lib/hdb/hdb.c

   1 /*
   2  * Copyright (c) 1997 - 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 "hdb_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 #ifdef HAVE_DLFCN_H
  39 #include <dlfcn.h>
  40 #endif
  41
  42 struct hdb_method {
  43     const char *prefix;
  44     krb5_error_code (*create)(krb5_context, HDB **, const char *filename);
  45 };
  46
  47 static struct hdb_method methods[] = {
  48 #if HAVE_DB1 || HAVE_DB3
  49     {"db:",     hdb_db_create},
  50 #endif
  51 #if HAVE_NDBM
  52     {"ndbm:",   hdb_ndbm_create},
  53 #endif
  54 #if defined(OPENLDAP) && !defined(OPENLDAP_MODULE)
  55     {"ldap:",   hdb_ldap_create},
  56     {"ldapi:",  hdb_ldapi_create},
  57 #endif
  58 #ifdef HAVE_LDB /* Used for integrated samba build */
  59     {"ldb:",    hdb_ldb_create},
  60 #endif
  61     {NULL,      NULL}
  62 };
  63
  64 #if HAVE_DB1 || HAVE_DB3
  65 static struct hdb_method dbmetod = {"", hdb_db_create };
  66 #elif defined(HAVE_NDBM)
  67 static struct hdb_method dbmetod = {"", hdb_ndbm_create };
  68 #endif
  69
  70
  71 krb5_error_code
  72 hdb_next_enctype2key(krb5_context context,
  73                      const hdb_entry *e,
  74                      krb5_enctype enctype,
  75                      Key **key)
  76 {
  77     Key *k;
  78
  79     for (k = *key ? (*key) + 1 : e->keys.val;
  80          k < e->keys.val + e->keys.len;
  81          k++)
  82     {
  83         if(k->key.keytype == enctype){
  84             *key = k;
  85             return 0;
  86         }
  87     }
  88     krb5_set_error_string(context, "No next enctype %d for hdb-entry",
  89                           (int)enctype);
  90     return KRB5_PROG_ETYPE_NOSUPP; /* XXX */
  91 }
  92
  93 krb5_error_code
  94 hdb_enctype2key(krb5_context context,
  95                 hdb_entry *e,
  96                 krb5_enctype enctype,
  97                 Key **key)
  98 {
  99     *key = NULL;
 100     return hdb_next_enctype2key(context, e, enctype, key);
 101 }
 102
 103 void
 104 hdb_free_key(Key *key)
 105 {
 106     memset(key->key.keyvalue.data,
 107            0,
 108            key->key.keyvalue.length);
 109     free_Key(key);
 110     free(key);
 111 }
 112
 113
 114 krb5_error_code
 115 hdb_lock(int fd, int operation)
 116 {
 117     int i, code = 0;
 118
 119     for(i = 0; i < 3; i++){
 120         code = flock(fd, (operation == HDB_RLOCK ? LOCK_SH : LOCK_EX) | LOCK_NB);
 121         if(code == 0 || errno != EWOULDBLOCK)
 122             break;
 123         sleep(1);
 124     }
 125     if(code == 0)
 126         return 0;
 127     if(errno == EWOULDBLOCK)
 128         return HDB_ERR_DB_INUSE;
 129     return HDB_ERR_CANT_LOCK_DB;
 130 }
 131
 132 krb5_error_code
 133 hdb_unlock(int fd)
 134 {
 135     int code;
 136     code = flock(fd, LOCK_UN);
 137     if(code)
 138         return 4711 /* XXX */;
 139     return 0;
 140 }
 141
 142 void
 143 hdb_free_entry(krb5_context context, hdb_entry_ex *ent)
