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 int timeout = 9;
  39
  40 #define LOG_LEVEL 0
  41
  42 #define die(msg) { fprintf(stderr, "Error: " msg "\n" ); exit(3); }
  43 #define gnutls_die(code) { gnutls_perror(code); exit(3); }
  44
  45 char errmsg[256];
  46
  47 void print_help();
  48
  49 int tcp_open( char *hostname, char *service ) {
  50         struct addrinfo hints;
  51         struct addrinfo *result, *result_ptr;
  52         int err, sfd;
  53
  54         /* Set hints */
  55         memset(&hints, 0, sizeof(struct addrinfo));
  56         hints.ai_family = AF_UNSPEC;
  57         hints.ai_socktype = SOCK_STREAM;
  58         err = getaddrinfo(hostname, service, &hints, &result);
  59         if (err) {
  60                 fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err));
  61                 exit(3);
  62         }
  63
  64         for (result_ptr = result; result_ptr != NULL; result_ptr = result_ptr->ai_next) {
  65                 sfd = socket(result_ptr->ai_family, result_ptr->ai_socktype,
  66                                                 result_ptr->ai_protocol);
  67                 if (sfd == -1) continue;
  68
  69                 if (connect(sfd, result_ptr->ai_addr, result_ptr->ai_addrlen) != -1)
  70                         break; /* Success */
  71
  72                 close(sfd);     /* connect(2) failed. */
  73         }
  74
  75         if (result_ptr == NULL) {
  76                 /* No address succeeded */
  77                 return -1;
  78         }
  79
  80         freeaddrinfo(result);
  81
  82         return sfd;
  83 }
  84
  85 int check( char * hostname, char *service ) {
  86         int state = S_OK;
  87         int err;
  88
  89         gnutls_session_t session;
  90         gnutls_certificate_credentials_t xcred;
  91
  92         /* x509 stuff */
  93
  94         err = gnutls_certificate_allocate_credentials( &xcred );
  95         if (err < 0) gnutls_die(err);
  96
  97         err = gnutls_init( &session, GNUTLS_CLIENT );
  98         if (err < 0) gnutls_die(err);
  99
 100         /* priority init? */
 101         err = gnutls_priority_set_direct(session, "EXPORT", NULL);
 102         if (err < 0) gnutls_die(err);
 103
 104         err = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE, xcred );
 105         if (err < 0) gnutls_die(err);
 106
 107         /* Connect to server */
 108
 109         long fd = tcp_open( hostname, service );
 110
 111         if (fd == -1) {
 112                 state= S_UNREACHABLE;
 113                 goto cleanup;
 114         }
 115
 116         /* Socket opened, establish tls connection */
 117
 118         /* Associate socket with session */
 119         gnutls_transport_set_ptr( session, (gnutls_transport_ptr_t) fd );
 120
 121         /* Do handshake */
 122         err = gnutls_handshake( session );
 123         if (err < 0) gnutls_die(err);
 124
 125         /* Get server certificate. */
 126         const gnutls_datum_t *cert_list;
 127         unsigned int cert_list_size = 0;
 128         time_t expiration_time, today;
 129         gnutls_x509_crt_t cert;
 130
 131         if ( gnutls_certificate_type_get( session ) != GNUTLS_CRT_X509 ) {
 132                 state = S_NO_X509;
 133                 goto cleanup;
 134         }
 135
 136         cert_list = gnutls_certificate_get_peers( session, &cert_list_size );
 137
 138         today = time(NULL);
 139
 140         for (int i = 0; i < cert_list_size; i++) {
 141                 gnutls_x509_crt_init( &cert );
 142                 gnutls_x509_crt_import( cert, &cert_list[0], GNUTLS_X509_FMT_DER );
 143                 expiration_time = gnutls_x509_crt_get_expiration_time( cert );
 144                 int expires_in = (expiration_time - today) / 86400;
 145                 struct tm * t = gmtime( &expiration_time );
 146                 if ((state == S_OK) && (expires_in <= warning_after)) {
 147                         state = S_WARNING;
 148                         sprintf(errmsg, "Warning - Will expire in %i days (%i-%02i-%02i).", expires_in,
 149                                 t->tm_year+1900, t->tm_mon+1, t->tm_mday );
 150                 }
 151                 if ((state <= S_WARNING) && (expires_in <= error_after)) {
