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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/*
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 struct ebitmap_node *node;
164 int i;
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 ebitmap_for_each_positive_bit(&l->cat, node, i) {
174 if (i > p->p_cats.nprim)
175 return 0;
176 if (!ebitmap_get_bit(&levdatum->level->cat, i)) {
177 /*
178 * Category may not be associated with
179 * sensitivity.
180 */
181 return 0;
182 }
183 }
184
185 return 1;
186}
187
188int mls_range_isvalid(struct policydb *p, struct mls_range *r)
189{
190 return (mls_level_isvalid(p, &r->level[0]) &&
191 mls_level_isvalid(p, &r->level[1]) &&
192 mls_level_dom(&r->level[1], &r->level[0]));
193}
194
195/*
196 * Return 1 if the MLS fields in the security context
197 * structure `c' are valid. Return 0 otherwise.
198 */
199int mls_context_isvalid(struct policydb *p, struct context *c)
200{
201 struct user_datum *usrdatum;
202
203 if (!p->mls_enabled)
204 return 1;
205
206 if (!mls_range_isvalid(p, &c->range))
207 return 0;
208
209 if (c->role == OBJECT_R_VAL)
210 return 1;
211
212 /*
213 * User must be authorized for the MLS range.
214 */
215 if (!c->user || c->user > p->p_users.nprim)
216 return 0;
217 usrdatum = p->user_val_to_struct[c->user - 1];
218 if (!mls_range_contains(usrdatum->range, c->range))
219 return 0; /* user may not be associated with range */
220
221 return 1;
222}
223
224/*
225 * Set the MLS fields in the security context structure
226 * `context' based on the string representation in
227 * the string `*scontext'. Update `*scontext' to
228 * point to the end of the string representation of
229 * the MLS fields.
230 *
231 * This function modifies the string in place, inserting
232 * NULL characters to terminate the MLS fields.
233 *
234 * If a def_sid is provided and no MLS field is present,
235 * copy the MLS field of the associated default context.
236 * Used for upgraded to MLS systems where objects may lack
237 * MLS fields.
238 *
239 * Policy read-lock must be held for sidtab lookup.
240 *
241 */
242int mls_context_to_sid(struct policydb *pol,
243 char oldc,
244 char **scontext,
245 struct context *context,
246 struct sidtab *s,
247 u32 def_sid)
248{
249
250 char delim;
251 char *scontextp, *p, *rngptr;
252 struct level_datum *levdatum;
253 struct cat_datum *catdatum, *rngdatum;
254 int l, rc = -EINVAL;
255
256 if (!pol->mls_enabled) {
257 if (def_sid != SECSID_NULL && oldc)
258 *scontext += strlen(*scontext) + 1;
259 return 0;
260 }
261
262 /*
263 * No MLS component to the security context, try and map to
264 * default if provided.
265 */
266 if (!oldc) {
267 struct context *defcon;
268
269 if (def_sid == SECSID_NULL)
270 goto out;
271
272 defcon = sidtab_search(s, def_sid);
273 if (!defcon)
274 goto out;
275
276 rc = mls_context_cpy(context, defcon);
277 goto out;
278 }
279
280 /* Extract low sensitivity. */
281 scontextp = p = *scontext;
282 while (*p && *p != ':' && *p != '-')
283 p++;
284
285 delim = *p;
286 if (delim != '\0')
287 *p++ = '\0';
288
289 for (l = 0; l < 2; l++) {
290 levdatum = hashtab_search(pol->p_levels.table, scontextp);
291 if (!levdatum) {
292 rc = -EINVAL;
293 goto out;
294 }
295
296 context->range.level[l].sens = levdatum->level->sens;
297
298 if (delim == ':') {
299 /* Extract category set. */
300 while (1) {
301 scontextp = p;
302 while (*p && *p != ',' && *p != '-')
303 p++;
304 delim = *p;
305 if (delim != '\0')
306 *p++ = '\0';
307
308 /* Separate into range if exists */
309 rngptr = strchr(scontextp, '.');
310 if (rngptr != NULL) {
311 /* Remove '.' */
312 *rngptr++ = '\0';
313 }
314
315 catdatum = hashtab_search(pol->p_cats.table,
316 scontextp);
317 if (!catdatum) {
318 rc = -EINVAL;
319 goto out;
320 }
321
322 rc = ebitmap_set_bit(&context->range.level[l].cat,
323 catdatum->value - 1, 1);
324 if (rc)
325 goto out;
326
327 /* If range, set all categories in range */
328 if (rngptr) {
329 int i;
330
331 rngdatum = hashtab_search(pol->p_cats.table, rngptr);
332 if (!rngdatum) {
333 rc = -EINVAL;
334 goto out;
335 }
336
337 if (catdatum->value >= rngdatum->value) {
338 rc = -EINVAL;
339 goto out;
340 }
341
342 for (i = catdatum->value; i < rngdatum->value; i++) {
343 rc = ebitmap_set_bit(&context->range.level[l].cat, i, 1);
344 if (rc)
345 goto out;
346 }
347 }
348
349 if (delim != ',')
350 break;
351 }
352 }
353 if (delim == '-') {
354 /* Extract high sensitivity. */
355 scontextp = p;
356 while (*p && *p != ':')
357 p++;
358
359 delim = *p;
360 if (delim != '\0')
361 *p++ = '\0';
362 } else
363 break;
364 }
365
366 if (l == 0) {
367 context->range.level[1].sens = context->range.level[0].sens;
368 rc = ebitmap_cpy(&context->range.level[1].cat,
369 &context->range.level[0].cat);
370 if (rc)
371 goto out;
372 }
373 *scontext = ++p;
374 rc = 0;
375out:
376 return rc;
377}
378
379/*
380 * Set the MLS fields in the security context structure
381 * `context' based on the string representation in
382 * the string `str'. This function will allocate temporary memory with the
383 * given constraints of gfp_mask.