 144 {
 145     int i;
 146
 147     if (ent->free_entry)
 148         (*ent->free_entry)(context, ent);
 149
 150     for(i = 0; i < ent->entry.keys.len; ++i) {
 151         Key *k = &ent->entry.keys.val[i];
 152
 153         memset (k->key.keyvalue.data, 0, k->key.keyvalue.length);
 154     }
 155     free_hdb_entry(&ent->entry);
 156 }
 157
 158 krb5_error_code
 159 hdb_foreach(krb5_context context,
 160             HDB *db,
 161             unsigned flags,
 162             hdb_foreach_func_t func,
 163             void *data)
 164 {
 165     krb5_error_code ret;
 166     hdb_entry_ex entry;
 167     ret = db->hdb_firstkey(context, db, flags, &entry);
 168     if (ret == 0)
 169         krb5_clear_error_string(context);
 170     while(ret == 0){
 171         ret = (*func)(context, db, &entry, data);
 172         hdb_free_entry(context, &entry);
 173         if(ret == 0)
 174             ret = db->hdb_nextkey(context, db, flags, &entry);
 175     }
 176     if(ret == HDB_ERR_NOENTRY)
 177         ret = 0;
 178     return ret;
 179 }
 180
 181 krb5_error_code
 182 hdb_check_db_format(krb5_context context, HDB *db)
 183 {
 184     krb5_data tag;
 185     krb5_data version;
 186     krb5_error_code ret, ret2;
 187     unsigned ver;
 188     int foo;
 189
 190     ret = db->hdb_lock(context, db, HDB_RLOCK);
 191     if (ret)
 192         return ret;
 193
 194     tag.data = HDB_DB_FORMAT_ENTRY;
 195     tag.length = strlen(tag.data);
 196     ret = (*db->hdb__get)(context, db, tag, &version);
 197     ret2 = db->hdb_unlock(context, db);
 198     if(ret)
 199         return ret;
 200     if (ret2)
 201         return ret2;
 202     foo = sscanf(version.data, "%u", &ver);
 203     krb5_data_free (&version);
 204     if (foo != 1)
 205         return HDB_ERR_BADVERSION;
 206     if(ver != HDB_DB_FORMAT)
 207         return HDB_ERR_BADVERSION;
 208     return 0;
 209 }
 210
 211 krb5_error_code
 212 hdb_init_db(krb5_context context, HDB *db)
 213 {
 214     krb5_error_code ret, ret2;
 215     krb5_data tag;
 216     krb5_data version;
 217     char ver[32];
 218
 219     ret = hdb_check_db_format(context, db);
 220     if(ret != HDB_ERR_NOENTRY)
 221         return ret;
 222
 223     ret = db->hdb_lock(context, db, HDB_WLOCK);
 224     if (ret)
 225         return ret;
 226
 227     tag.data = HDB_DB_FORMAT_ENTRY;
 228     tag.length = strlen(tag.data);
 229     snprintf(ver, sizeof(ver), "%u", HDB_DB_FORMAT);
 230     version.data = ver;
 231     version.length = strlen(version.data) + 1; /* zero terminated */
 232     ret = (*db->hdb__put)(context, db, 0, tag, version);
 233     ret2 = db->hdb_unlock(context, db);
 234     if (ret) {
 235         if (ret2)
 236             krb5_clear_error_string(context);
 237         return ret;
 238     }
 239     return ret2;
 240 }
 241
 242 #ifdef HAVE_DLOPEN
 243
 244  /*
 245  * Load a dynamic backend from /usr/heimdal/lib/hdb_NAME.so,
 246  * looking for the hdb_NAME_create symbol.
