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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 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 = symtab_search(&p->p_levels,
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'.
222 *
223 * This function modifies the string in place, inserting
224 * NULL characters to terminate the MLS fields.
225 *
226 * If a def_sid is provided and no MLS field is present,
227 * copy the MLS field of the associated default context.
228 * Used for upgraded to MLS systems where objects may lack
229 * MLS fields.
230 *
231 * Policy read-lock must be held for sidtab lookup.
232 *
233 */
234int mls_context_to_sid(struct policydb *pol,
235 char oldc,
236 char *scontext,
237 struct context *context,
238 struct sidtab *s,
239 u32 def_sid)
240{
241 char *sensitivity, *cur_cat, *next_cat, *rngptr;
242 struct level_datum *levdatum;
243 struct cat_datum *catdatum, *rngdatum;
244 int l, rc, i;
245 char *rangep[2];
246
247 if (!pol->mls_enabled) {
248 /*
249 * With no MLS, only return -EINVAL if there is a MLS field
250 * and it did not come from an xattr.
251 */
252 if (oldc && def_sid == SECSID_NULL)
253 return -EINVAL;
254 return 0;
255 }
256
257 /*
258 * No MLS component to the security context, try and map to
259 * default if provided.
260 */
261 if (!oldc) {
262 struct context *defcon;
263
264 if (def_sid == SECSID_NULL)
265 return -EINVAL;
266
267 defcon = sidtab_search(s, def_sid);
268 if (!defcon)
269 return -EINVAL;
270
271 return mls_context_cpy(context, defcon);
272 }
273
274 /*
275 * If we're dealing with a range, figure out where the two parts
276 * of the range begin.
277 */
278 rangep[0] = scontext;
279 rangep[1] = strchr(scontext, '-');
280 if (rangep[1]) {
281 rangep[1][0] = '\0';
282 rangep[1]++;
283 }
284
285 /* For each part of the range: */
286 for (l = 0; l < 2; l++) {
287 /* Split sensitivity and category set. */
288 sensitivity = rangep[l];
289 if (sensitivity == NULL)
290 break;
291 next_cat = strchr(sensitivity, ':');
292 if (next_cat)
293 *(next_cat++) = '\0';
294
295 /* Parse sensitivity. */
296 levdatum = symtab_search(&pol->p_levels, sensitivity);
297 if (!levdatum)
298 return -EINVAL;
299 context->range.level[l].sens = levdatum->level->sens;
300
301 /* Extract category set. */
302 while (next_cat != NULL) {
303 cur_cat = next_cat;
304 next_cat = strchr(next_cat, ',');
305 if (next_cat != NULL)
306 *(next_cat++) = '\0';
307
308 /* Separate into range if exists */
309 rngptr = strchr(cur_cat, '.');
310 if (rngptr != NULL) {
311 /* Remove '.' */
312 *rngptr++ = '\0';
313 }
314
315 catdatum = symtab_search(&pol->p_cats, cur_cat);
316 if (!catdatum)
317 return -EINVAL;
318
319 rc = ebitmap_set_bit(&context->range.level[l].cat,
320 catdatum->value - 1, 1);
321 if (rc)
322 return rc;
323
324 /* If range, set all categories in range */
325 if (rngptr == NULL)
326 continue;
327
328 rngdatum = symtab_search(&pol->p_cats, rngptr);
329 if (!rngdatum)
330 return -EINVAL;
331
332 if (catdatum->value >= rngdatum->value)
333 return -EINVAL;
334
335 for (i = catdatum->value; i < rngdatum->value; i++) {
336 rc = ebitmap_set_bit(&context->range.level[l].cat, i, 1);
337 if (rc)
338 return rc;
339 }
340 }
341 }
342
343 /* If we didn't see a '-', the range start is also the range end. */
344 if (rangep[1] == NULL) {
345 context->range.level[1].sens = context->range.level[0].sens;
346 rc = ebitmap_cpy(&context->range.level[1].cat,
347 &context->range.level[0].cat);
348 if (rc)
349 return rc;
350 }
351
352 return 0;
353}
354
355/*
356 * Set the MLS fields in the security context structure
357 * `context' based on the string representation in
358 * the string `str'. This function will allocate temporary memory with the
359 * given constraints of gfp_mask.
