source3/lib/idmap_cache.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    ID Mapping Cache
   4
   5    Copyright (C) Volker Lendecke        2008
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.*/
  19
  20 #include "includes.h"
  21 #include "idmap_cache.h"
  22 #include "../libcli/security/security.h"
  23 #include "../librpc/gen_ndr/idmap.h"
  24 #include "lib/gencache.h"
  25 #include "lib/util/string_wrappers.h"
  26
  27 /**
  28  * Find a sid2xid mapping
  29  * @param[in] sid               the sid to map
  30  * @param[out] id               where to put the result
  31  * @param[out] expired          is the cache entry expired?
  32  * @retval Was anything in the cache at all?
  33  *
  34  * If id->id == -1 this was a negative mapping.
  35  */
  36
  37 bool idmap_cache_find_sid2unixid(const struct dom_sid *sid, struct unixid *id,
  38                                  bool *expired)
  39 {
  40         struct dom_sid_buf sidstr;
  41         char *key;
  42         char *value = NULL;
  43         char *endptr;
  44         time_t timeout;
  45         bool ret;
  46         struct unixid tmp_id;
  47
  48         key = talloc_asprintf(talloc_tos(), "IDMAP/SID2XID/%s",
  49                               dom_sid_str_buf(sid, &sidstr));
  50         if (key == NULL) {
  51                 return false;
  52         }
  53         ret = gencache_get(key, talloc_tos(), &value, &timeout);
  54         if (!ret) {
  55                 goto done;
  56         }
  57
  58         DEBUG(10, ("Parsing value for key [%s]: value=[%s]\n", key, value));
  59
  60         if (value[0] == '\0') {
  61                 DEBUG(0, ("Failed to parse value for key [%s]: "
  62                           "value is empty\n", key));
  63                 ret = false;
  64                 goto done;
  65         }
  66
  67         tmp_id.id = strtol(value, &endptr, 10);
  68
  69         if ((value == endptr) && (tmp_id.id == 0)) {
  70                 DEBUG(0, ("Failed to parse value for key [%s]: value[%s] does "
  71                           "not start with a number\n", key, value));
  72                 ret = false;
  73                 goto done;
  74         }
  75
  76         DEBUG(10, ("Parsing value for key [%s]: id=[%llu], endptr=[%s]\n",
  77                    key, (unsigned long long)tmp_id.id, endptr));
  78
  79         ret = (*endptr == ':');
  80         if (ret) {
  81                 switch (endptr[1]) {
  82                 case 'U':
  83                         tmp_id.type = ID_TYPE_UID;
  84                         break;
  85
  86                 case 'G':
  87                         tmp_id.type = ID_TYPE_GID;
  88                         break;
  89
  90                 case 'B':
  91                         tmp_id.type = ID_TYPE_BOTH;
  92                         break;
  93
  94                 case 'N':
  95                         tmp_id.type = ID_TYPE_NOT_SPECIFIED;
  96                         break;
  97
  98                 case '\0':
  99                         DEBUG(0, ("FAILED to parse value for key [%s] "
 100                                   "(id=[%llu], endptr=[%s]): "
 101                                   "no type character after colon\n",
 102                                   key, (unsigned long long)tmp_id.id, endptr));
 103                         ret = false;
 104                         goto done;
 105                 default:
 106                         DEBUG(0, ("FAILED to parse value for key [%s] "
 107                                   "(id=[%llu], endptr=[%s]): "
 108                                   "illegal type character '%c'\n",
 109                                   key, (unsigned long long)tmp_id.id, endptr,
 110                                   endptr[1]));
 111                         ret = false;
 112                         goto done;
 113                 }
 114                 if (endptr[2] != '\0') {
 115                         DEBUG(0, ("FAILED to parse value for key [%s] "
 116                                   "(id=[%llu], endptr=[%s]): "
 117                                   "more than 1 type character after colon\n",
 118                                   key, (unsigned long long)tmp_id.id, endptr));
 119                         ret = false;
 120                         goto done;
 121                 }
 122
 123                 *id = tmp_id;
 124                 *expired = (timeout <= time(NULL));
 125         } else {
 126                 DEBUG(0, ("FAILED to parse value for key [%s] (value=[%s]): "
 127                           "colon missing after id=[%llu]\n",
 128                           key, value, (unsigned long long)tmp_id.id));
 129         }
 130
 131 done:
 132         TALLOC_FREE(key);
 133         TALLOC_FREE(value);
 134         return ret;
 135 }
 136
 137 /**
 138  * Find a sid2uid mapping
 139  * @param[in] sid               the sid to map
 140  * @param[out] puid             where to put the result
 141  * @param[out] expired          is the cache entry expired?