 247  */
 248
 249 static const struct hdb_method *
 250 find_dynamic_method (krb5_context context,
 251                      const char *filename,
 252                      const char **rest)
 253 {
 254     static struct hdb_method method;
 255     struct hdb_so_method *mso;
 256     char *prefix, *path, *symbol;
 257     const char *p;
 258     void *dl;
 259     size_t len;
 260
 261     p = strchr(filename, ':');
 262
 263     /* if no prefix, don't know what module to load, just ignore it */
 264     if (p == NULL)
 265         return NULL;
 266
 267     len = p - filename;
 268     *rest = filename + len + 1;
 269
 270     prefix = strndup(filename, len);
 271     if (prefix == NULL)
 272         krb5_errx(context, 1, "out of memory");
 273
 274     if (asprintf(&path, LIBDIR "/hdb_%s.so", prefix) == -1)
 275         krb5_errx(context, 1, "out of memory");
 276
 277 #ifndef RTLD_NOW
 278 #define RTLD_NOW 0
 279 #endif
 280 #ifndef RTLD_GLOBAL
 281 #define RTLD_GLOBAL 0
 282 #endif
 283
 284     dl = dlopen(path, RTLD_NOW | RTLD_GLOBAL);
 285     if (dl == NULL) {
 286         krb5_warnx(context, "error trying to load dynamic module %s: %s\n",
 287                    path, dlerror());
 288         free(prefix);
 289         free(path);
 290         return NULL;
 291     }
 292
 293     if (asprintf(&symbol, "hdb_%s_interface", prefix) == -1)
 294         krb5_errx(context, 1, "out of memory");
 295
 296     mso = dlsym(dl, symbol);
 297     if (mso == NULL) {
 298         krb5_warnx(context, "error finding symbol %s in %s: %s\n",
 299                    symbol, path, dlerror());
 300         dlclose(dl);
 301         free(symbol);
 302         free(prefix);
 303         free(path);
 304         return NULL;
 305     }
 306     free(path);
 307     free(symbol);
 308
 309     if (mso->version != HDB_INTERFACE_VERSION) {
 310         krb5_warnx(context,
 311                    "error wrong version in shared module %s "
 312                    "version: %d should have been %d\n",
 313                    prefix, mso->version, HDB_INTERFACE_VERSION);
 314         dlclose(dl);
 315         free(prefix);
 316         return NULL;
 317     }
 318
 319     if (mso->create == NULL) {
 320         krb5_errx(context, 1,
 321                   "no entry point function in shared mod %s ",
 322                    prefix);
 323         dlclose(dl);
 324         free(prefix);
 325         return NULL;
 326     }
 327
 328     method.create = mso->create;
 329     method.prefix = prefix;
 330
 331     return &method;
 332 }
 333 #endif /* HAVE_DLOPEN */
 334
 335 /*
 336  * find the relevant method for `filename', returning a pointer to the
 337  * rest in `rest'.
 338  * return NULL if there's no such method.
 339  */
 340
 341 static const struct hdb_method *
 342 find_method (const char *filename, const char **rest)
 343 {
 344     const struct hdb_method *h;
 345
 346     for (h = methods; h->prefix != NULL; ++h) {
 347         if (strncmp (filename, h->prefix, strlen(h->prefix)) == 0) {
 348             *rest = filename + strlen(h->prefix);
 349             return h;
 350         }
 351     }
 352 #if defined(HAVE_DB1) || defined(HAVE_DB3) || defined(HAVE_NDBM)
 353     if (strncmp(filename, "/", 1) == 0
 354         || strncmp(filename, "./", 2) == 0
 355         || strncmp(filename, "../", 3) == 0)
 356     {
 357         *rest = filename;
 358         return &dbmetod;
 359     }
 360 #endif
 361
 362     return NULL;
 363 }
 364
 365 krb5_error_code
 366 hdb_list_builtin(krb5_context context, char **list)
 367 {
 368     const struct hdb_method *h;
 369     size_t len = 0;
 370     char *buf = NULL;
 371
 372     for (h = methods; h->prefix != NULL; ++h) {
 373         if (h->prefix[0] == '\0')
 374             continue;
 375         len += strlen(h->prefix) + 2;
 376     }
 377
 378     len += 1;
 379     buf = malloc(len);
 380     if (buf == NULL) {
 381         krb5_set_error_string(context, "malloc: out of memory");
 382         return ENOMEM;
 383     }
 384     buf[0] = '\0';
 385
 386     for (h = methods; h->prefix != NULL; ++h) {
 387         if (h != methods)
 388             strlcat(buf, ", ", len);
 389         strlcat(buf, h->prefix, len);
 390     }
 391     *list = buf;
 392     return 0;
 393 }
 394
 395 krb5_error_code
 396 hdb_create(krb5_context context, HDB **db, const char *filename)
 397 {
 398     const struct hdb_method *h;
 399     const char *residual;
 400
 401     if(filename == NULL)
 402         filename = HDB_DEFAULT_DB;
 403     krb5_add_et_list(context, initialize_hdb_error_table_r);
 404     h = find_method (filename, &residual);
 405 #ifdef HAVE_DLOPEN
 406     if (h == NULL)
 407         h = find_dynamic_method (context, filename, &residual);
 408 #endif
 409     if (h == NULL)
 410         krb5_errx(context, 1, "No database support for %s", filename);
 411     return (*h->create)(context, db, residual);
 412 }