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) 1998-2015 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  * This program is distributed in the hope that it will be useful,
  29  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  30  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  31  * GNU General Public License for more details.
  32  */
  33
  34 #include "sysdep.h"
  35 #include <stdlib.h>
  36 #include <unistd.h>
  37 #include <stdio.h>
  38 #include <termios.h>
  39 #include <fcntl.h>
  40 #include <signal.h>
  41 #include <pwd.h>
  42 #include <errno.h>
  43 #include <sys/types.h>
  44 #include <syslog.h>
  45
  46 #if TIME_WITH_SYS_TIME
  47 # include <sys/time.h>
  48 # include <time.h>
  49 #else
  50 # if HAVE_SYS_TIME_H
  51 #  include <sys/time.h>
  52 # else
  53 #  include <time.h>
  54 # endif
  55 #endif
  56
  57 #include <sys/wait.h>
  58 #include <ctype.h>
  59 #include <string.h>
  60 #include <limits.h>
  61 #include <sys/socket.h>
  62 #include <netinet/in.h>
  63 #include <arpa/inet.h>
  64 #include <libcitadel.h>
  65 #include "citadel.h"
  66 #include "server.h"
  67 #include "citserver.h"
  68 #include "support.h"
  69 #include "config.h"
  70 #include "control.h"
  71 #include "user_ops.h"
  72 #include "database.h"
  73 #include "msgbase.h"
  74 #include "internet_addressing.h"
  75 #include "genstamp.h"
  76 #include "domain.h"
  77 #include "clientsocket.h"
  78 #include "locate_host.h"
  79 #include "citadel_dirs.h"
  80
  81 #include "ctdl_module.h"
  82
  83 #include "smtp_util.h"
  84
  85 const char *smtp_get_Recipients(void)
  86 {
  87         citsmtp *sSMTP = SMTP;
  88
  89         if (sSMTP == NULL)
  90                 return NULL;
  91         else return ChrPtr(sSMTP->from);
  92 }
  93
  94
  95 /*
  96  * smtp_do_bounce() is caled by smtp_do_procmsg() to scan a set of delivery
  97  * instructions for "5" codes (permanent fatal errors) and produce/deliver
  98  * a "bounce" message (delivery status notification).
  99  */
 100 void smtp_do_bounce(char *instr, StrBuf *OMsgTxt)
 101 {
 102         int i;
 103         int lines;
 104         int status;
 105         char buf[1024];
 106         char key[1024];
 107         char addr[1024];
 108         char dsn[1024];
 109         char bounceto[1024];
 110         StrBuf *boundary;
 111         int num_bounces = 0;
 112         int bounce_this = 0;
 113         time_t submitted = 0L;
 114         struct CtdlMessage *bmsg = NULL;
 115         int give_up = 0;
 116         recptypes *valid;
 117         int successful_bounce = 0;
 118         static int seq = 0;
 119         StrBuf *BounceMB;
 120         long omsgid = (-1);
 121
 122         syslog(LOG_DEBUG, "smtp_do_bounce() called\n");
 123         strcpy(bounceto, "");
 124         boundary = NewStrBufPlain(HKEY("=_Citadel_Multipart_"));
 125
 126         StrBufAppendPrintf(boundary, "%s_%04x%04x", CtdlGetConfigStr("c_fqdn"), getpid(), ++seq);
 127
 128         lines = num_tokens(instr, '\n');
 129
 130         /* See if it's time to give up on delivery of this message */
