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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Implementation of the multi-level security (MLS) policy.
4 *
5 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
6 */
7/*
8 * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
9 *
10 * Support for enhanced MLS infrastructure.
11 *
12 * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
13 */
14/*
15 * Updated: Hewlett-Packard <paul@paul-moore.com>
16 *
17 * Added support to import/export the MLS label from NetLabel
18 *
19 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
20 */
21
22#include <linux/kernel.h>
23#include <linux/slab.h>
24#include <linux/string.h>
25#include <linux/errno.h>
26#include <net/netlabel.h>
27#include "sidtab.h"
28#include "mls.h"
29#include "policydb.h"
30#include "services.h"
31
32/*
33 * Return the length in bytes for the MLS fields of the
34 * security context string representation of `context'.
35 */
36int mls_compute_context_len(struct policydb *p, struct context *context)
37{
38 int i, l, len, head, prev;
39 char *nm;
40 struct ebitmap *e;
41 struct ebitmap_node *node;
42
43 if (!p->mls_enabled)
44 return 0;
45
46 len = 1; /* for the beginning ":" */
47 for (l = 0; l < 2; l++) {
48 int index_sens = context->range.level[l].sens;
49 len += strlen(sym_name(p, SYM_LEVELS, index_sens - 1));
50
51 /* categories */
52 head = -2;
53 prev = -2;
54 e = &context->range.level[l].cat;
55 ebitmap_for_each_positive_bit(e, node, i) {
56 if (i - prev > 1) {
57 /* one or more negative bits are skipped */
58 if (head != prev) {
59 nm = sym_name(p, SYM_CATS, prev);
60 len += strlen(nm) + 1;
61 }
62 nm = sym_name(p, SYM_CATS, i);
63 len += strlen(nm) + 1;
64 head = i;
65 }
66 prev = i;
67 }
68 if (prev != head) {
69 nm = sym_name(p, SYM_CATS, prev);
70 len += strlen(nm) + 1;
71 }
72 if (l == 0) {
73 if (mls_level_eq(&context->range.level[0],
74 &context->range.level[1]))
75 break;
76 else
77 len++;
78 }
79 }
80
81 return len;
82}
83
84/*
85 * Write the security context string representation of
86 * the MLS fields of `context' into the string `*scontext'.
87 * Update `*scontext' to point to the end of the MLS fields.
88 */
89void mls_sid_to_context(struct policydb *p,
90 struct context *context,
91 char **scontext)
92{
93 char *scontextp, *nm;
94 int i, l, head, prev;
95 struct ebitmap *e;
96 struct ebitmap_node *node;
97
98 if (!p->mls_enabled)
99 return;
100
101 scontextp = *scontext;
102
103 *scontextp = ':';
104 scontextp++;
105
106 for (l = 0; l < 2; l++) {
107 strcpy(scontextp, sym_name(p, SYM_LEVELS,
108 context->range.level[l].sens - 1));
109 scontextp += strlen(scontextp);
110
111 /* categories */
112 head = -2;
113 prev = -2;
114 e = &context->range.level[l].cat;
115 ebitmap_for_each_positive_bit(e, node, i) {
116 if (i - prev > 1) {
117 /* one or more negative bits are skipped */
118 if (prev != head) {
119 if (prev - head > 1)
120 *scontextp++ = '.';
121 else
122 *scontextp++ = ',';
123 nm = sym_name(p, SYM_CATS, prev);
124 strcpy(scontextp, nm);
125 scontextp += strlen(nm);
126 }
127 if (prev < 0)
128 *scontextp++ = ':';
129 else
130 *scontextp++ = ',';
131 nm = sym_name(p, SYM_CATS, i);
132 strcpy(scontextp, nm);
133 scontextp += strlen(nm);
134 head = i;
135 }
136 prev = i;
137 }
138
139 if (prev != head) {
140 if (prev - head > 1)
141 *scontextp++ = '.';
142 else
143 *scontextp++ = ',';
144 nm = sym_name(p, SYM_CATS, prev);
145 strcpy(scontextp, nm);
146 scontextp += strlen(nm);
147 }
148
149 if (l == 0) {
150 if (mls_level_eq(&context->range.level[0],
151 &context->range.level[1]))
152 break;
153 else
154 *scontextp++ = '-';
155 }
156 }
157
158 *scontext = scontextp;
159}
160
161int mls_level_isvalid(struct policydb *p, struct mls_level *l)
162{
163 struct level_datum *levdatum;
164
165 if (!l->sens || l->sens > p->p_levels.nprim)
166 return 0;
167 levdatum = symtab_search(&p->p_levels,
168 sym_name(p, SYM_LEVELS, l->sens - 1));
169 if (!levdatum)
170 return 0;
171
172 /*
173 * Return 1 iff all the bits set in l->cat are also be set in
174 * levdatum->level->cat and no bit in l->cat is larger than
175 * p->p_cats.nprim.
