1 /*
2 * Author : Stephen Smalley, <[email protected]>
3 */
4 /*
5 * Updated: Trusted Computer Solutions, Inc. <[email protected]>
6 *
7 * Support for enhanced MLS infrastructure.
8 *
9 * Updated: Frank Mayer <[email protected]>
10 * and Karl MacMillan <[email protected]>
11 *
12 * Added conditional policy language extensions
13 *
14 * Updated: Red Hat, Inc. James Morris <[email protected]>
15 *
16 * Fine-grained netlink support
17 * IPv6 support
18 * Code cleanup
19 *
20 * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
21 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
22 * Copyright (C) 2003 - 2004 Red Hat, Inc.
23 * Copyright (C) 2017 Mellanox Technologies Inc.
24 *
25 * This library is free software; you can redistribute it and/or
26 * modify it under the terms of the GNU Lesser General Public
27 * License as published by the Free Software Foundation; either
28 * version 2.1 of the License, or (at your option) any later version.
29 *
30 * This library is distributed in the hope that it will be useful,
31 * but WITHOUT ANY WARRANTY; without even the implied warranty of
32 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
33 * Lesser General Public License for more details.
34 *
35 * You should have received a copy of the GNU Lesser General Public
36 * License along with this library; if not, write to the Free Software
37 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
38 */
39
40 /* FLASK */
41
42 /*
43 * Implementation of the security services.
44 */
45
46 /* Initial sizes malloc'd for sepol_compute_av_reason_buffer() support */
47 #define REASON_BUF_SIZE 2048
48 #define EXPR_BUF_SIZE 1024
49 #define STACK_LEN 32
50
51 #include <stdlib.h>
52 #include <sys/types.h>
53 #include <sys/socket.h>
54 #include <netinet/in.h>
55 #include <arpa/inet.h>
56
57 #include <sepol/policydb/policydb.h>
58 #include <sepol/policydb/sidtab.h>
59 #include <sepol/policydb/services.h>
60 #include <sepol/policydb/conditional.h>
61 #include <sepol/policydb/util.h>
62 #include <sepol/sepol.h>
63
64 #include "debug.h"
65 #include "private.h"
66 #include "context.h"
67 #include "mls.h"
68 #include "flask.h"
69
70 #define BUG() do { ERR(NULL, "Badness at %s:%d", __FILE__, __LINE__); } while (0)
71
72 static int selinux_enforcing = 1;
73
74 static sidtab_t mysidtab, *sidtab = &mysidtab;
75 static policydb_t mypolicydb, *policydb = &mypolicydb;
76
77 /* Used by sepol_compute_av_reason_buffer() to keep track of entries */
78 static int reason_buf_used;
79 static int reason_buf_len;
80
81 /* Stack services for RPN to infix conversion. */
82 static char **stack;
83 static int stack_len;
84 static int next_stack_entry;
85
push(char * expr_ptr)86 static void push(char *expr_ptr)
87 {
88 if (next_stack_entry >= stack_len) {
89 char **new_stack;
90 int new_stack_len;
91
92 if (stack_len == 0)
93 new_stack_len = STACK_LEN;
94 else
95 new_stack_len = stack_len * 2;
96
97 new_stack = reallocarray(stack, new_stack_len, sizeof(*stack));
98 if (!new_stack) {
99 ERR(NULL, "unable to allocate stack space");
100 return;
101 }
102 stack_len = new_stack_len;
103 stack = new_stack;
104 }
105 stack[next_stack_entry] = expr_ptr;
106 next_stack_entry++;
107 }
108
pop(void)109 static char *pop(void)
110 {
111 next_stack_entry--;
112 if (next_stack_entry < 0) {
113 next_stack_entry = 0;
114 ERR(NULL, "pop called with no stack entries");
115 return NULL;
116 }
117 return stack[next_stack_entry];
118 }
119 /* End Stack services */
120
sepol_set_sidtab(sidtab_t * s)121 int sepol_set_sidtab(sidtab_t * s)
122 {
123 sidtab = s;
124 return 0;
125 }
126
sepol_set_policydb(policydb_t * p)127 int sepol_set_policydb(policydb_t * p)
128 {
129 policydb = p;
130 return 0;
131 }
132
sepol_set_policydb_from_file(FILE * fp)133 int sepol_set_policydb_from_file(FILE * fp)
134 {
135 struct policy_file pf;
136
137 policy_file_init(&pf);
138 pf.fp = fp;
139 pf.type = PF_USE_STDIO;
140 if (mypolicydb.policy_type)
141 policydb_destroy(&mypolicydb);
142 if (policydb_init(&mypolicydb)) {
143 ERR(NULL, "Out of memory!");
144 return -1;
145 }
146 if (policydb_read(&mypolicydb, &pf, 0)) {
147 policydb_destroy(&mypolicydb);
148 ERR(NULL, "can't read binary policy: %m");
149 return -1;
150 }
151 policydb = &mypolicydb;
152 return sepol_sidtab_init(sidtab);
153 }
154
155 /*
156 * The largest sequence number that has been used when
157 * providing an access decision to the access vector cache.
158 * The sequence number only changes when a policy change
159 * occurs.
160 */
161 static uint32_t latest_granting = 0;
162
163 /*
164 * cat_expr_buf adds a string to an expression buffer and handles
165 * realloc's if buffer is too small. The array of expression text
166 * buffer pointers and its counter are globally defined here as
167 * constraint_expr_eval_reason() sets them up and cat_expr_buf
168 * updates the e_buf pointer.
169 */
170 static int expr_counter;
171 static char **expr_list;
172 static int expr_buf_used;
173 static int expr_buf_len;
174
cat_expr_buf(char * e_buf,const char * string)175 static void cat_expr_buf(char *e_buf, const char *string)
176 {
177 int len, new_buf_len;
178 char *p, *new_buf;
179
180 while (1) {
181 p = e_buf + expr_buf_used;
182 len = snprintf(p, expr_buf_len - expr_buf_used, "%s", string);
183 if (len < 0 || len >= expr_buf_len - expr_buf_used) {
184 new_buf_len = expr_buf_len + EXPR_BUF_SIZE;
185 new_buf = realloc(e_buf, new_buf_len);
186 if (!new_buf) {
187 ERR(NULL, "failed to realloc expr buffer");
188 return;
189 }
190 /* Update new ptr in expr list and locally + new len */
191 expr_list[expr_counter] = new_buf;
192 e_buf = new_buf;
193 expr_buf_len = new_buf_len;
194 } else {
195 expr_buf_used += len;
196 return;
197 }
198 }
199 }
200
201 /*
202 * If the POLICY_KERN version is >= POLICYDB_VERSION_CONSTRAINT_NAMES,
203 * then for 'types' only, read the types_names->types list as it will
204 * contain a list of types and attributes that were defined in the
205 * policy source.
206 * For user and role plus types (for policy vers <
207 * POLICYDB_VERSION_CONSTRAINT_NAMES) just read the e->names list.
208 */
get_name_list(constraint_expr_t * e,int type,const char * src,const char * op,int failed)209 static void get_name_list(constraint_expr_t *e, int type,
210 const char *src, const char *op, int failed)
211 {
212 ebitmap_t *types;
213 int rc = 0;
214 unsigned int i;
215 char tmp_buf[128];
216 int counter = 0;
217
218 if (policydb->policy_type == POLICY_KERN &&
219 policydb->policyvers >= POLICYDB_VERSION_CONSTRAINT_NAMES &&
220 type == CEXPR_TYPE)
221 types = &e->type_names->types;
222 else
223 types = &e->names;
224
225 /* Find out how many entries */
226 for (i = ebitmap_startbit(types); i < ebitmap_length(types); i++) {
227 rc = ebitmap_get_bit(types, i);
228 if (rc == 0)
229 continue;
230 else
231 counter++;
232 }
233 snprintf(tmp_buf, sizeof(tmp_buf), "(%s%s", src, op);
234 cat_expr_buf(expr_list[expr_counter], tmp_buf);
235
236 if (counter == 0)
237 cat_expr_buf(expr_list[expr_counter], "<empty_set> ");
238 if (counter > 1)
239 cat_expr_buf(expr_list[expr_counter], " {");
240 if (counter >= 1) {
241 for (i = ebitmap_startbit(types); i < ebitmap_length(types); i++) {
242 rc = ebitmap_get_bit(types, i);
243 if (rc == 0)
244 continue;
245
246 /* Collect entries */
247 switch (type) {
248 case CEXPR_USER:
249 snprintf(tmp_buf, sizeof(tmp_buf), " %s",
250 policydb->p_user_val_to_name[i]);
251 break;
252 case CEXPR_ROLE:
253 snprintf(tmp_buf, sizeof(tmp_buf), " %s",
254 policydb->p_role_val_to_name[i]);
255 break;
256 case CEXPR_TYPE:
257 snprintf(tmp_buf, sizeof(tmp_buf), " %s",
258 policydb->p_type_val_to_name[i]);
259 break;
260 }
261 cat_expr_buf(expr_list[expr_counter], tmp_buf);
262 }
263 }
264 if (counter > 1)
265 cat_expr_buf(expr_list[expr_counter], " }");
266 if (failed)
267 cat_expr_buf(expr_list[expr_counter], " -Fail-) ");
268 else
269 cat_expr_buf(expr_list[expr_counter], ") ");
270
271 return;
272 }
273
msgcat(const char * src,const char * tgt,const char * op,int failed)274 static void msgcat(const char *src, const char *tgt, const char *op, int failed)
275 {
276 char tmp_buf[128];
277 if (failed)
278 snprintf(tmp_buf, sizeof(tmp_buf), "(%s %s %s -Fail-) ",
279 src, op, tgt);
280 else
281 snprintf(tmp_buf, sizeof(tmp_buf), "(%s %s %s) ",
282 src, op, tgt);
283 cat_expr_buf(expr_list[expr_counter], tmp_buf);
284 }
285
286 /* Returns a buffer with class, statement type and permissions */
get_class_info(sepol_security_class_t tclass,constraint_node_t * constraint,context_struct_t * xcontext)287 static char *get_class_info(sepol_security_class_t tclass,
288 constraint_node_t *constraint,
289 context_struct_t *xcontext)
290 {
291 constraint_expr_t *e;
292 int mls, state_num;
293 /* Determine statement type */
294 const char *statements[] = {
295 "constrain ", /* 0 */
296 "mlsconstrain ", /* 1 */
297 "validatetrans ", /* 2 */
298 "mlsvalidatetrans ", /* 3 */
299 0 };
300 size_t class_buf_len = 0;
301 size_t new_class_buf_len;
302 size_t buf_used;
303 int len;
304 char *class_buf = NULL, *p;
305 char *new_class_buf = NULL;
306
307 /* Find if MLS statement or not */
308 mls = 0;
309 for (e = constraint->expr; e; e = e->next) {
310 if (e->attr >= CEXPR_L1L2) {
311 mls = 1;
312 break;
313 }
314 }
315
316 if (xcontext == NULL)
317 state_num = mls + 0;
318 else
319 state_num = mls + 2;
320
321 while (1) {
322 new_class_buf_len = class_buf_len + EXPR_BUF_SIZE;
323 new_class_buf = realloc(class_buf, new_class_buf_len);
324 if (!new_class_buf) {
325 free(class_buf);
326 return NULL;
327 }
328 class_buf_len = new_class_buf_len;
329 class_buf = new_class_buf;
330 buf_used = 0;
331 p = class_buf;
332
333 /* Add statement type */
334 len = snprintf(p, class_buf_len - buf_used, "%s", statements[state_num]);
335 if (len < 0 || (size_t)len >= class_buf_len - buf_used)
336 continue;
337
338 /* Add class entry */
339 p += len;
340 buf_used += len;
341 len = snprintf(p, class_buf_len - buf_used, "%s ",
342 policydb->p_class_val_to_name[tclass - 1]);
343 if (len < 0 || (size_t)len >= class_buf_len - buf_used)
344 continue;
345
346 /* Add permission entries (validatetrans does not have perms) */
347 p += len;
348 buf_used += len;
349 if (state_num < 2) {
350 char *permstr = sepol_av_to_string(policydb, tclass, constraint->permissions);
351
352 len = snprintf(p, class_buf_len - buf_used, "{%s } (",
353 permstr ?: "<format-failure>");
354 free(permstr);
355 } else {
356 len = snprintf(p, class_buf_len - buf_used, "(");
357 }
358 if (len < 0 || (size_t)len >= class_buf_len - buf_used)
359 continue;
360 break;
361 }
362 return class_buf;
363 }
364
365 /*
366 * Modified version of constraint_expr_eval that will process each
367 * constraint as before but adds the information to text buffers that
368 * will hold various components. The expression will be in RPN format,
369 * therefore there is a stack based RPN to infix converter to produce
370 * the final readable constraint.
