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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 = 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 */
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 */