lib/krb5/fcache.c

   1 /*
   2  * Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Portions Copyright (c) 2009 Apple Inc. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "krb5_locl.h"
  37
  38 typedef struct krb5_fcache{
  39     char *filename;
  40     int version;
  41 }krb5_fcache;
  42
  43 struct fcc_cursor {
  44     int fd;
  45     off_t cred_start;
  46     off_t cred_end;
  47     krb5_storage *sp;
  48 };
  49
  50 #define KRB5_FCC_FVNO_1 1
  51 #define KRB5_FCC_FVNO_2 2
  52 #define KRB5_FCC_FVNO_3 3
  53 #define KRB5_FCC_FVNO_4 4
  54
  55 #define FCC_TAG_DELTATIME 1
  56
  57 #define FCACHE(X) ((krb5_fcache*)(X)->data.data)
  58
  59 #define FILENAME(X) (FCACHE(X)->filename)
  60
  61 #define FCC_CURSOR(C) ((struct fcc_cursor*)(C))
  62
  63 static const char* KRB5_CALLCONV
  64 fcc_get_name(krb5_context context,
  65              krb5_ccache id)
  66 {
  67     if (FCACHE(id) == NULL)
  68         return NULL;
  69
  70     return FILENAME(id);
  71 }
  72
  73 KRB5_LIB_FUNCTION int KRB5_LIB_CALL
  74 _krb5_xlock(krb5_context context, int fd, krb5_boolean exclusive,
  75             const char *filename)
  76 {
  77     int ret;
  78 #ifdef HAVE_FCNTL
  79     struct flock l;
  80
  81     l.l_start = 0;
  82     l.l_len = 0;
  83     l.l_type = exclusive ? F_WRLCK : F_RDLCK;
  84     l.l_whence = SEEK_SET;
  85     ret = fcntl(fd, F_SETLKW, &l);
  86 #else
  87     ret = flock(fd, exclusive ? LOCK_EX : LOCK_SH);
  88 #endif
  89     if(ret < 0)
  90         ret = errno;
  91     if(ret == EACCES) /* fcntl can return EACCES instead of EAGAIN */
  92         ret = EAGAIN;
  93
  94     switch (ret) {
  95     case 0:
  96         break;
  97     case EINVAL: /* filesystem doesn't support locking, let the user have it */
  98         ret = 0;
  99         break;
 100     case EAGAIN:
 101         krb5_set_error_message(context, ret,
 102                                N_("timed out locking cache file %s", "file"),
 103                                filename);
 104         break;
 105     default: {
 106         char buf[128];
 107         rk_strerror_r(ret, buf, sizeof(buf));
 108         krb5_set_error_message(context, ret,
 109                                N_("error locking cache file %s: %s",
 110                                   "file, error"), filename, buf);
 111         break;
 112     }
 113     }
 114     return ret;
 115 }
 116
 117 KRB5_LIB_FUNCTION int KRB5_LIB_CALL
 118 _krb5_xunlock(krb5_context context, int fd)
 119 {
 120     int ret;
 121 #ifdef HAVE_FCNTL
 122     struct flock l;
 123     l.l_start = 0;
 124     l.l_len = 0;
 125     l.l_type = F_UNLCK;
 126     l.l_whence = SEEK_SET;
 127     ret = fcntl(fd, F_SETLKW, &l);
 128 #else
 129     ret = flock(fd, LOCK_UN);
 130 #endif
 131     if (ret < 0)
 132         ret = errno;
 133     switch (ret) {
 134     case 0:
 135         break;
 136     case EINVAL: /* filesystem doesn't support locking, let the user have it */
 137         ret = 0;
 138         break;
 139     default: {
 140         char buf[128];
 141         rk_strerror_r(ret, buf, sizeof(buf));
 142         krb5_set_error_message(context, ret,
 143                                N_("Failed to unlock file: %s", ""), buf);
 144         break;
 145     }
 146     }
 147     return ret;
 148 }
 149
 150 static krb5_error_code
 151 write_storage(krb5_context context, krb5_storage *sp, int fd)
 152 {
 153     krb5_error_code ret;
 154     krb5_data data;
 155     ssize_t sret;
 156
 157     ret = krb5_storage_to_data(sp, &data);
 158     if (ret) {
 159         krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
 160         return ret;
 161     }
 162     sret = write(fd, data.data, data.length);
 163     ret = (sret != (ssize_t)data.length);
 164     krb5_data_free(&data);
 165     if (ret) {
 166         ret = errno;
 167         krb5_set_error_message(context, ret,
 168                                N_("Failed to write FILE credential data", ""));
 169         return ret;
 170     }
 171     return 0;
 172 }
 173
 174
 175 static krb5_error_code KRB5_CALLCONV
 176 fcc_lock(krb5_context context, krb5_ccache id,
 177          int fd, krb5_boolean exclusive)
 178 {
 179     return _krb5_xlock(context, fd, exclusive, fcc_get_name(context, id));
 180 }
 181
 182 static krb5_error_code KRB5_CALLCONV
 183 fcc_unlock(krb5_context context, int fd)
 184 {
 185     return _krb5_xunlock(context, fd);
 186 }
 187
 188 static krb5_error_code KRB5_CALLCONV
 189 fcc_resolve(krb5_context context, krb5_ccache *id, const char *res)
 190 {
 191     krb5_fcache *f;
 192     f = malloc(sizeof(*f));
 193     if(f == NULL) {
 194         krb5_set_error_message(context, KRB5_CC_NOMEM,
 195                                N_("malloc: out of memory", ""));
 196         return KRB5_CC_NOMEM;
 197     }
 198     f->filename = strdup(res);
 199     if(f->filename == NULL){
 200         free(f);
 201         krb5_set_error_message(context, KRB5_CC_NOMEM,
 202                                N_("malloc: out of memory", ""));
 203         return KRB5_CC_NOMEM;
 204     }
 205     f->version = 0;
 206     (*id)->data.data = f;
 207     (*id)->data.length = sizeof(*f);
 208     return 0;
 209 }
 210
 211 /*
 212  * Try to scrub the contents of `filename' safely.