371 *
372 * Return the boolean value of a constraint expression
373 * when it is applied to the specified source and target
374 * security contexts.
375 *
376 * xcontext is a special beast... It is used by the validatetrans rules
377 * only. For these rules, scontext is the context before the transition,
378 * tcontext is the context after the transition, and xcontext is the
379 * context of the process performing the transition. All other callers
380 * of constraint_expr_eval_reason should pass in NULL for xcontext.
381 *
382 * This function will also build a buffer as the constraint is processed
383 * for analysis. If this option is not required, then:
384 * 'tclass' should be '0' and r_buf MUST be NULL.
385 */
constraint_expr_eval_reason(context_struct_t * scontext,context_struct_t * tcontext,context_struct_t * xcontext,sepol_security_class_t tclass,constraint_node_t * constraint,char ** r_buf,unsigned int flags)386 static int constraint_expr_eval_reason(context_struct_t *scontext,
387 context_struct_t *tcontext,
388 context_struct_t *xcontext,
389 sepol_security_class_t tclass,
390 constraint_node_t *constraint,
391 char **r_buf,
392 unsigned int flags)
393 {
394 uint32_t val1, val2;
395 context_struct_t *c;
396 role_datum_t *r1, *r2;
397 mls_level_t *l1, *l2;
398 constraint_expr_t *e;
399 int s[CEXPR_MAXDEPTH] = {};
400 int sp = -1;
401 char tmp_buf[128];
402
403 /*
404 * Define the s_t_x_num values that make up r1, t2 etc. in text strings
405 * Set 1 = source, 2 = target, 3 = xcontext for validatetrans
406 */
407 #define SOURCE 1
408 #define TARGET 2
409 #define XTARGET 3
410
411 int s_t_x_num;
412
413 /* Set 0 = fail, u = CEXPR_USER, r = CEXPR_ROLE, t = CEXPR_TYPE */
414 int u_r_t = 0;
415
416 char *src = NULL;
417 char *tgt = NULL;
418 int rc = 0, x;
419 char *class_buf = NULL;
420 int expr_list_len = 0;
421 int expr_count;
422
423 /*
424 * The array of expression answer buffer pointers and counter.
425 */
426 char **answer_list = NULL;
427 int answer_counter = 0;
428
429 /* The pop operands */
430 char *a;
431 char *b;
432 int a_len, b_len;
433
434 class_buf = get_class_info(tclass, constraint, xcontext);
435 if (!class_buf) {
436 ERR(NULL, "failed to allocate class buffer");
437 return -ENOMEM;
438 }
439
440 /* Original function but with buffer support */
441 expr_counter = 0;
442 expr_list = NULL;
443 for (e = constraint->expr; e; e = e->next) {
444 /* Allocate a stack to hold expression buffer entries */
445 if (expr_counter >= expr_list_len) {
446 char **new_expr_list;
447 int new_expr_list_len;
448
449 if (expr_list_len == 0)
450 new_expr_list_len = STACK_LEN;
451 else
452 new_expr_list_len = expr_list_len * 2;
453
454 new_expr_list = reallocarray(expr_list,
455 new_expr_list_len, sizeof(*expr_list));
456 if (!new_expr_list) {
457 ERR(NULL, "failed to allocate expr buffer stack");
458 rc = -ENOMEM;
459 goto out;
460 }
461 expr_list_len = new_expr_list_len;
462 expr_list = new_expr_list;
463 }
464
465 /*
466 * malloc a buffer to store each expression text component. If
467 * buffer is too small cat_expr_buf() will realloc extra space.
468 */
469 expr_buf_len = EXPR_BUF_SIZE;
470 expr_list[expr_counter] = malloc(expr_buf_len);
471 if (!expr_list[expr_counter]) {
472 ERR(NULL, "failed to allocate expr buffer");
473 rc = -ENOMEM;
474 goto out;
475 }
476 expr_buf_used = 0;
477
478 /* Now process each expression of the constraint */
479 switch (e->expr_type) {
480 case CEXPR_NOT:
481 if (sp < 0) {
482 BUG();
483 rc = -EINVAL;
484 goto out;
485 }
486 s[sp] = !s[sp];
487 cat_expr_buf(expr_list[expr_counter], "not");
488 break;
489 case CEXPR_AND:
490 if (sp < 1) {
491 BUG();
492 rc = -EINVAL;
493 goto out;
494 }
495 sp--;
496 s[sp] &= s[sp + 1];
497 cat_expr_buf(expr_list[expr_counter], "and");
498 break;
499 case CEXPR_OR:
500 if (sp < 1) {
501 BUG();
502 rc = -EINVAL;
503 goto out;
504 }
505 sp--;
506 s[sp] |= s[sp + 1];
507 cat_expr_buf(expr_list[expr_counter], "or");
508 break;
509 case CEXPR_ATTR:
510 if (sp == (CEXPR_MAXDEPTH - 1))
511 goto out;
512
513 switch (e->attr) {
514 case CEXPR_USER:
515 val1 = scontext->user;
516 val2 = tcontext->user;
517 free(src); src = strdup("u1");
518 free(tgt); tgt = strdup("u2");
519 break;
520 case CEXPR_TYPE:
521 val1 = scontext->type;
522 val2 = tcontext->type;
523 free(src); src = strdup("t1");
524 free(tgt); tgt = strdup("t2");
525 break;
526 case CEXPR_ROLE:
527 val1 = scontext->role;
528 val2 = tcontext->role;
529 r1 = policydb->role_val_to_struct[val1 - 1];
530 r2 = policydb->role_val_to_struct[val2 - 1];
531 free(src); src = strdup("r1");
532 free(tgt); tgt = strdup("r2");
533
534 switch (e->op) {
535 case CEXPR_DOM:
536 s[++sp] = ebitmap_get_bit(&r1->dominates, val2 - 1);
537 msgcat(src, tgt, "dom", s[sp] == 0);
538 expr_counter++;
539 continue;
540 case CEXPR_DOMBY:
541 s[++sp] = ebitmap_get_bit(&r2->dominates, val1 - 1);
542 msgcat(src, tgt, "domby", s[sp] == 0);
543 expr_counter++;
544 continue;
545 case CEXPR_INCOMP:
546 s[++sp] = (!ebitmap_get_bit(&r1->dominates, val2 - 1)
547 && !ebitmap_get_bit(&r2->dominates, val1 - 1));
548 msgcat(src, tgt, "incomp", s[sp] == 0);
549 expr_counter++;
550 continue;
551 default:
552 break;
553 }
554 break;
555 case CEXPR_L1L2:
556 l1 = &(scontext->range.level[0]);
557 l2 = &(tcontext->range.level[0]);
558 free(src); src = strdup("l1");
559 free(tgt); tgt = strdup("l2");
560 goto mls_ops;
561 case CEXPR_L1H2:
562 l1 = &(scontext->range.level[0]);
563 l2 = &(tcontext->range.level[1]);
564 free(src); src = strdup("l1");
565 free(tgt); tgt = strdup("h2");
566 goto mls_ops;
567 case CEXPR_H1L2:
568 l1 = &(scontext->range.level[1]);
569 l2 = &(tcontext->range.level[0]);
570 free(src); src = strdup("h1");
571 free(tgt); tgt = strdup("l2");
572 goto mls_ops;
573 case CEXPR_H1H2:
574 l1 = &(scontext->range.level[1]);
575 l2 = &(tcontext->range.level[1]);
576 free(src); src = strdup("h1");
577 free(tgt); tgt = strdup("h2");
578 goto mls_ops;
579 case CEXPR_L1H1:
580 l1 = &(scontext->range.level[0]);
581 l2 = &(scontext->range.level[1]);
582 free(src); src = strdup("l1");
583 free(tgt); tgt = strdup("h1");
584 goto mls_ops;
585 case CEXPR_L2H2:
586 l1 = &(tcontext->range.level[0]);
587 l2 = &(tcontext->range.level[1]);
588 free(src); src = strdup("l2");
589 free(tgt); tgt = strdup("h2");
590 mls_ops:
591 switch (e->op) {
592 case CEXPR_EQ:
593 s[++sp] = mls_level_eq(l1, l2);
594 msgcat(src, tgt, "eq", s[sp] == 0);
595 expr_counter++;
596 continue;
597 case CEXPR_NEQ:
598 s[++sp] = !mls_level_eq(l1, l2);
599 msgcat(src, tgt, "!=", s[sp] == 0);
600 expr_counter++;
601 continue;
602 case CEXPR_DOM:
603 s[++sp] = mls_level_dom(l1, l2);
604 msgcat(src, tgt, "dom", s[sp] == 0);
605 expr_counter++;
606 continue;
607 case CEXPR_DOMBY:
608 s[++sp] = mls_level_dom(l2, l1);
609 msgcat(src, tgt, "domby", s[sp] == 0);
610 expr_counter++;
611 continue;
612 case CEXPR_INCOMP:
613 s[++sp] = mls_level_incomp(l2, l1);
614 msgcat(src, tgt, "incomp", s[sp] == 0);
615 expr_counter++;
616 continue;
617 default:
618 BUG();
619 goto out;
620 }
621 break;
622 default:
623 BUG();
624 goto out;
625 }
626
627 switch (e->op) {
628 case CEXPR_EQ:
629 s[++sp] = (val1 == val2);
630 msgcat(src, tgt, "==", s[sp] == 0);
631 break;
632 case CEXPR_NEQ:
633 s[++sp] = (val1 != val2);
634 msgcat(src, tgt, "!=", s[sp] == 0);
