forked from analogdevicesinc/linux
-
Notifications
You must be signed in to change notification settings - Fork 3
/
cifsacl.c
1118 lines (958 loc) · 30.4 KB
/
cifsacl.c
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
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* fs/cifs/cifsacl.c
*
* Copyright (C) International Business Machines Corp., 2007,2008
* Author(s): Steve French ([email protected])
*
* Contains the routines for mapping CIFS/NTFS ACLs
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/keyctl.h>
#include <linux/key-type.h>
#include <keys/user-type.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsacl.h"
#include "cifsproto.h"
#include "cifs_debug.h"
/* security id for everyone/world system group */
static const struct cifs_sid sid_everyone = {
1, 1, {0, 0, 0, 0, 0, 1}, {0} };
/* security id for Authenticated Users system group */
static const struct cifs_sid sid_authusers = {
1, 1, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(11)} };
/* group users */
static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} };
static const struct cred *root_cred;
static int
cifs_idmap_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
{
char *payload;
/*
* If the payload is less than or equal to the size of a pointer, then
* an allocation here is wasteful. Just copy the data directly to the
* payload.value union member instead.
*
* With this however, you must check the datalen before trying to
* dereference payload.data!
*/
if (prep->datalen <= sizeof(key->payload)) {
key->payload.data[0] = NULL;
memcpy(&key->payload, prep->data, prep->datalen);
} else {
payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
if (!payload)
return -ENOMEM;
key->payload.data[0] = payload;
}
key->datalen = prep->datalen;
return 0;
}
static inline void
cifs_idmap_key_destroy(struct key *key)
{
if (key->datalen > sizeof(key->payload))
kfree(key->payload.data[0]);
}
static struct key_type cifs_idmap_key_type = {
.name = "cifs.idmap",
.instantiate = cifs_idmap_key_instantiate,
.destroy = cifs_idmap_key_destroy,
.describe = user_describe,
};
static char *
sid_to_key_str(struct cifs_sid *sidptr, unsigned int type)
{
int i, len;
unsigned int saval;
char *sidstr, *strptr;
unsigned long long id_auth_val;
/* 3 bytes for prefix */
sidstr = kmalloc(3 + SID_STRING_BASE_SIZE +
(SID_STRING_SUBAUTH_SIZE * sidptr->num_subauth),
GFP_KERNEL);
if (!sidstr)
return sidstr;
strptr = sidstr;
len = sprintf(strptr, "%cs:S-%hhu", type == SIDOWNER ? 'o' : 'g',
sidptr->revision);
strptr += len;
/* The authority field is a single 48-bit number */
id_auth_val = (unsigned long long)sidptr->authority[5];
id_auth_val |= (unsigned long long)sidptr->authority[4] << 8;
id_auth_val |= (unsigned long long)sidptr->authority[3] << 16;
id_auth_val |= (unsigned long long)sidptr->authority[2] << 24;
id_auth_val |= (unsigned long long)sidptr->authority[1] << 32;
id_auth_val |= (unsigned long long)sidptr->authority[0] << 48;
/*
* MS-DTYP states that if the authority is >= 2^32, then it should be
* expressed as a hex value.
*/
if (id_auth_val <= UINT_MAX)
len = sprintf(strptr, "-%llu", id_auth_val);
else
len = sprintf(strptr, "-0x%llx", id_auth_val);
strptr += len;
for (i = 0; i < sidptr->num_subauth; ++i) {
saval = le32_to_cpu(sidptr->sub_auth[i]);
len = sprintf(strptr, "-%u", saval);
strptr += len;
}
return sidstr;
}
/*
* if the two SIDs (roughly equivalent to a UUID for a user or group) are
* the same returns zero, if they do not match returns non-zero.
