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);
 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, &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, sb3;
 400     int strict_checking;
 401     int fd;
 402     size_t tries = 3;
 403
 404     *fd_ret = -1;
 405
 406     if (FCACHE(id) == NULL)
 407         return krb5_einval(context, 2);
 408
 409     filename = FILENAME(id);
 410
 411     strict_checking = (flags & O_CREAT) == 0 &&
 412         (context->flags & KRB5_CTX_F_FCACHE_STRICT_CHECKING) != 0;
 413
 414 again:
 415     if (strict_checking) {
 416         ret = lstat(filename, &sb1);
 417         if (ret < 0) {
 418             krb5_set_error_message(context, ret, N_("%s lstat(%s)", "file, error"),
 419                                    operation, filename);
 420             return errno;
 421         }
 422     }
 423
 424     if (!S_ISREG(sb1.st_mode)) {
 425         krb5_set_error_message(context, EPERM
 426                         N_("Refuses to open symlinks for "
 427                            "caches FILE:%s", ""), filename);
 428         return EPERM;
 429     }
 430
 431     fd = open(filename, flags, mode);
 432     if(fd < 0) {
 433         char buf[128];
 434         ret = errno;
 435         rk_strerror_r(ret, buf, sizeof(buf));
 436         krb5_set_error_message(context, ret, N_("%s open(%s): %s", "file, error"),
 437                                operation, filename, buf);
 438         return ret;
 439     }
 440     rk_cloexec(fd);
 441
 442     if (strict_checking) {
 443
 444         ret = fstat(fd, &sb2);
 445         if (ret < 0) {
 446             krb5_clear_error_message(context);
 447             return errno;
 448         }
 449
 450         if (!S_ISREG(sb2.st_mode)) {
 451             krb5_set_error_message(context, EPERM, N_("Refuses to open non files caches: FILE:%s", ""), filename);
 452             close(fd);
 453             return EPERM;
 454         }
 455
 456 #ifndef _WIN32
 457         /* All of the following could be #ifndef O_NOFOLLOW, FYI */
 458         if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino) {
 459             /*
 460              * Perhaps we raced with a rename().  To complain about
 461              * symlinks in that case would cause unnecessary concern, so
 462              * we check for that possibility and loop.  This has no
 463              * TOCTOU problems because we redo the open() (and if we
 464              * have O_NOFOLLOW we could even avoid that too).
 465              */
 466             close(fd);
 467             ret = lstat(filename, &sb3);
 468             if (ret || sb1.st_dev != sb2.st_dev ||
 469                  sb3.st_dev != sb2.st_dev || sb3.st_ino != sb2.st_ino) {
 470                 krb5_set_error_message(context, EPERM, N_("Refuses to open possible symlink for caches: FILE:%s", ""), filename);
 471                 return EPERM;
 472             }
 473             if (--tries == 0) {
 474                 krb5_set_error_message(context, EPERM, N_("Raced too many times with renames of FILE:%s", ""), filename);
 475                 return EPERM;
 476             }
 477             goto again;
 478         }
 479 #endif
 480
 481         if (sb2.st_nlink != 1) {
 482             krb5_set_error_message(context, EPERM, N_("Refuses to open hardlinks for caches FILE:%s", ""), filename);
 483             close(fd);
 484             return EPERM;
 485         }
 486 #ifndef _WIN32
 487         /*
 488          * XXX Should probably add options to improve control over this
 489          * check.  We might want strict checking of everything except
 490          * this, and we might want st_uid == getuid() || st_uid == geteuid()
 491          * to be OK.