176 */
177 return ebitmap_contains(&levdatum->level->cat, &l->cat,
178 p->p_cats.nprim);
179}
180
181int mls_range_isvalid(struct policydb *p, struct mls_range *r)
182{
183 return (mls_level_isvalid(p, &r->level[0]) &&
184 mls_level_isvalid(p, &r->level[1]) &&
185 mls_level_dom(&r->level[1], &r->level[0]));
186}
187
188/*
189 * Return 1 if the MLS fields in the security context
190 * structure `c' are valid. Return 0 otherwise.
191 */
192int mls_context_isvalid(struct policydb *p, struct context *c)
193{
194 struct user_datum *usrdatum;
195
196 if (!p->mls_enabled)
197 return 1;
198
199 if (!mls_range_isvalid(p, &c->range))
200 return 0;
201
202 if (c->role == OBJECT_R_VAL)
203 return 1;
204
205 /*
206 * User must be authorized for the MLS range.
207 */
208 if (!c->user || c->user > p->p_users.nprim)
209 return 0;
210 usrdatum = p->user_val_to_struct[c->user - 1];
211 if (!mls_range_contains(usrdatum->range, c->range))
212 return 0; /* user may not be associated with range */
213
214 return 1;
215}
216
217/*
218 * Set the MLS fields in the security context structure
219 * `context' based on the string representation in
220 * the string `scontext'.
221 *
222 * This function modifies the string in place, inserting
223 * NULL characters to terminate the MLS fields.
224 *
225 * If a def_sid is provided and no MLS field is present,
226 * copy the MLS field of the associated default context.
227 * Used for upgraded to MLS systems where objects may lack
228 * MLS fields.
229 *
230 * Policy read-lock must be held for sidtab lookup.
231 *
232 */
233int mls_context_to_sid(struct policydb *pol,
234 char oldc,
235 char *scontext,
236 struct context *context,
237 struct sidtab *s,
238 u32 def_sid)
239{
240 char *sensitivity, *cur_cat, *next_cat, *rngptr;
241 struct level_datum *levdatum;
242 struct cat_datum *catdatum, *rngdatum;
243 int l, rc, i;
244 char *rangep[2];
245
246 if (!pol->mls_enabled) {
247 /*
248 * With no MLS, only return -EINVAL if there is a MLS field
249 * and it did not come from an xattr.
250 */
251 if (oldc && def_sid == SECSID_NULL)
252 return -EINVAL;
253 return 0;
254 }
255
256 /*
257 * No MLS component to the security context, try and map to
258 * default if provided.
259 */
260 if (!oldc) {
261 struct context *defcon;
262
263 if (def_sid == SECSID_NULL)
264 return -EINVAL;
265
266 defcon = sidtab_search(s, def_sid);
267 if (!defcon)
268 return -EINVAL;
269
270 return mls_context_cpy(context, defcon);
271 }
272
273 /*
274 * If we're dealing with a range, figure out where the two parts
275 * of the range begin.
276 */
277 rangep[0] = scontext;
278 rangep[1] = strchr(scontext, '-');
279 if (rangep[1]) {
280 rangep[1][0] = '\0';
281 rangep[1]++;
282 }
283
284 /* For each part of the range: */
285 for (l = 0; l < 2; l++) {
286 /* Split sensitivity and category set. */
287 sensitivity = rangep[l];
288 if (sensitivity == NULL)
289 break;
290 next_cat = strchr(sensitivity, ':');
291 if (next_cat)
292 *(next_cat++) = '\0';
293
294 /* Parse sensitivity. */
295 levdatum = symtab_search(&pol->p_levels, sensitivity);
296 if (!levdatum)
297 return -EINVAL;
298 context->range.level[l].sens = levdatum->level->sens;
299
300 /* Extract category set. */
301 while (next_cat != NULL) {
302 cur_cat = next_cat;
303 next_cat = strchr(next_cat, ',');
304 if (next_cat != NULL)
305 *(next_cat++) = '\0';
306
307 /* Separate into range if exists */
308 rngptr = strchr(cur_cat, '.');
309 if (rngptr != NULL) {
310 /* Remove '.' */
311 *rngptr++ = '\0';
312 }
313
314 catdatum = symtab_search(&pol->p_cats, cur_cat);
315 if (!catdatum)
316 return -EINVAL;
317
318 rc = ebitmap_set_bit(&context->range.level[l].cat,
319 catdatum->value - 1, 1);
320 if (rc)
321 return rc;
322
323 /* If range, set all categories in range */
324 if (rngptr == NULL)
325 continue;
326
327 rngdatum = symtab_search(&pol->p_cats, rngptr);
328 if (!rngdatum)
329 return -EINVAL;
330
331 if (catdatum->value >= rngdatum->value)
332 return -EINVAL;
333
334 for (i = catdatum->value; i < rngdatum->value; i++) {
335 rc = ebitmap_set_bit(&context->range.level[l].cat, i, 1);
336 if (rc)
337 return rc;
338 }
339 }
340 }
341
342 /* If we didn't see a '-', the range start is also the range end. */
343 if (rangep[1] == NULL) {
344 context->range.level[1].sens = context->range.level[0].sens;
345 rc = ebitmap_cpy(&context->range.level[1].cat,
346 &context->range.level[0].cat);
347 if (rc)
348 return rc;
349 }
350
351 return 0;
352}
353
354/*
355 * Set the MLS fields in the security context structure
356 * `context' based on the string representation in
357 * the string `str'. This function will allocate temporary memory with the
358 * given constraints of gfp_mask.
