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