1/*	$NetBSD: fcache.c,v 1.2 2017/01/28 21:31:49 christos Exp $	*/
2
3/*
4 * Copyright (c) 1997 - 2008 Kungliga Tekniska H��gskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Portions Copyright (c) 2009 Apple Inc. All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 *
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 *
21 * 3. Neither the name of the Institute nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 */
37
38#include "krb5_locl.h"
39
40typedef struct krb5_fcache{
41    char *filename;
42    int version;
43}krb5_fcache;
44
45struct fcc_cursor {
46    int fd;
47    off_t cred_start;
48    off_t cred_end;
49    krb5_storage *sp;
50};
51
52#define KRB5_FCC_FVNO_1 1
53#define KRB5_FCC_FVNO_2 2
54#define KRB5_FCC_FVNO_3 3
55#define KRB5_FCC_FVNO_4 4
56
57#define FCC_TAG_DELTATIME 1
58
59#define FCACHE(X) ((krb5_fcache*)(X)->data.data)
60
61#define FILENAME(X) (FCACHE(X)->filename)
62
63#define FCC_CURSOR(C) ((struct fcc_cursor*)(C))
64
65static const char* KRB5_CALLCONV
66fcc_get_name(krb5_context context,
67	     krb5_ccache id)
68{
69    if (FCACHE(id) == NULL)
70        return NULL;
71
72    return FILENAME(id);
73}
74
75KRB5_LIB_FUNCTION int KRB5_LIB_CALL
76_krb5_xlock(krb5_context context, int fd, krb5_boolean exclusive,
77	    const char *filename)
78{
79    int ret;
80#ifdef HAVE_FCNTL
81    struct flock l;
82
83    l.l_start = 0;
84    l.l_len = 0;
85    l.l_type = exclusive ? F_WRLCK : F_RDLCK;
86    l.l_whence = SEEK_SET;
87    ret = fcntl(fd, F_SETLKW, &l);
88#else
89    ret = flock(fd, exclusive ? LOCK_EX : LOCK_SH);
90#endif
91    if(ret < 0)
92	ret = errno;
93    if(ret == EACCES) /* fcntl can return EACCES instead of EAGAIN */
94	ret = EAGAIN;
95
96    switch (ret) {
97    case 0:
98	break;
99    case EINVAL: /* filesystem doesn't support locking, let the user have it */
100	ret = 0;
101	break;
102    case EAGAIN:
103	krb5_set_error_message(context, ret,
104			       N_("timed out locking cache file %s", "file"),
105			       filename);
106	break;
107    default: {
108	char buf[128];
109	rk_strerror_r(ret, buf, sizeof(buf));
110	krb5_set_error_message(context, ret,
111			       N_("error locking cache file %s: %s",
112				  "file, error"), filename, buf);
113	break;
114    }
115    }
116    return ret;
117}
118
119KRB5_LIB_FUNCTION int KRB5_LIB_CALL
120_krb5_xunlock(krb5_context context, int fd)
121{
122    int ret;
123#ifdef HAVE_FCNTL
124    struct flock l;
125    l.l_start = 0;
126    l.l_len = 0;
127    l.l_type = F_UNLCK;
128    l.l_whence = SEEK_SET;
129    ret = fcntl(fd, F_SETLKW, &l);
130#else
131    ret = flock(fd, LOCK_UN);
132#endif
133    if (ret < 0)
134	ret = errno;
135    switch (ret) {
136    case 0:
137	break;
138    case EINVAL: /* filesystem doesn't support locking, let the user have it */
139	ret = 0;
140	break;
141    default: {
142	char buf[128];
143	rk_strerror_r(ret, buf, sizeof(buf));
144	krb5_set_error_message(context, ret,
145			       N_("Failed to unlock file: %s", ""), buf);
146	break;
147    }
148    }
149    return ret;
150}
151
152static krb5_error_code
153write_storage(krb5_context context, krb5_storage *sp, int fd)
154{
155    krb5_error_code ret;
156    krb5_data data;
157    ssize_t sret;
158
159    ret = krb5_storage_to_data(sp, &data);
160    if (ret) {
161	krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
162	return ret;
163    }
164    sret = write(fd, data.data, data.length);
165    ret = (sret != (ssize_t)data.length);
166    krb5_data_free(&data);
167    if (ret) {
168	ret = errno;
169	krb5_set_error_message(context, ret,
170			       N_("Failed to write FILE credential data", ""));
171	return ret;
172    }
173    return 0;
174}
175
176
177static krb5_error_code KRB5_CALLCONV
178fcc_lock(krb5_context context, krb5_ccache id,
179	 int fd, krb5_boolean exclusive)
180{
181    return _krb5_xlock(context, fd, exclusive, fcc_get_name(context, id));
182}
183
184static krb5_error_code KRB5_CALLCONV
185fcc_unlock(krb5_context context, int fd)
186{
187    return _krb5_xunlock(context, fd);
188}
189
190static krb5_error_code KRB5_CALLCONV
191fcc_resolve(krb5_context context, krb5_ccache *id, const char *res)
192{
193    krb5_fcache *f;
194    f = malloc(sizeof(*f));
195    if(f == NULL) {
196	krb5_set_error_message(context, KRB5_CC_NOMEM,
197			       N_("malloc: out of memory", ""));
198	return KRB5_CC_NOMEM;
199    }
200    f->filename = strdup(res);
201    if(f->filename == NULL){
202	free(f);
203	krb5_set_error_message(context, KRB5_CC_NOMEM,
204			       N_("malloc: out of memory", ""));
205	return KRB5_CC_NOMEM;
206    }
207    f->version = 0;
208    (*id)->data.data = f;
209    (*id)->data.length = sizeof(*f);
210    return 0;
211}
212
213/*
214 * Try to scrub the contents of `filename' safely.
