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]);
157 void cond_policydb_destroy(struct policydb *p)
159 kfree(p->bool_val_to_struct);
160 avtab_destroy(&p->te_cond_avtab);
161 cond_list_destroy(p);
164 int cond_init_bool_indexes(struct policydb *p)
166 kfree(p->bool_val_to_struct);
167 p->bool_val_to_struct = kmalloc_array(p->p_bools.nprim,
168 sizeof(*p->bool_val_to_struct),
170 if (!p->bool_val_to_struct)
175 int cond_destroy_bool(void *key, void *datum, void *p)
182 int cond_index_bool(void *key, void *datum, void *datap)
185 struct cond_bool_datum *booldatum;
190 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
193 p->sym_val_to_name[SYM_BOOLS][booldatum->value - 1] = key;
194 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
199 static int bool_isvalid(struct cond_bool_datum *b)
201 if (!(b->state == 0 || b->state == 1))
206 int cond_read_bool(struct policydb *p, struct symtab *s, void *fp)
209 struct cond_bool_datum *booldatum;
214 booldatum = kzalloc(sizeof(*booldatum), GFP_KERNEL);
218 rc = next_entry(buf, fp, sizeof(buf));
222 booldatum->value = le32_to_cpu(buf[0]);
223 booldatum->state = le32_to_cpu(buf[1]);
226 if (!bool_isvalid(booldatum))
229 len = le32_to_cpu(buf[2]);
230 if (((len == 0) || (len == (u32)-1)))
234 key = kmalloc(len + 1, GFP_KERNEL);
237 rc = next_entry(key, fp, len);
241 rc = symtab_insert(s, key, booldatum);
247 cond_destroy_bool(key, booldatum, NULL);
251 struct cond_insertf_data {
253 struct avtab_node **dst;
254 struct cond_av_list *other;
257 static int cond_insertf(struct avtab *a, const struct avtab_key *k,
258 const struct avtab_datum *d, void *ptr)
260 struct cond_insertf_data *data = ptr;
261 struct policydb *p = data->p;
262 struct cond_av_list *other = data->other;
263 struct avtab_node *node_ptr;
268 * For type rules we have to make certain there aren't any
269 * conflicting rules by searching the te_avtab and the
272 if (k->specified & AVTAB_TYPE) {
273 if (avtab_search(&p->te_avtab, k)) {
274 pr_err("SELinux: type rule already exists outside of a conditional.\n");
278 * If we are reading the false list other will be a pointer to
279 * the true list. We can have duplicate entries if there is only
280 * 1 other entry and it is in our true list.
282 * If we are reading the true list (other == NULL) there shouldn't
283 * be any other entries.
286 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
288 if (avtab_search_node_next(node_ptr, k->specified)) {
289 pr_err("SELinux: too many conflicting type rules.\n");
293 for (i = 0; i < other->len; i++) {
294 if (other->nodes[i] == node_ptr) {
300 pr_err("SELinux: conflicting type rules.\n");
305 if (avtab_search(&p->te_cond_avtab, k)) {
306 pr_err("SELinux: conflicting type rules when adding type rule for true.\n");
312 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
314 pr_err("SELinux: could not insert rule.\n");
318 *data->dst = node_ptr;
322 static int cond_read_av_list(struct policydb *p, void *fp,
323 struct cond_av_list *list,
324 struct cond_av_list *other)
329 struct cond_insertf_data data;
331 rc = next_entry(buf, fp, sizeof(u32));
335 len = le32_to_cpu(buf[0]);
339 list->nodes = kcalloc(len, sizeof(*list->nodes), GFP_KERNEL);
345 for (i = 0; i < len; i++) {
346 data.dst = &list->nodes[i];
347 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
360 static int expr_node_isvalid(struct policydb *p, struct cond_expr_node *expr)
362 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
363 pr_err("SELinux: conditional expressions uses unknown operator.\n");
367 if (expr->bool > p->p_bools.nprim) {
368 pr_err("SELinux: conditional expressions uses unknown bool.\n");
374 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
380 rc = next_entry(buf, fp, sizeof(u32) * 2);
384 node->cur_state = le32_to_cpu(buf[0]);
387 len = le32_to_cpu(buf[1]);
388 node->expr.nodes = kcalloc(len, sizeof(*node->expr.nodes), GFP_KERNEL);
389 if (!node->expr.nodes)
392 node->expr.len = len;
394 for (i = 0; i < len; i++) {
