lib/kafs/common.c

   1 /*
   2  * Copyright (c) 1997 - 2005 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 "kafs_locl.h"
  35
  36 #define AUTH_SUPERUSER "afs"
  37
  38 /*
  39  * Here only ASCII characters are relevant.
  40  */
  41
  42 #define IsAsciiLower(c) ('a' <= (c) && (c) <= 'z')
  43
  44 #define ToAsciiUpper(c) ((c) - 'a' + 'A')
  45
  46 static void (*kafs_verbose)(void *, const char *);
  47 static void *kafs_verbose_ctx;
  48
  49 void
  50 _kafs_foldup(char *a, const char *b)
  51 {
  52   for (; *b; a++, b++)
  53     if (IsAsciiLower(*b))
  54       *a = ToAsciiUpper(*b);
  55     else
  56       *a = *b;
  57   *a = '\0';
  58 }
  59
  60 void
  61 kafs_set_verbose(void (*f)(void *, const char *), void *ctx)
  62 {
  63     if (f) {
  64         kafs_verbose = f;
  65         kafs_verbose_ctx = ctx;
  66     }
  67 }
  68
  69 int
  70 kafs_settoken_rxkad(const char *cell, struct ClearToken *ct,
  71                     void *ticket, size_t ticket_len)
  72 {
  73     struct ViceIoctl parms;
  74     char buf[2048], *t;
  75     int32_t sizeof_x;
  76
  77     t = buf;
  78     /*
  79      * length of secret token followed by secret token
  80      */
  81     sizeof_x = ticket_len;
  82     memcpy(t, &sizeof_x, sizeof(sizeof_x));
  83     t += sizeof(sizeof_x);
  84     memcpy(t, ticket, sizeof_x);
  85     t += sizeof_x;
  86     /*
  87      * length of clear token followed by clear token
  88      */
  89     sizeof_x = sizeof(*ct);
  90     memcpy(t, &sizeof_x, sizeof(sizeof_x));
  91     t += sizeof(sizeof_x);
  92     memcpy(t, ct, sizeof_x);
  93     t += sizeof_x;
  94
  95     /*
  96      * do *not* mark as primary cell
  97      */
  98     sizeof_x = 0;
  99     memcpy(t, &sizeof_x, sizeof(sizeof_x));
 100     t += sizeof(sizeof_x);
 101     /*
 102      * follow with cell name
 103      */
 104     sizeof_x = strlen(cell) + 1;
 105     memcpy(t, cell, sizeof_x);
 106     t += sizeof_x;
 107
 108     /*
 109      * Build argument block
 110      */
 111     parms.in = buf;
 112     parms.in_size = t - buf;
 113     parms.out = 0;
 114     parms.out_size = 0;
 115
 116     return k_pioctl(0, VIOCSETTOK, &parms, 0);
 117 }
 118
 119 void
 120 _kafs_fixup_viceid(struct ClearToken *ct, uid_t uid)
 121 {
 122 #define ODD(x) ((x) & 1)
 123     /* According to Transarc conventions ViceId is valid iff
 124      * (EndTimestamp - BeginTimestamp) is odd. By decrementing EndTime
 125      * the transformations:
 126      *
 127      * (issue_date, life) -> (StartTime, EndTime) -> (issue_date, life)
 128      * preserves the original values.
