861
 862         else if (!strncasecmp(cmdbuf, "MAIL", 4)) {
 863                 smtp_mail(&cmdbuf[5]);
 864         }
 865
 866         else if (!strncasecmp(cmdbuf, "NOOP", 4)) {
 867                 cprintf("250 NOOP\r\n");
 868         }
 869
 870         else if (!strncasecmp(cmdbuf, "QUIT", 4)) {
 871                 cprintf("221 Goodbye...\r\n");
 872                 CC->kill_me = 1;
 873                 return;
 874         }
 875
 876         else if (!strncasecmp(cmdbuf, "RCPT", 4)) {
 877                 smtp_rcpt(&cmdbuf[5]);
 878         }
 879
 880         else if (!strncasecmp(cmdbuf, "RSET", 4)) {
 881                 smtp_rset(1);
 882         }
 883 #ifdef HAVE_OPENSSL
 884         else if (!strcasecmp(cmdbuf, "STARTTLS")) {
 885                 smtp_starttls();
 886         }
 887 #endif
 888         else {
 889                 cprintf("502 I'm afraid I can't do that.\r\n");
 890         }
 891
 892
 893 }
 894
 895
 896
 897
 898 /*****************************************************************************/
 899 /*               SMTP CLIENT (OUTBOUND PROCESSING) STUFF                     */
 900 /*****************************************************************************/
 901
 902
 903
 904 /*
 905  * smtp_try()
 906  *
 907  * Called by smtp_do_procmsg() to attempt delivery to one SMTP host
 908  *
 909  */
 910 void smtp_try(const char *key, const char *addr, int *status,
 911               char *dsn, size_t n, long msgnum)
 912 {
 913         int sock = (-1);
 914         char mxhosts[1024];
 915         int num_mxhosts;
 916         int mx;
 917         int i;
 918         char user[1024], node[1024], name[1024];
 919         char buf[1024];
 920         char mailfrom[1024];
 921         char mx_user[256];
 922         char mx_pass[256];
 923         char mx_host[256];
 924         char mx_port[256];
 925         int lp, rp;
 926         char *msgtext;
 927         char *ptr;
 928         size_t msg_size;
 929         int scan_done;
 930         char *nextline;
 931         char *chunk_to_send;
 932         char prev_char;
 933
 934
 935         /* Parse out the host portion of the recipient address */
 936         process_rfc822_addr(addr, user, node, name);
 937
 938         CtdlLogPrintf(CTDL_DEBUG, "SMTP client: Attempting delivery to <%s> @ <%s> (%s)\n",
 939                 user, node, name);
 940
 941         /* Load the message out of the database */
 942         CC->redirect_buffer = malloc(SIZ);
 943         CC->redirect_len = 0;
 944         CC->redirect_alloc = SIZ;
 945         CtdlOutputMsg(msgnum, MT_RFC822, HEADERS_ALL, 0, 1, NULL);
 946         msgtext = CC->redirect_buffer;
 947         msg_size = CC->redirect_len;
 948         CC->redirect_buffer = NULL;
 949         CC->redirect_len = 0;
 950         CC->redirect_alloc = 0;
 951
 952         /* Extract something to send later in the 'MAIL From:' command */
 953         strcpy(mailfrom, "");
 954         scan_done = 0;
 955         ptr = msgtext;
 956         do {
 957                 if (ptr = memreadline(ptr, buf, sizeof buf), *ptr == 0) {
 958                         scan_done = 1;
 959                 }
 960                 if (!strncasecmp(buf, "From:", 5)) {
 961                         safestrncpy(mailfrom, &buf[5], sizeof mailfrom);
 962                         striplt(mailfrom);
 963                         for (i=0; mailfrom[i]; ++i) {
 964                                 if (!isprint(mailfrom[i])) {
 965                                         strcpy(&mailfrom[i], &mailfrom[i+1]);
 966                                         i=0;
 967                                 }
 968                         }
 969
 970                         /* Strip out parenthesized names */
 971                         lp = (-1);
 972                         rp = (-1);
 973                         for (i=0; mailfrom[i]; ++i) {
 974                                 if (mailfrom[i] == '(') lp = i;
 975                                 if (mailfrom[i] == ')') rp = i;
 976                         }
 977                         if ((lp>0)&&(rp>lp)) {
 978                                 strcpy(&mailfrom[lp-1], &mailfrom[rp+1]);
 979                         }
 980
 981                         /* Prefer brokketized names */
 982                         lp = (-1);
 983                         rp = (-1);
 984                         for (i=0; mailfrom[i]; ++i) {
 985                                 if (mailfrom[i] == '<') lp = i;
 986                                 if (mailfrom[i] == '>') rp = i;
 987                         }
 988                         if ( (lp>=0) && (rp>lp) ) {
 989                                 mailfrom[rp] = 0;
 990                                 strcpy(mailfrom, &mailfrom[lp]);
 991                         }
 992
 993                         scan_done = 1;
 994                 }
 995         } while (scan_done == 0);
 996         if (IsEmptyStr(mailfrom)) strcpy(mailfrom, "someone@somewhere.org");
 997         stripallbut(mailfrom, '<', '>');
 998
 999         /* Figure out what mail exchanger host we have to connect to */
1000         num_mxhosts = getmx(mxhosts, node);
1001         CtdlLogPrintf(CTDL_DEBUG, "Number of MX hosts for <%s> is %d\n", node, num_mxhosts);
1002         if (num_mxhosts < 1) {
1003                 *status = 5;
1004                 snprintf(dsn, SIZ, "No MX hosts found for <%s>", node);
1005                 return;
1006         }
1007
1008         sock = (-1);
1009         for (mx=0; (mx<num_mxhosts && sock < 0); ++mx) {
1010                 char *endpart;
1011                 extract_token(buf, mxhosts, mx, '|', sizeof buf);
1012                 strcpy(mx_user, "");
