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13#include <linux/types.h>
14#include <linux/slab.h>
15#include <linux/fs.h>
16#include <linux/sched.h>
17#include "smack.h"
18
19struct smack_known smack_known_huh = {
20 .smk_known = "?",
21 .smk_secid = 2,
22};
23
24struct smack_known smack_known_hat = {
25 .smk_known = "^",
26 .smk_secid = 3,
27};
28
29struct smack_known smack_known_star = {
30 .smk_known = "*",
31 .smk_secid = 4,
32};
33
34struct smack_known smack_known_floor = {
35 .smk_known = "_",
36 .smk_secid = 5,
37};
38
39struct smack_known smack_known_invalid = {
40 .smk_known = "",
41 .smk_secid = 6,
42};
43
44struct smack_known smack_known_web = {
45 .smk_known = "@",
46 .smk_secid = 7,
47};
48
49LIST_HEAD(smack_known_list);
50
51
52
53
54
55static u32 smack_next_secid = 10;
56
57
58
59
60
61int log_policy = SMACK_AUDIT_DENIED;
62
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89
90int smk_access_entry(char *subject_label, char *object_label,
91 struct list_head *rule_list)
92{
93 int may = -ENOENT;
94 struct smack_rule *srp;
95
96 list_for_each_entry_rcu(srp, rule_list, list) {
97 if (srp->smk_object->smk_known == object_label &&
98 srp->smk_subject->smk_known == subject_label) {
99 may = srp->smk_access;
100 break;
101 }
102 }
103
104
105
106
107 if ((may & MAY_WRITE) == MAY_WRITE)
108 may |= MAY_LOCK;
109 return may;
110}
111
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122
123
124
125int smk_access(struct smack_known *subject, struct smack_known *object,
126 int request, struct smk_audit_info *a)
127{
128 int may = MAY_NOT;
129 int rc = 0;
130
131
132
133
134
135
136
137 if (subject == &smack_known_star) {
138 rc = -EACCES;
139 goto out_audit;
140 }
141
142
143
144
145
146 if (object == &smack_known_web || subject == &smack_known_web)
147 goto out_audit;
148
149
150
151 if (object == &smack_known_star)
152 goto out_audit;
153
154
155
156
157 if (subject->smk_known == object->smk_known)
158 goto out_audit;
159
160
161
162
163 if ((request & MAY_ANYREAD) == request ||
164 (request & MAY_LOCK) == request) {
165 if (object == &smack_known_floor)
166 goto out_audit;
167 if (subject == &smack_known_hat)
168 goto out_audit;
169 }
170
171
172
173
174
175
176
177 rcu_read_lock();
178 may = smk_access_entry(subject->smk_known, object->smk_known,
179 &subject->smk_rules);
180 rcu_read_unlock();
181
182 if (may <= 0 || (request & may) != request) {
183 rc = -EACCES;
184 goto out_audit;
185 }
186#ifdef CONFIG_SECURITY_SMACK_BRINGUP
187
188
189
190
191
192 if (may & MAY_BRINGUP)
193 rc = SMACK_BRINGUP_ALLOW;
194#endif
195
196out_audit:
197
198#ifdef CONFIG_SECURITY_SMACK_BRINGUP
199 if (rc < 0) {
200 if (object == smack_unconfined)
201 rc = SMACK_UNCONFINED_OBJECT;
202 if (subject == smack_unconfined)
203 rc = SMACK_UNCONFINED_SUBJECT;
204 }
205#endif
206
207#ifdef CONFIG_AUDIT
208 if (a)
209 smack_log(subject->smk_known, object->smk_known,
210 request, rc, a);
211#endif
212
213 return rc;
214}
215
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226
227
228int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
229 u32 mode, struct smk_audit_info *a)
230{
231 struct smack_known *sbj_known = smk_of_task(tsp);
232 int may;
233 int rc;
234
235
236
237
238 rc = smk_access(sbj_known, obj_known, mode, NULL);
239 if (rc >= 0) {
240
241
242
243
244 may = smk_access_entry(sbj_known->smk_known,
245 obj_known->smk_known,
246 &tsp->smk_rules);
247 if (may < 0)
248 goto out_audit;
249 if ((mode & may) == mode)
250 goto out_audit;
251 rc = -EACCES;
252 }
253
254
255
256
257 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
258 rc = 0;
259
260out_audit:
261#ifdef CONFIG_AUDIT
262 if (a)
263 smack_log(sbj_known->smk_known, obj_known->smk_known,
264 mode, rc, a);
265#endif
266 return rc;
267}