 492          */
 493         if (sb2.st_uid != getuid()) {
 494             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);
 495             close(fd);
 496             return EPERM;
 497         }
 498         if ((sb2.st_mode & 077) != 0) {
 499             krb5_set_error_message(context, EPERM,
 500                                    N_("Refuses to open group/other readable files FILE:%s", ""), filename);
 501             close(fd);
 502             return EPERM;
 503         }
 504 #endif
 505     }
 506
 507     if((ret = fcc_lock(context, id, fd, exclusive)) != 0) {
 508         close(fd);
 509         return ret;
 510     }
 511     *fd_ret = fd;
 512     return 0;
 513 }
 514
 515 static krb5_error_code KRB5_CALLCONV
 516 fcc_initialize(krb5_context context,
 517                krb5_ccache id,
 518                krb5_principal primary_principal)
 519 {
 520     krb5_fcache *f = FCACHE(id);
 521     int ret = 0;
 522     int fd;
 523
 524     if (f == NULL)
 525         return krb5_einval(context, 2);
 526
 527     unlink (f->filename);
 528
 529     ret = fcc_open(context, id, "initialize", &fd, O_RDWR | O_CREAT | O_EXCL | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0600);
 530     if(ret)
 531         return ret;
 532     {
 533         krb5_storage *sp;
 534         sp = krb5_storage_emem();
 535         krb5_storage_set_eof_code(sp, KRB5_CC_END);
 536         if(context->fcache_vno != 0)
 537             f->version = context->fcache_vno;
 538         else
 539             f->version = KRB5_FCC_FVNO_4;
 540         ret |= krb5_store_int8(sp, 5);
 541         ret |= krb5_store_int8(sp, f->version);
 542         storage_set_flags(context, sp, f->version);
 543         if(f->version == KRB5_FCC_FVNO_4 && ret == 0) {
 544             /* V4 stuff */
 545             if (context->kdc_sec_offset) {
 546                 ret |= krb5_store_int16 (sp, 12); /* length */
 547                 ret |= krb5_store_int16 (sp, FCC_TAG_DELTATIME); /* Tag */
 548                 ret |= krb5_store_int16 (sp, 8); /* length of data */
 549                 ret |= krb5_store_int32 (sp, context->kdc_sec_offset);
 550                 ret |= krb5_store_int32 (sp, context->kdc_usec_offset);
 551             } else {
 552                 ret |= krb5_store_int16 (sp, 0);
 553             }
 554         }
 555         ret |= krb5_store_principal(sp, primary_principal);
 556
 557         ret |= write_storage(context, sp, fd);
 558
 559         krb5_storage_free(sp);
 560     }
 561     fcc_unlock(context, fd);
 562     if (close(fd) < 0)
 563         if (ret == 0) {
 564             char buf[128];
 565             ret = errno;
 566             rk_strerror_r(ret, buf, sizeof(buf));
 567             krb5_set_error_message (context, ret, N_("close %s: %s", ""),
 568                                     FILENAME(id), buf);
 569         }
 570     return ret;
 571 }
 572
 573 static krb5_error_code KRB5_CALLCONV
 574 fcc_close(krb5_context context,
 575           krb5_ccache id)
 576 {
 577     if (FCACHE(id) == NULL)
 578         return krb5_einval(context, 2);
 579
 580     free (FILENAME(id));
 581     krb5_data_free(&id->data);
 582     return 0;
 583 }
 584
 585 static krb5_error_code KRB5_CALLCONV
 586 fcc_destroy(krb5_context context,
 587             krb5_ccache id)
 588 {
 589     if (FCACHE(id) == NULL)
 590         return krb5_einval(context, 2);
 591
 592     _krb5_erase_file(context, FILENAME(id));
 593     return 0;
 594 }
 595
 596 static krb5_error_code KRB5_CALLCONV
 597 fcc_store_cred(krb5_context context,
 598                krb5_ccache id,
 599                krb5_creds *creds)
 600 {
 601     int ret;
 602     int fd;
 603
 604     ret = fcc_open(context, id, "store", &fd, O_WRONLY | O_APPEND | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0);
 605     if(ret)
 606         return ret;
 607     {
 608         krb5_storage *sp;
 609
 610         sp = krb5_storage_emem();
 611         krb5_storage_set_eof_code(sp, KRB5_CC_END);
 612         storage_set_flags(context, sp, FCACHE(id)->version);
 613         if (!krb5_config_get_bool_default(context, NULL, TRUE,
 614                                           "libdefaults",
 615                                           "fcc-mit-ticketflags",
 616                                           NULL))
 617             krb5_storage_set_flags(sp, KRB5_STORAGE_CREDS_FLAGS_WRONG_BITORDER);
 618         ret = krb5_store_creds(sp, creds);