 213  */
 214
 215 static int
 216 scrub_file (int fd)
 217 {
 218     off_t pos;
 219     char buf[128];
 220
 221     pos = lseek(fd, 0, SEEK_END);
 222     if (pos < 0)
 223         return errno;
 224     if (lseek(fd, 0, SEEK_SET) < 0)
 225         return errno;
 226     memset(buf, 0, sizeof(buf));
 227     while(pos > 0) {
 228         ssize_t tmp;
 229         size_t wr = sizeof(buf);
 230         if (wr > pos)
 231             wr = (size_t)pos;
 232         tmp = write(fd, buf, wr);
 233
 234         if (tmp < 0)
 235             return errno;
 236         pos -= tmp;
 237     }
 238 #ifdef _MSC_VER
 239     _commit (fd);
 240 #else
 241     fsync (fd);
 242 #endif
 243     return 0;
 244 }
 245
 246 /*
 247  * Erase `filename' if it exists, trying to remove the contents if
 248  * it's `safe'.  We always try to remove the file, it it exists.  It's
 249  * only overwritten if it's a regular file (not a symlink and not a
 250  * hardlink)
 251  */
 252
 253 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 254 _krb5_erase_file(krb5_context context, const char *filename)
 255 {
 256     int fd;
 257     struct stat sb1, sb2;
 258     int ret;
 259
 260     ret = lstat (filename, &sb1);
 261     if (ret < 0)
 262         return errno;
 263
 264     fd = open(filename, O_RDWR | O_BINARY | O_CLOEXEC | O_NOFOLLOW);
 265     if(fd < 0) {
 266         if(errno == ENOENT)
 267             return 0;
 268         else
 269             return errno;
 270     }
 271     rk_cloexec(fd);
 272     ret = _krb5_xlock(context, fd, 1, filename);
 273     if (ret) {
 274         close(fd);
 275         return ret;
 276     }
 277     if (unlink(filename) < 0) {
 278         _krb5_xunlock(context, fd);
 279         close (fd);
 280         return errno;
 281     }
 282     ret = fstat(fd, &sb2);
 283     if (ret < 0) {
 284         _krb5_xunlock(context, fd);
 285         close (fd);
 286         return errno;
 287     }
 288
 289     /* check if someone was playing with symlinks */
 290
 291     if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino) {
 292         _krb5_xunlock(context, fd);
 293         close(fd);
 294         return EPERM;
 295     }
 296
 297     /* there are still hard links to this file */
 298
 299     if (sb2.st_nlink != 0) {
 300         _krb5_xunlock(context, fd);
 301         close(fd);
 302         return 0;
 303     }
 304
 305     ret = scrub_file(fd);
 306     if (ret) {
 307         _krb5_xunlock(context, fd);
 308         close(fd);
 309         return ret;
 310     }
 311     ret = _krb5_xunlock(context, fd);
 312     close(fd);
 313     return ret;
 314 }
 315
 316 static krb5_error_code KRB5_CALLCONV
 317 fcc_gen_new(krb5_context context, krb5_ccache *id)
 318 {
 319     char *file = NULL, *exp_file = NULL;
 320     krb5_error_code ret;
 321     krb5_fcache *f;
 322     int fd;
 323
 324     f = malloc(sizeof(*f));
 325     if(f == NULL) {
 326         krb5_set_error_message(context, KRB5_CC_NOMEM,
 327                                N_("malloc: out of memory", ""));
 328         return KRB5_CC_NOMEM;
 329     }
 330     ret = asprintf(&file, "%sXXXXXX", KRB5_DEFAULT_CCFILE_ROOT);
 331     if(ret < 0 || file == NULL) {
 332         free(f);
 333         krb5_set_error_message(context, KRB5_CC_NOMEM,
 334                                N_("malloc: out of memory", ""));
 335         return KRB5_CC_NOMEM;
 336     }
 337     ret = _krb5_expand_path_tokens(context, file, 1, &exp_file);
 338     free(file);
 339     if (ret) {
 340         free(f);
 341         return ret;
 342     }
 343
 344     file = exp_file;
 345
 346     fd = mkstemp(exp_file);
 347     if(fd < 0) {
 348         ret = (krb5_error_code)errno;
 349         krb5_set_error_message(context, ret, N_("mkstemp %s failed", ""), exp_file);
 350         free(f);
 351         free(exp_file);
 352         return ret;
 353     }
 354     close(fd);
 355     f->filename = exp_file;
 356     f->version = 0;
 357     (*id)->data.data = f;
 358     (*id)->data.length = sizeof(*f);
 359     return 0;
 360 }
 361
 362 static void
 363 storage_set_flags(krb5_context context, krb5_storage *sp, int vno)
 364 {
 365     int flags = 0;
 366     switch(vno) {
 367     case KRB5_FCC_FVNO_1:
 368         flags |= KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS;
 369         flags |= KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE;
 370         flags |= KRB5_STORAGE_HOST_BYTEORDER;
 371         break;
 372     case KRB5_FCC_FVNO_2:
