citadel/modules/smtp/smtp_util.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  * The VRFY and EXPN commands have been removed from this implementation
  21  * because nobody uses these commands anymore, except for spammers.
  22  *
  23  * Copyright (c) 1998-2012 by the citadel.org team
  24  *
  25  *  This program is open source software; you can redistribute it and/or modify
  26  *  it under the terms of the GNU General Public License version 3.
  27  *
  28  *
  29  *
  30  *  This program is distributed in the hope that it will be useful,
  31  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  32  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  33  *  GNU General Public License for more details.
  34  *
  35  *
  36  *
  37  *
  38  */
  39
  40 #include "sysdep.h"
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43 #include <stdio.h>
  44 #include <termios.h>
  45 #include <fcntl.h>
  46 #include <signal.h>
  47 #include <pwd.h>
  48 #include <errno.h>
  49 #include <sys/types.h>
  50 #include <syslog.h>
  51
  52 #if TIME_WITH_SYS_TIME
  53 # include <sys/time.h>
  54 # include <time.h>
  55 #else
  56 # if HAVE_SYS_TIME_H
  57 #  include <sys/time.h>
  58 # else
  59 #  include <time.h>
  60 # endif
  61 #endif
  62
  63 #include <sys/wait.h>
  64 #include <ctype.h>
  65 #include <string.h>
  66 #include <limits.h>
  67 #include <sys/socket.h>
  68 #include <netinet/in.h>
  69 #include <arpa/inet.h>
  70 #include <libcitadel.h>
  71 #include "citadel.h"
  72 #include "server.h"
  73 #include "citserver.h"
  74 #include "support.h"
  75 #include "config.h"
  76 #include "control.h"
  77 #include "user_ops.h"
  78 #include "database.h"
  79 #include "msgbase.h"
  80 #include "internet_addressing.h"
  81 #include "genstamp.h"
  82 #include "domain.h"
  83 #include "clientsocket.h"
  84 #include "locate_host.h"
  85 #include "citadel_dirs.h"
  86
  87 #include "ctdl_module.h"
  88
  89 #include "smtp_util.h"
  90
  91 const char *smtp_get_Recipients(void)
  92 {
  93         citsmtp *sSMTP = SMTP;
  94
  95         if (sSMTP == NULL)
  96                 return NULL;
  97         else return ChrPtr(sSMTP->from);
  98 }
  99
 100
 101 /*
 102  * smtp_do_bounce() is caled by smtp_do_procmsg() to scan a set of delivery
 103  * instructions for "5" codes (permanent fatal errors) and produce/deliver
 104  * a "bounce" message (delivery status notification).
 105  */
 106 void smtp_do_bounce(char *instr, StrBuf *OMsgTxt)
 107 {
 108         int i;
 109         int lines;
 110         int status;
 111         char buf[1024];
 112         char key[1024];
 113         char addr[1024];
 114         char dsn[1024];
 115         char bounceto[1024];
 116         StrBuf *boundary;
 117         int num_bounces = 0;
 118         int bounce_this = 0;
 119         time_t submitted = 0L;
 120         struct CtdlMessage *bmsg = NULL;
 121         int give_up = 0;
 122         recptypes *valid;
 123         int successful_bounce = 0;
 124         static int seq = 0;
 125         StrBuf *BounceMB;
 126         long omsgid = (-1);
 127
 128         syslog(LOG_DEBUG, "smtp_do_bounce() called\n");
 129         strcpy(bounceto, "");
 130         boundary = NewStrBufPlain(HKEY("=_Citadel_Multipart_"));
 131
 132         StrBufAppendPrintf(boundary,
 133                            "%s_%04x%04x",
