kuser/kimpersonate.c

   1 /*
   2  * Copyright (c) 2000 - 2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kuser_locl.h"
  35 #include <parse_units.h>
  36
  37 static char *client_principal_str = NULL;
  38 static krb5_principal client_principal;
  39 static char *server_principal_str = NULL;
  40 static krb5_principal server_principal;
  41
  42 static char *ccache_str = NULL;
  43
  44 static char *ticket_flags_str = NULL;
  45 static TicketFlags ticket_flags;
  46 static char *keytab_file = NULL;
  47 static char *enctype_string = NULL;
  48 static char *session_enctype_string = NULL;
  49 static int   expiration_time = 3600;
  50 static struct getarg_strings client_addresses;
  51 static int   version_flag = 0;
  52 static int   help_flag = 0;
  53 static int   use_krb5 = 1;
  54 static int   add_to_ccache = 0;
  55 static int   use_referral_realm = 0;
  56
  57 static const char *enc_type = "aes256-cts-hmac-sha1-96";
  58 static const char *session_enc_type = NULL;
  59
  60 static void
  61 encode_ticket(krb5_context context,
  62               EncryptionKey *skey,
  63               krb5_enctype etype,
  64               int skvno,
  65               krb5_creds *cred)
  66 {
  67     size_t len, size;
  68     char *buf;
  69     krb5_error_code ret;
  70     krb5_crypto crypto;
  71     EncryptedData enc_part;
  72     EncTicketPart et;
  73     Ticket ticket;
  74
  75     memset(&enc_part, 0, sizeof(enc_part));
  76     memset(&ticket, 0, sizeof(ticket));
  77
  78     /*
  79      * Set up `enc_part'
  80      */
  81
  82     et.flags = cred->flags.b;
  83     et.key = cred->session;
  84     et.crealm = cred->client->realm;
  85     et.cname = cred->client->name;
  86     {
  87         krb5_data empty_string;
  88
  89         krb5_data_zero(&empty_string);
  90         et.transited.tr_type = domain_X500_Compress;
  91         et.transited.contents = empty_string;
  92     }
  93     et.authtime = cred->times.authtime;
  94     et.starttime = NULL;
  95     et.endtime = cred->times.endtime;
  96     et.renew_till = NULL;
  97     et.caddr = &cred->addresses;
  98     et.authorization_data = NULL; /* XXX allow random authorization_data */
  99
 100     /*
 101      * Encrypt `enc_part' of ticket with service key
 102      */
 103
 104     ASN1_MALLOC_ENCODE(EncTicketPart, buf, len, &et, &size, ret);
 105     if (ret)
 106         krb5_err(context, 1, ret, "EncTicketPart");
 107
 108     ret = krb5_crypto_init(context, skey, etype, &crypto);
 109     if (ret)
 110         krb5_err(context, 1, ret, "krb5_crypto_init");
 111     ret = krb5_encrypt_EncryptedData(context,
 112                                       crypto,
 113                                       KRB5_KU_TICKET,
 114                                       buf,
 115                                       len,
 116                                       skvno,
 117                                       &ticket.enc_part);
 118     if (ret)
 119         krb5_err(context, 1, ret, "krb5_encrypt_EncryptedData");
 120
 121     free(buf);
 122     krb5_crypto_destroy(context, crypto);
 123
 124     /*
 125      * Encode ticket
 126      */
 127
 128     ticket.tkt_vno = 5;
 129     ticket.realm = cred->server->realm;
 130     ticket.sname = cred->server->name;
 131     ASN1_MALLOC_ENCODE(Ticket, cred->ticket.data, cred->ticket.length, &ticket, &size, ret);
 132     free_EncryptedData(&ticket.enc_part);
 133     if(ret)
 134         krb5_err(context, 1, ret, "encode_Ticket");
 135 }
 136
 137 /*
 138  *
 139  */
 140
 141 static int
 142 create_krb5_tickets(krb5_context context, krb5_keytab kt)
 143 {
 144     krb5_error_code ret;
 145     krb5_keytab_entry entry;
 146     krb5_creds cred;
 147     krb5_enctype etype;
 148     krb5_enctype session_etype;
 149     krb5_ccache ccache;
 150
 151     memset(&cred, 0, sizeof(cred));
 152
 153     ret = krb5_string_to_enctype(context, enc_type, &etype);
 154     if (ret)
 155         krb5_err (context, 1, ret, "krb5_string_to_enctype (enc-type)");
 156     ret = krb5_string_to_enctype(context, session_enc_type, &session_etype);
 157     if (ret)
 158         krb5_err (context, 1, ret, "krb5_string_to_enctype (session-enc-type)");