1013                 strcpy(mx_pass, "");
1014                 if (num_tokens(buf, '@') > 1) {
1015                         strcpy (mx_user, buf);
1016                         endpart = strrchr(mx_user, '@');
1017                         *endpart = '\0';
1018                         strcpy (mx_host, endpart + 1);
1019                         endpart = strrchr(mx_user, ':');
1020                         if (endpart != NULL) {
1021                                 strcpy(mx_pass, endpart+1);
1022                                 *endpart = '\0';
1023                         }
1024                 }
1025                 else
1026                         strcpy (mx_host, buf);
1027                 endpart = strrchr(mx_host, ':');
1028                 if (endpart != 0){
1029                         *endpart = '\0';
1030                         strcpy(mx_port, endpart + 1);
1031                 }
1032                 else {
1033                         strcpy(mx_port, "25");
1034                 }
1035                 CtdlLogPrintf(CTDL_DEBUG, "SMTP client: connecting to %s : %s ...\n", mx_host, mx_port);
1036                 sock = sock_connect(mx_host, mx_port, "tcp");
1037                 snprintf(dsn, SIZ, "Could not connect: %s", strerror(errno));
1038                 if (sock >= 0) CtdlLogPrintf(CTDL_DEBUG, "SMTP client: connected!\n");
1039                 if (sock < 0) {
1040                         if (errno > 0) {
1041                                 snprintf(dsn, SIZ, "%s", strerror(errno));
1042                         }
1043                         else {
1044                                 snprintf(dsn, SIZ, "Unable to connect to %s : %s\n", mx_host, mx_port);
1045                         }
1046                 }
1047         }
1048
1049         if (sock < 0) {
1050                 *status = 4;    /* dsn is already filled in */
1051                 return;
1052         }
1053
1054         /* Process the SMTP greeting from the server */
1055         if (ml_sock_gets(sock, buf) < 0) {
1056                 *status = 4;
1057                 strcpy(dsn, "Connection broken during SMTP conversation");
1058                 goto bail;
1059         }
1060         CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1061         if (buf[0] != '2') {
1062                 if (buf[0] == '4') {
1063                         *status = 4;
1064                         safestrncpy(dsn, &buf[4], 1023);
1065                         goto bail;
1066                 }
1067                 else {
1068                         *status = 5;
1069                         safestrncpy(dsn, &buf[4], 1023);
1070                         goto bail;
1071                 }
1072         }
1073
1074         /* At this point we know we are talking to a real SMTP server */
1075
1076         /* Do a EHLO command.  If it fails, try the HELO command. */
1077         snprintf(buf, sizeof buf, "EHLO %s\r\n", config.c_fqdn);
1078         CtdlLogPrintf(CTDL_DEBUG, ">%s", buf);
1079         sock_write(sock, buf, strlen(buf));
1080         if (ml_sock_gets(sock, buf) < 0) {
1081                 *status = 4;
1082                 strcpy(dsn, "Connection broken during SMTP HELO");
1083                 goto bail;
1084         }
1085         CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1086         if (buf[0] != '2') {
1087                 snprintf(buf, sizeof buf, "HELO %s\r\n", config.c_fqdn);
1088                 CtdlLogPrintf(CTDL_DEBUG, ">%s", buf);
1089                 sock_write(sock, buf, strlen(buf));
1090                 if (ml_sock_gets(sock, buf) < 0) {
1091                         *status = 4;
1092                         strcpy(dsn, "Connection broken during SMTP HELO");
1093                         goto bail;
1094                 }
1095         }
1096         if (buf[0] != '2') {
1097                 if (buf[0] == '4') {
1098                         *status = 4;
1099                         safestrncpy(dsn, &buf[4], 1023);
1100                         goto bail;
1101                 }
1102                 else {
1103                         *status = 5;
1104                         safestrncpy(dsn, &buf[4], 1023);
1105                         goto bail;
1106                 }
1107         }
1108
1109         /* Do an AUTH command if necessary */
1110         if (!IsEmptyStr(mx_user)) {
1111                 char encoded[1024];
1112                 sprintf(buf, "%s%c%s%c%s", mx_user, '\0', mx_user, '\0', mx_pass);
1113                 CtdlEncodeBase64(encoded, buf, strlen(mx_user) + strlen(mx_user) + strlen(mx_pass) + 2, 0);
1114                 snprintf(buf, sizeof buf, "AUTH PLAIN %s\r\n", encoded);
1115                 CtdlLogPrintf(CTDL_DEBUG, ">%s", buf);
1116                 sock_write(sock, buf, strlen(buf));
1117                 if (ml_sock_gets(sock, buf) < 0) {
1118                         *status = 4;
1119                         strcpy(dsn, "Connection broken during SMTP AUTH");
1120                         goto bail;
1121                 }
1122                 CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1123                 if (buf[0] != '2') {
1124                         if (buf[0] == '4') {
1125                                 *status = 4;
1126                                 safestrncpy(dsn, &buf[4], 1023);
1127                                 goto bail;
1128                         }
1129                         else {
1130                                 *status = 5;
1131                                 safestrncpy(dsn, &buf[4], 1023);
1132                                 goto bail;
1133                         }
1134                 }
1135         }
1136