359 */
360int mls_from_string(struct policydb *p, char *str, struct context *context,
361 gfp_t gfp_mask)
362{
363 char *tmpstr;
364 int rc;
365
366 if (!p->mls_enabled)
367 return -EINVAL;
368
369 tmpstr = kstrdup(str, gfp_mask);
370 if (!tmpstr) {
371 rc = -ENOMEM;
372 } else {
373 rc = mls_context_to_sid(p, ':', tmpstr, context,
374 NULL, SECSID_NULL);
375 kfree(tmpstr);
376 }
377
378 return rc;
379}
380
381/*
382 * Copies the MLS range `range' into `context'.
383 */
384int mls_range_set(struct context *context,
385 struct mls_range *range)
386{
387 int l, rc = 0;
388
389 /* Copy the MLS range into the context */
390 for (l = 0; l < 2; l++) {
391 context->range.level[l].sens = range->level[l].sens;
392 rc = ebitmap_cpy(&context->range.level[l].cat,
393 &range->level[l].cat);
394 if (rc)
395 break;
396 }
397
398 return rc;
399}
400
401int mls_setup_user_range(struct policydb *p,
402 struct context *fromcon, struct user_datum *user,
403 struct context *usercon)
404{
405 if (p->mls_enabled) {
406 struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
407 struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
408 struct mls_level *user_low = &(user->range.level[0]);
409 struct mls_level *user_clr = &(user->range.level[1]);
410 struct mls_level *user_def = &(user->dfltlevel);
411 struct mls_level *usercon_sen = &(usercon->range.level[0]);
412 struct mls_level *usercon_clr = &(usercon->range.level[1]);
413
414 /* Honor the user's default level if we can */
415 if (mls_level_between(user_def, fromcon_sen, fromcon_clr))
416 *usercon_sen = *user_def;
417 else if (mls_level_between(fromcon_sen, user_def, user_clr))
418 *usercon_sen = *fromcon_sen;
419 else if (mls_level_between(fromcon_clr, user_low, user_def))
420 *usercon_sen = *user_low;
421 else
422 return -EINVAL;
423
424 /* Lower the clearance of available contexts
425 if the clearance of "fromcon" is lower than
426 that of the user's default clearance (but
427 only if the "fromcon" clearance dominates
428 the user's computed sensitivity level) */
429 if (mls_level_dom(user_clr, fromcon_clr))
430 *usercon_clr = *fromcon_clr;
431 else if (mls_level_dom(fromcon_clr, user_clr))
432 *usercon_clr = *user_clr;
433 else
434 return -EINVAL;
435 }
436
437 return 0;
438}
439
440/*
441 * Convert the MLS fields in the security context
442 * structure `oldc' from the values specified in the
443 * policy `oldp' to the values specified in the policy `newp',
444 * storing the resulting context in `newc'.
445 */
446int mls_convert_context(struct policydb *oldp,
447 struct policydb *newp,
448 struct context *oldc,
449 struct context *newc)
450{
451 struct level_datum *levdatum;
452 struct cat_datum *catdatum;
453 struct ebitmap_node *node;
454 int l, i;
455
456 if (!oldp->mls_enabled || !newp->mls_enabled)
457 return 0;
458
459 for (l = 0; l < 2; l++) {
460 char *name = sym_name(oldp, SYM_LEVELS,
461 oldc->range.level[l].sens - 1);
462
463 levdatum = symtab_search(&newp->p_levels, name);
464
465 if (!levdatum)
466 return -EINVAL;
467 newc->range.level[l].sens = levdatum->level->sens;
468
469 ebitmap_for_each_positive_bit(&oldc->range.level[l].cat,
470 node, i) {
471 int rc;
472
473 catdatum = symtab_search(&newp->p_cats,
474 sym_name(oldp, SYM_CATS, i));
475 if (!catdatum)
476 return -EINVAL;
477 rc = ebitmap_set_bit(&newc->range.level[l].cat,
478 catdatum->value - 1, 1);
479 if (rc)
480 return rc;
481 }
482 }
483
484 return 0;
485}
486
487int mls_compute_sid(struct policydb *p,
488 struct context *scontext,
489 struct context *tcontext,
490 u16 tclass,
491 u32 specified,
492 struct context *newcontext,
493 bool sock)
494{
495 struct range_trans rtr;
496 struct mls_range *r;
497 struct class_datum *cladatum;
498 int default_range = 0;
499
500 if (!p->mls_enabled)
501 return 0;
502
503 switch (specified) {
504 case AVTAB_TRANSITION:
505 /* Look for a range transition rule. */
506 rtr.source_type = scontext->type;
507 rtr.target_type = tcontext->type;
508 rtr.target_class = tclass;
509 r = policydb_rangetr_search(p, &rtr);
510 if (r)
511 return mls_range_set(newcontext, r);
512
513 if (tclass && tclass <= p->p_classes.nprim) {
514 cladatum = p->class_val_to_struct[tclass - 1];
515 if (cladatum)
516 default_range = cladatum->default_range;
517 }
518
519 switch (default_range) {
