client/cifs.upcall.c

   1 /*
   2 * CIFS user-space helper.
   3 * Copyright (C) Igor Mammedov (niallain@gmail.com) 2007
   4 * Copyright (C) Jeff Layton (jlayton@redhat.com) 2009
   5 *
   6 * Used by /sbin/request-key for handling
   7 * cifs upcall for kerberos authorization of access to share and
   8 * cifs upcall for DFS srver name resolving (IPv4/IPv6 aware).
   9 * You should have keyutils installed and add something like the
  10 * following lines to /etc/request-key.conf file:
  11
  12 create cifs.spnego * * /usr/local/sbin/cifs.upcall %k
  13 create dns_resolver * * /usr/local/sbin/cifs.upcall %k
  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 2 of the License, or
  18 * (at your option) any later version.
  19 * This program is distributed in the hope that it will be useful,
  20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  22 * GNU General Public License for more details.
  23 * You should have received a copy of the GNU General Public License
  24 * along with this program; if not, write to the Free Software
  25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  26 */
  27
  28 #include "includes.h"
  29 #include "../libcli/auth/spnego.h"
  30 #include "smb_krb5.h"
  31 #include <keyutils.h>
  32 #include <getopt.h>
  33
  34 #include "cifs_spnego.h"
  35
  36 #define CIFS_DEFAULT_KRB5_DIR           "/tmp"
  37 #define CIFS_DEFAULT_KRB5_PREFIX        "krb5cc_"
  38
  39 #define MAX_CCNAME_LEN                  PATH_MAX + 5
  40
  41 const char *CIFSSPNEGO_VERSION = "1.3";
  42 static const char *prog = "cifs.upcall";
  43 typedef enum _sectype {
  44         NONE = 0,
  45         KRB5,
  46         MS_KRB5
  47 } sectype_t;
  48
  49 /* does the ccache have a valid TGT? */
  50 static time_t
  51 get_tgt_time(const char *ccname) {
  52         krb5_context context;
  53         krb5_ccache ccache;
  54         krb5_cc_cursor cur;
  55         krb5_creds creds;
  56         krb5_principal principal;
  57         time_t credtime = 0;
  58         char *realm = NULL;
  59
  60         if (krb5_init_context(&context)) {
  61                 syslog(LOG_DEBUG, "%s: unable to init krb5 context", __func__);
  62                 return 0;
  63         }
  64
  65         if (krb5_cc_resolve(context, ccname, &ccache)) {
  66                 syslog(LOG_DEBUG, "%s: unable to resolve krb5 cache", __func__);
  67                 goto err_cache;
  68         }
  69
  70         if (krb5_cc_set_flags(context, ccache, 0)) {
  71                 syslog(LOG_DEBUG, "%s: unable to set flags", __func__);
  72                 goto err_cache;
  73         }
  74
  75         if (krb5_cc_get_principal(context, ccache, &principal)) {
  76                 syslog(LOG_DEBUG, "%s: unable to get principal", __func__);
  77                 goto err_princ;
  78         }
  79
  80         if (krb5_cc_start_seq_get(context, ccache, &cur)) {
  81                 syslog(LOG_DEBUG, "%s: unable to seq start", __func__);
  82                 goto err_ccstart;
  83         }
  84
  85         if ((realm = smb_krb5_principal_get_realm(context, principal)) == NULL) {
  86                 syslog(LOG_DEBUG, "%s: unable to get realm", __func__);
  87                 goto err_ccstart;
  88         }
  89
  90         while (!credtime && !krb5_cc_next_cred(context, ccache, &cur, &creds)) {
  91                 char *name;
  92                 if (smb_krb5_unparse_name(NULL, context, creds.server, &name)) {
  93                         syslog(LOG_DEBUG, "%s: unable to unparse name", __func__);
  94                         goto err_endseq;
  95                 }
  96                 if (krb5_realm_compare(context, creds.server, principal) &&
  97                     strnequal(name, KRB5_TGS_NAME, KRB5_TGS_NAME_SIZE) &&
  98                     strnequal(name+KRB5_TGS_NAME_SIZE+1, realm, strlen(realm)) &&
  99                     creds.times.endtime > time(NULL))
 100                         credtime = creds.times.endtime;
 101                 krb5_free_cred_contents(context, &creds);