 619         if (ret == 0)
 620             ret = write_storage(context, sp, fd);
 621         krb5_storage_free(sp);
 622     }
 623     fcc_unlock(context, fd);
 624     if (close(fd) < 0) {
 625         if (ret == 0) {
 626             char buf[128];
 627             rk_strerror_r(ret, buf, sizeof(buf));
 628             ret = errno;
 629             krb5_set_error_message (context, ret, N_("close %s: %s", ""),
 630                                     FILENAME(id), buf);
 631         }
 632     }
 633     return ret;
 634 }
 635
 636 static krb5_error_code
 637 init_fcc(krb5_context context,
 638          krb5_ccache id,
 639          const char *operation,
 640          krb5_storage **ret_sp,
 641          int *ret_fd,
 642          krb5_deltat *kdc_offset)
 643 {
 644     int fd;
 645     int8_t pvno, tag;
 646     krb5_storage *sp;
 647     krb5_error_code ret;
 648
 649     if (kdc_offset)
 650         *kdc_offset = 0;
 651
 652     ret = fcc_open(context, id, operation, &fd, O_RDONLY | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0);
 653     if(ret)
 654         return ret;
 655
 656     sp = krb5_storage_from_fd(fd);
 657     if(sp == NULL) {
 658         krb5_clear_error_message(context);
 659         ret = ENOMEM;
 660         goto out;
 661     }
 662     krb5_storage_set_eof_code(sp, KRB5_CC_END);
 663     ret = krb5_ret_int8(sp, &pvno);
 664     if(ret != 0) {
 665         if(ret == KRB5_CC_END) {
 666             ret = ENOENT;
 667             krb5_set_error_message(context, ret,
 668                                    N_("Empty credential cache file: %s", ""),
 669                                    FILENAME(id));
 670         } else
 671             krb5_set_error_message(context, ret, N_("Error reading pvno "
 672                                                     "in cache file: %s", ""),
 673                                    FILENAME(id));
 674         goto out;
 675     }
 676     if(pvno != 5) {
 677         ret = KRB5_CCACHE_BADVNO;
 678         krb5_set_error_message(context, ret, N_("Bad version number in credential "
 679                                                 "cache file: %s", ""),
 680                                FILENAME(id));
 681         goto out;
 682     }
 683     ret = krb5_ret_int8(sp, &tag); /* should not be host byte order */
 684     if(ret != 0) {
 685         ret = KRB5_CC_FORMAT;
 686         krb5_set_error_message(context, ret, "Error reading tag in "
 687                               "cache file: %s", FILENAME(id));
 688         goto out;
 689     }
 690     FCACHE(id)->version = tag;
 691     storage_set_flags(context, sp, FCACHE(id)->version);
 692     switch (tag) {
 693     case KRB5_FCC_FVNO_4: {
 694         int16_t length;
 695
 696         ret = krb5_ret_int16 (sp, &length);
 697         if(ret) {
 698             ret = KRB5_CC_FORMAT;
 699             krb5_set_error_message(context, ret,
 700                                    N_("Error reading tag length in "
 701                                       "cache file: %s", ""), FILENAME(id));
 702             goto out;
 703         }
 704         while(length > 0) {
 705             int16_t dtag, data_len;
 706             int i;
 707             int8_t dummy;
 708
 709             ret = krb5_ret_int16 (sp, &dtag);
 710             if(ret) {
 711                 ret = KRB5_CC_FORMAT;
 712                 krb5_set_error_message(context, ret, N_("Error reading dtag in "
 713                                                         "cache file: %s", ""),
 714                                        FILENAME(id));
 715                 goto out;
 716             }
 717             ret = krb5_ret_int16 (sp, &data_len);
 718             if(ret) {
 719                 ret = KRB5_CC_FORMAT;
 720                 krb5_set_error_message(context, ret,
 721                                        N_("Error reading dlength "
 722                                           "in cache file: %s",""),
 723                                        FILENAME(id));
 724                 goto out;
 725             }
 726             switch (dtag) {
 727             case FCC_TAG_DELTATIME : {
 728                 int32_t offset;
 729
 730                 ret = krb5_ret_int32 (sp, &offset);
 731                 ret |= krb5_ret_int32 (sp, &context->kdc_usec_offset);
 732                 if(ret) {
 733                     ret = KRB5_CC_FORMAT;