520 case DEFAULT_SOURCE_LOW:
521 return mls_context_cpy_low(newcontext, scontext);
522 case DEFAULT_SOURCE_HIGH:
523 return mls_context_cpy_high(newcontext, scontext);
524 case DEFAULT_SOURCE_LOW_HIGH:
525 return mls_context_cpy(newcontext, scontext);
526 case DEFAULT_TARGET_LOW:
527 return mls_context_cpy_low(newcontext, tcontext);
528 case DEFAULT_TARGET_HIGH:
529 return mls_context_cpy_high(newcontext, tcontext);
530 case DEFAULT_TARGET_LOW_HIGH:
531 return mls_context_cpy(newcontext, tcontext);
532 case DEFAULT_GLBLUB:
533 return mls_context_glblub(newcontext,
534 scontext, tcontext);
535 }
536
537 fallthrough;
538 case AVTAB_CHANGE:
539 if ((tclass == p->process_class) || sock)
540 /* Use the process MLS attributes. */
541 return mls_context_cpy(newcontext, scontext);
542 else
543 /* Use the process effective MLS attributes. */
544 return mls_context_cpy_low(newcontext, scontext);
545 case AVTAB_MEMBER:
546 /* Use the process effective MLS attributes. */
547 return mls_context_cpy_low(newcontext, scontext);
548 }
549 return -EINVAL;
550}
551
552#ifdef CONFIG_NETLABEL
553/**
554 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
555 * @p: the policy
556 * @context: the security context
557 * @secattr: the NetLabel security attributes
558 *
559 * Description:
560 * Given the security context copy the low MLS sensitivity level into the
561 * NetLabel MLS sensitivity level field.
562 *
563 */
564void mls_export_netlbl_lvl(struct policydb *p,
565 struct context *context,
566 struct netlbl_lsm_secattr *secattr)
567{
568 if (!p->mls_enabled)
569 return;
570
571 secattr->attr.mls.lvl = context->range.level[0].sens - 1;
572 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
573}
574
575/**
576 * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
577 * @p: the policy
578 * @context: the security context
579 * @secattr: the NetLabel security attributes
580 *
581 * Description:
582 * Given the security context and the NetLabel security attributes, copy the
583 * NetLabel MLS sensitivity level into the context.
584 *
585 */
586void mls_import_netlbl_lvl(struct policydb *p,
587 struct context *context,
588 struct netlbl_lsm_secattr *secattr)
589{
590 if (!p->mls_enabled)
591 return;
592
593 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
594 context->range.level[1].sens = context->range.level[0].sens;
595}
596
597/**
598 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
599 * @p: the policy
600 * @context: the security context
601 * @secattr: the NetLabel security attributes
602 *
603 * Description:
604 * Given the security context copy the low MLS categories into the NetLabel
605 * MLS category field. Returns zero on success, negative values on failure.
606 *
607 */
608int mls_export_netlbl_cat(struct policydb *p,
609 struct context *context,
610 struct netlbl_lsm_secattr *secattr)
611{
612 int rc;
613
614 if (!p->mls_enabled)
615 return 0;
616
617 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
618 &secattr->attr.mls.cat);
619 if (rc == 0 && secattr->attr.mls.cat != NULL)
620 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
621
622 return rc;
623}
624
625/**
626 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
627 * @p: the policy
628 * @context: the security context
629 * @secattr: the NetLabel security attributes
630 *
631 * Description:
632 * Copy the NetLabel security attributes into the SELinux context; since the
633 * NetLabel security attribute only contains a single MLS category use it for
634 * both the low and high categories of the context. Returns zero on success,
635 * negative values on failure.
636 *
637 */
638int mls_import_netlbl_cat(struct policydb *p,
639 struct context *context,
640 struct netlbl_lsm_secattr *secattr)
641{
642 int rc;
643
644 if (!p->mls_enabled)
645 return 0;
646
647 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
648 secattr->attr.mls.cat);
649 if (rc)
650 goto import_netlbl_cat_failure;
651 memcpy(&context->range.level[1].cat, &context->range.level[0].cat,
652 sizeof(context->range.level[0].cat));
653
654 return 0;
655
656import_netlbl_cat_failure:
657 ebitmap_destroy(&context->range.level[0].cat);
658 return rc;
659}
660#endif /* CONFIG_NETLABEL */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Implementation of the multi-level security (MLS) policy.
