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1/*
2 * Implementation of the multi-level security (MLS) policy.
3 *
4 * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
5 */
6/*
7 * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
8 *
9 * Support for enhanced MLS infrastructure.
10 *
11 * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
12 */
13/*
14 * Updated: Hewlett-Packard <paul@paul-moore.com>
15 *
16 * Added support to import/export the MLS label from NetLabel
17 *
18 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
19 */
20
21#include <linux/kernel.h>
22#include <linux/slab.h>
23#include <linux/string.h>
24#include <linux/errno.h>
25#include <net/netlabel.h>
26#include "sidtab.h"
27#include "mls.h"
28#include "policydb.h"
29#include "services.h"
30
31/*
32 * Return the length in bytes for the MLS fields of the
33 * security context string representation of `context'.
34 */
35int mls_compute_context_len(struct context *context)
36{
37 int i, l, len, head, prev;
38 char *nm;
39 struct ebitmap *e;
40 struct ebitmap_node *node;
41
42 if (!policydb.mls_enabled)
43 return 0;
44
45 len = 1; /* for the beginning ":" */
46 for (l = 0; l < 2; l++) {
47 int index_sens = context->range.level[l].sens;
48 len += strlen(sym_name(&policydb, SYM_LEVELS, index_sens - 1));
49
50 /* categories */
51 head = -2;
52 prev = -2;
53 e = &context->range.level[l].cat;
54 ebitmap_for_each_positive_bit(e, node, i) {
55 if (i - prev > 1) {
56 /* one or more negative bits are skipped */
57 if (head != prev) {
58 nm = sym_name(&policydb, SYM_CATS, prev);
59 len += strlen(nm) + 1;
60 }
61 nm = sym_name(&policydb, SYM_CATS, i);
62 len += strlen(nm) + 1;
63 head = i;
64 }
65 prev = i;
66 }
67 if (prev != head) {
68 nm = sym_name(&policydb, SYM_CATS, prev);
69 len += strlen(nm) + 1;
70 }
71 if (l == 0) {
72 if (mls_level_eq(&context->range.level[0],
73 &context->range.level[1]))
74 break;
75 else
76 len++;
77 }
78 }
79
80 return len;
81}
82
83/*
84 * Write the security context string representation of
85 * the MLS fields of `context' into the string `*scontext'.
86 * Update `*scontext' to point to the end of the MLS fields.
87 */
88void mls_sid_to_context(struct context *context,
89 char **scontext)
90{
91 char *scontextp, *nm;
92 int i, l, head, prev;
93 struct ebitmap *e;
94 struct ebitmap_node *node;
95
96 if (!policydb.mls_enabled)
97 return;
98
99 scontextp = *scontext;
100
101 *scontextp = ':';
102 scontextp++;
103
104 for (l = 0; l < 2; l++) {
105 strcpy(scontextp, sym_name(&policydb, SYM_LEVELS,
106 context->range.level[l].sens - 1));
107 scontextp += strlen(scontextp);
108
109 /* categories */
110 head = -2;
111 prev = -2;
112 e = &context->range.level[l].cat;
113 ebitmap_for_each_positive_bit(e, node, i) {
114 if (i - prev > 1) {
115 /* one or more negative bits are skipped */
116 if (prev != head) {
117 if (prev - head > 1)
118 *scontextp++ = '.';
119 else
120 *scontextp++ = ',';
121 nm = sym_name(&policydb, SYM_CATS, prev);
122 strcpy(scontextp, nm);
123 scontextp += strlen(nm);
124 }
125 if (prev < 0)
126 *scontextp++ = ':';
127 else
128 *scontextp++ = ',';
129 nm = sym_name(&policydb, SYM_CATS, i);
130 strcpy(scontextp, nm);
131 scontextp += strlen(nm);
132 head = i;
133 }
134 prev = i;
135 }
136
137 if (prev != head) {
138 if (prev - head > 1)
139 *scontextp++ = '.';
140 else
141 *scontextp++ = ',';
142 nm = sym_name(&policydb, SYM_CATS, prev);
143 strcpy(scontextp, nm);
144 scontextp += strlen(nm);
145 }
146
147 if (l == 0) {
148 if (mls_level_eq(&context->range.level[0],
149 &context->range.level[1]))
150 break;
151 else
152 *scontextp++ = '-';
153 }
154 }
155
156 *scontext = scontextp;
157 return;
158}
159
160int mls_level_isvalid(struct policydb *p, struct mls_level *l)
161{
162 struct level_datum *levdatum;
163
164 if (!l->sens || l->sens > p->p_levels.nprim)
165 return 0;
166 levdatum = hashtab_search(p->p_levels.table,
167 sym_name(p, SYM_LEVELS, l->sens - 1));
168 if (!levdatum)
169 return 0;
170
171 /*
172 * Return 1 iff all the bits set in l->cat are also be set in
173 * levdatum->level->cat and no bit in l->cat is larger than
174 * p->p_cats.nprim.