 734                     krb5_set_error_message(context, ret,
 735                                            N_("Error reading kdc_sec in "
 736                                               "cache file: %s", ""),
 737                                            FILENAME(id));
 738                     goto out;
 739                 }
 740                 context->kdc_sec_offset = offset;
 741                 if (kdc_offset)
 742                     *kdc_offset = offset;
 743                 break;
 744             }
 745             default :
 746                 for (i = 0; i < data_len; ++i) {
 747                     ret = krb5_ret_int8 (sp, &dummy);
 748                     if(ret) {
 749                         ret = KRB5_CC_FORMAT;
 750                         krb5_set_error_message(context, ret,
 751                                                N_("Error reading unknown "
 752                                                   "tag in cache file: %s", ""),
 753                                                FILENAME(id));
 754                         goto out;
 755                     }
 756                 }
 757                 break;
 758             }
 759             length -= 4 + data_len;
 760         }
 761         break;
 762     }
 763     case KRB5_FCC_FVNO_3:
 764     case KRB5_FCC_FVNO_2:
 765     case KRB5_FCC_FVNO_1:
 766         break;
 767     default :
 768         ret = KRB5_CCACHE_BADVNO;
 769         krb5_set_error_message(context, ret,
 770                                N_("Unknown version number (%d) in "
 771                                   "credential cache file: %s", ""),
 772                                (int)tag, FILENAME(id));
 773         goto out;
 774     }
 775     *ret_sp = sp;
 776     *ret_fd = fd;
 777
 778     return 0;
 779   out:
 780     if(sp != NULL)
 781         krb5_storage_free(sp);
 782     fcc_unlock(context, fd);
 783     close(fd);
 784     return ret;
 785 }
 786
 787 static krb5_error_code KRB5_CALLCONV
 788 fcc_get_principal(krb5_context context,
 789                   krb5_ccache id,
 790                   krb5_principal *principal)
 791 {
 792     krb5_error_code ret;
 793     int fd;
 794     krb5_storage *sp;
 795
 796     ret = init_fcc (context, id, "get-pricipal", &sp, &fd, NULL);
 797     if (ret)
 798         return ret;
 799     ret = krb5_ret_principal(sp, principal);
 800     if (ret)
 801         krb5_clear_error_message(context);
 802     krb5_storage_free(sp);
 803     fcc_unlock(context, fd);
 804     close(fd);
 805     return ret;
 806 }
 807
 808 static krb5_error_code KRB5_CALLCONV
 809 fcc_end_get (krb5_context context,
 810              krb5_ccache id,
 811              krb5_cc_cursor *cursor);
 812
 813 static krb5_error_code KRB5_CALLCONV
 814 fcc_get_first (krb5_context context,
 815                krb5_ccache id,
 816                krb5_cc_cursor *cursor)
 817 {
 818     krb5_error_code ret;
 819     krb5_principal principal;
 820
 821     if (FCACHE(id) == NULL)
 822         return krb5_einval(context, 2);
 823
 824     *cursor = malloc(sizeof(struct fcc_cursor));
 825     if (*cursor == NULL) {
 826         krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
 827         return ENOMEM;
 828     }
 829     memset(*cursor, 0, sizeof(struct fcc_cursor));
 830
 831     ret = init_fcc(context, id, "get-frist", &FCC_CURSOR(*cursor)->sp,
 832                    &FCC_CURSOR(*cursor)->fd, NULL);
 833     if (ret) {
 834         free(*cursor);
 835         *cursor = NULL;
 836         return ret;
 837     }
 838     ret = krb5_ret_principal (FCC_CURSOR(*cursor)->sp, &principal);
 839     if(ret) {
 840         krb5_clear_error_message(context);
 841         fcc_end_get(context, id, cursor);
 842         return ret;
 843     }
 844     krb5_free_principal (context, principal);
 845     fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
 846     return 0;
 847 }
 848
 849 static krb5_error_code KRB5_CALLCONV
 850 fcc_get_next (krb5_context context,
 851               krb5_ccache id,
 852               krb5_cc_cursor *cursor,
 853               krb5_creds *creds)
 854 {
 855     krb5_error_code ret;
 856
 857     if (FCACHE(id) == NULL)
 858         return krb5_einval(context, 2);
 859
 860     if (FCC_CURSOR(*cursor) == NULL)
 861         return krb5_einval(context, 3);
 862
 863     if((ret = fcc_lock(context, id, FCC_CURSOR(*cursor)->fd, FALSE)) != 0)
 864         return ret;
