summaryrefslogtreecommitdiff
path: root/source4/heimdal/lib/krb5/fcache.c
blob: f8ebe837b7137d14e9b5de07ee8e7a2a31e7406c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
/*
 * Copyright (c) 1997 - 2004 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden). 
 * All rights reserved. 
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 *
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 *
 * 3. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE. 
 */

#include "krb5_locl.h"

RCSID("$Id: fcache.c,v 1.51 2005/08/12 13:31:19 lha Exp $");

typedef struct krb5_fcache{
    char *filename;
    int version;
}krb5_fcache;

struct fcc_cursor {
    int fd;
    krb5_storage *sp;
};

#define KRB5_FCC_FVNO_1 1
#define KRB5_FCC_FVNO_2 2
#define KRB5_FCC_FVNO_3 3
#define KRB5_FCC_FVNO_4 4

#define FCC_TAG_DELTATIME 1

#define FCACHE(X) ((krb5_fcache*)(X)->data.data)

#define FILENAME(X) (FCACHE(X)->filename)

#define FCC_CURSOR(C) ((struct fcc_cursor*)(C))

static const char*
fcc_get_name(krb5_context context,
	     krb5_ccache id)
{
    return FILENAME(id);
}

int
_krb5_xlock(krb5_context context, int fd, krb5_boolean exclusive,
	    const char *filename)
{
    int ret;
#ifdef HAVE_FCNTL
    struct flock l;

    l.l_start = 0;
    l.l_len = 0;
    l.l_type = exclusive ? F_WRLCK : F_RDLCK;
    l.l_whence = SEEK_SET;
    ret = fcntl(fd, F_SETLKW, &l);
#else
    ret = flock(fd, exclusive ? LOCK_EX : LOCK_SH);
#endif
    if(ret < 0)
	ret = errno;
    if(ret == EACCES) /* fcntl can return EACCES instead of EAGAIN */
	ret = EAGAIN;

    switch (ret) {
    case 0:
	break;
    case EINVAL: /* filesystem doesn't support locking, let the user have it */
	ret = 0; 
	break;
    case EAGAIN:
	krb5_set_error_string(context, "timed out locking cache file %s", 
			      filename);
	break;
    default:
	krb5_set_error_string(context, "error locking cache file %s: %s",
			      filename, strerror(ret));
	break;
    }
    return ret;
}

int
_krb5_xunlock(krb5_context context, int fd)
{
    int ret;
#ifdef HAVE_FCNTL_LOCK
    struct flock l;
    l.l_start = 0;
    l.l_len = 0;
    l.l_type = F_UNLCK;
    l.l_whence = SEEK_SET;
    ret = fcntl(fd, F_SETLKW, &l);
#else
    ret = flock(fd, LOCK_UN);
#endif
    if (ret < 0)
	ret = errno;
    switch (ret) {
    case 0:
	break;
    case EINVAL: /* filesystem doesn't support locking, let the user have it */
	ret = 0; 
	break;
    default:
	krb5_set_error_string(context, 
			      "Failed to unlock file: %s", strerror(ret));
	break;
    }
    return ret;
}

static krb5_error_code
fcc_lock(krb5_context context, krb5_ccache id,
	 int fd, krb5_boolean exclusive)
{
    return _krb5_xlock(context, fd, exclusive, fcc_get_name(context, id));
}

static krb5_error_code
fcc_unlock(krb5_context context, int fd)
{
    return _krb5_xunlock(context, fd);
}

static krb5_error_code
fcc_resolve(krb5_context context, krb5_ccache *id, const char *res)
{
    krb5_fcache *f;
    f = malloc(sizeof(*f));
    if(f == NULL) {
	krb5_set_error_string(context, "malloc: out of memory");
	return KRB5_CC_NOMEM;
    }
    f->filename = strdup(res);
    if(f->filename == NULL){
	free(f);
	krb5_set_error_string(context, "malloc: out of memory");
	return KRB5_CC_NOMEM;
    }
    f->version = 0;
    (*id)->data.data = f;
    (*id)->data.length = sizeof(*f);
    return 0;
}