 373         flags |= KRB5_STORAGE_HOST_BYTEORDER;
 374         break;
 375     case KRB5_FCC_FVNO_3:
 376         flags |= KRB5_STORAGE_KEYBLOCK_KEYTYPE_TWICE;
 377         break;
 378     case KRB5_FCC_FVNO_4:
 379         break;
 380     default:
 381         krb5_abortx(context,
 382                     "storage_set_flags called with bad vno (%x)", vno);
 383     }
 384     krb5_storage_set_flags(sp, flags);
 385 }
 386
 387 static krb5_error_code KRB5_CALLCONV
 388 fcc_open(krb5_context context,
 389          krb5_ccache id,
 390          const char *operation,
 391          int *fd_ret,
 392          int flags,
 393          mode_t mode)
 394 {
 395     krb5_boolean exclusive = ((flags | O_WRONLY) == flags ||
 396                               (flags | O_RDWR) == flags);
 397     krb5_error_code ret;
 398     const char *filename;
 399     struct stat sb1, sb2;
 400 #ifndef _WIN32
 401     struct stat sb3;
 402     size_t tries = 3;
 403 #endif
 404     int strict_checking;
 405     int fd;
 406
 407     flags |= O_BINARY | O_CLOEXEC | O_NOFOLLOW;
 408
 409     *fd_ret = -1;
 410
 411     if (FCACHE(id) == NULL)
 412         return krb5_einval(context, 2);
 413
 414     filename = FILENAME(id);
 415
 416     strict_checking = (flags & O_CREAT) == 0 &&
 417         (context->flags & KRB5_CTX_F_FCACHE_STRICT_CHECKING) != 0;
 418
 419 again:
 420     memset(&sb1, 0, sizeof(sb1));
 421     ret = lstat(filename, &sb1);
 422     if (ret == 0) {
 423         if (!S_ISREG(sb1.st_mode)) {
 424             krb5_set_error_message(context, EPERM,
 425                                    N_("Refuses to open symlinks for caches FILE:%s", ""), filename);
 426             return EPERM;
 427         }
 428     } else if (errno != ENOENT || !(flags & O_CREAT)) {
 429         krb5_set_error_message(context, errno, N_("%s lstat(%s)", "file, error"),
 430                                operation, filename);
 431         return errno;
 432     }
 433
 434     fd = open(filename, flags, mode);
 435     if(fd < 0) {
 436         char buf[128];
 437         ret = errno;
 438         rk_strerror_r(ret, buf, sizeof(buf));
 439         krb5_set_error_message(context, ret, N_("%s open(%s): %s", "file, error"),
 440                                operation, filename, buf);
 441         return ret;
 442     }
 443     rk_cloexec(fd);
 444
 445     ret = fstat(fd, &sb2);
 446     if (ret < 0) {
 447         krb5_clear_error_message(context);
 448         return errno;
 449     }
 450
 451     if (!S_ISREG(sb2.st_mode)) {
 452         krb5_set_error_message(context, EPERM, N_("Refuses to open non files caches: FILE:%s", ""), filename);
 453         close(fd);
 454         return EPERM;
 455     }
 456
 457 #ifndef _WIN32
 458     if (sb1.st_dev && sb1.st_ino &&
 459         (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino)) {
 460         /*
 461          * Perhaps we raced with a rename().  To complain about
 462          * symlinks in that case would cause unnecessary concern, so
 463          * we check for that possibility and loop.  This has no
 464          * TOCTOU problems because we redo the open().  We could also
 465          * not do any of this checking if O_NOFOLLOW != 0...
 466          */
 467         close(fd);
 468         ret = lstat(filename, &sb3);
 469         if (ret || sb1.st_dev != sb2.st_dev ||
 470             sb3.st_dev != sb2.st_dev || sb3.st_ino != sb2.st_ino) {
 471             krb5_set_error_message(context, EPERM, N_("Refuses to open possible symlink for caches: FILE:%s", ""), filename);
 472             return EPERM;
 473         }
 474         if (--tries == 0) {
 475             krb5_set_error_message(context, EPERM, N_("Raced too many times with renames of FILE:%s", ""), filename);
 476             return EPERM;
 477         }
 478         goto again;
 479     }
 480 #endif
 481
 482     if (sb2.st_nlink != 1) {
 483         krb5_set_error_message(context, EPERM, N_("Refuses to open hardlinks for caches FILE:%s", ""), filename);
 484         close(fd);
 485         return EPERM;
 486     }
 487
 488     if (strict_checking) {
 489 #ifndef _WIN32
 490         /*
 491          * XXX WIN32: Needs to have ACL checking code!
 492          * st_mode comes out as 100666, and st_uid is no use.
 493          */
 494         /*
 495          * XXX Should probably add options to improve control over this
 496          * check.  We might want strict checking of everything except
 497          * this.