 865     FCC_CURSOR(*cursor)->cred_start = lseek(FCC_CURSOR(*cursor)->fd,
 866                                            0, SEEK_CUR);
 867
 868     ret = krb5_ret_creds(FCC_CURSOR(*cursor)->sp, creds);
 869     if (ret)
 870         krb5_clear_error_message(context);
 871
 872     FCC_CURSOR(*cursor)->cred_end = lseek(FCC_CURSOR(*cursor)->fd,
 873                                          0, SEEK_CUR);
 874
 875     fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
 876     return ret;
 877 }
 878
 879 static krb5_error_code KRB5_CALLCONV
 880 fcc_end_get (krb5_context context,
 881              krb5_ccache id,
 882              krb5_cc_cursor *cursor)
 883 {
 884
 885     if (FCACHE(id) == NULL)
 886         return krb5_einval(context, 2);
 887
 888     if (FCC_CURSOR(*cursor) == NULL)
 889         return krb5_einval(context, 3);
 890
 891     krb5_storage_free(FCC_CURSOR(*cursor)->sp);
 892     close (FCC_CURSOR(*cursor)->fd);
 893     free(*cursor);
 894     *cursor = NULL;
 895     return 0;
 896 }
 897
 898 static void KRB5_CALLCONV
 899 cred_delete(krb5_context context,
 900             krb5_ccache id,
 901             krb5_cc_cursor *cursor,
 902             krb5_creds *cred)
 903 {
 904     krb5_error_code ret;
 905     krb5_storage *sp;
 906     krb5_data orig_cred_data;
 907     unsigned char *cred_data_in_file = NULL;
 908     off_t new_cred_sz;
 909     struct stat sb1, sb2;
 910     int fd = -1;
 911     size_t bytes;
 912     krb5_flags flags = 0;
 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     if (!krb5_config_get_bool_default(context, NULL, TRUE,
 922                                       "libdefaults",
 923                                       "fcc-mit-ticketflags",
 924                                       NULL))
 925         flags = KRB5_STORAGE_CREDS_FLAGS_WRONG_BITORDER;
 926
 927     sp = krb5_storage_emem();
 928     if (sp == NULL)
 929         return;
 930     krb5_storage_set_eof_code(sp, KRB5_CC_END);
 931     storage_set_flags(context, sp, FCACHE(id)->version);
 932     if (flags)
 933         krb5_storage_set_flags(sp, KRB5_STORAGE_CREDS_FLAGS_WRONG_BITORDER);
 934
 935     /* Get a copy of what the cred should look like in the file; see below */
 936     ret = krb5_store_creds(sp, cred);
 937     if (ret)
 938         goto out;
 939
 940     ret = krb5_storage_to_data(sp, &orig_cred_data);
 941     if (ret)
 942         goto out;
 943     krb5_storage_free(sp);
 944
 945     cred_data_in_file = malloc(orig_cred_data.length);
 946     if (cred_data_in_file == NULL)
 947         goto out;
 948
 949     /*
 950      * Mark the cred expired; krb5_cc_retrieve_cred() callers should use
 951      * KRB5_TC_MATCH_TIMES, so this should be good enough...
 952      */
 953     cred->times.endtime = 0;
 954
 955     /* ...except for config creds because we don't check their endtimes */
 956     if (srealm && strcmp(srealm, "X-CACHECONF:") == 0) {
 957         ret = krb5_principal_set_realm(context, cred->server, "X-RMED-CONF:");
 958         if (ret)
 959             return;
 960     }
 961
 962     sp = krb5_storage_emem();
 963     if (sp == NULL)
 964         return;
 965     krb5_storage_set_eof_code(sp, KRB5_CC_END);
 966     storage_set_flags(context, sp, FCACHE(id)->version);
 967     if (flags)
 968         krb5_storage_set_flags(sp, KRB5_STORAGE_CREDS_FLAGS_WRONG_BITORDER);
 969
 970     ret = krb5_store_creds(sp, cred);
 971
 972     /* The new cred must be the same size as the old cred */
 973     new_cred_sz = krb5_storage_seek(sp, 0, SEEK_END);
 974     if (new_cred_sz != orig_cred_data.length || new_cred_sz !=
 975         (FCC_CURSOR(*cursor)->cred_end - FCC_CURSOR(*cursor)->cred_start)) {
 976         /* XXX This really can't happen.  Assert like above? */
 977         krb5_set_error_message(context, EINVAL,
 978                                N_("Credential deletion failed on ccache "
 979                                   "FILE:%s: new credential size did not "
 980                                   "match old credential size", ""),
 981                                FILENAME(id));
 982         goto out;
 983     }
 984
 985     ret = fcc_open(context, id, "remove_cred", &fd,
 986                    O_RDWR | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0);
 987     if (ret)
 988         goto out;
 989
 990     /*
 991      * Check that we're updating the same file where we got the
 992      * cred's offset, else we'd be corrupting a new ccache.