175 */
176 return ebitmap_contains(&levdatum->level->cat, &l->cat,
177 p->p_cats.nprim);
178}
179
180int mls_range_isvalid(struct policydb *p, struct mls_range *r)
181{
182 return (mls_level_isvalid(p, &r->level[0]) &&
183 mls_level_isvalid(p, &r->level[1]) &&
184 mls_level_dom(&r->level[1], &r->level[0]));
185}
186
187/*
188 * Return 1 if the MLS fields in the security context
189 * structure `c' are valid. Return 0 otherwise.
190 */
191int mls_context_isvalid(struct policydb *p, struct context *c)
192{
193 struct user_datum *usrdatum;
194
195 if (!p->mls_enabled)
196 return 1;
197
198 if (!mls_range_isvalid(p, &c->range))
199 return 0;
200
201 if (c->role == OBJECT_R_VAL)
202 return 1;
203
204 /*
205 * User must be authorized for the MLS range.
206 */
207 if (!c->user || c->user > p->p_users.nprim)
208 return 0;
209 usrdatum = p->user_val_to_struct[c->user - 1];
210 if (!mls_range_contains(usrdatum->range, c->range))
211 return 0; /* user may not be associated with range */
212
213 return 1;
214}
215
216/*
217 * Set the MLS fields in the security context structure
218 * `context' based on the string representation in
219 * the string `*scontext'. Update `*scontext' to
220 * point to the end of the string representation of
221 * the MLS fields.
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
242 char delim;
243 char *scontextp, *p, *rngptr;
244 struct level_datum *levdatum;
245 struct cat_datum *catdatum, *rngdatum;
246 int l, rc = -EINVAL;
247
248 if (!pol->mls_enabled) {
249 if (def_sid != SECSID_NULL && oldc)
250 *scontext += strlen(*scontext) + 1;
251 return 0;
252 }
253
254 /*
255 * No MLS component to the security context, try and map to
256 * default if provided.
