citadel/modules/listsub/serv_listsub.c

   1 // This module handles self-service subscription/unsubscription to mail lists.
   2 //
   3 // Copyright (c) 2002-2022 by the citadel.org team
   4 //
   5 // This program is open source software.  It runs great on the
   6 // Linux operating system (and probably elsewhere).  You can use,
   7 // copy, and run it under the terms of the GNU General Public
   8 // License version 3.
   9 //
  10 // This program is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14
  15 #include "sysdep.h"
  16 #include <stdlib.h>
  17 #include <unistd.h>
  18 #include <stdio.h>
  19 #include <fcntl.h>
  20 #include <ctype.h>
  21 #include <signal.h>
  22 #include <pwd.h>
  23 #include <errno.h>
  24 #include <sys/types.h>
  25 #include <dirent.h>
  26 #include <time.h>
  27 #include <sys/wait.h>
  28 #include <string.h>
  29 #include <limits.h>
  30 #include <crypt.h>
  31 #include <libcitadel.h>
  32 #include "citadel.h"
  33 #include "server.h"
  34 #include "citserver.h"
  35 #include "support.h"
  36 #include "config.h"
  37 #include "user_ops.h"
  38 #include "database.h"
  39 #include "msgbase.h"
  40 #include "internet_addressing.h"
  41 #include "clientsocket.h"
  42 #include "ctdl_module.h"
  43
  44
  45 enum {                          // one of these gets passed to do_subscribe_or_unsubscribe() so it knows what we asked for
  46         UNSUBSCRIBE,
  47         SUBSCRIBE
  48 };
  49
  50
  51 // The confirmation token will be generated by combining the room name and email address with the host key,
  52 // and then generating an encrypted hash of that string.  The encrypted hash is included as part of the
  53 // confirmation link.
  54 void generate_confirmation_token(char *token_buf, size_t token_buf_len, char *roomname, char *emailaddr) {
  55         char string_to_hash[1024];
  56         struct crypt_data cd;
  57         char *ptr;
  58
  59         snprintf(string_to_hash, sizeof string_to_hash, "%s|%s|%s", roomname, emailaddr, CtdlGetConfigStr("host_key"));
  60         memset(&cd, 0, sizeof cd);
  61
  62         strncpy(token_buf, crypt_r(string_to_hash, "$1$ctdl", &cd), token_buf_len);
  63
  64         for (ptr=token_buf; *ptr; ++ptr) {
  65                 if (!isalnum((char)*ptr)) *ptr='X';
  66         }
  67 }
  68
  69
  70 // This generates an email with a link the user clicks to confirm a list subscription.
  71 void send_subscribe_confirmation_email(char *roomname, char *emailaddr, char *url, char *confirmation_token) {
  72         // We need a URL-safe representation of the room name
  73         char urlroom[ROOMNAMELEN+10];
  74         urlesc(urlroom, sizeof(urlroom), roomname);
  75
  76         char from_address[1024];
  77         snprintf(from_address, sizeof from_address, "noreply@%s", CtdlGetConfigStr("c_fqdn"));
  78
  79         char emailtext[SIZ];
  80         snprintf(emailtext, sizeof emailtext,
  81                 "MIME-Version: 1.0\n"
  82                 "Content-Type: multipart/alternative; boundary=\"__ctdlmultipart__\"\n"
  83                 "\n"
  84                 "This is a multipart message in MIME format.\n"
  85                 "\n"
  86                 "--__ctdlmultipart__\n"
  87                 "Content-type: text/plain\n"
  88                 "\n"
  89                 "Someone (probably you) has submitted a request to subscribe\n"
  90                 "<%s> to the <%s> mailing list.\n"
  91                 "\n"
  92                 "Please go here to confirm this request:\n"
  93                 "%s?cmd=confirm_subscribe&email=%s&room=%s&token=%s\n"
  94                 "\n"
  95                 "If this request has been submitted in error and you do not\n"
  96                 "wish to receive the <%s> mailing list, simply do nothing,\n"
  97                 "and you will not receive any further mailings.\n"
  98                 "\n"
  99                 "--__ctdlmultipart__\n"
 100                 "Content-type: text/html\n"
 101                 "\n"
 102                 "<html><body><p>Someone (probably you) has submitted a request to subscribe "
 103                 "<strong>%s</strong> to the <strong>%s</strong> mailing list.</p>"
 104                 "<p>Please go here to confirm this request:</p>"
 105                 "<p><a href=\"%s?cmd=confirm_subscribe&email=%s&room=%s&token=%s\">"
 106                 "%s?cmd=confirm_subscribe&email=%s&room=%s&token=%s</a></p>"
 107                 "<p>If this request has been submitted in error and you do not "
 108                 "wish to receive the <strong>%s<strong> mailing list, simply do nothing, "
 109                 "and you will not receive any further mailings.</p>"
 110                 "</body></html>\n"
 111                 "\n"
 112                 "--__ctdlmultipart__--\n"
 113                 ,
 114                 emailaddr, roomname,
 115                 url, emailaddr, urlroom, confirmation_token,
 116                 roomname
 117                 ,
 118                 emailaddr, roomname,
 119                 url, emailaddr, urlroom, confirmation_token,
 120                 url, emailaddr, urlroom, confirmation_token,
 121                 roomname
 122         );
 123
 124         quickie_message("Citadel", from_address, emailaddr, NULL, emailtext, FMT_RFC822, "Please confirm your list subscription");
 125         cprintf("%d confirmation email sent\n", CIT_OK);
 126 }
 127
 128
 129 // This generates an email with a link the user clicks to confirm a list unsubscription.
