plugins/check_smtp.c

   1 /******************************************************************************
   2
   3  This program is free software; you can redistribute it and/or modify
   4  it under the terms of the GNU General Public License as published by
   5  the Free Software Foundation; either version 2 of the License, or
   6  (at your option) any later version.
   7
   8  This program is distributed in the hope that it will be useful,
   9  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  GNU General Public License for more details.
  12
  13  You should have received a copy of the GNU General Public License
  14  along with this program; if not, write to the Free Software
  15  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  16
  17  $Id$
  18
  19 ******************************************************************************/
  20
  21 const char *progname = "check_smtp";
  22 const char *revision = "$Revision$";
  23 const char *copyright = "2000-2004";
  24 const char *email = "nagiosplug-devel@lists.sourceforge.net";
  25
  26 #include "common.h"
  27 #include "netutils.h"
  28 #include "utils.h"
  29
  30 #ifdef HAVE_SSL
  31 int check_cert = FALSE;
  32 int days_till_exp;
  33 #  define my_recv(buf, len) ((use_ssl && ssl_established) ? np_net_ssl_read(buf, len) : read(sd, buf, len))
  34 #  define my_send(buf, len) ((use_ssl && ssl_established) ? np_net_ssl_write(buf, len) : send(sd, buf, len, 0))
  35 #else /* ifndef HAVE_SSL */
  36 #  define my_recv(buf, len) read(sd, buf, len)
  37 #  define my_send(buf, len) send(sd, buf, len, 0)
  38 #endif
  39
  40 enum {
  41         SMTP_PORT       = 25
  42 };
  43 #define SMTP_EXPECT "220"
  44 #define SMTP_HELO "HELO "
  45 #define SMTP_EHLO "EHLO "
  46 #define SMTP_QUIT "QUIT\r\n"
  47 #define SMTP_STARTTLS "STARTTLS\r\n"
  48
  49 #ifndef HOST_MAX_BYTES
  50 #define HOST_MAX_BYTES 255
  51 #endif
  52
  53 #define EHLO_SUPPORTS_STARTTLS 1
  54
  55 int process_arguments (int, char **);
  56 int validate_arguments (void);
  57 void print_help (void);
  58 void print_usage (void);
  59 int my_close(void);
  60
  61 #ifdef HAVE_REGEX_H
  62 #include <regex.h>
  63 char regex_expect[MAX_INPUT_BUFFER] = "";
  64 regex_t preg;
  65 regmatch_t pmatch[10];
  66 char timestamp[20] = "";
  67 char errbuf[MAX_INPUT_BUFFER];
  68 int cflags = REG_EXTENDED | REG_NOSUB | REG_NEWLINE;
  69 int eflags = 0;
  70 int errcode, excode;
  71 #endif
  72
  73 int server_port = SMTP_PORT;
  74 char *server_address = NULL;
  75 char *server_expect = NULL;
  76 int smtp_use_dummycmd = 0;
  77 char *mail_command = NULL;
  78 char *from_arg = NULL;
  79 int ncommands=0;
  80 int command_size=0;
  81 int nresponses=0;
  82 int response_size=0;
  83 char **commands = NULL;
  84 char **responses = NULL;
  85 int warning_time = 0;
  86 int check_warning_time = FALSE;
  87 int critical_time = 0;
  88 int check_critical_time = FALSE;
  89 int verbose = 0;
  90 int use_ssl = FALSE;
  91 short use_ehlo = FALSE;
  92 short ssl_established = 0;
  93 char *localhostname = NULL;
  94 int sd;
  95 char buffer[MAX_INPUT_BUFFER];
  96 enum {
  97   TCP_PROTOCOL = 1,
  98   UDP_PROTOCOL = 2,
  99   MAXBUF = 1024
 100 };
 101
 102 int
 103 main (int argc, char **argv)
 104 {
 105         short supports_tls=FALSE;
 106         int n = 0;
 107         double elapsed_time;
 108         long microsec;
 109         int result = STATE_UNKNOWN;
 110         char *cmd_str = NULL;
 111         char *helocmd = NULL;
 112         struct timeval tv;
 113         struct hostent *hp;
 114
 115         setlocale (LC_ALL, "");
 116         bindtextdomain (PACKAGE, LOCALEDIR);
 117         textdomain (PACKAGE);
 118
 119         if (process_arguments (argc, argv) == ERROR)
 120                 usage4 (_("Could not parse arguments"));
 121
 122         /* initialize the HELO command with the localhostname */
 123         if(! localhostname){
 124                 localhostname = malloc (HOST_MAX_BYTES);
 125                 if(!localhostname){
 126                         printf(_("malloc() failed!\n"));
 127                         return STATE_CRITICAL;
 128                 }
 129                 if(gethostname(localhostname, HOST_MAX_BYTES)){
 130                         printf(_("gethostname() failed!\n"));
 131                         return STATE_CRITICAL;
 132                 }
 133                 hp = gethostbyname(localhostname);
 134                 if(!hp) helocmd = localhostname;
 135                 else helocmd = hp->h_name;
 136         } else {
 137                 helocmd = localhostname;
 138         }
 139         if(use_ehlo)
 140                 asprintf (&helocmd, "%s%s%s", SMTP_EHLO, helocmd, "\r\n");
 141         else
 142                 asprintf (&helocmd, "%s%s%s", SMTP_HELO, helocmd, "\r\n");
 143
 144         /* initialize the MAIL command with optional FROM command  */