215 */
216
217static int
218scrub_file (int fd)
219{
220    off_t pos;
221    char buf[128];
222
223    pos = lseek(fd, 0, SEEK_END);
224    if (pos < 0)
225        return errno;
226    if (lseek(fd, 0, SEEK_SET) < 0)
227        return errno;
228    memset(buf, 0, sizeof(buf));
229    while(pos > 0) {
230	ssize_t tmp;
231	size_t wr = sizeof(buf);
232	if (wr > pos)
233	    wr = (size_t)pos;
234        tmp = write(fd, buf, wr);
235
236	if (tmp < 0)
237	    return errno;
238	pos -= tmp;
239    }
240#ifdef _MSC_VER
241    _commit (fd);
242#else
243    fsync (fd);
244#endif
245    return 0;
246}
247
248/*
249 * Erase `filename' if it exists, trying to remove the contents if
250 * it's `safe'.  We always try to remove the file, it it exists.  It's
251 * only overwritten if it's a regular file (not a symlink and not a
252 * hardlink)
253 */
254
255KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
256_krb5_erase_file(krb5_context context, const char *filename)
257{
258    int fd;
259    struct stat sb1, sb2;
260    int ret;
261
262    ret = lstat (filename, &sb1);
263    if (ret < 0)
264	return errno;
265
266    fd = open(filename, O_RDWR | O_BINARY | O_CLOEXEC | O_NOFOLLOW);
267    if(fd < 0) {
268	if(errno == ENOENT)
269	    return 0;
270	else
271	    return errno;
272    }
273    rk_cloexec(fd);
274    ret = _krb5_xlock(context, fd, 1, filename);
275    if (ret) {
276	close(fd);
277	return ret;
278    }
279    if (unlink(filename) < 0) {
280	ret = errno;
281	_krb5_xunlock(context, fd);
282        close (fd);
283	krb5_set_error_message(context, errno,
284	    N_("krb5_cc_destroy: unlinking \"%s\": %s", ""),
285	    filename, strerror(ret));
286        return ret;
287    }
288    ret = fstat(fd, &sb2);
289    if (ret < 0) {
290	ret = errno;
291	_krb5_xunlock(context, fd);
292	close (fd);
293	return ret;
294    }
295
296    /* check if someone was playing with symlinks */
297
298    if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino) {
299	_krb5_xunlock(context, fd);
300	close(fd);
301	return EPERM;
302    }
303
304    /* there are still hard links to this file */
305
306    if (sb2.st_nlink != 0) {
307	_krb5_xunlock(context, fd);
308        close(fd);
309        return 0;
310    }
311
312    ret = scrub_file(fd);
313    if (ret) {
314	_krb5_xunlock(context, fd);
315	close(fd);
316	return ret;
317    }
318    ret = _krb5_xunlock(context, fd);
319    close(fd);
320    return ret;
321}
322
323static krb5_error_code KRB5_CALLCONV
324fcc_gen_new(krb5_context context, krb5_ccache *id)
325{
326    char *file = NULL, *exp_file = NULL;
327    krb5_error_code ret;
328    krb5_fcache *f;
329    int fd;
330
331    f = malloc(sizeof(*f));
332    if(f == NULL) {
333	krb5_set_error_message(context, KRB5_CC_NOMEM,
334			       N_("malloc: out of memory", ""));
335	return KRB5_CC_NOMEM;
336    }
337    ret = asprintf(&file, "%sXXXXXX", KRB5_DEFAULT_CCFILE_ROOT);
338    if(ret < 0 || file == NULL) {
339	free(f);
340	krb5_set_error_message(context, KRB5_CC_NOMEM,
341			       N_("malloc: out of memory", ""));
342	return KRB5_CC_NOMEM;
343    }
344    ret = _krb5_expand_path_tokens(context, file, 1, &exp_file);
345    free(file);
346    if (ret) {
347	free(f);
348	return ret;
349    }
350
351    file = exp_file;
352
353    fd = mkstemp(exp_file);
354    if(fd < 0) {
355	ret = (krb5_error_code)errno;
356	krb5_set_error_message(context, ret, N_("mkstemp %s failed", ""), exp_file);
357	free(f);
358	free(exp_file);
359	return ret;
360    }
361    close(fd);
362    f->filename = exp_file;
363    f->version = 0;
364    (*id)->data.data = f;
365    (*id)->data.length = sizeof(*f);
366    return 0;
367}
368
369static void
370storage_set_flags(krb5_context context, krb5_storage *sp, int vno)
371{
372    int flags = 0;
373    switch(vno) {
374    case KRB5_FCC_FVNO_1:
375	flags |= KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS;
376	flags |= KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE;
377	flags |= KRB5_STORAGE_HOST_BYTEORDER;
378	break;
379    case KRB5_FCC_FVNO_2:
380	flags |= KRB5_STORAGE_HOST_BYTEORDER;
381	break;
382    case KRB5_FCC_FVNO_3:
383	flags |= KRB5_STORAGE_KEYBLOCK_KEYTYPE_TWICE;
384	break;
