citadel/serv_smtp.c

   1 /* $Id$ */
   2
   3 #define SMTP_PORT       2525
   4
   5 #include "sysdep.h"
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <stdio.h>
   9 #include <fcntl.h>
  10 #include <signal.h>
  11 #include <pwd.h>
  12 #include <errno.h>
  13 #include <sys/types.h>
  14 #include <sys/time.h>
  15 #include <sys/wait.h>
  16 #include <string.h>
  17 #include <limits.h>
  18 #include "citadel.h"
  19 #include "server.h"
  20 #include <time.h>
  21 #include "sysdep_decls.h"
  22 #include "citserver.h"
  23 #include "support.h"
  24 #include "config.h"
  25 #include "dynloader.h"
  26 #include "room_ops.h"
  27 #include "user_ops.h"
  28 #include "policy.h"
  29 #include "database.h"
  30 #include "msgbase.h"
  31 #include "tools.h"
  32 #include "internet_addressing.h"
  33
  34
  35 struct citsmtp {                /* Information about the current session */
  36         int command_state;
  37         struct usersupp vrfy_buffer;
  38         int vrfy_count;
  39         char vrfy_match[256];
  40         char from[256];
  41         char recipient[256];
  42         int number_of_recipients;
  43 };
  44
  45 enum {                          /* Command states for login authentication */
  46         smtp_command,
  47         smtp_user,
  48         smtp_password
  49 };
  50
  51 #define SMTP ((struct citsmtp *)CtdlGetUserData(SYM_SMTP))
  52
  53 long SYM_SMTP;
  54
  55
  56 /*
  57  * Here's where our SMTP session begins its happy day.
  58  */
  59 void smtp_greeting(void) {
  60
  61         strcpy(CC->cs_clientname, "SMTP session");
  62         CC->internal_pgm = 1;
  63         CC->cs_flags |= CS_STEALTH;
  64         CtdlAllocUserData(SYM_SMTP, sizeof(struct citsmtp));
  65
  66         cprintf("220 Welcome to the Citadel/UX ESMTP server at %s\n",
  67                 config.c_fqdn);
  68 }
  69
  70
  71 /*
  72  * Implement HELO and EHLO commands.
  73  */
  74 void smtp_hello(char *argbuf, int is_esmtp) {
  75
  76         if (!is_esmtp) {
  77                 cprintf("250 Greetings and joyous salutations.\n");
  78         }
  79         else {
  80                 cprintf("250-Greetings and joyous salutations.\n");
  81                 cprintf("250-HELP\n");
  82                 cprintf("250-SIZE %ld\n", config.c_maxmsglen);
  83                 cprintf("250 AUTH=LOGIN\n");
  84         }
  85 }
  86
  87
  88 /*
  89  * Implement HELP command.
