1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Authors: Karl MacMillan <kmacmillan@tresys.com>
3 * Frank Mayer <mayerf@tresys.com>
5 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
8 #include <linux/kernel.h>
9 #include <linux/errno.h>
10 #include <linux/string.h>
11 #include <linux/spinlock.h>
12 #include <linux/slab.h>
15 #include "conditional.h"
19 * cond_evaluate_expr evaluates a conditional expr
20 * in reverse polish notation. It returns true (1), false (0),
21 * or undefined (-1). Undefined occurs when the expression
22 * exceeds the stack depth of COND_EXPR_MAXDEPTH.
24 static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
27 int s[COND_EXPR_MAXDEPTH];
33 for (i = 0; i < expr->len; i++) {
34 struct cond_expr_node *node = &expr->nodes[i];
36 switch (node->expr_type) {
38 if (sp == (COND_EXPR_MAXDEPTH - 1))
41 s[sp] = p->bool_val_to_struct[node->bool - 1]->state;
70 s[sp] = (s[sp] == s[sp + 1]);
76 s[sp] = (s[sp] != s[sp + 1]);
86 * evaluate_cond_node evaluates the conditional stored in
87 * a struct cond_node and if the result is different than the
88 * current state of the node it sets the rules in the true/false
89 * list appropriately. If the result of the expression is undefined
90 * all of the rules are disabled for safety.
92 static void evaluate_cond_node(struct policydb *p, struct cond_node *node)
94 struct avtab_node *avnode;
98 new_state = cond_evaluate_expr(p, &node->expr);
99 if (new_state != node->cur_state) {
100 node->cur_state = new_state;
102 pr_err("SELinux: expression result was undefined - disabling all rules.\n");
103 /* turn the rules on or off */
104 for (i = 0; i < node->true_list.len; i++) {
105 avnode = node->true_list.nodes[i];
107 avnode->key.specified &= ~AVTAB_ENABLED;
109 avnode->key.specified |= AVTAB_ENABLED;
112 for (i = 0; i < node->false_list.len; i++) {
113 avnode = node->false_list.nodes[i];
116 avnode->key.specified &= ~AVTAB_ENABLED;
118 avnode->key.specified |= AVTAB_ENABLED;
123 void evaluate_cond_nodes(struct policydb *p)
127 for (i = 0; i < p->cond_list_len; i++)
128 evaluate_cond_node(p, &p->cond_list[i]);
131 void cond_policydb_init(struct policydb *p)
133 p->bool_val_to_struct = NULL;
135 p->cond_list_len = 0;
137 avtab_init(&p->te_cond_avtab);
140 static void cond_node_destroy(struct cond_node *node)
142 kfree(node->expr.nodes);
143 /* the avtab_ptr_t nodes are destroyed by the avtab */
144 kfree(node->true_list.nodes);
145 kfree(node->false_list.nodes);
148 static void cond_list_destroy(struct policydb *p)
152 for (i = 0; i < p->cond_list_len; i++)
153 cond_node_destroy(&p->cond_list[i]);
156 p->cond_list_len = 0;
159 void cond_policydb_destroy(struct policydb *p)
161 kfree(p->bool_val_to_struct);
162 avtab_destroy(&p->te_cond_avtab);
163 cond_list_destroy(p);
166 int cond_init_bool_indexes(struct policydb *p)
168 kfree(p->bool_val_to_struct);
169 p->bool_val_to_struct = kmalloc_array(p->p_bools.nprim,
170 sizeof(*p->bool_val_to_struct),
172 if (!p->bool_val_to_struct)
177 int cond_destroy_bool(void *key, void *datum, void *p)
184 int cond_index_bool(void *key, void *datum, void *datap)
187 struct cond_bool_datum *booldatum;
192 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
195 p->sym_val_to_name[SYM_BOOLS][booldatum->value - 1] = key;
196 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
201 static int bool_isvalid(struct cond_bool_datum *b)
203 if (!(b->state == 0 || b->state == 1))
208 int cond_read_bool(struct policydb *p, struct symtab *s, void *fp)
211 struct cond_bool_datum *booldatum;
216 booldatum = kzalloc(sizeof(*booldatum), GFP_KERNEL);
220 rc = next_entry(buf, fp, sizeof(buf));
224 booldatum->value = le32_to_cpu(buf[0]);
225 booldatum->state = le32_to_cpu(buf[1]);
228 if (!bool_isvalid(booldatum))
231 len = le32_to_cpu(buf[2]);
232 if (((len == 0) || (len == (u32)-1)))
236 key = kmalloc(len + 1, GFP_KERNEL);