 498          */
 499         if (sb2.st_uid != geteuid()) {
 500             krb5_set_error_message(context, EPERM, N_("Refuses to open cache files not own by myself FILE:%s (owned by %d)", ""), filename, (int)sb2.st_uid);
 501             close(fd);
 502             return EPERM;
 503         }
 504         if ((sb2.st_mode & 077) != 0) {
 505             krb5_set_error_message(context, EPERM,
 506                                    N_("Refuses to open group/other readable files FILE:%s", ""), filename);
 507             close(fd);
 508             return EPERM;
 509         }
 510 #endif
 511     }
 512
 513     if((ret = fcc_lock(context, id, fd, exclusive)) != 0) {
 514         close(fd);
 515         return ret;
 516     }
 517     *fd_ret = fd;
 518     return 0;
 519 }
 520
 521 static krb5_error_code KRB5_CALLCONV
 522 fcc_initialize(krb5_context context,
 523                krb5_ccache id,
 524                krb5_principal primary_principal)
 525 {
 526     krb5_fcache *f = FCACHE(id);
 527     int ret = 0;
 528     int fd;
 529
 530     if (f == NULL)
 531         return krb5_einval(context, 2);
 532
 533     unlink (f->filename);
 534
 535     ret = fcc_open(context, id, "initialize", &fd, O_RDWR | O_CREAT | O_EXCL, 0600);
 536     if(ret)
 537         return ret;
 538     {
 539         krb5_storage *sp;
 540         sp = krb5_storage_emem();
 541         krb5_storage_set_eof_code(sp, KRB5_CC_END);
 542         if(context->fcache_vno != 0)
 543             f->version = context->fcache_vno;
 544         else
 545             f->version = KRB5_FCC_FVNO_4;
 546         ret |= krb5_store_int8(sp, 5);
 547         ret |= krb5_store_int8(sp, f->version);
 548         storage_set_flags(context, sp, f->version);
 549         if(f->version == KRB5_FCC_FVNO_4 && ret == 0) {
 550             /* V4 stuff */
 551             if (context->kdc_sec_offset) {
 552                 ret |= krb5_store_int16 (sp, 12); /* length */
 553                 ret |= krb5_store_int16 (sp, FCC_TAG_DELTATIME); /* Tag */
 554                 ret |= krb5_store_int16 (sp, 8); /* length of data */
 555                 ret |= krb5_store_int32 (sp, context->kdc_sec_offset);
 556                 ret |= krb5_store_int32 (sp, context->kdc_usec_offset);
 557             } else {
 558                 ret |= krb5_store_int16 (sp, 0);
 559             }
 560         }
 561         ret |= krb5_store_principal(sp, primary_principal);
 562
 563         ret |= write_storage(context, sp, fd);
 564
 565         krb5_storage_free(sp);
 566     }
 567     fcc_unlock(context, fd);
 568     if (close(fd) < 0)
 569         if (ret == 0) {
 570             char buf[128];
 571             ret = errno;
 572             rk_strerror_r(ret, buf, sizeof(buf));
 573             krb5_set_error_message(context, ret, N_("close %s: %s", ""),
 574                                    FILENAME(id), buf);
 575         }
 576     return ret;
 577 }
 578
 579 static krb5_error_code KRB5_CALLCONV
 580 fcc_close(krb5_context context,
 581           krb5_ccache id)
 582 {
 583     if (FCACHE(id) == NULL)
 584         return krb5_einval(context, 2);
 585
 586     free (FILENAME(id));
 587     krb5_data_free(&id->data);
 588     return 0;
 589 }
 590
 591 static krb5_error_code KRB5_CALLCONV
 592 fcc_destroy(krb5_context context,
 593             krb5_ccache id)
 594 {
 595     if (FCACHE(id) == NULL)
 596         return krb5_einval(context, 2);
 597
 598     _krb5_erase_file(context, FILENAME(id));
 599     return 0;
 600 }
 601
 602 static krb5_error_code KRB5_CALLCONV
 603 fcc_store_cred(krb5_context context,
 604                krb5_ccache id,
 605                krb5_creds *creds)
 606 {
 607     int ret;
 608     int fd;
 609
 610     ret = fcc_open(context, id, "store", &fd, O_WRONLY | O_APPEND, 0);
 611     if(ret)
 612         return ret;
 613     {
 614         krb5_storage *sp;
 615
 616         sp = krb5_storage_emem();
 617         krb5_storage_set_eof_code(sp, KRB5_CC_END);
 618         storage_set_flags(context, sp, FCACHE(id)->version);
 619         ret = krb5_store_creds(sp, creds);
 620         if (ret == 0)
 621             ret = write_storage(context, sp, fd);
 622         krb5_storage_free(sp);
 623     }
 624     fcc_unlock(context, fd);
 625     if (close(fd) < 0) {
 626         if (ret == 0) {
 627             char buf[128];
 628             rk_strerror_r(ret, buf, sizeof(buf));
 629             ret = errno;
 630             krb5_set_error_message(context, ret, N_("close %s: %s", ""),
 631                                    FILENAME(id), buf);
 632         }
 633     }
 634     return ret;
 635 }
 636
 637 static krb5_error_code
 638 init_fcc(krb5_context context,
 639          krb5_ccache id,
 640          const char *operation,
 641          krb5_storage **ret_sp,
 642          int *ret_fd,
 643          krb5_deltat *kdc_offset)
 644 {
 645     int fd;
 646     int8_t pvno, tag;
 647     krb5_storage *sp;
 648     krb5_error_code ret;
 649
 650     if (kdc_offset)
 651         *kdc_offset = 0;
 652
 653     ret = fcc_open(context, id, operation, &fd, O_RDONLY, 0);
 654     if(ret)
 655         return ret;
 656
 657     sp = krb5_storage_from_fd(fd);
 658     if(sp == NULL) {
 659         krb5_clear_error_message(context);
 660         ret = ENOMEM;
 661         goto out;
 662     }
 663     krb5_storage_set_eof_code(sp, KRB5_CC_END);
 664     ret = krb5_ret_int8(sp, &pvno);
 665     if (ret != 0) {
 666         if(ret == KRB5_CC_END) {
 667             ret = ENOENT;
 668             krb5_set_error_message(context, ret,
 669                                    N_("Empty credential cache file: %s", ""),
 670                                    FILENAME(id));