 130 void send_unsubscribe_confirmation_email(char *roomname, char *emailaddr, char *url, char *confirmation_token) {
 131         // We need a URL-safe representation of the room name
 132         char urlroom[ROOMNAMELEN+10];
 133         urlesc(urlroom, sizeof(urlroom), roomname);
 134
 135         char from_address[1024];
 136         snprintf(from_address, sizeof from_address, "noreply@%s", CtdlGetConfigStr("c_fqdn"));
 137
 138         char emailtext[SIZ];
 139         snprintf(emailtext, sizeof emailtext,
 140                 "MIME-Version: 1.0\n"
 141                 "Content-Type: multipart/alternative; boundary=\"__ctdlmultipart__\"\n"
 142                 "\n"
 143                 "This is a multipart message in MIME format.\n"
 144                 "\n"
 145                 "--__ctdlmultipart__\n"
 146                 "Content-type: text/plain\n"
 147                 "\n"
 148                 "Someone (probably you) has submitted a request to unsubscribe\n"
 149                 "<%s> from the <%s> mailing list.\n"
 150                 "\n"
 151                 "Please go here to confirm this request:\n"
 152                 "%s?cmd=confirm_unsubscribe&email=%s&room=%s&token=%s\n"
 153                 "\n"
 154                 "If this request has been submitted in error and you still\n"
 155                 "wish to receive the <%s> mailing list, simply do nothing,\n"
 156                 "and you will remain subscribed.\n"
 157                 "\n"
 158                 "--__ctdlmultipart__\n"
 159                 "Content-type: text/html\n"
 160                 "\n"
 161                 "<html><body><p>Someone (probably you) has submitted a request to unsubscribe "
 162                 "<strong>%s</strong> from the <strong>%s</strong> mailing list.</p>"
 163                 "<p>Please go here to confirm this request:</p>"
 164                 "<p><a href=\"%s?cmd=confirm_unsubscribe&email=%s&room=%s&token=%s\">"
 165                 "%s?cmd=confirm_unsubscribe&email=%s&room=%s&token=%s</a></p>"
 166                 "<p>If this request has been submitted in error and you still "
 167                 "wish to receive the <strong>%s<strong> mailing list, simply do nothing, "
 168                 "and you will remain subscribed.</p>"
 169                 "</body></html>\n"
 170                 "\n"
 171                 "--__ctdlmultipart__--\n"
 172                 ,
 173                 emailaddr, roomname,
 174                 url, emailaddr, urlroom, confirmation_token,
 175                 roomname
 176                 ,
 177                 emailaddr, roomname,
 178                 url, emailaddr, urlroom, confirmation_token,
 179                 url, emailaddr, urlroom, confirmation_token,
 180                 roomname
 181         );
 182
 183         quickie_message("Citadel", from_address, emailaddr, NULL, emailtext, FMT_RFC822, "Please confirm your list unsubscription");
 184         cprintf("%d confirmation email sent\n", CIT_OK);
 185 }
 186
 187
 188 // Confirm a list subscription or unsubscription
 189 void do_confirm(int cmd, char *roomname, char *emailaddr, char *url, char *generated_token, char *supplied_token) {
 190         int i;
 191         char buf[1024];
 192         int config_lines = 0;
 193         char *oldnetconfig, *newnetconfig;
 194
 195         // During opt #1, the server generated a persistent confirmation token for the user+room combination.
 196         // Let's see if the user has supplied the same token during opt #2.
 197         if (strcmp(generated_token, supplied_token)) {
 198                 cprintf("%d This request could not be authenticated.\n", ERROR + PASSWORD_REQUIRED);
 199                 return;
 200         }
 201
 202         // If the generated token matches the supplied token, the request is authentic.  Do what it says.
 203
 204         // Load the room's network configuration...
 205         oldnetconfig = LoadRoomNetConfigFile(CC->room.QRnumber);
 206         if (!oldnetconfig) {
 207                 oldnetconfig = strdup("");
 208         }
 209
 210         // The new netconfig begins with an empty buffer...