 102                 TALLOC_FREE(name);
 103         }
 104 err_endseq:
 105         krb5_cc_end_seq_get(context, ccache, &cur);
 106 err_ccstart:
 107         krb5_free_principal(context, principal);
 108 err_princ:
 109 #if defined(KRB5_TC_OPENCLOSE)
 110         krb5_cc_set_flags(context, ccache, KRB5_TC_OPENCLOSE);
 111 #endif
 112         krb5_cc_close(context, ccache);
 113 err_cache:
 114         krb5_free_context(context);
 115         return credtime;
 116 }
 117
 118 static int
 119 krb5cc_filter(const struct dirent *dirent)
 120 {
 121         if (strstr(dirent->d_name, CIFS_DEFAULT_KRB5_PREFIX))
 122                 return 1;
 123         else
 124                 return 0;
 125 }
 126
 127 /* search for a credcache that looks like a likely candidate */
 128 static char *
 129 find_krb5_cc(const char *dirname, uid_t uid)
 130 {
 131         struct dirent **namelist;
 132         struct stat sbuf;
 133         char ccname[MAX_CCNAME_LEN], *credpath, *best_cache = NULL;
 134         int i, n;
 135         time_t cred_time, best_time = 0;
 136
 137         n = scandir(dirname, &namelist, krb5cc_filter, NULL);
 138         if (n < 0) {
 139                 syslog(LOG_DEBUG, "%s: scandir error on directory '%s': %s",
 140                                   __func__, dirname, strerror(errno));
 141                 return NULL;
 142         }
 143
 144         for (i = 0; i < n; i++) {
 145                 snprintf(ccname, sizeof(ccname), "FILE:%s/%s", dirname,
 146                          namelist[i]->d_name);
 147                 credpath = ccname + 5;
 148                 syslog(LOG_DEBUG, "%s: considering %s", __func__, credpath);
 149
 150                 if (lstat(credpath, &sbuf)) {
 151                         syslog(LOG_DEBUG, "%s: stat error on '%s': %s",
 152                                           __func__, credpath, strerror(errno));
 153                         free(namelist[i]);
 154                         continue;
 155                 }
 156                 if (sbuf.st_uid != uid) {
 157                         syslog(LOG_DEBUG, "%s: %s is owned by %u, not %u",
 158                                         __func__, credpath, sbuf.st_uid, uid);
 159                         free(namelist[i]);
 160                         continue;
 161                 }
 162                 if (!S_ISREG(sbuf.st_mode)) {
 163                         syslog(LOG_DEBUG, "%s: %s is not a regular file",
 164                                         __func__, credpath);
 165                         free(namelist[i]);
 166                         continue;
 167                 }
 168                 if (!(cred_time = get_tgt_time(ccname))) {
 169                         syslog(LOG_DEBUG, "%s: %s is not a valid credcache.",
 170                                         __func__, ccname);
 171                         free(namelist[i]);
 172                         continue;
 173                 }
 174
 175                 if (cred_time <= best_time) {
 176                         syslog(LOG_DEBUG, "%s: %s expires sooner than current "
 177                                           "best.", __func__, ccname);
 178                         free(namelist[i]);
 179                         continue;
 180                 }
 181
 182                 syslog(LOG_DEBUG, "%s: %s is valid ccache", __func__, ccname);
 183                 free(best_cache);
 184                 best_cache = SMB_STRNDUP(ccname, MAX_CCNAME_LEN);
 185                 best_time = cred_time;
 186                 free(namelist[i]);
 187         }
 188         free(namelist);
 189
 190         return best_cache;
 191 }
 192
 193 /*
 194  * Prepares AP-REQ data for mechToken and gets session key
 195  * Uses credentials from cache. It will not ask for password
 196  * you should receive credentials for yuor name manually using
 197  * kinit or whatever you wish.
 198  *
 199  * in:
 200  *      oid -           string with OID/ Could be OID_KERBEROS5
 201  *                      or OID_KERBEROS5_OLD
 202  *      principal -     Service name.