360 */
361int mls_from_string(struct policydb *p, char *str, struct context *context,
362 gfp_t gfp_mask)
363{
364 char *tmpstr;
365 int rc;
366
367 if (!p->mls_enabled)
368 return -EINVAL;
369
370 tmpstr = kstrdup(str, gfp_mask);
371 if (!tmpstr) {
372 rc = -ENOMEM;
373 } else {
374 rc = mls_context_to_sid(p, ':', tmpstr, context,
375 NULL, SECSID_NULL);
376 kfree(tmpstr);
377 }
378
379 return rc;
380}
381
382/*
383 * Copies the MLS range `range' into `context'.
384 */
385int mls_range_set(struct context *context,
386 struct mls_range *range)
387{
388 int l, rc = 0;
389
390 /* Copy the MLS range into the context */
391 for (l = 0; l < 2; l++) {
392 context->range.level[l].sens = range->level[l].sens;
393 rc = ebitmap_cpy(&context->range.level[l].cat,
394 &range->level[l].cat);
395 if (rc)
396 break;
397 }
398
399 return rc;
400}
401
402int mls_setup_user_range(struct policydb *p,
403 struct context *fromcon, struct user_datum *user,
404 struct context *usercon)
405{
406 if (p->mls_enabled) {
407 struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
408 struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
409 struct mls_level *user_low = &(user->range.level[0]);
410 struct mls_level *user_clr = &(user->range.level[1]);
411 struct mls_level *user_def = &(user->dfltlevel);
412 struct mls_level *usercon_sen = &(usercon->range.level[0]);
413 struct mls_level *usercon_clr = &(usercon->range.level[1]);
414
415 /* Honor the user's default level if we can */
416 if (mls_level_between(user_def, fromcon_sen, fromcon_clr))
417 *usercon_sen = *user_def;
418 else if (mls_level_between(fromcon_sen, user_def, user_clr))
419 *usercon_sen = *fromcon_sen;
420 else if (mls_level_between(fromcon_clr, user_low, user_def))
421 *usercon_sen = *user_low;
422 else
423 return -EINVAL;
424
425 /* Lower the clearance of available contexts
426 if the clearance of "fromcon" is lower than
427 that of the user's default clearance (but
428 only if the "fromcon" clearance dominates
429 the user's computed sensitivity level) */
430 if (mls_level_dom(user_clr, fromcon_clr))
431 *usercon_clr = *fromcon_clr;
432 else if (mls_level_dom(fromcon_clr, user_clr))
433 *usercon_clr = *user_clr;
434 else
435 return -EINVAL;
436 }
437
438 return 0;
439}
440
441/*
442 * Convert the MLS fields in the security context
443 * structure `oldc' from the values specified in the
444 * policy `oldp' to the values specified in the policy `newp',
445 * storing the resulting context in `newc'.
446 */
447int mls_convert_context(struct policydb *oldp,
448 struct policydb *newp,
449 struct context *oldc,
450 struct context *newc)
451{
452 struct level_datum *levdatum;
453 struct cat_datum *catdatum;
454 struct ebitmap_node *node;
455 int l, i;
456
457 if (!oldp->mls_enabled || !newp->mls_enabled)
458 return 0;
459
460 for (l = 0; l < 2; l++) {
461 char *name = sym_name(oldp, SYM_LEVELS,
462 oldc->range.level[l].sens - 1);
463
464 levdatum = symtab_search(&newp->p_levels, name);
465
466 if (!levdatum)
467 return -EINVAL;
468 newc->range.level[l].sens = levdatum->level->sens;
469
470 ebitmap_for_each_positive_bit(&oldc->range.level[l].cat,
471 node, i) {
472 int rc;
473
474 catdatum = symtab_search(&newp->p_cats,
475 sym_name(oldp, SYM_CATS, i));
476 if (!catdatum)
477 return -EINVAL;
478 rc = ebitmap_set_bit(&newc->range.level[l].cat,
479 catdatum->value - 1, 1);
480 if (rc)
481 return rc;
482 }
483 }
484
485 return 0;
486}
487
488int mls_compute_sid(struct policydb *p,
489 struct context *scontext,
490 struct context *tcontext,
491 u16 tclass,
492 u32 specified,
493 struct context *newcontext,
494 bool sock)
495{
496 struct range_trans rtr;
497 struct mls_range *r;
498 struct class_datum *cladatum;
499 int default_range = 0;
500
501 if (!p->mls_enabled)
502 return 0;
503
504 switch (specified) {
505 case AVTAB_TRANSITION:
506 /* Look for a range transition rule. */
507 rtr.source_type = scontext->type;