 993      */
 994     if (fstat(FCC_CURSOR(*cursor)->fd, &sb1) == -1 ||
 995         fstat(fd, &sb2) == -1)
 996         goto out;
 997     if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino)
 998         goto out;
 999
1000     /*
1001      * Make sure what we overwrite is what we expected.
1002      *
1003      * FIXME: We *really* need the ccache v4 tag for ccache ID.  This
1004      * check that we're only overwriting something that looks exactly
1005      * like what we want to is probably good enough in practice, but
1006      * it's not guaranteed to work.
1007      */
1008     if (lseek(fd, FCC_CURSOR(*cursor)->cred_start, SEEK_SET) == (off_t)-1)
1009         goto out;
1010     bytes = read(fd, cred_data_in_file, orig_cred_data.length);
1011     if (bytes != orig_cred_data.length)
1012         goto out;
1013     if (memcmp(orig_cred_data.data, cred_data_in_file, bytes) != 0)
1014         goto out;
1015     if (lseek(fd, FCC_CURSOR(*cursor)->cred_start, SEEK_SET) == (off_t)-1)
1016         goto out;
1017     ret = write_storage(context, sp, fd);
1018 out:
1019     if (fd > -1) {
1020         fcc_unlock(context, fd);
1021         if (close(fd) < 0 && ret == 0) {
1022             char buf[128];
1023
1024             /* This error might be useful */
1025             rk_strerror_r(ret, buf, sizeof(buf));
1026             ret = errno;
1027             krb5_set_error_message(context, ret, N_("close %s: %s", ""),
1028                                    FILENAME(id), buf);
1029         }
1030     }
1031     krb5_data_free(&orig_cred_data);
1032     free(cred_data_in_file);
1033     krb5_storage_free(sp);
1034     return;
1035 }
1036
1037 static krb5_error_code KRB5_CALLCONV
1038 fcc_remove_cred(krb5_context context,
1039                 krb5_ccache id,
1040                 krb5_flags which,
1041                 krb5_creds *mcred)
1042 {
1043     krb5_error_code ret, ret2;
1044     krb5_cc_cursor cursor;
1045     krb5_creds found_cred;
1046
1047     if (FCACHE(id) == NULL)
1048         return krb5_einval(context, 2);
1049
1050     ret = krb5_cc_start_seq_get(context, id, &cursor);
1051     if (ret)
1052         return ret;
1053     while ((ret = krb5_cc_next_cred(context, id, &cursor, &found_cred)) == 0) {
1054         if (!krb5_compare_creds(context, which, mcred, &found_cred))
1055             continue;
1056         cred_delete(context, id, &cursor, &found_cred);
1057         krb5_free_cred_contents(context, &found_cred);
1058     }
1059     ret2 = krb5_cc_end_seq_get(context, id, &cursor);
1060     if (ret == 0)
1061         return ret2;
1062     if (ret == KRB5_CC_END)
1063         return 0;
1064     return ret;
1065 }
1066
1067 static krb5_error_code KRB5_CALLCONV
1068 fcc_set_flags(krb5_context context,
1069               krb5_ccache id,
1070               krb5_flags flags)
1071 {
1072     if (FCACHE(id) == NULL)
1073         return krb5_einval(context, 2);
1074
1075     return 0; /* XXX */
1076 }
1077
1078 static int KRB5_CALLCONV
1079 fcc_get_version(krb5_context context,
1080                 krb5_ccache id)
1081 {
1082     if (FCACHE(id) == NULL)
1083         return -1;
1084
1085     return FCACHE(id)->version;
1086 }
1087
1088 struct fcache_iter {
1089     int first;
1090 };
1091
1092 static krb5_error_code KRB5_CALLCONV
1093 fcc_get_cache_first(krb5_context context, krb5_cc_cursor *cursor)
1094 {
1095     struct fcache_iter *iter;
1096
1097     iter = calloc(1, sizeof(*iter));
1098     if (iter == NULL) {
1099         krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
1100         return ENOMEM;
1101     }
1102     iter->first = 1;