635 break;
636 default:
637 BUG();
638 goto out;
639 }
640 break;
641 case CEXPR_NAMES:
642 if (sp == (CEXPR_MAXDEPTH - 1))
643 goto out;
644 s_t_x_num = SOURCE;
645 c = scontext;
646 if (e->attr & CEXPR_TARGET) {
647 s_t_x_num = TARGET;
648 c = tcontext;
649 } else if (e->attr & CEXPR_XTARGET) {
650 s_t_x_num = XTARGET;
651 c = xcontext;
652 }
653 if (!c) {
654 BUG();
655 goto out;
656 }
657 if (e->attr & CEXPR_USER) {
658 u_r_t = CEXPR_USER;
659 val1 = c->user;
660 snprintf(tmp_buf, sizeof(tmp_buf), "u%d ", s_t_x_num);
661 free(src); src = strdup(tmp_buf);
662 } else if (e->attr & CEXPR_ROLE) {
663 u_r_t = CEXPR_ROLE;
664 val1 = c->role;
665 snprintf(tmp_buf, sizeof(tmp_buf), "r%d ", s_t_x_num);
666 free(src); src = strdup(tmp_buf);
667 } else if (e->attr & CEXPR_TYPE) {
668 u_r_t = CEXPR_TYPE;
669 val1 = c->type;
670 snprintf(tmp_buf, sizeof(tmp_buf), "t%d ", s_t_x_num);
671 free(src); src = strdup(tmp_buf);
672 } else {
673 BUG();
674 goto out;
675 }
676
677 switch (e->op) {
678 case CEXPR_EQ:
679 s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
680 get_name_list(e, u_r_t, src, "==", s[sp] == 0);
681 break;
682
683 case CEXPR_NEQ:
684 s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
685 get_name_list(e, u_r_t, src, "!=", s[sp] == 0);
686 break;
687 default:
688 BUG();
689 goto out;
690 }
691 break;
692 default:
693 BUG();
694 goto out;
695 }
696 expr_counter++;
697 }
698
699 /*
700 * At this point each expression of the constraint is in
701 * expr_list[n+1] and in RPN format. Now convert to 'infix'
702 */
703
704 /*
705 * Save expr count but zero expr_counter to detect if
706 * 'BUG(); goto out;' was called as we need to release any used
707 * expr_list malloc's. Normally they are released by the RPN to
708 * infix code.
709 */
710 expr_count = expr_counter;
711 expr_counter = 0;
712
713 /*
714 * Generate the same number of answer buffer entries as expression
715 * buffers (as there will never be more).
716 */
717 answer_list = calloc(expr_count, sizeof(*answer_list));
718 if (!answer_list) {
719 ERR(NULL, "failed to allocate answer stack");
720 rc = -ENOMEM;
721 goto out;
722 }
723
724 /* Convert constraint from RPN to infix notation. */
725 for (x = 0; x != expr_count; x++) {
726 if (strncmp(expr_list[x], "and", 3) == 0 || strncmp(expr_list[x],
727 "or", 2) == 0) {
728 b = pop();
729 b_len = strlen(b);
730 a = pop();
731 a_len = strlen(a);
732
733 /* get a buffer to hold the answer */
734 answer_list[answer_counter] = malloc(a_len + b_len + 8);
735 if (!answer_list[answer_counter]) {
736 ERR(NULL, "failed to allocate answer buffer");
737 rc = -ENOMEM;
738 goto out;
739 }
740 memset(answer_list[answer_counter], '\0', a_len + b_len + 8);
741
742 sprintf(answer_list[answer_counter], "%s %s %s", a,
743 expr_list[x], b);
744 push(answer_list[answer_counter++]);
745 free(a);
746 free(b);
747 free(expr_list[x]);
748 } else if (strncmp(expr_list[x], "not", 3) == 0) {
749 b = pop();
750 b_len = strlen(b);
751
752 answer_list[answer_counter] = malloc(b_len + 8);
753 if (!answer_list[answer_counter]) {
754 ERR(NULL, "failed to allocate answer buffer");
755 rc = -ENOMEM;
756 goto out;
757 }
758 memset(answer_list[answer_counter], '\0', b_len + 8);
759
760 if (strncmp(b, "not", 3) == 0)
761 sprintf(answer_list[answer_counter], "%s (%s)",
762 expr_list[x], b);
763 else
764 sprintf(answer_list[answer_counter], "%s%s",
765 expr_list[x], b);
766 push(answer_list[answer_counter++]);
767 free(b);
768 free(expr_list[x]);
769 } else {
770 push(expr_list[x]);
771 }
772 }
773 /* Get the final answer from tos and build constraint text */
774 a = pop();
775
776 /* validatetrans / constraint calculation:
777 rc = 0 is denied, rc = 1 is granted */
778 sprintf(tmp_buf, "%s %s\n",
779 xcontext ? "Validatetrans" : "Constraint",
780 s[0] ? "GRANTED" : "DENIED");
781
782 /*
783 * This will add the constraints to the callers reason buffer (who is
784 * responsible for freeing the memory). It will handle any realloc's
785 * should the buffer be too short.
786 * The reason_buf_used and reason_buf_len counters are defined
787 * globally as multiple constraints can be in the buffer.
788 */
789
790 if (r_buf && ((s[0] == 0) || ((s[0] == 1 &&
791 (flags & SHOW_GRANTED) == SHOW_GRANTED)))) {
792 int len;
793 char *p;
794 /*
795 * These contain the constraint components that are added to the
796 * callers reason buffer.
797 */
798 const char *buffers[] = { class_buf, a, "); ", tmp_buf, 0 };
799
800 for (x = 0; buffers[x] != NULL; x++) {
801 while (1) {
802 p = *r_buf ? (*r_buf + reason_buf_used) : NULL;
803 len = snprintf(p, reason_buf_len - reason_buf_used,
804 "%s", buffers[x]);
805 if (len < 0 || len >= reason_buf_len - reason_buf_used) {
806 int new_buf_len = reason_buf_len + REASON_BUF_SIZE;
807 char *new_buf = realloc(*r_buf, new_buf_len);
808 if (!new_buf) {
809 ERR(NULL, "failed to realloc reason buffer");
810 goto out1;
811 }
812 *r_buf = new_buf;
813 reason_buf_len = new_buf_len;
814 continue;
815 } else {
816 reason_buf_used += len;
817 break;
818 }
819 }
820 }
821 }
822
823 out1:
824 rc = s[0];
825 free(a);
826
827 out:
828 free(class_buf);
829 free(src);
830 free(tgt);
831
832 if (expr_counter) {
833 for (x = 0; expr_list[x] != NULL; x++)
834 free(expr_list[x]);
835 }
836 free(answer_list);
837 free(expr_list);
838 return rc;
839 }
840
841 /* Forward declaration */
842 static int context_struct_compute_av(context_struct_t * scontext,
843 context_struct_t * tcontext,
844 sepol_security_class_t tclass,
845 sepol_access_vector_t requested,
846 struct sepol_av_decision *avd,
847 unsigned int *reason,
848 char **r_buf,
849 unsigned int flags);
850
type_attribute_bounds_av(context_struct_t * scontext,context_struct_t * tcontext,sepol_security_class_t tclass,sepol_access_vector_t requested,struct sepol_av_decision * avd,unsigned int * reason)851 static void type_attribute_bounds_av(context_struct_t *scontext,
852 context_struct_t *tcontext,
853 sepol_security_class_t tclass,
854 sepol_access_vector_t requested,
855 struct sepol_av_decision *avd,
856 unsigned int *reason)
857 {
858 context_struct_t lo_scontext;
859 context_struct_t lo_tcontext, *tcontextp = tcontext;
860 struct sepol_av_decision lo_avd;
861 type_datum_t *source;
862 type_datum_t *target;
863 sepol_access_vector_t masked = 0;
864
865 source = policydb->type_val_to_struct[scontext->type - 1];
866 if (!source->bounds)
867 return;
868
869 target = policydb->type_val_to_struct[tcontext->type - 1];
870
871 memset(&lo_avd, 0, sizeof(lo_avd));
872
873 memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
874 lo_scontext.type = source->bounds;
875
876 if (target->bounds) {
877 memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
878 lo_tcontext.type = target->bounds;
879 tcontextp = &lo_tcontext;
880 }
881
882 context_struct_compute_av(&lo_scontext,
883 tcontextp,
884 tclass,
885 requested,
886 &lo_avd,
887 NULL, /* reason intentionally omitted */
888 NULL,
889 0);
890
891 masked = ~lo_avd.allowed & avd->allowed;
892
893 if (!masked)
894 return; /* no masked permission */
895
896 /* mask violated permissions */
897 avd->allowed &= ~masked;
898
899 if (reason)
900 *reason |= SEPOL_COMPUTEAV_BOUNDS;
901 }
902
903 /*
904 * Compute access vectors based on a context structure pair for
905 * the permissions in a particular class.