4 *
5 * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
6 */
7
8/*
9 * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
10 * Support for enhanced MLS infrastructure.
11 * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
12 *
13 * Updated: Hewlett-Packard <paul@paul-moore.com>
14 * Added support to import/export the MLS label from NetLabel
15 * Copyright (C) Hewlett-Packard Development Company, L.P., 2006
16 */
17
18#include <linux/kernel.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21#include <linux/errno.h>
22#include <net/netlabel.h>
23#include "sidtab.h"
24#include "mls.h"
25#include "policydb.h"
26#include "services.h"
27
28/*
29 * Return the length in bytes for the MLS fields of the
30 * security context string representation of `context'.
31 */
32int mls_compute_context_len(struct policydb *p, struct context *context)
33{
34 int i, l, len, head, prev;
35 char *nm;
36 struct ebitmap *e;
37 struct ebitmap_node *node;
38
39 if (!p->mls_enabled)
40 return 0;
41
42 len = 1; /* for the beginning ":" */
43 for (l = 0; l < 2; l++) {
44 u32 index_sens = context->range.level[l].sens;
45 len += strlen(sym_name(p, SYM_LEVELS, index_sens - 1));
46
47 /* categories */
48 head = -2;
49 prev = -2;
50 e = &context->range.level[l].cat;
51 ebitmap_for_each_positive_bit(e, node, i)
52 {
53 if (i - prev > 1) {
54 /* one or more negative bits are skipped */
55 if (head != prev) {
56 nm = sym_name(p, SYM_CATS, prev);
57 len += strlen(nm) + 1;
58 }
59 nm = sym_name(p, SYM_CATS, i);
60 len += strlen(nm) + 1;
61 head = i;
62 }
63 prev = i;
64 }
65 if (prev != head) {
66 nm = sym_name(p, SYM_CATS, prev);
67 len += strlen(nm) + 1;
68 }
69 if (l == 0) {
70 if (mls_level_eq(&context->range.level[0],
71 &context->range.level[1]))
72 break;
73 else
74 len++;
75 }
76 }
77
78 return len;
79}
80
81/*
82 * Write the security context string representation of
83 * the MLS fields of `context' into the string `*scontext'.
84 * Update `*scontext' to point to the end of the MLS fields.
85 */
86void mls_sid_to_context(struct policydb *p, struct context *context,
87 char **scontext)
88{
89 char *scontextp, *nm;
90 int i, l, head, prev;
91 struct ebitmap *e;
92 struct ebitmap_node *node;
93
94 if (!p->mls_enabled)
95 return;
96
97 scontextp = *scontext;
98
99 *scontextp = ':';
100 scontextp++;
101
102 for (l = 0; l < 2; l++) {
103 strcpy(scontextp, sym_name(p, SYM_LEVELS,
104 context->range.level[l].sens - 1));
105 scontextp += strlen(scontextp);
106
107 /* categories */
108 head = -2;
109 prev = -2;
110 e = &context->range.level[l].cat;
111 ebitmap_for_each_positive_bit(e, node, i)
112 {
113 if (i - prev > 1) {
114 /* one or more negative bits are skipped */
115 if (prev != head) {
116 if (prev - head > 1)
117 *scontextp++ = '.';
118 else
119 *scontextp++ = ',';
120 nm = sym_name(p, SYM_CATS, prev);
121 strcpy(scontextp, nm);
122 scontextp += strlen(nm);
123 }
124 if (prev < 0)
125 *scontextp++ = ':';
126 else
127 *scontextp++ = ',';
128 nm = sym_name(p, SYM_CATS, i);
129 strcpy(scontextp, nm);
130 scontextp += strlen(nm);
131 head = i;
132 }
133 prev = i;
134 }
135
136 if (prev != head) {
137 if (prev - head > 1)
138 *scontextp++ = '.';
139 else
140 *scontextp++ = ',';
141 nm = sym_name(p, SYM_CATS, prev);
142 strcpy(scontextp, nm);
143 scontextp += strlen(nm);
144 }
145
146 if (l == 0) {
147 if (mls_level_eq(&context->range.level[0],
148 &context->range.level[1]))
149 break;
150 else
151 *scontextp++ = '-';
152 }
153 }
154
155 *scontext = scontextp;
156}
157
158int mls_level_isvalid(struct policydb *p, struct mls_level *l)
159{
160 struct level_datum *levdatum;
161
162 if (!l->sens || l->sens > p->p_levels.nprim)
163 return 0;
164 levdatum = symtab_search(&p->p_levels,
165 sym_name(p, SYM_LEVELS, l->sens - 1));
166 if (!levdatum)
167 return 0;
168
169 /*
170 * Return 1 iff all the bits set in l->cat are also be set in
171 * levdatum->level->cat and no bit in l->cat is larger than
172 * p->p_cats.nprim.