/*
 * Try to scrub the contents of `filename' safely.
 */

static int
scrub_file (int fd)
{
    off_t pos;
    char buf[128];

    pos = lseek(fd, 0, SEEK_END);
    if (pos < 0)
        return errno;
    if (lseek(fd, 0, SEEK_SET) < 0)
        return errno;
    memset(buf, 0, sizeof(buf));
    while(pos > 0) {
        ssize_t tmp = write(fd, buf, min(sizeof(buf), pos));

	if (tmp < 0)
	    return errno;
	pos -= tmp;
    }
    fsync (fd);
    return 0;
}

/*
 * Erase `filename' if it exists, trying to remove the contents if
 * it's `safe'.  We always try to remove the file, it it exists.  It's
 * only overwritten if it's a regular file (not a symlink and not a
 * hardlink)
 */

static krb5_error_code
erase_file(const char *filename)
{
    int fd;
    struct stat sb1, sb2;
    int ret;

    ret = lstat (filename, &sb1);
    if (ret < 0)
	return errno;

    fd = open(filename, O_RDWR | O_BINARY);
    if(fd < 0) {
	if(errno == ENOENT)
	    return 0;
	else
	    return errno;
    }
    if (unlink(filename) < 0) {
        close (fd);
        return errno;
    }
    ret = fstat (fd, &sb2);
    if (ret < 0) {
	close (fd);
	return errno;
    }

    /* check if someone was playing with symlinks */

    if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino) {
	close (fd);
	return EPERM;
    }

    /* there are still hard links to this file */

    if (sb2.st_nlink != 0) {
        close (fd);
        return 0;
    }

    ret = scrub_file (fd);
    close (fd);
    return ret;
}

static krb5_error_code
fcc_gen_new(krb5_context context, krb5_ccache *id)
{
    krb5_fcache *f;
    int fd;
    char *file;

    f = malloc(sizeof(*f));
    if(f == NULL) {
	krb5_set_error_string(context, "malloc: out of memory");
	return KRB5_CC_NOMEM;
    }
    asprintf (&file, "%sXXXXXX", KRB5_DEFAULT_CCFILE_ROOT);
    if(file == NULL) {
	free(f);
	krb5_set_error_string(context, "malloc: out of memory");
	return KRB5_CC_NOMEM;
    }
    fd = mkstemp(file);
    if(fd < 0) {
	free(f);
	free(file);
	krb5_set_error_string(context, "mkstemp %s", file);
	return errno;
    }
    close(fd);
    f->filename = file;
    f->version = 0;
    (*id)->data.data = f;
    (*id)->data.length = sizeof(*f);
    return 0;
}

static void
storage_set_flags(krb5_context context, krb5_storage *sp, int vno)
{
    int flags = 0;
    switch(vno) {
    case KRB5_FCC_FVNO_1:
	flags |= KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS;
	flags |= KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE;
	flags |= KRB5_STORAGE_HOST_BYTEORDER;
	break;
    case KRB5_FCC_FVNO_2:
	flags |= KRB5_STORAGE_HOST_BYTEORDER;
	break;
    case KRB5_FCC_FVNO_3:
	flags |= KRB5_STORAGE_KEYBLOCK_KEYTYPE_TWICE;
	break;
    case KRB5_FCC_FVNO_4:
	break;
    default:
	krb5_abortx(context, 
		    "storage_set_flags called with bad vno (%x)", vno);
    }
    krb5_storage_set_flags(sp, flags);
}