257 */
258 if (!oldc) {
259 struct context *defcon;
260
261 if (def_sid == SECSID_NULL)
262 goto out;
263
264 defcon = sidtab_search(s, def_sid);
265 if (!defcon)
266 goto out;
267
268 rc = mls_context_cpy(context, defcon);
269 goto out;
270 }
271
272 /* Extract low sensitivity. */
273 scontextp = p = *scontext;
274 while (*p && *p != ':' && *p != '-')
275 p++;
276
277 delim = *p;
278 if (delim != '\0')
279 *p++ = '\0';
280
281 for (l = 0; l < 2; l++) {
282 levdatum = hashtab_search(pol->p_levels.table, scontextp);
283 if (!levdatum) {
284 rc = -EINVAL;
285 goto out;
286 }
287
288 context->range.level[l].sens = levdatum->level->sens;
289
290 if (delim == ':') {
291 /* Extract category set. */
292 while (1) {
293 scontextp = p;
294 while (*p && *p != ',' && *p != '-')
295 p++;
296 delim = *p;
297 if (delim != '\0')
298 *p++ = '\0';
299
300 /* Separate into range if exists */
301 rngptr = strchr(scontextp, '.');
302 if (rngptr != NULL) {
303 /* Remove '.' */
304 *rngptr++ = '\0';
305 }
306
307 catdatum = hashtab_search(pol->p_cats.table,
308 scontextp);
309 if (!catdatum) {
310 rc = -EINVAL;
311 goto out;
312 }
313
314 rc = ebitmap_set_bit(&context->range.level[l].cat,
315 catdatum->value - 1, 1);
316 if (rc)
317 goto out;
318
319 /* If range, set all categories in range */
320 if (rngptr) {
321 int i;
322
323 rngdatum = hashtab_search(pol->p_cats.table, rngptr);
324 if (!rngdatum) {
325 rc = -EINVAL;
326 goto out;
327 }
328
329 if (catdatum->value >= rngdatum->value) {
330 rc = -EINVAL;
331 goto out;
332 }
333
334 for (i = catdatum->value; i < rngdatum->value; i++) {
335 rc = ebitmap_set_bit(&context->range.level[l].cat, i, 1);
336 if (rc)
337 goto out;
338 }
339 }
340
341 if (delim != ',')
342 break;
343 }
344 }
345 if (delim == '-') {
346 /* Extract high sensitivity. */
347 scontextp = p;
348 while (*p && *p != ':')
349 p++;
350
351 delim = *p;
352 if (delim != '\0')
353 *p++ = '\0';
354 } else
355 break;
356 }
357
358 if (l == 0) {
359 context->range.level[1].sens = context->range.level[0].sens;
360 rc = ebitmap_cpy(&context->range.level[1].cat,
361 &context->range.level[0].cat);
362 if (rc)
363 goto out;
364 }
365 *scontext = ++p;
366 rc = 0;
367out:
368 return rc;
369}
370
371/*
372 * Set the MLS fields in the security context structure
373 * `context' based on the string representation in
374 * the string `str'. This function will allocate temporary memory with the
375 * given constraints of gfp_mask.
376 */
377int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
378{
379 char *tmpstr, *freestr;
380 int rc;
381
382 if (!policydb.mls_enabled)
383 return -EINVAL;
384
385 /* we need freestr because mls_context_to_sid will change
386 the value of tmpstr */
387 tmpstr = freestr = kstrdup(str, gfp_mask);
388 if (!tmpstr) {
389 rc = -ENOMEM;
390 } else {
391 rc = mls_context_to_sid(&policydb, ':', &tmpstr, context,
392 NULL, SECSID_NULL);
393 kfree(freestr);
394 }
395
396 return rc;
397}
398
399/*
400 * Copies the MLS range `range' into `context'.
401 */
402int mls_range_set(struct context *context,
403 struct mls_range *range)
404{
405 int l, rc = 0;
406
407 /* Copy the MLS range into the context */
408 for (l = 0; l < 2; l++) {
409 context->range.level[l].sens = range->level[l].sens;
410 rc = ebitmap_cpy(&context->range.level[l].cat,
411 &range->level[l].cat);
412 if (rc)
413 break;
414 }
415
416 return rc;
417}
418
419int mls_setup_user_range(struct context *fromcon, struct user_datum *user,
420 struct context *usercon)
421{
422 if (policydb.mls_enabled) {
423 struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
424 struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
425 struct mls_level *user_low = &(user->range.level[0]);
426 struct mls_level *user_clr = &(user->range.level[1]);
427 struct mls_level *user_def = &(user->dfltlevel);
428 struct mls_level *usercon_sen = &(usercon->range.level[0]);
429 struct mls_level *usercon_clr = &(usercon->range.level[1]);
430
431 /* Honor the user's default level if we can */
432 if (mls_level_between(user_def, fromcon_sen, fromcon_clr))
433 *usercon_sen = *user_def;
434 else if (mls_level_between(fromcon_sen, user_def, user_clr))
435 *usercon_sen = *fromcon_sen;
436 else if (mls_level_between(fromcon_clr, user_low, user_def))
437 *usercon_sen = *user_low;
438 else
439 return -EINVAL;
440
441 /* Lower the clearance of available contexts
442 if the clearance of "fromcon" is lower than
443 that of the user's default clearance (but
444 only if the "fromcon" clearance dominates
445 the user's computed sensitivity level) */
446 if (mls_level_dom(user_clr, fromcon_clr))
447 *usercon_clr = *fromcon_clr;
448 else if (mls_level_dom(fromcon_clr, user_clr))
449 *usercon_clr = *user_clr;
450 else
451 return -EINVAL;
452 }
453
454 return 0;
455}
456
457/*
458 * Convert the MLS fields in the security context
459 * structure `c' from the values specified in the
460 * policy `oldp' to the values specified in the policy `newp'.