906 */
context_struct_compute_av(context_struct_t * scontext,context_struct_t * tcontext,sepol_security_class_t tclass,sepol_access_vector_t requested,struct sepol_av_decision * avd,unsigned int * reason,char ** r_buf,unsigned int flags)907 static int context_struct_compute_av(context_struct_t * scontext,
908 context_struct_t * tcontext,
909 sepol_security_class_t tclass,
910 sepol_access_vector_t requested,
911 struct sepol_av_decision *avd,
912 unsigned int *reason,
913 char **r_buf,
914 unsigned int flags)
915 {
916 constraint_node_t *constraint;
917 struct role_allow *ra;
918 avtab_key_t avkey;
919 class_datum_t *tclass_datum;
920 avtab_ptr_t node;
921 ebitmap_t *sattr, *tattr;
922 ebitmap_node_t *snode, *tnode;
923 unsigned int i, j;
924
925 if (!tclass || tclass > policydb->p_classes.nprim) {
926 ERR(NULL, "unrecognized class %d", tclass);
927 return -EINVAL;
928 }
929 tclass_datum = policydb->class_val_to_struct[tclass - 1];
930
931 /*
932 * Initialize the access vectors to the default values.
933 */
934 avd->allowed = 0;
935 avd->decided = 0xffffffff;
936 avd->auditallow = 0;
937 avd->auditdeny = 0xffffffff;
938 avd->seqno = latest_granting;
939 if (reason)
940 *reason = 0;
941
942 /*
943 * If a specific type enforcement rule was defined for
944 * this permission check, then use it.
945 */
946 avkey.target_class = tclass;
947 avkey.specified = AVTAB_AV;
948 sattr = &policydb->type_attr_map[scontext->type - 1];
949 tattr = &policydb->type_attr_map[tcontext->type - 1];
950 ebitmap_for_each_positive_bit(sattr, snode, i) {
951 ebitmap_for_each_positive_bit(tattr, tnode, j) {
952 avkey.source_type = i + 1;
953 avkey.target_type = j + 1;
954 for (node =
955 avtab_search_node(&policydb->te_avtab, &avkey);
956 node != NULL;
957 node =
958 avtab_search_node_next(node, avkey.specified)) {
959 if (node->key.specified == AVTAB_ALLOWED)
960 avd->allowed |= node->datum.data;
961 else if (node->key.specified ==
962 AVTAB_AUDITALLOW)
963 avd->auditallow |= node->datum.data;
964 else if (node->key.specified == AVTAB_AUDITDENY)
965 avd->auditdeny &= node->datum.data;
966 }
967
968 /* Check conditional av table for additional permissions */
969 cond_compute_av(&policydb->te_cond_avtab, &avkey, avd);
970
971 }
972 }
973
974 if (requested & ~avd->allowed) {
975 if (reason)
976 *reason |= SEPOL_COMPUTEAV_TE;
977 requested &= avd->allowed;
978 }
979
980 /*
981 * Remove any permissions prohibited by a constraint (this includes
982 * the MLS policy).
983 */
984 constraint = tclass_datum->constraints;
985 while (constraint) {
986 if ((constraint->permissions & (avd->allowed)) &&
987 !constraint_expr_eval_reason(scontext, tcontext, NULL,
988 tclass, constraint, r_buf, flags)) {
989 avd->allowed =
990 (avd->allowed) & ~(constraint->permissions);
991 }
992 constraint = constraint->next;
993 }
994
995 if (requested & ~avd->allowed) {
996 if (reason)
997 *reason |= SEPOL_COMPUTEAV_CONS;
998 requested &= avd->allowed;
999 }
1000
1001 /*
1002 * If checking process transition permission and the
1003 * role is changing, then check the (current_role, new_role)
1004 * pair.
1005 */
1006 if (tclass == policydb->process_class &&
1007 (avd->allowed & policydb->process_trans_dyntrans) &&
1008 scontext->role != tcontext->role) {
1009 for (ra = policydb->role_allow; ra; ra = ra->next) {
1010 if (scontext->role == ra->role &&
1011 tcontext->role == ra->new_role)
1012 break;
1013 }
1014 if (!ra)
1015 avd->allowed &= ~policydb->process_trans_dyntrans;
1016 }
1017
1018 if (requested & ~avd->allowed) {
1019 if (reason)
1020 *reason |= SEPOL_COMPUTEAV_RBAC;
1021 requested &= avd->allowed;
1022 }
1023
1024 type_attribute_bounds_av(scontext, tcontext, tclass, requested, avd,
1025 reason);
1026 return 0;
1027 }
1028
1029 /*
1030 * sepol_validate_transition_reason_buffer - the reason buffer is realloc'd
1031 * in the constraint_expr_eval_reason() function.
1032 */
sepol_validate_transition_reason_buffer(sepol_security_id_t oldsid,sepol_security_id_t newsid,sepol_security_id_t tasksid,sepol_security_class_t tclass,char ** reason_buf,unsigned int flags)1033 int sepol_validate_transition_reason_buffer(sepol_security_id_t oldsid,
1034 sepol_security_id_t newsid,
1035 sepol_security_id_t tasksid,
1036 sepol_security_class_t tclass,
1037 char **reason_buf,
1038 unsigned int flags)
1039 {
1040 context_struct_t *ocontext;
1041 context_struct_t *ncontext;
1042 context_struct_t *tcontext;
1043 class_datum_t *tclass_datum;
1044 constraint_node_t *constraint;
1045
1046 if (!tclass || tclass > policydb->p_classes.nprim) {
1047 ERR(NULL, "unrecognized class %d", tclass);
1048 return -EINVAL;
1049 }
1050 tclass_datum = policydb->class_val_to_struct[tclass - 1];
1051
1052 ocontext = sepol_sidtab_search(sidtab, oldsid);
1053 if (!ocontext) {
1054 ERR(NULL, "unrecognized SID %d", oldsid);
1055 return -EINVAL;
1056 }
1057
1058 ncontext = sepol_sidtab_search(sidtab, newsid);
1059 if (!ncontext) {
1060 ERR(NULL, "unrecognized SID %d", newsid);
1061 return -EINVAL;
1062 }
1063
1064 tcontext = sepol_sidtab_search(sidtab, tasksid);
1065 if (!tcontext) {
1066 ERR(NULL, "unrecognized SID %d", tasksid);
1067 return -EINVAL;
1068 }
1069
1070 /*
1071 * Set the buffer to NULL as mls/validatetrans may not be processed.
1072 * If a buffer is required, then the routines in
1073 * constraint_expr_eval_reason will realloc in REASON_BUF_SIZE
1074 * chunks (as it gets called for each mls/validatetrans processed).
1075 * We just make sure these start from zero.
1076 */
1077 *reason_buf = NULL;
1078 reason_buf_used = 0;
1079 reason_buf_len = 0;
1080 constraint = tclass_datum->validatetrans;
1081 while (constraint) {
1082 if (!constraint_expr_eval_reason(ocontext, ncontext, tcontext,
1083 tclass, constraint, reason_buf, flags)) {
1084 return -EPERM;
1085 }
1086 constraint = constraint->next;
1087 }
1088 return 0;
1089 }
1090
sepol_compute_av_reason(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,sepol_access_vector_t requested,struct sepol_av_decision * avd,unsigned int * reason)1091 int sepol_compute_av_reason(sepol_security_id_t ssid,
1092 sepol_security_id_t tsid,
1093 sepol_security_class_t tclass,
1094 sepol_access_vector_t requested,
1095 struct sepol_av_decision *avd,
1096 unsigned int *reason)
1097 {
1098 context_struct_t *scontext = 0, *tcontext = 0;
1099 int rc = 0;
1100
1101 scontext = sepol_sidtab_search(sidtab, ssid);
1102 if (!scontext) {
1103 ERR(NULL, "unrecognized source SID %d", ssid);
1104 rc = -EINVAL;
1105 goto out;
1106 }
1107 tcontext = sepol_sidtab_search(sidtab, tsid);
1108 if (!tcontext) {
1109 ERR(NULL, "unrecognized target SID %d", tsid);
1110 rc = -EINVAL;
1111 goto out;
1112 }
1113
1114 rc = context_struct_compute_av(scontext, tcontext, tclass,
1115 requested, avd, reason, NULL, 0);
1116 out:
1117 return rc;
1118 }
1119
1120 /*
1121 * sepol_compute_av_reason_buffer - the reason buffer is malloc'd to
1122 * REASON_BUF_SIZE. If the buffer size is exceeded, then it is realloc'd
1123 * in the constraint_expr_eval_reason() function.
1124 */
sepol_compute_av_reason_buffer(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,sepol_access_vector_t requested,struct sepol_av_decision * avd,unsigned int * reason,char ** reason_buf,unsigned int flags)1125 int sepol_compute_av_reason_buffer(sepol_security_id_t ssid,
1126 sepol_security_id_t tsid,
1127 sepol_security_class_t tclass,
1128 sepol_access_vector_t requested,
1129 struct sepol_av_decision *avd,
1130 unsigned int *reason,
1131 char **reason_buf,
1132 unsigned int flags)
1133 {
1134 context_struct_t *scontext = 0, *tcontext = 0;
1135 int rc = 0;
1136
1137 scontext = sepol_sidtab_search(sidtab, ssid);
1138 if (!scontext) {
1139 ERR(NULL, "unrecognized source SID %d", ssid);
1140 rc = -EINVAL;
1141 goto out;
1142 }
1143 tcontext = sepol_sidtab_search(sidtab, tsid);
1144 if (!tcontext) {
1145 ERR(NULL, "unrecognized target SID %d", tsid);
1146 rc = -EINVAL;
1147 goto out;
1148 }
1149
1150 /*
1151 * Set the buffer to NULL as constraints may not be processed.