508 rtr.target_type = tcontext->type;
509 rtr.target_class = tclass;
510 r = policydb_rangetr_search(p, &rtr);
511 if (r)
512 return mls_range_set(newcontext, r);
513
514 if (tclass && tclass <= p->p_classes.nprim) {
515 cladatum = p->class_val_to_struct[tclass - 1];
516 if (cladatum)
517 default_range = cladatum->default_range;
518 }
519
520 switch (default_range) {
521 case DEFAULT_SOURCE_LOW:
522 return mls_context_cpy_low(newcontext, scontext);
523 case DEFAULT_SOURCE_HIGH:
524 return mls_context_cpy_high(newcontext, scontext);
525 case DEFAULT_SOURCE_LOW_HIGH:
526 return mls_context_cpy(newcontext, scontext);
527 case DEFAULT_TARGET_LOW:
528 return mls_context_cpy_low(newcontext, tcontext);
529 case DEFAULT_TARGET_HIGH:
530 return mls_context_cpy_high(newcontext, tcontext);
531 case DEFAULT_TARGET_LOW_HIGH:
532 return mls_context_cpy(newcontext, tcontext);
533 case DEFAULT_GLBLUB:
534 return mls_context_glblub(newcontext,
535 scontext, tcontext);
536 }
537
538 fallthrough;
539 case AVTAB_CHANGE:
540 if ((tclass == p->process_class) || sock)
541 /* Use the process MLS attributes. */
542 return mls_context_cpy(newcontext, scontext);
543 else
544 /* Use the process effective MLS attributes. */
545 return mls_context_cpy_low(newcontext, scontext);
546 case AVTAB_MEMBER:
547 /* Use the process effective MLS attributes. */
548 return mls_context_cpy_low(newcontext, scontext);
549 }
550 return -EINVAL;
551}
552
553#ifdef CONFIG_NETLABEL
554/**
555 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
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 * @context: the security context
578 * @secattr: the NetLabel security attributes
579 *
580 * Description:
581 * Given the security context and the NetLabel security attributes, copy the
582 * NetLabel MLS sensitivity level into the context.
583 *
584 */
585void mls_import_netlbl_lvl(struct policydb *p,
586 struct context *context,
587 struct netlbl_lsm_secattr *secattr)
588{
589 if (!p->mls_enabled)
590 return;
591
592 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
593 context->range.level[1].sens = context->range.level[0].sens;
594}
595
596/**
597 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
598 * @context: the security context
599 * @secattr: the NetLabel security attributes
600 *
601 * Description:
602 * Given the security context copy the low MLS categories into the NetLabel
603 * MLS category field. Returns zero on success, negative values on failure.
604 *
605 */
606int mls_export_netlbl_cat(struct policydb *p,
607 struct context *context,
608 struct netlbl_lsm_secattr *secattr)
609{
610 int rc;
611
612 if (!p->mls_enabled)
613 return 0;
614
615 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
616 &secattr->attr.mls.cat);
617 if (rc == 0 && secattr->attr.mls.cat != NULL)
618 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
619
620 return rc;
621}
622
623/**
624 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
625 * @context: the security context
626 * @secattr: the NetLabel security attributes
627 *
628 * Description:
629 * Copy the NetLabel security attributes into the SELinux context; since the
630 * NetLabel security attribute only contains a single MLS category use it for
631 * both the low and high categories of the context. Returns zero on success,
632 * negative values on failure.
633 *
634 */
635int mls_import_netlbl_cat(struct policydb *p,
636 struct context *context,
637 struct netlbl_lsm_secattr *secattr)
638{
639 int rc;
640
641 if (!p->mls_enabled)
642 return 0;
643
644 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
645 secattr->attr.mls.cat);
646 if (rc)
647 goto import_netlbl_cat_failure;
648 memcpy(&context->range.level[1].cat, &context->range.level[0].cat,
649 sizeof(context->range.level[0].cat));
650
651 return 0;
652
653import_netlbl_cat_failure:
654 ebitmap_destroy(&context->range.level[0].cat);
655 return rc;
656}
657#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 */