1103     *cursor = iter;
1104     return 0;
1105 }
1106
1107 static krb5_error_code KRB5_CALLCONV
1108 fcc_get_cache_next(krb5_context context, krb5_cc_cursor cursor, krb5_ccache *id)
1109 {
1110     struct fcache_iter *iter = cursor;
1111     krb5_error_code ret;
1112     const char *fn;
1113     char *expandedfn = NULL;
1114
1115     if (iter == NULL)
1116         return krb5_einval(context, 2);
1117
1118     if (!iter->first) {
1119         krb5_clear_error_message(context);
1120         return KRB5_CC_END;
1121     }
1122     iter->first = 0;
1123
1124     /*
1125      * Can't call krb5_cc_default_name here since it refers back to
1126      * krb5_cc_cache_match() which will call back into this function.
1127      *
1128      * Just use the default value if its set, otherwise, use the
1129      * default hardcoded value.
1130      */
1131     fn = context->default_cc_name;
1132     if (fn == NULL || strncasecmp(fn, "FILE:", 5) != 0) {
1133         ret = _krb5_expand_default_cc_name(context,
1134                                            KRB5_DEFAULT_CCNAME_FILE,
1135                                            &expandedfn);
1136         if (ret)
1137             return ret;
1138         fn = expandedfn;
1139     }
1140     /* check if file exists, don't return a non existant "next" */
1141     if (strncasecmp(fn, "FILE:", 5) == 0) {
1142         struct stat sb;
1143         ret = stat(fn + 5, &sb);
1144         if (ret) {
1145             ret = KRB5_CC_END;
1146             goto out;
1147         }
1148     }
1149     ret = krb5_cc_resolve(context, fn, id);
1150  out:
1151     if (expandedfn)
1152         free(expandedfn);
1153
1154     return ret;
1155 }
1156
1157 static krb5_error_code KRB5_CALLCONV
1158 fcc_end_cache_get(krb5_context context, krb5_cc_cursor cursor)
1159 {
1160     struct fcache_iter *iter = cursor;
1161
1162     if (iter == NULL)
1163         return krb5_einval(context, 2);
1164
1165     free(iter);
1166     return 0;
1167 }
1168
1169 static krb5_error_code KRB5_CALLCONV
1170 fcc_move(krb5_context context, krb5_ccache from, krb5_ccache to)
1171 {
1172     krb5_error_code ret = 0;
1173
1174     ret = rk_rename(FILENAME(from), FILENAME(to));
1175
1176     if (ret && errno != EXDEV) {
1177         char buf[128];
1178         ret = errno;
1179         rk_strerror_r(ret, buf, sizeof(buf));
1180         krb5_set_error_message(context, ret,
1181                                N_("Rename of file from %s "
1182                                   "to %s failed: %s", ""),
1183                                FILENAME(from), FILENAME(to), buf);
1184         return ret;
1185     } else if (ret && errno == EXDEV) {
1186         /* make a copy and delete the orignal */
1187         krb5_ssize_t sz1, sz2;
1188         int fd1, fd2;
1189         char buf[BUFSIZ];
1190
1191         ret = fcc_open(context, from, "move/from", &fd1, O_RDONLY | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0);
1192         if(ret)
1193             return ret;
1194
1195         unlink(FILENAME(to));
1196
1197         ret = fcc_open(context, to, "move/to", &fd2,
1198                        O_WRONLY | O_CREAT | O_EXCL | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0600);
1199         if(ret)
1200             goto out1;
1201
1202         while((sz1 = read(fd1, buf, sizeof(buf))) > 0) {
1203             sz2 = write(fd2, buf, sz1);
1204             if (sz1 != sz2) {
1205                 ret = EIO;
1206                 krb5_set_error_message(context, ret,
1207                                        N_("Failed to write data from one file "