 145         asprintf (&cmd_str, "%sFROM: %s%s", mail_command, from_arg, "\r\n");
 146
 147         if (verbose && smtp_use_dummycmd)
 148                 printf ("FROM CMD: %s", cmd_str);
 149
 150         /* initialize alarm signal handling */
 151         (void) signal (SIGALRM, socket_timeout_alarm_handler);
 152
 153         /* set socket timeout */
 154         (void) alarm (socket_timeout);
 155
 156         /* start timer */
 157         gettimeofday (&tv, NULL);
 158
 159         /* try to connect to the host at the given port number */
 160         result = my_tcp_connect (server_address, server_port, &sd);
 161
 162         if (result == STATE_OK) { /* we connected */
 163
 164                 /* watch for the SMTP connection string and */
 165                 /* return a WARNING status if we couldn't read any data */
 166                 if (recv (sd, buffer, MAX_INPUT_BUFFER - 1, 0) == -1) {
 167                         printf (_("recv() failed\n"));
 168                         result = STATE_WARNING;
 169                 }
 170                 else {
 171                         if (verbose)
 172                                 printf ("%s", buffer);
 173                         /* strip the buffer of carriage returns */
 174                         strip (buffer);
 175                         /* make sure we find the response we are looking for */
 176                         if (!strstr (buffer, server_expect)) {
 177                                 if (server_port == SMTP_PORT)
 178                                         printf (_("Invalid SMTP response received from host\n"));
 179                                 else
 180                                         printf (_("Invalid SMTP response received from host on port %d\n"),
 181                                                                         server_port);
 182                                 result = STATE_WARNING;
 183                         }
 184                 }
 185
 186                 /* send the HELO/EHLO command */
 187                 send(sd, helocmd, strlen(helocmd), 0);
 188
 189                 /* allow for response to helo command to reach us */
 190                 if(read (sd, buffer, MAXBUF - 1) < 0){
 191                         printf (_("recv() failed\n"));
 192                         return STATE_WARNING;
 193                 } else if(use_ehlo){
 194                         buffer[MAXBUF-1]='\0';
 195                         if(strstr(buffer, "250 STARTTLS") != NULL ||
 196                            strstr(buffer, "250-STARTTLS") != NULL){
 197                                 supports_tls=TRUE;
 198                         }
 199                 }
 200
 201                 if(use_ssl && ! supports_tls){
 202                         printf(_("WARNING - TLS not supported by server\n"));
 203                         send (sd, SMTP_QUIT, strlen (SMTP_QUIT), 0);
 204                         return STATE_WARNING;
 205                 }
 206
 207 #ifdef HAVE_SSL
 208                 if(use_ssl) {
 209                   /* send the STARTTLS command */
 210                   send(sd, SMTP_STARTTLS, strlen(SMTP_STARTTLS), 0);
 211
 212                   recv(sd,buffer, MAX_INPUT_BUFFER-1, 0); /* wait for it */
 213                   if (!strstr (buffer, server_expect)) {
 214                     printf (_("Server does not support STARTTLS\n"));
 215                     send (sd, SMTP_QUIT, strlen (SMTP_QUIT), 0);
 216                     return STATE_UNKNOWN;
 217                   }
 218                   result = np_net_ssl_init(sd);
 219                   if(result != STATE_OK) {
 220                     printf (_("CRITICAL - Cannot create SSL context.\n"));
 221                     np_net_ssl_cleanup();
 222                     close(sd);
 223                     return STATE_CRITICAL;
 224                   } else {
 225                         ssl_established = 1;
 226                   }
 227 #  ifdef USE_OPENSSL
 228                   if ( check_cert ) {
 229                     result = np_net_ssl_check_cert(days_till_exp);
 230                     if(result != STATE_OK){
 231                       printf (_("CRITICAL - Cannot retrieve server certificate.\n"));
 232                     }
 233                     my_close();
 234                     return result;
 235                   }
 236 #  endif /* USE_OPENSSL */
 237                 }
 238 #endif
 239
 240                 /* sendmail will syslog a "NOQUEUE" error if session does not attempt
 241                  * to do something useful. This can be prevented by giving a command
 242                  * even if syntax is illegal (MAIL requires a FROM:<...> argument)
 243                  *
 244                  * According to rfc821 you can include a null reversepath in the from command
 245                  * - but a log message is generated on the smtp server.