395 struct cond_expr_node *expr = &node->expr.nodes[i];
397 rc = next_entry(buf, fp, sizeof(u32) * 2);
401 expr->expr_type = le32_to_cpu(buf[0]);
402 expr->bool = le32_to_cpu(buf[1]);
404 if (!expr_node_isvalid(p, expr))
408 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
411 return cond_read_av_list(p, fp, &node->false_list, &node->true_list);
414 int cond_read_list(struct policydb *p, void *fp)
420 rc = next_entry(buf, fp, sizeof(buf));
424 len = le32_to_cpu(buf[0]);
426 p->cond_list = kcalloc(len, sizeof(*p->cond_list), GFP_KERNEL);
430 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
434 p->cond_list_len = len;
436 for (i = 0; i < len; i++) {
437 rc = cond_read_node(p, &p->cond_list[i], fp);
443 cond_list_destroy(p);
448 int cond_write_bool(void *vkey, void *datum, void *ptr)
451 struct cond_bool_datum *booldatum = datum;
452 struct policy_data *pd = ptr;
459 buf[0] = cpu_to_le32(booldatum->value);
460 buf[1] = cpu_to_le32(booldatum->state);
461 buf[2] = cpu_to_le32(len);
462 rc = put_entry(buf, sizeof(u32), 3, fp);
465 rc = put_entry(key, 1, len, fp);
472 * cond_write_cond_av_list doesn't write out the av_list nodes.
473 * Instead it writes out the key/value pairs from the avtab. This
474 * is necessary because there is no way to uniquely identifying rules
475 * in the avtab so it is not possible to associate individual rules
476 * in the avtab with a conditional without saving them as part of
477 * the conditional. This means that the avtab with the conditional
478 * rules will not be saved but will be rebuilt on policy load.
480 static int cond_write_av_list(struct policydb *p,
481 struct cond_av_list *list, struct policy_file *fp)
487 buf[0] = cpu_to_le32(list->len);
488 rc = put_entry(buf, sizeof(u32), 1, fp);
492 for (i = 0; i < list->len; i++) {
493 rc = avtab_write_item(p, list->nodes[i], fp);
501 static int cond_write_node(struct policydb *p, struct cond_node *node,
502 struct policy_file *fp)
508 buf[0] = cpu_to_le32(node->cur_state);
509 rc = put_entry(buf, sizeof(u32), 1, fp);
513 buf[0] = cpu_to_le32(node->expr.len);
514 rc = put_entry(buf, sizeof(u32), 1, fp);
518 for (i = 0; i < node->expr.len; i++) {
519 buf[0] = cpu_to_le32(node->expr.nodes[i].expr_type);
520 buf[1] = cpu_to_le32(node->expr.nodes[i].bool);
521 rc = put_entry(buf, sizeof(u32), 2, fp);
526 rc = cond_write_av_list(p, &node->true_list, fp);
529 rc = cond_write_av_list(p, &node->false_list, fp);
536 int cond_write_list(struct policydb *p, void *fp)
542 buf[0] = cpu_to_le32(p->cond_list_len);
543 rc = put_entry(buf, sizeof(u32), 1, fp);
547 for (i = 0; i < p->cond_list_len; i++) {
548 rc = cond_write_node(p, &p->cond_list[i], fp);
556 void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
557 struct extended_perms_decision *xpermd)
559 struct avtab_node *node;
561 if (!ctab || !key || !xpermd)
564 for (node = avtab_search_node(ctab, key); node;
565 node = avtab_search_node_next(node, key->specified)) {
566 if (node->key.specified & AVTAB_ENABLED)
567 services_compute_xperms_decision(xpermd, node);
572 /* Determine whether additional permissions are granted by the conditional
573 * av table, and if so, add them to the result
575 void cond_compute_av(struct avtab *ctab, struct avtab_key *key,
576 struct av_decision *avd, struct extended_perms *xperms)
578 struct avtab_node *node;
580 if (!ctab || !key || !avd)
583 for (node = avtab_search_node(ctab, key); node;
584 node = avtab_search_node_next(node, key->specified)) {
585 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
586 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
587 avd->allowed |= node->datum.u.data;
588 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
589 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
590 /* Since a '0' in an auditdeny mask represents a
591 * permission we do NOT want to audit (dontaudit), we use
592 * the '&' operand to ensure that all '0's in the mask
593 * are retained (much unlike the allow and auditallow cases).