 134                            config.c_fqdn,
 135                            getpid(),
 136                            ++seq);
 137
 138         lines = num_tokens(instr, '\n');
 139
 140         /* See if it's time to give up on delivery of this message */
 141         for (i=0; i<lines; ++i) {
 142                 extract_token(buf, instr, i, '\n', sizeof buf);
 143                 extract_token(key, buf, 0, '|', sizeof key);
 144                 extract_token(addr, buf, 1, '|', sizeof addr);
 145                 if (!strcasecmp(key, "submitted")) {
 146                         submitted = atol(addr);
 147                 }
 148         }
 149
 150         if ( (time(NULL) - submitted) > SMTP_GIVE_UP ) {
 151                 give_up = 1;
 152         }
 153
 154         /* Start building our bounce message */
 155
 156         bmsg = (struct CtdlMessage *) malloc(sizeof(struct CtdlMessage));
 157         if (bmsg == NULL) return;
 158         memset(bmsg, 0, sizeof(struct CtdlMessage));
 159         BounceMB = NewStrBufPlain(NULL, 1024);
 160
 161         bmsg->cm_magic = CTDLMESSAGE_MAGIC;
 162         bmsg->cm_anon_type = MES_NORMAL;
 163         bmsg->cm_format_type = FMT_RFC822;
 164         CM_SetField(bmsg, eAuthor, HKEY("Citadel"));
 165         CM_SetField(bmsg, eOriginalRoom, HKEY(MAILROOM));
 166         CM_SetField(bmsg, eNodeName, CFG_KEY(c_nodename));
 167         CM_SetField(bmsg, eMsgSubject, HKEY("Delivery Status Notification (Failure)"));
 168         StrBufAppendBufPlain(
 169                 BounceMB,
 170                 HKEY("Content-type: multipart/mixed; boundary=\""), 0);
 171         StrBufAppendBuf(BounceMB, boundary, 0);
 172         StrBufAppendBufPlain(BounceMB, HKEY("\"\r\n"), 0);
 173         StrBufAppendBufPlain(BounceMB, HKEY("MIME-Version: 1.0\r\n"), 0);
 174         StrBufAppendBufPlain(BounceMB, HKEY("X-Mailer: " CITADEL "\r\n"), 0);
 175
 176         StrBufAppendBufPlain(
 177                 BounceMB,
 178                 HKEY("\r\nThis is a multipart message in MIME format."
 179                      "\r\n\r\n"), 0);
 180
 181         StrBufAppendBufPlain(BounceMB, HKEY("--"), 0);
 182         StrBufAppendBuf(BounceMB, boundary, 0);
 183         StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 184         StrBufAppendBufPlain(BounceMB,
 185                              HKEY("Content-type: text/plain\r\n\r\n"), 0);
 186
 187         if (give_up)
 188         {
 189                 StrBufAppendBufPlain(
 190                         BounceMB,
 191                         HKEY("A message you sent could not be delivered "
 192                              "to some or all of its recipients\ndue to "
 193                              "prolonged unavailability of its destination(s).\n"
 194                              "Giving up on the following addresses:\n\n"), 0);
 195         }
 196         else
 197         {
 198                 StrBufAppendBufPlain(
 199                         BounceMB,
 200                         HKEY("A message you sent could not be delivered "
 201                              "to some or all of its recipients.\n"
 202                              "The following addresses were undeliverable:\n\n"
 203                                 ), 0);
 204         }
 205
 206         /*
 207          * Now go through the instructions checking for stuff.