385    case KRB5_FCC_FVNO_4:
386	break;
387    default:
388	krb5_abortx(context,
389		    "storage_set_flags called with bad vno (%x)", vno);
390    }
391    krb5_storage_set_flags(sp, flags);
392}
393
394static krb5_error_code KRB5_CALLCONV
395fcc_open(krb5_context context,
396	 krb5_ccache id,
397	 const char *operation,
398	 int *fd_ret,
399	 int flags,
400	 mode_t mode)
401{
402    krb5_boolean exclusive = ((flags | O_WRONLY) == flags ||
403			      (flags | O_RDWR) == flags);
404    krb5_error_code ret;
405    const char *filename;
406    struct stat sb1, sb2;
407#ifndef _WIN32
408    struct stat sb3;
409    size_t tries = 3;
410#endif
411    int strict_checking;
412    int fd;
413
414    flags |= O_BINARY | O_CLOEXEC | O_NOFOLLOW;
415
416    *fd_ret = -1;
417
418    if (FCACHE(id) == NULL)
419        return krb5_einval(context, 2);
420
421    filename = FILENAME(id);
422
423    strict_checking = (flags & O_CREAT) == 0 &&
424	(context->flags & KRB5_CTX_F_FCACHE_STRICT_CHECKING) != 0;
425
426again:
427    memset(&sb1, 0, sizeof(sb1));
428    ret = lstat(filename, &sb1);
429    if (ret == 0) {
430	if (!S_ISREG(sb1.st_mode)) {
431	    krb5_set_error_message(context, EPERM,
432				   N_("Refuses to open symlinks for caches FILE:%s", ""), filename);
433	    return EPERM;
434	}
435    } else if (errno != ENOENT || !(flags & O_CREAT)) {
436	krb5_set_error_message(context, errno, N_("%s lstat(%s)", "file, error"),
437			       operation, filename);
438	return errno;
439    }
440
441    fd = open(filename, flags, mode);
442    if(fd < 0) {
443	char buf[128];
444	ret = errno;
445	rk_strerror_r(ret, buf, sizeof(buf));
446	krb5_set_error_message(context, ret, N_("%s open(%s): %s", "file, error"),
447			       operation, filename, buf);
448	return ret;
449    }
450    rk_cloexec(fd);
451
452    ret = fstat(fd, &sb2);
453    if (ret < 0) {
454	krb5_clear_error_message(context);
455	close(fd);
456	return errno;
457    }
458
459    if (!S_ISREG(sb2.st_mode)) {
460	krb5_set_error_message(context, EPERM, N_("Refuses to open non files caches: FILE:%s", ""), filename);
461	close(fd);
462	return EPERM;
463    }
464
465#ifndef _WIN32
466    if (sb1.st_dev && sb1.st_ino &&
467	(sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino)) {
468	/*
469	 * Perhaps we raced with a rename().  To complain about
470	 * symlinks in that case would cause unnecessary concern, so
471	 * we check for that possibility and loop.  This has no
472	 * TOCTOU problems because we redo the open().  We could also
473	 * not do any of this checking if O_NOFOLLOW != 0...
474	 */
475	close(fd);
476	ret = lstat(filename, &sb3);
477	if (ret || sb1.st_dev != sb2.st_dev ||
478	    sb3.st_dev != sb2.st_dev || sb3.st_ino != sb2.st_ino) {
479	    krb5_set_error_message(context, EPERM, N_("Refuses to open possible symlink for caches: FILE:%s", ""), filename);
480	    return EPERM;
481	}
482	if (--tries == 0) {
483	    krb5_set_error_message(context, EPERM, N_("Raced too many times with renames of FILE:%s", ""), filename);
484	    return EPERM;
485	}
486	goto again;
487    }
488#endif
489
490    /*
491     * /tmp (or wherever default ccaches go) might not be on its own
492     * filesystem, or on a filesystem different /etc, say, and even if
493     * it were, suppose a user hard-links another's ccache to her
494     * default ccache, then runs a set-uid program that will user her
495     * default ccache (even if it ignores KRB5CCNAME)...
496     *
497     * Default ccache locations should really be on per-user non-tmp
498     * locations on tmpfs "run" directories.  But we don't know here
499     * that this is the case.  Thus: no hard-links, no symlinks.
500     */
501    if (sb2.st_nlink != 1) {
502	krb5_set_error_message(context, EPERM, N_("Refuses to open hardlinks for caches FILE:%s", ""), filename);
503	close(fd);
504	return EPERM;
505    }
506
507    if (strict_checking) {
508#ifndef _WIN32
509	/*
510	 * XXX WIN32: Needs to have ACL checking code!
511	 * st_mode comes out as 100666, and st_uid is no use.
512	 */
513	/*
514	 * XXX Should probably add options to improve control over this
515	 * check.  We might want strict checking of everything except
516	 * this.