1137         /* previous command succeeded, now try the MAIL From: command */
1138         snprintf(buf, sizeof buf, "MAIL From: <%s>\r\n", mailfrom);
1139         CtdlLogPrintf(CTDL_DEBUG, ">%s", buf);
1140         sock_write(sock, buf, strlen(buf));
1141         if (ml_sock_gets(sock, buf) < 0) {
1142                 *status = 4;
1143                 strcpy(dsn, "Connection broken during SMTP MAIL");
1144                 goto bail;
1145         }
1146         CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1147         if (buf[0] != '2') {
1148                 if (buf[0] == '4') {
1149                         *status = 4;
1150                         safestrncpy(dsn, &buf[4], 1023);
1151                         goto bail;
1152                 }
1153                 else {
1154                         *status = 5;
1155                         safestrncpy(dsn, &buf[4], 1023);
1156                         goto bail;
1157                 }
1158         }
1159
1160         /* MAIL succeeded, now try the RCPT To: command */
1161         snprintf(buf, sizeof buf, "RCPT To: <%s@%s>\r\n", user, node);
1162         CtdlLogPrintf(CTDL_DEBUG, ">%s", buf);
1163         sock_write(sock, buf, strlen(buf));
1164         if (ml_sock_gets(sock, buf) < 0) {
1165                 *status = 4;
1166                 strcpy(dsn, "Connection broken during SMTP RCPT");
1167                 goto bail;
1168         }
1169         CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1170         if (buf[0] != '2') {
1171                 if (buf[0] == '4') {
1172                         *status = 4;
1173                         safestrncpy(dsn, &buf[4], 1023);
1174                         goto bail;
1175                 }
1176                 else {
1177                         *status = 5;
1178                         safestrncpy(dsn, &buf[4], 1023);
1179                         goto bail;
1180                 }
1181         }
1182
1183         /* RCPT succeeded, now try the DATA command */
1184         CtdlLogPrintf(CTDL_DEBUG, ">DATA\n");
1185         sock_write(sock, "DATA\r\n", 6);
1186         if (ml_sock_gets(sock, buf) < 0) {
1187                 *status = 4;
1188                 strcpy(dsn, "Connection broken during SMTP DATA");
1189                 goto bail;
1190         }
1191         CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1192         if (buf[0] != '3') {
1193                 if (buf[0] == '4') {
1194                         *status = 3;
1195                         safestrncpy(dsn, &buf[4], 1023);
1196                         goto bail;
1197                 }
1198                 else {
1199                         *status = 5;
1200                         safestrncpy(dsn, &buf[4], 1023);
1201                         goto bail;
1202                 }
1203         }
1204
1205         /* If we reach this point, the server is expecting data */
1206         /** Need to parse each line of the message here since someone may have sent
1207          * a message containing a single dot on a line of its own. In that case we
1208          * need to escape it in accordance with RFC821.
1209          * We could do this with the tokenizer functions but num_tokens returns an
1210          * int and the message may contain more lines than that, also copying each
1211          * line would be slow.
1212          */
1213         nextline = msgtext;
1214         while (*nextline)
1215         {
1216                 chunk_to_send = nextline;
1217                 while (*nextline != '\n')
1218                         nextline++;
1219                 nextline++;
1220                 prev_char = *nextline;
1221                 *nextline = '\0';
1222                 if (!strcmp(chunk_to_send, ".\r\n");
1223                         sock_write(sock, "..\r\n", 4);
1224                 else
1225                         sock_write(sock, chunk_to_send, (size_t)(nextline-chunk_to_send));
1226                 *nextline = prev_char;
1227         }
1228
1229         if (msgtext[msg_size-1] != 10) {
1230                 CtdlLogPrintf(CTDL_WARNING, "Possible problem: message did not "
1231                         "correctly terminate. (expecting 0x10, got 0x%02x)\n",
1232                                 buf[msg_size-1]);
1233         }
1234
1235         sock_write(sock, ".\r\n", 3);
1236         if (ml_sock_gets(sock, buf) < 0) {
1237                 *status = 4;
1238                 strcpy(dsn, "Connection broken during SMTP message transmit");
1239                 goto bail;
1240         }
1241         CtdlLogPrintf(CTDL_DEBUG, "%s\n", buf);
1242         if (buf[0] != '2') {
1243                 if (buf[0] == '4') {
1244                         *status = 4;
1245                         safestrncpy(dsn, &buf[4], 1023);
1246                         goto bail;
1247                 }
1248                 else {
1249                         *status = 5;
1250                         safestrncpy(dsn, &buf[4], 1023);
1251                         goto bail;
1252                 }
1253         }
1254
1255         /* We did it! */
1256         safestrncpy(dsn, &buf[4], 1023);
1257         *status = 2;
1258
1259         CtdlLogPrintf(CTDL_DEBUG, ">QUIT\n");
1260         sock_write(sock, "QUIT\r\n", 6);
1261         ml_sock_gets(sock, buf);
1262         CtdlLogPrintf(CTDL_DEBUG, "<%s\n", buf);
1263         CtdlLogPrintf(CTDL_INFO, "SMTP client: delivery to <%s> @ <%s> (%s) succeeded\n",
1264                 user, node, name);
1265
1266 bail:   free(msgtext);
1267         sock_close(sock);
1268
1269         /* Write something to the syslog (which may or may not be where the
1270          * rest of the Citadel logs are going; some sysadmins want LOG_MAIL).