1208                                           "credential cache to the other", ""));
1209                 goto out2;
1210             }
1211         }
1212         if (sz1 < 0) {
1213             ret = EIO;
1214             krb5_set_error_message(context, ret,
1215                                    N_("Failed to read data from one file "
1216                                       "credential cache to the other", ""));
1217             goto out2;
1218         }
1219     out2:
1220         fcc_unlock(context, fd2);
1221         close(fd2);
1222
1223     out1:
1224         fcc_unlock(context, fd1);
1225         close(fd1);
1226
1227         _krb5_erase_file(context, FILENAME(from));
1228
1229         if (ret) {
1230             _krb5_erase_file(context, FILENAME(to));
1231             return ret;
1232         }
1233     }
1234
1235     /* make sure ->version is uptodate */
1236     {
1237         krb5_storage *sp;
1238         int fd;
1239         if ((ret = init_fcc (context, to, "move", &sp, &fd, NULL)) == 0) {
1240             if (sp)
1241                 krb5_storage_free(sp);
1242             fcc_unlock(context, fd);
1243             close(fd);
1244         }
1245     }
1246
1247     fcc_close(context, from);
1248
1249     return ret;
1250 }
1251
1252 static krb5_error_code KRB5_CALLCONV
1253 fcc_get_default_name(krb5_context context, char **str)
1254 {
1255     return _krb5_expand_default_cc_name(context,
1256                                         KRB5_DEFAULT_CCNAME_FILE,
1257                                         str);
1258 }
1259
1260 static krb5_error_code KRB5_CALLCONV
1261 fcc_lastchange(krb5_context context, krb5_ccache id, krb5_timestamp *mtime)
1262 {
1263     krb5_error_code ret;
1264     struct stat sb;
1265     int fd;
1266
1267     ret = fcc_open(context, id, "lastchange", &fd, O_RDONLY | O_BINARY | O_CLOEXEC | O_NOFOLLOW, 0);
1268     if(ret)
1269         return ret;
1270     ret = fstat(fd, &sb);
1271     close(fd);
1272     if (ret) {
1273         ret = errno;
1274         krb5_set_error_message(context, ret, N_("Failed to stat cache file", ""));
1275         return ret;
1276     }
1277     *mtime = sb.st_mtime;
1278     return 0;
1279 }
1280
1281 static krb5_error_code KRB5_CALLCONV
1282 fcc_set_kdc_offset(krb5_context context, krb5_ccache id, krb5_deltat kdc_offset)
1283 {
1284     return 0;
1285 }
1286
1287 static krb5_error_code KRB5_CALLCONV
1288 fcc_get_kdc_offset(krb5_context context, krb5_ccache id, krb5_deltat *kdc_offset)
1289 {
1290     krb5_error_code ret;
1291     krb5_storage *sp = NULL;
1292     int fd;
1293     ret = init_fcc(context, id, "get-kdc-offset", &sp, &fd, kdc_offset);
1294     if (sp)
1295         krb5_storage_free(sp);
1296     fcc_unlock(context, fd);
1297     close(fd);
1298
1299     return ret;
1300 }
1301
1302
1303 /**
1304  * Variable containing the FILE based credential cache implemention.
1305  *
1306  * @ingroup krb5_ccache
1307  */
1308
1309 KRB5_LIB_VARIABLE const krb5_cc_ops krb5_fcc_ops = {
1310     KRB5_CC_OPS_VERSION,
1311     "FILE",
1312     fcc_get_name,
1313     fcc_resolve,
1314     fcc_gen_new,
1315     fcc_initialize,
1316     fcc_destroy,
1317     fcc_close,
1318     fcc_store_cred,
1319     NULL, /* fcc_retrieve */
1320     fcc_get_principal,
1321     fcc_get_first,
1322     fcc_get_next,
1323     fcc_end_get,
1324     fcc_remove_cred,
1325     fcc_set_flags,
1326     fcc_get_version,
1327     fcc_get_cache_first,
1328     fcc_get_cache_next,
1329     fcc_end_cache_get,
1330     fcc_move,
1331     fcc_get_default_name,
1332     NULL,
1333     fcc_lastchange,
1334     fcc_set_kdc_offset,
1335     fcc_get_kdc_offset
1336 };