 246                  *
 247                  * You can disable sending mail_command with '--nocommand'
 248                  * Use the -f option to provide a FROM address
 249                  */
 250                 if (smtp_use_dummycmd) {
 251                   my_send(cmd_str, strlen(cmd_str));
 252                   my_recv(buffer, MAX_INPUT_BUFFER-1);
 253                   if (verbose)
 254                     printf("%s", buffer);
 255                 }
 256
 257                 while (n < ncommands) {
 258                         asprintf (&cmd_str, "%s%s", commands[n], "\r\n");
 259                         my_send(cmd_str, strlen(cmd_str));
 260                         my_recv(buffer, MAX_INPUT_BUFFER-1);
 261                         if (verbose)
 262                                 printf("%s", buffer);
 263                         strip (buffer);
 264                         if (n < nresponses) {
 265 #ifdef HAVE_REGEX_H
 266                                 cflags |= REG_EXTENDED | REG_NOSUB | REG_NEWLINE;
 267                                 errcode = regcomp (&preg, responses[n], cflags);
 268                                 if (errcode != 0) {
 269                                         regerror (errcode, &preg, errbuf, MAX_INPUT_BUFFER);
 270                                         printf (_("Could Not Compile Regular Expression"));
 271                                         return ERROR;
 272                                 }
 273                                 excode = regexec (&preg, buffer, 10, pmatch, eflags);
 274                                 if (excode == 0) {
 275                                         result = STATE_OK;
 276                                 }
 277                                 else if (excode == REG_NOMATCH) {
 278                                         result = STATE_WARNING;
 279                                         printf (_("SMTP %s - Invalid response '%s' to command '%s'\n"), state_text (result), buffer, commands[n]);
 280                                 }
 281                                 else {
 282                                         regerror (excode, &preg, errbuf, MAX_INPUT_BUFFER);
 283                                         printf (_("Execute Error: %s\n"), errbuf);
 284                                         result = STATE_UNKNOWN;
 285                                 }
 286 #else
 287                                 if (strstr(buffer, responses[n])!=buffer) {
 288                                         result = STATE_WARNING;
 289                                         printf (_("SMTP %s - Invalid response '%s' to command '%s'\n"), state_text (result), buffer, commands[n]);
 290                                 }
 291 #endif
 292                         }
 293                         n++;
 294                 }
 295
 296                 /* tell the server we're done */
 297                 my_send (SMTP_QUIT, strlen (SMTP_QUIT));
 298
 299                 /* finally close the connection */
 300                 close (sd);
 301         }
 302
 303         /* reset the alarm */
 304         alarm (0);
 305
 306         microsec = deltime (tv);
 307         elapsed_time = (double)microsec / 1.0e6;
 308
 309         if (result == STATE_OK) {
 310                 if (check_critical_time && elapsed_time > (double) critical_time)
 311                         result = STATE_CRITICAL;
 312                 else if (check_warning_time && elapsed_time > (double) warning_time)
 313                         result = STATE_WARNING;
 314         }
 315
 316         printf (_("SMTP %s - %.3f sec. response time%s%s|%s\n"),
 317                 state_text (result), elapsed_time,
 318           verbose?", ":"", verbose?buffer:"",
 319                 fperfdata ("time", elapsed_time, "s",
 320                           (int)check_warning_time, warning_time,
 321                           (int)check_critical_time, critical_time,
 322                           TRUE, 0, FALSE, 0));
 323
 324         return result;
 325 }
 326
 327
 328
 329 /* process command-line arguments */
 330 int
 331 process_arguments (int argc, char **argv)
 332 {
 333         int c;
 334
 335         int option = 0;
 336         static struct option longopts[] = {
 337                 {"hostname", required_argument, 0, 'H'},
 338                 {"expect", required_argument, 0, 'e'},
 339                 {"critical", required_argument, 0, 'c'},
 340                 {"warning", required_argument, 0, 'w'},
 341                 {"timeout", required_argument, 0, 't'},
 342                 {"port", required_argument, 0, 'p'},
 343                 {"from", required_argument, 0, 'f'},
 344                 {"fqdn", required_argument, 0, 'F'},
 345                 {"command", required_argument, 0, 'C'},
 346                 {"response", required_argument, 0, 'R'},
 347                 {"nocommand", required_argument, 0, 'n'},
 348                 {"verbose", no_argument, 0, 'v'},
 349                 {"version", no_argument, 0, 'V'},
 350                 {"use-ipv4", no_argument, 0, '4'},
 351                 {"use-ipv6", no_argument, 0, '6'},
 352                 {"help", no_argument, 0, 'h'},
