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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, <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 */