-
Notifications
You must be signed in to change notification settings - Fork 102
/
smack_lsm.c
5183 lines (4597 loc) · 126 KB
/
smack_lsm.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
// SPDX-License-Identifier: GPL-2.0-only
/*
* Simplified MAC Kernel (smack) security module
*
* This file contains the smack hook function implementations.
*
* Authors:
* Casey Schaufler <casey@schaufler-ca.com>
* Jarkko Sakkinen <jarkko.sakkinen@intel.com>
*
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul@paul-moore.com>
* Copyright (C) 2010 Nokia Corporation
* Copyright (C) 2011 Intel Corporation.
*/
#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/icmpv6.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <net/cipso_ipv4.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/audit.h>
#include <linux/magic.h>
#include <linux/dcache.h>
#include <linux/personality.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/binfmts.h>
#include <linux/parser.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/watch_queue.h>
#include <linux/io_uring.h>
#include "smack.h"
#define TRANS_TRUE "TRUE"
#define TRANS_TRUE_SIZE 4
#define SMK_CONNECTING 0
#define SMK_RECEIVING 1
#define SMK_SENDING 2
/*
* Smack uses multiple xattrs.
* SMACK64 - for access control,
* SMACK64TRANSMUTE - label initialization,
* Not saved on files - SMACK64IPIN and SMACK64IPOUT,
* Must be set explicitly - SMACK64EXEC and SMACK64MMAP
*/
#define SMACK_INODE_INIT_XATTRS 2
#ifdef SMACK_IPV6_PORT_LABELING
static DEFINE_MUTEX(smack_ipv6_lock);
static LIST_HEAD(smk_ipv6_port_list);
#endif
struct kmem_cache *smack_rule_cache;
int smack_enabled __initdata;
#define A(s) {"smack"#s, sizeof("smack"#s) - 1, Opt_##s}
static struct {
const char *name;
int len;
int opt;
} smk_mount_opts[] = {
{"smackfsdef", sizeof("smackfsdef") - 1, Opt_fsdefault},
A(fsdefault), A(fsfloor), A(fshat), A(fsroot), A(fstransmute)
};
#undef A
static int match_opt_prefix(char *s, int l, char **arg)
{
int i;
for (i = 0; i < ARRAY_SIZE(smk_mount_opts); i++) {
size_t len = smk_mount_opts[i].len;
if (len > l || memcmp(s, smk_mount_opts[i].name, len))
continue;
if (len == l || s[len] != '=')
continue;
*arg = s + len + 1;
return smk_mount_opts[i].opt;
}
return Opt_error;
}
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static char *smk_bu_mess[] = {
"Bringup Error", /* Unused */
"Bringup", /* SMACK_BRINGUP_ALLOW */
"Unconfined Subject", /* SMACK_UNCONFINED_SUBJECT */
"Unconfined Object", /* SMACK_UNCONFINED_OBJECT */
};
static void smk_bu_mode(int mode, char *s)
{
int i = 0;
if (mode & MAY_READ)
s[i++] = 'r';
if (mode & MAY_WRITE)
s[i++] = 'w';
if (mode & MAY_EXEC)
s[i++] = 'x';
if (mode & MAY_APPEND)
s[i++] = 'a';
if (mode & MAY_TRANSMUTE)
s[i++] = 't';
if (mode & MAY_LOCK)
s[i++] = 'l';
if (i == 0)
s[i++] = '-';
s[i] = '\0';
}
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_note(char *note, struct smack_known *sskp,
struct smack_known *oskp, int mode, int rc)
{
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) %s\n", smk_bu_mess[rc],
sskp->smk_known, oskp->smk_known, acc, note);
return 0;
}
#else
#define smk_bu_note(note, sskp, oskp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_current(char *note, struct smack_known *oskp,
int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) %s %s\n", smk_bu_mess[rc],
tsp->smk_task->smk_known, oskp->smk_known,
acc, current->comm, note);
return 0;
}
#else
#define smk_bu_current(note, oskp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_task(struct task_struct *otp, int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
struct smack_known *smk_task = smk_of_task_struct_obj(otp);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) %s to %s\n", smk_bu_mess[rc],
tsp->smk_task->smk_known, smk_task->smk_known, acc,
current->comm, otp->comm);
return 0;
}
#else
#define smk_bu_task(otp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_inode(struct inode *inode, int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
struct inode_smack *isp = smack_inode(inode);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (isp->smk_flags & SMK_INODE_IMPURE)
pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
inode->i_sb->s_id, inode->i_ino, current->comm);
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
if (rc == SMACK_UNCONFINED_SUBJECT &&
(mode & (MAY_WRITE | MAY_APPEND)))