 142  * @retval Was anything in the cache at all?
 143  *
 144  * If *puid == -1 this was a negative mapping.
 145  */
 146
 147 bool idmap_cache_find_sid2uid(const struct dom_sid *sid, uid_t *puid,
 148                               bool *expired)
 149 {
 150         bool ret;
 151         struct unixid id;
 152         ret = idmap_cache_find_sid2unixid(sid, &id, expired);
 153         if (!ret) {
 154                 return false;
 155         }
 156
 157         if (id.type == ID_TYPE_BOTH || id.type == ID_TYPE_UID) {
 158                 *puid = id.id;
 159         } else {
 160                 *puid = -1;
 161         }
 162         return true;
 163 }
 164
 165 /**
 166  * Find a sid2gid mapping
 167  * @param[in] sid               the sid to map
 168  * @param[out] pgid             where to put the result
 169  * @param[out] expired          is the cache entry expired?
 170  * @retval Was anything in the cache at all?
 171  *
 172  * If *pgid == -1 this was a negative mapping.
 173  */
 174
 175 bool idmap_cache_find_sid2gid(const struct dom_sid *sid, gid_t *pgid,
 176                               bool *expired)
 177 {
 178         bool ret;
 179         struct unixid id;
 180         ret = idmap_cache_find_sid2unixid(sid, &id, expired);
 181         if (!ret) {
 182                 return false;
 183         }
 184
 185         if (id.type == ID_TYPE_BOTH || id.type == ID_TYPE_GID) {
 186                 *pgid = id.id;
 187         } else {
 188                 *pgid = -1;
 189         }
 190         return true;
 191 }
 192
 193 struct idmap_cache_xid2sid_state {
 194         struct dom_sid *sid;
 195         bool *expired;
 196         bool ret;
 197 };
 198
 199 static void idmap_cache_xid2sid_parser(const struct gencache_timeout *timeout,
 200                                        DATA_BLOB blob,
 201                                        void *private_data)
 202 {
 203         struct idmap_cache_xid2sid_state *state =
 204                 (struct idmap_cache_xid2sid_state *)private_data;
 205         char *value;
 206
 207         if ((blob.length == 0) || (blob.data[blob.length-1] != 0)) {
 208                 /*
 209                  * Not a string, can't be a valid mapping
 210                  */
 211                 state->ret = false;
 212                 return;
 213         }
 214
 215         value = (char *)blob.data;
 216
 217         if ((value[0] == '-') && (value[1] == '\0')) {
 218                 /*
 219                  * Return NULL SID, see comment to uid2sid
 220                  */
 221                 *state->sid = (struct dom_sid) {0};
 222                 state->ret = true;
 223         } else {
 224                 state->ret = string_to_sid(state->sid, value);
 225         }
 226         if (state->ret) {
 227                 *state->expired = gencache_timeout_expired(timeout);
 228         }
 229 }
 230
 231 /**
 232  * Find a xid2sid mapping
 233  * @param[in] id                the unix id to map
 234  * @param[out] sid              where to put the result
 235  * @param[out] expired          is the cache entry expired?
 236  * @retval Was anything in the cache at all?