  90  */
  91 void smtp_help(void) {
  92         cprintf("214-Here's the frequency, Kenneth:\n");
  93         cprintf("214-    DATA\n");
  94         cprintf("214-    EHLO\n");
  95         cprintf("214-    EXPN\n");
  96         cprintf("214-    HELO\n");
  97         cprintf("214-    HELP\n");
  98         cprintf("214-    MAIL\n");
  99         cprintf("214-    NOOP\n");
 100         cprintf("214-    QUIT\n");
 101         cprintf("214-    RCPT\n");
 102         cprintf("214-    RSET\n");
 103         cprintf("214-    VRFY\n");
 104         cprintf("214 I could tell you more, but then I'd have to kill you.\n");
 105 }
 106
 107
 108 /*
 109  *
 110  */
 111 void smtp_get_user(char *argbuf) {
 112         char buf[256];
 113         char username[256];
 114
 115         decode_base64(username, argbuf);
 116         lprintf(9, "Trying <%s>\n", username);
 117         if (CtdlLoginExistingUser(username) == login_ok) {
 118                 encode_base64(buf, "Password:");
 119                 cprintf("334 %s\n", buf);
 120                 SMTP->command_state = smtp_password;
 121         }
 122         else {
 123                 cprintf("500 No such user.\n");
 124                 SMTP->command_state = smtp_command;
 125         }
 126 }
 127
 128
 129 /*
 130  *
 131  */
 132 void smtp_get_pass(char *argbuf) {
 133         char password[256];
 134
 135         decode_base64(password, argbuf);
 136         lprintf(9, "Trying <%s>\n", password);
 137         if (CtdlTryPassword(password) == pass_ok) {
 138                 cprintf("235 Authentication successful.\n");
 139                 lprintf(9, "SMTP auth login successful\n");
 140                 CC->internal_pgm = 0;
 141                 CC->cs_flags &= ~CS_STEALTH;
 142         }
 143         else {
 144                 cprintf("500 Authentication failed.\n");
 145         }
 146         SMTP->command_state = smtp_command;
 147 }
 148
 149
 150 /*
 151  *
 152  */
 153 void smtp_auth(char *argbuf) {
 154         char buf[256];
 155
 156         if (strncasecmp(argbuf, "login", 5) ) {
 157                 cprintf("550 We only support LOGIN authentication.\n");
 158                 return;
 159         }
 160
 161         if (strlen(argbuf) >= 7) {
 162                 smtp_get_user(&argbuf[6]);
 163         }
 164
 165         else {
 166                 encode_base64(buf, "Username:");
 167                 cprintf("334 %s\n", buf);
 168                 SMTP->command_state = smtp_user;
 169         }
 170 }
 171
 172
 173 /*
 174  * Back end for smtp_vrfy() command
 175  */
 176 void smtp_vrfy_backend(struct usersupp *us) {
 177
 178         if (!fuzzy_match(us, SMTP->vrfy_match)) {
 179                 ++SMTP->vrfy_count;
 180                 memcpy(&SMTP->vrfy_buffer, us, sizeof(struct usersupp));
 181         }
 182 }
 183
 184
 185 /*
 186  * Implements the VRFY (verify user name) command.
 187  * Performs fuzzy match on full user names.
 188  */
 189 void smtp_vrfy(char *argbuf) {
 190         SMTP->vrfy_count = 0;
 191         strcpy(SMTP->vrfy_match, argbuf);
 192         ForEachUser(smtp_vrfy_backend);
 193
 194         if (SMTP->vrfy_count < 1) {
 195                 cprintf("550 String does not match anything.\n");
 196         }
 197         else if (SMTP->vrfy_count == 1) {
 198                 cprintf("250 %s <cit%ld@%s>\n",
 199                         SMTP->vrfy_buffer.fullname,
 200                         SMTP->vrfy_buffer.usernum,
 201                         config.c_fqdn);
 202         }
 203         else if (SMTP->vrfy_count > 1) {
 204                 cprintf("553 Request ambiguous: %d users matched.\n",
 205                         SMTP->vrfy_count);
 206         }
 207
 208 }
 209
 210
 211
 212 /*
 213  * Back end for smtp_expn() command
 214  */
 215 void smtp_expn_backend(struct usersupp *us) {
 216
 217         if (!fuzzy_match(us, SMTP->vrfy_match)) {
 218
 219                 if (SMTP->vrfy_count >= 1) {
 220                         cprintf("250-%s <cit%ld@%s>\n",
 221                                 SMTP->vrfy_buffer.fullname,
 222                                 SMTP->vrfy_buffer.usernum,
 223                                 config.c_fqdn);
 224                 }
 225
 226                 ++SMTP->vrfy_count;
 227                 memcpy(&SMTP->vrfy_buffer, us, sizeof(struct usersupp));
 228         }
 229 }
 230
 231
 232 /*
 233  * Implements the EXPN (expand user name) command.
 234  * Performs fuzzy match on full user names.