isp->smk_flags |= SMK_INODE_IMPURE;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) inode=(%s %ld) %s\n", smk_bu_mess[rc],
tsp->smk_task->smk_known, isp->smk_inode->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, current->comm);
return 0;
}
#else
#define smk_bu_inode(inode, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_file(struct file *file, int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
struct smack_known *sskp = tsp->smk_task;
struct inode *inode = file_inode(file);
struct inode_smack *isp = smack_inode(inode);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (isp->smk_flags & SMK_INODE_IMPURE)
pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
inode->i_sb->s_id, inode->i_ino, current->comm);
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, file,
current->comm);
return 0;
}
#else
#define smk_bu_file(file, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_credfile(const struct cred *cred, struct file *file,
int mode, int rc)
{
struct task_smack *tsp = smack_cred(cred);
struct smack_known *sskp = tsp->smk_task;
struct inode *inode = file_inode(file);
struct inode_smack *isp = smack_inode(inode);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (isp->smk_flags & SMK_INODE_IMPURE)
pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
inode->i_sb->s_id, inode->i_ino, current->comm);
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, file,
current->comm);
return 0;
}
#else
#define smk_bu_credfile(cred, file, mode, RC) (RC)
#endif
/**
* smk_fetch - Fetch the smack label from a file.
* @name: type of the label (attribute)
* @ip: a pointer to the inode
* @dp: a pointer to the dentry
*
* Returns a pointer to the master list entry for the Smack label,
* NULL if there was no label to fetch, or an error code.
*/
static struct smack_known *smk_fetch(const char *name, struct inode *ip,
struct dentry *dp)
{
int rc;
char *buffer;
struct smack_known *skp = NULL;
if (!(ip->i_opflags & IOP_XATTR))
return ERR_PTR(-EOPNOTSUPP);
buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS);
if (buffer == NULL)
return ERR_PTR(-ENOMEM);
rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
if (rc < 0)
skp = ERR_PTR(rc);
else if (rc == 0)
skp = NULL;
else
skp = smk_import_entry(buffer, rc);
kfree(buffer);
return skp;
}
/**
* init_inode_smack - initialize an inode security blob
* @inode: inode to extract the info from
* @skp: a pointer to the Smack label entry to use in the blob
*
*/
static void init_inode_smack(struct inode *inode, struct smack_known *skp)
{
struct inode_smack *isp = smack_inode(inode);
isp->smk_inode = skp;
isp->smk_flags = 0;
}
/**
* init_task_smack - initialize a task security blob
* @tsp: blob to initialize
* @task: a pointer to the Smack label for the running task
* @forked: a pointer to the Smack label for the forked task
*
*/
static void init_task_smack(struct task_smack *tsp, struct smack_known *task,
struct smack_known *forked)
{
tsp->smk_task = task;
tsp->smk_forked = forked;
INIT_LIST_HEAD(&tsp->smk_rules);
INIT_LIST_HEAD(&tsp->smk_relabel);
mutex_init(&tsp->smk_rules_lock);
}
/**
* smk_copy_rules - copy a rule set
* @nhead: new rules header pointer
* @ohead: old rules header pointer
* @gfp: type of the memory for the allocation
*
* Returns 0 on success, -ENOMEM on error
*/
static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
gfp_t gfp)
{
struct smack_rule *nrp;
struct smack_rule *orp;
int rc = 0;
list_for_each_entry_rcu(orp, ohead, list) {
nrp = kmem_cache_zalloc(smack_rule_cache, gfp);
if (nrp == NULL) {
rc = -ENOMEM;
break;
}
*nrp = *orp;
list_add_rcu(&nrp->list, nhead);
}
return rc;
}
/**
* smk_copy_relabel - copy smk_relabel labels list
* @nhead: new rules header pointer
* @ohead: old rules header pointer
* @gfp: type of the memory for the allocation
*
* Returns 0 on success, -ENOMEM on error
*/
static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead,
gfp_t gfp)
{
struct smack_known_list_elem *nklep;
struct smack_known_list_elem *oklep;
list_for_each_entry(oklep, ohead, list) {
nklep = kzalloc(sizeof(struct smack_known_list_elem), gfp);
if (nklep == NULL) {
smk_destroy_label_list(nhead);
return -ENOMEM;
}
nklep->smk_label = oklep->smk_label;
list_add(&nklep->list, nhead);
}
return 0;
}
/**
* smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
* @mode: input mode in form of PTRACE_MODE_*
*
* Returns a converted MAY_* mode usable by smack rules
*/