 129      */
 130     if (uid != 0)               /* valid ViceId */
 131     {
 132         if (!ODD(ct->EndTimestamp - ct->BeginTimestamp))
 133             ct->EndTimestamp--;
 134     }
 135     else                        /* not valid ViceId */
 136     {
 137         if (ODD(ct->EndTimestamp - ct->BeginTimestamp))
 138             ct->EndTimestamp--;
 139     }
 140 }
 141
 142 /* Try to get a db-server for an AFS cell from a AFSDB record */
 143
 144 static int
 145 dns_find_cell(const char *cell, char *dbserver, size_t len)
 146 {
 147     struct rk_dns_reply *r;
 148     int ok = -1;
 149     r = rk_dns_lookup(cell, "afsdb");
 150     if(r){
 151         struct rk_resource_record *rr = r->head;
 152         while(rr){
 153             if(rr->type == rk_ns_t_afsdb && rr->u.afsdb->preference == 1){
 154                 strlcpy(dbserver,
 155                                 rr->u.afsdb->domain,
 156                                 len);
 157                 ok = 0;
 158                 break;
 159             }
 160             rr = rr->next;
 161         }
 162         rk_dns_free_data(r);
 163     }
 164     return ok;
 165 }
 166
 167
 168 /*
 169  * Try to find the cells we should try to klog to in "file".
 170  */
 171 static void
 172 find_cells(const char *file, char ***cells, int *idx)
 173 {
 174     FILE *f;
 175     char cell[64];
 176     int i;
 177     int ind = *idx;
 178
 179     f = fopen(file, "r");
 180     if (f == NULL)
 181         return;
 182     while (fgets(cell, sizeof(cell), f)) {
 183         char *t;
 184         t = cell + strlen(cell);
 185         for (; t >= cell; t--)
 186           if (*t == '\n' || *t == '\t' || *t == ' ')
 187             *t = 0;
 188         if (cell[0] == '\0' || cell[0] == '#')
 189             continue;
 190         for(i = 0; i < ind; i++)
 191             if(strcmp((*cells)[i], cell) == 0)
 192                 break;
 193         if(i == ind){
 194             char **tmp;
 195
 196             tmp = realloc(*cells, (ind + 1) * sizeof(**cells));
 197             if (tmp == NULL)
 198                 break;
 199             *cells = tmp;
 200             (*cells)[ind] = strdup(cell);
 201             if ((*cells)[ind] == NULL)
 202                 break;
 203             ++ind;
 204         }
 205     }
 206     fclose(f);
 207     *idx = ind;
 208 }
 209
 210 /*
 211  * Get tokens for all cells[]
 212  */
 213 static int
 214 afslog_cells(struct kafs_data *data, char **cells, int max, uid_t uid,
 215              const char *homedir)
 216 {
 217     int ret = 0;
 218     int i;
 219     for (i = 0; i < max; i++) {
 220         int er = (*data->afslog_uid)(data, cells[i], 0, uid, homedir);
 221         if (er)
 222             ret = er;
 223     }
 224     return ret;
 225 }
 226
 227 int
 228 _kafs_afslog_all_local_cells(struct kafs_data *data,
 229                              uid_t uid, const char *homedir)
 230 {
 231     int ret;
 232     char **cells = NULL;
 233     int idx = 0;
 234
 235     if (homedir == NULL)
 236         homedir = getenv("HOME");
 237     if (homedir != NULL) {
 238         char home[MaxPathLen];
 239         snprintf(home, sizeof(home), "%s/.TheseCells", homedir);