 211         begin_critical_section(S_NETCONFIGS);
 212         newnetconfig = malloc(strlen(oldnetconfig) + 1024);
 213         newnetconfig[0] = 0;
 214
 215         // Load the config lines in one by one, skipping any that reference this subscriber.  Also remove blank lines.
 216         config_lines = num_tokens(oldnetconfig, '\n');
 217         for (i=0; i<config_lines; ++i) {
 218                 char buf_email[256];
 219                 extract_token(buf, oldnetconfig, i, '\n', sizeof buf);
 220                 extract_token(buf_email, buf, 1, '|', sizeof buf_email);
 221                 if ( !IsEmptyStr(buf) && (strcasecmp(buf_email, emailaddr)) ) {
 222                         sprintf(&newnetconfig[strlen(newnetconfig)], "%s\n", buf);
 223                 }
 224         }
 225
 226         // We have now removed all lines containing the subscriber's email address.  This deletes any pending requests.
 227         // If this was an unsubscribe operation, they're now gone from the list.
 228         // But if this was a subscribe operation, we now need to add them.
 229         if (cmd == SUBSCRIBE) {
 230                 sprintf(&newnetconfig[strlen(newnetconfig)], "listrecp|%s\n", emailaddr);
 231         }
 232
 233         // write it back to disk
 234         SaveRoomNetConfigFile(CC->room.QRnumber, newnetconfig);
 235         end_critical_section(S_NETCONFIGS);
 236         free(oldnetconfig);
 237         free(newnetconfig);
 238         cprintf("%d The pending request was confirmed.\n", CIT_OK);
 239 }
 240
 241
 242 // process subscribe/unsubscribe requests and confirmations
 243 void cmd_lsub(char *cmdbuf) {
 244         char cmd[20];
 245         char roomname[ROOMNAMELEN];
 246         char emailaddr[1024];
 247         char url[1024];
 248         char generated_token[128];
 249         char supplied_token[128];
 250
 251         extract_token(cmd, cmdbuf, 0, '|', sizeof cmd);                         // token 0 is the sub-command being sent
 252         extract_token(roomname, cmdbuf, 1, '|', sizeof roomname);               // token 1 is always a room name
 253         extract_token(emailaddr, cmdbuf, 2, '|', sizeof emailaddr);             // token 2 is the subscriber's email address
 254         extract_token(url, cmdbuf, 3, '|', sizeof url);                         // token 3 is the URL at which we subscribed
 255         extract_token(supplied_token, cmdbuf, 4, '|', sizeof supplied_token);   // token 4 is the token supplied by the caller
 256
 257         // First confirm that the caller is referencing a room that actually exists.
 258         if (CtdlGetRoom(&CC->room, roomname) != 0) {
 259                 cprintf("%d There is no list called '%s'\n", ERROR + ROOM_NOT_FOUND, roomname);
 260                 return;
 261         }
 262
 263         if ((CC->room.QRflags2 & QR2_SELFLIST) == 0) {
 264                 cprintf("%d '%s' does not accept subscribe/unsubscribe requests.\n", ERROR + ROOM_NOT_FOUND, roomname);
 265                 return;
 266         }
 267
 268         // Generate a confirmation token -- either to supply to the user for opt #1 or to compare for opt #2
 269         generate_confirmation_token(generated_token, sizeof generated_token, roomname, emailaddr);
 270
 271         // Now parse the command.
 272         if (!strcasecmp(cmd, "subscribe")) {
 273                 send_subscribe_confirmation_email(roomname, emailaddr, url, generated_token);
 274         }
 275
 276         else if (!strcasecmp(cmd, "unsubscribe")) {
 277                 send_unsubscribe_confirmation_email(roomname, emailaddr, url, generated_token);
 278         }
 279
 280         else if (!strcasecmp(cmd, "confirm_subscribe")) {
 281                 do_confirm(SUBSCRIBE, roomname, emailaddr, url, generated_token, supplied_token);
 282         }
 283
 284         else if (!strcasecmp(cmd, "confirm_unsubscribe")) {
 285                 do_confirm(UNSUBSCRIBE, roomname, emailaddr, url, generated_token, supplied_token);
 286         }
 287
 288         else {                                                                  // sorry man, I can't deal with that
 289                 cprintf("%d Invalid command '%s'\n", ERROR + ILLEGAL_VALUE, cmd);
 290         }
 291 }
 292
 293
 294 /*
 295  * Module entry point
 296  */
 297 CTDL_MODULE_INIT(listsub)
 298 {
 299         if (!threading)
 300         {
 301                 CtdlRegisterProtoHook(cmd_lsub, "LSUB", "List subscribe/unsubscribe");
 302         }
 303
 304         /* return our module name for the log */
 305         return "listsub";
 306 }