plugins/check_ssh.c

   1 /*****************************************************************************
   2 *
   3 * Nagios check_ssh plugin
   4 *
   5 * License: GPL
   6 * Copyright (c) 2000-2007 Nagios Plugins Development Team
   7 *
   8 * Description:
   9 *
  10 * This file contains the check_ssh plugin
  11 *
  12 * Try to connect to an SSH server at specified server and port
  13 *
  14 *
  15 * This program is free software: you can redistribute it and/or modify
  16 * it under the terms of the GNU General Public License as published by
  17 * the Free Software Foundation, either version 3 of the License, or
  18 * (at your option) any later version.
  19 *
  20 * This program is distributed in the hope that it will be useful,
  21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 * GNU General Public License for more details.
  24 *
  25 * You should have received a copy of the GNU General Public License
  26 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  27 *
  28 *
  29 *****************************************************************************/
  30
  31 const char *progname = "check_ssh";
  32 const char *copyright = "2000-2007";
  33 const char *email = "nagiosplug-devel@lists.sourceforge.net";
  34
  35 #include "common.h"
  36 #include "netutils.h"
  37 #include "utils.h"
  38
  39 #ifndef MSG_DONTWAIT
  40 #define MSG_DONTWAIT 0
  41 #endif
  42
  43 #define SSH_DFL_PORT    22
  44 #define BUFF_SZ         256
  45
  46 int port = -1;
  47 char *server_name = NULL;
  48 char *remote_version = NULL;
  49 int verbose = FALSE;
  50
  51 int process_arguments (int, char **);
  52 int validate_arguments (void);
  53 void print_help (void);
  54 void print_usage (void);
  55
  56 int ssh_connect (char *haddr, int hport, char *remote_version);
  57
  58
  59
  60 int
  61 main (int argc, char **argv)
  62 {
  63         int result = STATE_UNKNOWN;
  64
  65         setlocale (LC_ALL, "");
  66         bindtextdomain (PACKAGE, LOCALEDIR);
  67         textdomain (PACKAGE);
  68
  69         /* Parse extra opts if any */
  70         argv=np_extra_opts (&argc, argv, progname);
  71
  72         if (process_arguments (argc, argv) == ERROR)
  73                 usage4 (_("Could not parse arguments"));
  74
  75         /* initialize alarm signal handling */
  76         signal (SIGALRM, socket_timeout_alarm_handler);
  77
  78         alarm (socket_timeout);
  79
  80         /* ssh_connect exits if error is found */
  81         result = ssh_connect (server_name, port, remote_version);
  82
  83         alarm (0);
  84
  85         return (result);
  86 }
  87
  88
  89
  90 /* process command-line arguments */
  91 int
  92 process_arguments (int argc, char **argv)
  93 {
  94         int c;
  95
  96         int option = 0;
  97         static struct option longopts[] = {
  98                 {"help", no_argument, 0, 'h'},
  99                 {"version", no_argument, 0, 'V'},
 100                 {"host", required_argument, 0, 'H'},    /* backward compatibility */
 101                 {"hostname", required_argument, 0, 'H'},
 102                 {"port", required_argument, 0, 'p'},
 103                 {"use-ipv4", no_argument, 0, '4'},
 104                 {"use-ipv6", no_argument, 0, '6'},
 105                 {"timeout", required_argument, 0, 't'},
 106                 {"verbose", no_argument, 0, 'v'},
 107                 {"remote-version", required_argument, 0, 'r'},
 108                 {0, 0, 0, 0}
 109         };
 110
 111         if (argc < 2)
 112                 return ERROR;
 113
 114         for (c = 1; c < argc; c++)
 115                 if (strcmp ("-to", argv[c]) == 0)
 116                         strcpy (argv[c], "-t");
 117
 118         while (1) {
 119                 c = getopt_long (argc, argv, "+Vhv46t:r:H:p:", longopts, &option);
 120
 121                 if (c == -1 || c == EOF)
 122                         break;
 123
 124                 switch (c) {
 125                 case '?':                                                                       /* help */
 126                         usage5 ();
 127                 case 'V':                                                                       /* version */
 128                         print_revision (progname, NP_VERSION);
 129                         exit (STATE_OK);
 130                 case 'h':                                                                       /* help */
 131                         print_help ();
 132                         exit (STATE_OK);
 133                 case 'v':                                                                       /* verbose */
 134                         verbose = TRUE;
 135                         break;
 136                 case 't':                                                                       /* timeout period */
 137                         if (!is_integer (optarg))
 138                                 usage2 (_("Timeout interval must be a positive integer"), optarg);
 139                         else
 140                                 socket_timeout = atoi (optarg);
 141                         break;
 142                 case '4':
 143                         address_family = AF_INET;
 144                         break;
 145                 case '6':
 146 #ifdef USE_IPV6
 147                         address_family = AF_INET6;
 148 #else
 149                         usage4 (_("IPv6 support not available"));
 150 #endif
 151                         break;