 240         find_cells(home, &cells, &idx);
 241     }
 242     find_cells(_PATH_THESECELLS, &cells, &idx);
 243     find_cells(_PATH_THISCELL, &cells, &idx);
 244     find_cells(_PATH_ARLA_THESECELLS, &cells, &idx);
 245     find_cells(_PATH_ARLA_THISCELL, &cells, &idx);
 246     find_cells(_PATH_OPENAFS_DEBIAN_THESECELLS, &cells, &idx);
 247     find_cells(_PATH_OPENAFS_DEBIAN_THISCELL, &cells, &idx);
 248     find_cells(_PATH_OPENAFS_MACOSX_THESECELLS, &cells, &idx);
 249     find_cells(_PATH_OPENAFS_MACOSX_THISCELL, &cells, &idx);
 250     find_cells(_PATH_ARLA_DEBIAN_THESECELLS, &cells, &idx);
 251     find_cells(_PATH_ARLA_DEBIAN_THISCELL, &cells, &idx);
 252     find_cells(_PATH_ARLA_OPENBSD_THESECELLS, &cells, &idx);
 253     find_cells(_PATH_ARLA_OPENBSD_THISCELL, &cells, &idx);
 254
 255     ret = afslog_cells(data, cells, idx, uid, homedir);
 256     while(idx > 0)
 257         free(cells[--idx]);
 258     free(cells);
 259     return ret;
 260 }
 261
 262
 263 static int
 264 file_find_cell(struct kafs_data *data,
 265                const char *cell, char **realm, int exact)
 266 {
 267     FILE *F;
 268     char buf[1024];
 269     char *p;
 270     int ret = -1;
 271
 272     if ((F = fopen(_PATH_CELLSERVDB, "r"))
 273         || (F = fopen(_PATH_ARLA_CELLSERVDB, "r"))
 274         || (F = fopen(_PATH_OPENAFS_DEBIAN_CELLSERVDB, "r"))
 275         || (F = fopen(_PATH_OPENAFS_MACOSX_CELLSERVDB, "r"))
 276         || (F = fopen(_PATH_ARLA_DEBIAN_CELLSERVDB, "r"))) {
 277         while (fgets(buf, sizeof(buf), F)) {
 278             int cmp;
 279
 280             if (buf[0] != '>')
 281                 continue; /* Not a cell name line, try next line */
 282             p = buf;
 283             strsep(&p, " \t\n#");
 284
 285             if (exact)
 286                 cmp = strcmp(buf + 1, cell);
 287             else
 288                 cmp = strncmp(buf + 1, cell, strlen(cell));
 289
 290             if (cmp == 0) {
 291                 /*
 292                  * We found the cell name we're looking for.
 293                  * Read next line on the form ip-address '#' hostname
 294                  */
 295                 if (fgets(buf, sizeof(buf), F) == NULL)
 296                     break;      /* Read failed, give up */
 297                 p = strchr(buf, '#');
 298                 if (p == NULL)
 299                     break;      /* No '#', give up */
 300                 p++;
 301                 if (buf[strlen(buf) - 1] == '\n')
 302                     buf[strlen(buf) - 1] = '\0';
 303                 *realm = (*data->get_realm)(data, p);
 304                 if (*realm && **realm != '\0')
 305                     ret = 0;
 306                 break;          /* Won't try any more */
 307             }
 308         }
 309         fclose(F);
 310     }
 311     return ret;
 312 }
 313
 314 /* Find the realm associated with cell. Do this by opening CellServDB
 315    file and getting the realm-of-host for the first VL-server for the
 316    cell.
 317
 318    This does not work when the VL-server is living in one realm, but
 319    the cell it is serving is living in another realm.