*/
static int
compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid)
{
int i;
int num_subauth, num_sat, num_saw;
if ((!ctsid) || (!cwsid))
return 1;
/* compare the revision */
if (ctsid->revision != cwsid->revision) {
if (ctsid->revision > cwsid->revision)
return 1;
else
return -1;
}
/* compare all of the six auth values */
for (i = 0; i < NUM_AUTHS; ++i) {
if (ctsid->authority[i] != cwsid->authority[i]) {
if (ctsid->authority[i] > cwsid->authority[i])
return 1;
else
return -1;
}
}
/* compare all of the subauth values if any */
num_sat = ctsid->num_subauth;
num_saw = cwsid->num_subauth;
num_subauth = num_sat < num_saw ? num_sat : num_saw;
if (num_subauth) {
for (i = 0; i < num_subauth; ++i) {
if (ctsid->sub_auth[i] != cwsid->sub_auth[i]) {
if (le32_to_cpu(ctsid->sub_auth[i]) >
le32_to_cpu(cwsid->sub_auth[i]))
return 1;
else
return -1;
}
}
}
return 0; /* sids compare/match */
}
static void
cifs_copy_sid(struct cifs_sid *dst, const struct cifs_sid *src)
{
int i;
dst->revision = src->revision;
dst->num_subauth = min_t(u8, src->num_subauth, SID_MAX_SUB_AUTHORITIES);
for (i = 0; i < NUM_AUTHS; ++i)
dst->authority[i] = src->authority[i];
for (i = 0; i < dst->num_subauth; ++i)
dst->sub_auth[i] = src->sub_auth[i];
}
static int
id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid)
{
int rc;
struct key *sidkey;
struct cifs_sid *ksid;
unsigned int ksid_size;
char desc[3 + 10 + 1]; /* 3 byte prefix + 10 bytes for value + NULL */
const struct cred *saved_cred;
rc = snprintf(desc, sizeof(desc), "%ci:%u",
sidtype == SIDOWNER ? 'o' : 'g', cid);
if (rc >= sizeof(desc))
return -EINVAL;
rc = 0;
saved_cred = override_creds(root_cred);
sidkey = request_key(&cifs_idmap_key_type, desc, "");
if (IS_ERR(sidkey)) {
rc = -EINVAL;
cifs_dbg(FYI, "%s: Can't map %cid %u to a SID\n",
__func__, sidtype == SIDOWNER ? 'u' : 'g', cid);
goto out_revert_creds;
} else if (sidkey->datalen < CIFS_SID_BASE_SIZE) {
rc = -EIO;
cifs_dbg(FYI, "%s: Downcall contained malformed key (datalen=%hu)\n",
__func__, sidkey->datalen);
goto invalidate_key;
}
/*
* A sid is usually too large to be embedded in payload.value, but if
* there are no subauthorities and the host has 8-byte pointers, then
* it could be.
*/
ksid = sidkey->datalen <= sizeof(sidkey->payload) ?
(struct cifs_sid *)&sidkey->payload :
(struct cifs_sid *)sidkey->payload.data[0];
ksid_size = CIFS_SID_BASE_SIZE + (ksid->num_subauth * sizeof(__le32));
if (ksid_size > sidkey->datalen) {
rc = -EIO;
cifs_dbg(FYI, "%s: Downcall contained malformed key (datalen=%hu, ksid_size=%u)\n",
__func__, sidkey->datalen, ksid_size);
goto invalidate_key;
}
cifs_copy_sid(ssid, ksid);
out_key_put:
key_put(sidkey);
out_revert_creds:
revert_creds(saved_cred);
return rc;
invalidate_key:
key_invalidate(sidkey);
goto out_key_put;
}
static int
sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
struct cifs_fattr *fattr, uint sidtype)
{
int rc;
struct key *sidkey;
char *sidstr;
const struct cred *saved_cred;
kuid_t fuid = cifs_sb->mnt_uid;
kgid_t fgid = cifs_sb->mnt_gid;
/*
* If we have too many subauthorities, then something is really wrong.
* Just return an error.