 671         } else
 672             krb5_set_error_message(context, ret, N_("Error reading pvno "
 673                                                     "in cache file: %s", ""),
 674                                    FILENAME(id));
 675         goto out;
 676     }
 677     if (pvno != 5) {
 678         ret = KRB5_CCACHE_BADVNO;
 679         krb5_set_error_message(context, ret, N_("Bad version number in credential "
 680                                                 "cache file: %s", ""),
 681                                FILENAME(id));
 682         goto out;
 683     }
 684     ret = krb5_ret_int8(sp, &tag); /* should not be host byte order */
 685     if (ret != 0) {
 686         ret = KRB5_CC_FORMAT;
 687         krb5_set_error_message(context, ret, "Error reading tag in "
 688                               "cache file: %s", FILENAME(id));
 689         goto out;
 690     }
 691     FCACHE(id)->version = tag;
 692     storage_set_flags(context, sp, FCACHE(id)->version);
 693     switch (tag) {
 694     case KRB5_FCC_FVNO_4: {
 695         int16_t length;
 696
 697         ret = krb5_ret_int16 (sp, &length);
 698         if(ret) {
 699             ret = KRB5_CC_FORMAT;
 700             krb5_set_error_message(context, ret,
 701                                    N_("Error reading tag length in "
 702                                       "cache file: %s", ""), FILENAME(id));
 703             goto out;
 704         }
 705         while(length > 0) {
 706             int16_t dtag, data_len;
 707             int i;
 708             int8_t dummy;
 709
 710             ret = krb5_ret_int16 (sp, &dtag);
 711             if(ret) {
 712                 ret = KRB5_CC_FORMAT;
 713                 krb5_set_error_message(context, ret, N_("Error reading dtag in "
 714                                                         "cache file: %s", ""),
 715                                        FILENAME(id));
 716                 goto out;
 717             }
 718             ret = krb5_ret_int16 (sp, &data_len);
 719             if(ret) {
 720                 ret = KRB5_CC_FORMAT;
 721                 krb5_set_error_message(context, ret,
 722                                        N_("Error reading dlength "
 723                                           "in cache file: %s",""),
 724                                        FILENAME(id));
 725                 goto out;
 726             }
 727             switch (dtag) {
 728             case FCC_TAG_DELTATIME : {
 729                 int32_t offset;
 730
 731                 ret = krb5_ret_int32 (sp, &offset);
 732                 ret |= krb5_ret_int32 (sp, &context->kdc_usec_offset);
 733                 if(ret) {
 734                     ret = KRB5_CC_FORMAT;
 735                     krb5_set_error_message(context, ret,
 736                                            N_("Error reading kdc_sec in "
 737                                               "cache file: %s", ""),
 738                                            FILENAME(id));
 739                     goto out;
 740                 }
 741                 context->kdc_sec_offset = offset;
 742                 if (kdc_offset)
 743                     *kdc_offset = offset;
 744                 break;
 745             }
 746             default :
 747                 for (i = 0; i < data_len; ++i) {
 748                     ret = krb5_ret_int8 (sp, &dummy);
 749                     if(ret) {
 750                         ret = KRB5_CC_FORMAT;
 751                         krb5_set_error_message(context, ret,
 752                                                N_("Error reading unknown "
 753                                                   "tag in cache file: %s", ""),
 754                                                FILENAME(id));
 755                         goto out;
 756                     }
 757                 }
 758                 break;
 759             }
 760             length -= 4 + data_len;
 761         }
 762         break;
 763     }
 764     case KRB5_FCC_FVNO_3:
 765     case KRB5_FCC_FVNO_2:
 766     case KRB5_FCC_FVNO_1:
 767         break;
 768     default :
 769         ret = KRB5_CCACHE_BADVNO;
 770         krb5_set_error_message(context, ret,
 771                                N_("Unknown version number (%d) in "
 772                                   "credential cache file: %s", ""),
 773                                (int)tag, FILENAME(id));
 774         goto out;
 775     }
 776     *ret_sp = sp;
 777     *ret_fd = fd;
 778
 779     return 0;
 780   out:
 781     if(sp != NULL)
 782         krb5_storage_free(sp);
 783     fcc_unlock(context, fd);
 784     close(fd);
 785     return ret;
 786 }
 787
 788 static krb5_error_code KRB5_CALLCONV
 789 fcc_get_principal(krb5_context context,
 790                   krb5_ccache id,
 791                   krb5_principal *principal)
 792 {
 793     krb5_error_code ret;
 794     int fd;
 795     krb5_storage *sp;
 796
 797     ret = init_fcc (context, id, "get-pricipal", &sp, &fd, NULL);
 798     if (ret)
 799         return ret;
 800     ret = krb5_ret_principal(sp, principal);
 801     if (ret)
 802         krb5_clear_error_message(context);
 803     krb5_storage_free(sp);
 804     fcc_unlock(context, fd);
 805     close(fd);
 806     return ret;
 807 }
 808
 809 static krb5_error_code KRB5_CALLCONV
 810 fcc_end_get (krb5_context context,
 811              krb5_ccache id,
 812              krb5_cc_cursor *cursor);
 813
 814 static krb5_error_code KRB5_CALLCONV
 815 fcc_get_first (krb5_context context,
 816                krb5_ccache id,
 817                krb5_cc_cursor *cursor)
 818 {
 819     krb5_error_code ret;