517	 */
518	if (sb2.st_uid != geteuid()) {
519	    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);
520	    close(fd);
521	    return EPERM;
522	}
523	if ((sb2.st_mode & 077) != 0) {
524	    krb5_set_error_message(context, EPERM,
525				   N_("Refuses to open group/other readable files FILE:%s", ""), filename);
526	    close(fd);
527	    return EPERM;
528	}
529#endif
530    }
531
532    if((ret = fcc_lock(context, id, fd, exclusive)) != 0) {
533	close(fd);
534	return ret;
535    }
536    *fd_ret = fd;
537    return 0;
538}
539
540static krb5_error_code KRB5_CALLCONV
541fcc_initialize(krb5_context context,
542	       krb5_ccache id,
543	       krb5_principal primary_principal)
544{
545    krb5_fcache *f = FCACHE(id);
546    int ret = 0;
547    int fd;
548
549    if (f == NULL)
550        return krb5_einval(context, 2);
551
552    unlink (f->filename);
553
554    ret = fcc_open(context, id, "initialize", &fd, O_RDWR | O_CREAT | O_EXCL, 0600);
555    if(ret)
556	return ret;
557    {
558	krb5_storage *sp;
559	sp = krb5_storage_emem();
560	krb5_storage_set_eof_code(sp, KRB5_CC_END);
561	if(context->fcache_vno != 0)
562	    f->version = context->fcache_vno;
563	else
564	    f->version = KRB5_FCC_FVNO_4;
565	ret |= krb5_store_int8(sp, 5);
566	ret |= krb5_store_int8(sp, f->version);
567	storage_set_flags(context, sp, f->version);
568	if(f->version == KRB5_FCC_FVNO_4 && ret == 0) {
569	    /* V4 stuff */
570	    if (context->kdc_sec_offset) {
571		ret |= krb5_store_int16 (sp, 12); /* length */
572		ret |= krb5_store_int16 (sp, FCC_TAG_DELTATIME); /* Tag */
573		ret |= krb5_store_int16 (sp, 8); /* length of data */
574		ret |= krb5_store_int32 (sp, context->kdc_sec_offset);
575		ret |= krb5_store_int32 (sp, context->kdc_usec_offset);
576	    } else {
577		ret |= krb5_store_int16 (sp, 0);
578	    }
579	}
580	ret |= krb5_store_principal(sp, primary_principal);
581
582	ret |= write_storage(context, sp, fd);
583
584	krb5_storage_free(sp);
585    }
586    fcc_unlock(context, fd);
587    if (close(fd) < 0)
588	if (ret == 0) {
589	    char buf[128];
590	    ret = errno;
591	    rk_strerror_r(ret, buf, sizeof(buf));
592	    krb5_set_error_message(context, ret, N_("close %s: %s", ""),
593				   FILENAME(id), buf);
594	}
595    return ret;
596}
597
598static krb5_error_code KRB5_CALLCONV
599fcc_close(krb5_context context,
600	  krb5_ccache id)
601{
602    if (FCACHE(id) == NULL)
603        return krb5_einval(context, 2);
604
605    free (FILENAME(id));
606    krb5_data_free(&id->data);
607    return 0;
608}
609
610static krb5_error_code KRB5_CALLCONV
611fcc_destroy(krb5_context context,
612	    krb5_ccache id)
613{
614    if (FCACHE(id) == NULL)
615        return krb5_einval(context, 2);
616
617    return _krb5_erase_file(context, FILENAME(id));
618}
619
620static krb5_error_code KRB5_CALLCONV
621fcc_store_cred(krb5_context context,
622	       krb5_ccache id,
623	       krb5_creds *creds)
624{
625    int ret;
626    int fd;
627
628    ret = fcc_open(context, id, "store", &fd, O_WRONLY | O_APPEND, 0);
629    if(ret)
630	return ret;
631    {
632	krb5_storage *sp;
633
634	sp = krb5_storage_emem();
635	krb5_storage_set_eof_code(sp, KRB5_CC_END);
636	storage_set_flags(context, sp, FCACHE(id)->version);
637	ret = krb5_store_creds(sp, creds);
638	if (ret == 0)
639	    ret = write_storage(context, sp, fd);
640	krb5_storage_free(sp);
641    }
642    fcc_unlock(context, fd);
643    if (close(fd) < 0) {
644	if (ret == 0) {
645	    char buf[128];
646	    ret = errno;
647	    rk_strerror_r(ret, buf, sizeof(buf));
648	    krb5_set_error_message(context, ret, N_("close %s: %s", ""),
649				   FILENAME(id), buf);
650	}
651    }
652    return ret;
653}
654
655static krb5_error_code
656init_fcc(krb5_context context,
657	 krb5_ccache id,
658	 const char *operation,
659	 krb5_storage **ret_sp,
660	 int *ret_fd,
661	 krb5_deltat *kdc_offset)
662{
663    int fd;
664    int8_t pvno, tag;
665    krb5_storage *sp;
666    krb5_error_code ret;
667
668    *ret_fd = -1;
669    *ret_sp = NULL;
670    if (kdc_offset)
671	*kdc_offset = 0;
672
673    ret = fcc_open(context, id, operation, &fd, O_RDONLY, 0);
674    if(ret)
675	return ret;
676
677    sp = krb5_storage_from_fd(fd);
678    if(sp == NULL) {
679	krb5_clear_error_message(context);
680	ret = ENOMEM;
681	goto out;
682    }
683    krb5_storage_set_eof_code(sp, KRB5_CC_END);
684    ret = krb5_ret_int8(sp, &pvno);
685    if (ret != 0) {
686	if(ret == KRB5_CC_END) {
687	    ret = ENOENT;
688	    krb5_set_error_message(context, ret,
689				   N_("Empty credential cache file: %s", ""),
690				   FILENAME(id));
691	} else
692	    krb5_set_error_message(context, ret, N_("Error reading pvno "
693						    "in cache file: %s", ""),