173 */
174 return ebitmap_contains(&levdatum->level->cat, &l->cat,
175 p->p_cats.nprim);
176}
177
178int mls_range_isvalid(struct policydb *p, struct mls_range *r)
179{
180 return (mls_level_isvalid(p, &r->level[0]) &&
181 mls_level_isvalid(p, &r->level[1]) &&
182 mls_level_dom(&r->level[1], &r->level[0]));
183}
184
185/*
186 * Return 1 if the MLS fields in the security context
187 * structure `c' are valid. Return 0 otherwise.
188 */
189int mls_context_isvalid(struct policydb *p, struct context *c)
190{
191 struct user_datum *usrdatum;
192
193 if (!p->mls_enabled)
194 return 1;
195
196 if (!mls_range_isvalid(p, &c->range))
197 return 0;
198
199 if (c->role == OBJECT_R_VAL)
200 return 1;
201
202 /*
203 * User must be authorized for the MLS range.
204 */
205 if (!c->user || c->user > p->p_users.nprim)
206 return 0;
207 usrdatum = p->user_val_to_struct[c->user - 1];
208 if (!mls_range_contains(usrdatum->range, c->range))
209 return 0; /* user may not be associated with range */
210
211 return 1;
212}
213
214/*
215 * Set the MLS fields in the security context structure
216 * `context' based on the string representation in
217 * the string `scontext'.
218 *
219 * This function modifies the string in place, inserting
220 * NULL characters to terminate the MLS fields.
221 *
222 * If a def_sid is provided and no MLS field is present,
223 * copy the MLS field of the associated default context.
224 * Used for upgraded to MLS systems where objects may lack
225 * MLS fields.
226 *
227 * Policy read-lock must be held for sidtab lookup.
228 *
229 */
230int mls_context_to_sid(struct policydb *pol, char oldc, char *scontext,
231 struct context *context, struct sidtab *s, u32 def_sid)
232{
233 char *sensitivity, *cur_cat, *next_cat, *rngptr;
234 struct level_datum *levdatum;
235 struct cat_datum *catdatum, *rngdatum;
236 u32 i;
237 int l, rc;
238 char *rangep[2];
239
240 if (!pol->mls_enabled) {
241 /*
242 * With no MLS, only return -EINVAL if there is a MLS field
243 * and it did not come from an xattr.
244 */
245 if (oldc && def_sid == SECSID_NULL)
246 return -EINVAL;
247 return 0;
248 }
249
250 /*
251 * No MLS component to the security context, try and map to
252 * default if provided.
253 */
254 if (!oldc) {
255 struct context *defcon;
256
257 if (def_sid == SECSID_NULL)
258 return -EINVAL;
259
260 defcon = sidtab_search(s, def_sid);
261 if (!defcon)
262 return -EINVAL;
263
264 return mls_context_cpy(context, defcon);
265 }
266
267 /*
268 * If we're dealing with a range, figure out where the two parts
269 * of the range begin.
270 */
271 rangep[0] = scontext;
272 rangep[1] = strchr(scontext, '-');
273 if (rangep[1]) {
274 rangep[1][0] = '\0';
275 rangep[1]++;
276 }
277
278 /* For each part of the range: */
279 for (l = 0; l < 2; l++) {
280 /* Split sensitivity and category set. */
281 sensitivity = rangep[l];
282 if (sensitivity == NULL)
283 break;
284 next_cat = strchr(sensitivity, ':');
285 if (next_cat)
286 *(next_cat++) = '\0';
287
288 /* Parse sensitivity. */
289 levdatum = symtab_search(&pol->p_levels, sensitivity);
290 if (!levdatum)
291 return -EINVAL;
292 context->range.level[l].sens = levdatum->level->sens;
293
294 /* Extract category set. */
295 while (next_cat != NULL) {
296 cur_cat = next_cat;
297 next_cat = strchr(next_cat, ',');
298 if (next_cat != NULL)
299 *(next_cat++) = '\0';
300
301 /* Separate into range if exists */
302 rngptr = strchr(cur_cat, '.');
303 if (rngptr != NULL) {
304 /* Remove '.' */
305 *rngptr++ = '\0';
306 }
307
308 catdatum = symtab_search(&pol->p_cats, cur_cat);
309 if (!catdatum)
310 return -EINVAL;
311
312 rc = ebitmap_set_bit(&context->range.level[l].cat,
313 catdatum->value - 1, 1);
314 if (rc)
315 return rc;
316
317 /* If range, set all categories in range */
318 if (rngptr == NULL)
319 continue;
320
321 rngdatum = symtab_search(&pol->p_cats, rngptr);
322 if (!rngdatum)
323 return -EINVAL;
324
325 if (catdatum->value >= rngdatum->value)
326 return -EINVAL;
327
328 for (i = catdatum->value; i < rngdatum->value; i++) {
329 rc = ebitmap_set_bit(
330 &context->range.level[l].cat, i, 1);
331 if (rc)
332 return rc;
333 }
334 }
335 }
336
337 /* If we didn't see a '-', the range start is also the range end. */
338 if (rangep[1] == NULL) {
339 context->range.level[1].sens = context->range.level[0].sens;
340 rc = ebitmap_cpy(&context->range.level[1].cat,
341 &context->range.level[0].cat);
342 if (rc)
343 return rc;
344 }
345
346 return 0;
347}
348
349/*
350 * Set the MLS fields in the security context structure
351 * `context' based on the string representation in
352 * the string `str'. This function will allocate temporary memory with the
353 * given constraints of gfp_mask.