 237  *
 238  * If "is_null_sid(sid)", this was a negative mapping.
 239  */
 240 bool idmap_cache_find_xid2sid(
 241         const struct unixid *id, struct dom_sid *sid, bool *expired)
 242 {
 243         struct idmap_cache_xid2sid_state state = {
 244                 .sid = sid, .expired = expired
 245         };
 246         fstring key;
 247         char c;
 248
 249         switch (id->type) {
 250         case ID_TYPE_UID:
 251                 c = 'U';
 252                 break;
 253         case ID_TYPE_GID:
 254                 c = 'G';
 255                 break;
 256         default:
 257                 return false;
 258         }
 259
 260         fstr_sprintf(key, "IDMAP/%cID2SID/%d", c, (int)id->id);
 261
 262         gencache_parse(key, idmap_cache_xid2sid_parser, &state);
 263         return state.ret;
 264 }
 265
 266
 267 /**
 268  * Store a mapping in the idmap cache
 269  * @param[in] sid               the sid to map
 270  * @param[in] unix_id           the unix_id to map
 271  *
 272  * If both parameters are valid values, then a positive mapping in both
 273  * directions is stored. If "is_null_sid(sid)" is true, then this will be a
 274  * negative mapping of xid, we want to cache that for this xid we could not
 275  * find anything. Likewise if "xid==-1", then we want to cache that we did not
 276  * find a mapping for the sid passed here.
 277  */
 278
 279 void idmap_cache_set_sid2unixid(const struct dom_sid *sid, struct unixid *unix_id)
 280 {
 281         time_t now = time(NULL);
 282         time_t timeout;
 283         fstring key, value;
 284
 285         if (!is_null_sid(sid)) {
 286                 struct dom_sid_buf sidstr;
 287                 fstr_sprintf(key, "IDMAP/SID2XID/%s",
 288                              dom_sid_str_buf(sid, &sidstr));
 289                 switch (unix_id->type) {
 290                 case ID_TYPE_UID:
 291                         fstr_sprintf(value, "%d:U", (int)unix_id->id);
 292                         break;
 293                 case ID_TYPE_GID:
 294                         fstr_sprintf(value, "%d:G", (int)unix_id->id);
 295                         break;
 296                 case ID_TYPE_BOTH:
 297                         fstr_sprintf(value, "%d:B", (int)unix_id->id);
 298                         break;
 299                 case ID_TYPE_NOT_SPECIFIED:
 300                         fstr_sprintf(value, "%d:N", (int)unix_id->id);
 301                         break;
 302                 default:
 303                         return;
 304                 }
 305                 timeout = (unix_id->id == -1)
 306                         ? lp_idmap_negative_cache_time()
 307                         : lp_idmap_cache_time();
 308                 gencache_set(key, value, now + timeout);
 309         }
 310         if (unix_id->id != -1) {
 311                 if (is_null_sid(sid)) {
 312                         /* negative xid mapping */
 313                         fstrcpy(value, "-");
 314                         timeout = lp_idmap_negative_cache_time();
 315                 }
 316                 else {
 317                         sid_to_fstring(value, sid);
 318                         timeout = lp_idmap_cache_time();
 319                 }
 320                 switch (unix_id->type) {
 321                 case ID_TYPE_BOTH:
 322                         fstr_sprintf(key, "IDMAP/UID2SID/%d", (int)unix_id->id);
 323                         gencache_set(key, value, now + timeout);
 324                         fstr_sprintf(key, "IDMAP/GID2SID/%d", (int)unix_id->id);
 325                         gencache_set(key, value, now + timeout);
 326                         return;
 327
 328                 case ID_TYPE_UID:
 329                         fstr_sprintf(key, "IDMAP/UID2SID/%d", (int)unix_id->id);