1271          */
1272         if (enable_syslog) {
1273                 syslog((LOG_MAIL | LOG_INFO),
1274                         "%ld: to=<%s>, relay=%s, stat=%s",
1275                         msgnum,
1276                         addr,
1277                         mx_host,
1278                         dsn
1279                 );
1280         }
1281
1282         return;
1283 }
1284
1285
1286
1287 /*
1288  * smtp_do_bounce() is caled by smtp_do_procmsg() to scan a set of delivery
1289  * instructions for "5" codes (permanent fatal errors) and produce/deliver
1290  * a "bounce" message (delivery status notification).
1291  */
1292 void smtp_do_bounce(char *instr) {
1293         int i;
1294         int lines;
1295         int status;
1296         char buf[1024];
1297         char key[1024];
1298         char addr[1024];
1299         char dsn[1024];
1300         char bounceto[1024];
1301         char boundary[64];
1302         int num_bounces = 0;
1303         int bounce_this = 0;
1304         long bounce_msgid = (-1);
1305         time_t submitted = 0L;
1306         struct CtdlMessage *bmsg = NULL;
1307         int give_up = 0;
1308         struct recptypes *valid;
1309         int successful_bounce = 0;
1310         static int seq = 0;
1311         char *omsgtext;
1312         size_t omsgsize;
1313         long omsgid = (-1);
1314
1315         CtdlLogPrintf(CTDL_DEBUG, "smtp_do_bounce() called\n");
1316         strcpy(bounceto, "");
1317         sprintf(boundary, "=_Citadel_Multipart_%s_%04x%04x", config.c_fqdn, getpid(), ++seq);
1318         lines = num_tokens(instr, '\n');
1319
1320         /* See if it's time to give up on delivery of this message */
1321         for (i=0; i<lines; ++i) {
1322                 extract_token(buf, instr, i, '\n', sizeof buf);
1323                 extract_token(key, buf, 0, '|', sizeof key);
1324                 extract_token(addr, buf, 1, '|', sizeof addr);
1325                 if (!strcasecmp(key, "submitted")) {
1326                         submitted = atol(addr);
1327                 }
1328         }
1329
1330         if ( (time(NULL) - submitted) > SMTP_GIVE_UP ) {
1331                 give_up = 1;
1332         }
1333
1334         /* Start building our bounce message */
1335
1336         bmsg = (struct CtdlMessage *) malloc(sizeof(struct CtdlMessage));
1337         if (bmsg == NULL) return;
1338         memset(bmsg, 0, sizeof(struct CtdlMessage));
1339
1340         bmsg->cm_magic = CTDLMESSAGE_MAGIC;
1341         bmsg->cm_anon_type = MES_NORMAL;
1342         bmsg->cm_format_type = FMT_RFC822;
1343         bmsg->cm_fields['A'] = strdup("Citadel");
1344         bmsg->cm_fields['O'] = strdup(MAILROOM);
1345         bmsg->cm_fields['N'] = strdup(config.c_nodename);
1346         bmsg->cm_fields['U'] = strdup("Delivery Status Notification (Failure)");
1347         bmsg->cm_fields['M'] = malloc(1024);
1348
1349         strcpy(bmsg->cm_fields['M'], "Content-type: multipart/mixed; boundary=\"");
1350         strcat(bmsg->cm_fields['M'], boundary);
1351         strcat(bmsg->cm_fields['M'], "\"\r\n");
1352         strcat(bmsg->cm_fields['M'], "MIME-Version: 1.0\r\n");
1353         strcat(bmsg->cm_fields['M'], "X-Mailer: " CITADEL "\r\n");
1354         strcat(bmsg->cm_fields['M'], "\r\nThis is a multipart message in MIME format.\r\n\r\n");
1355         strcat(bmsg->cm_fields['M'], "--");
1356         strcat(bmsg->cm_fields['M'], boundary);
1357         strcat(bmsg->cm_fields['M'], "\r\n");
1358         strcat(bmsg->cm_fields['M'], "Content-type: text/plain\r\n\r\n");
1359
1360         if (give_up) strcat(bmsg->cm_fields['M'],
1361 "A message you sent could not be delivered to some or all of its recipients\n"
1362 "due to prolonged unavailability of its destination(s).\n"
1363 "Giving up on the following addresses:\n\n"
1364 );
1365
1366         else strcat(bmsg->cm_fields['M'],
1367 "A message you sent could not be delivered to some or all of its recipients.\n"
1368 "The following addresses were undeliverable:\n\n"
1369 );
1370
1371         /*
1372          * Now go through the instructions checking for stuff.