694				   FILENAME(id));
695	goto out;
696    }
697    if (pvno != 5) {
698	ret = KRB5_CCACHE_BADVNO;
699	krb5_set_error_message(context, ret, N_("Bad version number in credential "
700						"cache file: %s", ""),
701			       FILENAME(id));
702	goto out;
703    }
704    ret = krb5_ret_int8(sp, &tag); /* should not be host byte order */
705    if (ret != 0) {
706	ret = KRB5_CC_FORMAT;
707	krb5_set_error_message(context, ret, "Error reading tag in "
708			      "cache file: %s", FILENAME(id));
709	goto out;
710    }
711    FCACHE(id)->version = tag;
712    storage_set_flags(context, sp, FCACHE(id)->version);
713    switch (tag) {
714    case KRB5_FCC_FVNO_4: {
715	int16_t length;
716
717	ret = krb5_ret_int16 (sp, &length);
718	if(ret) {
719	    ret = KRB5_CC_FORMAT;
720	    krb5_set_error_message(context, ret,
721				   N_("Error reading tag length in "
722				      "cache file: %s", ""), FILENAME(id));
723	    goto out;
724	}
725	while(length > 0) {
726	    int16_t dtag, data_len;
727	    int i;
728	    int8_t dummy;
729
730	    ret = krb5_ret_int16 (sp, &dtag);
731	    if(ret) {
732		ret = KRB5_CC_FORMAT;
733		krb5_set_error_message(context, ret, N_("Error reading dtag in "
734							"cache file: %s", ""),
735				       FILENAME(id));
736		goto out;
737	    }
738	    ret = krb5_ret_int16 (sp, &data_len);
739	    if(ret) {
740		ret = KRB5_CC_FORMAT;
741		krb5_set_error_message(context, ret,
742				       N_("Error reading dlength "
743					  "in cache file: %s",""),
744				       FILENAME(id));
745		goto out;
746	    }
747	    switch (dtag) {
748	    case FCC_TAG_DELTATIME : {
749		int32_t offset;
750
751		ret = krb5_ret_int32 (sp, &offset);
752		ret |= krb5_ret_int32 (sp, &context->kdc_usec_offset);
753		if(ret) {
754		    ret = KRB5_CC_FORMAT;
755		    krb5_set_error_message(context, ret,
756					   N_("Error reading kdc_sec in "
757					      "cache file: %s", ""),
758					   FILENAME(id));
759		    goto out;
760		}
761		context->kdc_sec_offset = offset;
762		if (kdc_offset)
763		    *kdc_offset = offset;
764		break;
765	    }
766	    default :
767		for (i = 0; i < data_len; ++i) {
768		    ret = krb5_ret_int8 (sp, &dummy);
769		    if(ret) {
770			ret = KRB5_CC_FORMAT;
771			krb5_set_error_message(context, ret,
772					       N_("Error reading unknown "
773						  "tag in cache file: %s", ""),
774					       FILENAME(id));
775			goto out;
776		    }
777		}
778		break;
779	    }
780	    length -= 4 + data_len;
781	}
782	break;
783    }
784    case KRB5_FCC_FVNO_3:
785    case KRB5_FCC_FVNO_2:
786    case KRB5_FCC_FVNO_1:
787	break;
788    default :
789	ret = KRB5_CCACHE_BADVNO;
790	krb5_set_error_message(context, ret,
791			       N_("Unknown version number (%d) in "
792				  "credential cache file: %s", ""),
793			       (int)tag, FILENAME(id));
794	goto out;
795    }
796    *ret_sp = sp;
797    *ret_fd = fd;
798
799    return 0;
800  out:
801    if(sp != NULL)
802	krb5_storage_free(sp);
803    fcc_unlock(context, fd);
804    close(fd);
805    return ret;
806}
807
808static krb5_error_code KRB5_CALLCONV
809fcc_get_principal(krb5_context context,
810		  krb5_ccache id,
811		  krb5_principal *principal)
812{
813    krb5_error_code ret;
814    int fd;
815    krb5_storage *sp;
816
817    ret = init_fcc (context, id, "get-principal", &sp, &fd, NULL);
818    if (ret)
819	return ret;
820    ret = krb5_ret_principal(sp, principal);
821    if (ret)
822	krb5_clear_error_message(context);
823    krb5_storage_free(sp);
824    fcc_unlock(context, fd);
825    close(fd);
826    return ret;
827}
828
829static krb5_error_code KRB5_CALLCONV
830fcc_end_get (krb5_context context,
831	     krb5_ccache id,
832	     krb5_cc_cursor *cursor);
833
834static krb5_error_code KRB5_CALLCONV
835fcc_get_first (krb5_context context,
836	       krb5_ccache id,
837	       krb5_cc_cursor *cursor)
838{
839    krb5_error_code ret;
840    krb5_principal principal;
841
842    if (FCACHE(id) == NULL)
843        return krb5_einval(context, 2);
844
845    *cursor = malloc(sizeof(struct fcc_cursor));
846    if (*cursor == NULL) {
847        krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
848	return ENOMEM;
849    }
850    memset(*cursor, 0, sizeof(struct fcc_cursor));
851
852    ret = init_fcc(context, id, "get-frist", &FCC_CURSOR(*cursor)->sp,
853		   &FCC_CURSOR(*cursor)->fd, NULL);
854    if (ret) {
855	free(*cursor);
856	*cursor = NULL;
857	return ret;
858    }
859    ret = krb5_ret_principal (FCC_CURSOR(*cursor)->sp, &principal);
860    if(ret) {
861	krb5_clear_error_message(context);
862	fcc_end_get(context, id, cursor);
863	return ret;
864    }
865    krb5_free_principal (context, principal);
866    fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