461 */
462int mls_convert_context(struct policydb *oldp,
463 struct policydb *newp,
464 struct context *c)
465{
466 struct level_datum *levdatum;
467 struct cat_datum *catdatum;
468 struct ebitmap bitmap;
469 struct ebitmap_node *node;
470 int l, i;
471
472 if (!policydb.mls_enabled)
473 return 0;
474
475 for (l = 0; l < 2; l++) {
476 levdatum = hashtab_search(newp->p_levels.table,
477 sym_name(oldp, SYM_LEVELS,
478 c->range.level[l].sens - 1));
479
480 if (!levdatum)
481 return -EINVAL;
482 c->range.level[l].sens = levdatum->level->sens;
483
484 ebitmap_init(&bitmap);
485 ebitmap_for_each_positive_bit(&c->range.level[l].cat, node, i) {
486 int rc;
487
488 catdatum = hashtab_search(newp->p_cats.table,
489 sym_name(oldp, SYM_CATS, i));
490 if (!catdatum)
491 return -EINVAL;
492 rc = ebitmap_set_bit(&bitmap, catdatum->value - 1, 1);
493 if (rc)
494 return rc;
495
496 cond_resched();
497 }
498 ebitmap_destroy(&c->range.level[l].cat);
499 c->range.level[l].cat = bitmap;
500 }
501
502 return 0;
503}
504
505int mls_compute_sid(struct context *scontext,
506 struct context *tcontext,
507 u16 tclass,
508 u32 specified,
509 struct context *newcontext,
510 bool sock)
511{
512 struct range_trans rtr;
513 struct mls_range *r;
514 struct class_datum *cladatum;
515 int default_range = 0;
516
517 if (!policydb.mls_enabled)
518 return 0;
519
520 switch (specified) {
521 case AVTAB_TRANSITION:
522 /* Look for a range transition rule. */
523 rtr.source_type = scontext->type;
524 rtr.target_type = tcontext->type;
525 rtr.target_class = tclass;
526 r = hashtab_search(policydb.range_tr, &rtr);
527 if (r)
528 return mls_range_set(newcontext, r);
529
530 if (tclass && tclass <= policydb.p_classes.nprim) {
531 cladatum = policydb.class_val_to_struct[tclass - 1];
532 if (cladatum)
533 default_range = cladatum->default_range;
534 }
535
536 switch (default_range) {
537 case DEFAULT_SOURCE_LOW:
538 return mls_context_cpy_low(newcontext, scontext);
539 case DEFAULT_SOURCE_HIGH:
540 return mls_context_cpy_high(newcontext, scontext);
541 case DEFAULT_SOURCE_LOW_HIGH:
542 return mls_context_cpy(newcontext, scontext);
543 case DEFAULT_TARGET_LOW:
544 return mls_context_cpy_low(newcontext, tcontext);
545 case DEFAULT_TARGET_HIGH:
546 return mls_context_cpy_high(newcontext, tcontext);
547 case DEFAULT_TARGET_LOW_HIGH:
548 return mls_context_cpy(newcontext, tcontext);
549 }
550
551 /* Fallthrough */
552 case AVTAB_CHANGE:
553 if ((tclass == policydb.process_class) || (sock == true))
554 /* Use the process MLS attributes. */
555 return mls_context_cpy(newcontext, scontext);
556 else
557 /* Use the process effective MLS attributes. */
558 return mls_context_cpy_low(newcontext, scontext);
559 case AVTAB_MEMBER:
560 /* Use the process effective MLS attributes. */
561 return mls_context_cpy_low(newcontext, scontext);
562
563 /* fall through */
564 }
565 return -EINVAL;
566}
567
568#ifdef CONFIG_NETLABEL
569/**
570 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
571 * @context: the security context
572 * @secattr: the NetLabel security attributes
573 *
574 * Description:
575 * Given the security context copy the low MLS sensitivity level into the
576 * NetLabel MLS sensitivity level field.
