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