1373          */
1374         for (i=0; i<lines; ++i) {
1375                 extract_token(buf, instr, i, '\n', sizeof buf);
1376                 extract_token(key, buf, 0, '|', sizeof key);
1377                 extract_token(addr, buf, 1, '|', sizeof addr);
1378                 status = extract_int(buf, 2);
1379                 extract_token(dsn, buf, 3, '|', sizeof dsn);
1380                 bounce_this = 0;
1381
1382                 CtdlLogPrintf(CTDL_DEBUG, "key=<%s> addr=<%s> status=%d dsn=<%s>\n",
1383                         key, addr, status, dsn);
1384
1385                 if (!strcasecmp(key, "bounceto")) {
1386                         strcpy(bounceto, addr);
1387                 }
1388
1389                 if (!strcasecmp(key, "msgid")) {
1390                         omsgid = atol(addr);
1391                 }
1392
1393                 if (!strcasecmp(key, "remote")) {
1394                         if (status == 5) bounce_this = 1;
1395                         if (give_up) bounce_this = 1;
1396                 }
1397
1398                 if (bounce_this) {
1399                         ++num_bounces;
1400
1401                         if (bmsg->cm_fields['M'] == NULL) {
1402                                 CtdlLogPrintf(CTDL_ERR, "ERROR ... M field is null "
1403                                         "(%s:%d)\n", __FILE__, __LINE__);
1404                         }
1405
1406                         bmsg->cm_fields['M'] = realloc(bmsg->cm_fields['M'],
1407                                 strlen(bmsg->cm_fields['M']) + 1024 );
1408                         strcat(bmsg->cm_fields['M'], addr);
1409                         strcat(bmsg->cm_fields['M'], ": ");
1410                         strcat(bmsg->cm_fields['M'], dsn);
1411                         strcat(bmsg->cm_fields['M'], "\r\n");
1412
1413                         remove_token(instr, i, '\n');
1414                         --i;
1415                         --lines;
1416                 }
1417         }
1418
1419         /* Attach the original message */
1420         if (omsgid >= 0) {
1421                 strcat(bmsg->cm_fields['M'], "--");
1422                 strcat(bmsg->cm_fields['M'], boundary);
1423                 strcat(bmsg->cm_fields['M'], "\r\n");
1424                 strcat(bmsg->cm_fields['M'], "Content-type: message/rfc822\r\n");
1425                 strcat(bmsg->cm_fields['M'], "Content-Transfer-Encoding: 7bit\r\n");
1426                 strcat(bmsg->cm_fields['M'], "Content-Disposition: inline\r\n");
1427                 strcat(bmsg->cm_fields['M'], "\r\n");
1428
1429                 CC->redirect_buffer = malloc(SIZ);
1430                 CC->redirect_len = 0;
1431                 CC->redirect_alloc = SIZ;
1432                 CtdlOutputMsg(omsgid, MT_RFC822, HEADERS_ALL, 0, 1, NULL);
1433                 omsgtext = CC->redirect_buffer;
1434                 omsgsize = CC->redirect_len;
1435                 CC->redirect_buffer = NULL;
1436                 CC->redirect_len = 0;
1437                 CC->redirect_alloc = 0;
1438                 bmsg->cm_fields['M'] = realloc(bmsg->cm_fields['M'],
1439                                 (strlen(bmsg->cm_fields['M']) + omsgsize + 1024) );
1440                 strcat(bmsg->cm_fields['M'], omsgtext);
1441                 free(omsgtext);
1442         }
1443
1444         /* Close the multipart MIME scope */
1445         strcat(bmsg->cm_fields['M'], "--");
1446         strcat(bmsg->cm_fields['M'], boundary);
1447         strcat(bmsg->cm_fields['M'], "--\r\n");
1448
1449         /* Deliver the bounce if there's anything worth mentioning */
1450         CtdlLogPrintf(CTDL_DEBUG, "num_bounces = %d\n", num_bounces);
1451         if (num_bounces > 0) {
1452
1453                 /* First try the user who sent the message */
1454                 CtdlLogPrintf(CTDL_DEBUG, "bounce to user? <%s>\n", bounceto);
1455                 if (IsEmptyStr(bounceto)) {
1456                         CtdlLogPrintf(CTDL_ERR, "No bounce address specified\n");
1457                         bounce_msgid = (-1L);
1458                 }
1459
1460                 /* Can we deliver the bounce to the original sender? */
1461                 valid = validate_recipients(bounceto, smtp_get_Recipients (), 0);
1462                 if (valid != NULL) {
1463                         if (valid->num_error == 0) {
1464                                 CtdlSubmitMsg(bmsg, valid, "");
1465                                 successful_bounce = 1;
1466                         }
1467                 }
1468
1469                 /* If not, post it in the Aide> room */
1470                 if (successful_bounce == 0) {
1471                         CtdlSubmitMsg(bmsg, NULL, config.c_aideroom);
1472                 }
1473
1474                 /* Free up the memory we used */
1475                 if (valid != NULL) {
1476                         free_recipients(valid);
1477                 }
1478         }
1479
1480         CtdlFreeMessage(bmsg);
1481         CtdlLogPrintf(CTDL_DEBUG, "Done processing bounces\n");
1482 }
1483
1484
1485 /*
1486  * smtp_purge_completed_deliveries() is caled by smtp_do_procmsg() to scan a
1487  * set of delivery instructions for completed deliveries and remove them.