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279
280int smk_curacc(struct smack_known *obj_known,
281 u32 mode, struct smk_audit_info *a)
282{
283 struct task_smack *tsp = current_security();
284
285 return smk_tskacc(tsp, obj_known, mode, a);
286}
287
288#ifdef CONFIG_AUDIT
289
290
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294
295
296static inline void smack_str_from_perm(char *string, int access)
297{
298 int i = 0;
299
300 if (access & MAY_READ)
301 string[i++] = 'r';
302 if (access & MAY_WRITE)
303 string[i++] = 'w';
304 if (access & MAY_EXEC)
305 string[i++] = 'x';
306 if (access & MAY_APPEND)
307 string[i++] = 'a';
308 if (access & MAY_TRANSMUTE)
309 string[i++] = 't';
310 if (access & MAY_LOCK)
311 string[i++] = 'l';
312 string[i] = '\0';
313}
314
315
316
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318
319
320
321static void smack_log_callback(struct audit_buffer *ab, void *a)
322{
323 struct common_audit_data *ad = a;
324 struct smack_audit_data *sad = ad->smack_audit_data;
325 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
326 ad->smack_audit_data->function,
327 sad->result ? "denied" : "granted");
328 audit_log_format(ab, " subject=");
329 audit_log_untrustedstring(ab, sad->subject);
330 audit_log_format(ab, " object=");
331 audit_log_untrustedstring(ab, sad->object);
332 if (sad->request[0] == '\0')
333 audit_log_format(ab, " labels_differ");
334 else
335 audit_log_format(ab, " requested=%s", sad->request);
336}
337
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347
348
349void smack_log(char *subject_label, char *object_label, int request,
350 int result, struct smk_audit_info *ad)
351{
352#ifdef CONFIG_SECURITY_SMACK_BRINGUP
353 char request_buffer[SMK_NUM_ACCESS_TYPE + 5];
354#else
355 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
356#endif
357 struct smack_audit_data *sad;
358 struct common_audit_data *a = &ad->a;
359
360
361 if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
362 return;
363 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
364 return;
365
366 sad = a->smack_audit_data;
367
368 if (sad->function == NULL)
369 sad->function = "unknown";
370
371
372 smack_str_from_perm(request_buffer, request);
373 sad->subject = subject_label;
374 sad->object = object_label;
375#ifdef CONFIG_SECURITY_SMACK_BRINGUP
376
377
378
379
380
381
382 if (result == SMACK_UNCONFINED_SUBJECT)
383 strcat(request_buffer, "(US)");
384 else if (result == SMACK_UNCONFINED_OBJECT)
385 strcat(request_buffer, "(UO)");
386
387 if (result > 0)
388 result = 0;
389#endif
390 sad->request = request_buffer;
391 sad->result = result;
392
393 common_lsm_audit(a, smack_log_callback, NULL);
394}
395#else
396void smack_log(char *subject_label, char *object_label, int request,
397 int result, struct smk_audit_info *ad)
398{
399}
400#endif
401
402DEFINE_MUTEX(smack_known_lock);
403
404struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
405
406
407
408
409
410
411void smk_insert_entry(struct smack_known *skp)
412{
413 unsigned int hash;
414 struct hlist_head *head;
415
416 hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
417 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
418
419 hlist_add_head_rcu(&skp->smk_hashed, head);
420 list_add_rcu(&skp->list, &smack_known_list);
421}
422
423
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425
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429
430struct smack_known *smk_find_entry(const char *string)
431{
432 unsigned int hash;
433 struct hlist_head *head;
434 struct smack_known *skp;
435
436 hash = full_name_hash(string, strlen(string));
437 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
438
439 hlist_for_each_entry_rcu(skp, head, smk_hashed)
440 if (strcmp(skp->smk_known, string) == 0)
441 return skp;
442