 235  */
 236 void smtp_expn(char *argbuf) {
 237         SMTP->vrfy_count = 0;
 238         strcpy(SMTP->vrfy_match, argbuf);
 239         ForEachUser(smtp_expn_backend);
 240
 241         if (SMTP->vrfy_count < 1) {
 242                 cprintf("550 String does not match anything.\n");
 243         }
 244         else if (SMTP->vrfy_count >= 1) {
 245                 cprintf("250 %s <cit%ld@%s>\n",
 246                         SMTP->vrfy_buffer.fullname,
 247                         SMTP->vrfy_buffer.usernum,
 248                         config.c_fqdn);
 249         }
 250 }
 251
 252
 253 /*
 254  * Implements the RSET (reset state) command.
 255  * Currently this just zeroes out the state buffer.  If pointers to data
 256  * allocated with mallok() are ever placed in the state buffer, we have to
 257  * be sure to phree() them first!
 258  */
 259 void smtp_rset(void) {
 260         memset(SMTP, 0, sizeof(struct citsmtp));
 261         if (CC->logged_in) logout(CC);
 262         cprintf("250 Zap!\n");
 263 }
 264
 265
 266
 267 /*
 268  * Implements the "MAIL From:" command
 269  */
 270 void smtp_mail(char *argbuf) {
 271         char user[256];
 272         char node[256];
 273         int cvt;
 274
 275         if (strlen(SMTP->from) != 0) {
 276                 cprintf("503 Only one sender permitted\n");
 277                 return;
 278         }
 279
 280         if (strncasecmp(argbuf, "From:", 5)) {
 281                 cprintf("501 Syntax error\n");
 282                 return;
 283         }
 284
 285         strcpy(SMTP->from, &argbuf[5]);
 286         striplt(SMTP->from);
 287
 288         if (strlen(SMTP->from) == 0) {
 289                 cprintf("501 Empty sender name is not permitted\n");
 290                 return;
 291         }
 292
 293
 294         /* If this SMTP connection is from a logged-in user, make sure that
 295          * the user only sends email from his/her own address.
 296          */
 297         if (CC->logged_in) {
 298                 cvt = convert_internet_address(user, node, SMTP->from);
 299                 lprintf(9, "cvt=%d, citaddr=<%s@%s>\n", cvt, user, node);
 300                 if ( (cvt != 0) || (strcasecmp(user, CC->usersupp.fullname))) {
 301                         cprintf("550 <%s> is not your address.\n", SMTP->from);
 302                         strcpy(SMTP->from, "");
 303                         return;
 304                 }
 305         }
 306
 307         /* Otherwise, make sure outsiders aren't trying to forge mail from
 308          * this system.
 309          */
 310         else {
 311                 cvt = convert_internet_address(user, node, SMTP->from);
 312                 lprintf(9, "cvt=%d, citaddr=<%s@%s>\n", cvt, user, node);
 313                 if (!strcasecmp(node, config.c_nodename)) { /* FIX use fcn */
 314                         cprintf("550 You must log in to send mail from %s\n",
 315                                 config.c_fqdn);
 316                         strcpy(SMTP->from, "");
 317                         return;
 318                 }
 319         }
 320
 321         cprintf("250 Sender ok.  Groovy.\n");
 322 }
 323
 324
 325
 326 /*
 327  * Implements the "RCPT To:" command
 328  */
 329 void smtp_rcpt(char *argbuf) {
 330         int cvt;
 331         char user[256];
 332         char node[256];
 333
 334         if (strlen(SMTP->from) == 0) {
 335                 cprintf("503 MAIL first, then RCPT.  Duh.\n");
 336                 return;
 337         }
 338
 339         if (SMTP->number_of_recipients > 0) {
 340                 cprintf("552 Only one recipient allowed (FIX)\n");
 341                 return;
 342         }
 343
 344         if (strncasecmp(argbuf, "To:", 3)) {
 345                 cprintf("501 Syntax error\n");
 346                 return;
 347         }
 348
 349         strcpy(SMTP->recipient, &argbuf[3]);
 350         striplt(SMTP->recipient);
 351
 352         cvt = convert_internet_address(user, node, SMTP->recipient);
 353         switch(cvt) {
 354                 case rfc822_address_locally_validated:
 355                         cprintf("250 %s is a valid recipient.\n", user);
 356                         ++SMTP->number_of_recipients;
 357                         return;
