nsswitch/winbind_krb5_locator.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos locator plugin
   4    Copyright (C) Guenther Deschner 2007-2008
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "nsswitch/winbind_client.h"
  21 #include "libwbclient/wbclient.h"
  22
  23 #ifndef DEBUG_KRB5
  24 #undef DEBUG_KRB5
  25 #endif
  26
  27 #if defined(HAVE_KRB5) && defined(HAVE_KRB5_LOCATE_PLUGIN_H)
  28
  29 #if HAVE_COM_ERR_H
  30 #include <com_err.h>
  31 #endif
  32
  33 #include <krb5.h>
  34 #include <krb5/locate_plugin.h>
  35
  36 #ifndef KRB5_PLUGIN_NO_HANDLE
  37 #define KRB5_PLUGIN_NO_HANDLE KRB5_KDC_UNREACH /* Heimdal */
  38 #endif
  39
  40 static const char *get_service_from_locate_service_type(enum locate_service_type svc)
  41 {
  42         switch (svc) {
  43                 case locate_service_kdc:
  44                 case locate_service_master_kdc:
  45                         return "88";
  46                 case locate_service_kadmin:
  47                 case locate_service_krb524:
  48                         /* not supported */
  49                         return NULL;
  50                 case locate_service_kpasswd:
  51                         return "464";
  52                 default:
  53                         break;
  54         }
  55         return NULL;
  56
  57 }
  58
  59 #ifdef DEBUG_KRB5
  60 static const char *locate_service_type_name(enum locate_service_type svc)
  61 {
  62         switch (svc) {
  63                 case locate_service_kdc:
  64                         return "locate_service_kdc";
  65                 case locate_service_master_kdc:
  66                         return "locate_service_master_kdc";
  67                 case locate_service_kadmin:
  68                         return "locate_service_kadmin";
  69                 case locate_service_krb524:
  70                         return "locate_service_krb524";
  71                 case locate_service_kpasswd:
  72                         return "locate_service_kpasswd";
  73                 default:
  74                         break;
  75         }
  76         return NULL;
  77 }
  78
  79 static const char *socktype_name(int socktype)
  80 {
  81         switch (socktype) {
  82                 case SOCK_STREAM:
  83                         return "SOCK_STREAM";
  84                 case SOCK_DGRAM:
  85                         return "SOCK_DGRAM";
  86                 default:
  87                         break;
  88         }
  89         return "unknown";
  90 }
  91
  92 static const char *family_name(int family)
  93 {
  94         switch (family) {
  95                 case AF_UNSPEC:
  96                         return "AF_UNSPEC";
  97                 case AF_INET:
  98                         return "AF_INET";
  99 #if defined(HAVE_IPV6)
 100                 case AF_INET6:
 101                         return "AF_INET6";
 102 #endif
 103                 default:
 104                         break;
 105         }
 106         return "unknown";
 107 }
 108 #endif
 109
 110 /**
 111  * Check input parameters, return KRB5_PLUGIN_NO_HANDLE for unsupported ones
 112  *
 113  * @param svc
 114  * @param realm string
 115  * @param socktype integer
 116  * @param family integer
 117  *
 118  * @return integer.
 119  */
 120
 121 static int smb_krb5_locator_lookup_sanity_check(enum locate_service_type svc,
 122                                                 const char *realm,
 123                                                 int socktype,
 124                                                 int family)
 125 {
 126         if (!realm || strlen(realm) == 0) {
 127                 return EINVAL;
 128         }
 129
 130         switch (svc) {
 131                 case locate_service_kdc:
 132                 case locate_service_master_kdc:
 133                 case locate_service_kpasswd:
 134                         break;
 135                 case locate_service_kadmin:
 136                 case locate_service_krb524:
 137                         return KRB5_PLUGIN_NO_HANDLE;
 138                 default:
 139                         return EINVAL;
 140         }
 141
 142         switch (family) {
 143                 case AF_UNSPEC:
 144                 case AF_INET:
 145                         break;
 146 #if defined(HAVE_IPV6)
 147                 case AF_INET6:
 148                         break;
 149 #endif
 150                 default:
 151                         return EINVAL;
 152         }
 153
 154         switch (socktype) {
 155                 case SOCK_STREAM:
 156                 case SOCK_DGRAM:
 157                 case 0: /* Heimdal uses that */
 158                         break;
 159                 default:
 160                         return EINVAL;
 161         }
 162
 163         return 0;
 164 }
 165
 166 /**
 167  * Try to get addrinfo for a given host and call the krb5 callback
 168  *
 169  * @param name string
 170  * @param service string
 171  * @param in struct addrinfo hint
 172  * @param cbfunc krb5 callback function
 173  * @param cbdata void pointer cbdata
 174  *
 175  * @return krb5_error_code.