 320
 321    Return 0 on success, -1 otherwise.
 322    */
 323
 324 int
 325 _kafs_realm_of_cell(struct kafs_data *data,
 326                     const char *cell, char **realm)
 327 {
 328     char buf[1024];
 329     int ret;
 330
 331     ret = file_find_cell(data, cell, realm, 1);
 332     if (ret == 0)
 333         return ret;
 334     if (dns_find_cell(cell, buf, sizeof(buf)) == 0) {
 335         *realm = (*data->get_realm)(data, buf);
 336         if(*realm != NULL)
 337             return 0;
 338     }
 339     return file_find_cell(data, cell, realm, 0);
 340 }
 341
 342 static int
 343 _kafs_try_get_cred(struct kafs_data *data, const char *user, const char *cell,
 344                    const char *realm, uid_t uid, struct kafs_token *kt)
 345 {
 346     int ret;
 347
 348     ret = (*data->get_cred)(data, user, cell, realm, uid, kt);
 349     if (kafs_verbose) {
 350         const char *estr = (*data->get_error)(data, ret);
 351         char *str;
 352         int aret;
 353
 354         aret = asprintf(&str, "%s tried afs%s%s@%s -> %s (%d)",
 355                         data->name, cell ? "/" : "",
 356                         cell ? cell : "", realm, estr ? estr : "unknown", ret);
 357         if (aret != -1) {
 358             (*kafs_verbose)(kafs_verbose_ctx, str);
 359             free(str);
 360         } else {
 361             (*kafs_verbose)(kafs_verbose_ctx, "out of memory");
 362         }
 363         if (estr)
 364             (*data->free_error)(data, estr);
 365     }
 366
 367     return ret;
 368 }
 369
 370
 371 int
 372 _kafs_get_cred(struct kafs_data *data,
 373                const char *cell,
 374                const char *realm_hint,
 375                const char *realm,
 376                uid_t uid,
 377                struct kafs_token *kt)
 378 {
 379     int ret = -1;
 380     char *vl_realm;
 381     char CELL[64];
 382
 383     /* We're about to find the realm that holds the key for afs in
 384      * the specified cell. The problem is that null-instance
 385      * afs-principals are common and that hitting the wrong realm might
 386      * yield the wrong afs key. The following assumptions were made.
 387      *
 388      * Any realm passed to us is preferred.
 389      *
 390      * If there is a realm with the same name as the cell, it is most
 391      * likely the correct realm to talk to.
 392      *
 393      * In most (maybe even all) cases the database servers of the cell
 394      * will live in the realm we are looking for.
 395      *
 396      * Try the local realm, but if the previous cases fail, this is
 397      * really a long shot.
 398      *
 399      */
 400
 401     /* comments on the ordering of these tests */
 402
 403     /* If the user passes a realm, she probably knows something we don't
 404      * know and we should try afs@realm_hint.
 405      */
 406
 407     if (realm_hint) {
 408         ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 409                                  cell, realm_hint, uid, kt);
 410         if (ret == 0) return 0;
 411         ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 412                                  NULL, realm_hint, uid, kt);
 413         if (ret == 0) return 0;
 414     }
 415
 416     _kafs_foldup(CELL, cell);
 417
 418     /*
 419      * If the AFS servers have a file /usr/afs/etc/krb.conf containing
 420      * REALM we still don't have to resort to cross-cell authentication.
 421      * Try afs.cell@REALM.
 422      */
 423     ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 424                              cell, realm, uid, kt);
 425     if (ret == 0) return 0;
 426
 427     /*
 428      * If cell == realm we don't need no cross-cell authentication.
 429      * Try afs@REALM.
 430      */
 431     if (strcmp(CELL, realm) == 0) {
 432         ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 433                                  NULL, realm, uid, kt);
 434         if (ret == 0) return 0;
 435     }
 436
 437     /*
 438      * We failed to get ``first class tickets'' for afs,
 439      * fall back to cross-cell authentication.
 440      * Try afs@CELL.
 441      * Try afs.cell@CELL.
 442      */
 443     ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 444                              NULL, CELL, uid, kt);
 445     if (ret == 0) return 0;
 446     ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 447                              cell, CELL, uid, kt);
 448     if (ret == 0) return 0;
 449
 450     /*
 451      * Perhaps the cell doesn't correspond to any realm?
 452      * Use realm of first volume location DB server.
 453      * Try afs.cell@VL_REALM.
 454      * Try afs@VL_REALM???
 455      */
 456     if (_kafs_realm_of_cell(data, cell, &vl_realm) == 0
 457         && strcmp(vl_realm, realm) != 0
 458         && strcmp(vl_realm, CELL) != 0) {
 459         ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 460                                  cell, vl_realm, uid, kt);
 461         if (ret)
 462             ret = _kafs_try_get_cred(data, AUTH_SUPERUSER,
 463                                      NULL, vl_realm, uid, kt);
 464         free(vl_realm);
 465         if (ret == 0) return 0;
 466     }
 467
 468     return ret;
 469 }