577 *
578 */
579void mls_export_netlbl_lvl(struct context *context,
580 struct netlbl_lsm_secattr *secattr)
581{
582 if (!policydb.mls_enabled)
583 return;
584
585 secattr->attr.mls.lvl = context->range.level[0].sens - 1;
586 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
587}
588
589/**
590 * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
591 * @context: the security context
592 * @secattr: the NetLabel security attributes
593 *
594 * Description:
595 * Given the security context and the NetLabel security attributes, copy the
596 * NetLabel MLS sensitivity level into the context.
597 *
598 */
599void mls_import_netlbl_lvl(struct context *context,
600 struct netlbl_lsm_secattr *secattr)
601{
602 if (!policydb.mls_enabled)
603 return;
604
605 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
606 context->range.level[1].sens = context->range.level[0].sens;
607}
608
609/**
610 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
611 * @context: the security context
612 * @secattr: the NetLabel security attributes
613 *
614 * Description:
615 * Given the security context copy the low MLS categories into the NetLabel
616 * MLS category field. Returns zero on success, negative values on failure.
617 *
618 */
619int mls_export_netlbl_cat(struct context *context,
620 struct netlbl_lsm_secattr *secattr)
621{
622 int rc;
623
624 if (!policydb.mls_enabled)
625 return 0;
626
627 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
628 &secattr->attr.mls.cat);
629 if (rc == 0 && secattr->attr.mls.cat != NULL)
630 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
631
632 return rc;
633}
634
635/**
636 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
637 * @context: the security context
638 * @secattr: the NetLabel security attributes
639 *
640 * Description:
641 * Copy the NetLabel security attributes into the SELinux context; since the
642 * NetLabel security attribute only contains a single MLS category use it for
643 * both the low and high categories of the context. Returns zero on success,
644 * negative values on failure.
645 *
646 */
647int mls_import_netlbl_cat(struct context *context,
648 struct netlbl_lsm_secattr *secattr)
649{
650 int rc;
651
652 if (!policydb.mls_enabled)
653 return 0;
654
655 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
656 secattr->attr.mls.cat);
657 if (rc)
658 goto import_netlbl_cat_failure;
659 memcpy(&context->range.level[1].cat, &context->range.level[0].cat,
660 sizeof(context->range.level[0].cat));
661
662 return 0;
663
664import_netlbl_cat_failure:
665 ebitmap_destroy(&context->range.level[0].cat);
666 return rc;
667}
668#endif /* CONFIG_NETLABEL */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Implementation of the multi-level security (MLS) policy.
4 *
5 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
6 */
7/*
8 * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
9 *
10 * Support for enhanced MLS infrastructure.
11 *
12 * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
13 */
14/*
15 * Updated: Hewlett-Packard <paul@paul-moore.com>
16 *
17 * Added support to import/export the MLS label from NetLabel
18 *
19 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
20 */
21
22#include <linux/kernel.h>
23#include <linux/slab.h>
24#include <linux/string.h>
25#include <linux/errno.h>
26#include <net/netlabel.h>
27#include "sidtab.h"
28#include "mls.h"
29#include "policydb.h"
30#include "services.h"
31
32/*
33 * Return the length in bytes for the MLS fields of the
34 * security context string representation of `context'.