static inline unsigned int smk_ptrace_mode(unsigned int mode)
{
if (mode & PTRACE_MODE_ATTACH)
return MAY_READWRITE;
if (mode & PTRACE_MODE_READ)
return MAY_READ;
return 0;
}
/**
* smk_ptrace_rule_check - helper for ptrace access
* @tracer: tracer process
* @tracee_known: label entry of the process that's about to be traced
* @mode: ptrace attachment mode (PTRACE_MODE_*)
* @func: name of the function that called us, used for audit
*
* Returns 0 on access granted, -error on error
*/
static int smk_ptrace_rule_check(struct task_struct *tracer,
struct smack_known *tracee_known,
unsigned int mode, const char *func)
{
int rc;
struct smk_audit_info ad, *saip = NULL;
struct task_smack *tsp;
struct smack_known *tracer_known;
const struct cred *tracercred;
if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, tracer);
saip = &ad;
}
rcu_read_lock();
tracercred = __task_cred(tracer);
tsp = smack_cred(tracercred);
tracer_known = smk_of_task(tsp);
if ((mode & PTRACE_MODE_ATTACH) &&
(smack_ptrace_rule == SMACK_PTRACE_EXACT ||
smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
if (tracer_known->smk_known == tracee_known->smk_known)
rc = 0;
else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
rc = -EACCES;
else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))
rc = 0;
else
rc = -EACCES;
if (saip)
smack_log(tracer_known->smk_known,
tracee_known->smk_known,
0, rc, saip);
rcu_read_unlock();
return rc;
}
/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
rcu_read_unlock();
return rc;
}
/*
* LSM hooks.
* We he, that is fun!
*/
/**
* smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
* @ctp: child task pointer
* @mode: ptrace attachment mode (PTRACE_MODE_*)
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks.
*/
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
struct smack_known *skp;
skp = smk_of_task_struct_obj(ctp);
return smk_ptrace_rule_check(current, skp, mode, __func__);
}
/**
* smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
* @ptp: parent task pointer
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks, and require PTRACE_MODE_ATTACH.
*/
static int smack_ptrace_traceme(struct task_struct *ptp)
{
struct smack_known *skp;
skp = smk_of_task(smack_cred(current_cred()));
return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
}
/**
* smack_syslog - Smack approval on syslog
* @typefrom_file: unused
*
* Returns 0 on success, error code otherwise.
*/
static int smack_syslog(int typefrom_file)
{
int rc = 0;
struct smack_known *skp = smk_of_current();
if (smack_privileged(CAP_MAC_OVERRIDE))
return 0;
if (smack_syslog_label != NULL && smack_syslog_label != skp)
rc = -EACCES;
return rc;
}
/*
* Superblock Hooks.
*/
/**
* smack_sb_alloc_security - allocate a superblock blob
* @sb: the superblock getting the blob
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_sb_alloc_security(struct super_block *sb)
{
struct superblock_smack *sbsp = smack_superblock(sb);
sbsp->smk_root = &smack_known_floor;
sbsp->smk_default = &smack_known_floor;
sbsp->smk_floor = &smack_known_floor;
sbsp->smk_hat = &smack_known_hat;
/*
* SMK_SB_INITIALIZED will be zero from kzalloc.
*/
return 0;
}
struct smack_mnt_opts {
const char *fsdefault;
const char *fsfloor;
const char *fshat;
const char *fsroot;
const char *fstransmute;
};
static void smack_free_mnt_opts(void *mnt_opts)
{
kfree(mnt_opts);
}
static int smack_add_opt(int token, const char *s, void **mnt_opts)
{
struct smack_mnt_opts *opts = *mnt_opts;
struct smack_known *skp;
if (!opts) {
opts = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
if (!opts)
return -ENOMEM;
*mnt_opts = opts;
}
if (!s)
return -ENOMEM;
skp = smk_import_entry(s, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
switch (token) {
case Opt_fsdefault:
if (opts->fsdefault)
goto out_opt_err;
opts->fsdefault = skp->smk_known;
break;
case Opt_fsfloor:
if (opts->fsfloor)
goto out_opt_err;
opts->fsfloor = skp->smk_known;
break;
case Opt_fshat:
if (opts->fshat)
goto out_opt_err;
opts->fshat = skp->smk_known;
break;
case Opt_fsroot:
if (opts->fsroot)
goto out_opt_err;
opts->fsroot = skp->smk_known;
break;
case Opt_fstransmute:
if (opts->fstransmute)
goto out_opt_err;
opts->fstransmute = skp->smk_known;
break;
}
return 0;
out_opt_err:
pr_warn("Smack: duplicate mount options\n");
return -EINVAL;
}
/**
* smack_fs_context_submount - Initialise security data for a filesystem context
* @fc: The filesystem context.