 203  *                      Could be "cifs/FQDN" for KRB5 OID
 204  *                      or for MS_KRB5 OID style server principal
 205  *                      like "pdc$@YOUR.REALM.NAME"
 206  *
 207  * out:
 208  *      secblob -       pointer for spnego wrapped AP-REQ data to be stored
 209  *      sess_key-       pointer for SessionKey data to be stored
 210  *
 211  * ret: 0 - success, others - failure
 212  */
 213 static int
 214 handle_krb5_mech(const char *oid, const char *principal, DATA_BLOB *secblob,
 215                  DATA_BLOB *sess_key, const char *ccname)
 216 {
 217         int retval;
 218         DATA_BLOB tkt, tkt_wrapped;
 219
 220         syslog(LOG_DEBUG, "%s: getting service ticket for %s", __func__,
 221                           principal);
 222
 223         /* get a kerberos ticket for the service and extract the session key */
 224         retval = cli_krb5_get_ticket(principal, 0, &tkt, sess_key, 0, ccname,
 225                                      NULL, NULL);
 226
 227         if (retval) {
 228                 syslog(LOG_DEBUG, "%s: failed to obtain service ticket (%d)",
 229                                   __func__, retval);
 230                 return retval;
 231         }
 232
 233         syslog(LOG_DEBUG, "%s: obtained service ticket", __func__);
 234
 235         /* wrap that up in a nice GSS-API wrapping */
 236         tkt_wrapped = spnego_gen_krb5_wrap(tkt, TOK_ID_KRB_AP_REQ);
 237
 238         /* and wrap that in a shiny SPNEGO wrapper */
 239         *secblob = gen_negTokenInit(oid, tkt_wrapped);
 240
 241         data_blob_free(&tkt_wrapped);
 242         data_blob_free(&tkt);
 243         return retval;
 244 }
 245
 246 #define DKD_HAVE_HOSTNAME       0x1
 247 #define DKD_HAVE_VERSION        0x2
 248 #define DKD_HAVE_SEC            0x4
 249 #define DKD_HAVE_IP             0x8
 250 #define DKD_HAVE_UID            0x10
 251 #define DKD_HAVE_PID            0x20
 252 #define DKD_MUSTHAVE_SET (DKD_HAVE_HOSTNAME|DKD_HAVE_VERSION|DKD_HAVE_SEC)
 253
 254 struct decoded_args {
 255         int             ver;
 256         char            *hostname;
 257         char            *ip;
 258         uid_t           uid;
 259         pid_t           pid;
 260         sectype_t       sec;
 261 };
 262
 263 static unsigned int
 264 decode_key_description(const char *desc, struct decoded_args *arg)
 265 {
 266         int len;
 267         int retval = 0;
 268         char *pos;
 269         const char *tkn = desc;
 270
 271         do {
 272                 pos = index(tkn, ';');
 273                 if (strncmp(tkn, "host=", 5) == 0) {
 274
 275                         if (pos == NULL)
 276                                 len = strlen(tkn);
 277                         else
 278                                 len = pos - tkn;
 279
 280                         len -= 4;
 281                         SAFE_FREE(arg->hostname);
 282                         arg->hostname = SMB_XMALLOC_ARRAY(char, len);
 283                         strlcpy(arg->hostname, tkn + 5, len);
 284                         retval |= DKD_HAVE_HOSTNAME;
 285                 } else if (!strncmp(tkn, "ip4=", 4) ||
 286                            !strncmp(tkn, "ip6=", 4)) {
 287                         if (pos == NULL)
 288                                 len = strlen(tkn);
 289                         else
 290                                 len = pos - tkn;
 291
 292                         len -= 3;
 293                         SAFE_FREE(arg->ip);
 294                         arg->ip = SMB_XMALLOC_ARRAY(char, len);
 295                         strlcpy(arg->ip, tkn + 4, len);
 296                         retval |= DKD_HAVE_IP;
 297                 } else if (strncmp(tkn, "pid=", 4) == 0) {
 298                         errno = 0;
 299                         arg->pid = strtol(tkn + 4, NULL, 0);
 300                         if (errno != 0) {
 301                                 syslog(LOG_ERR, "Invalid pid format: %s",
 302                                        strerror(errno));