239 rc = next_entry(key, fp, len);
243 rc = symtab_insert(s, key, booldatum);
249 cond_destroy_bool(key, booldatum, NULL);
253 struct cond_insertf_data {
255 struct avtab_node **dst;
256 struct cond_av_list *other;
259 static int cond_insertf(struct avtab *a, const struct avtab_key *k,
260 const struct avtab_datum *d, void *ptr)
262 struct cond_insertf_data *data = ptr;
263 struct policydb *p = data->p;
264 struct cond_av_list *other = data->other;
265 struct avtab_node *node_ptr;
270 * For type rules we have to make certain there aren't any
271 * conflicting rules by searching the te_avtab and the
274 if (k->specified & AVTAB_TYPE) {
275 if (avtab_search(&p->te_avtab, k)) {
276 pr_err("SELinux: type rule already exists outside of a conditional.\n");
280 * If we are reading the false list other will be a pointer to
281 * the true list. We can have duplicate entries if there is only
282 * 1 other entry and it is in our true list.
284 * If we are reading the true list (other == NULL) there shouldn't
285 * be any other entries.
288 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
290 if (avtab_search_node_next(node_ptr, k->specified)) {
291 pr_err("SELinux: too many conflicting type rules.\n");
295 for (i = 0; i < other->len; i++) {
296 if (other->nodes[i] == node_ptr) {
302 pr_err("SELinux: conflicting type rules.\n");
307 if (avtab_search(&p->te_cond_avtab, k)) {
308 pr_err("SELinux: conflicting type rules when adding type rule for true.\n");
314 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
316 pr_err("SELinux: could not insert rule.\n");
320 *data->dst = node_ptr;
324 static int cond_read_av_list(struct policydb *p, void *fp,
325 struct cond_av_list *list,
326 struct cond_av_list *other)
331 struct cond_insertf_data data;
333 rc = next_entry(buf, fp, sizeof(u32));
337 len = le32_to_cpu(buf[0]);
341 list->nodes = kcalloc(len, sizeof(*list->nodes), GFP_KERNEL);
347 for (i = 0; i < len; i++) {
348 data.dst = &list->nodes[i];
349 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
362 static int expr_node_isvalid(struct policydb *p, struct cond_expr_node *expr)
364 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
365 pr_err("SELinux: conditional expressions uses unknown operator.\n");
369 if (expr->bool > p->p_bools.nprim) {
370 pr_err("SELinux: conditional expressions uses unknown bool.\n");
376 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
382 rc = next_entry(buf, fp, sizeof(u32) * 2);
386 node->cur_state = le32_to_cpu(buf[0]);
389 len = le32_to_cpu(buf[1]);
390 node->expr.nodes = kcalloc(len, sizeof(*node->expr.nodes), GFP_KERNEL);
391 if (!node->expr.nodes)
394 node->expr.len = len;
396 for (i = 0; i < len; i++) {
397 struct cond_expr_node *expr = &node->expr.nodes[i];
399 rc = next_entry(buf, fp, sizeof(u32) * 2);
403 expr->expr_type = le32_to_cpu(buf[0]);
404 expr->bool = le32_to_cpu(buf[1]);
406 if (!expr_node_isvalid(p, expr))
410 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
413 return cond_read_av_list(p, fp, &node->false_list, &node->true_list);
416 int cond_read_list(struct policydb *p, void *fp)
422 rc = next_entry(buf, fp, sizeof(buf));
426 len = le32_to_cpu(buf[0]);
428 p->cond_list = kcalloc(len, sizeof(*p->cond_list), GFP_KERNEL);
432 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
436 p->cond_list_len = len;
438 for (i = 0; i < len; i++) {
439 rc = cond_read_node(p, &p->cond_list[i], fp);
445 cond_list_destroy(p);
449 int cond_write_bool(void *vkey, void *datum, void *ptr)
452 struct cond_bool_datum *booldatum = datum;
453 struct policy_data *pd = ptr;
460 buf[0] = cpu_to_le32(booldatum->value);
461 buf[1] = cpu_to_le32(booldatum->state);
462 buf[2] = cpu_to_le32(len);
463 rc = put_entry(buf, sizeof(u32), 3, fp);
466 rc = put_entry(key, 1, len, fp);
473 * cond_write_cond_av_list doesn't write out the av_list nodes.
