plugins/sslutils.c

   1 /*****************************************************************************
   2 *
   3 * Nagios plugins SSL utilities
   4 *
   5 * License: GPL
   6 * Copyright (c) 2005-2010 Nagios Plugins Development Team
   7 *
   8 * Description:
   9 *
  10 * This file contains common functions for plugins that require SSL.
  11 *
  12 *
  13 * This program is free software: you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation, either version 3 of the License, or
  16 * (at your option) any later version.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 *
  23 * You should have received a copy of the GNU General Public License
  24 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  25 *
  26 *
  27 *****************************************************************************/
  28
  29 #define MAX_CN_LENGTH 256
  30 #define LOCAL_TIMEOUT_ALARM_HANDLER
  31 #include "common.h"
  32 #include "netutils.h"
  33
  34 #ifdef HAVE_SSL
  35 static SSL_CTX *c=NULL;
  36 static SSL *s=NULL;
  37 static int initialized=0;
  38
  39 int np_net_ssl_init(int sd) {
  40         return np_net_ssl_init_with_hostname(sd, NULL);
  41 }
  42
  43 int np_net_ssl_init_with_hostname(int sd, char *host_name) {
  44         return np_net_ssl_init_with_hostname_and_version(sd, host_name, 0);
  45 }
  46
  47 int np_net_ssl_init_with_hostname_and_version(int sd, char *host_name, int version) {
  48         const SSL_METHOD *method = NULL;
  49
  50         switch (version) {
  51         case 0: /* Deafult to auto negotiation */
  52                 method = SSLv23_client_method();
  53                 break;
  54         case 1: /* TLSv1 protocol */
  55                 method = TLSv1_client_method();
  56                 break;
  57         case 2: /* SSLv2 protocol */
  58 #if defined(USE_GNUTLS) || defined(OPENSSL_NO_SSL2)
  59                 printf(("%s\n", _("CRITICAL - SSL protocol version 2 is not supported by your SSL library.")));
  60                 return STATE_CRITICAL;
  61 #else
  62                 method = SSLv2_client_method();
  63 #endif
  64                 break;
  65         case 3: /* SSLv3 protocol */
  66                 method = SSLv3_client_method();
  67                 break;
  68         default: /* Unsupported */
  69                 printf("%s\n", _("CRITICAL - Unsupported SSL protocol version."));
  70                 return STATE_CRITICAL;
  71         }
  72         if (!initialized) {
  73                 /* Initialize SSL context */
  74                 SSLeay_add_ssl_algorithms();
  75                 SSL_load_error_strings();
  76                 OpenSSL_add_all_algorithms();
  77                 initialized = 1;
  78         }
  79         if ((c = SSL_CTX_new(method)) == NULL) {
  80                 printf("%s\n", _("CRITICAL - Cannot create SSL context."));
  81                 return STATE_CRITICAL;
  82         }
  83 #ifdef SSL_OP_NO_TICKET
  84         SSL_CTX_set_options(c, SSL_OP_NO_TICKET);
  85 #endif
  86         if ((s = SSL_new(c)) != NULL) {
  87 #ifdef SSL_set_tlsext_host_name
  88                 if (host_name != NULL)
  89                         SSL_set_tlsext_host_name(s, host_name);
  90 #endif
  91                 SSL_set_fd(s, sd);
  92                 if (SSL_connect(s) == 1) {
  93                         return OK;
  94                 } else {
  95                         printf("%s\n", _("CRITICAL - Cannot make SSL connection."));
  96 #  ifdef USE_OPENSSL /* XXX look into ERR_error_string */
  97                         ERR_print_errors_fp(stdout);
  98 #  endif /* USE_OPENSSL */
  99                 }
 100         } else {
 101                         printf("%s\n", _("CRITICAL - Cannot initiate SSL handshake."));
 102         }
 103         return STATE_CRITICAL;
 104 }
 105
 106 void np_net_ssl_cleanup() {
 107         if (s) {
 108 #ifdef SSL_set_tlsext_host_name
 109                 SSL_set_tlsext_host_name(s, NULL);
 110 #endif
 111                 SSL_shutdown(s);
 112                 SSL_free(s);
 113                 if (c) {
 114                         SSL_CTX_free(c);
 115                         c=NULL;
 116                 }
 117                 s=NULL;
 118         }
 119 }
 120
 121 int np_net_ssl_write(const void *buf, int num) {
 122         return SSL_write(s, buf, num);
 123 }
 124
 125 int np_net_ssl_read(void *buf, int num) {
 126         return SSL_read(s, buf, num);
 127 }
 128
 129 int np_net_ssl_check_cert(int days_till_exp_warn, int days_till_exp_crit){
 130 #  ifdef USE_OPENSSL
 131         X509 *certificate=NULL;
 132         X509_NAME *subj=NULL;
