Loading...
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, <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 return;
160}
161
162int mls_level_isvalid(struct policydb *p, struct mls_level *l)
163{
164 struct level_datum *levdatum;
165
166 if (!l->sens || l->sens > p->p_levels.nprim)
167 return 0;
168 levdatum = hashtab_search(p->p_levels.table,
169 sym_name(p, SYM_LEVELS, l->sens - 1));
170 if (!levdatum)
171 return 0;
172
173 /*
174 * Return 1 iff all the bits set in l->cat are also be set in
175 * levdatum->level->cat and no bit in l->cat is larger than
176 * p->p_cats.nprim.
177 */
178 return ebitmap_contains(&levdatum->level->cat, &l->cat,
179 p->p_cats.nprim);
180}
181
182int mls_range_isvalid(struct policydb *p, struct mls_range *r)
183{
184 return (mls_level_isvalid(p, &r->level[0]) &&
185 mls_level_isvalid(p, &r->level[1]) &&
186 mls_level_dom(&r->level[1], &r->level[0]));
187}
188
189/*
190 * Return 1 if the MLS fields in the security context
191 * structure `c' are valid. Return 0 otherwise.
192 */
193int mls_context_isvalid(struct policydb *p, struct context *c)
194{
195 struct user_datum *usrdatum;
196
197 if (!p->mls_enabled)
198 return 1;
199
200 if (!mls_range_isvalid(p, &c->range))
201 return 0;
202
203 if (c->role == OBJECT_R_VAL)
204 return 1;
205
206 /*
207 * User must be authorized for the MLS range.
208 */
209 if (!c->user || c->user > p->p_users.nprim)
210 return 0;
211 usrdatum = p->user_val_to_struct[c->user - 1];
212 if (!mls_range_contains(usrdatum->range, c->range))
213 return 0; /* user may not be associated with range */
214
215 return 1;
216}
217
218/*
219 * Set the MLS fields in the security context structure
220 * `context' based on the string representation in
221 * the string `*scontext'. Update `*scontext' to
222 * point to the end of the string representation of
223 * the MLS fields.
224 *
225 * This function modifies the string in place, inserting
226 * NULL characters to terminate the MLS fields.
227 *
228 * If a def_sid is provided and no MLS field is present,
229 * copy the MLS field of the associated default context.
230 * Used for upgraded to MLS systems where objects may lack
231 * MLS fields.
232 *
233 * Policy read-lock must be held for sidtab lookup.
234 *
235 */
236int mls_context_to_sid(struct policydb *pol,
237 char oldc,
238 char **scontext,
239 struct context *context,
240 struct sidtab *s,
241 u32 def_sid)
242{
243
244 char delim;
245 char *scontextp, *p, *rngptr;
246 struct level_datum *levdatum;
247 struct cat_datum *catdatum, *rngdatum;
248 int l, rc = -EINVAL;
249
250 if (!pol->mls_enabled) {
251 if (def_sid != SECSID_NULL && oldc)
252 *scontext += strlen(*scontext) + 1;
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 goto out;
265
266 defcon = sidtab_search(s, def_sid);
267 if (!defcon)
268 goto out;
269
270 rc = mls_context_cpy(context, defcon);
271 goto out;
272 }
273
274 /* Extract low sensitivity. */
275 scontextp = p = *scontext;
276 while (*p && *p != ':' && *p != '-')
277 p++;
278
279 delim = *p;
280 if (delim != '\0')
281 *p++ = '\0';
282
283 for (l = 0; l < 2; l++) {
284 levdatum = hashtab_search(pol->p_levels.table, scontextp);
285 if (!levdatum) {
286 rc = -EINVAL;
287 goto out;
288 }
289
290 context->range.level[l].sens = levdatum->level->sens;
291
292 if (delim == ':') {
293 /* Extract category set. */
294 while (1) {
295 scontextp = p;
296 while (*p && *p != ',' && *p != '-')
297 p++;
298 delim = *p;
299 if (delim != '\0')
300 *p++ = '\0';
301
302 /* Separate into range if exists */
303 rngptr = strchr(scontextp, '.');
304 if (rngptr != NULL) {
305 /* Remove '.' */
306 *rngptr++ = '\0';
307 }
308
309 catdatum = hashtab_search(pol->p_cats.table,
310 scontextp);
311 if (!catdatum) {
312 rc = -EINVAL;
313 goto out;
314 }
315
316 rc = ebitmap_set_bit(&context->range.level[l].cat,
317 catdatum->value - 1, 1);
318 if (rc)
319 goto out;
320
321 /* If range, set all categories in range */
322 if (rngptr) {
323 int i;
324
325 rngdatum = hashtab_search(pol->p_cats.table, rngptr);
326 if (!rngdatum) {
327 rc = -EINVAL;
328 goto out;
329 }
330
331 if (catdatum->value >= rngdatum->value) {
332 rc = -EINVAL;
333 goto out;
334 }
335
336 for (i = catdatum->value; i < rngdatum->value; i++) {
337 rc = ebitmap_set_bit(&context->range.level[l].cat, i, 1);
338 if (rc)
339 goto out;
340 }
341 }
342
343 if (delim != ',')
344 break;
345 }
346 }
347 if (delim == '-') {
348 /* Extract high sensitivity. */
349 scontextp = p;
350 while (*p && *p != ':')
351 p++;
352
353 delim = *p;
354 if (delim != '\0')
355 *p++ = '\0';
356 } else
357 break;
358 }
359
360 if (l == 0) {
361 context->range.level[1].sens = context->range.level[0].sens;
362 rc = ebitmap_cpy(&context->range.level[1].cat,
363 &context->range.level[0].cat);
364 if (rc)
365 goto out;
366 }
367 *scontext = ++p;
368 rc = 0;
369out:
370 return rc;
371}
372
373/*
374 * Set the MLS fields in the security context structure
375 * `context' based on the string representation in
376 * the string `str'. This function will allocate temporary memory with the
377 * given constraints of gfp_mask.