1152 * If a buffer is required, then the routines in
1153 * constraint_expr_eval_reason will realloc in REASON_BUF_SIZE
1154 * chunks (as it gets called for each constraint processed).
1155 * We just make sure these start from zero.
1156 */
1157 *reason_buf = NULL;
1158 reason_buf_used = 0;
1159 reason_buf_len = 0;
1160
1161 rc = context_struct_compute_av(scontext, tcontext, tclass,
1162 requested, avd, reason, reason_buf, flags);
1163 out:
1164 return rc;
1165 }
1166
sepol_compute_av(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,sepol_access_vector_t requested,struct sepol_av_decision * avd)1167 int sepol_compute_av(sepol_security_id_t ssid,
1168 sepol_security_id_t tsid,
1169 sepol_security_class_t tclass,
1170 sepol_access_vector_t requested,
1171 struct sepol_av_decision *avd)
1172 {
1173 unsigned int reason = 0;
1174 return sepol_compute_av_reason(ssid, tsid, tclass, requested, avd,
1175 &reason);
1176 }
1177
1178 /*
1179 * Return a class ID associated with the class string specified by
1180 * class_name.
1181 */
sepol_string_to_security_class(const char * class_name,sepol_security_class_t * tclass)1182 int sepol_string_to_security_class(const char *class_name,
1183 sepol_security_class_t *tclass)
1184 {
1185 class_datum_t *tclass_datum;
1186
1187 tclass_datum = hashtab_search(policydb->p_classes.table,
1188 class_name);
1189 if (!tclass_datum) {
1190 ERR(NULL, "unrecognized class %s", class_name);
1191 return STATUS_ERR;
1192 }
1193 *tclass = tclass_datum->s.value;
1194 return STATUS_SUCCESS;
1195 }
1196
1197 /*
1198 * Return access vector bit associated with the class ID and permission
1199 * string.
1200 */
sepol_string_to_av_perm(sepol_security_class_t tclass,const char * perm_name,sepol_access_vector_t * av)1201 int sepol_string_to_av_perm(sepol_security_class_t tclass,
1202 const char *perm_name,
1203 sepol_access_vector_t *av)
1204 {
1205 class_datum_t *tclass_datum;
1206 perm_datum_t *perm_datum;
1207
1208 if (!tclass || tclass > policydb->p_classes.nprim) {
1209 ERR(NULL, "unrecognized class %d", tclass);
1210 return -EINVAL;
1211 }
1212 tclass_datum = policydb->class_val_to_struct[tclass - 1];
1213
1214 /* Check for unique perms then the common ones (if any) */
1215 perm_datum = (perm_datum_t *)
1216 hashtab_search(tclass_datum->permissions.table,
1217 perm_name);
1218 if (perm_datum != NULL) {
1219 *av = UINT32_C(1) << (perm_datum->s.value - 1);
1220 return STATUS_SUCCESS;
1221 }
1222
1223 if (tclass_datum->comdatum == NULL)
1224 goto out;
1225
1226 perm_datum = (perm_datum_t *)
1227 hashtab_search(tclass_datum->comdatum->permissions.table,
1228 perm_name);
1229
1230 if (perm_datum != NULL) {
1231 *av = UINT32_C(1) << (perm_datum->s.value - 1);
1232 return STATUS_SUCCESS;
1233 }
1234 out:
1235 ERR(NULL, "could not convert %s to av bit", perm_name);
1236 return STATUS_ERR;
1237 }
1238
sepol_av_perm_to_string(sepol_security_class_t tclass,sepol_access_vector_t av)1239 const char *sepol_av_perm_to_string(sepol_security_class_t tclass,
1240 sepol_access_vector_t av)
1241 {
1242 static char avbuf[1024];
1243 char *avstr = sepol_av_to_string(policydb, tclass, av);
1244 size_t len;
1245
1246 memset(avbuf, 0, sizeof(avbuf));
1247
1248 if (avstr) {
1249 len = strlen(avstr);
1250 if (len < sizeof(avbuf)) {
1251 strcpy(avbuf, avstr);
1252 } else {
1253 sprintf(avbuf, "<access-vector overflowed buffer>");
1254 }
1255 free(avstr);
1256 } else {
1257 sprintf(avbuf, "<format-failure>");
1258 }
1259
1260 return avbuf;
1261 }
1262
1263 /*
1264 * Write the security context string representation of
1265 * the context associated with `sid' into a dynamically
1266 * allocated string of the correct size. Set `*scontext'
1267 * to point to this string and set `*scontext_len' to
1268 * the length of the string.
1269 */
sepol_sid_to_context(sepol_security_id_t sid,sepol_security_context_t * scontext,size_t * scontext_len)1270 int sepol_sid_to_context(sepol_security_id_t sid,
1271 sepol_security_context_t * scontext,
1272 size_t * scontext_len)
1273 {
1274 context_struct_t *context;
1275 int rc = 0;
1276
1277 context = sepol_sidtab_search(sidtab, sid);
1278 if (!context) {
1279 ERR(NULL, "unrecognized SID %d", sid);
1280 rc = -EINVAL;
1281 goto out;
1282 }
1283 rc = context_to_string(NULL, policydb, context, scontext, scontext_len);
1284 out:
1285 return rc;
1286
1287 }
1288
1289 /*
1290 * Return a SID associated with the security context that
1291 * has the string representation specified by `scontext'.
1292 */
sepol_context_to_sid(sepol_const_security_context_t scontext,size_t scontext_len,sepol_security_id_t * sid)1293 int sepol_context_to_sid(sepol_const_security_context_t scontext,
1294 size_t scontext_len, sepol_security_id_t * sid)
1295 {
1296
1297 context_struct_t *context = NULL;
1298
1299 /* First, create the context */
1300 if (context_from_string(NULL, policydb, &context,
1301 scontext, scontext_len) < 0)
1302 goto err;
1303
1304 /* Obtain the new sid */
1305 if (sid && (sepol_sidtab_context_to_sid(sidtab, context, sid) < 0))
1306 goto err;
1307
1308 context_destroy(context);
1309 free(context);
1310 return STATUS_SUCCESS;
1311
1312 err:
1313 if (context) {
1314 context_destroy(context);
1315 free(context);
1316 }
1317 ERR(NULL, "could not convert %s to sid", scontext);
1318 return STATUS_ERR;
1319 }
1320
compute_sid_handle_invalid_context(context_struct_t * scontext,context_struct_t * tcontext,sepol_security_class_t tclass,context_struct_t * newcontext)1321 static inline int compute_sid_handle_invalid_context(context_struct_t *
1322 scontext,
1323 context_struct_t *
1324 tcontext,
1325 sepol_security_class_t
1326 tclass,
1327 context_struct_t *
1328 newcontext)
1329 {
1330 if (selinux_enforcing) {
1331 return -EACCES;
1332 } else {
1333 sepol_security_context_t s, t, n;
1334 size_t slen, tlen, nlen;
1335
1336 context_to_string(NULL, policydb, scontext, &s, &slen);
1337 context_to_string(NULL, policydb, tcontext, &t, &tlen);
1338 context_to_string(NULL, policydb, newcontext, &n, &nlen);
1339 ERR(NULL, "invalid context %s for "
1340 "scontext=%s tcontext=%s tclass=%s",
1341 n, s, t, policydb->p_class_val_to_name[tclass - 1]);
1342 free(s);
1343 free(t);
1344 free(n);
1345 return 0;
1346 }
1347 }
1348
sepol_compute_sid(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,uint32_t specified,sepol_security_id_t * out_sid)1349 static int sepol_compute_sid(sepol_security_id_t ssid,
1350 sepol_security_id_t tsid,
1351 sepol_security_class_t tclass,
1352 uint32_t specified, sepol_security_id_t * out_sid)
1353 {
1354 struct class_datum *cladatum = NULL;
1355 context_struct_t *scontext = 0, *tcontext = 0, newcontext;
1356 struct role_trans *roletr = 0;
1357 avtab_key_t avkey;
1358 avtab_datum_t *avdatum;
1359 avtab_ptr_t node;
1360 int rc = 0;
1361
1362 scontext = sepol_sidtab_search(sidtab, ssid);
1363 if (!scontext) {
1364 ERR(NULL, "unrecognized SID %d", ssid);
1365 return -EINVAL;
1366 }
1367 tcontext = sepol_sidtab_search(sidtab, tsid);
1368 if (!tcontext) {
1369 ERR(NULL, "unrecognized SID %d", tsid);
1370 return -EINVAL;
1371 }
1372
1373 if (tclass && tclass <= policydb->p_classes.nprim)
1374 cladatum = policydb->class_val_to_struct[tclass - 1];
1375
1376 context_init(&newcontext);
1377
1378 /* Set the user identity. */
1379 switch (specified) {
1380 case AVTAB_TRANSITION:
1381 case AVTAB_CHANGE:
1382 if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
1383 newcontext.user = tcontext->user;
1384 } else {
1385 /* notice this gets both DEFAULT_SOURCE and unset */
1386 /* Use the process user identity. */
1387 newcontext.user = scontext->user;
1388 }
1389 break;
1390 case AVTAB_MEMBER:
1391 /* Use the related object owner. */
1392 newcontext.user = tcontext->user;
1393 break;
1394 }
1395
1396 /* Set the role to default values. */
1397 if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
1398 newcontext.role = scontext->role;
1399 } else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
1400 newcontext.role = tcontext->role;
1401 } else {
1402 if (tclass == policydb->process_class)
1403 newcontext.role = scontext->role;
1404 else
1405 newcontext.role = OBJECT_R_VAL;
1406 }
1407
1408 /* Set the type to default values. */
1409 if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
1410 newcontext.type = scontext->type;
1411 } else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
1412 newcontext.type = tcontext->type;
1413 } else {
1414 if (tclass == policydb->process_class) {
1415 /* Use the type of process. */
1416 newcontext.type = scontext->type;
1417 } else {
1418 /* Use the type of the related object. */
1419 newcontext.type = tcontext->type;
1420 }
1421 }
1422
1423 /* Look for a type transition/member/change rule. */
1424 avkey.source_type = scontext->type;
1425 avkey.target_type = tcontext->type;
1426 avkey.target_class = tclass;
1427 avkey.specified = specified;
1428 avdatum = avtab_search(&policydb->te_avtab, &avkey);
1429
1430 /* If no permanent rule, also check for enabled conditional rules */
1431 if (!avdatum) {
1432 node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
1433 for (; node != NULL;
1434 node = avtab_search_node_next(node, specified)) {
1435 if (node->key.specified & AVTAB_ENABLED) {
1436 avdatum = &node->datum;
1437 break;
1438 }
1439 }
1440 }
1441
1442 if (avdatum) {
1443 /* Use the type from the type transition/member/change rule. */
1444 newcontext.type = avdatum->data;
1445 }
1446
1447 /* Check for class-specific changes. */
1448 if (specified & AVTAB_TRANSITION) {
1449 /* Look for a role transition rule. */
1450 for (roletr = policydb->role_tr; roletr;
1451 roletr = roletr->next) {
1452 if (roletr->role == scontext->role &&
1453 roletr->type == tcontext->type &&
1454 roletr->tclass == tclass) {
1455 /* Use the role transition rule. */
1456 newcontext.role = roletr->new_role;
1457 break;
1458 }
1459 }
1460 }
1461
1462 /* Set the MLS attributes.