 820     krb5_principal principal;
 821
 822     if (FCACHE(id) == NULL)
 823         return krb5_einval(context, 2);
 824
 825     *cursor = malloc(sizeof(struct fcc_cursor));
 826     if (*cursor == NULL) {
 827         krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
 828         return ENOMEM;
 829     }
 830     memset(*cursor, 0, sizeof(struct fcc_cursor));
 831
 832     ret = init_fcc(context, id, "get-frist", &FCC_CURSOR(*cursor)->sp,
 833                    &FCC_CURSOR(*cursor)->fd, NULL);
 834     if (ret) {
 835         free(*cursor);
 836         *cursor = NULL;
 837         return ret;
 838     }
 839     ret = krb5_ret_principal (FCC_CURSOR(*cursor)->sp, &principal);
 840     if(ret) {
 841         krb5_clear_error_message(context);
 842         fcc_end_get(context, id, cursor);
 843         return ret;
 844     }
 845     krb5_free_principal (context, principal);
 846     fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
 847     return 0;
 848 }
 849
 850 static krb5_error_code KRB5_CALLCONV
 851 fcc_get_next (krb5_context context,
 852               krb5_ccache id,
 853               krb5_cc_cursor *cursor,
 854               krb5_creds *creds)
 855 {
 856     krb5_error_code ret;
 857
 858     if (FCACHE(id) == NULL)
 859         return krb5_einval(context, 2);
 860
 861     if (FCC_CURSOR(*cursor) == NULL)
 862         return krb5_einval(context, 3);
 863
 864     if((ret = fcc_lock(context, id, FCC_CURSOR(*cursor)->fd, FALSE)) != 0)
 865         return ret;
 866     FCC_CURSOR(*cursor)->cred_start = lseek(FCC_CURSOR(*cursor)->fd,
 867                                            0, SEEK_CUR);
 868
 869     ret = krb5_ret_creds(FCC_CURSOR(*cursor)->sp, creds);
 870     if (ret)
 871         krb5_clear_error_message(context);
 872
 873     FCC_CURSOR(*cursor)->cred_end = lseek(FCC_CURSOR(*cursor)->fd,
 874                                          0, SEEK_CUR);
 875
 876     fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
 877     return ret;
 878 }
 879
 880 static krb5_error_code KRB5_CALLCONV
 881 fcc_end_get (krb5_context context,
 882              krb5_ccache id,
 883              krb5_cc_cursor *cursor)
 884 {
 885
 886     if (FCACHE(id) == NULL)
 887         return krb5_einval(context, 2);
 888
 889     if (FCC_CURSOR(*cursor) == NULL)
 890         return krb5_einval(context, 3);
 891
 892     krb5_storage_free(FCC_CURSOR(*cursor)->sp);
 893     close (FCC_CURSOR(*cursor)->fd);
 894     free(*cursor);
 895     *cursor = NULL;
 896     return 0;
 897 }
 898
 899 static void KRB5_CALLCONV
 900 cred_delete(krb5_context context,
 901             krb5_ccache id,
 902             krb5_cc_cursor *cursor,
 903             krb5_creds *cred)
 904 {
 905     krb5_error_code ret;
 906     krb5_storage *sp;
 907     krb5_data orig_cred_data;
 908     unsigned char *cred_data_in_file = NULL;
 909     off_t new_cred_sz;
 910     struct stat sb1, sb2;
 911     int fd = -1;
 912     ssize_t bytes;
 913     krb5_const_realm srealm = krb5_principal_get_realm(context, cred->server);
 914
 915     /* This is best-effort code; if we lose track of errors here it's OK */
 916
 917     heim_assert(FCC_CURSOR(*cursor)->cred_start < FCC_CURSOR(*cursor)->cred_end,
 918                 "fcache internal error");
 919
 920     krb5_data_zero(&orig_cred_data);
 921
 922     sp = krb5_storage_emem();
 923     if (sp == NULL)
 924         return;
 925     krb5_storage_set_eof_code(sp, KRB5_CC_END);
 926     storage_set_flags(context, sp, FCACHE(id)->version);
 927
 928     /* Get a copy of what the cred should look like in the file; see below */
 929     ret = krb5_store_creds(sp, cred);
 930     if (ret)
 931         goto out;
 932
 933     ret = krb5_storage_to_data(sp, &orig_cred_data);
 934     if (ret)
 935         goto out;
 936     krb5_storage_free(sp);
 937
 938     cred_data_in_file = malloc(orig_cred_data.length);
 939     if (cred_data_in_file == NULL)
 940         goto out;
 941
 942     /*
 943      * Mark the cred expired; krb5_cc_retrieve_cred() callers should use
 944      * KRB5_TC_MATCH_TIMES, so this should be good enough...
 945      */
 946     cred->times.endtime = 0;
 947
 948     /* ...except for config creds because we don't check their endtimes */
 949     if (srealm && strcmp(srealm, "X-CACHECONF:") == 0) {
 950         ret = krb5_principal_set_realm(context, cred->server, "X-RMED-CONF:");
 951         if (ret)
 952             return;
 953     }
 954
 955     sp = krb5_storage_emem();
 956     if (sp == NULL)
 957         return;
 958     krb5_storage_set_eof_code(sp, KRB5_CC_END);
 959     storage_set_flags(context, sp, FCACHE(id)->version);
 960
 961     ret = krb5_store_creds(sp, cred);
 962
 963     /* The new cred must be the same size as the old cred */
 964     new_cred_sz = krb5_storage_seek(sp, 0, SEEK_END);
 965     if (new_cred_sz != orig_cred_data.length || new_cred_sz !=
 966         (FCC_CURSOR(*cursor)->cred_end - FCC_CURSOR(*cursor)->cred_start)) {
 967         /* XXX This really can't happen.  Assert like above? */
 968         krb5_set_error_message(context, EINVAL,
 969                                N_("Credential deletion failed on ccache "
 970                                   "FILE:%s: new credential size did not "
 971                                   "match old credential size", ""),
 972                                FILENAME(id));
 973         goto out;
 974     }
 975
 976     ret = fcc_open(context, id, "remove_cred", &fd, O_RDWR, 0);
 977     if (ret)
 978         goto out;
 979
 980     /*
 981      * Check that we're updating the same file where we got the
 982      * cred's offset, else we'd be corrupting a new ccache.