1488  *
1489  * It returns the number of incomplete deliveries remaining.
1490  */
1491 int smtp_purge_completed_deliveries(char *instr) {
1492         int i;
1493         int lines;
1494         int status;
1495         char buf[1024];
1496         char key[1024];
1497         char addr[1024];
1498         char dsn[1024];
1499         int completed;
1500         int incomplete = 0;
1501
1502         lines = num_tokens(instr, '\n');
1503         for (i=0; i<lines; ++i) {
1504                 extract_token(buf, instr, i, '\n', sizeof buf);
1505                 extract_token(key, buf, 0, '|', sizeof key);
1506                 extract_token(addr, buf, 1, '|', sizeof addr);
1507                 status = extract_int(buf, 2);
1508                 extract_token(dsn, buf, 3, '|', sizeof dsn);
1509
1510                 completed = 0;
1511
1512                 if (!strcasecmp(key, "remote")) {
1513                         if (status == 2) completed = 1;
1514                         else ++incomplete;
1515                 }
1516
1517                 if (completed) {
1518                         remove_token(instr, i, '\n');
1519                         --i;
1520                         --lines;
1521                 }
1522         }
1523
1524         return(incomplete);
1525 }
1526
1527
1528 /*
1529  * smtp_do_procmsg()
1530  *
1531  * Called by smtp_do_queue() to handle an individual message.
1532  */
1533 void smtp_do_procmsg(long msgnum, void *userdata) {
1534         struct CtdlMessage *msg = NULL;
1535         char *instr = NULL;
1536         char *results = NULL;
1537         int i;
1538         int lines;
1539         int status;
1540         char buf[1024];
1541         char key[1024];
1542         char addr[1024];
1543         char dsn[1024];
1544         long text_msgid = (-1);
1545         int incomplete_deliveries_remaining;
1546         time_t attempted = 0L;
1547         time_t last_attempted = 0L;
1548         time_t retry = SMTP_RETRY_INTERVAL;
1549
1550         CtdlLogPrintf(CTDL_DEBUG, "SMTP client: smtp_do_procmsg(%ld)\n", msgnum);
1551
1552         msg = CtdlFetchMessage(msgnum, 1);
1553         if (msg == NULL) {
1554                 CtdlLogPrintf(CTDL_ERR, "SMTP client: tried %ld but no such message!\n", msgnum);
1555                 return;
1556         }
1557
1558         instr = strdup(msg->cm_fields['M']);
1559         CtdlFreeMessage(msg);
1560
1561         /* Strip out the headers amd any other non-instruction line */
1562         lines = num_tokens(instr, '\n');
1563         for (i=0; i<lines; ++i) {
1564                 extract_token(buf, instr, i, '\n', sizeof buf);
1565                 if (num_tokens(buf, '|') < 2) {
1566                         remove_token(instr, i, '\n');
1567                         --lines;
1568                         --i;
1569                 }
1570         }
1571
1572         /* Learn the message ID and find out about recent delivery attempts */
1573         lines = num_tokens(instr, '\n');
1574         for (i=0; i<lines; ++i) {
1575                 extract_token(buf, instr, i, '\n', sizeof buf);
1576                 extract_token(key, buf, 0, '|', sizeof key);
1577                 if (!strcasecmp(key, "msgid")) {
1578                         text_msgid = extract_long(buf, 1);
1579                 }
1580                 if (!strcasecmp(key, "retry")) {
1581                         /* double the retry interval after each attempt */
1582                         retry = extract_long(buf, 1) * 2L;
1583                         if (retry > SMTP_RETRY_MAX) {
1584                                 retry = SMTP_RETRY_MAX;
1585                         }
1586                         remove_token(instr, i, '\n');
1587                 }
1588                 if (!strcasecmp(key, "attempted")) {
1589                         attempted = extract_long(buf, 1);
1590                         if (attempted > last_attempted)
1591                                 last_attempted = attempted;
1592                 }
1593         }
1594
1595         /*
1596          * Postpone delivery if we've already tried recently.
1597          */
1598         if (((time(NULL) - last_attempted) < retry) && (run_queue_now == 0)) {
1599                 CtdlLogPrintf(CTDL_DEBUG, "SMTP client: Retry time not yet reached.\n");
1600                 free(instr);
1601                 return;
1602         }
1603
1604
1605         /*
1606          * Bail out if there's no actual message associated with this
1607          */
1608         if (text_msgid < 0L) {
1609                 CtdlLogPrintf(CTDL_ERR, "SMTP client: no 'msgid' directive found!\n");
1610                 free(instr);
1611                 return;
1612         }
1613
1614         /* Plow through the instructions looking for 'remote' directives and
1615          * a status of 0 (no delivery yet attempted) or 3/4 (transient errors
1616          * were experienced and it's time to try again)
1617          */
1618         lines = num_tokens(instr, '\n');
1619         for (i=0; i<lines; ++i) {
1620                 extract_token(buf, instr, i, '\n', sizeof buf);
1621                 extract_token(key, buf, 0, '|', sizeof key);
1622                 extract_token(addr, buf, 1, '|', sizeof addr);
1623                 status = extract_int(buf, 2);
1624                 extract_token(dsn, buf, 3, '|', sizeof dsn);
1625                 if ( (!strcasecmp(key, "remote"))
1626                    && ((status==0)||(status==3)||(status==4)) ) {
1627
1628                         /* Remove this "remote" instruction from the set,
1629                          * but replace the set's final newline if
1630                          * remove_token() stripped it.  It has to be there.