static krb5_error_code
fcc_open(krb5_context context,
	 krb5_ccache id,
	 int *fd_ret,
	 int flags,
	 mode_t mode)
{
    krb5_boolean exclusive = ((flags | O_WRONLY) == flags ||
			      (flags | O_RDWR) == flags);
    krb5_error_code ret;
    const char *filename = FILENAME(id);
    int fd;
    fd = open(filename, flags, mode);
    if(fd < 0) {
	ret = errno;
	krb5_set_error_string(context, "open(%s): %s", filename,
			      strerror(ret));
	return ret;
    }
	
    if((ret = fcc_lock(context, id, fd, exclusive)) != 0) {
	close(fd);
	return ret;
    }
    *fd_ret = fd;
    return 0;
}

static krb5_error_code
fcc_initialize(krb5_context context,
	       krb5_ccache id,
	       krb5_principal primary_principal)
{
    krb5_fcache *f = FCACHE(id);
    int ret = 0;
    int fd;
    char *filename = f->filename;

    unlink (filename);
  
    ret = fcc_open(context, id, &fd, O_RDWR | O_CREAT | O_EXCL | O_BINARY, 0600);
    if(ret)
	return ret;
    {
	krb5_storage *sp;    
	sp = krb5_storage_from_fd(fd);
	krb5_storage_set_eof_code(sp, KRB5_CC_END);
	if(context->fcache_vno != 0)
	    f->version = context->fcache_vno;
	else
	    f->version = KRB5_FCC_FVNO_4;
	ret |= krb5_store_int8(sp, 5);
	ret |= krb5_store_int8(sp, f->version);
	storage_set_flags(context, sp, f->version);
	if(f->version == KRB5_FCC_FVNO_4 && ret == 0) {
	    /* V4 stuff */
	    if (context->kdc_sec_offset) {
		ret |= krb5_store_int16 (sp, 12); /* length */
		ret |= krb5_store_int16 (sp, FCC_TAG_DELTATIME); /* Tag */
		ret |= krb5_store_int16 (sp, 8); /* length of data */
		ret |= krb5_store_int32 (sp, context->kdc_sec_offset);
		ret |= krb5_store_int32 (sp, context->kdc_usec_offset);
	    } else {
		ret |= krb5_store_int16 (sp, 0);
	    }
	}
	ret |= krb5_store_principal(sp, primary_principal);
	
	krb5_storage_free(sp);
    }
    fcc_unlock(context, fd);
    if (close(fd) < 0)
	if (ret == 0) {
	    ret = errno;
	    krb5_set_error_string (context, "close %s: %s", 
				   FILENAME(id), strerror(ret));
	}
    return ret;
}

static krb5_error_code
fcc_close(krb5_context context,
	  krb5_ccache id)
{
    free (FILENAME(id));
    krb5_data_free(&id->data);
    return 0;
}

static krb5_error_code
fcc_destroy(krb5_context context,
	    krb5_ccache id)
{
    erase_file(FILENAME(id));
    return 0;
}

static krb5_error_code
fcc_store_cred(krb5_context context,
	       krb5_ccache id,
	       krb5_creds *creds)
{
    int ret;
    int fd;

    ret = fcc_open(context, id, &fd, O_WRONLY | O_APPEND | O_BINARY, 0);
    if(ret)
	return ret;
    {
	krb5_storage *sp;
	sp = krb5_storage_from_fd(fd);
	krb5_storage_set_eof_code(sp, KRB5_CC_END);
	storage_set_flags(context, sp, FCACHE(id)->version);
	if (!krb5_config_get_bool_default(context, NULL, TRUE,
					  "libdefaults",
					  "fcc-mit-ticketflags",
					  NULL))
	    krb5_storage_set_flags(sp, KRB5_STORAGE_CREDS_FLAGS_WRONG_BITORDER);
	ret = krb5_store_creds(sp, creds);
	krb5_storage_free(sp);
    }
    fcc_unlock(context, fd);
    if (close(fd) < 0)
	if (ret == 0) {
	    ret = errno;
	    krb5_set_error_string (context, "close %s: %s", 
				   FILENAME(id), strerror(ret));
	}
    return ret;
}

