main.c

   1 /******************************************************************************
   2  * Filename: main.c
   3  * Description:
   4  *
   5  * Version: 1.0
   6  * Created: Oct 09 2010 19:14:12
   7  * Last modified: Oct 09 2010 19:14:12
   8  *
   9  * Author: Ladislav Láska
  10  * e-mail: ladislav.laska@gmail.com
  11  *
  12  ******************************************************************************/
  13
  14 #define _XOPEN_SOURCE 500
  15
  16 #include <gnutls/gnutls.h>
  17 #include <gnutls/x509.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <sys/types.h>
  21 #include <sys/socket.h>
  22 #include <netdb.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <time.h>
  26 #include <signal.h>
  27
  28 #define S_UNREACHABLE -1
  29 #define S_NO_X509 -2
  30 #define S_OK 0
  31 #define S_WARNING 1
  32 #define S_ERROR 2
  33 #define S_UNKNOWN 3
  34
  35 int warning_after = 30;
  36 int error_after = 7;
  37 int verbose = 0;
  38
  39 #define LOG_LEVEL 0
  40
  41 #define die(msg) { fprintf(stderr, "Error: " msg "\n" ); exit(3); }
  42 #define gnutls_die(code) { gnutls_perror(code); exit(3); }
  43
  44 char errmsg[256];
  45
  46 void print_help();
  47
  48 int tcp_open( char *hostname, char *service ) {
  49         struct addrinfo hints;
  50         struct addrinfo *result, *result_ptr;
  51         int err, sfd;
  52
  53         /* Set hints */
  54         memset(&hints, 0, sizeof(struct addrinfo));
  55         hints.ai_family = AF_UNSPEC;
  56         hints.ai_socktype = SOCK_STREAM;
  57         err = getaddrinfo(hostname, service, &hints, &result);
  58         if (err) {
  59                 fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err));
  60                 exit(3);
  61         }
  62
  63         for (result_ptr = result; result_ptr != NULL; result_ptr = result_ptr->ai_next) {
  64                 sfd = socket(result_ptr->ai_family, result_ptr->ai_socktype,
  65                                                 result_ptr->ai_protocol);
  66                 if (sfd == -1) continue;
  67
  68                 if (connect(sfd, result_ptr->ai_addr, result_ptr->ai_addrlen) != -1)
  69                         break; /* Success */
  70
  71                 close(sfd);     /* connect(2) failed. */
  72         }
  73
  74         if (result_ptr == NULL) {
  75                 /* No address succeeded */
  76                 return -1;
  77         }
  78
  79         freeaddrinfo(result);
  80
  81         return sfd;
  82 }
  83
  84 int check( char * hostname, char *service ) {
  85         int state = S_OK;
  86         int err;
  87
  88         gnutls_session_t session;
  89         gnutls_certificate_credentials_t xcred;
  90
  91         /* x509 stuff */
  92
  93         err = gnutls_certificate_allocate_credentials( &xcred );
  94         if (err < 0) gnutls_die(err);
  95
  96         err = gnutls_init( &session, GNUTLS_CLIENT );
  97         if (err < 0) gnutls_die(err);
  98
  99         /* priority init? */
 100         err = gnutls_priority_set_direct(session, "EXPORT", NULL);
 101         if (err < 0) gnutls_die(err);
 102
 103         err = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE, xcred );
 104         if (err < 0) gnutls_die(err);
 105
 106         /* Connect to server */
 107
 108         long fd = tcp_open( hostname, service );
 109
 110         if (fd == -1) {
 111                 state= S_UNREACHABLE;
 112                 goto cleanup;
 113         }
 114
 115         /* Socket opened, establish tls connection */
 116
 117         /* Associate socket with session */
 118         gnutls_transport_set_ptr( session, (gnutls_transport_ptr_t) fd );
 119
 120         /* Do handshake */
 121         err = gnutls_handshake( session );
 122         if (err < 0) gnutls_die(err);
 123
 124         /* Get server certificate. */
 125         const gnutls_datum_t *cert_list;
 126         unsigned int cert_list_size = 0;
 127         time_t expiration_time, today;
 128         gnutls_x509_crt_t cert;
 129
 130         if ( gnutls_certificate_type_get( session ) != GNUTLS_CRT_X509 ) {
 131                 state = S_NO_X509;
 132                 goto cleanup;
 133         }
 134
 135         cert_list = gnutls_certificate_get_peers( session, &cert_list_size );
 136
 137         today = time(NULL);
 138
 139         for (int i = 0; i < cert_list_size; i++) {
 140                 gnutls_x509_crt_init( &cert );
 141                 gnutls_x509_crt_import( cert, &cert_list[0], GNUTLS_X509_FMT_DER );