 358                 case rfc822_no_such_user:
 359                         cprintf("550 %s: no such user\n", SMTP->recipient);
 360                         strcpy(SMTP->recipient, "");
 361                         return;
 362         }
 363
 364         strcpy(SMTP->recipient, "");
 365         cprintf("599 Unknown error (FIX)\n");
 366 }
 367
 368
 369
 370
 371
 372 /*
 373  * Back end for smtp_data()  ... this does the actual delivery of the message
 374  * Returns 0 on success, nonzero on failure
 375  */
 376 int smtp_message_delivery(struct CtdlMessage *msg) {
 377         char user[256];
 378         char node[256];
 379         char name[256];
 380         int successful_saves = 0;
 381         int failed_saves = 0;
 382         long msgid = (-1L);
 383         int cvt;
 384
 385         lprintf(9, "smtp_message_delivery() called\n");
 386
 387         /* Fill in 'from' fields with envelope information if missing */
 388         process_rfc822_addr(SMTP->from, user, node, name);
 389         if (msg->cm_fields['A']==NULL) msg->cm_fields['A'] = strdoop(user);
 390         if (msg->cm_fields['N']==NULL) msg->cm_fields['N'] = strdoop(node);
 391         if (msg->cm_fields['H']==NULL) msg->cm_fields['H'] = strdoop(name);
 392
 393         /* Stuff the boxes */
 394         /* FIX modify to handle multiple recipients */
 395         cvt = convert_internet_address(user, node, SMTP->recipient);
 396         switch(cvt) {
 397                 case rfc822_address_locally_validated:
 398                         lprintf(9, "Delivering to %s\n", user);
 399
 400                         if (msgid < 0L) {
 401                                 CtdlSaveMsg(msg,
 402                                         user,
 403                                         "",
 404                                         MES_LOCAL,
 405                                         1);
 406                         }
 407                         else {
 408                                 /* FIX copy the msgid to another room */
 409                         }
 410
 411                         ++successful_saves;
 412                         break;
 413
 414                 case rfc822_no_such_user:
 415                         ++failed_saves;
 416                         break;
 417         }
 418
 419         return(failed_saves);
 420 }
 421
 422
 423
 424 /*
 425  * Implements the DATA command
 426  */
 427 void smtp_data(void) {
 428         char *body;
 429         struct CtdlMessage *msg;
 430         int retval;
 431
 432         if (strlen(SMTP->from) == 0) {
 433                 cprintf("503 Need MAIL command first.\n");
 434                 return;
 435         }
 436
 437         if (SMTP->number_of_recipients < 1) {
 438                 cprintf("503 Need RCPT command first.\n");
 439                 return;
 440         }
 441
 442         cprintf("354 Transmit message now; terminate with '.' by itself\n");
 443         body = CtdlReadMessageBody(".", config.c_maxmsglen);
 444         if (body == NULL) {
 445                 cprintf("550 Unable to save message text: internal error.\n");
 446                 return;
 447         }
 448
 449         lprintf(9, "Converting message...\n");
 450         msg = convert_internet_message(body);
 451
 452         /* If the user is locally authenticated, FORCE the From: header to
 453          * show up as the real sender
 454          */
 455         if (CC->logged_in) {
 456                 if (msg->cm_fields['A'] != NULL) phree(msg->cm_fields['A']);
 457                 if (msg->cm_fields['N'] != NULL) phree(msg->cm_fields['N']);
 458                 if (msg->cm_fields['H'] != NULL) phree(msg->cm_fields['H']);
 459                 msg->cm_fields['A'] = strdoop(CC->usersupp.fullname);
 460                 msg->cm_fields['N'] = strdoop(config.c_nodename);
 461                 msg->cm_fields['H'] = strdoop(config.c_humannode);
 462         }
 463
 464         retval = smtp_message_delivery(msg);
 465         CtdlFreeMessage(msg);
 466
 467         if (!retval) {
 468                 cprintf("250 Message accepted for delivery.\n");
 469         }
 470         else {
 471                 cprintf("550 Internal error.\n");
 472         }
 473 }
 474
 475
 476
 477
 478 /*
 479  * Main command loop for SMTP sessions.