474 * Instead it writes out the key/value pairs from the avtab. This
475 * is necessary because there is no way to uniquely identifying rules
476 * in the avtab so it is not possible to associate individual rules
477 * in the avtab with a conditional without saving them as part of
478 * the conditional. This means that the avtab with the conditional
479 * rules will not be saved but will be rebuilt on policy load.
481 static int cond_write_av_list(struct policydb *p,
482 struct cond_av_list *list, struct policy_file *fp)
488 buf[0] = cpu_to_le32(list->len);
489 rc = put_entry(buf, sizeof(u32), 1, fp);
493 for (i = 0; i < list->len; i++) {
494 rc = avtab_write_item(p, list->nodes[i], fp);
502 static int cond_write_node(struct policydb *p, struct cond_node *node,
503 struct policy_file *fp)
509 buf[0] = cpu_to_le32(node->cur_state);
510 rc = put_entry(buf, sizeof(u32), 1, fp);
514 buf[0] = cpu_to_le32(node->expr.len);
515 rc = put_entry(buf, sizeof(u32), 1, fp);
519 for (i = 0; i < node->expr.len; i++) {
520 buf[0] = cpu_to_le32(node->expr.nodes[i].expr_type);
521 buf[1] = cpu_to_le32(node->expr.nodes[i].bool);
522 rc = put_entry(buf, sizeof(u32), 2, fp);
527 rc = cond_write_av_list(p, &node->true_list, fp);
530 rc = cond_write_av_list(p, &node->false_list, fp);
537 int cond_write_list(struct policydb *p, void *fp)
543 buf[0] = cpu_to_le32(p->cond_list_len);
544 rc = put_entry(buf, sizeof(u32), 1, fp);
548 for (i = 0; i < p->cond_list_len; i++) {
549 rc = cond_write_node(p, &p->cond_list[i], fp);
557 void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
558 struct extended_perms_decision *xpermd)
560 struct avtab_node *node;
562 if (!ctab || !key || !xpermd)
565 for (node = avtab_search_node(ctab, key); node;
566 node = avtab_search_node_next(node, key->specified)) {
567 if (node->key.specified & AVTAB_ENABLED)
568 services_compute_xperms_decision(xpermd, node);
571 /* Determine whether additional permissions are granted by the conditional
572 * av table, and if so, add them to the result
574 void cond_compute_av(struct avtab *ctab, struct avtab_key *key,
575 struct av_decision *avd, struct extended_perms *xperms)
577 struct avtab_node *node;
579 if (!ctab || !key || !avd)
582 for (node = avtab_search_node(ctab, key); node;
583 node = avtab_search_node_next(node, key->specified)) {
584 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
585 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
586 avd->allowed |= node->datum.u.data;
587 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
588 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
589 /* Since a '0' in an auditdeny mask represents a
590 * permission we do NOT want to audit (dontaudit), we use
591 * the '&' operand to ensure that all '0's in the mask
592 * are retained (much unlike the allow and auditallow cases).