 159     ret = krb5_kt_get_entry(context, kt, server_principal, 0, etype, &entry);
 160     if (ret)
 161         krb5_err(context, 1, ret, "krb5_kt_get_entry (perhaps use different --enc-type)");
 162
 163     /*
 164      * setup cred
 165      */
 166
 167
 168     ret = krb5_copy_principal(context, client_principal, &cred.client);
 169     if (ret == 0)
 170         ret = krb5_copy_principal(context, server_principal, &cred.server);
 171     if (ret)
 172         krb5_err(context, 1, ret, "krb5_copy_principal");
 173     ret = krb5_generate_random_keyblock(context, session_etype, &cred.session);
 174     if (ret)
 175         krb5_err(context, 1, ret, "krb5_generate_random_keyblock");
 176
 177     cred.times.authtime = time(NULL);
 178     cred.times.starttime = time(NULL);
 179     cred.times.endtime = time(NULL) + expiration_time;
 180     cred.times.renew_till = 0;
 181     krb5_data_zero(&cred.second_ticket);
 182
 183     ret = krb5_get_all_client_addrs(context, &cred.addresses);
 184     if (ret)
 185         krb5_err(context, 1, ret, "krb5_get_all_client_addrs");
 186     cred.flags.b = ticket_flags;
 187
 188
 189     /*
 190      * Encode encrypted part of ticket
 191      */
 192
 193     encode_ticket(context, &entry.keyblock, etype, entry.vno, &cred);
 194     krb5_kt_free_entry(context, &entry);
 195
 196     /*
 197      * Write to cc
 198      */
 199
 200     if (ccache_str) {
 201         ret = krb5_cc_resolve(context, ccache_str, &ccache);
 202         if (ret)
 203             krb5_err(context, 1, ret, "krb5_cc_resolve");
 204     } else {
 205         ret = krb5_cc_default(context, &ccache);
 206         if (ret)
 207             krb5_err(context, 1, ret, "krb5_cc_default");
 208     }
 209
 210     if (add_to_ccache) {
 211         krb5_principal def_princ = NULL;
 212
 213         /*
 214          * Force fcache to read the ccache header, otherwise the store
 215          * will fail.
 216          */
 217         ret = krb5_cc_get_principal(context, ccache, &def_princ);
 218         if (ret) {
 219             krb5_warn(context, ret,
 220                       "Given ccache appears not to exist; initializing it");
 221             ret = krb5_cc_initialize(context, ccache, cred.client);
 222             if (ret)
 223                 krb5_err(context, 1, ret, "krb5_cc_initialize");
 224         }
 225         krb5_free_principal(context, def_princ);
 226     } else {
 227         ret = krb5_cc_initialize(context, ccache, cred.client);
 228         if (ret)
 229             krb5_err(context, 1, ret, "krb5_cc_initialize");
 230     }
 231
 232     if (use_referral_realm &&
 233         strcmp(krb5_principal_get_realm(context, cred.server), "") != 0) {
 234         krb5_free_principal(context, cred.server);
 235         ret = krb5_copy_principal(context, server_principal, &cred.server);
 236         if (ret)
 237             krb5_err(context, 1, ret, "krb5_copy_principal");
 238         ret = krb5_principal_set_realm(context, cred.server, "");
 239         if (ret)
 240             krb5_err(context, 1, ret, "krb5_principal_set_realm");
 241         ret = krb5_cc_store_cred(context, ccache, &cred);
 242         if (ret)
 243             krb5_err(context, 1, ret, "krb5_cc_store_cred");
 244
 245         krb5_free_principal(context, cred.server);
 246         ret = krb5_copy_principal(context, server_principal, &cred.server);
 247         if (ret)
 248             krb5_err(context, 1, ret, "krb5_copy_principal");
 249     }
 250     ret = krb5_cc_store_cred(context, ccache, &cred);
 251     if (ret)
 252         krb5_err(context, 1, ret, "krb5_cc_store_cred");
 253
 254     krb5_free_cred_contents(context, &cred);
 255     krb5_cc_close(context, ccache);
 256
 257     return 0;
 258 }
 259
 260 /*
 261  *
 262  */
 263
 264 static void
 265 setup_env(krb5_context context, krb5_keytab *kt)
 266 {
 267     krb5_error_code ret;
 268
 269     if (keytab_file)
 270         ret = krb5_kt_resolve(context, keytab_file, kt);
 271     else
 272         ret = krb5_kt_default(context, kt);
 273     if (ret)
 274         krb5_err(context, 1, ret, "resolving keytab");
 275
 276     if (client_principal_str == NULL)
 277         krb5_errx(context, 1, "missing client principal");