378 */
379int mls_from_string(struct policydb *p, char *str, struct context *context,
380 gfp_t gfp_mask)
381{
382 char *tmpstr, *freestr;
383 int rc;
384
385 if (!p->mls_enabled)
386 return -EINVAL;
387
388 /* we need freestr because mls_context_to_sid will change
389 the value of tmpstr */
390 tmpstr = freestr = kstrdup(str, gfp_mask);
391 if (!tmpstr) {
392 rc = -ENOMEM;
393 } else {
394 rc = mls_context_to_sid(p, ':', &tmpstr, context,
395 NULL, SECSID_NULL);
396 kfree(freestr);
397 }
398
399 return rc;
400}
401
402/*
403 * Copies the MLS range `range' into `context'.
404 */
405int mls_range_set(struct context *context,
406 struct mls_range *range)
407{
408 int l, rc = 0;
409
410 /* Copy the MLS range into the context */
411 for (l = 0; l < 2; l++) {
412 context->range.level[l].sens = range->level[l].sens;
413 rc = ebitmap_cpy(&context->range.level[l].cat,
414 &range->level[l].cat);
415 if (rc)
416 break;
417 }
418
419 return rc;
420}
421
422int mls_setup_user_range(struct policydb *p,
423 struct context *fromcon, struct user_datum *user,
424 struct context *usercon)
425{
426 if (p->mls_enabled) {
427 struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
428 struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
429 struct mls_level *user_low = &(user->range.level[0]);
430 struct mls_level *user_clr = &(user->range.level[1]);
431 struct mls_level *user_def = &(user->dfltlevel);
432 struct mls_level *usercon_sen = &(usercon->range.level[0]);
433 struct mls_level *usercon_clr = &(usercon->range.level[1]);
434
435 /* Honor the user's default level if we can */
436 if (mls_level_between(user_def, fromcon_sen, fromcon_clr))
437 *usercon_sen = *user_def;
438 else if (mls_level_between(fromcon_sen, user_def, user_clr))
439 *usercon_sen = *fromcon_sen;
440 else if (mls_level_between(fromcon_clr, user_low, user_def))
441 *usercon_sen = *user_low;
442 else
443 return -EINVAL;
444
445 /* Lower the clearance of available contexts
446 if the clearance of "fromcon" is lower than
447 that of the user's default clearance (but
448 only if the "fromcon" clearance dominates
449 the user's computed sensitivity level) */
450 if (mls_level_dom(user_clr, fromcon_clr))
451 *usercon_clr = *fromcon_clr;
452 else if (mls_level_dom(fromcon_clr, user_clr))
453 *usercon_clr = *user_clr;
454 else
455 return -EINVAL;
456 }
457
458 return 0;
459}
460
461/*
462 * Convert the MLS fields in the security context
463 * structure `c' from the values specified in the
464 * policy `oldp' to the values specified in the policy `newp'.