 983      */
 984     if (fstat(FCC_CURSOR(*cursor)->fd, &sb1) == -1 ||
 985         fstat(fd, &sb2) == -1)
 986         goto out;
 987     if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino)
 988         goto out;
 989
 990     /*
 991      * Make sure what we overwrite is what we expected.
 992      *
 993      * FIXME: We *really* need the ccache v4 tag for ccache ID.  This
 994      * check that we're only overwriting something that looks exactly
 995      * like what we want to is probably good enough in practice, but
 996      * it's not guaranteed to work.
 997      */
 998     if (lseek(fd, FCC_CURSOR(*cursor)->cred_start, SEEK_SET) == (off_t)-1)
 999         goto out;
1000     bytes = read(fd, cred_data_in_file, orig_cred_data.length);
1001     if (bytes != orig_cred_data.length)
1002         goto out;
1003     if (memcmp(orig_cred_data.data, cred_data_in_file, bytes) != 0)
1004         goto out;
1005     if (lseek(fd, FCC_CURSOR(*cursor)->cred_start, SEEK_SET) == (off_t)-1)
1006         goto out;
1007     ret = write_storage(context, sp, fd);
1008 out:
1009     if (fd > -1) {
1010         fcc_unlock(context, fd);
1011         if (close(fd) < 0 && ret == 0) {
1012             krb5_set_error_message(context, errno, N_("close %s", ""),
1013                                    FILENAME(id));
1014         }
1015     }
1016     krb5_data_free(&orig_cred_data);
1017     free(cred_data_in_file);
1018     krb5_storage_free(sp);
1019     return;
1020 }
1021
1022 static krb5_error_code KRB5_CALLCONV
1023 fcc_remove_cred(krb5_context context,
1024                 krb5_ccache id,
1025                 krb5_flags which,
1026                 krb5_creds *mcred)
1027 {
1028     krb5_error_code ret, ret2;
1029     krb5_cc_cursor cursor;
1030     krb5_creds found_cred;
1031
1032     if (FCACHE(id) == NULL)
1033         return krb5_einval(context, 2);
1034
1035     ret = krb5_cc_start_seq_get(context, id, &cursor);
1036     if (ret)
1037         return ret;
1038     while ((ret = krb5_cc_next_cred(context, id, &cursor, &found_cred)) == 0) {
1039         if (!krb5_compare_creds(context, which, mcred, &found_cred)) {
1040             krb5_free_cred_contents(context, &found_cred);
1041             continue;
1042         }
1043         cred_delete(context, id, &cursor, &found_cred);
1044         krb5_free_cred_contents(context, &found_cred);
1045     }
1046     ret2 = krb5_cc_end_seq_get(context, id, &cursor);
1047     if (ret == 0)
1048         return ret2;
1049     if (ret == KRB5_CC_END)
1050         return 0;
1051     return ret;
1052 }
1053
1054 static krb5_error_code KRB5_CALLCONV
1055 fcc_set_flags(krb5_context context,
1056               krb5_ccache id,
1057               krb5_flags flags)
1058 {
1059     if (FCACHE(id) == NULL)
1060         return krb5_einval(context, 2);
1061
1062     return 0; /* XXX */
1063 }
1064
1065 static int KRB5_CALLCONV
1066 fcc_get_version(krb5_context context,
1067                 krb5_ccache id)
1068 {
1069     if (FCACHE(id) == NULL)
1070         return -1;
1071
1072     return FCACHE(id)->version;
1073 }
1074
1075 struct fcache_iter {
1076     int first;
1077 };
1078
1079 static krb5_error_code KRB5_CALLCONV
1080 fcc_get_cache_first(krb5_context context, krb5_cc_cursor *cursor)
1081 {
1082     struct fcache_iter *iter;
1083
1084     iter = calloc(1, sizeof(*iter));
1085     if (iter == NULL) {
1086         krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
1087         return ENOMEM;
1088     }
1089     iter->first = 1;
1090     *cursor = iter;
1091     return 0;
1092 }
1093
1094 static krb5_error_code KRB5_CALLCONV
1095 fcc_get_cache_next(krb5_context context, krb5_cc_cursor cursor, krb5_ccache *id)
1096 {
1097     struct fcache_iter *iter = cursor;
1098     krb5_error_code ret;
1099     const char *fn, *cc_type;
1100     krb5_ccache cc;
1101
1102     if (iter == NULL)
1103         return krb5_einval(context, 2);
1104
1105     if (!iter->first) {
1106         krb5_clear_error_message(context);
1107         return KRB5_CC_END;
1108     }
1109     iter->first = 0;
1110
1111     /*
1112      * Note: do not allow krb5_cc_default_name() to recurse via
1113      * krb5_cc_cache_match().