867    return 0;
868}
869
870static krb5_error_code KRB5_CALLCONV
871fcc_get_next (krb5_context context,
872	      krb5_ccache id,
873	      krb5_cc_cursor *cursor,
874	      krb5_creds *creds)
875{
876    krb5_error_code ret;
877
878    if (FCACHE(id) == NULL)
879        return krb5_einval(context, 2);
880
881    if (FCC_CURSOR(*cursor) == NULL)
882        return krb5_einval(context, 3);
883
884    if((ret = fcc_lock(context, id, FCC_CURSOR(*cursor)->fd, FALSE)) != 0)
885	return ret;
886    FCC_CURSOR(*cursor)->cred_start = lseek(FCC_CURSOR(*cursor)->fd,
887					   0, SEEK_CUR);
888
889    ret = krb5_ret_creds(FCC_CURSOR(*cursor)->sp, creds);
890    if (ret)
891	krb5_clear_error_message(context);
892
893    FCC_CURSOR(*cursor)->cred_end = lseek(FCC_CURSOR(*cursor)->fd,
894					 0, SEEK_CUR);
895
896    fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
897    return ret;
898}
899
900static krb5_error_code KRB5_CALLCONV
901fcc_end_get (krb5_context context,
902	     krb5_ccache id,
903	     krb5_cc_cursor *cursor)
904{
905
906    if (FCACHE(id) == NULL)
907        return krb5_einval(context, 2);
908
909    if (FCC_CURSOR(*cursor) == NULL)
910        return krb5_einval(context, 3);
911
912    krb5_storage_free(FCC_CURSOR(*cursor)->sp);
913    close (FCC_CURSOR(*cursor)->fd);
914    free(*cursor);
915    *cursor = NULL;
916    return 0;
917}
918
919static void KRB5_CALLCONV
920cred_delete(krb5_context context,
921	    krb5_ccache id,
922	    krb5_cc_cursor *cursor,
923	    krb5_creds *cred)
924{
925    krb5_error_code ret;
926    krb5_storage *sp;
927    krb5_data orig_cred_data;
928    unsigned char *cred_data_in_file = NULL;
929    off_t new_cred_sz;
930    struct stat sb1, sb2;
931    int fd = -1;
932    ssize_t bytes;
933    krb5_const_realm srealm = krb5_principal_get_realm(context, cred->server);
934
935    /* This is best-effort code; if we lose track of errors here it's OK */
936
937    heim_assert(FCC_CURSOR(*cursor)->cred_start < FCC_CURSOR(*cursor)->cred_end,
938		"fcache internal error");
939
940    krb5_data_zero(&orig_cred_data);
941
942    sp = krb5_storage_emem();
943    if (sp == NULL)
944	return;
945    krb5_storage_set_eof_code(sp, KRB5_CC_END);
946    storage_set_flags(context, sp, FCACHE(id)->version);
947
948    /* Get a copy of what the cred should look like in the file; see below */
949    ret = krb5_store_creds(sp, cred);
950    if (ret)
951	goto out;
952
953    ret = krb5_storage_to_data(sp, &orig_cred_data);
954    if (ret)
955	goto out;
956    krb5_storage_free(sp);
957
958    cred_data_in_file = malloc(orig_cred_data.length);
959    if (cred_data_in_file == NULL)
960	goto out;
961
962    /*
963     * Mark the cred expired; krb5_cc_retrieve_cred() callers should use
964     * KRB5_TC_MATCH_TIMES, so this should be good enough...
965     */
966    cred->times.endtime = 0;
967
968    /* ...except for config creds because we don't check their endtimes */
969    if (srealm && strcmp(srealm, "X-CACHECONF:") == 0) {
970	ret = krb5_principal_set_realm(context, cred->server, "X-RMED-CONF:");
971	if (ret)
972	    goto out;
973    }
974
975    sp = krb5_storage_emem();
976    if (sp == NULL)
977	goto out;
978    krb5_storage_set_eof_code(sp, KRB5_CC_END);
979    storage_set_flags(context, sp, FCACHE(id)->version);
980
981    ret = krb5_store_creds(sp, cred);
982
983    /* The new cred must be the same size as the old cred */
984    new_cred_sz = krb5_storage_seek(sp, 0, SEEK_END);
985    if (new_cred_sz != orig_cred_data.length || new_cred_sz !=
986	(FCC_CURSOR(*cursor)->cred_end - FCC_CURSOR(*cursor)->cred_start)) {
987	/* XXX This really can't happen.  Assert like above? */
988	krb5_set_error_message(context, EINVAL,
989			       N_("Credential deletion failed on ccache "
990				  "FILE:%s: new credential size did not "
991				  "match old credential size", ""),
992			       FILENAME(id));
993	goto out;
994    }
995
996    ret = fcc_open(context, id, "remove_cred", &fd, O_RDWR, 0);
997    if (ret)
998	goto out;
999
1000    /*
1001     * Check that we're updating the same file where we got the
1002     * cred's offset, else we'd be corrupting a new ccache.
1003     */
1004    if (fstat(FCC_CURSOR(*cursor)->fd, &sb1) == -1 ||
1005	fstat(fd, &sb2) == -1)
1006	goto out;
1007    if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino)
1008	goto out;
1009
1010    /*
1011     * Make sure what we overwrite is what we expected.
1012     *
1013     * FIXME: We *really* need the ccache v4 tag for ccache ID.  This
1014     * check that we're only overwriting something that looks exactly
1015     * like what we want to is probably good enough in practice, but
1016     * it's not guaranteed to work.