*/
if (unlikely(psid->num_subauth > SID_MAX_SUB_AUTHORITIES)) {
cifs_dbg(FYI, "%s: %u subauthorities is too many!\n",
__func__, psid->num_subauth);
return -EIO;
}
sidstr = sid_to_key_str(psid, sidtype);
if (!sidstr)
return -ENOMEM;
saved_cred = override_creds(root_cred);
sidkey = request_key(&cifs_idmap_key_type, sidstr, "");
if (IS_ERR(sidkey)) {
rc = -EINVAL;
cifs_dbg(FYI, "%s: Can't map SID %s to a %cid\n",
__func__, sidstr, sidtype == SIDOWNER ? 'u' : 'g');
goto out_revert_creds;
}
/*
* FIXME: Here we assume that uid_t and gid_t are same size. It's
* probably a safe assumption but might be better to check based on
* sidtype.
*/
BUILD_BUG_ON(sizeof(uid_t) != sizeof(gid_t));
if (sidkey->datalen != sizeof(uid_t)) {
rc = -EIO;
cifs_dbg(FYI, "%s: Downcall contained malformed key (datalen=%hu)\n",
__func__, sidkey->datalen);
key_invalidate(sidkey);
goto out_key_put;
}
if (sidtype == SIDOWNER) {
kuid_t uid;
uid_t id;
memcpy(&id, &sidkey->payload.data[0], sizeof(uid_t));
uid = make_kuid(&init_user_ns, id);
if (uid_valid(uid))
fuid = uid;
} else {
kgid_t gid;
gid_t id;
memcpy(&id, &sidkey->payload.data[0], sizeof(gid_t));
gid = make_kgid(&init_user_ns, id);
if (gid_valid(gid))
fgid = gid;
}
out_key_put:
key_put(sidkey);
out_revert_creds:
revert_creds(saved_cred);
kfree(sidstr);
/*
* Note that we return 0 here unconditionally. If the mapping
* fails then we just fall back to using the mnt_uid/mnt_gid.
*/
if (sidtype == SIDOWNER)
fattr->cf_uid = fuid;
else
fattr->cf_gid = fgid;
return 0;
}
int
init_cifs_idmap(void)
{
struct cred *cred;
struct key *keyring;
int ret;
cifs_dbg(FYI, "Registering the %s key type\n",
cifs_idmap_key_type.name);
/* create an override credential set with a special thread keyring in
* which requests are cached
*
* this is used to prevent malicious redirections from being installed
* with add_key().
*/
cred = prepare_kernel_cred(NULL);
if (!cred)
return -ENOMEM;
keyring = keyring_alloc(".cifs_idmap",
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
(KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ,
KEY_ALLOC_NOT_IN_QUOTA, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto failed_put_cred;
}
ret = register_key_type(&cifs_idmap_key_type);
if (ret < 0)
goto failed_put_key;
/* instruct request_key() to use this special keyring as a cache for
* the results it looks up */
set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
cred->thread_keyring = keyring;
cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
root_cred = cred;
cifs_dbg(FYI, "cifs idmap keyring: %d\n", key_serial(keyring));
return 0;
failed_put_key:
key_put(keyring);
failed_put_cred:
put_cred(cred);
return ret;
}
void
exit_cifs_idmap(void)
{
key_revoke(root_cred->thread_keyring);
unregister_key_type(&cifs_idmap_key_type);
put_cred(root_cred);
cifs_dbg(FYI, "Unregistered %s key type\n", cifs_idmap_key_type.name);
}
/* copy ntsd, owner sid, and group sid from a security descriptor to another */
static void copy_sec_desc(const struct cifs_ntsd *pntsd,
struct cifs_ntsd *pnntsd, __u32 sidsoffset)