* @reference: reference superblock
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_fs_context_submount(struct fs_context *fc,
struct super_block *reference)
{
struct superblock_smack *sbsp;
struct smack_mnt_opts *ctx;
struct inode_smack *isp;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
fc->security = ctx;
sbsp = smack_superblock(reference);
isp = smack_inode(reference->s_root->d_inode);
if (sbsp->smk_default) {
ctx->fsdefault = kstrdup(sbsp->smk_default->smk_known, GFP_KERNEL);
if (!ctx->fsdefault)
return -ENOMEM;
}
if (sbsp->smk_floor) {
ctx->fsfloor = kstrdup(sbsp->smk_floor->smk_known, GFP_KERNEL);
if (!ctx->fsfloor)
return -ENOMEM;
}
if (sbsp->smk_hat) {
ctx->fshat = kstrdup(sbsp->smk_hat->smk_known, GFP_KERNEL);
if (!ctx->fshat)
return -ENOMEM;
}
if (isp->smk_flags & SMK_INODE_TRANSMUTE) {
if (sbsp->smk_root) {
ctx->fstransmute = kstrdup(sbsp->smk_root->smk_known, GFP_KERNEL);
if (!ctx->fstransmute)
return -ENOMEM;
}
}
return 0;
}
/**
* smack_fs_context_dup - Duplicate the security data on fs_context duplication
* @fc: The new filesystem context.
* @src_fc: The source filesystem context being duplicated.
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc)
{
struct smack_mnt_opts *dst, *src = src_fc->security;
if (!src)
return 0;
fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
if (!fc->security)
return -ENOMEM;
dst = fc->security;
dst->fsdefault = src->fsdefault;
dst->fsfloor = src->fsfloor;
dst->fshat = src->fshat;
dst->fsroot = src->fsroot;
dst->fstransmute = src->fstransmute;
return 0;
}
static const struct fs_parameter_spec smack_fs_parameters[] = {
fsparam_string("smackfsdef", Opt_fsdefault),
fsparam_string("smackfsdefault", Opt_fsdefault),
fsparam_string("smackfsfloor", Opt_fsfloor),
fsparam_string("smackfshat", Opt_fshat),
fsparam_string("smackfsroot", Opt_fsroot),
fsparam_string("smackfstransmute", Opt_fstransmute),
{}
};
/**
* smack_fs_context_parse_param - Parse a single mount parameter
* @fc: The new filesystem context being constructed.
* @param: The parameter.
*
* Returns 0 on success, -ENOPARAM to pass the parameter on or anything else on
* error.
*/
static int smack_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
struct fs_parse_result result;
int opt, rc;
opt = fs_parse(fc, smack_fs_parameters, param, &result);
if (opt < 0)
return opt;
rc = smack_add_opt(opt, param->string, &fc->security);
if (!rc)
param->string = NULL;
return rc;
}
static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
{
char *from = options, *to = options;
bool first = true;
while (1) {
char *next = strchr(from, ',');
int token, len, rc;
char *arg = NULL;
if (next)
len = next - from;
else
len = strlen(from);
token = match_opt_prefix(from, len, &arg);
if (token != Opt_error) {
arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
rc = smack_add_opt(token, arg, mnt_opts);
kfree(arg);
if (unlikely(rc)) {
if (*mnt_opts)
smack_free_mnt_opts(*mnt_opts);
*mnt_opts = NULL;
return rc;
}
} else {
if (!first) { // copy with preceding comma
from--;
len++;
}
if (to != from)
memmove(to, from, len);
to += len;
first = false;
}
if (!from[len])
break;
from += len + 1;
}
*to = '\0';
return 0;
}
/**
* smack_set_mnt_opts - set Smack specific mount options
* @sb: the file system superblock
* @mnt_opts: Smack mount options
* @kern_flags: mount option from kernel space or user space
* @set_kern_flags: where to store converted mount opts
*
* Returns 0 on success, an error code on failure
*
* Allow filesystems with binary mount data to explicitly set Smack mount
* labels.