465 */
466int mls_convert_context(struct policydb *oldp,
467 struct policydb *newp,
468 struct context *c)
469{
470 struct level_datum *levdatum;
471 struct cat_datum *catdatum;
472 struct ebitmap bitmap;
473 struct ebitmap_node *node;
474 int l, i;
475
476 if (!oldp->mls_enabled || !newp->mls_enabled)
477 return 0;
478
479 for (l = 0; l < 2; l++) {
480 levdatum = hashtab_search(newp->p_levels.table,
481 sym_name(oldp, SYM_LEVELS,
482 c->range.level[l].sens - 1));
483
484 if (!levdatum)
485 return -EINVAL;
486 c->range.level[l].sens = levdatum->level->sens;
487
488 ebitmap_init(&bitmap);
489 ebitmap_for_each_positive_bit(&c->range.level[l].cat, node, i) {
490 int rc;
491
492 catdatum = hashtab_search(newp->p_cats.table,
493 sym_name(oldp, SYM_CATS, i));
494 if (!catdatum)
495 return -EINVAL;
496 rc = ebitmap_set_bit(&bitmap, catdatum->value - 1, 1);
497 if (rc)
498 return rc;
499
500 cond_resched();
501 }
502 ebitmap_destroy(&c->range.level[l].cat);
503 c->range.level[l].cat = bitmap;
504 }
505
506 return 0;
507}
508
509int mls_compute_sid(struct policydb *p,
510 struct context *scontext,
511 struct context *tcontext,
512 u16 tclass,
513 u32 specified,
514 struct context *newcontext,
515 bool sock)
516{
517 struct range_trans rtr;
518 struct mls_range *r;
519 struct class_datum *cladatum;
520 int default_range = 0;
521
522 if (!p->mls_enabled)
523 return 0;
524
525 switch (specified) {
526 case AVTAB_TRANSITION:
527 /* Look for a range transition rule. */
528 rtr.source_type = scontext->type;
529 rtr.target_type = tcontext->type;
530 rtr.target_class = tclass;
531 r = hashtab_search(p->range_tr, &rtr);
532 if (r)
533 return mls_range_set(newcontext, r);
534
535 if (tclass && tclass <= p->p_classes.nprim) {
536 cladatum = p->class_val_to_struct[tclass - 1];
537 if (cladatum)
538 default_range = cladatum->default_range;
539 }
540
541 switch (default_range) {
542 case DEFAULT_SOURCE_LOW:
543 return mls_context_cpy_low(newcontext, scontext);
544 case DEFAULT_SOURCE_HIGH:
545 return mls_context_cpy_high(newcontext, scontext);
546 case DEFAULT_SOURCE_LOW_HIGH:
547 return mls_context_cpy(newcontext, scontext);
548 case DEFAULT_TARGET_LOW:
549 return mls_context_cpy_low(newcontext, tcontext);
550 case DEFAULT_TARGET_HIGH:
551 return mls_context_cpy_high(newcontext, tcontext);
552 case DEFAULT_TARGET_LOW_HIGH:
553 return mls_context_cpy(newcontext, tcontext);
554 }
555
556 /* Fallthrough */
557 case AVTAB_CHANGE:
558 if ((tclass == p->process_class) || (sock == true))
559 /* Use the process MLS attributes. */
560 return mls_context_cpy(newcontext, scontext);
561 else
562 /* Use the process effective MLS attributes. */
563 return mls_context_cpy_low(newcontext, scontext);
564 case AVTAB_MEMBER:
565 /* Use the process effective MLS attributes. */
566 return mls_context_cpy_low(newcontext, scontext);
567
568 /* fall through */
569 }
570 return -EINVAL;
571}
572
573#ifdef CONFIG_NETLABEL
574/**
575 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
576 * @context: the security context
577 * @secattr: the NetLabel security attributes
578 *
579 * Description:
580 * Given the security context copy the low MLS sensitivity level into the
581 * NetLabel MLS sensitivity level field.
582 *
583 */
584void mls_export_netlbl_lvl(struct policydb *p,
585 struct context *context,
586 struct netlbl_lsm_secattr *secattr)
587{
588 if (!p->mls_enabled)
589 return;
590
591 secattr->attr.mls.lvl = context->range.level[0].sens - 1;
592 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
593}
594
595/**
596 * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
597 * @context: the security context
598 * @secattr: the NetLabel security attributes
599 *
600 * Description:
601 * Given the security context and the NetLabel security attributes, copy the
602 * NetLabel MLS sensitivity level into the context.
603 *
604 */
605void mls_import_netlbl_lvl(struct policydb *p,
606 struct context *context,
607 struct netlbl_lsm_secattr *secattr)
608{
609 if (!p->mls_enabled)
610 return;
611
612 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
613 context->range.level[1].sens = context->range.level[0].sens;
614}
615
616/**
617 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
618 * @context: the security context
619 * @secattr: the NetLabel security attributes
620 *
621 * Description:
622 * Given the security context copy the low MLS categories into the NetLabel
623 * MLS category field. Returns zero on success, negative values on failure.
624 *
625 */
626int mls_export_netlbl_cat(struct policydb *p,
627 struct context *context,
628 struct netlbl_lsm_secattr *secattr)
629{
630 int rc;
631
632 if (!p->mls_enabled)
633 return 0;
634
635 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
636 &secattr->attr.mls.cat);
637 if (rc == 0 && secattr->attr.mls.cat != NULL)
638 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
639
640 return rc;
641}
642
643/**
644 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
645 * @context: the security context
646 * @secattr: the NetLabel security attributes
647 *
648 * Description:
649 * Copy the NetLabel security attributes into the SELinux context; since the
650 * NetLabel security attribute only contains a single MLS category use it for
651 * both the low and high categories of the context. Returns zero on success,
652 * negative values on failure.
653 *
654 */
655int mls_import_netlbl_cat(struct policydb *p,
656 struct context *context,
657 struct netlbl_lsm_secattr *secattr)
658{
659 int rc;
660
661 if (!p->mls_enabled)
662 return 0;
663
664 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
665 secattr->attr.mls.cat);
666 if (rc)
667 goto import_netlbl_cat_failure;
668 memcpy(&context->range.level[1].cat, &context->range.level[0].cat,
669 sizeof(context->range.level[0].cat));
670
671 return 0;
672
673import_netlbl_cat_failure:
674 ebitmap_destroy(&context->range.level[0].cat);
675 return rc;
676}
677#endif /* CONFIG_NETLABEL */