1017     */
1018    if (lseek(fd, FCC_CURSOR(*cursor)->cred_start, SEEK_SET) == (off_t)-1)
1019	goto out;
1020    bytes = read(fd, cred_data_in_file, orig_cred_data.length);
1021    if (bytes != orig_cred_data.length)
1022	goto out;
1023    if (memcmp(orig_cred_data.data, cred_data_in_file, bytes) != 0)
1024	goto out;
1025    if (lseek(fd, FCC_CURSOR(*cursor)->cred_start, SEEK_SET) == (off_t)-1)
1026	goto out;
1027    ret = write_storage(context, sp, fd);
1028out:
1029    if (fd > -1) {
1030	fcc_unlock(context, fd);
1031	if (close(fd) < 0 && ret == 0) {
1032	    krb5_set_error_message(context, errno, N_("close %s", ""),
1033				   FILENAME(id));
1034	}
1035    }
1036    krb5_data_free(&orig_cred_data);
1037    free(cred_data_in_file);
1038    krb5_storage_free(sp);
1039    return;
1040}
1041
1042static krb5_error_code KRB5_CALLCONV
1043fcc_remove_cred(krb5_context context,
1044		krb5_ccache id,
1045		krb5_flags which,
1046		krb5_creds *mcred)
1047{
1048    krb5_error_code ret, ret2;
1049    krb5_cc_cursor cursor;
1050    krb5_creds found_cred;
1051
1052    if (FCACHE(id) == NULL)
1053	return krb5_einval(context, 2);
1054
1055    ret = krb5_cc_start_seq_get(context, id, &cursor);
1056    if (ret)
1057	return ret;
1058    while ((ret = krb5_cc_next_cred(context, id, &cursor, &found_cred)) == 0) {
1059	if (!krb5_compare_creds(context, which, mcred, &found_cred)) {
1060            krb5_free_cred_contents(context, &found_cred);
1061	    continue;
1062        }
1063	cred_delete(context, id, &cursor, &found_cred);
1064	krb5_free_cred_contents(context, &found_cred);
1065    }
1066    ret2 = krb5_cc_end_seq_get(context, id, &cursor);
1067    if (ret == 0)
1068	return ret2;
1069    if (ret == KRB5_CC_END)
1070	return 0;
1071    return ret;
1072}
1073
1074static krb5_error_code KRB5_CALLCONV
1075fcc_set_flags(krb5_context context,
1076	      krb5_ccache id,
1077	      krb5_flags flags)
1078{
1079    if (FCACHE(id) == NULL)
1080        return krb5_einval(context, 2);
1081
1082    return 0; /* XXX */
1083}
1084
1085static int KRB5_CALLCONV
1086fcc_get_version(krb5_context context,
1087		krb5_ccache id)
1088{
1089    if (FCACHE(id) == NULL)
1090        return -1;
1091
1092    return FCACHE(id)->version;
1093}
1094
1095struct fcache_iter {
1096    int first;
1097};
1098
1099static krb5_error_code KRB5_CALLCONV
1100fcc_get_cache_first(krb5_context context, krb5_cc_cursor *cursor)
1101{
1102    struct fcache_iter *iter;
1103
1104    iter = calloc(1, sizeof(*iter));
1105    if (iter == NULL) {
1106	krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
1107	return ENOMEM;
1108    }
1109    iter->first = 1;
1110    *cursor = iter;
1111    return 0;
1112}
1113
1114static krb5_error_code KRB5_CALLCONV
1115fcc_get_cache_next(krb5_context context, krb5_cc_cursor cursor, krb5_ccache *id)
1116{
1117    struct fcache_iter *iter = cursor;
1118    krb5_error_code ret;
1119    const char *fn, *cc_type;
1120    krb5_ccache cc;
1121
1122    if (iter == NULL)
1123        return krb5_einval(context, 2);
1124
1125    if (!iter->first) {
1126	krb5_clear_error_message(context);
1127	return KRB5_CC_END;
1128    }
1129    iter->first = 0;
1130
1131    /*
1132     * Note: do not allow krb5_cc_default_name() to recurse via
1133     * krb5_cc_cache_match().