*/
static int smack_set_mnt_opts(struct super_block *sb,
void *mnt_opts,
unsigned long kern_flags,
unsigned long *set_kern_flags)
{
struct dentry *root = sb->s_root;
struct inode *inode = d_backing_inode(root);
struct superblock_smack *sp = smack_superblock(sb);
struct inode_smack *isp;
struct smack_known *skp;
struct smack_mnt_opts *opts = mnt_opts;
bool transmute = false;
if (sp->smk_flags & SMK_SB_INITIALIZED)
return 0;
if (!smack_privileged(CAP_MAC_ADMIN)) {
/*
* Unprivileged mounts don't get to specify Smack values.
*/
if (opts)
return -EPERM;
/*
* Unprivileged mounts get root and default from the caller.
*/
skp = smk_of_current();
sp->smk_root = skp;
sp->smk_default = skp;
/*
* For a handful of fs types with no user-controlled
* backing store it's okay to trust security labels
* in the filesystem. The rest are untrusted.
*/
if (sb->s_user_ns != &init_user_ns &&
sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
sb->s_magic != RAMFS_MAGIC) {
transmute = true;
sp->smk_flags |= SMK_SB_UNTRUSTED;
}
}
sp->smk_flags |= SMK_SB_INITIALIZED;
if (opts) {
if (opts->fsdefault) {
skp = smk_import_entry(opts->fsdefault, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_default = skp;
}
if (opts->fsfloor) {
skp = smk_import_entry(opts->fsfloor, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_floor = skp;
}
if (opts->fshat) {
skp = smk_import_entry(opts->fshat, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_hat = skp;
}
if (opts->fsroot) {
skp = smk_import_entry(opts->fsroot, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_root = skp;
}
if (opts->fstransmute) {
skp = smk_import_entry(opts->fstransmute, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_root = skp;
transmute = true;
}
}
/*
* Initialize the root inode.
*/
init_inode_smack(inode, sp->smk_root);
if (transmute) {
isp = smack_inode(inode);
isp->smk_flags |= SMK_INODE_TRANSMUTE;
}
return 0;
}
/**
* smack_sb_statfs - Smack check on statfs
* @dentry: identifies the file system in question
*
* Returns 0 if current can read the floor of the filesystem,
* and error code otherwise
*/
static int smack_sb_statfs(struct dentry *dentry)
{
struct superblock_smack *sbp = smack_superblock(dentry->d_sb);
int rc;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
return rc;
}
/*
* BPRM hooks
*/
/**
* smack_bprm_creds_for_exec - Update bprm->cred if needed for exec
* @bprm: the exec information
*
* Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
*/
static int smack_bprm_creds_for_exec(struct linux_binprm *bprm)
{
struct inode *inode = file_inode(bprm->file);
struct task_smack *bsp = smack_cred(bprm->cred);
struct inode_smack *isp;
struct superblock_smack *sbsp;
int rc;
isp = smack_inode(inode);
if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
return 0;
sbsp = smack_superblock(inode->i_sb);
if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
isp->smk_task != sbsp->smk_root)
return 0;
if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
struct task_struct *tracer;
rc = 0;
rcu_read_lock();
tracer = ptrace_parent(current);
if (likely(tracer != NULL))
rc = smk_ptrace_rule_check(tracer,
isp->smk_task,
PTRACE_MODE_ATTACH,
__func__);
rcu_read_unlock();
if (rc != 0)
return rc;
}
if (bprm->unsafe & ~LSM_UNSAFE_PTRACE)
return -EPERM;
bsp->smk_task = isp->smk_task;
bprm->per_clear |= PER_CLEAR_ON_SETID;
/* Decide if this is a secure exec. */
if (bsp->smk_task != bsp->smk_forked)
bprm->secureexec = 1;
return 0;
}
/*
* Inode hooks
*/
/**
* smack_inode_alloc_security - allocate an inode blob
* @inode: the inode in need of a blob
*
* Returns 0
*/
static int smack_inode_alloc_security(struct inode *inode)
{
struct smack_known *skp = smk_of_current();
init_inode_smack(inode, skp);
return 0;
}
/**
* smack_inode_init_security - copy out the smack from an inode
* @inode: the newly created inode
* @dir: containing directory object
* @qstr: unused
* @xattrs: where to put the attributes
* @xattr_count: current number of LSM-provided xattrs (updated)
*
* Returns 0 if it all works out, -ENOMEM if there's no memory
*/
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr,
struct xattr *xattrs, int *xattr_count)
{
struct task_smack *tsp = smack_cred(current_cred());
struct smack_known *skp = smk_of_task(tsp);
struct smack_known *isp = smk_of_inode(inode);
struct smack_known *dsp = smk_of_inode(dir);
struct xattr *xattr = lsm_get_xattr_slot(xattrs, xattr_count);
int may;