1463 This is done last because it may allocate memory. */
1464 rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
1465 &newcontext);
1466 if (rc)
1467 goto out;
1468
1469 /* Check the validity of the context. */
1470 if (!policydb_context_isvalid(policydb, &newcontext)) {
1471 rc = compute_sid_handle_invalid_context(scontext,
1472 tcontext,
1473 tclass, &newcontext);
1474 if (rc)
1475 goto out;
1476 }
1477 /* Obtain the sid for the context. */
1478 rc = sepol_sidtab_context_to_sid(sidtab, &newcontext, out_sid);
1479 out:
1480 context_destroy(&newcontext);
1481 return rc;
1482 }
1483
1484 /*
1485 * Compute a SID to use for labeling a new object in the
1486 * class `tclass' based on a SID pair.
1487 */
sepol_transition_sid(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,sepol_security_id_t * out_sid)1488 int sepol_transition_sid(sepol_security_id_t ssid,
1489 sepol_security_id_t tsid,
1490 sepol_security_class_t tclass,
1491 sepol_security_id_t * out_sid)
1492 {
1493 return sepol_compute_sid(ssid, tsid, tclass, AVTAB_TRANSITION, out_sid);
1494 }
1495
1496 /*
1497 * Compute a SID to use when selecting a member of a
1498 * polyinstantiated object of class `tclass' based on
1499 * a SID pair.
1500 */
sepol_member_sid(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,sepol_security_id_t * out_sid)1501 int sepol_member_sid(sepol_security_id_t ssid,
1502 sepol_security_id_t tsid,
1503 sepol_security_class_t tclass,
1504 sepol_security_id_t * out_sid)
1505 {
1506 return sepol_compute_sid(ssid, tsid, tclass, AVTAB_MEMBER, out_sid);
1507 }
1508
1509 /*
1510 * Compute a SID to use for relabeling an object in the
1511 * class `tclass' based on a SID pair.
1512 */
sepol_change_sid(sepol_security_id_t ssid,sepol_security_id_t tsid,sepol_security_class_t tclass,sepol_security_id_t * out_sid)1513 int sepol_change_sid(sepol_security_id_t ssid,
1514 sepol_security_id_t tsid,
1515 sepol_security_class_t tclass,
1516 sepol_security_id_t * out_sid)
1517 {
1518 return sepol_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, out_sid);
1519 }
1520
1521 /*
1522 * Verify that each permission that is defined under the
1523 * existing policy is still defined with the same value
1524 * in the new policy.
1525 */
validate_perm(hashtab_key_t key,hashtab_datum_t datum,void * p)1526 static int validate_perm(hashtab_key_t key, hashtab_datum_t datum, void *p)
1527 {
1528 hashtab_t h;
1529 perm_datum_t *perdatum, *perdatum2;
1530
1531 h = (hashtab_t) p;
1532 perdatum = (perm_datum_t *) datum;
1533
1534 perdatum2 = (perm_datum_t *) hashtab_search(h, key);
1535 if (!perdatum2) {
1536 ERR(NULL, "permission %s disappeared", key);
1537 return -1;
1538 }
1539 if (perdatum->s.value != perdatum2->s.value) {
1540 ERR(NULL, "the value of permissions %s changed", key);
1541 return -1;
1542 }
1543 return 0;
1544 }
1545
1546 /*
1547 * Verify that each class that is defined under the
1548 * existing policy is still defined with the same
1549 * attributes in the new policy.
1550 */
validate_class(hashtab_key_t key,hashtab_datum_t datum,void * p)1551 static int validate_class(hashtab_key_t key, hashtab_datum_t datum, void *p)
1552 {
1553 policydb_t *newp;
1554 class_datum_t *cladatum, *cladatum2;
1555
1556 newp = (policydb_t *) p;
1557 cladatum = (class_datum_t *) datum;
1558
1559 cladatum2 =
1560 (class_datum_t *) hashtab_search(newp->p_classes.table, key);
1561 if (!cladatum2) {
1562 ERR(NULL, "class %s disappeared", key);
1563 return -1;
1564 }
1565 if (cladatum->s.value != cladatum2->s.value) {
1566 ERR(NULL, "the value of class %s changed", key);
1567 return -1;
1568 }
1569 if ((cladatum->comdatum && !cladatum2->comdatum) ||
1570 (!cladatum->comdatum && cladatum2->comdatum)) {
1571 ERR(NULL, "the inherits clause for the access "
1572 "vector definition for class %s changed", key);
1573 return -1;
1574 }
1575 if (cladatum->comdatum) {
1576 if (hashtab_map
1577 (cladatum->comdatum->permissions.table, validate_perm,
1578 cladatum2->comdatum->permissions.table)) {
1579 ERR(NULL,
1580 " in the access vector definition "
1581 "for class %s", key);
1582 return -1;
1583 }
1584 }
1585 if (hashtab_map(cladatum->permissions.table, validate_perm,
1586 cladatum2->permissions.table)) {
1587 ERR(NULL, " in access vector definition for class %s", key);
1588 return -1;
1589 }
1590 return 0;
1591 }
1592
1593 /* Clone the SID into the new SID table. */
clone_sid(sepol_security_id_t sid,context_struct_t * context,void * arg)1594 static int clone_sid(sepol_security_id_t sid,
1595 context_struct_t * context, void *arg)
1596 {
1597 sidtab_t *s = arg;
1598
1599 return sepol_sidtab_insert(s, sid, context);
1600 }
1601
convert_context_handle_invalid_context(context_struct_t * context)1602 static inline int convert_context_handle_invalid_context(context_struct_t *
1603 context)
1604 {
1605 if (selinux_enforcing) {
1606 return -EINVAL;
1607 } else {
1608 sepol_security_context_t s;
1609 size_t len;
1610
1611 context_to_string(NULL, policydb, context, &s, &len);
1612 ERR(NULL, "context %s is invalid", s);
1613 free(s);
1614 return 0;
1615 }
1616 }
1617
1618 typedef struct {
1619 policydb_t *oldp;
1620 policydb_t *newp;
1621 } convert_context_args_t;
1622
1623 /*
1624 * Convert the values in the security context
1625 * structure `c' from the values specified
1626 * in the policy `p->oldp' to the values specified
1627 * in the policy `p->newp'. Verify that the
1628 * context is valid under the new policy.
1629 */
convert_context(sepol_security_id_t key,context_struct_t * c,void * p)1630 static int convert_context(sepol_security_id_t key __attribute__ ((unused)),
1631 context_struct_t * c, void *p)
1632 {
1633 convert_context_args_t *args;
1634 context_struct_t oldc;
1635 role_datum_t *role;
1636 type_datum_t *typdatum;
1637 user_datum_t *usrdatum;
1638 sepol_security_context_t s;
1639 size_t len;
1640 int rc = -EINVAL;
1641
1642 args = (convert_context_args_t *) p;
1643
1644 if (context_cpy(&oldc, c))
1645 return -ENOMEM;
1646
1647 /* Convert the user. */
1648 usrdatum = (user_datum_t *) hashtab_search(args->newp->p_users.table,
1649 args->oldp->
1650 p_user_val_to_name[c->user -
1651 1]);
1652
1653 if (!usrdatum) {
1654 goto bad;
1655 }
1656 c->user = usrdatum->s.value;
1657
1658 /* Convert the role. */
1659 role = (role_datum_t *) hashtab_search(args->newp->p_roles.table,
1660 args->oldp->
1661 p_role_val_to_name[c->role - 1]);
1662 if (!role) {
1663 goto bad;
1664 }
1665 c->role = role->s.value;
1666
1667 /* Convert the type. */
1668 typdatum = (type_datum_t *)
1669 hashtab_search(args->newp->p_types.table,
1670 args->oldp->p_type_val_to_name[c->type - 1]);
1671 if (!typdatum) {
1672 goto bad;
1673 }
1674 c->type = typdatum->s.value;
1675
1676 rc = mls_convert_context(args->oldp, args->newp, c);
1677 if (rc)
1678 goto bad;
1679
1680 /* Check the validity of the new context. */
1681 if (!policydb_context_isvalid(args->newp, c)) {
1682 rc = convert_context_handle_invalid_context(&oldc);
1683 if (rc)
1684 goto bad;
1685 }
1686
1687 context_destroy(&oldc);
1688 return 0;
1689
1690 bad:
1691 context_to_string(NULL, policydb, &oldc, &s, &len);
1692 context_destroy(&oldc);
1693 ERR(NULL, "invalidating context %s", s);
1694 free(s);
1695 return rc;
1696 }
1697
1698 /* Reading from a policy "file". */
next_entry(void * buf,struct policy_file * fp,size_t bytes)1699 int next_entry(void *buf, struct policy_file *fp, size_t bytes)
1700 {
1701 size_t nread;
1702
1703 switch (fp->type) {
1704 case PF_USE_STDIO:
1705 nread = fread(buf, bytes, 1, fp->fp);
1706
1707 if (nread != 1)
1708 return -1;
1709 break;
1710 case PF_USE_MEMORY:
1711 if (bytes > fp->len) {
1712 errno = EOVERFLOW;
1713 return -1;
1714 }
1715 memcpy(buf, fp->data, bytes);
1716 fp->data += bytes;
1717 fp->len -= bytes;
1718 break;
1719 default:
1720 errno = EINVAL;
1721 return -1;
1722 }
1723 return 0;
1724 }
1725
put_entry(const void * ptr,size_t size,size_t n,struct policy_file * fp)1726 size_t put_entry(const void *ptr, size_t size, size_t n,
1727 struct policy_file *fp)
1728 {
1729 size_t bytes;
1730
1731 if (__builtin_mul_overflow(size, n, &bytes))
1732 return 0;
1733
1734 switch (fp->type) {
1735 case PF_USE_STDIO:
1736 return fwrite(ptr, size, n, fp->fp);
1737 case PF_USE_MEMORY:
1738 if (bytes > fp->len) {
1739 errno = ENOSPC;
1740 return 0;
1741 }
1742
1743 memcpy(fp->data, ptr, bytes);
1744 fp->data += bytes;
1745 fp->len -= bytes;
1746 return n;
1747 case PF_LEN:
1748 fp->len += bytes;
1749 return n;
1750 default:
1751 return 0;
1752 }
1753 return 0;
1754 }
1755
1756 /*
1757 * Reads a string and null terminates it from the policy file.