static krb5_error_code
init_fcc (krb5_context context,
	  krb5_ccache id,
	  krb5_storage **ret_sp,
	  int *ret_fd)
{
    int fd;
    int8_t pvno, tag;
    krb5_storage *sp;
    krb5_error_code ret;

    ret = fcc_open(context, id, &fd, O_RDONLY | O_BINARY, 0);
    if(ret)
	return ret;
    
    sp = krb5_storage_from_fd(fd);
    if(sp == NULL) {
	krb5_clear_error_string(context);
	ret = ENOMEM;
	goto out;
    }
    krb5_storage_set_eof_code(sp, KRB5_CC_END);
    ret = krb5_ret_int8(sp, &pvno);
    if(ret != 0) {
	if(ret == KRB5_CC_END)
	    ret = ENOENT; /* empty file */
	krb5_clear_error_string(context);
	goto out;
    }
    if(pvno != 5) {
	krb5_set_error_string(context, "Bad version number in credential "
			      "cache file: %s", FILENAME(id));
	ret = KRB5_CCACHE_BADVNO;
	goto out;
    }
    ret = krb5_ret_int8(sp, &tag); /* should not be host byte order */
    if(ret != 0) {
	krb5_clear_error_string(context);
	ret = KRB5_CC_FORMAT;
	goto out;
    }
    FCACHE(id)->version = tag;
    storage_set_flags(context, sp, FCACHE(id)->version);
    switch (tag) {
    case KRB5_FCC_FVNO_4: {
	int16_t length;

	ret = krb5_ret_int16 (sp, &length);
	if(ret) {
	    ret = KRB5_CC_FORMAT;
	    krb5_clear_error_string(context);
	    goto out;
	}
	while(length > 0) {
	    int16_t dtag, data_len;
	    int i;
	    int8_t dummy;

	    ret = krb5_ret_int16 (sp, &dtag);
	    if(ret) {
		krb5_clear_error_string(context);
		ret = KRB5_CC_FORMAT;
		goto out;
	    }
	    ret = krb5_ret_int16 (sp, &data_len);
	    if(ret) {
		krb5_clear_error_string(context);
		ret = KRB5_CC_FORMAT;
		goto out;
	    }
	    switch (dtag) {
	    case FCC_TAG_DELTATIME :
		ret = krb5_ret_int32 (sp, &context->kdc_sec_offset);
		if(ret) {
		    krb5_clear_error_string(context);
		    ret = KRB5_CC_FORMAT;
		    goto out;
		}
		ret = krb5_ret_int32 (sp, &context->kdc_usec_offset);
		if(ret) {
		    krb5_clear_error_string(context);
		    ret = KRB5_CC_FORMAT;
		    goto out;
		}
		break;
	    default :
		for (i = 0; i < data_len; ++i) {
		    ret = krb5_ret_int8 (sp, &dummy);
		    if(ret) {
			krb5_clear_error_string(context);
			ret = KRB5_CC_FORMAT;
			goto out;
		    }
		}
		break;
	    }
	    length -= 4 + data_len;
	}
	break;
    }
    case KRB5_FCC_FVNO_3:
    case KRB5_FCC_FVNO_2:
    case KRB5_FCC_FVNO_1:
	break;
    default :
	ret = KRB5_CCACHE_BADVNO;
	krb5_set_error_string(context, "Unknown version number (%d) in "
			      "credential cache file: %s",
			      (int)tag, FILENAME(id));
	goto out;
    }
    *ret_sp = sp;
    *ret_fd = fd;
    
    return 0;
  out:
    if(sp != NULL)
	krb5_storage_free(sp);
    fcc_unlock(context, fd);
    close(fd);
    return ret;
}

static krb5_error_code
fcc_get_principal(krb5_context context,
		  krb5_ccache id,
		  krb5_principal *principal)
{
    krb5_error_code ret;
    int fd;
    krb5_storage *sp;