 131         for (i=0; i<lines; ++i) {
 132                 extract_token(buf, instr, i, '\n', sizeof buf);
 133                 extract_token(key, buf, 0, '|', sizeof key);
 134                 extract_token(addr, buf, 1, '|', sizeof addr);
 135                 if (!strcasecmp(key, "submitted")) {
 136                         submitted = atol(addr);
 137                 }
 138         }
 139
 140         if ( (time(NULL) - submitted) > SMTP_GIVE_UP ) {
 141                 give_up = 1;
 142         }
 143
 144         /* Start building our bounce message */
 145
 146         bmsg = (struct CtdlMessage *) malloc(sizeof(struct CtdlMessage));
 147         if (bmsg == NULL) return;
 148         memset(bmsg, 0, sizeof(struct CtdlMessage));
 149         BounceMB = NewStrBufPlain(NULL, 1024);
 150
 151         bmsg->cm_magic = CTDLMESSAGE_MAGIC;
 152         bmsg->cm_anon_type = MES_NORMAL;
 153         bmsg->cm_format_type = FMT_RFC822;
 154         CM_SetField(bmsg, eAuthor, HKEY("Citadel"));
 155         CM_SetField(bmsg, eOriginalRoom, HKEY(MAILROOM));
 156         CM_SetField(bmsg, eNodeName, CtdlGetConfigStr("c_nodename"), strlen(CtdlGetConfigStr("c_nodename")));
 157         CM_SetField(bmsg, eMsgSubject, HKEY("Delivery Status Notification (Failure)"));
 158         StrBufAppendBufPlain(BounceMB, HKEY("Content-type: multipart/mixed; boundary=\""), 0);
 159         StrBufAppendBuf(BounceMB, boundary, 0);
 160         StrBufAppendBufPlain(BounceMB, HKEY("\"\r\n"), 0);
 161         StrBufAppendBufPlain(BounceMB, HKEY("MIME-Version: 1.0\r\n"), 0);
 162         StrBufAppendBufPlain(BounceMB, HKEY("X-Mailer: " CITADEL "\r\n"), 0);
 163
 164         StrBufAppendBufPlain(
 165                 BounceMB,
 166                 HKEY("\r\nThis is a multipart message in MIME format."
 167                      "\r\n\r\n"), 0);
 168
 169         StrBufAppendBufPlain(BounceMB, HKEY("--"), 0);
 170         StrBufAppendBuf(BounceMB, boundary, 0);
 171         StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 172         StrBufAppendBufPlain(BounceMB,
 173                              HKEY("Content-type: text/plain\r\n\r\n"), 0);
 174
 175         if (give_up)
 176         {
 177                 StrBufAppendBufPlain(
 178                         BounceMB,
 179                         HKEY("A message you sent could not be delivered "
 180                              "to some or all of its recipients\ndue to "
 181                              "prolonged unavailability of its destination(s).\n"
 182                              "Giving up on the following addresses:\n\n"), 0);
 183         }
 184         else
 185         {
 186                 StrBufAppendBufPlain(
 187                         BounceMB,
 188                         HKEY("A message you sent could not be delivered "
 189                              "to some or all of its recipients.\n"
 190                              "The following addresses were undeliverable:\n\n"
 191                                 ), 0);
 192         }
 193
 194         /*
 195          * Now go through the instructions checking for stuff.