{
struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
struct cifs_sid *nowner_sid_ptr, *ngroup_sid_ptr;
/* copy security descriptor control portion */
pnntsd->revision = pntsd->revision;
pnntsd->type = pntsd->type;
pnntsd->dacloffset = cpu_to_le32(sizeof(struct cifs_ntsd));
pnntsd->sacloffset = 0;
pnntsd->osidoffset = cpu_to_le32(sidsoffset);
pnntsd->gsidoffset = cpu_to_le32(sidsoffset + sizeof(struct cifs_sid));
/* copy owner sid */
owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
le32_to_cpu(pntsd->osidoffset));
nowner_sid_ptr = (struct cifs_sid *)((char *)pnntsd + sidsoffset);
cifs_copy_sid(nowner_sid_ptr, owner_sid_ptr);
/* copy group sid */
group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
le32_to_cpu(pntsd->gsidoffset));
ngroup_sid_ptr = (struct cifs_sid *)((char *)pnntsd + sidsoffset +
sizeof(struct cifs_sid));
cifs_copy_sid(ngroup_sid_ptr, group_sid_ptr);
return;
}
/*
change posix mode to reflect permissions
pmode is the existing mode (we only want to overwrite part of this
bits to set can be: S_IRWXU, S_IRWXG or S_IRWXO ie 00700 or 00070 or 00007
*/
static void access_flags_to_mode(__le32 ace_flags, int type, umode_t *pmode,
umode_t *pbits_to_set)
{
__u32 flags = le32_to_cpu(ace_flags);
/* the order of ACEs is important. The canonical order is to begin with
DENY entries followed by ALLOW, otherwise an allow entry could be
encountered first, making the subsequent deny entry like "dead code"
which would be superflous since Windows stops when a match is made
for the operation you are trying to perform for your user */
/* For deny ACEs we change the mask so that subsequent allow access
control entries do not turn on the bits we are denying */
if (type == ACCESS_DENIED) {
if (flags & GENERIC_ALL)
*pbits_to_set &= ~S_IRWXUGO;
if ((flags & GENERIC_WRITE) ||
((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
*pbits_to_set &= ~S_IWUGO;
if ((flags & GENERIC_READ) ||
((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
*pbits_to_set &= ~S_IRUGO;
if ((flags & GENERIC_EXECUTE) ||
((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
*pbits_to_set &= ~S_IXUGO;
return;
} else if (type != ACCESS_ALLOWED) {
cifs_dbg(VFS, "unknown access control type %d\n", type);
return;
}
/* else ACCESS_ALLOWED type */
if (flags & GENERIC_ALL) {
*pmode |= (S_IRWXUGO & (*pbits_to_set));
cifs_dbg(NOISY, "all perms\n");
return;
}
if ((flags & GENERIC_WRITE) ||
((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
*pmode |= (S_IWUGO & (*pbits_to_set));
if ((flags & GENERIC_READ) ||
((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
*pmode |= (S_IRUGO & (*pbits_to_set));
if ((flags & GENERIC_EXECUTE) ||
((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
*pmode |= (S_IXUGO & (*pbits_to_set));
cifs_dbg(NOISY, "access flags 0x%x mode now 0x%x\n", flags, *pmode);
return;
}
/*
Generate access flags to reflect permissions mode is the existing mode.
This function is called for every ACE in the DACL whose SID matches
with either owner or group or everyone.