354 */
355int mls_from_string(struct policydb *p, char *str, struct context *context,
356 gfp_t gfp_mask)
357{
358 char *tmpstr;
359 int rc;
360
361 if (!p->mls_enabled)
362 return -EINVAL;
363
364 tmpstr = kstrdup(str, gfp_mask);
365 if (!tmpstr) {
366 rc = -ENOMEM;
367 } else {
368 rc = mls_context_to_sid(p, ':', tmpstr, context, NULL,
369 SECSID_NULL);
370 kfree(tmpstr);
371 }
372
373 return rc;
374}
375
376/*
377 * Copies the MLS range `range' into `context'.
378 */
379int mls_range_set(struct context *context, struct mls_range *range)
380{
381 int l, rc = 0;
382
383 /* Copy the MLS range into the context */
384 for (l = 0; l < 2; l++) {
385 context->range.level[l].sens = range->level[l].sens;
386 rc = ebitmap_cpy(&context->range.level[l].cat,
387 &range->level[l].cat);
388 if (rc)
389 break;
390 }
391
392 return rc;
393}
394
395int mls_setup_user_range(struct policydb *p, struct context *fromcon,
396 struct user_datum *user, struct context *usercon)
397{
398 if (p->mls_enabled) {
399 struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
400 struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
401 struct mls_level *user_low = &(user->range.level[0]);
402 struct mls_level *user_clr = &(user->range.level[1]);
403 struct mls_level *user_def = &(user->dfltlevel);
404 struct mls_level *usercon_sen = &(usercon->range.level[0]);
405 struct mls_level *usercon_clr = &(usercon->range.level[1]);
406
407 /* Honor the user's default level if we can */
408 if (mls_level_between(user_def, fromcon_sen, fromcon_clr))
409 *usercon_sen = *user_def;
410 else if (mls_level_between(fromcon_sen, user_def, user_clr))
411 *usercon_sen = *fromcon_sen;
412 else if (mls_level_between(fromcon_clr, user_low, user_def))
413 *usercon_sen = *user_low;
414 else
415 return -EINVAL;
416
417 /* Lower the clearance of available contexts
418 if the clearance of "fromcon" is lower than
419 that of the user's default clearance (but
420 only if the "fromcon" clearance dominates
421 the user's computed sensitivity level) */
422 if (mls_level_dom(user_clr, fromcon_clr))
423 *usercon_clr = *fromcon_clr;
424 else if (mls_level_dom(fromcon_clr, user_clr))
425 *usercon_clr = *user_clr;
426 else
427 return -EINVAL;
428 }
429
430 return 0;
431}
432
433/*
434 * Convert the MLS fields in the security context
435 * structure `oldc' from the values specified in the
436 * policy `oldp' to the values specified in the policy `newp',
437 * storing the resulting context in `newc'.
438 */
439int mls_convert_context(struct policydb *oldp, struct policydb *newp,
440 struct context *oldc, struct context *newc)
441{
442 struct level_datum *levdatum;
443 struct cat_datum *catdatum;
444 struct ebitmap_node *node;
445 u32 i;
446 int l;
447
448 if (!oldp->mls_enabled || !newp->mls_enabled)
449 return 0;
450
451 for (l = 0; l < 2; l++) {
452 char *name = sym_name(oldp, SYM_LEVELS,
453 oldc->range.level[l].sens - 1);
454
455 levdatum = symtab_search(&newp->p_levels, name);
456
457 if (!levdatum)
458 return -EINVAL;
459 newc->range.level[l].sens = levdatum->level->sens;
460
461 ebitmap_for_each_positive_bit(&oldc->range.level[l].cat, node,
462 i)
463 {
464 int rc;
465
466 catdatum = symtab_search(&newp->p_cats,
467 sym_name(oldp, SYM_CATS, i));
468 if (!catdatum)
469 return -EINVAL;
470 rc = ebitmap_set_bit(&newc->range.level[l].cat,
471 catdatum->value - 1, 1);
472 if (rc)
473 return rc;
474 }
475 }
476
477 return 0;
478}
479
480int mls_compute_sid(struct policydb *p, struct context *scontext,
481 struct context *tcontext, u16 tclass, u32 specified,
482 struct context *newcontext, bool sock)
483{
484 struct range_trans rtr;
485 struct mls_range *r;
486 struct class_datum *cladatum;
487 char default_range = 0;
488
489 if (!p->mls_enabled)
490 return 0;
491
492 switch (specified) {
493 case AVTAB_TRANSITION:
494 /* Look for a range transition rule. */
495 rtr.source_type = scontext->type;
496 rtr.target_type = tcontext->type;
497 rtr.target_class = tclass;
498 r = policydb_rangetr_search(p, &rtr);
499 if (r)
500 return mls_range_set(newcontext, r);
501
502 if (tclass && tclass <= p->p_classes.nprim) {
503 cladatum = p->class_val_to_struct[tclass - 1];
504 if (cladatum)
505 default_range = cladatum->default_range;