35 */
36int mls_compute_context_len(struct policydb *p, struct context *context)
37{
38 int i, l, len, head, prev;
39 char *nm;
40 struct ebitmap *e;
41 struct ebitmap_node *node;
42
43 if (!p->mls_enabled)
44 return 0;
45
46 len = 1; /* for the beginning ":" */
47 for (l = 0; l < 2; l++) {
48 int index_sens = context->range.level[l].sens;
49 len += strlen(sym_name(p, SYM_LEVELS, index_sens - 1));
50
51 /* categories */
52 head = -2;
53 prev = -2;
54 e = &context->range.level[l].cat;
55 ebitmap_for_each_positive_bit(e, node, i) {
56 if (i - prev > 1) {
57 /* one or more negative bits are skipped */
58 if (head != prev) {
59 nm = sym_name(p, SYM_CATS, prev);
60 len += strlen(nm) + 1;
61 }
62 nm = sym_name(p, SYM_CATS, i);
63 len += strlen(nm) + 1;
64 head = i;
65 }
66 prev = i;
67 }
68 if (prev != head) {
69 nm = sym_name(p, SYM_CATS, prev);
70 len += strlen(nm) + 1;
71 }
72 if (l == 0) {
73 if (mls_level_eq(&context->range.level[0],
74 &context->range.level[1]))
75 break;
76 else
77 len++;
78 }
79 }
80
81 return len;
82}
83
84/*
85 * Write the security context string representation of
86 * the MLS fields of `context' into the string `*scontext'.
87 * Update `*scontext' to point to the end of the MLS fields.
88 */
89void mls_sid_to_context(struct policydb *p,
90 struct context *context,
91 char **scontext)
92{
93 char *scontextp, *nm;
94 int i, l, head, prev;
95 struct ebitmap *e;
96 struct ebitmap_node *node;
97
98 if (!p->mls_enabled)
99 return;
100
101 scontextp = *scontext;
102
103 *scontextp = ':';
104 scontextp++;
105
106 for (l = 0; l < 2; l++) {
107 strcpy(scontextp, sym_name(p, SYM_LEVELS,
108 context->range.level[l].sens - 1));
109 scontextp += strlen(scontextp);
110
111 /* categories */
112 head = -2;
113 prev = -2;
114 e = &context->range.level[l].cat;
115 ebitmap_for_each_positive_bit(e, node, i) {
116 if (i - prev > 1) {
117 /* one or more negative bits are skipped */
118 if (prev != head) {
119 if (prev - head > 1)
120 *scontextp++ = '.';
121 else
122 *scontextp++ = ',';
123 nm = sym_name(p, SYM_CATS, prev);
124 strcpy(scontextp, nm);
125 scontextp += strlen(nm);
126 }
127 if (prev < 0)
128 *scontextp++ = ':';
129 else
130 *scontextp++ = ',';
131 nm = sym_name(p, SYM_CATS, i);
132 strcpy(scontextp, nm);
133 scontextp += strlen(nm);
134 head = i;
135 }
136 prev = i;
137 }
138
139 if (prev != head) {
140 if (prev - head > 1)
141 *scontextp++ = '.';
142 else
143 *scontextp++ = ',';
144 nm = sym_name(p, SYM_CATS, prev);
145 strcpy(scontextp, nm);
146 scontextp += strlen(nm);
147 }
148
149 if (l == 0) {
150 if (mls_level_eq(&context->range.level[0],
151 &context->range.level[1]))
152 break;
153 else
154 *scontextp++ = '-';
155 }
156 }
157
158 *scontext = scontextp;
159 return;
160}
161
162int mls_level_isvalid(struct policydb *p, struct mls_level *l)
163{
164 struct level_datum *levdatum;
165
166 if (!l->sens || l->sens > p->p_levels.nprim)
167 return 0;
168 levdatum = 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 */