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9#include <linux/types.h>
10#include <linux/slab.h>
11#include <linux/fs.h>
12#include <linux/sched.h>
13#include "smack.h"
14
15struct smack_known smack_known_huh = {
16 .smk_known = "?",
17 .smk_secid = 2,
18};
19
20struct smack_known smack_known_hat = {
21 .smk_known = "^",
22 .smk_secid = 3,
23};
24
25struct smack_known smack_known_star = {
26 .smk_known = "*",
27 .smk_secid = 4,
28};
29
30struct smack_known smack_known_floor = {
31 .smk_known = "_",
32 .smk_secid = 5,
33};
34
35struct smack_known smack_known_web = {
36 .smk_known = "@",
37 .smk_secid = 7,
38};
39
40LIST_HEAD(smack_known_list);
41
42
43
44
45
46static u32 smack_next_secid = 10;
47
48
49
50
51
52int log_policy = SMACK_AUDIT_DENIED;
53
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80
81int smk_access_entry(char *subject_label, char *object_label,
82 struct list_head *rule_list)
83{
84 struct smack_rule *srp;
85
86 list_for_each_entry_rcu(srp, rule_list, list) {
87 if (srp->smk_object->smk_known == object_label &&
88 srp->smk_subject->smk_known == subject_label) {
89 int may = srp->smk_access;
90
91
92
93 if ((may & MAY_WRITE) == MAY_WRITE)
94 may |= MAY_LOCK;
95 return may;
96 }
97 }
98
99 return -ENOENT;
100}
101
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113
114
115int smk_access(struct smack_known *subject, struct smack_known *object,
116 int request, struct smk_audit_info *a)
117{
118 int may = MAY_NOT;
119 int rc = 0;
120
121
122
123
124
125
126
127 if (subject == &smack_known_star) {
128 rc = -EACCES;
129 goto out_audit;
130 }
131
132
133
134
135
136 if (object == &smack_known_web || subject == &smack_known_web)
137 goto out_audit;
138
139
140
141 if (object == &smack_known_star)
142 goto out_audit;
143
144
145
146
147 if (subject->smk_known == object->smk_known)
148 goto out_audit;
149
150
151
152
153 if ((request & MAY_ANYREAD) == request ||
154 (request & MAY_LOCK) == request) {
155 if (object == &smack_known_floor)
156 goto out_audit;
157 if (subject == &smack_known_hat)
158 goto out_audit;
159 }
160
161
162
163
164
165
166
167 rcu_read_lock();
168 may = smk_access_entry(subject->smk_known, object->smk_known,
169 &subject->smk_rules);
170 rcu_read_unlock();
171
172 if (may <= 0 || (request & may) != request) {
173 rc = -EACCES;
174 goto out_audit;
175 }
176#ifdef CONFIG_SECURITY_SMACK_BRINGUP
177
178
179
180
181
182 if (may & MAY_BRINGUP)
183 rc = SMACK_BRINGUP_ALLOW;
184#endif
185
186out_audit:
187
188#ifdef CONFIG_SECURITY_SMACK_BRINGUP
189 if (rc < 0) {
190 if (object == smack_unconfined)
191 rc = SMACK_UNCONFINED_OBJECT;
192 if (subject == smack_unconfined)
193 rc = SMACK_UNCONFINED_SUBJECT;
194 }
195#endif
196
197#ifdef CONFIG_AUDIT
198 if (a)
199 smack_log(subject->smk_known, object->smk_known,
200 request, rc, a);
201#endif
202
203 return rc;
204}
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216
217
218int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
219 u32 mode, struct smk_audit_info *a)
220{
221 struct smack_known *sbj_known = smk_of_task(tsp);
222 int may;
223 int rc;
224
225
226
227
228 rc = smk_access(sbj_known, obj_known, mode, NULL);
229 if (rc >= 0) {
230
231
232
233
234 may = smk_access_entry(sbj_known->smk_known,
235 obj_known->smk_known,
236 &tsp->smk_rules);
237 if (may < 0)
238 goto out_audit;
239 if ((mode & may) == mode)
240 goto out_audit;
241 rc = -EACCES;
242 }
243
244
245
246
247 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
248 rc = 0;
249
250out_audit:
251#ifdef CONFIG_AUDIT
252 if (a)
253 smack_log(sbj_known->smk_known, obj_known->smk_known,
254 mode, rc, a);
255#endif
256 return rc;
257}
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269
270int smk_curacc(struct smack_known *obj_known,
271 u32 mode, struct smk_audit_info *a)
272{
273 struct task_smack *tsp = smack_cred(current_cred());
274
275 return smk_tskacc(tsp, obj_known, mode, a);
276}
277
278#ifdef CONFIG_AUDIT
279
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284
285
286static inline void smack_str_from_perm(char *string, int access)