506 }
507
508 switch (default_range) {
509 case DEFAULT_SOURCE_LOW:
510 return mls_context_cpy_low(newcontext, scontext);
511 case DEFAULT_SOURCE_HIGH:
512 return mls_context_cpy_high(newcontext, scontext);
513 case DEFAULT_SOURCE_LOW_HIGH:
514 return mls_context_cpy(newcontext, scontext);
515 case DEFAULT_TARGET_LOW:
516 return mls_context_cpy_low(newcontext, tcontext);
517 case DEFAULT_TARGET_HIGH:
518 return mls_context_cpy_high(newcontext, tcontext);
519 case DEFAULT_TARGET_LOW_HIGH:
520 return mls_context_cpy(newcontext, tcontext);
521 case DEFAULT_GLBLUB:
522 return mls_context_glblub(newcontext, scontext,
523 tcontext);
524 }
525
526 fallthrough;
527 case AVTAB_CHANGE:
528 if ((tclass == p->process_class) || sock)
529 /* Use the process MLS attributes. */
530 return mls_context_cpy(newcontext, scontext);
531 else
532 /* Use the process effective MLS attributes. */
533 return mls_context_cpy_low(newcontext, scontext);
534 case AVTAB_MEMBER:
535 /* Use the process effective MLS attributes. */
536 return mls_context_cpy_low(newcontext, scontext);
537 }
538 return -EINVAL;
539}
540
541#ifdef CONFIG_NETLABEL
542/**
543 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
544 * @p: the policy
545 * @context: the security context
546 * @secattr: the NetLabel security attributes
547 *
548 * Description:
549 * Given the security context copy the low MLS sensitivity level into the
550 * NetLabel MLS sensitivity level field.
551 *
552 */
553void mls_export_netlbl_lvl(struct policydb *p, struct context *context,
554 struct netlbl_lsm_secattr *secattr)
555{
556 if (!p->mls_enabled)
557 return;
558
559 secattr->attr.mls.lvl = context->range.level[0].sens - 1;
560 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
561}
562
563/**
564 * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
565 * @p: the policy
566 * @context: the security context
567 * @secattr: the NetLabel security attributes
568 *
569 * Description:
570 * Given the security context and the NetLabel security attributes, copy the
571 * NetLabel MLS sensitivity level into the context.
572 *
573 */
574void mls_import_netlbl_lvl(struct policydb *p, struct context *context,
575 struct netlbl_lsm_secattr *secattr)
576{
577 if (!p->mls_enabled)
578 return;
579
580 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
581 context->range.level[1].sens = context->range.level[0].sens;
582}
583
584/**
585 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
586 * @p: the policy
587 * @context: the security context
588 * @secattr: the NetLabel security attributes
589 *
590 * Description:
591 * Given the security context copy the low MLS categories into the NetLabel
592 * MLS category field. Returns zero on success, negative values on failure.
593 *
594 */
595int mls_export_netlbl_cat(struct policydb *p, struct context *context,
596 struct netlbl_lsm_secattr *secattr)
597{
598 int rc;
599
600 if (!p->mls_enabled)
601 return 0;
602
603 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
604 &secattr->attr.mls.cat);
605 if (rc == 0 && secattr->attr.mls.cat != NULL)
606 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
607
608 return rc;
609}
610
611/**
612 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
613 * @p: the policy
614 * @context: the security context
615 * @secattr: the NetLabel security attributes
616 *
617 * Description:
618 * Copy the NetLabel security attributes into the SELinux context; since the
619 * NetLabel security attribute only contains a single MLS category use it for
620 * both the low and high categories of the context. Returns zero on success,
621 * negative values on failure.
622 *
623 */
624int mls_import_netlbl_cat(struct policydb *p, struct context *context,
625 struct netlbl_lsm_secattr *secattr)
626{
627 int rc;
628
629 if (!p->mls_enabled)
630 return 0;
631
632 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
633 secattr->attr.mls.cat);
634 if (rc)
635 goto import_netlbl_cat_failure;
636 memcpy(&context->range.level[1].cat, &context->range.level[0].cat,
637 sizeof(context->range.level[0].cat));
638
639 return 0;
640
641import_netlbl_cat_failure:
642 ebitmap_destroy(&context->range.level[0].cat);
643 return rc;
644}
645#endif /* CONFIG_NETLABEL */