1114      * Note that context->default_cc_name will be NULL even though
1115      * KRB5CCNAME is set in the environment if
1116      * krb5_cc_set_default_name() hasn't
1117      */
1118     fn = krb5_cc_default_name(context);
1119     ret = krb5_cc_resolve(context, fn, &cc);
1120     if (ret != 0)
1121         return ret;
1122     cc_type = krb5_cc_get_type(context, cc);
1123     if (strcmp(cc_type, "FILE") != 0) {
1124         krb5_cc_close(context, cc);
1125         return KRB5_CC_END;
1126     }
1127
1128     *id = cc;
1129
1130     return 0;
1131 }
1132
1133 static krb5_error_code KRB5_CALLCONV
1134 fcc_end_cache_get(krb5_context context, krb5_cc_cursor cursor)
1135 {
1136     struct fcache_iter *iter = cursor;
1137
1138     if (iter == NULL)
1139         return krb5_einval(context, 2);
1140
1141     free(iter);
1142     return 0;
1143 }
1144
1145 static krb5_error_code KRB5_CALLCONV
1146 fcc_move(krb5_context context, krb5_ccache from, krb5_ccache to)
1147 {
1148     krb5_error_code ret = 0;
1149
1150     ret = rk_rename(FILENAME(from), FILENAME(to));
1151
1152     if (ret && errno != EXDEV) {
1153         char buf[128];
1154         ret = errno;
1155         rk_strerror_r(ret, buf, sizeof(buf));
1156         krb5_set_error_message(context, ret,
1157                                N_("Rename of file from %s "
1158                                   "to %s failed: %s", ""),
1159                                FILENAME(from), FILENAME(to), buf);
1160         return ret;
1161     } else if (ret && errno == EXDEV) {
1162         /* make a copy and delete the orignal */
1163         krb5_ssize_t sz1, sz2;
1164         int fd1, fd2;
1165         char buf[BUFSIZ];
1166
1167         ret = fcc_open(context, from, "move/from", &fd1, O_RDONLY, 0);
1168         if(ret)
1169             return ret;
1170
1171         unlink(FILENAME(to));
1172
1173         ret = fcc_open(context, to, "move/to", &fd2,
1174                        O_WRONLY | O_CREAT | O_EXCL, 0600);
1175         if(ret)
1176             goto out1;
1177
1178         while((sz1 = read(fd1, buf, sizeof(buf))) > 0) {
1179             sz2 = write(fd2, buf, sz1);
1180             if (sz1 != sz2) {
1181                 ret = EIO;
1182                 krb5_set_error_message(context, ret,
1183                                        N_("Failed to write data from one file "
1184                                           "credential cache to the other", ""));
1185                 goto out2;
1186             }
1187         }
1188         if (sz1 < 0) {
1189             ret = EIO;
1190             krb5_set_error_message(context, ret,
1191                                    N_("Failed to read data from one file "
1192                                       "credential cache to the other", ""));
1193             goto out2;
1194         }
1195     out2:
1196         fcc_unlock(context, fd2);
1197         close(fd2);
1198
1199     out1:
1200         fcc_unlock(context, fd1);
1201         close(fd1);
1202
1203         _krb5_erase_file(context, FILENAME(from));
1204
1205         if (ret) {
1206             _krb5_erase_file(context, FILENAME(to));
1207             return ret;
1208         }
1209     }
1210
1211     /* make sure ->version is uptodate */
1212     {
1213         krb5_storage *sp;
1214         int fd;
1215         if ((ret = init_fcc (context, to, "move", &sp, &fd, NULL)) == 0) {
1216             if (sp)
1217                 krb5_storage_free(sp);
1218             fcc_unlock(context, fd);
1219             close(fd);
1220         }
1221     }
1222
1223     fcc_close(context, from);
1224
1225     return ret;
1226 }
1227
1228 static krb5_error_code KRB5_CALLCONV
1229 fcc_get_default_name(krb5_context context, char **str)
1230 {
1231     return _krb5_expand_default_cc_name(context,
1232                                         KRB5_DEFAULT_CCNAME_FILE,
1233                                         str);
1234 }
1235
1236 static krb5_error_code KRB5_CALLCONV
1237 fcc_lastchange(krb5_context context, krb5_ccache id, krb5_timestamp *mtime)
1238 {
1239     krb5_error_code ret;
1240     struct stat sb;
1241     int fd;
1242
1243     ret = fcc_open(context, id, "lastchange", &fd, O_RDONLY, 0);
1244     if(ret)
1245         return ret;
1246     ret = fstat(fd, &sb);
1247     close(fd);
1248     if (ret) {
1249         ret = errno;
1250         krb5_set_error_message(context, ret, N_("Failed to stat cache file", ""));
1251         return ret;
1252     }
1253     *mtime = sb.st_mtime;
1254     return 0;
1255 }
1256
1257 static krb5_error_code KRB5_CALLCONV
1258 fcc_set_kdc_offset(krb5_context context, krb5_ccache id, krb5_deltat kdc_offset)
1259 {
1260     return 0;
1261 }
1262
1263 static krb5_error_code KRB5_CALLCONV
1264 fcc_get_kdc_offset(krb5_context context, krb5_ccache id, krb5_deltat *kdc_offset)
1265 {
1266     krb5_error_code ret;
1267     krb5_storage *sp = NULL;
1268     int fd;
1269     ret = init_fcc(context, id, "get-kdc-offset", &sp, &fd, kdc_offset);
1270     if (sp)
1271         krb5_storage_free(sp);
1272     fcc_unlock(context, fd);
1273     close(fd);
1274
1275     return ret;
1276 }
1277
1278
1279 /**
1280  * Variable containing the FILE based credential cache implemention.
1281  *
1282  * @ingroup krb5_ccache
1283  */
1284
1285 KRB5_LIB_VARIABLE const krb5_cc_ops krb5_fcc_ops = {
1286     KRB5_CC_OPS_VERSION,
1287     "FILE",
1288     fcc_get_name,
1289     fcc_resolve,
1290     fcc_gen_new,
1291     fcc_initialize,
1292     fcc_destroy,
1293     fcc_close,
1294     fcc_store_cred,
1295     NULL, /* fcc_retrieve */
1296     fcc_get_principal,
1297     fcc_get_first,
1298     fcc_get_next,
1299     fcc_end_get,
1300     fcc_remove_cred,
1301     fcc_set_flags,
1302     fcc_get_version,
1303     fcc_get_cache_first,
1304     fcc_get_cache_next,
1305     fcc_end_cache_get,
1306     fcc_move,
1307     fcc_get_default_name,
1308     NULL,
1309     fcc_lastchange,
1310     fcc_set_kdc_offset,
1311     fcc_get_kdc_offset
1312 };