 142                 expiration_time = gnutls_x509_crt_get_expiration_time( cert );
 143                 int expires_in = (expiration_time - today) / 86400;
 144                 struct tm * t = gmtime( &expiration_time );
 145                 if ((state == S_OK) && (expires_in <= warning_after)) {
 146                         state = S_WARNING;
 147                         sprintf(errmsg, "Warning - Will expire in %i days (%i-%02i-%02i).", expires_in,
 148                                 t->tm_year+1900, t->tm_mon+1, t->tm_mday );
 149                 }
 150                 if ((state <= S_WARNING) && (expires_in <= error_after)) {
 151                         state = S_ERROR;
 152                         sprintf(errmsg, "Critical - Will expire in %i days (%i-%02i-%02i).", expires_in,
 153                                 t->tm_year+1900, t->tm_mon+1, t->tm_mday );
 154                 }
 155                 if (state == S_OK) {
 156                         sprintf(errmsg, "OK - Will expire in %i days (%i-%02i-%02i).", expires_in,
 157                                 t->tm_year+1900, t->tm_mon+1, t->tm_mday );
 158                 }
 159         }
 160
 161         /* Clean up */
 162         err = gnutls_bye( session, GNUTLS_SHUT_WR );
 163         if (err < 0) gnutls_die(err);
 164         close( fd );
 165         cleanup:
 166         gnutls_deinit( session );
 167         gnutls_certificate_free_credentials( xcred );
 168
 169         return state;
 170 }
 171
 172 void log_func( int level, char *msg ) {
 173         fprintf(stderr, "[%2i] %s", level, msg);
 174 }
 175
 176 /*
 177  * This signal handler is wrong, but it's just a failsafe.
 178  */
 179 void sig_handler(int k) {
 180         fputs("Timeout.", stderr);
 181         exit(S_UNKNOWN);
 182 }
 183
 184 int main(int argc, char **argv) {
 185         char *hostname;
 186         char *service = NULL;
 187
 188         int opt;
 189
 190         while ((opt = getopt(argc, argv, "hvw:c:H:p:s:")) != -1) {
 191                 switch (opt) {
 192                         case 'w':
 193                                 warning_after = atoi(optarg);
 194                                 break;
 195                         case 'c':
 196                                 error_after = atoi(optarg);
 197                                 break;
 198                         case 'H':
 199                                 hostname = strdup(optarg);
 200                                 break;
 201                         case 'p':
 202                         case 's':
 203                                 if (service != NULL) die("Only one service can be specified.");
 204                                 service = strdup(optarg);
 205                                 break;
 206                         case 'h':
 207                                 print_help();
 208                                 exit(0);
 209                         case 'v':
 210                                 verbose++;
 211                         default: break;
 212                 }
 213         }
 214
 215         if (argc <= 1) die("No address to try.");
 216
 217         gnutls_global_set_log_function((gnutls_log_func) log_func);
 218         gnutls_global_set_log_level(LOG_LEVEL);
 219
 220
 221         /* Initialize gnutls */
 222         int err;
 223         if ((err = gnutls_global_init())) {
 224                 gnutls_perror(err);
 225                 exit(3);
 226         };
 227
 228         sprintf(errmsg, "OK");
 229         int state = 0;
 230
 231         fflush(stdout);
 232
 233         /* Setup alarm */
 234         /* TODO: doesn't work. */
 235         signal(SIGALRM, sig_handler);
 236         alarm(9*60);
 237
 238         /* Do checking */
 239         state = check(hostname, service);
 240         if (state < 0)
 241                 printf("Internal error.");
 242
 243         gnutls_global_deinit();
 244
 245         free(hostname);
 246         free(service);
 247
 248         printf("%s\n", errmsg);
 249         return (state < 0) ? 127 : state;
 250 }
 251
 252 void print_help() {
 253         printf(
 254                 "Usage: cert-checker [options] -H hostname -p|s port|service\n"
 255                 "  Where options could be: \n"
 256                 "       -h      this help\n"
 257                 "       -w      warning level (in days, default 30)\n"
 258                 "       -c      critical level (in days, default 7)\n"
 259                 "       -v      verbosity level\n"
 260         );
 261 }