 152                 case 'r':                                                                       /* remote version */
 153                         remote_version = optarg;
 154                         break;
 155                 case 'H':                                                                       /* host */
 156                         if (is_host (optarg) == FALSE)
 157                                 usage2 (_("Invalid hostname/address"), optarg);
 158                         server_name = optarg;
 159                         break;
 160                 case 'p':                                                                       /* port */
 161                         if (is_intpos (optarg)) {
 162                                 port = atoi (optarg);
 163                         }
 164                         else {
 165                                 usage2 (_("Port number must be a positive integer"), optarg);
 166                         }
 167                 }
 168         }
 169
 170         c = optind;
 171         if (server_name == NULL && c < argc) {
 172                 if (is_host (argv[c])) {
 173                         server_name = argv[c++];
 174                 }
 175         }
 176
 177         if (port == -1 && c < argc) {
 178                 if (is_intpos (argv[c])) {
 179                         port = atoi (argv[c++]);
 180                 }
 181                 else {
 182                         print_usage ();
 183                         exit (STATE_UNKNOWN);
 184                 }
 185         }
 186
 187         return validate_arguments ();
 188 }
 189
 190 int
 191 validate_arguments (void)
 192 {
 193         if (server_name == NULL)
 194                 return ERROR;
 195         if (port == -1)                                                         /* funky, but allows -p to override stray integer in args */
 196                 port = SSH_DFL_PORT;
 197         return OK;
 198 }
 199
 200
 201 /************************************************************************
 202 *
 203 * Try to connect to SSH server at specified server and port
 204 *
 205 *-----------------------------------------------------------------------*/
 206
 207
 208 int
 209 ssh_connect (char *haddr, int hport, char *remote_version)
 210 {
 211         int sd;
 212         int result;
 213         char *output = NULL;
 214         char *buffer = NULL;
 215         char *ssh_proto = NULL;
 216         char *ssh_server = NULL;
 217         static char *rev_no = VERSION;
 218
 219         result = my_tcp_connect (haddr, hport, &sd);
 220
 221         if (result != STATE_OK)
 222                 return result;
 223
 224         output = (char *) malloc (BUFF_SZ + 1);
 225         memset (output, 0, BUFF_SZ + 1);
 226         recv (sd, output, BUFF_SZ, 0);
 227         if (strncmp (output, "SSH", 3)) {
 228                 printf (_("Server answer: %s"), output);
 229                 close(sd);
 230                 exit (STATE_CRITICAL);
 231         }
 232         else {
 233                 strip (output);
 234                 if (verbose)
 235                         printf ("%s\n", output);
 236                 ssh_proto = output + 4;
 237                 ssh_server = ssh_proto + strspn (ssh_proto, "-0123456789. ");
 238                 ssh_proto[strspn (ssh_proto, "0123456789. ")] = 0;
 239
 240                 asprintf (&buffer, "SSH-%s-check_ssh_%s\r\n", ssh_proto, rev_no);
 241                 send (sd, buffer, strlen (buffer), MSG_DONTWAIT);
 242                 if (verbose)
 243                         printf ("%s\n", buffer);
 244
 245                 if (remote_version && strcmp(remote_version, ssh_server)) {
 246                         printf
 247                                 (_("SSH WARNING - %s (protocol %s) version mismatch, expected '%s'\n"),
 248                                  ssh_server, ssh_proto, remote_version);
 249                         close(sd);
 250                         exit (STATE_WARNING);
 251                 }
 252
 253                 printf
 254                         (_("SSH OK - %s (protocol %s)\n"),
 255                          ssh_server, ssh_proto);
 256                 close(sd);
 257                 exit (STATE_OK);
 258         }
 259 }
 260
 261
 262
 263 void
 264 print_help (void)
 265 {
 266         char *myport;
 267         asprintf (&myport, "%d", SSH_DFL_PORT);
 268
 269         print_revision (progname, NP_VERSION);
 270
 271         printf ("Copyright (c) 1999 Remi Paulmier <remi@sinfomic.fr>\n");
 272         printf (COPYRIGHT, copyright, email);
 273
 274         printf ("%s\n", _("Try to connect to an SSH server at specified server and port"));
 275
 276   printf ("\n\n");
 277
 278         print_usage ();
 279
 280         printf (UT_HELP_VRSN);
 281         printf (UT_EXTRA_OPTS);
 282
 283         printf (UT_HOST_PORT, 'p', myport);
 284
 285         printf (UT_IPv46);
 286
 287         printf (UT_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);
 288
 289         printf (" %s\n", "-r, --remote-version=STRING");
 290   printf ("    %s\n", _("Warn if string doesn't match expected server version (ex: OpenSSH_3.9p1)"));
 291
 292         printf (UT_VERBOSE);
 293
 294         printf (UT_SUPPORT);
 295 }
 296
 297
 298
 299 void
 300 print_usage (void)
 301 {
 302   printf ("%s\n", _("Usage:"));
 303         printf ("%s [-46] [-t <timeout>] [-r <remote version>] [-p <port>] <host>\n", progname);
 304 }
 305