 176  */
 177
 178 static krb5_error_code smb_krb5_locator_call_cbfunc(const char *name,
 179                                                     const char *service,
 180                                                     struct addrinfo *in,
 181                                                     int (*cbfunc)(void *, int, struct sockaddr *),
 182                                                     void *cbdata)
 183 {
 184         struct addrinfo *out = NULL;
 185         int ret = 0;
 186         struct addrinfo *res = NULL;
 187         int count = 3;
 188
 189         while (count) {
 190
 191                 ret = getaddrinfo(name, service, in, &out);
 192                 if (ret == 0) {
 193                         break;
 194                 }
 195
 196                 if ((ret == EAI_AGAIN) && (count > 1)) {
 197                         count--;
 198                         continue;
 199                 }
 200
 201 #ifdef DEBUG_KRB5
 202                 fprintf(stderr, "[%5u]: smb_krb5_locator_lookup: "
 203                         "getaddrinfo failed: %s (%d)\n",
 204                         (unsigned int)getpid(), gai_strerror(ret), ret);
 205 #endif
 206
 207                 return KRB5_PLUGIN_NO_HANDLE;
 208         }
 209
 210         for (res = out; res; res = res->ai_next) {
 211                 if (!res->ai_addr || res->ai_addrlen == 0) {
 212                         continue;
 213                 }
 214
 215                 ret = cbfunc(cbdata, res->ai_socktype, res->ai_addr);
 216                 if (ret) {
 217 #ifdef DEBUG_KRB5
 218                         fprintf(stderr, "[%5u]: smb_krb5_locator_lookup: "
 219                                 "failed to call callback: %s (%d)\n",
 220                                 (unsigned int)getpid(), error_message(ret), ret);
 221 #endif
 222                         break;
 223                 }
 224         }
 225
 226         if (out) {
 227                 freeaddrinfo(out);
 228         }
 229         return ret;
 230 }
 231
 232 /**
 233  * PUBLIC INTERFACE: locate init
 234  *
 235  * @param context krb5_context
 236  * @param privata_data pointer to private data pointer
 237  *
 238  * @return krb5_error_code.
 239  */
 240
 241 static krb5_error_code smb_krb5_locator_init(krb5_context context,
 242                                              void **private_data)
 243 {
 244         return 0;
 245 }
 246
 247 /**
 248  * PUBLIC INTERFACE: close locate
 249  *
 250  * @param private_data pointer to private data
 251  *
 252  * @return void.
 253  */
 254
 255 static void smb_krb5_locator_close(void *private_data)
 256 {
 257         return;
 258 }
 259
 260
 261 static bool ask_winbind(const char *realm, char **dcname)
 262 {
 263         wbcErr wbc_status;
 264         const char *dc = NULL;
 265         struct wbcDomainControllerInfoEx *dc_info = NULL;
 266         uint32_t flags;
 267
 268         flags = WBC_LOOKUP_DC_KDC_REQUIRED |
 269                 WBC_LOOKUP_DC_IS_DNS_NAME |
 270                 WBC_LOOKUP_DC_RETURN_DNS_NAME;
 271
 272         wbc_status = wbcLookupDomainControllerEx(realm, NULL, NULL, flags, &dc_info);
 273
 274         if (!WBC_ERROR_IS_OK(wbc_status)) {
 275 #ifdef DEBUG_KRB5
 276                 fprintf(stderr,"[%5u]: smb_krb5_locator_lookup: failed with: %s\n",
 277                         (unsigned int)getpid(), wbcErrorString(wbc_status));
 278 #endif
 279                 return false;
 280         }
 281
 282         if (!dc && dc_info->dc_unc) {
 283                 dc = dc_info->dc_unc;
 284                 if (dc[0] == '\\') dc++;
 285                 if (dc[0] == '\\') dc++;
 286         }
 287
 288         if (!dc) {
 289                 wbcFreeMemory(dc_info);
 290                 return false;
 291         }
 292
 293         *dcname = strdup(dc);
 294         if (!*dcname) {
 295                 wbcFreeMemory(dc_info);
 296                 return false;
 297         }
 298
 299         wbcFreeMemory(dc_info);
 300         return true;
 301 }
 302
 303 /**
 304  * PUBLIC INTERFACE: locate lookup
 305  *
 306  * @param private_data pointer to private data
 307  * @param svc enum locate_service_type.