 196          */
 197         for (i=0; i<lines; ++i) {
 198                 long addrlen;
 199                 long dsnlen;
 200                 extract_token(buf, instr, i, '\n', sizeof buf);
 201                 extract_token(key, buf, 0, '|', sizeof key);
 202                 addrlen = extract_token(addr, buf, 1, '|', sizeof addr);
 203                 status = extract_int(buf, 2);
 204                 dsnlen = extract_token(dsn, buf, 3, '|', sizeof dsn);
 205                 bounce_this = 0;
 206
 207                 syslog(LOG_DEBUG, "key=<%s> addr=<%s> status=%d dsn=<%s>\n",
 208                        key, addr, status, dsn);
 209
 210                 if (!strcasecmp(key, "bounceto")) {
 211                         strcpy(bounceto, addr);
 212                 }
 213
 214                 if (!strcasecmp(key, "msgid")) {
 215                         omsgid = atol(addr);
 216                 }
 217
 218                 if (!strcasecmp(key, "remote")) {
 219                         if (status == 5) bounce_this = 1;
 220                         if (give_up) bounce_this = 1;
 221                 }
 222
 223                 if (bounce_this) {
 224                         ++num_bounces;
 225
 226                         StrBufAppendBufPlain(BounceMB, addr, addrlen, 0);
 227                         StrBufAppendBufPlain(BounceMB, HKEY(": "), 0);
 228                         StrBufAppendBufPlain(BounceMB, dsn, dsnlen, 0);
 229                         StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 230
 231                         remove_token(instr, i, '\n');
 232                         --i;
 233                         --lines;
 234                 }
 235         }
 236
 237         /* Attach the original message */
 238         if (omsgid >= 0) {
 239                 StrBufAppendBufPlain(BounceMB, HKEY("--"), 0);
 240                 StrBufAppendBuf(BounceMB, boundary, 0);
 241                 StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 242
 243                 StrBufAppendBufPlain(
 244                         BounceMB,
 245                         HKEY("Content-type: message/rfc822\r\n"), 0);
 246
 247                 StrBufAppendBufPlain(
 248                         BounceMB,
 249                         HKEY("Content-Transfer-Encoding: 7bit\r\n"), 0);
 250
 251                 StrBufAppendBufPlain(
 252                         BounceMB,
 253                         HKEY("Content-Disposition: inline\r\n"), 0);
 254
 255                 StrBufAppendBufPlain(BounceMB, HKEY("\r\n"), 0);
 256
 257                 if (OMsgTxt == NULL) {
 258                         CC->redirect_buffer = NewStrBufPlain(NULL, SIZ);
 259                         CtdlOutputMsg(omsgid,
 260                                       MT_RFC822,
 261                                       HEADERS_ALL,
 262                                       0, 1, NULL, 0,
 263                                       NULL, NULL, NULL);
 264
 265                         StrBufAppendBuf(BounceMB, CC->redirect_buffer, 0);
 266                         FreeStrBuf(&CC->redirect_buffer);
 267                 }
 268                 else {
 269                         StrBufAppendBuf(BounceMB, OMsgTxt, 0);
 270                 }
 271         }
 272
 273         /* Close the multipart MIME scope */
 274         StrBufAppendBufPlain(BounceMB, HKEY("--"), 0);
 275         StrBufAppendBuf(BounceMB, boundary, 0);
 276         StrBufAppendBufPlain(BounceMB, HKEY("--\r\n"), 0);
 277         CM_SetAsFieldSB(bmsg, eMesageText, &BounceMB);
 278
 279         /* Deliver the bounce if there's anything worth mentioning */
 280         syslog(LOG_DEBUG, "num_bounces = %d\n", num_bounces);
 281         if (num_bounces > 0) {
 282
 283                 /* First try the user who sent the message */
 284                 if (IsEmptyStr(bounceto))
 285                         syslog(LOG_ERR, "No bounce address specified\n");
 286                 else
 287                         syslog(LOG_DEBUG, "bounce to user <%s>\n", bounceto);
 288                 /* Can we deliver the bounce to the original sender? */
 289                 valid = validate_recipients(bounceto,
 290                                             smtp_get_Recipients (),
 291                                             0);
 292                 if (valid != NULL) {
 293                         if (valid->num_error == 0) {
 294                                 CtdlSubmitMsg(bmsg, valid, "", QP_EADDR);
 295                                 successful_bounce = 1;
 296                         }
 297                 }
 298
 299                 /* If not, post it in the Aide> room */
 300                 if (successful_bounce == 0) {
 301                         CtdlSubmitMsg(bmsg, NULL, CtdlGetConfigStr("c_aideroom"), QP_EADDR);
 302                 }
 303
 304                 /* Free up the memory we used */
 305                 if (valid != NULL) {
 306                         free_recipients(valid);
 307                 }
 308         }
 309         FreeStrBuf(&boundary);
 310         CM_Free(bmsg);
 311         syslog(LOG_DEBUG, "Done processing bounces\n");
 312 }