 353                 {"starttls",no_argument,0,'S'},
 354                 {"certificate",required_argument,0,'D'},
 355                 {0, 0, 0, 0}
 356         };
 357
 358         if (argc < 2)
 359                 return ERROR;
 360
 361         for (c = 1; c < argc; c++) {
 362                 if (strcmp ("-to", argv[c]) == 0)
 363                         strcpy (argv[c], "-t");
 364                 else if (strcmp ("-wt", argv[c]) == 0)
 365                         strcpy (argv[c], "-w");
 366                 else if (strcmp ("-ct", argv[c]) == 0)
 367                         strcpy (argv[c], "-c");
 368         }
 369
 370         while (1) {
 371                 c = getopt_long (argc, argv, "+hVv46t:p:f:e:c:w:H:C:R:SD:F:",
 372                                  longopts, &option);
 373
 374                 if (c == -1 || c == EOF)
 375                         break;
 376
 377                 switch (c) {
 378                 case 'H':                                                                       /* hostname */
 379                         if (is_host (optarg)) {
 380                                 server_address = optarg;
 381                         }
 382                         else {
 383                                 usage2 (_("Invalid hostname/address"), optarg);
 384                         }
 385                         break;
 386                 case 'p':                                                                       /* port */
 387                         if (is_intpos (optarg))
 388                                 server_port = atoi (optarg);
 389                         else
 390                                 usage4 (_("Port must be a positive integer"));
 391                         break;
 392                 case 'F':
 393                 /* localhostname */
 394                         localhostname = strdup(optarg);
 395                         break;
 396                 case 'f':                                                                       /* from argument */
 397                         from_arg = optarg;
 398                         smtp_use_dummycmd = 1;
 399                         break;
 400                 case 'e':                                                                       /* server expect string on 220  */
 401                         server_expect = optarg;
 402                         break;
 403                 case 'C':                                                                       /* commands  */
 404                         if (ncommands >= command_size) {
 405                                 commands = realloc (commands, command_size+8);
 406                                 if (commands == NULL)
 407                                         die (STATE_UNKNOWN,
 408                                              _("Could not realloc() units [%d]\n"), ncommands);
 409                         }
 410                         commands[ncommands] = optarg;
 411                         ncommands++;
 412                         break;
 413                 case 'R':                                                                       /* server responses */
 414                         if (nresponses >= response_size) {
 415                                 responses = realloc (responses, response_size+8);
 416                                 if (responses == NULL)
 417                                         die (STATE_UNKNOWN,
 418                                              _("Could not realloc() units [%d]\n"), nresponses);
 419                         }
 420                         responses[nresponses] = optarg;
 421                         nresponses++;
 422                         break;
 423                 case 'c':                                                                       /* critical time threshold */
 424                         if (is_intnonneg (optarg)) {
 425                                 critical_time = atoi (optarg);
 426                                 check_critical_time = TRUE;
 427                         }
 428                         else {
 429                                 usage4 (_("Critical time must be a positive integer"));
 430                         }
 431                         break;
 432                 case 'w':                                                                       /* warning time threshold */
 433                         if (is_intnonneg (optarg)) {
 434                                 warning_time = atoi (optarg);
 435                                 check_warning_time = TRUE;
 436                         }
 437                         else {
 438                                 usage4 (_("Warning time must be a positive integer"));
 439                         }
 440                         break;
 441                 case 'v':                                                                       /* verbose */
 442                         verbose++;
 443                         break;
 444                 case 't':                                                                       /* timeout */
 445                         if (is_intnonneg (optarg)) {