 152                         state = S_ERROR;
 153                         sprintf(errmsg, "Critical - Will expire in %i days (%i-%02i-%02i).", expires_in,
 154                                 t->tm_year+1900, t->tm_mon+1, t->tm_mday );
 155                 }
 156                 if (state == S_OK) {
 157                         sprintf(errmsg, "OK - Will expire in %i days (%i-%02i-%02i).", expires_in,
 158                                 t->tm_year+1900, t->tm_mon+1, t->tm_mday );
 159                 }
 160         }
 161
 162         /* Clean up */
 163         err = gnutls_bye( session, GNUTLS_SHUT_WR );
 164         if (err < 0) gnutls_die(err);
 165         close( fd );
 166         cleanup:
 167         gnutls_deinit( session );
 168         gnutls_certificate_free_credentials( xcred );
 169
 170         return state;
 171 }
 172
 173 void log_func( int level, char *msg ) {
 174         fprintf(stderr, "[%2i] %s", level, msg);
 175 }
 176
 177 /*
 178  * This signal handler is wrong, but it's just a failsafe.
 179  */
 180 void sig_handler(int k) {
 181         fputs("Timeout.\n", stderr);
 182         exit(S_UNKNOWN);
 183 }
 184
 185 int main(int argc, char **argv) {
 186         char *hostname;
 187         char *service = NULL;
 188
 189         int opt;
 190
 191         while ((opt = getopt(argc, argv, "hvw:c:H:p:s:t:")) != -1) {
 192                 switch (opt) {
 193                         case 'w':
 194                                 warning_after = atoi(optarg);
 195                                 break;
 196                         case 'c':
 197                                 error_after = atoi(optarg);
 198                                 break;
 199                         case 'H':
 200                                 hostname = strdup(optarg);
 201                                 break;
 202                         case 't':
 203                                 timeout = atoi( optarg );
 204                                 if (timeout < 0) die("Timeout must be >= 0");
 205                                 break;
 206                         case 'p':
 207                         case 's':
 208                                 if (service != NULL) die("Only one service can be specified.");
 209                                 service = strdup(optarg);
 210                                 break;
 211                         case 'h':
 212                                 print_help();
 213                                 exit(0);
 214                         case 'v':
 215                                 verbose++;
 216                         default: break;
 217                 }
 218         }
 219
 220         if (argc <= 1) die("No address to try.");
 221
 222         gnutls_global_set_log_function((gnutls_log_func) log_func);
 223         gnutls_global_set_log_level(LOG_LEVEL);
 224
 225
 226         /* Initialize gnutls */
 227         int err;
 228         if ((err = gnutls_global_init())) {
 229                 gnutls_perror(err);
 230                 exit(3);
 231         };
 232
 233         sprintf(errmsg, "OK");
 234         int state = 0;
 235
 236         fflush(stdout);
 237
 238         /* Setup alarm */
 239         /* TODO: doesn't work. */
 240         signal(SIGALRM, sig_handler);
 241         alarm( timeout );
 242
 243         /* Do checking */
 244         state = check(hostname, service);
 245         if (state < 0) {
 246                 sprintf(errmsg, "Internal error %i.", state);
 247                 state = S_UNKNOWN;
 248         }
 249
 250         gnutls_global_deinit();
 251
 252         free(hostname);
 253         free(service);
 254
 255         printf("%s\n", errmsg);
 256         return (state < 0) ? 127 : state;
 257 }
 258
 259 void print_help() {
 260         printf(
 261                 "Usage: cert-checker [options] -H hostname -p|s port|service\n"
 262                 "  Where options could be: \n"
 263                 "       -h hostname   this help\n"
 264                 "       -w n          warning level (in days, default 30)\n"
 265                 "       -c n          critical level (in days, default 7)\n"
 266                 "       -v            verbosity level\n"
 267                 "       -t n          timeout (in seconds, n=0 disables timeout\n"
 268         );
 269 }