1758 * This is a port of str_read from the SE Linux kernel code.
1759 *
1760 * It returns:
1761 * 0 - Success
1762 * -1 - Failure with errno set
1763 */
str_read(char ** strp,struct policy_file * fp,size_t len)1764 int str_read(char **strp, struct policy_file *fp, size_t len)
1765 {
1766 int rc;
1767 char *str;
1768
1769 if (zero_or_saturated(len) || exceeds_available_bytes(fp, len, sizeof(char))) {
1770 errno = EINVAL;
1771 return -1;
1772 }
1773
1774 str = malloc(len + 1);
1775 if (!str)
1776 return -1;
1777
1778 /* it's expected the caller should free the str */
1779 *strp = str;
1780
1781 /* next_entry sets errno */
1782 rc = next_entry(str, fp, len);
1783 if (rc)
1784 return rc;
1785
1786 str[len] = '\0';
1787 return 0;
1788 }
1789
1790 /*
1791 * Read a new set of configuration data from
1792 * a policy database binary representation file.
1793 *
1794 * Verify that each class that is defined under the
1795 * existing policy is still defined with the same
1796 * attributes in the new policy.
1797 *
1798 * Convert the context structures in the SID table to the
1799 * new representation and verify that all entries
1800 * in the SID table are valid under the new policy.
1801 *
1802 * Change the active policy database to use the new
1803 * configuration data.
1804 *
1805 * Reset the access vector cache.
1806 */
sepol_load_policy(void * data,size_t len)1807 int sepol_load_policy(void *data, size_t len)
1808 {
1809 policydb_t oldpolicydb, newpolicydb;
1810 sidtab_t oldsidtab, newsidtab;
1811 convert_context_args_t args;
1812 int rc = 0;
1813 struct policy_file file, *fp;
1814
1815 policy_file_init(&file);
1816 file.type = PF_USE_MEMORY;
1817 file.data = data;
1818 file.len = len;
1819 fp = &file;
1820
1821 if (policydb_init(&newpolicydb))
1822 return -ENOMEM;
1823
1824 if (policydb_read(&newpolicydb, fp, 1)) {
1825 policydb_destroy(&mypolicydb);
1826 return -EINVAL;
1827 }
1828
1829 sepol_sidtab_init(&newsidtab);
1830
1831 /* Verify that the existing classes did not change. */
1832 if (hashtab_map
1833 (policydb->p_classes.table, validate_class, &newpolicydb)) {
1834 ERR(NULL, "the definition of an existing class changed");
1835 rc = -EINVAL;
1836 goto err;
1837 }
1838
1839 /* Clone the SID table. */
1840 sepol_sidtab_shutdown(sidtab);
1841 if (sepol_sidtab_map(sidtab, clone_sid, &newsidtab)) {
1842 rc = -ENOMEM;
1843 goto err;
1844 }
1845
1846 /* Convert the internal representations of contexts
1847 in the new SID table and remove invalid SIDs. */
1848 args.oldp = policydb;
1849 args.newp = &newpolicydb;
1850 sepol_sidtab_map_remove_on_error(&newsidtab, convert_context, &args);
1851
1852 /* Save the old policydb and SID table to free later. */
1853 memcpy(&oldpolicydb, policydb, sizeof *policydb);
1854 sepol_sidtab_set(&oldsidtab, sidtab);
1855
1856 /* Install the new policydb and SID table. */
1857 memcpy(policydb, &newpolicydb, sizeof *policydb);
1858 sepol_sidtab_set(sidtab, &newsidtab);
1859
1860 /* Free the old policydb and SID table. */
1861 policydb_destroy(&oldpolicydb);
1862 sepol_sidtab_destroy(&oldsidtab);
1863
1864 return 0;
1865
1866 err:
1867 sepol_sidtab_destroy(&newsidtab);
1868 policydb_destroy(&newpolicydb);
1869 return rc;
1870
1871 }
1872
1873 /*
1874 * Return the SIDs to use for an unlabeled file system
1875 * that is being mounted from the device with the
1876 * the kdevname `name'. The `fs_sid' SID is returned for
1877 * the file system and the `file_sid' SID is returned
1878 * for all files within that file system.
1879 */
sepol_fs_sid(char * name,sepol_security_id_t * fs_sid,sepol_security_id_t * file_sid)1880 int sepol_fs_sid(char *name,
1881 sepol_security_id_t * fs_sid,
1882 sepol_security_id_t * file_sid)
1883 {
1884 int rc = 0;
1885 ocontext_t *c;
1886
1887 c = policydb->ocontexts[OCON_FS];
1888 while (c) {
1889 if (strcmp(c->u.name, name) == 0)
1890 break;
1891 c = c->next;
1892 }
1893
1894 if (c) {
1895 if (!c->sid[0] || !c->sid[1]) {
1896 rc = sepol_sidtab_context_to_sid(sidtab,
1897 &c->context[0],
1898 &c->sid[0]);
1899 if (rc)
1900 goto out;
1901 rc = sepol_sidtab_context_to_sid(sidtab,
1902 &c->context[1],
1903 &c->sid[1]);
1904 if (rc)
1905 goto out;
1906 }
1907 *fs_sid = c->sid[0];
1908 *file_sid = c->sid[1];
1909 } else {
1910 *fs_sid = SECINITSID_FS;
1911 *file_sid = SECINITSID_FILE;
1912 }
1913
1914 out:
1915 return rc;
1916 }
1917
1918 /*
1919 * Return the SID of the ibpkey specified by
1920 * `subnet prefix', and `pkey number'.
1921 */
sepol_ibpkey_sid(uint64_t subnet_prefix,uint16_t pkey,sepol_security_id_t * out_sid)1922 int sepol_ibpkey_sid(uint64_t subnet_prefix,
1923 uint16_t pkey, sepol_security_id_t *out_sid)
1924 {
1925 ocontext_t *c;
1926 int rc = 0;
1927
1928 c = policydb->ocontexts[OCON_IBPKEY];
1929 while (c) {
1930 if (c->u.ibpkey.low_pkey <= pkey &&
1931 c->u.ibpkey.high_pkey >= pkey &&
1932 subnet_prefix == c->u.ibpkey.subnet_prefix)
1933 break;
1934 c = c->next;
1935 }
1936
1937 if (c) {
1938 if (!c->sid[0]) {
1939 rc = sepol_sidtab_context_to_sid(sidtab,
1940 &c->context[0],
1941 &c->sid[0]);
1942 if (rc)
1943 goto out;
1944 }
1945 *out_sid = c->sid[0];
1946 } else {
1947 *out_sid = SECINITSID_UNLABELED;
1948 }
1949
1950 out:
1951 return rc;
1952 }
1953
1954 /*
1955 * Return the SID of the subnet management interface specified by
1956 * `device name', and `port'.
1957 */
sepol_ibendport_sid(char * dev_name,uint8_t port,sepol_security_id_t * out_sid)1958 int sepol_ibendport_sid(char *dev_name,
1959 uint8_t port,
1960 sepol_security_id_t *out_sid)
1961 {
1962 ocontext_t *c;
1963 int rc = 0;
1964
1965 c = policydb->ocontexts[OCON_IBENDPORT];
1966 while (c) {
1967 if (c->u.ibendport.port == port &&
1968 !strcmp(dev_name, c->u.ibendport.dev_name))
1969 break;
1970 c = c->next;
1971 }
1972
1973 if (c) {
1974 if (!c->sid[0]) {
1975 rc = sepol_sidtab_context_to_sid(sidtab,
1976 &c->context[0],
1977 &c->sid[0]);
1978 if (rc)
1979 goto out;
1980 }
1981 *out_sid = c->sid[0];
1982 } else {
1983 *out_sid = SECINITSID_UNLABELED;
1984 }
1985
1986 out:
1987 return rc;
1988 }
1989
1990
1991 /*
1992 * Return the SID of the port specified by
1993 * `domain', `type', `protocol', and `port'.
1994 */
sepol_port_sid(uint16_t domain,uint16_t type,uint8_t protocol,uint16_t port,sepol_security_id_t * out_sid)1995 int sepol_port_sid(uint16_t domain __attribute__ ((unused)),
1996 uint16_t type __attribute__ ((unused)),
1997 uint8_t protocol,
1998 uint16_t port, sepol_security_id_t * out_sid)
1999 {
2000 ocontext_t *c;
2001 int rc = 0;
2002
2003 c = policydb->ocontexts[OCON_PORT];
2004 while (c) {
2005 if (c->u.port.protocol == protocol &&
2006 c->u.port.low_port <= port && c->u.port.high_port >= port)
2007 break;
2008 c = c->next;
2009 }
2010
2011 if (c) {
2012 if (!c->sid[0]) {
2013 rc = sepol_sidtab_context_to_sid(sidtab,
2014 &c->context[0],
2015 &c->sid[0]);
2016 if (rc)
2017 goto out;
2018 }
2019 *out_sid = c->sid[0];
2020 } else {
2021 *out_sid = SECINITSID_PORT;
2022 }
2023
2024 out:
2025 return rc;
2026 }
2027
2028 /*
2029 * Return the SIDs to use for a network interface
2030 * with the name `name'. The `if_sid' SID is returned for
2031 * the interface and the `msg_sid' SID is returned as
2032 * the default SID for messages received on the
2033 * interface.