 480  */
 481 void smtp_command_loop(void) {
 482         char cmdbuf[256];
 483
 484         time(&CC->lastcmd);
 485         memset(cmdbuf, 0, sizeof cmdbuf); /* Clear it, just in case */
 486         if (client_gets(cmdbuf) < 1) {
 487                 lprintf(3, "SMTP socket is broken.  Ending session.\n");
 488                 CC->kill_me = 1;
 489                 return;
 490         }
 491         lprintf(5, "citserver[%3d]: %s\n", CC->cs_pid, cmdbuf);
 492         while (strlen(cmdbuf) < 5) strcat(cmdbuf, " ");
 493
 494         if (SMTP->command_state == smtp_user) {
 495                 smtp_get_user(cmdbuf);
 496         }
 497
 498         else if (SMTP->command_state == smtp_password) {
 499                 smtp_get_pass(cmdbuf);
 500         }
 501
 502         else if (!strncasecmp(cmdbuf, "AUTH", 4)) {
 503                 smtp_auth(&cmdbuf[5]);
 504         }
 505
 506         else if (!strncasecmp(cmdbuf, "DATA", 4)) {
 507                 smtp_data();
 508         }
 509
 510         else if (!strncasecmp(cmdbuf, "EHLO", 4)) {
 511                 smtp_hello(&cmdbuf[5], 1);
 512         }
 513
 514         else if (!strncasecmp(cmdbuf, "EXPN", 4)) {
 515                 smtp_expn(&cmdbuf[5]);
 516         }
 517
 518         else if (!strncasecmp(cmdbuf, "HELO", 4)) {
 519                 smtp_hello(&cmdbuf[5], 0);
 520         }
 521
 522         else if (!strncasecmp(cmdbuf, "HELP", 4)) {
 523                 smtp_help();
 524         }
 525
 526         else if (!strncasecmp(cmdbuf, "MAIL", 4)) {
 527                 smtp_mail(&cmdbuf[5]);
 528         }
 529
 530         else if (!strncasecmp(cmdbuf, "NOOP", 4)) {
 531                 cprintf("250 This command successfully did nothing.\n");
 532         }
 533
 534         else if (!strncasecmp(cmdbuf, "QUIT", 4)) {
 535                 cprintf("221 Goodbye...\n");
 536                 CC->kill_me = 1;
 537                 return;
 538                 }
 539
 540         else if (!strncasecmp(cmdbuf, "RCPT", 4)) {
 541                 smtp_rcpt(&cmdbuf[5]);
 542         }
 543
 544         else if (!strncasecmp(cmdbuf, "RSET", 4)) {
 545                 smtp_rset();
 546         }
 547
 548         else if (!strncasecmp(cmdbuf, "VRFY", 4)) {
 549                 smtp_vrfy(&cmdbuf[5]);
 550         }
 551
 552         else {
 553                 cprintf("502 I'm afraid I can't do that, Dave.\n");
 554         }
 555
 556 }
 557
 558
 559
 560 char *Dynamic_Module_Init(void)
 561 {
 562         SYM_SMTP = CtdlGetDynamicSymbol();
 563         CtdlRegisterServiceHook(SMTP_PORT,
 564                                 smtp_greeting,
 565                                 smtp_command_loop);
 566         return "$Id$";
 567 }