    ret = init_fcc (context, id, &sp, &fd);
    if (ret)
	return ret;
    ret = krb5_ret_principal(sp, principal);
    if (ret)
	krb5_clear_error_string(context);
    krb5_storage_free(sp);
    fcc_unlock(context, fd);
    close(fd);
    return ret;
}

static krb5_error_code
fcc_end_get (krb5_context context,
	     krb5_ccache id,
	     krb5_cc_cursor *cursor);

static krb5_error_code
fcc_get_first (krb5_context context,
	       krb5_ccache id,
	       krb5_cc_cursor *cursor)
{
    krb5_error_code ret;
    krb5_principal principal;

    *cursor = malloc(sizeof(struct fcc_cursor));
    if (*cursor == NULL) {
        krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    memset(*cursor, 0, sizeof(struct fcc_cursor));

    ret = init_fcc (context, id, &FCC_CURSOR(*cursor)->sp, 
		    &FCC_CURSOR(*cursor)->fd);
    if (ret) {
	free(*cursor);
	*cursor = NULL;
	return ret;
    }
    ret = krb5_ret_principal (FCC_CURSOR(*cursor)->sp, &principal);
    if(ret) {
	krb5_clear_error_string(context);
	fcc_end_get(context, id, cursor);
	return ret;
    }
    krb5_free_principal (context, principal);
    fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
    return 0;
}

static krb5_error_code
fcc_get_next (krb5_context context,
	      krb5_ccache id,
	      krb5_cc_cursor *cursor,
	      krb5_creds *creds)
{
    krb5_error_code ret;
    if((ret = fcc_lock(context, id, FCC_CURSOR(*cursor)->fd, FALSE)) != 0)
	return ret;

    ret = krb5_ret_creds(FCC_CURSOR(*cursor)->sp, creds);
    if (ret)
	krb5_clear_error_string(context);

    fcc_unlock(context, FCC_CURSOR(*cursor)->fd);
    return ret;
}

static krb5_error_code
fcc_end_get (krb5_context context,
	     krb5_ccache id,
	     krb5_cc_cursor *cursor)
{
    krb5_storage_free(FCC_CURSOR(*cursor)->sp);
    close (FCC_CURSOR(*cursor)->fd);
    free(*cursor);
    *cursor = NULL;
    return 0;
}

static krb5_error_code
fcc_remove_cred(krb5_context context,
		 krb5_ccache id,
		 krb5_flags which,
		 krb5_creds *cred)
{
    krb5_error_code ret;
    krb5_ccache copy;

    ret = krb5_cc_gen_new(context, &krb5_mcc_ops, &copy);
    if (ret)
	return ret;

    ret = krb5_cc_copy_cache(context, id, copy);
    if (ret) {
	krb5_cc_destroy(context, copy);
	return ret;
    }

    ret = krb5_cc_remove_cred(context, copy, which, cred);
    if (ret) {
	krb5_cc_destroy(context, copy);
	return ret;
    }

    fcc_destroy(context, id);

    ret = krb5_cc_copy_cache(context, copy, id);
    krb5_cc_destroy(context, copy);

    return ret;
}

static krb5_error_code
fcc_set_flags(krb5_context context,
	      krb5_ccache id,
	      krb5_flags flags)
{
    return 0; /* XXX */
}

static krb5_error_code
fcc_get_version(krb5_context context,
		krb5_ccache id)
{
    return FCACHE(id)->version;
}
		    
const krb5_cc_ops krb5_fcc_ops = {
    "FILE",
    fcc_get_name,
    fcc_resolve,
    fcc_gen_new,
    fcc_initialize,
    fcc_destroy,
    fcc_close,
    fcc_store_cred,
    NULL, /* fcc_retrieve */
    fcc_get_principal,
    fcc_get_first,
    fcc_get_next,
    fcc_end_get,
    fcc_remove_cred,
    fcc_set_flags,
    fcc_get_version
};