595 avd->auditdeny &= node->datum.u.data;
596 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
597 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
598 avd->auditallow |= node->datum.u.data;
599 if (xperms && (node->key.specified & AVTAB_ENABLED) &&
600 (node->key.specified & AVTAB_XPERMS))
601 services_compute_xperms_drivers(xperms, node);
605 static int cond_dup_av_list(struct cond_av_list *new,
606 struct cond_av_list *orig,
611 memset(new, 0, sizeof(*new));
613 new->nodes = kcalloc(orig->len, sizeof(*new->nodes), GFP_KERNEL);
617 for (i = 0; i < orig->len; i++) {
618 new->nodes[i] = avtab_insert_nonunique(avtab,
619 &orig->nodes[i]->key,
620 &orig->nodes[i]->datum);
629 static int duplicate_policydb_cond_list(struct policydb *newp,
630 struct policydb *origp)
635 rc = avtab_alloc_dup(&newp->te_cond_avtab, &origp->te_cond_avtab);
639 newp->cond_list_len = 0;
640 newp->cond_list = kcalloc(origp->cond_list_len,
641 sizeof(*newp->cond_list),
643 if (!newp->cond_list)
646 for (i = 0; i < origp->cond_list_len; i++) {
647 struct cond_node *newn = &newp->cond_list[i];
648 struct cond_node *orign = &origp->cond_list[i];
650 newp->cond_list_len++;
652 newn->cur_state = orign->cur_state;
653 newn->expr.nodes = kmemdup(orign->expr.nodes,
654 orign->expr.len * sizeof(*orign->expr.nodes),
656 if (!newn->expr.nodes)
659 newn->expr.len = orign->expr.len;
661 rc = cond_dup_av_list(&newn->true_list, &orign->true_list,
662 &newp->te_cond_avtab);
666 rc = cond_dup_av_list(&newn->false_list, &orign->false_list,
667 &newp->te_cond_avtab);
675 avtab_destroy(&newp->te_cond_avtab);
676 cond_list_destroy(newp);
680 static int cond_bools_destroy(void *key, void *datum, void *args)
682 /* key was not copied so no need to free here */
687 static int cond_bools_copy(struct hashtab_node *new, struct hashtab_node *orig, void *args)
689 struct cond_bool_datum *datum;
691 datum = kmemdup(orig->datum, sizeof(struct cond_bool_datum),
696 new->key = orig->key; /* No need to copy, never modified */
701 static int cond_bools_index(void *key, void *datum, void *args)
703 struct cond_bool_datum *booldatum, **cond_bool_array;
706 cond_bool_array = args;
707 cond_bool_array[booldatum->value - 1] = booldatum;
712 static int duplicate_policydb_bools(struct policydb *newdb,
713 struct policydb *orig)
715 struct cond_bool_datum **cond_bool_array;
718 cond_bool_array = kmalloc_array(orig->p_bools.nprim,
719 sizeof(*orig->bool_val_to_struct),
721 if (!cond_bool_array)
724 rc = hashtab_duplicate(&newdb->p_bools.table, &orig->p_bools.table,
725 cond_bools_copy, cond_bools_destroy, NULL);
727 kfree(cond_bool_array);
731 hashtab_map(&newdb->p_bools.table, cond_bools_index, cond_bool_array);
732 newdb->bool_val_to_struct = cond_bool_array;
734 newdb->p_bools.nprim = orig->p_bools.nprim;
739 void cond_policydb_destroy_dup(struct policydb *p)
741 hashtab_map(&p->p_bools.table, cond_bools_destroy, NULL);
742 hashtab_destroy(&p->p_bools.table);
743 cond_policydb_destroy(p);
746 int cond_policydb_dup(struct policydb *new, struct policydb *orig)
748 cond_policydb_init(new);
750 if (duplicate_policydb_bools(new, orig))
753 if (duplicate_policydb_cond_list(new, orig)) {
754 cond_policydb_destroy_dup(new);