 303                                 return 1;
 304                         } else {
 305                                 retval |= DKD_HAVE_PID;
 306                         }
 307                 } else if (strncmp(tkn, "sec=", 4) == 0) {
 308                         if (strncmp(tkn + 4, "krb5", 4) == 0) {
 309                                 retval |= DKD_HAVE_SEC;
 310                                 arg->sec = KRB5;
 311                         } else if (strncmp(tkn + 4, "mskrb5", 6) == 0) {
 312                                 retval |= DKD_HAVE_SEC;
 313                                 arg->sec = MS_KRB5;
 314                         }
 315                 } else if (strncmp(tkn, "uid=", 4) == 0) {
 316                         errno = 0;
 317                         arg->uid = strtol(tkn + 4, NULL, 16);
 318                         if (errno != 0) {
 319                                 syslog(LOG_ERR, "Invalid uid format: %s",
 320                                        strerror(errno));
 321                                 return 1;
 322                         } else {
 323                                 retval |= DKD_HAVE_UID;
 324                         }
 325                 } else if (strncmp(tkn, "ver=", 4) == 0) {      /* if version */
 326                         errno = 0;
 327                         arg->ver = strtol(tkn + 4, NULL, 16);
 328                         if (errno != 0) {
 329                                 syslog(LOG_ERR, "Invalid version format: %s",
 330                                        strerror(errno));
 331                                 return 1;
 332                         } else {
 333                                 retval |= DKD_HAVE_VERSION;
 334                         }
 335                 }
 336                 if (pos == NULL)
 337                         break;
 338                 tkn = pos + 1;
 339         } while (tkn);
 340         return retval;
 341 }
 342
 343 static int
 344 cifs_resolver(const key_serial_t key, const char *key_descr)
 345 {
 346         int c;
 347         struct addrinfo *addr;
 348         char ip[INET6_ADDRSTRLEN];
 349         void *p;
 350         const char *keyend = key_descr;
 351         /* skip next 4 ';' delimiters to get to description */
 352         for (c = 1; c <= 4; c++) {
 353                 keyend = index(keyend+1, ';');
 354                 if (!keyend) {
 355                         syslog(LOG_ERR, "invalid key description: %s",
 356                                         key_descr);
 357                         return 1;
 358                 }
 359         }
 360         keyend++;
 361
 362         /* resolve name to ip */
 363         c = getaddrinfo(keyend, NULL, NULL, &addr);
 364         if (c) {
 365                 syslog(LOG_ERR, "unable to resolve hostname: %s [%s]",
 366                                 keyend, gai_strerror(c));
 367                 return 1;
 368         }
 369
 370         /* conver ip to string form */
 371         if (addr->ai_family == AF_INET)
 372                 p = &(((struct sockaddr_in *)addr->ai_addr)->sin_addr);
 373         else
 374                 p = &(((struct sockaddr_in6 *)addr->ai_addr)->sin6_addr);
 375
 376         if (!inet_ntop(addr->ai_family, p, ip, sizeof(ip))) {
 377                 syslog(LOG_ERR, "%s: inet_ntop: %s", __func__, strerror(errno));
 378                 freeaddrinfo(addr);
 379                 return 1;
 380         }
 381
 382         /* setup key */
 383         c = keyctl_instantiate(key, ip, strlen(ip)+1, 0);
 384         if (c == -1) {
 385                 syslog(LOG_ERR, "%s: keyctl_instantiate: %s", __func__,
 386                                 strerror(errno));
 387                 freeaddrinfo(addr);
 388                 return 1;
 389         }
 390
 391         freeaddrinfo(addr);
 392         return 0;
 393 }
 394
 395 /*
 396  * Older kernels sent IPv6 addresses without colons. Well, at least
 397  * they're fixed-length strings. Convert these addresses to have colon
 398  * delimiters to make getaddrinfo happy.