 278     ret = krb5_parse_name(context, client_principal_str, &client_principal);
 279     if (ret)
 280         krb5_err(context, 1, ret, "resolvning client name");
 281
 282     if (server_principal_str == NULL)
 283         krb5_errx(context, 1, "missing server principal");
 284     ret = krb5_parse_name(context, server_principal_str, &server_principal);
 285     if (ret)
 286         krb5_err(context, 1, ret, "resolvning server name");
 287
 288     /* If no session-enc-type specified on command line and this is an afs */
 289     /* service ticket, change default of session_enc_type to DES.       */
 290     if (session_enctype_string == NULL
 291         && strcmp("afs", *server_principal->name.name_string.val) == 0)
 292         session_enc_type = "des-cbc-crc";
 293
 294     if (ticket_flags_str) {
 295         int ticket_flags_int;
 296
 297         ticket_flags_int = parse_flags(ticket_flags_str,
 298                                        asn1_TicketFlags_units(), 0);
 299         if (ticket_flags_int <= 0) {
 300             krb5_warnx(context, "bad ticket flags: `%s'", ticket_flags_str);
 301             print_flags_table(asn1_TicketFlags_units(), stderr);
 302             exit(1);
 303         }
 304         if (ticket_flags_int)
 305             ticket_flags = int2TicketFlags(ticket_flags_int);
 306     }
 307 }
 308
 309 /*
 310  *
 311  */
 312
 313 struct getargs args[] = {
 314     { "ccache", 0, arg_string, &ccache_str,
 315       "name of kerberos 5 credential cache", "cache-name"},
 316     { "server", 's', arg_string, &server_principal_str,
 317       "name of server principal", NULL },
 318     { "client", 'c', arg_string, &client_principal_str,
 319       "name of client principal", NULL },
 320     { "keytab", 'k', arg_string, &keytab_file,
 321       "name of keytab file", NULL },
 322     { "krb5", '5', arg_flag,     &use_krb5,
 323       "create a kerberos 5 ticket", NULL },
 324     { "add", 'A', arg_flag,      &add_to_ccache,
 325       "add to ccache without re-initializing it", NULL },
 326     { "referral", 'R', arg_flag,         &use_referral_realm,
 327       "store an additional entry for the service with the empty realm", NULL },
 328     { "expire-time", 'e', arg_integer, &expiration_time,
 329       "lifetime of ticket in seconds", NULL },
 330     { "client-addresses", 'a', arg_strings, &client_addresses,
 331       "addresses of client", NULL },
 332     { "enc-type", 't', arg_string,      &enctype_string,
 333       "encryption type", NULL },
 334     { "session-enc-type", 0, arg_string,&session_enctype_string,
 335       "encryption type", NULL },
 336     { "ticket-flags", 'f', arg_string,   &ticket_flags_str,
 337       "ticket flags for krb5 ticket", NULL },
 338     { "version", 0,  arg_flag,          &version_flag,  "Print version",
 339       NULL },
 340     { "help",    0,  arg_flag,          &help_flag,     NULL,
 341       NULL }
 342 };
 343
 344 static void
 345 usage(int ret)
 346 {
 347     arg_printusage(args,
 348                    sizeof(args) / sizeof(args[0]),
 349                    NULL,
 350                    "");
 351     exit(ret);
 352 }
 353
 354 int
 355 main(int argc, char **argv)
 356 {
 357     int optidx = 0;
 358     krb5_error_code ret;
 359     krb5_context context;
 360     krb5_keytab kt;
 361
 362     setprogname(argv[0]);
 363
 364     ret = krb5_init_context(&context);
 365     if (ret)
 366         errx(1, "krb5_init_context failed: %u", ret);
 367
 368     if (getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optidx))
 369         usage(1);
 370
 371     if (help_flag)
 372         usage(0);
 373
 374     if (version_flag) {
 375         print_version(NULL);
 376         return 0;
 377     }
 378
 379     if (enctype_string)
 380         enc_type = enctype_string;
 381     if (session_enctype_string)
 382         session_enc_type = session_enctype_string;
 383     else
 384         session_enc_type = enc_type;
 385
 386     setup_env(context, &kt);
 387
 388     if (use_krb5)
 389         create_krb5_tickets(context, kt);
 390
 391     krb5_kt_close(context, kt);
 392     krb5_free_context(context);
 393
 394     return 0;
 395 }