 330                         break;
 331
 332                 case ID_TYPE_GID:
 333                         fstr_sprintf(key, "IDMAP/GID2SID/%d", (int)unix_id->id);
 334                         break;
 335
 336                 default:
 337                         return;
 338                 }
 339                 gencache_set(key, value, now + timeout);
 340         }
 341 }
 342
 343 static char* key_xid2sid_str(TALLOC_CTX* mem_ctx, char t, const char* id) {
 344         return talloc_asprintf(mem_ctx, "IDMAP/%cID2SID/%s", t, id);
 345 }
 346
 347 static char* key_xid2sid(TALLOC_CTX* mem_ctx, char t, int id) {
 348         char str[32];
 349         snprintf(str, sizeof(str), "%d", id);
 350         return key_xid2sid_str(mem_ctx, t, str);
 351 }
 352
 353 static char* key_sid2xid_str(TALLOC_CTX* mem_ctx, const char* id) {
 354         return talloc_asprintf(mem_ctx, "IDMAP/SID2XID/%s", id);
 355 }
 356
 357 static bool idmap_cache_del_xid(char t, int xid)
 358 {
 359         TALLOC_CTX* mem_ctx = talloc_stackframe();
 360         const char* key = key_xid2sid(mem_ctx, t, xid);
 361         char* sid_str = NULL;
 362         time_t timeout;
 363         bool ret = true;
 364
 365         if (!gencache_get(key, mem_ctx, &sid_str, &timeout)) {
 366                 DEBUG(3, ("no entry: %s\n", key));
 367                 ret = false;
 368                 goto done;
 369         }
 370
 371         if (sid_str[0] != '-') {
 372                 const char* sid_key = key_sid2xid_str(mem_ctx, sid_str);
 373                 if (!gencache_del(sid_key)) {
 374                         DEBUG(2, ("failed to delete: %s\n", sid_key));
 375                         ret = false;
 376                 } else {
 377                         DEBUG(5, ("delete: %s\n", sid_key));
 378                 }
 379
 380         }
 381
 382         if (!gencache_del(key)) {
 383                 DEBUG(1, ("failed to delete: %s\n", key));
 384                 ret = false;
 385         } else {
 386                 DEBUG(5, ("delete: %s\n", key));
 387         }
 388
 389 done:
 390         talloc_free(mem_ctx);
 391         return ret;
 392 }
 393
 394 bool idmap_cache_del_uid(uid_t uid) {
 395         return idmap_cache_del_xid('U', uid);
 396 }
 397
 398 bool idmap_cache_del_gid(gid_t gid) {
 399         return idmap_cache_del_xid('G', gid);
 400 }
 401
 402 bool idmap_cache_del_sid(const struct dom_sid *sid)
 403 {
 404         TALLOC_CTX* mem_ctx = talloc_stackframe();
 405         bool ret = true;
 406         bool expired;
 407         struct unixid id;
 408         struct dom_sid_buf sidbuf;
 409         const char *sid_key;
 410
 411         if (!idmap_cache_find_sid2unixid(sid, &id, &expired)) {
 412                 ret = false;
 413                 goto done;
 414         }
 415
 416         if (id.id != -1) {
 417                 switch (id.type) {
 418                 case ID_TYPE_BOTH:
 419                         idmap_cache_del_xid('U', id.id);
 420                         idmap_cache_del_xid('G', id.id);
 421                         break;
 422                 case ID_TYPE_UID:
 423                         idmap_cache_del_xid('U', id.id);
 424                         break;
 425                 case ID_TYPE_GID:
 426                         idmap_cache_del_xid('G', id.id);
 427                         break;
 428                 default:
 429                         break;
 430                 }
 431         }
 432
 433         sid_key = key_sid2xid_str(mem_ctx, dom_sid_str_buf(sid, &sidbuf));
 434         if (sid_key == NULL) {
 435                 return false;
 436         }
 437         /* If the mapping was symmetric, then this should fail */
 438         gencache_del(sid_key);
 439 done:
 440         talloc_free(mem_ctx);
 441         return ret;
 442 }