 446                                 socket_timeout = atoi (optarg);
 447                         }
 448                         else {
 449                                 usage4 (_("Timeout interval must be a positive integer"));
 450                         }
 451                         break;
 452                 case 'S':
 453                 /* starttls */
 454                         use_ssl = TRUE;
 455                         use_ehlo = TRUE;
 456                         break;
 457                 case 'D':
 458                 /* Check SSL cert validity */
 459 #ifdef USE_OPENSSL
 460                         if (!is_intnonneg (optarg))
 461                                 usage2 ("Invalid certificate expiration period",optarg);
 462                                 days_till_exp = atoi (optarg);
 463                                 check_cert = TRUE;
 464 #else
 465                                 usage (_("SSL support not available - install OpenSSL and recompile"));
 466 #endif
 467                         break;
 468                 case '4':
 469                         address_family = AF_INET;
 470                         break;
 471                 case '6':
 472 #ifdef USE_IPV6
 473                         address_family = AF_INET6;
 474 #else
 475                         usage4 (_("IPv6 support not available"));
 476 #endif
 477                         break;
 478                 case 'V':                                                                       /* version */
 479                         print_revision (progname, revision);
 480                         exit (STATE_OK);
 481                 case 'h':                                                                       /* help */
 482                         print_help ();
 483                         exit (STATE_OK);
 484                 case '?':                                                                       /* help */
 485                         usage2 (_("Unknown argument"), optarg);
 486                 }
 487         }
 488
 489         c = optind;
 490         if (server_address == NULL) {
 491                 if (argv[c]) {
 492                         if (is_host (argv[c]))
 493                                 server_address = argv[c];
 494                         else
 495                                 usage2 (_("Invalid hostname/address"), argv[c]);
 496                 }
 497                 else {
 498                         asprintf (&server_address, "127.0.0.1");
 499                 }
 500         }
 501
 502         if (server_expect == NULL)
 503                 server_expect = strdup (SMTP_EXPECT);
 504
 505         if (mail_command == NULL)
 506                 mail_command = strdup("MAIL ");
 507
 508         if (from_arg==NULL)
 509                 from_arg = strdup(" ");
 510
 511         return validate_arguments ();
 512 }
 513
 514
 515
 516 int
 517 validate_arguments (void)
 518 {
 519         return OK;
 520 }
 521
 522
 523
 524 void
 525 print_help (void)
 526 {
 527         char *myport;
 528         asprintf (&myport, "%d", SMTP_PORT);
 529
 530         print_revision (progname, revision);
 531
 532         printf ("Copyright (c) 1999-2001 Ethan Galstad <nagios@nagios.org>\n");
 533         printf (COPYRIGHT, copyright, email);
 534
 535         printf(_("This plugin will attempt to open an SMTP connection with the host.\n\n"));
 536
 537         print_usage ();
 538
 539         printf (_(UT_HELP_VRSN));
 540
 541         printf (_(UT_HOST_PORT), 'p', myport);
 542
 543         printf (_(UT_IPv46));
 544
 545         printf (_("\
 546  -e, --expect=STRING\n\
 547    String to expect in first line of server response (default: '%s')\n\
 548  -n, nocommand\n\
 549    Suppress SMTP command\n\
 550  -C, --command=STRING\n\
 551    SMTP command (may be used repeatedly)\n\
 552  -R, --command=STRING\n\
 553    Expected response to command (may be used repeatedly)\n\
 554  -f, --from=STRING\n\
 555    FROM-address to include in MAIL command, required by Exchange 2000\n"),
 556                 SMTP_EXPECT);
 557 #ifdef HAVE_SSL
 558         printf (_("\
 559  -D, --certificate=INTEGER\n\
 560     Minimum number of days a certificate has to be valid.\n\
 561  -S, --starttls\n\
 562     Use STARTTLS for the connection.\n"));
 563 #endif
 564
 565         printf (_(UT_WARN_CRIT));
 566
 567         printf (_(UT_TIMEOUT), DEFAULT_SOCKET_TIMEOUT);
 568
 569         printf (_(UT_VERBOSE));
 570
 571         printf(_("\n\
 572 Successul connects return STATE_OK, refusals and timeouts return\n\
 573 STATE_CRITICAL, other errors return STATE_UNKNOWN.  Successful\n\
 574 connects, but incorrect reponse messages from the host result in\n\
 575 STATE_WARNING return values.\n"));
 576
 577         printf (_(UT_SUPPORT));
 578 }
 579
 580
 581
 582 void
 583 print_usage (void)
 584 {
 585         printf ("\
 586 Usage: %s -H host [-p port] [-e expect] [-C command] [-f from addr]\n\
 587                   [-w warn] [-c crit] [-t timeout] [-S] [-D days] [-n] [-v] [-4|-6]\n", progname);
 588 }
 589
 590 int
 591 my_close (void)
 592 {
 593 #ifdef HAVE_SSL
 594         np_net_ssl_cleanup();
 595 #endif
 596         return close(sd);
 597 }