*/
static void mode_to_access_flags(umode_t mode, umode_t bits_to_use,
__u32 *pace_flags)
{
/* reset access mask */
*pace_flags = 0x0;
/* bits to use are either S_IRWXU or S_IRWXG or S_IRWXO */
mode &= bits_to_use;
/* check for R/W/X UGO since we do not know whose flags
is this but we have cleared all the bits sans RWX for
either user or group or other as per bits_to_use */
if (mode & S_IRUGO)
*pace_flags |= SET_FILE_READ_RIGHTS;
if (mode & S_IWUGO)
*pace_flags |= SET_FILE_WRITE_RIGHTS;
if (mode & S_IXUGO)
*pace_flags |= SET_FILE_EXEC_RIGHTS;
cifs_dbg(NOISY, "mode: 0x%x, access flags now 0x%x\n",
mode, *pace_flags);
return;
}
static __u16 fill_ace_for_sid(struct cifs_ace *pntace,
const struct cifs_sid *psid, __u64 nmode, umode_t bits)
{
int i;
__u16 size = 0;
__u32 access_req = 0;
pntace->type = ACCESS_ALLOWED;
pntace->flags = 0x0;
mode_to_access_flags(nmode, bits, &access_req);
if (!access_req)
access_req = SET_MINIMUM_RIGHTS;
pntace->access_req = cpu_to_le32(access_req);
pntace->sid.revision = psid->revision;
pntace->sid.num_subauth = psid->num_subauth;
for (i = 0; i < NUM_AUTHS; i++)
pntace->sid.authority[i] = psid->authority[i];
for (i = 0; i < psid->num_subauth; i++)
pntace->sid.sub_auth[i] = psid->sub_auth[i];
size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth * 4);
pntace->size = cpu_to_le16(size);
return size;
}
#ifdef CONFIG_CIFS_DEBUG2
static void dump_ace(struct cifs_ace *pace, char *end_of_acl)
{
int num_subauth;
/* validate that we do not go past end of acl */
if (le16_to_cpu(pace->size) < 16) {
cifs_dbg(VFS, "ACE too small %d\n", le16_to_cpu(pace->size));
return;
}
if (end_of_acl < (char *)pace + le16_to_cpu(pace->size)) {
cifs_dbg(VFS, "ACL too small to parse ACE\n");
return;
}
num_subauth = pace->sid.num_subauth;
if (num_subauth) {
int i;
cifs_dbg(FYI, "ACE revision %d num_auth %d type %d flags %d size %d\n",
pace->sid.revision, pace->sid.num_subauth, pace->type,
pace->flags, le16_to_cpu(pace->size));
for (i = 0; i < num_subauth; ++i) {
cifs_dbg(FYI, "ACE sub_auth[%d]: 0x%x\n",
i, le32_to_cpu(pace->sid.sub_auth[i]));
}
/* BB add length check to make sure that we do not have huge
num auths and therefore go off the end */
}
return;
}
#endif
static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
struct cifs_fattr *fattr)
{
int i;
int num_aces = 0;
int acl_size;
char *acl_base;
struct cifs_ace **ppace;
/* BB need to add parm so we can store the SID BB */
if (!pdacl) {
/* no DACL in the security descriptor, set
all the permissions for user/group/other */
fattr->cf_mode |= S_IRWXUGO;
return;
}
/* validate that we do not go past end of acl */
if (end_of_acl < (char *)pdacl + le16_to_cpu(pdacl->size)) {
cifs_dbg(VFS, "ACL too small to parse DACL\n");
return;
}
cifs_dbg(NOISY, "DACL revision %d size %d num aces %d\n",
le16_to_cpu(pdacl->revision), le16_to_cpu(pdacl->size),
le32_to_cpu(pdacl->num_aces));
/* reset rwx permissions for user/group/other.
Also, if num_aces is 0 i.e. DACL has no ACEs,
user/group/other have no permissions */
fattr->cf_mode &= ~(S_IRWXUGO);
acl_base = (char *)pdacl;
acl_size = sizeof(struct cifs_acl);
num_aces = le32_to_cpu(pdacl->num_aces);
if (num_aces > 0) {
umode_t user_mask = S_IRWXU;
umode_t group_mask = S_IRWXG;