384 */
385int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
386{
387 char *tmpstr, *freestr;
388 int rc;
389
390 if (!policydb.mls_enabled)
391 return -EINVAL;
392
393 /* we need freestr because mls_context_to_sid will change
394 the value of tmpstr */
395 tmpstr = freestr = kstrdup(str, gfp_mask);
396 if (!tmpstr) {
397 rc = -ENOMEM;
398 } else {
399 rc = mls_context_to_sid(&policydb, ':', &tmpstr, context,
400 NULL, SECSID_NULL);
401 kfree(freestr);
402 }
403
404 return rc;
405}
406
407/*
408 * Copies the MLS range `range' into `context'.
409 */
410int mls_range_set(struct context *context,
411 struct mls_range *range)
412{
413 int l, rc = 0;
414
415 /* Copy the MLS range into the context */
416 for (l = 0; l < 2; l++) {
417 context->range.level[l].sens = range->level[l].sens;
418 rc = ebitmap_cpy(&context->range.level[l].cat,
419 &range->level[l].cat);
420 if (rc)
421 break;
422 }
423
424 return rc;
425}
426
427int mls_setup_user_range(struct context *fromcon, struct user_datum *user,
428 struct context *usercon)
429{
430 if (policydb.mls_enabled) {
431 struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
432 struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
433 struct mls_level *user_low = &(user->range.level[0]);
434 struct mls_level *user_clr = &(user->range.level[1]);
435 struct mls_level *user_def = &(user->dfltlevel);
436 struct mls_level *usercon_sen = &(usercon->range.level[0]);
437 struct mls_level *usercon_clr = &(usercon->range.level[1]);
438
439 /* Honor the user's default level if we can */
440 if (mls_level_between(user_def, fromcon_sen, fromcon_clr))
441 *usercon_sen = *user_def;
442 else if (mls_level_between(fromcon_sen, user_def, user_clr))
443 *usercon_sen = *fromcon_sen;
444 else if (mls_level_between(fromcon_clr, user_low, user_def))
445 *usercon_sen = *user_low;
446 else
447 return -EINVAL;
448
449 /* Lower the clearance of available contexts
450 if the clearance of "fromcon" is lower than
451 that of the user's default clearance (but
452 only if the "fromcon" clearance dominates
453 the user's computed sensitivity level) */
454 if (mls_level_dom(user_clr, fromcon_clr))
455 *usercon_clr = *fromcon_clr;
456 else if (mls_level_dom(fromcon_clr, user_clr))
457 *usercon_clr = *user_clr;
458 else
459 return -EINVAL;
460 }
461
462 return 0;
463}
464
465/*
466 * Convert the MLS fields in the security context
467 * structure `c' from the values specified in the
468 * policy `oldp' to the values specified in the policy `newp'.