443 return NULL;
444}
445
446
447
448
449
450
451
452
453char *smk_parse_smack(const char *string, int len)
454{
455 char *smack;
456 int i;
457
458 if (len <= 0)
459 len = strlen(string) + 1;
460
461
462
463
464
465
466 if (string[0] == '-')
467 return ERR_PTR(-EINVAL);
468
469 for (i = 0; i < len; i++)
470 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
471 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
472 break;
473
474 if (i == 0 || i >= SMK_LONGLABEL)
475 return ERR_PTR(-EINVAL);
476
477 smack = kzalloc(i + 1, GFP_KERNEL);
478 if (smack == NULL)
479 return ERR_PTR(-ENOMEM);
480
481 strncpy(smack, string, i);
482
483 return smack;
484}
485
486
487
488
489
490
491
492
493
494int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
495 int len)
496{
497 unsigned char *cp;
498 unsigned char m;
499 int cat;
500 int rc;
501 int byte;
502
503 sap->flags |= NETLBL_SECATTR_MLS_CAT;
504 sap->attr.mls.lvl = level;
505 sap->attr.mls.cat = NULL;
506
507 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
508 for (m = 0x80; m != 0; m >>= 1, cat++) {
509 if ((m & *cp) == 0)
510 continue;
511 rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
512 cat, GFP_ATOMIC);
513 if (rc < 0) {
514 netlbl_catmap_free(sap->attr.mls.cat);
515 return rc;
516 }
517 }
518
519 return 0;
520}
521
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525
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528
529
530
531struct smack_known *smk_import_entry(const char *string, int len)
532{
533 struct smack_known *skp;
534 char *smack;
535 int slen;
536 int rc;
537
538 smack = smk_parse_smack(string, len);
539 if (IS_ERR(smack))
540 return ERR_CAST(smack);
541
542 mutex_lock(&smack_known_lock);
543
544 skp = smk_find_entry(smack);
545 if (skp != NULL)
546 goto freeout;
547
548 skp = kzalloc(sizeof(*skp), GFP_KERNEL);
549 if (skp == NULL) {
550 skp = ERR_PTR(-ENOMEM);
551 goto freeout;
552 }
553
554 skp->smk_known = smack;
555 skp->smk_secid = smack_next_secid++;
556 skp->smk_netlabel.domain = skp->smk_known;
557 skp->smk_netlabel.flags =
558 NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
559
560
561
562
563 slen = strlen(smack);
564 if (slen < SMK_CIPSOLEN)
565 rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
566 &skp->smk_netlabel, slen);
567 else
568 rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
569 &skp->smk_netlabel, sizeof(skp->smk_secid));
570
571 if (rc >= 0) {
572 INIT_LIST_HEAD(&skp->smk_rules);
573 mutex_init(&skp->smk_rules_lock);
574
575
576
577
578 smk_insert_entry(skp);
579 goto unlockout;
580 }
581
582
583
584 kfree(skp);
585 skp = ERR_PTR(rc);
586freeout:
587 kfree(smack);
588unlockout:
589 mutex_unlock(&smack_known_lock);
590
591 return skp;
592}
593
594
595
596
597
598
599
600
601struct smack_known *smack_from_secid(const u32 secid)
602{
603 struct smack_known *skp;
604
605 rcu_read_lock();
606 list_for_each_entry_rcu(skp, &smack_known_list, list) {
607 if (skp->smk_secid == secid) {
608 rcu_read_unlock();
609 return skp;
610 }
611 }
612
613
614
615
616
617 rcu_read_unlock();
618 return &smack_known_invalid;
619}
620
621
622
623
624
625
626
627
628LIST_HEAD(smack_onlycap_list);
629DEFINE_MUTEX(smack_onlycap_lock);
630
631
632
633
634
635
636
637int smack_privileged(int cap)
638{
639 struct smack_known *skp = smk_of_current();
640 struct smack_known_list_elem *sklep;
641
642
643
644
645 if (unlikely(current->flags & PF_KTHREAD))
646 return 1;
647
648 if (!capable(cap))
649 return 0;
650
651 rcu_read_lock();
652 if (list_empty(&smack_onlycap_list)) {
653 rcu_read_unlock();
654 return 1;
655 }
656
657 list_for_each_entry_rcu(sklep, &smack_onlycap_list, list) {
658 if (sklep->smk_label == skp) {
659 rcu_read_unlock();
660 return 1;
661 }
662 }
663 rcu_read_unlock();
664
665 return 0;
666}
667