umode_t other_mask = S_IRWXU | S_IRWXG | S_IRWXO;
if (num_aces > ULONG_MAX / sizeof(struct cifs_ace *))
return;
ppace = kmalloc(num_aces * sizeof(struct cifs_ace *),
GFP_KERNEL);
if (!ppace)
return;
for (i = 0; i < num_aces; ++i) {
ppace[i] = (struct cifs_ace *) (acl_base + acl_size);
#ifdef CONFIG_CIFS_DEBUG2
dump_ace(ppace[i], end_of_acl);
#endif
if (compare_sids(&(ppace[i]->sid), pownersid) == 0)
access_flags_to_mode(ppace[i]->access_req,
ppace[i]->type,
&fattr->cf_mode,
&user_mask);
if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0)
access_flags_to_mode(ppace[i]->access_req,
ppace[i]->type,
&fattr->cf_mode,
&group_mask);
if (compare_sids(&(ppace[i]->sid), &sid_everyone) == 0)
access_flags_to_mode(ppace[i]->access_req,
ppace[i]->type,
&fattr->cf_mode,
&other_mask);
if (compare_sids(&(ppace[i]->sid), &sid_authusers) == 0)
access_flags_to_mode(ppace[i]->access_req,
ppace[i]->type,
&fattr->cf_mode,
&other_mask);
/* memcpy((void *)(&(cifscred->aces[i])),
(void *)ppace[i],
sizeof(struct cifs_ace)); */
acl_base = (char *)ppace[i];
acl_size = le16_to_cpu(ppace[i]->size);
}
kfree(ppace);
}
return;
}
static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid,
struct cifs_sid *pgrpsid, __u64 nmode)
{
u16 size = 0;
struct cifs_acl *pnndacl;
pnndacl = (struct cifs_acl *)((char *)pndacl + sizeof(struct cifs_acl));
size += fill_ace_for_sid((struct cifs_ace *) ((char *)pnndacl + size),
pownersid, nmode, S_IRWXU);
size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
pgrpsid, nmode, S_IRWXG);
size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
&sid_everyone, nmode, S_IRWXO);
pndacl->size = cpu_to_le16(size + sizeof(struct cifs_acl));
pndacl->num_aces = cpu_to_le32(3);
return 0;
}
static int parse_sid(struct cifs_sid *psid, char *end_of_acl)
{
/* BB need to add parm so we can store the SID BB */
/* validate that we do not go past end of ACL - sid must be at least 8
bytes long (assuming no sub-auths - e.g. the null SID */
if (end_of_acl < (char *)psid + 8) {
cifs_dbg(VFS, "ACL too small to parse SID %p\n", psid);
return -EINVAL;
}
#ifdef CONFIG_CIFS_DEBUG2
if (psid->num_subauth) {
int i;
cifs_dbg(FYI, "SID revision %d num_auth %d\n",
psid->revision, psid->num_subauth);
for (i = 0; i < psid->num_subauth; i++) {
cifs_dbg(FYI, "SID sub_auth[%d]: 0x%x\n",
i, le32_to_cpu(psid->sub_auth[i]));
}
/* BB add length check to make sure that we do not have huge
num auths and therefore go off the end */
cifs_dbg(FYI, "RID 0x%x\n",
le32_to_cpu(psid->sub_auth[psid->num_subauth-1]));
}
#endif
return 0;
}
/* Convert CIFS ACL to POSIX form */
static int parse_sec_desc(struct cifs_sb_info *cifs_sb,
struct cifs_ntsd *pntsd, int acl_len, struct cifs_fattr *fattr)
{
int rc = 0;
struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
struct cifs_acl *dacl_ptr; /* no need for SACL ptr */
char *end_of_acl = ((char *)pntsd) + acl_len;
__u32 dacloffset;
if (pntsd == NULL)
return -EIO;
owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
le32_to_cpu(pntsd->osidoffset));
group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
le32_to_cpu(pntsd->gsidoffset));
dacloffset = le32_to_cpu(pntsd->dacloffset);
dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
cifs_dbg(NOISY, "revision %d type 0x%x ooffset 0x%x goffset 0x%x sacloffset 0x%x dacloffset 0x%x\n",