287{
288 int i = 0;
289
290 if (access & MAY_READ)
291 string[i++] = 'r';
292 if (access & MAY_WRITE)
293 string[i++] = 'w';
294 if (access & MAY_EXEC)
295 string[i++] = 'x';
296 if (access & MAY_APPEND)
297 string[i++] = 'a';
298 if (access & MAY_TRANSMUTE)
299 string[i++] = 't';
300 if (access & MAY_LOCK)
301 string[i++] = 'l';
302 string[i] = '\0';
303}
304
305
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309
310
311static void smack_log_callback(struct audit_buffer *ab, void *a)
312{
313 struct common_audit_data *ad = a;
314 struct smack_audit_data *sad = ad->smack_audit_data;
315 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
316 ad->smack_audit_data->function,
317 sad->result ? "denied" : "granted");
318 audit_log_format(ab, " subject=");
319 audit_log_untrustedstring(ab, sad->subject);
320 audit_log_format(ab, " object=");
321 audit_log_untrustedstring(ab, sad->object);
322 if (sad->request[0] == '\0')
323 audit_log_format(ab, " labels_differ");
324 else
325 audit_log_format(ab, " requested=%s", sad->request);
326}
327
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338
339void smack_log(char *subject_label, char *object_label, int request,
340 int result, struct smk_audit_info *ad)
341{
342#ifdef CONFIG_SECURITY_SMACK_BRINGUP
343 char request_buffer[SMK_NUM_ACCESS_TYPE + 5];
344#else
345 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
346#endif
347 struct smack_audit_data *sad;
348 struct common_audit_data *a = &ad->a;
349
350
351 if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
352 return;
353 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
354 return;
355
356 sad = a->smack_audit_data;
357
358 if (sad->function == NULL)
359 sad->function = "unknown";
360
361
362 smack_str_from_perm(request_buffer, request);
363 sad->subject = subject_label;
364 sad->object = object_label;
365#ifdef CONFIG_SECURITY_SMACK_BRINGUP
366
367
368
369
370
371
372 if (result == SMACK_UNCONFINED_SUBJECT)
373 strcat(request_buffer, "(US)");
374 else if (result == SMACK_UNCONFINED_OBJECT)
375 strcat(request_buffer, "(UO)");
376
377 if (result > 0)
378 result = 0;
379#endif
380 sad->request = request_buffer;
381 sad->result = result;
382
383 common_lsm_audit(a, smack_log_callback, NULL);
384}
385#else
386void smack_log(char *subject_label, char *object_label, int request,
387 int result, struct smk_audit_info *ad)
388{
389}
390#endif
391
392DEFINE_MUTEX(smack_known_lock);
393
394struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
395
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401
402void smk_insert_entry(struct smack_known *skp)
403{
404 unsigned int hash;
405 struct hlist_head *head;
406
407 hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
408 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
409
410 hlist_add_head_rcu(&skp->smk_hashed, head);
411 list_add_rcu(&skp->list, &smack_known_list);
412}
413
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420
421struct smack_known *smk_find_entry(const char *string)
422{
423 unsigned int hash;
424 struct hlist_head *head;
425 struct smack_known *skp;
426
427 hash = full_name_hash(NULL, string, strlen(string));
428 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
429
430 hlist_for_each_entry_rcu(skp, head, smk_hashed)
431 if (strcmp(skp->smk_known, string) == 0)
432 return skp;
433
434 return NULL;
435}
436
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443
444char *smk_parse_smack(const char *string, int len)
445{
446 char *smack;
447 int i;
448
449 if (len <= 0)
450 len = strlen(string) + 1;
451
452
453
454
455
456
457 if (string[0] == '-')
458 return ERR_PTR(-EINVAL);
459
460 for (i = 0; i < len; i++)
461 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
462 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
463 break;
464
465 if (i == 0 || i >= SMK_LONGLABEL)
466 return ERR_PTR(-EINVAL);
467
468 smack = kzalloc(i + 1, GFP_NOFS);
469 if (smack == NULL)
470 return ERR_PTR(-ENOMEM);
471
472 strncpy(smack, string, i);
473
474 return smack;