 308  * @param realm string
 309  * @param socktype integer
 310  * @param family integer
 311  * @param cbfunc callback function to send back entries
 312  * @param cbdata void pointer to cbdata
 313  *
 314  * @return krb5_error_code.
 315  */
 316
 317 static krb5_error_code smb_krb5_locator_lookup(void *private_data,
 318                                                enum locate_service_type svc,
 319                                                const char *realm,
 320                                                int socktype,
 321                                                int family,
 322                                                int (*cbfunc)(void *, int, struct sockaddr *),
 323                                                         void *cbdata)
 324 {
 325         krb5_error_code ret;
 326         struct addrinfo aihints;
 327         char *kdc_name = NULL;
 328         const char *service = get_service_from_locate_service_type(svc);
 329
 330         ZERO_STRUCT(aihints);
 331
 332 #ifdef DEBUG_KRB5
 333         fprintf(stderr,"[%5u]: smb_krb5_locator_lookup: called for '%s' "
 334                         "svc: '%s' (%d) "
 335                         "socktype: '%s' (%d), family: '%s' (%d)\n",
 336                         (unsigned int)getpid(), realm,
 337                         locate_service_type_name(svc), svc,
 338                         socktype_name(socktype), socktype,
 339                         family_name(family), family);
 340 #endif
 341         ret = smb_krb5_locator_lookup_sanity_check(svc, realm, socktype,
 342                                                    family);
 343         if (ret) {
 344 #ifdef DEBUG_KRB5
 345                 fprintf(stderr, "[%5u]: smb_krb5_locator_lookup: "
 346                         "returning ret: %s (%d)\n",
 347                         (unsigned int)getpid(), error_message(ret), ret);
 348 #endif
 349                 return ret;
 350         }
 351
 352         if (!winbind_env_set()) {
 353                 if (!ask_winbind(realm, &kdc_name)) {
 354 #ifdef DEBUG_KRB5
 355                         fprintf(stderr, "[%5u]: smb_krb5_locator_lookup: "
 356                                 "failed to query winbindd\n",
 357                                 (unsigned int)getpid());
 358 #endif
 359                         goto failed;
 360                 }
 361         } else {
 362                 const char *env = NULL;
 363                 char *var = NULL;
 364                 if (asprintf(&var, "%s_%s",
 365                              WINBINDD_LOCATOR_KDC_ADDRESS, realm) == -1) {
 366                         goto failed;
 367                 }
 368                 env = getenv(var);
 369                 if (!env) {
 370 #ifdef DEBUG_KRB5
 371                         fprintf(stderr, "[%5u]: smb_krb5_locator_lookup: "
 372                                 "failed to get kdc from env %s\n",
 373                                 (unsigned int)getpid(), var);
 374 #endif
 375                         free(var);
 376                         goto failed;
 377                 }
 378                 free(var);
 379
 380                 kdc_name = strdup(env);
 381                 if (!kdc_name) {
 382                         goto failed;
 383                 }
 384         }
 385 #ifdef DEBUG_KRB5
 386         fprintf(stderr, "[%5u]: smb_krb5_locator_lookup: "
 387                 "got '%s' for '%s' from winbindd\n", (unsigned int)getpid(),
 388                 kdc_name, realm);
 389 #endif
 390
 391         aihints.ai_family = family;
 392         aihints.ai_socktype = socktype;
 393
 394         ret = smb_krb5_locator_call_cbfunc(kdc_name,
 395                                            service,
 396                                            &aihints,
 397                                            cbfunc, cbdata);
 398         SAFE_FREE(kdc_name);
 399
 400         return ret;
 401
 402  failed:
 403         return KRB5_PLUGIN_NO_HANDLE;
 404 }
 405
 406 #ifdef HEIMDAL_KRB5_LOCATE_PLUGIN_H
 407 #define SMB_KRB5_LOCATOR_SYMBOL_NAME resolve /* Heimdal */
 408 #else
 409 #define SMB_KRB5_LOCATOR_SYMBOL_NAME service_locator /* MIT */
 410 #endif
 411
 412 const krb5plugin_service_locate_ftable SMB_KRB5_LOCATOR_SYMBOL_NAME = {
 413         0, /* version */
 414         smb_krb5_locator_init,
 415         smb_krb5_locator_close,
 416         smb_krb5_locator_lookup,
 417 };
 418
 419 #endif