 208          */
 209         for (i=0; i<lines; ++i) {
 210                 long addrlen;
 211                 long dsnlen;
 212                 extract_token(buf, instr, i, '\n', sizeof buf);
 213                 extract_token(key, buf, 0, '|', sizeof key);
 214                 addrlen = extract_token(addr, buf, 1, '|', sizeof addr);
 215                 status = extract_int(buf, 2);
 216                 dsnlen = extract_token(dsn, buf, 3, '|', sizeof dsn);
 217                 bounce_this = 0;
 218
 219                 syslog(LOG_DEBUG, "key=<%s> addr=<%s> status=%d dsn=<%s>\n",
 220                        key, addr, status, dsn);
 221
 222                 if (!strcasecmp(key, "bounceto")) {
 223                         strcpy(bounceto, addr);
 224                 }
 225
 226                 if (!strcasecmp(key, "msgid")) {
 227                         omsgid = atol(addr);
 228                 }
 229
 230                 if (!strcasecmp(key, "remote")) {
 231                         if (status == 5) bounce_this = 1;
 232                         if (give_up) bounce_this = 1;
 233                 }
 234
 235                 if (bounce_this) {
 236                         ++num_bounces;
 237
 238                         StrBufAppendBufPlain(BounceMB, addr, addrlen, 0);
 239                         StrBufAppendBufPlain(BounceMB, HKEY(": "), 0);
 240                         StrBufAppendBufPlain(BounceMB, dsn, dsnlen, 0);
 241                         StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 242
 243                         remove_token(instr, i, '\n');
 244                         --i;
 245                         --lines;
 246                 }
 247         }
 248
 249         /* Attach the original message */
 250         if (omsgid >= 0) {
 251                 StrBufAppendBufPlain(BounceMB, HKEY("--"), 0);
 252                 StrBufAppendBuf(BounceMB, boundary, 0);
 253                 StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 254
 255                 StrBufAppendBufPlain(
 256                         BounceMB,
 257                         HKEY("Content-type: message/rfc822\r\n"), 0);
 258
 259                 StrBufAppendBufPlain(
 260                         BounceMB,
 261                         HKEY("Content-Transfer-Encoding: 7bit\r\n"), 0);
 262
 263                 StrBufAppendBufPlain(
 264                         BounceMB,
 265                         HKEY("Content-Disposition: inline\r\n"), 0);
 266
 267                 StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 268
 269                 if (OMsgTxt == NULL) {
 270                         CC->redirect_buffer = NewStrBufPlain(NULL, SIZ);
 271                         CtdlOutputMsg(omsgid,
 272                                       MT_RFC822,
 273                                       HEADERS_ALL,
 274                                       0, 1, NULL, 0,
 275                                       NULL, NULL, NULL);
 276
 277                         StrBufAppendBuf(BounceMB, CC->redirect_buffer, 0);
 278                         FreeStrBuf(&CC->redirect_buffer);
 279                 }
 280                 else {
 281                         StrBufAppendBuf(BounceMB, OMsgTxt, 0);
 282                 }
 283         }
 284
 285         /* Close the multipart MIME scope */
 286         StrBufAppendBufPlain(BounceMB, HKEY("--"), 0);
 287         StrBufAppendBuf(BounceMB, boundary, 0);
 288         StrBufAppendBufPlain(BounceMB, HKEY("--\r\n"), 0);
 289         CM_SetAsFieldSB(bmsg, eMesageText, &BounceMB);
 290
 291         /* Deliver the bounce if there's anything worth mentioning */
 292         syslog(LOG_DEBUG, "num_bounces = %d\n", num_bounces);
 293         if (num_bounces > 0) {
 294
 295                 /* First try the user who sent the message */
 296                 if (IsEmptyStr(bounceto))
 297                         syslog(LOG_ERR, "No bounce address specified\n");
 298                 else
 299                         syslog(LOG_DEBUG, "bounce to user <%s>\n", bounceto);
 300                 /* Can we deliver the bounce to the original sender? */
 301                 valid = validate_recipients(bounceto,
 302                                             smtp_get_Recipients (),
 303                                             0);
 304                 if (valid != NULL) {
 305                         if (valid->num_error == 0) {
 306                                 CtdlSubmitMsg(bmsg, valid, "", QP_EADDR);
 307                                 successful_bounce = 1;
 308                         }
 309                 }
 310
 311                 /* If not, post it in the Aide> room */
 312                 if (successful_bounce == 0) {
 313                         CtdlSubmitMsg(bmsg, NULL, config.c_aideroom, QP_EADDR);
 314                 }
 315
 316                 /* Free up the memory we used */
 317                 if (valid != NULL) {
 318                         free_recipients(valid);
 319                 }
 320         }
 321         FreeStrBuf(&boundary);
 322         CM_Free(bmsg);
 323         syslog(LOG_DEBUG, "Done processing bounces\n");
 324 }