475}
476
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486
487int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
488 int len)
489{
490 unsigned char *cp;
491 unsigned char m;
492 int cat;
493 int rc;
494 int byte;
495
496 sap->flags |= NETLBL_SECATTR_MLS_CAT;
497 sap->attr.mls.lvl = level;
498 sap->attr.mls.cat = NULL;
499
500 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
501 for (m = 0x80; m != 0; m >>= 1, cat++) {
502 if ((m & *cp) == 0)
503 continue;
504 rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
505 cat, GFP_NOFS);
506 if (rc < 0) {
507 netlbl_catmap_free(sap->attr.mls.cat);
508 return rc;
509 }
510 }
511
512 return 0;
513}
514
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518
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521
522
523int smack_populate_secattr(struct smack_known *skp)
524{
525 int slen;
526
527 skp->smk_netlabel.attr.secid = skp->smk_secid;
528 skp->smk_netlabel.domain = skp->smk_known;
529 skp->smk_netlabel.cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
530 if (skp->smk_netlabel.cache != NULL) {
531 skp->smk_netlabel.flags |= NETLBL_SECATTR_CACHE;
532 skp->smk_netlabel.cache->free = NULL;
533 skp->smk_netlabel.cache->data = skp;
534 }
535 skp->smk_netlabel.flags |= NETLBL_SECATTR_SECID |
536 NETLBL_SECATTR_MLS_LVL |
537 NETLBL_SECATTR_DOMAIN;
538
539
540
541
542 slen = strlen(skp->smk_known);
543 if (slen < SMK_CIPSOLEN)
544 return smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
545 &skp->smk_netlabel, slen);
546
547 return smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
548 &skp->smk_netlabel, sizeof(skp->smk_secid));
549}
550
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559
560struct smack_known *smk_import_entry(const char *string, int len)
561{
562 struct smack_known *skp;
563 char *smack;
564 int rc;
565
566 smack = smk_parse_smack(string, len);
567 if (IS_ERR(smack))
568 return ERR_CAST(smack);
569
570 mutex_lock(&smack_known_lock);
571
572 skp = smk_find_entry(smack);
573 if (skp != NULL)
574 goto freeout;
575
576 skp = kzalloc(sizeof(*skp), GFP_NOFS);
577 if (skp == NULL) {
578 skp = ERR_PTR(-ENOMEM);
579 goto freeout;
580 }
581
582 skp->smk_known = smack;
583 skp->smk_secid = smack_next_secid++;
584
585 rc = smack_populate_secattr(skp);
586 if (rc >= 0) {
587 INIT_LIST_HEAD(&skp->smk_rules);
588 mutex_init(&skp->smk_rules_lock);
589
590
591
592
593 smk_insert_entry(skp);
594 goto unlockout;
595 }
596 kfree(skp);
597 skp = ERR_PTR(rc);
598freeout:
599 kfree(smack);
600unlockout:
601 mutex_unlock(&smack_known_lock);
602
603 return skp;
604}
605
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608
609
610
611
612
613struct smack_known *smack_from_secid(const u32 secid)
614{
615 struct smack_known *skp;
616
617 rcu_read_lock();
618 list_for_each_entry_rcu(skp, &smack_known_list, list) {
619 if (skp->smk_secid == secid) {
620 rcu_read_unlock();
621 return skp;
622 }
623 }
624
625
626
627
628
629 rcu_read_unlock();
630 return &smack_known_huh;
631}
632
633
634
635
636
637
638
639
640LIST_HEAD(smack_onlycap_list);
641DEFINE_MUTEX(smack_onlycap_lock);
642
643
644
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650
651
652
653bool smack_privileged_cred(int cap, const struct cred *cred)
654{
655 struct task_smack *tsp = smack_cred(cred);
656 struct smack_known *skp = tsp->smk_task;
657 struct smack_known_list_elem *sklep;
658 int rc;
659
660 rc = cap_capable(cred, &init_user_ns, cap, CAP_OPT_NONE);
661 if (rc)
662 return false;
663
664 rcu_read_lock();
665 if (list_empty(&smack_onlycap_list)) {
666 rcu_read_unlock();
667 return true;
668 }
669
670 list_for_each_entry_rcu(sklep, &smack_onlycap_list, list) {
671 if (sklep->smk_label == skp) {
672 rcu_read_unlock();
673 return true;
674 }
675 }
676 rcu_read_unlock();
677
678 return false;
679}
680
681
682
683
684
685
686
687
688
689
690bool smack_privileged(int cap)
691{
692
693
694
695 if (unlikely(current->flags & PF_KTHREAD))
696 return true;
697
698 return smack_privileged_cred(cap, current_cred());
699}
700