pntsd->revision, pntsd->type, le32_to_cpu(pntsd->osidoffset),
le32_to_cpu(pntsd->gsidoffset),
le32_to_cpu(pntsd->sacloffset), dacloffset);
/* cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */
rc = parse_sid(owner_sid_ptr, end_of_acl);
if (rc) {
cifs_dbg(FYI, "%s: Error %d parsing Owner SID\n", __func__, rc);
return rc;
}
rc = sid_to_id(cifs_sb, owner_sid_ptr, fattr, SIDOWNER);
if (rc) {
cifs_dbg(FYI, "%s: Error %d mapping Owner SID to uid\n",
__func__, rc);
return rc;
}
rc = parse_sid(group_sid_ptr, end_of_acl);
if (rc) {
cifs_dbg(FYI, "%s: Error %d mapping Owner SID to gid\n",
__func__, rc);
return rc;
}
rc = sid_to_id(cifs_sb, group_sid_ptr, fattr, SIDGROUP);
if (rc) {
cifs_dbg(FYI, "%s: Error %d mapping Group SID to gid\n",
__func__, rc);
return rc;
}
if (dacloffset)
parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr,
group_sid_ptr, fattr);
else
cifs_dbg(FYI, "no ACL\n"); /* BB grant all or default perms? */
return rc;
}
/* Convert permission bits from mode to equivalent CIFS ACL */
static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
__u32 secdesclen, __u64 nmode, kuid_t uid, kgid_t gid, int *aclflag)
{
int rc = 0;
__u32 dacloffset;
__u32 ndacloffset;
__u32 sidsoffset;
struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
struct cifs_sid *nowner_sid_ptr, *ngroup_sid_ptr;
struct cifs_acl *dacl_ptr = NULL; /* no need for SACL ptr */
struct cifs_acl *ndacl_ptr = NULL; /* no need for SACL ptr */
if (nmode != NO_CHANGE_64) { /* chmod */
owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
le32_to_cpu(pntsd->osidoffset));
group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
le32_to_cpu(pntsd->gsidoffset));
dacloffset = le32_to_cpu(pntsd->dacloffset);
dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
ndacloffset = sizeof(struct cifs_ntsd);
ndacl_ptr = (struct cifs_acl *)((char *)pnntsd + ndacloffset);
ndacl_ptr->revision = dacl_ptr->revision;
ndacl_ptr->size = 0;
ndacl_ptr->num_aces = 0;
rc = set_chmod_dacl(ndacl_ptr, owner_sid_ptr, group_sid_ptr,
nmode);
sidsoffset = ndacloffset + le16_to_cpu(ndacl_ptr->size);
/* copy sec desc control portion & owner and group sids */
copy_sec_desc(pntsd, pnntsd, sidsoffset);
*aclflag = CIFS_ACL_DACL;
} else {
memcpy(pnntsd, pntsd, secdesclen);
if (uid_valid(uid)) { /* chown */
uid_t id;
owner_sid_ptr = (struct cifs_sid *)((char *)pnntsd +
le32_to_cpu(pnntsd->osidoffset));
nowner_sid_ptr = kmalloc(sizeof(struct cifs_sid),
GFP_KERNEL);
if (!nowner_sid_ptr)
return -ENOMEM;
id = from_kuid(&init_user_ns, uid);
rc = id_to_sid(id, SIDOWNER, nowner_sid_ptr);
if (rc) {
cifs_dbg(FYI, "%s: Mapping error %d for owner id %d\n",
__func__, rc, id);
kfree(nowner_sid_ptr);
return rc;
}
cifs_copy_sid(owner_sid_ptr, nowner_sid_ptr);
kfree(nowner_sid_ptr);
*aclflag = CIFS_ACL_OWNER;
}
if (gid_valid(gid)) { /* chgrp */
gid_t id;
group_sid_ptr = (struct cifs_sid *)((char *)pnntsd +
le32_to_cpu(pnntsd->gsidoffset));
ngroup_sid_ptr = kmalloc(sizeof(struct cifs_sid),
GFP_KERNEL);
if (!ngroup_sid_ptr)
return -ENOMEM;
id = from_kgid(&init_user_ns, gid);
rc = id_to_sid(id, SIDGROUP, ngroup_sid_ptr);
if (rc) {
cifs_dbg(FYI, "%s: Mapping error %d for group id %d\n",
__func__, rc, id);
kfree(ngroup_sid_ptr);
