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