594 avd->auditdeny &= node->datum.u.data;
595 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
596 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
597 avd->auditallow |= node->datum.u.data;
598 if (xperms && (node->key.specified & AVTAB_ENABLED) &&
599 (node->key.specified & AVTAB_XPERMS))
600 services_compute_xperms_drivers(xperms, node);
604 static int cond_dup_av_list(struct cond_av_list *new,
605 struct cond_av_list *orig,
610 memset(new, 0, sizeof(*new));
612 new->nodes = kcalloc(orig->len, sizeof(*new->nodes), GFP_KERNEL);
616 for (i = 0; i < orig->len; i++) {
617 new->nodes[i] = avtab_insert_nonunique(avtab,
618 &orig->nodes[i]->key,
619 &orig->nodes[i]->datum);
628 static int duplicate_policydb_cond_list(struct policydb *newp,
629 struct policydb *origp)
634 rc = avtab_alloc_dup(&newp->te_cond_avtab, &origp->te_cond_avtab);
638 newp->cond_list_len = 0;
639 newp->cond_list = kcalloc(origp->cond_list_len,
640 sizeof(*newp->cond_list),
642 if (!newp->cond_list)
645 for (i = 0; i < origp->cond_list_len; i++) {
646 struct cond_node *newn = &newp->cond_list[i];
647 struct cond_node *orign = &origp->cond_list[i];
649 newp->cond_list_len++;
651 newn->cur_state = orign->cur_state;
652 newn->expr.nodes = kmemdup(orign->expr.nodes,
653 orign->expr.len * sizeof(*orign->expr.nodes),
655 if (!newn->expr.nodes)
658 newn->expr.len = orign->expr.len;
660 rc = cond_dup_av_list(&newn->true_list, &orign->true_list,
661 &newp->te_cond_avtab);
665 rc = cond_dup_av_list(&newn->false_list, &orign->false_list,
666 &newp->te_cond_avtab);
674 avtab_destroy(&newp->te_cond_avtab);
675 cond_list_destroy(newp);
679 static int cond_bools_destroy(void *key, void *datum, void *args)
681 /* key was not copied so no need to free here */
686 static int cond_bools_copy(struct hashtab_node *new, struct hashtab_node *orig, void *args)
688 struct cond_bool_datum *datum;
690 datum = kmemdup(orig->datum, sizeof(struct cond_bool_datum),
695 new->key = orig->key; /* No need to copy, never modified */
700 static int cond_bools_index(void *key, void *datum, void *args)
702 struct cond_bool_datum *booldatum, **cond_bool_array;
705 cond_bool_array = args;
706 cond_bool_array[booldatum->value - 1] = booldatum;
711 static int duplicate_policydb_bools(struct policydb *newdb,
712 struct policydb *orig)
714 struct cond_bool_datum **cond_bool_array;
717 cond_bool_array = kmalloc_array(orig->p_bools.nprim,
718 sizeof(*orig->bool_val_to_struct),
720 if (!cond_bool_array)
723 rc = hashtab_duplicate(&newdb->p_bools.table, &orig->p_bools.table,
724 cond_bools_copy, cond_bools_destroy, NULL);
726 kfree(cond_bool_array);
730 hashtab_map(&newdb->p_bools.table, cond_bools_index, cond_bool_array);
731 newdb->bool_val_to_struct = cond_bool_array;
733 newdb->p_bools.nprim = orig->p_bools.nprim;
738 void cond_policydb_destroy_dup(struct policydb *p)
740 hashtab_map(&p->p_bools.table, cond_bools_destroy, NULL);
741 hashtab_destroy(&p->p_bools.table);
742 cond_policydb_destroy(p);
745 int cond_policydb_dup(struct policydb *new, struct policydb *orig)
747 cond_policydb_init(new);
749 if (duplicate_policydb_bools(new, orig))
752 if (duplicate_policydb_cond_list(new, orig)) {
753 cond_policydb_destroy_dup(new);