 399  */
 400 static void
 401 convert_inet6_addr(const char *from, char *to)
 402 {
 403         int i = 1;
 404
 405         while (*from) {
 406                 *to++ = *from++;
 407                 if (!(i++ % 4) && *from)
 408                         *to++ = ':';
 409         }
 410         *to = 0;
 411 }
 412
 413 static int
 414 ip_to_fqdn(const char *addrstr, char *host, size_t hostlen)
 415 {
 416         int rc;
 417         struct addrinfo hints = { .ai_flags = AI_NUMERICHOST };
 418         struct addrinfo *res;
 419         const char *ipaddr = addrstr;
 420         char converted[INET6_ADDRSTRLEN + 1];
 421
 422         if ((strlen(ipaddr) > INET_ADDRSTRLEN) && !strchr(ipaddr, ':')) {
 423                 convert_inet6_addr(ipaddr, converted);
 424                 ipaddr = converted;
 425         }
 426
 427         rc = getaddrinfo(ipaddr, NULL, &hints, &res);
 428         if (rc) {
 429                 syslog(LOG_DEBUG, "%s: failed to resolve %s to "
 430                         "ipaddr: %s", __func__, ipaddr,
 431                 rc == EAI_SYSTEM ? strerror(errno) : gai_strerror(rc));
 432                 return rc;
 433         }
 434
 435         rc = getnameinfo(res->ai_addr, res->ai_addrlen, host, hostlen,
 436                          NULL, 0, NI_NAMEREQD);
 437         freeaddrinfo(res);
 438         if (rc) {
 439                 syslog(LOG_DEBUG, "%s: failed to resolve %s to fqdn: %s",
 440                         __func__, ipaddr,
 441                         rc == EAI_SYSTEM ? strerror(errno) : gai_strerror(rc));
 442                 return rc;
 443         }
 444
 445         syslog(LOG_DEBUG, "%s: resolved %s to %s", __func__, ipaddr, host);
 446         return 0;
 447 }
 448
 449 static void
 450 usage(void)
 451 {
 452         syslog(LOG_INFO, "Usage: %s [-t] [-v] key_serial", prog);
 453         fprintf(stderr, "Usage: %s [-t] [-v] key_serial\n", prog);
 454 }
 455
 456 const struct option long_options[] = {
 457         { "trust-dns",  0, NULL, 't' },
 458         { "version",    0, NULL, 'v' },
 459         { NULL,         0, NULL, 0 }
 460 };
 461
 462 int main(const int argc, char *const argv[])
 463 {
 464         struct cifs_spnego_msg *keydata = NULL;
 465         DATA_BLOB secblob = data_blob_null;
 466         DATA_BLOB sess_key = data_blob_null;
 467         key_serial_t key = 0;
 468         size_t datalen;
 469         unsigned int have;
 470         long rc = 1;
 471         int c, try_dns = 0;
 472         char *buf, *princ = NULL, *ccname = NULL;
 473         char hostbuf[NI_MAXHOST], *host;
 474         struct decoded_args arg = { };
 475         const char *oid;
 476
 477         hostbuf[0] = '\0';
 478
 479         openlog(prog, 0, LOG_DAEMON);
 480
 481         while ((c = getopt_long(argc, argv, "ctv", long_options, NULL)) != -1) {
 482                 switch (c) {
 483                 case 'c':
 484                         /* legacy option -- skip it */
 485                         break;
 486                 case 't':
 487                         try_dns++;
 488                         break;
 489                 case 'v':
 490                         printf("version: %s\n", CIFSSPNEGO_VERSION);
 491                         goto out;
 492                 default:
 493                         syslog(LOG_ERR, "unknown option: %c", c);
 494                         goto out;
 495                 }
 496         }
 497
 498         /* is there a key? */
 499         if (argc <= optind) {
 500                 usage();
 501                 goto out;
 502         }
 503
 504         /* get key and keyring values */
 505         errno = 0;
 506         key = strtol(argv[optind], NULL, 10);
 507         if (errno != 0) {
 508                 key = 0;
 509                 syslog(LOG_ERR, "Invalid key format: %s", strerror(errno));
 510                 goto out;
 511         }
 512
 513         rc = keyctl_describe_alloc(key, &buf);
 514         if (rc == -1) {
 515                 syslog(LOG_ERR, "keyctl_describe_alloc failed: %s",
 516                        strerror(errno));
 517                 rc = 1;
 518                 goto out;
 519         }
 520
 521         syslog(LOG_DEBUG, "key description: %s", buf);
 522
 523         if ((strncmp(buf, "cifs.resolver", sizeof("cifs.resolver")-1) == 0) ||
 524             (strncmp(buf, "dns_resolver", sizeof("dns_resolver")-1) == 0)) {
 525                 rc = cifs_resolver(key, buf);
 526                 goto out;
 527         }
 528
 529         have = decode_key_description(buf, &arg);
 530         SAFE_FREE(buf);
 531         if ((have & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) {