1134     * Note that context->default_cc_name will be NULL even though
1135     * KRB5CCNAME is set in the environment if
1136     * krb5_cc_set_default_name() hasn't
1137     */
1138    fn = krb5_cc_default_name(context);
1139    ret = krb5_cc_resolve(context, fn, &cc);
1140    if (ret != 0)
1141        return ret;
1142    cc_type = krb5_cc_get_type(context, cc);
1143    if (strcmp(cc_type, "FILE") != 0) {
1144        krb5_cc_close(context, cc);
1145        return KRB5_CC_END;
1146    }
1147
1148    *id = cc;
1149
1150    return 0;
1151}
1152
1153static krb5_error_code KRB5_CALLCONV
1154fcc_end_cache_get(krb5_context context, krb5_cc_cursor cursor)
1155{
1156    struct fcache_iter *iter = cursor;
1157
1158    if (iter == NULL)
1159        return krb5_einval(context, 2);
1160
1161    free(iter);
1162    return 0;
1163}
1164
1165static krb5_error_code KRB5_CALLCONV
1166fcc_move(krb5_context context, krb5_ccache from, krb5_ccache to)
1167{
1168    krb5_error_code ret = 0;
1169
1170    ret = rk_rename(FILENAME(from), FILENAME(to));
1171
1172    if (ret && errno != EXDEV) {
1173	char buf[128];
1174	ret = errno;
1175	rk_strerror_r(ret, buf, sizeof(buf));
1176	krb5_set_error_message(context, ret,
1177			       N_("Rename of file from %s "
1178				  "to %s failed: %s", ""),
1179			       FILENAME(from), FILENAME(to), buf);
1180	return ret;
1181    } else if (ret && errno == EXDEV) {
1182	/* make a copy and delete the orignal */
1183	krb5_ssize_t sz1, sz2;
1184	int fd1, fd2;
1185	char buf[BUFSIZ];
1186
1187	ret = fcc_open(context, from, "move/from", &fd1, O_RDONLY, 0);
1188	if(ret)
1189	    return ret;
1190
1191	unlink(FILENAME(to));
1192
1193	ret = fcc_open(context, to, "move/to", &fd2,
1194		       O_WRONLY | O_CREAT | O_EXCL, 0600);
1195	if(ret)
1196	    goto out1;
1197
1198	while((sz1 = read(fd1, buf, sizeof(buf))) > 0) {
1199	    sz2 = write(fd2, buf, sz1);
1200	    if (sz1 != sz2) {
1201		ret = EIO;
1202		krb5_set_error_message(context, ret,
1203				       N_("Failed to write data from one file "
1204					  "credential cache to the other", ""));
1205		goto out2;
1206	    }
1207	}
1208	if (sz1 < 0) {
1209	    ret = EIO;
1210	    krb5_set_error_message(context, ret,
1211				   N_("Failed to read data from one file "
1212				      "credential cache to the other", ""));
1213	    goto out2;
1214	}
1215    out2:
1216	fcc_unlock(context, fd2);
1217	close(fd2);
1218
1219    out1:
1220	fcc_unlock(context, fd1);
1221	close(fd1);
1222
1223	_krb5_erase_file(context, FILENAME(from));
1224
1225	if (ret) {
1226	    _krb5_erase_file(context, FILENAME(to));
1227	    return ret;
1228	}
1229    }
1230
1231    /* make sure ->version is uptodate */
1232    {
1233	krb5_storage *sp;
1234	int fd;
1235	if ((ret = init_fcc (context, to, "move", &sp, &fd, NULL)) == 0) {
1236	    if (sp)
1237		krb5_storage_free(sp);
1238	    fcc_unlock(context, fd);
1239	    close(fd);
1240	}
1241    }
1242
1243    fcc_close(context, from);
1244
1245    return ret;
1246}
1247
1248static krb5_error_code KRB5_CALLCONV
1249fcc_get_default_name(krb5_context context, char **str)
1250{
1251    return _krb5_expand_default_cc_name(context,
1252					KRB5_DEFAULT_CCNAME_FILE,
1253					str);
1254}
1255
1256static krb5_error_code KRB5_CALLCONV
1257fcc_lastchange(krb5_context context, krb5_ccache id, krb5_timestamp *mtime)
1258{
1259    krb5_error_code ret;
1260    struct stat sb;
1261    int fd;
1262
1263    ret = fcc_open(context, id, "lastchange", &fd, O_RDONLY, 0);
1264    if(ret)
1265	return ret;
1266    ret = fstat(fd, &sb);
1267    close(fd);
1268    if (ret) {
1269	ret = errno;
1270	krb5_set_error_message(context, ret, N_("Failed to stat cache file", ""));
1271	return ret;
1272    }
1273    *mtime = sb.st_mtime;
1274    return 0;
1275}
1276
1277static krb5_error_code KRB5_CALLCONV
1278fcc_set_kdc_offset(krb5_context context, krb5_ccache id, krb5_deltat kdc_offset)
1279{
1280    return 0;
1281}
1282
1283static krb5_error_code KRB5_CALLCONV
1284fcc_get_kdc_offset(krb5_context context, krb5_ccache id, krb5_deltat *kdc_offset)
1285{
1286    krb5_error_code ret;
1287    krb5_storage *sp = NULL;
1288    int fd;
1289    ret = init_fcc(context, id, "get-kdc-offset", &sp, &fd, kdc_offset);
1290    if (sp)
1291	krb5_storage_free(sp);
1292    fcc_unlock(context, fd);
1293    close(fd);
1294
1295    return ret;
1296}
1297
1298
1299/**
1300 * Variable containing the FILE based credential cache implemention.
1301 *
1302 * @ingroup krb5_ccache
1303 */
1304
1305KRB5_LIB_VARIABLE const krb5_cc_ops krb5_fcc_ops = {
1306    KRB5_CC_OPS_VERSION,
1307    "FILE",
1308    fcc_get_name,
1309    fcc_resolve,
1310    fcc_gen_new,
1311    fcc_initialize,
1312    fcc_destroy,
1313    fcc_close,
1314    fcc_store_cred,
1315    NULL, /* fcc_retrieve */
1316    fcc_get_principal,
1317    fcc_get_first,
1318    fcc_get_next,
1319    fcc_end_get,
1320    fcc_remove_cred,
1321    fcc_set_flags,
1322    fcc_get_version,
1323    fcc_get_cache_first,
1324    fcc_get_cache_next,
1325    fcc_end_cache_get,
1326    fcc_move,
1327    fcc_get_default_name,
1328    NULL,
1329    fcc_lastchange,
1330    fcc_set_kdc_offset,
1331    fcc_get_kdc_offset
1332};
1333