 133         char cn[MAX_CN_LENGTH]= "";
 134         int cnlen =-1;
 135         int status=STATE_UNKNOWN;
 136
 137         ASN1_STRING *tm;
 138         int offset;
 139         struct tm stamp;
 140         float time_left;
 141         int days_left;
 142         char timestamp[17] = "";
 143
 144         certificate=SSL_get_peer_certificate(s);
 145         if (!certificate) {
 146                 printf("%s\n",_("CRITICAL - Cannot retrieve server certificate."));
 147                 return STATE_CRITICAL;
 148         }
 149
 150         /* Extract CN from certificate subject */
 151         subj=X509_get_subject_name(certificate);
 152
 153         if (!subj) {
 154                 printf("%s\n",_("CRITICAL - Cannot retrieve certificate subject."));
 155                 return STATE_CRITICAL;
 156         }
 157         cnlen = X509_NAME_get_text_by_NID(subj, NID_commonName, cn, sizeof(cn));
 158         if (cnlen == -1)
 159                 strcpy(cn, _("Unknown CN"));
 160
 161         /* Retrieve timestamp of certificate */
 162         tm = X509_get_notAfter(certificate);
 163
 164         /* Generate tm structure to process timestamp */
 165         if (tm->type == V_ASN1_UTCTIME) {
 166                 if (tm->length < 10) {
 167                         printf("%s\n", _("CRITICAL - Wrong time format in certificate."));
 168                         return STATE_CRITICAL;
 169                 } else {
 170                         stamp.tm_year = (tm->data[0] - '0') * 10 + (tm->data[1] - '0');
 171                         if (stamp.tm_year < 50)
 172                                 stamp.tm_year += 100;
 173                         offset = 0;
 174                 }
 175         } else {
 176                 if (tm->length < 12) {
 177                         printf("%s\n", _("CRITICAL - Wrong time format in certificate."));
 178                         return STATE_CRITICAL;
 179                 } else {
 180                         stamp.tm_year =
 181                                 (tm->data[0] - '0') * 1000 + (tm->data[1] - '0') * 100 +
 182                                 (tm->data[2] - '0') * 10 + (tm->data[3] - '0');
 183                         stamp.tm_year -= 1900;
 184                         offset = 2;
 185                 }
 186         }
 187         stamp.tm_mon =
 188                 (tm->data[2 + offset] - '0') * 10 + (tm->data[3 + offset] - '0') - 1;
 189         stamp.tm_mday =
 190                 (tm->data[4 + offset] - '0') * 10 + (tm->data[5 + offset] - '0');
 191         stamp.tm_hour =
 192                 (tm->data[6 + offset] - '0') * 10 + (tm->data[7 + offset] - '0');
 193         stamp.tm_min =
 194                 (tm->data[8 + offset] - '0') * 10 + (tm->data[9 + offset] - '0');
 195         stamp.tm_sec = 0;
 196         stamp.tm_isdst = -1;
 197
 198         time_left = difftime(timegm(&stamp), time(NULL));
 199         days_left = time_left / 86400;
 200         snprintf
 201                 (timestamp, 17, "%02d/%02d/%04d %02d:%02d",
 202                  stamp.tm_mon + 1,
 203                  stamp.tm_mday, stamp.tm_year + 1900, stamp.tm_hour, stamp.tm_min);
 204
 205         if (days_left > 0 && days_left <= days_till_exp_warn) {
 206                 printf (_("%s - Certificate '%s' expires in %d day(s) (%s).\n"), (days_left>days_till_exp_crit)?"WARNING":"CRITICAL", cn, days_left, timestamp);
 207                 if (days_left > days_till_exp_crit)
 208                         return STATE_WARNING;
 209                 else
 210                         return STATE_CRITICAL;
 211         } else if (time_left < 0) {
 212                 printf(_("CRITICAL - Certificate '%s' expired on %s.\n"), cn, timestamp);
 213                 status=STATE_CRITICAL;
 214         } else if (days_left == 0) {
 215                 printf (_("%s - Certificate '%s' expires today (%s).\n"), (days_left>days_till_exp_crit)?"WARNING":"CRITICAL", cn, timestamp);
 216                 if (days_left > days_till_exp_crit)
 217                         return STATE_WARNING;
 218                 else
 219                         return STATE_CRITICAL;
 220         } else {
 221                 printf(_("OK - Certificate '%s' will expire on %s.\n"), cn, timestamp);
 222                 status=STATE_OK;
 223         }
 224         X509_free(certificate);
 225         return status;
 226 #  else /* ifndef USE_OPENSSL */
 227         printf("%s\n", _("WARNING - Plugin does not support checking certificates."));
 228         return STATE_WARNING;
 229 #  endif /* USE_OPENSSL */
 230 }
 231
 232 #endif /* HAVE_SSL */