 532                 syslog(LOG_ERR, "unable to get necessary params from key "
 533                                 "description (0x%x)", have);
 534                 rc = 1;
 535                 goto out;
 536         }
 537
 538         if (arg.ver > CIFS_SPNEGO_UPCALL_VERSION) {
 539                 syslog(LOG_ERR, "incompatible kernel upcall version: 0x%x",
 540                                 arg.ver);
 541                 rc = 1;
 542                 goto out;
 543         }
 544
 545         if (have & DKD_HAVE_UID) {
 546                 rc = setuid(arg.uid);
 547                 if (rc == -1) {
 548                         syslog(LOG_ERR, "setuid: %s", strerror(errno));
 549                         goto out;
 550                 }
 551
 552                 ccname = find_krb5_cc(CIFS_DEFAULT_KRB5_DIR, arg.uid);
 553         }
 554
 555         host = arg.hostname;
 556
 557         // do mech specific authorization
 558         switch (arg.sec) {
 559         case MS_KRB5:
 560         case KRB5:
 561 retry_new_hostname:
 562                 /* for "cifs/" service name + terminating 0 */
 563                 datalen = strlen(host) + 5 + 1;
 564                 princ = SMB_XMALLOC_ARRAY(char, datalen);
 565                 if (!princ) {
 566                         rc = -ENOMEM;
 567                         break;
 568                 }
 569
 570                 if (arg.sec == MS_KRB5)
 571                         oid = OID_KERBEROS5_OLD;
 572                 else
 573                         oid = OID_KERBEROS5;
 574
 575                 /*
 576                  * try getting a cifs/ principal first and then fall back to
 577                  * getting a host/ principal if that doesn't work.
 578                  */
 579                 strlcpy(princ, "cifs/", datalen);
 580                 strlcpy(princ + 5, host, datalen - 5);
 581                 rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname);
 582                 if (!rc)
 583                         break;
 584
 585                 memcpy(princ, "host/", 5);
 586                 rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname);
 587                 if (!rc)
 588                         break;
 589
 590                 if (!try_dns || !(have & DKD_HAVE_IP))
 591                         break;
 592
 593                 rc = ip_to_fqdn(arg.ip, hostbuf, sizeof(hostbuf));
 594                 if (rc)
 595                         break;
 596
 597                 SAFE_FREE(princ);
 598                 try_dns = 0;
 599                 host = hostbuf;
 600                 goto retry_new_hostname;
 601         default:
 602                 syslog(LOG_ERR, "sectype: %d is not implemented", arg.sec);
 603                 rc = 1;
 604                 break;
 605         }
 606
 607         SAFE_FREE(princ);
 608
 609         if (rc)
 610                 goto out;
 611
 612         /* pack SecurityBLob and SessionKey into downcall packet */
 613         datalen =
 614             sizeof(struct cifs_spnego_msg) + secblob.length + sess_key.length;
 615         keydata = (struct cifs_spnego_msg*)SMB_XMALLOC_ARRAY(char, datalen);
 616         if (!keydata) {
 617                 rc = 1;
 618                 goto out;
 619         }
 620         keydata->version = arg.ver;
 621         keydata->flags = 0;
 622         keydata->sesskey_len = sess_key.length;
 623         keydata->secblob_len = secblob.length;
 624         memcpy(&(keydata->data), sess_key.data, sess_key.length);
 625         memcpy(&(keydata->data) + keydata->sesskey_len,
 626                secblob.data, secblob.length);
 627
 628         /* setup key */
 629         rc = keyctl_instantiate(key, keydata, datalen, 0);
 630         if (rc == -1) {
 631                 syslog(LOG_ERR, "keyctl_instantiate: %s", strerror(errno));
 632                 goto out;
 633         }
 634
 635         /* BB: maybe we need use timeout for key: for example no more then
 636          * ticket lifietime? */
 637         /* keyctl_set_timeout( key, 60); */
 638 out:
 639         /*
 640          * on error, negatively instantiate the key ourselves so that we can
 641          * make sure the kernel doesn't hang it off of a searchable keyring
 642          * and interfere with the next attempt to instantiate the key.
 643          */
 644         if (rc != 0  && key == 0)
 645                 keyctl_negate(key, 1, KEY_REQKEY_DEFL_DEFAULT);
 646         data_blob_free(&secblob);
 647         data_blob_free(&sess_key);
 648         SAFE_FREE(ccname);
 649         SAFE_FREE(arg.hostname);
 650         SAFE_FREE(arg.ip);
 651         SAFE_FREE(keydata);
 652         return rc;
 653 }