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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 * 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 u32 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 u32 i;
244 int l, rc;
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 u32 i;
456 int l;
457
458 if (!oldp->mls_enabled || !newp->mls_enabled)
459 return 0;
460
461 for (l = 0; l < 2; l++) {
462 char *name = sym_name(oldp, SYM_LEVELS,
463 oldc->range.level[l].sens - 1);
464
465 levdatum = symtab_search(&newp->p_levels, name);
466
467 if (!levdatum)
468 return -EINVAL;
469 newc->range.level[l].sens = levdatum->level->sens;
470
471 ebitmap_for_each_positive_bit(&oldc->range.level[l].cat,
472 node, i) {
473 int rc;
474
475 catdatum = symtab_search(&newp->p_cats,
476 sym_name(oldp, SYM_CATS, i));
477 if (!catdatum)
478 return -EINVAL;
479 rc = ebitmap_set_bit(&newc->range.level[l].cat,
480 catdatum->value - 1, 1);
481 if (rc)
482 return rc;
483 }
484 }
485
486 return 0;
487}
488
489int mls_compute_sid(struct policydb *p,
490 struct context *scontext,
491 struct context *tcontext,
492 u16 tclass,
493 u32 specified,
494 struct context *newcontext,
495 bool sock)
496{
497 struct range_trans rtr;
498 struct mls_range *r;
499 struct class_datum *cladatum;
500 char default_range = 0;
501
502 if (!p->mls_enabled)
503 return 0;
504
505 switch (specified) {
506 case AVTAB_TRANSITION:
507 /* Look for a range transition rule. */
508 rtr.source_type = scontext->type;
509 rtr.target_type = tcontext->type;
510 rtr.target_class = tclass;
511 r = policydb_rangetr_search(p, &rtr);
512 if (r)
513 return mls_range_set(newcontext, r);
514
515 if (tclass && tclass <= p->p_classes.nprim) {
516 cladatum = p->class_val_to_struct[tclass - 1];
517 if (cladatum)
518 default_range = cladatum->default_range;
519 }
520
521 switch (default_range) {
522 case DEFAULT_SOURCE_LOW:
523 return mls_context_cpy_low(newcontext, scontext);
524 case DEFAULT_SOURCE_HIGH:
525 return mls_context_cpy_high(newcontext, scontext);
526 case DEFAULT_SOURCE_LOW_HIGH:
527 return mls_context_cpy(newcontext, scontext);
528 case DEFAULT_TARGET_LOW:
529 return mls_context_cpy_low(newcontext, tcontext);
530 case DEFAULT_TARGET_HIGH:
531 return mls_context_cpy_high(newcontext, tcontext);
532 case DEFAULT_TARGET_LOW_HIGH:
533 return mls_context_cpy(newcontext, tcontext);
534 case DEFAULT_GLBLUB:
535 return mls_context_glblub(newcontext,
536 scontext, tcontext);
537 }
538
539 fallthrough;
540 case AVTAB_CHANGE:
541 if ((tclass == p->process_class) || sock)
542 /* Use the process MLS attributes. */
543 return mls_context_cpy(newcontext, scontext);
544 else
545 /* Use the process effective MLS attributes. */
546 return mls_context_cpy_low(newcontext, scontext);
547 case AVTAB_MEMBER:
548 /* Use the process effective MLS attributes. */
549 return mls_context_cpy_low(newcontext, scontext);
550 }
551 return -EINVAL;
552}
553
554#ifdef CONFIG_NETLABEL
555/**
556 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
557 * @p: the policy
558 * @context: the security context
559 * @secattr: the NetLabel security attributes
560 *
561 * Description:
562 * Given the security context copy the low MLS sensitivity level into the
563 * NetLabel MLS sensitivity level field.
564 *
565 */
566void mls_export_netlbl_lvl(struct policydb *p,
567 struct context *context,
568 struct netlbl_lsm_secattr *secattr)
569{
570 if (!p->mls_enabled)
571 return;
572
573 secattr->attr.mls.lvl = context->range.level[0].sens - 1;
574 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
575}
576
577/**
578 * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
579 * @p: the policy
580 * @context: the security context
581 * @secattr: the NetLabel security attributes
582 *
583 * Description:
584 * Given the security context and the NetLabel security attributes, copy the
585 * NetLabel MLS sensitivity level into the context.
586 *
587 */
588void mls_import_netlbl_lvl(struct policydb *p,
589 struct context *context,
590 struct netlbl_lsm_secattr *secattr)
591{
592 if (!p->mls_enabled)
593 return;
594
595 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
596 context->range.level[1].sens = context->range.level[0].sens;
597}
598
599/**
600 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
601 * @p: the policy
602 * @context: the security context
603 * @secattr: the NetLabel security attributes
604 *
605 * Description:
606 * Given the security context copy the low MLS categories into the NetLabel
607 * MLS category field. Returns zero on success, negative values on failure.
608 *
609 */
610int mls_export_netlbl_cat(struct policydb *p,
611 struct context *context,
612 struct netlbl_lsm_secattr *secattr)
613{
614 int rc;
615
616 if (!p->mls_enabled)
617 return 0;
618
619 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
620 &secattr->attr.mls.cat);
621 if (rc == 0 && secattr->attr.mls.cat != NULL)
622 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
623
624 return rc;
625}
626
627/**
628 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
629 * @p: the policy
630 * @context: the security context
631 * @secattr: the NetLabel security attributes
632 *
633 * Description:
634 * Copy the NetLabel security attributes into the SELinux context; since the
635 * NetLabel security attribute only contains a single MLS category use it for
636 * both the low and high categories of the context. Returns zero on success,
637 * negative values on failure.
638 *
639 */
640int mls_import_netlbl_cat(struct policydb *p,
641 struct context *context,
642 struct netlbl_lsm_secattr *secattr)
643{
644 int rc;
645
646 if (!p->mls_enabled)
647 return 0;
648
649 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
650 secattr->attr.mls.cat);
651 if (rc)
652 goto import_netlbl_cat_failure;
653 memcpy(&context->range.level[1].cat, &context->range.level[0].cat,
654 sizeof(context->range.level[0].cat));
655
656 return 0;
657
658import_netlbl_cat_failure:
659 ebitmap_destroy(&context->range.level[0].cat);
660 return rc;
661}
662#endif /* CONFIG_NETLABEL */