return rc;
}
cifs_copy_sid(group_sid_ptr, ngroup_sid_ptr);
kfree(ngroup_sid_ptr);
*aclflag = CIFS_ACL_GROUP;
}
}
return rc;
}
struct cifs_ntsd *get_cifs_acl_by_fid(struct cifs_sb_info *cifs_sb,
const struct cifs_fid *cifsfid, u32 *pacllen)
{
struct cifs_ntsd *pntsd = NULL;
unsigned int xid;
int rc;
struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return ERR_CAST(tlink);
xid = get_xid();
rc = CIFSSMBGetCIFSACL(xid, tlink_tcon(tlink), cifsfid->netfid, &pntsd,
pacllen);
free_xid(xid);
cifs_put_tlink(tlink);
cifs_dbg(FYI, "%s: rc = %d ACL len %d\n", __func__, rc, *pacllen);
if (rc)
return ERR_PTR(rc);
return pntsd;
}
static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
const char *path, u32 *pacllen)
{
struct cifs_ntsd *pntsd = NULL;
int oplock = 0;
unsigned int xid;
int rc, create_options = 0;
struct cifs_tcon *tcon;
struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
struct cifs_fid fid;
struct cifs_open_parms oparms;
if (IS_ERR(tlink))
return ERR_CAST(tlink);
tcon = tlink_tcon(tlink);
xid = get_xid();
if (backup_cred(cifs_sb))
create_options |= CREATE_OPEN_BACKUP_INTENT;
oparms.tcon = tcon;
oparms.cifs_sb = cifs_sb;
oparms.desired_access = READ_CONTROL;
oparms.create_options = create_options;
oparms.disposition = FILE_OPEN;
oparms.path = path;
oparms.fid = &fid;
oparms.reconnect = false;
rc = CIFS_open(xid, &oparms, &oplock, NULL);
if (!rc) {
rc = CIFSSMBGetCIFSACL(xid, tcon, fid.netfid, &pntsd, pacllen);
CIFSSMBClose(xid, tcon, fid.netfid);
}
cifs_put_tlink(tlink);
free_xid(xid);
cifs_dbg(FYI, "%s: rc = %d ACL len %d\n", __func__, rc, *pacllen);
if (rc)
return ERR_PTR(rc);
return pntsd;
}
/* Retrieve an ACL from the server */
struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
struct inode *inode, const char *path,
u32 *pacllen)
{
struct cifs_ntsd *pntsd = NULL;
struct cifsFileInfo *open_file = NULL;
if (inode)
open_file = find_readable_file(CIFS_I(inode), true);
if (!open_file)
return get_cifs_acl_by_path(cifs_sb, path, pacllen);
pntsd = get_cifs_acl_by_fid(cifs_sb, &open_file->fid, pacllen);
cifsFileInfo_put(open_file);
return pntsd;
}
/* Set an ACL on the server */
int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
struct inode *inode, const char *path, int aclflag)
{
int oplock = 0;
unsigned int xid;
int rc, access_flags, create_options = 0;
struct cifs_tcon *tcon;
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
struct cifs_fid fid;
struct cifs_open_parms oparms;
if (IS_ERR(tlink))
return PTR_ERR(tlink);
tcon = tlink_tcon(tlink);
xid = get_xid();
if (backup_cred(cifs_sb))
create_options |= CREATE_OPEN_BACKUP_INTENT;
if (aclflag == CIFS_ACL_OWNER || aclflag == CIFS_ACL_GROUP)
access_flags = WRITE_OWNER;
else
access_flags = WRITE_DAC;
oparms.tcon = tcon;
oparms.cifs_sb = cifs_sb;
oparms.desired_access = access_flags;
oparms.create_options = create_options;
oparms.disposition = FILE_OPEN;
oparms.path = path;
oparms.fid = &fid;
oparms.reconnect = false;
rc = CIFS_open(xid, &oparms, &oplock, NULL);
if (rc) {
cifs_dbg(VFS, "Unable to open file to set ACL\n");
goto out;
}
rc = CIFSSMBSetCIFSACL(xid, tcon, fid.netfid, pnntsd, acllen, aclflag);
cifs_dbg(NOISY, "SetCIFSACL rc = %d\n", rc);
CIFSSMBClose(xid, tcon, fid.netfid);
out:
free_xid(xid);