469 */
470int mls_convert_context(struct policydb *oldp,
471 struct policydb *newp,
472 struct context *c)
473{
474 struct level_datum *levdatum;
475 struct cat_datum *catdatum;
476 struct ebitmap bitmap;
477 struct ebitmap_node *node;
478 int l, i;
479
480 if (!policydb.mls_enabled)
481 return 0;
482
483 for (l = 0; l < 2; l++) {
484 levdatum = hashtab_search(newp->p_levels.table,
485 sym_name(oldp, SYM_LEVELS,
486 c->range.level[l].sens - 1));
487
488 if (!levdatum)
489 return -EINVAL;
490 c->range.level[l].sens = levdatum->level->sens;
491
492 ebitmap_init(&bitmap);
493 ebitmap_for_each_positive_bit(&c->range.level[l].cat, node, i) {
494 int rc;
495
496 catdatum = hashtab_search(newp->p_cats.table,
497 sym_name(oldp, SYM_CATS, i));
498 if (!catdatum)
499 return -EINVAL;
500 rc = ebitmap_set_bit(&bitmap, catdatum->value - 1, 1);
501 if (rc)
502 return rc;
503 }
504 ebitmap_destroy(&c->range.level[l].cat);
505 c->range.level[l].cat = bitmap;
506 }
507
508 return 0;
509}
510
511int mls_compute_sid(struct context *scontext,
512 struct context *tcontext,
513 u16 tclass,
514 u32 specified,
515 struct context *newcontext,
516 bool sock)
517{
518 struct range_trans rtr;
519 struct mls_range *r;
520
521 if (!policydb.mls_enabled)
522 return 0;
523
524 switch (specified) {
525 case AVTAB_TRANSITION:
526 /* Look for a range transition rule. */
527 rtr.source_type = scontext->type;
528 rtr.target_type = tcontext->type;
529 rtr.target_class = tclass;
530 r = hashtab_search(policydb.range_tr, &rtr);
531 if (r)
532 return mls_range_set(newcontext, r);
533 /* Fallthrough */
534 case AVTAB_CHANGE:
535 if ((tclass == policydb.process_class) || (sock == true))
536 /* Use the process MLS attributes. */
537 return mls_context_cpy(newcontext, scontext);
538 else
539 /* Use the process effective MLS attributes. */
540 return mls_context_cpy_low(newcontext, scontext);
541 case AVTAB_MEMBER:
542 /* Use the process effective MLS attributes. */
543 return mls_context_cpy_low(newcontext, scontext);
544
545 /* fall through */
546 }
547 return -EINVAL;
548}
549
550#ifdef CONFIG_NETLABEL
551/**
552 * mls_export_netlbl_lvl - Export the MLS sensitivity levels to NetLabel
553 * @context: the security context
554 * @secattr: the NetLabel security attributes
555 *
556 * Description:
557 * Given the security context copy the low MLS sensitivity level into the
558 * NetLabel MLS sensitivity level field.
559 *
560 */
561void mls_export_netlbl_lvl(struct context *context,
562 struct netlbl_lsm_secattr *secattr)
563{
564 if (!policydb.mls_enabled)
565 return;
566
567 secattr->attr.mls.lvl = context->range.level[0].sens - 1;
568 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
569}
570
571/**
572 * mls_import_netlbl_lvl - Import the NetLabel MLS sensitivity levels
573 * @context: the security context
574 * @secattr: the NetLabel security attributes
575 *
576 * Description:
577 * Given the security context and the NetLabel security attributes, copy the
578 * NetLabel MLS sensitivity level into the context.
579 *
580 */
581void mls_import_netlbl_lvl(struct context *context,
582 struct netlbl_lsm_secattr *secattr)
583{
584 if (!policydb.mls_enabled)
585 return;
586
587 context->range.level[0].sens = secattr->attr.mls.lvl + 1;
588 context->range.level[1].sens = context->range.level[0].sens;
589}
590
591/**
592 * mls_export_netlbl_cat - Export the MLS categories to NetLabel
593 * @context: the security context
594 * @secattr: the NetLabel security attributes
595 *
596 * Description:
597 * Given the security context copy the low MLS categories into the NetLabel
598 * MLS category field. Returns zero on success, negative values on failure.
599 *
600 */
601int mls_export_netlbl_cat(struct context *context,
602 struct netlbl_lsm_secattr *secattr)
603{
604 int rc;
605
606 if (!policydb.mls_enabled)
607 return 0;
608
609 rc = ebitmap_netlbl_export(&context->range.level[0].cat,
610 &secattr->attr.mls.cat);
611 if (rc == 0 && secattr->attr.mls.cat != NULL)
612 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
613
614 return rc;
615}
616
617/**
618 * mls_import_netlbl_cat - Import the MLS categories from NetLabel
619 * @context: the security context
620 * @secattr: the NetLabel security attributes
621 *
622 * Description:
623 * Copy the NetLabel security attributes into the SELinux context; since the
624 * NetLabel security attribute only contains a single MLS category use it for
625 * both the low and high categories of the context. Returns zero on success,
626 * negative values on failure.
627 *
628 */
629int mls_import_netlbl_cat(struct context *context,
630 struct netlbl_lsm_secattr *secattr)
631{
632 int rc;
633
634 if (!policydb.mls_enabled)
635 return 0;
636
637 rc = ebitmap_netlbl_import(&context->range.level[0].cat,
638 secattr->attr.mls.cat);
639 if (rc != 0)
640 goto import_netlbl_cat_failure;
641
642 rc = ebitmap_cpy(&context->range.level[1].cat,
643 &context->range.level[0].cat);
644 if (rc != 0)
645 goto import_netlbl_cat_failure;
646
647 return 0;
648
649import_netlbl_cat_failure:
650 ebitmap_destroy(&context->range.level[0].cat);
651 ebitmap_destroy(&context->range.level[1].cat);
652 return rc;
653}
654#endif /* CONFIG_NETLABEL */