1631                          */
1632                         remove_token(instr, i, '\n');
1633                         if (instr[strlen(instr)-1] != '\n') {
1634                                 strcat(instr, "\n");
1635                         }
1636
1637                         --i;
1638                         --lines;
1639                         CtdlLogPrintf(CTDL_DEBUG, "SMTP client: Trying <%s>\n", addr);
1640                         smtp_try(key, addr, &status, dsn, sizeof dsn, text_msgid);
1641                         if (status != 2) {
1642                                 if (results == NULL) {
1643                                         results = malloc(1024);
1644                                         memset(results, 0, 1024);
1645                                 }
1646                                 else {
1647                                         results = realloc(results, strlen(results) + 1024);
1648                                 }
1649                                 snprintf(&results[strlen(results)], 1024,
1650                                         "%s|%s|%d|%s\n",
1651                                         key, addr, status, dsn);
1652                         }
1653                 }
1654         }
1655
1656         if (results != NULL) {
1657                 instr = realloc(instr, strlen(instr) + strlen(results) + 2);
1658                 strcat(instr, results);
1659                 free(results);
1660         }
1661
1662
1663         /* Generate 'bounce' messages */
1664         smtp_do_bounce(instr);
1665
1666         /* Go through the delivery list, deleting completed deliveries */
1667         incomplete_deliveries_remaining =
1668                 smtp_purge_completed_deliveries(instr);
1669
1670
1671         /*
1672          * No delivery instructions remain, so delete both the instructions
1673          * message and the message message.
1674          */
1675         if (incomplete_deliveries_remaining <= 0) {
1676                 long delmsgs[2];
1677                 delmsgs[0] = msgnum;
1678                 delmsgs[1] = text_msgid;
1679                 CtdlDeleteMessages(SMTP_SPOOLOUT_ROOM, delmsgs, 2, "");
1680         }
1681
1682         /*
1683          * Uncompleted delivery instructions remain, so delete the old
1684          * instructions and replace with the updated ones.
1685          */
1686         if (incomplete_deliveries_remaining > 0) {
1687                 CtdlDeleteMessages(SMTP_SPOOLOUT_ROOM, &msgnum, 1, "");
1688                 msg = malloc(sizeof(struct CtdlMessage));
1689                 memset(msg, 0, sizeof(struct CtdlMessage));
1690                 msg->cm_magic = CTDLMESSAGE_MAGIC;
1691                 msg->cm_anon_type = MES_NORMAL;
1692                 msg->cm_format_type = FMT_RFC822;
1693                 msg->cm_fields['M'] = malloc(strlen(instr)+SIZ);
1694                 snprintf(msg->cm_fields['M'],
1695                         strlen(instr)+SIZ,
1696                         "Content-type: %s\n\n%s\n"
1697                         "attempted|%ld\n"
1698                         "retry|%ld\n",
1699                         SPOOLMIME, instr, (long)time(NULL), (long)retry );
1700                 CtdlSubmitMsg(msg, NULL, SMTP_SPOOLOUT_ROOM);
1701                 CtdlFreeMessage(msg);
1702         }
1703
1704         free(instr);
1705 }
1706
1707
1708
1709 /*
1710  * smtp_do_queue()
1711  *
1712  * Run through the queue sending out messages.
1713  */
1714 void smtp_do_queue(void) {
1715         static int doing_queue = 0;
1716
1717         /*
1718          * This is a simple concurrency check to make sure only one queue run
1719          * is done at a time.  We could do this with a mutex, but since we
1720          * don't really require extremely fine granularity here, we'll do it
1721          * with a static variable instead.