2034 */
sepol_netif_sid(char * name,sepol_security_id_t * if_sid,sepol_security_id_t * msg_sid)2035 int sepol_netif_sid(char *name,
2036 sepol_security_id_t * if_sid,
2037 sepol_security_id_t * msg_sid)
2038 {
2039 int rc = 0;
2040 ocontext_t *c;
2041
2042 c = policydb->ocontexts[OCON_NETIF];
2043 while (c) {
2044 if (strcmp(name, c->u.name) == 0)
2045 break;
2046 c = c->next;
2047 }
2048
2049 if (c) {
2050 if (!c->sid[0] || !c->sid[1]) {
2051 rc = sepol_sidtab_context_to_sid(sidtab,
2052 &c->context[0],
2053 &c->sid[0]);
2054 if (rc)
2055 goto out;
2056 rc = sepol_sidtab_context_to_sid(sidtab,
2057 &c->context[1],
2058 &c->sid[1]);
2059 if (rc)
2060 goto out;
2061 }
2062 *if_sid = c->sid[0];
2063 *msg_sid = c->sid[1];
2064 } else {
2065 *if_sid = SECINITSID_NETIF;
2066 *msg_sid = SECINITSID_NETMSG;
2067 }
2068
2069 out:
2070 return rc;
2071 }
2072
match_ipv6_addrmask(uint32_t * input,uint32_t * addr,uint32_t * mask)2073 static int match_ipv6_addrmask(uint32_t * input, uint32_t * addr,
2074 uint32_t * mask)
2075 {
2076 int i, fail = 0;
2077
2078 for (i = 0; i < 4; i++)
2079 if (addr[i] != (input[i] & mask[i])) {
2080 fail = 1;
2081 break;
2082 }
2083
2084 return !fail;
2085 }
2086
2087 /*
2088 * Return the SID of the node specified by the address
2089 * `addrp' where `addrlen' is the length of the address
2090 * in bytes and `domain' is the communications domain or
2091 * address family in which the address should be interpreted.
2092 */
sepol_node_sid(uint16_t domain,void * addrp,size_t addrlen,sepol_security_id_t * out_sid)2093 int sepol_node_sid(uint16_t domain,
2094 void *addrp,
2095 size_t addrlen, sepol_security_id_t * out_sid)
2096 {
2097 int rc = 0;
2098 ocontext_t *c;
2099
2100 switch (domain) {
2101 case AF_INET:{
2102 uint32_t addr;
2103
2104 if (addrlen != sizeof(uint32_t)) {
2105 rc = -EINVAL;
2106 goto out;
2107 }
2108
2109 addr = *((uint32_t *) addrp);
2110
2111 c = policydb->ocontexts[OCON_NODE];
2112 while (c) {
2113 if (c->u.node.addr == (addr & c->u.node.mask))
2114 break;
2115 c = c->next;
2116 }
2117 break;
2118 }
2119
2120 case AF_INET6:
2121 if (addrlen != sizeof(uint64_t) * 2) {
2122 rc = -EINVAL;
2123 goto out;
2124 }
2125
2126 c = policydb->ocontexts[OCON_NODE6];
2127 while (c) {
2128 if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2129 c->u.node6.mask))
2130 break;
2131 c = c->next;
2132 }
2133 break;
2134
2135 default:
2136 *out_sid = SECINITSID_NODE;
2137 goto out;
2138 }
2139
2140 if (c) {
2141 if (!c->sid[0]) {
2142 rc = sepol_sidtab_context_to_sid(sidtab,
2143 &c->context[0],
2144 &c->sid[0]);
2145 if (rc)
2146 goto out;
2147 }
2148 *out_sid = c->sid[0];
2149 } else {
2150 *out_sid = SECINITSID_NODE;
2151 }
2152
2153 out:
2154 return rc;
2155 }
2156
2157 /*
2158 * Generate the set of SIDs for legal security contexts
2159 * for a given user that can be reached by `fromsid'.
2160 * Set `*sids' to point to a dynamically allocated
2161 * array containing the set of SIDs. Set `*nel' to the
2162 * number of elements in the array.
2163 */
2164 #define SIDS_NEL 25
2165
sepol_get_user_sids(sepol_security_id_t fromsid,char * username,sepol_security_id_t ** sids,uint32_t * nel)2166 int sepol_get_user_sids(sepol_security_id_t fromsid,
2167 char *username,
2168 sepol_security_id_t ** sids, uint32_t * nel)
2169 {
2170 context_struct_t *fromcon, usercon;
2171 sepol_security_id_t *mysids, *mysids2, sid;
2172 uint32_t mynel = 0, maxnel = SIDS_NEL;
2173 user_datum_t *user;
2174 role_datum_t *role;
2175 struct sepol_av_decision avd;
2176 int rc = 0;
2177 unsigned int i, j, reason;
2178 ebitmap_node_t *rnode, *tnode;
2179
2180 fromcon = sepol_sidtab_search(sidtab, fromsid);
2181 if (!fromcon) {
2182 rc = -EINVAL;
2183 goto out;
2184 }
2185
2186 user = (user_datum_t *) hashtab_search(policydb->p_users.table,
2187 username);
2188 if (!user) {
2189 rc = -EINVAL;
2190 goto out;
2191 }
2192 usercon.user = user->s.value;
2193
2194 mysids = calloc(maxnel, sizeof(sepol_security_id_t));
2195 if (!mysids) {
2196 rc = -ENOMEM;
2197 goto out;
2198 }
2199
2200 ebitmap_for_each_positive_bit(&user->roles.roles, rnode, i) {
2201 role = policydb->role_val_to_struct[i];
2202 usercon.role = i + 1;
2203 ebitmap_for_each_positive_bit(&role->types.types, tnode, j) {
2204 usercon.type = j + 1;
2205 if (usercon.type == fromcon->type)
2206 continue;
2207
2208 if (mls_setup_user_range
2209 (fromcon, user, &usercon, policydb->mls))
2210 continue;
2211
2212 rc = context_struct_compute_av(fromcon, &usercon,
2213 policydb->process_class,
2214 policydb->process_trans,
2215 &avd, &reason, NULL, 0);
2216 if (rc || !(avd.allowed & policydb->process_trans))
2217 continue;
2218 rc = sepol_sidtab_context_to_sid(sidtab, &usercon,
2219 &sid);
2220 if (rc) {
2221 free(mysids);
2222 goto out;
2223 }
2224 if (mynel < maxnel) {
2225 mysids[mynel++] = sid;
2226 } else {
2227 maxnel += SIDS_NEL;
2228 mysids2 = calloc(maxnel, sizeof(sepol_security_id_t));
2229 if (!mysids2) {
2230 rc = -ENOMEM;
2231 free(mysids);
2232 goto out;
2233 }
2234 memcpy(mysids2, mysids,
2235 mynel * sizeof(sepol_security_id_t));
2236 free(mysids);
2237 mysids = mysids2;
2238 mysids[mynel++] = sid;
2239 }
2240 }
2241 }
2242
2243 *sids = mysids;
2244 *nel = mynel;
2245
2246 out:
2247 return rc;
2248 }
2249
2250 /*
2251 * Return the SID to use for a file in a filesystem
2252 * that cannot support a persistent label mapping or use another
2253 * fixed labeling behavior like transition SIDs or task SIDs.
2254 */
sepol_genfs_sid(const char * fstype,const char * path,sepol_security_class_t sclass,sepol_security_id_t * sid)2255 int sepol_genfs_sid(const char *fstype,
2256 const char *path,
2257 sepol_security_class_t sclass,
2258 sepol_security_id_t * sid)
2259 {
2260 size_t len;
2261 genfs_t *genfs;
2262 ocontext_t *c;
2263 int rc = 0, cmp = 0;
2264
2265 for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2266 cmp = strcmp(fstype, genfs->fstype);
2267 if (cmp <= 0)
2268 break;
2269 }
2270
2271 if (!genfs || cmp) {
2272 *sid = SECINITSID_UNLABELED;
2273 rc = -ENOENT;
2274 goto out;
2275 }
2276
2277 for (c = genfs->head; c; c = c->next) {
2278 len = strlen(c->u.name);
2279 if ((!c->v.sclass || sclass == c->v.sclass) &&
2280 (strncmp(c->u.name, path, len) == 0))
2281 break;
2282 }
2283
2284 if (!c) {
2285 *sid = SECINITSID_UNLABELED;
2286 rc = -ENOENT;
2287 goto out;
2288 }
2289
2290 if (!c->sid[0]) {
2291 rc = sepol_sidtab_context_to_sid(sidtab,
2292 &c->context[0], &c->sid[0]);
2293 if (rc)
2294 goto out;
2295 }
2296
2297 *sid = c->sid[0];
2298 out:
2299 return rc;
2300 }
2301
sepol_fs_use(const char * fstype,unsigned int * behavior,sepol_security_id_t * sid)2302 int sepol_fs_use(const char *fstype,
2303 unsigned int *behavior, sepol_security_id_t * sid)
2304 {
2305 int rc = 0;
2306 ocontext_t *c;
2307
2308 c = policydb->ocontexts[OCON_FSUSE];
2309 while (c) {
2310 if (strcmp(fstype, c->u.name) == 0)
2311 break;
2312 c = c->next;
2313 }
2314
2315 if (c) {
2316 *behavior = c->v.behavior;
2317 if (!c->sid[0]) {
2318 rc = sepol_sidtab_context_to_sid(sidtab,
2319 &c->context[0],
2320 &c->sid[0]);
2321 if (rc)
2322 goto out;
2323 }
2324 *sid = c->sid[0];
2325 } else {
2326 rc = sepol_genfs_sid(fstype, "/", policydb->dir_class, sid);
2327 if (rc) {
2328 *behavior = SECURITY_FS_USE_NONE;
2329 rc = 0;
2330 } else {
2331 *behavior = SECURITY_FS_USE_GENFS;
2332 }
2333 }
2334
2335 out:
2336 return rc;
2337 }
2338
2339 /* FLASK */
2340