1722          */
1723         if (doing_queue) return;
1724         doing_queue = 1;
1725
1726         /*
1727          * Go ahead and run the queue
1728          */
1729         CtdlLogPrintf(CTDL_INFO, "SMTP client: processing outbound queue\n");
1730
1731         if (getroom(&CC->room, SMTP_SPOOLOUT_ROOM) != 0) {
1732                 CtdlLogPrintf(CTDL_ERR, "Cannot find room <%s>\n", SMTP_SPOOLOUT_ROOM);
1733                 return;
1734         }
1735         CtdlForEachMessage(MSGS_ALL, 0L, NULL,
1736                 SPOOLMIME, NULL, smtp_do_procmsg, NULL);
1737
1738         CtdlLogPrintf(CTDL_INFO, "SMTP client: queue run completed\n");
1739         run_queue_now = 0;
1740         doing_queue = 0;
1741 }
1742
1743
1744
1745 /*****************************************************************************/
1746 /*                          SMTP UTILITY COMMANDS                            */
1747 /*****************************************************************************/
1748
1749 void cmd_smtp(char *argbuf) {
1750         char cmd[64];
1751         char node[256];
1752         char buf[1024];
1753         int i;
1754         int num_mxhosts;
1755
1756         if (CtdlAccessCheck(ac_aide)) return;
1757
1758         extract_token(cmd, argbuf, 0, '|', sizeof cmd);
1759
1760         if (!strcasecmp(cmd, "mx")) {
1761                 extract_token(node, argbuf, 1, '|', sizeof node);
1762                 num_mxhosts = getmx(buf, node);
1763                 cprintf("%d %d MX hosts listed for %s\n",
1764                         LISTING_FOLLOWS, num_mxhosts, node);
1765                 for (i=0; i<num_mxhosts; ++i) {
1766                         extract_token(node, buf, i, '|', sizeof node);
1767                         cprintf("%s\n", node);
1768                 }
1769                 cprintf("000\n");
1770                 return;
1771         }
1772
1773         else if (!strcasecmp(cmd, "runqueue")) {
1774                 run_queue_now = 1;
1775                 cprintf("%d All outbound SMTP will be retried now.\n", CIT_OK);
1776                 return;
1777         }
1778
1779         else {
1780                 cprintf("%d Invalid command.\n", ERROR + ILLEGAL_VALUE);
1781         }
1782
1783 }
1784
1785
1786 /*
1787  * Initialize the SMTP outbound queue
1788  */
1789 void smtp_init_spoolout(void) {
1790         struct ctdlroom qrbuf;
1791
1792         /*
1793          * Create the room.  This will silently fail if the room already
1794          * exists, and that's perfectly ok, because we want it to exist.
1795          */
1796         create_room(SMTP_SPOOLOUT_ROOM, 3, "", 0, 1, 0, VIEW_MAILBOX);
1797
1798         /*
1799          * Make sure it's set to be a "system room" so it doesn't show up
1800          * in the <K>nown rooms list for Aides.
1801          */
1802         if (lgetroom(&qrbuf, SMTP_SPOOLOUT_ROOM) == 0) {
1803                 qrbuf.QRflags2 |= QR2_SYSTEM;
1804                 lputroom(&qrbuf);
1805         }
1806 }
1807
1808
1809
1810
1811 /*****************************************************************************/
1812 /*                      MODULE INITIALIZATION STUFF                          */
1813 /*****************************************************************************/
1814 /*
1815  * This cleanup function blows away the temporary memory used by
1816  * the SMTP server.
1817  */
1818 void smtp_cleanup_function(void) {
1819
1820         /* Don't do this stuff if this is not an SMTP session! */
1821         if (CC->h_command_function != smtp_command_loop) return;
1822
1823         CtdlLogPrintf(CTDL_DEBUG, "Performing SMTP cleanup hook\n");
1824         free(SMTP);
1825 }
1826
1827
1828
1829 const char *CitadelServiceSMTP_MTA="SMTP-MTA";
1830 const char *CitadelServiceSMTPS_MTA="SMTPs-MTA";
1831 const char *CitadelServiceSMTP_MSA="SMTP-MSA";
1832 const char *CitadelServiceSMTP_LMTP="LMTP";
1833 const char *CitadelServiceSMTP_LMTP_UNF="LMTP-UnF";
1834
1835 CTDL_MODULE_INIT(smtp)
1836 {
1837         if (!threading)
1838         {
1839                 CtdlRegisterServiceHook(config.c_smtp_port,     /* SMTP MTA */
1840                                         NULL,
1841                                         smtp_mta_greeting,
1842                                         smtp_command_loop,
1843                                         NULL,
1844                                         CitadelServiceSMTP_MTA);
1845
1846 #ifdef HAVE_OPENSSL
1847                 CtdlRegisterServiceHook(config.c_smtps_port,
1848                                         NULL,
1849                                         smtps_greeting,
1850                                         smtp_command_loop,
1851                                         NULL,
1852                                         CitadelServiceSMTPS_MTA);
1853 #endif
1854
1855                 CtdlRegisterServiceHook(config.c_msa_port,      /* SMTP MSA */
1856                                         NULL,
1857                                         smtp_msa_greeting,
1858                                         smtp_command_loop,
1859                                         NULL,
1860                                         CitadelServiceSMTP_MSA);
1861
1862                 CtdlRegisterServiceHook(0,                      /* local LMTP */
1863                                         file_lmtp_socket,
1864                                         lmtp_greeting,
1865                                         smtp_command_loop,
1866                                         NULL,
1867                                         CitadelServiceSMTP_LMTP);
1868
1869                 CtdlRegisterServiceHook(0,                      /* local LMTP */
1870                                         file_lmtp_unfiltered_socket,
1871                                         lmtp_unfiltered_greeting,
1872                                         smtp_command_loop,
1873                                         NULL,
1874                                         CitadelServiceSMTP_LMTP_UNF);
1875
1876                 smtp_init_spoolout();
1877                 CtdlRegisterSessionHook(smtp_do_queue, EVT_TIMER);
1878                 CtdlRegisterSessionHook(smtp_cleanup_function, EVT_STOP);
1879                 CtdlRegisterProtoHook(cmd_smtp, "SMTP", "SMTP utility commands");
1880         }
1881
1882         /* return our Subversion id for the Log */
1883         return "$Id$";
1884 }