1 /* SPDX-License-Identifier: GPL-2.0-only */
4 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
7 #include <linux/kernel.h>
8 #include <linux/errno.h>
9 #include <linux/string.h>
10 #include <linux/spinlock.h>
11 #include <linux/slab.h>
14 #include "conditional.h"
18 * cond_evaluate_expr evaluates a conditional expr
19 * in reverse polish notation. It returns true (1), false (0),
20 * or undefined (-1). Undefined occurs when the expression
21 * exceeds the stack depth of COND_EXPR_MAXDEPTH.
23 static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
26 int s[COND_EXPR_MAXDEPTH];
32 for (i = 0; i < expr->len; i++) {
33 struct cond_expr_node *node = &expr->nodes[i];
35 switch (node->expr_type) {
37 if (sp == (COND_EXPR_MAXDEPTH - 1))
40 s[sp] = p->bool_val_to_struct[node->boolean - 1]->state;
69 s[sp] = (s[sp] == s[sp + 1]);
75 s[sp] = (s[sp] != s[sp + 1]);
85 * evaluate_cond_node evaluates the conditional stored in
86 * a struct cond_node and if the result is different than the
87 * current state of the node it sets the rules in the true/false
88 * list appropriately. If the result of the expression is undefined
89 * all of the rules are disabled for safety.
91 static void evaluate_cond_node(struct policydb *p, struct cond_node *node)
93 struct avtab_node *avnode;
97 new_state = cond_evaluate_expr(p, &node->expr);
98 if (new_state != node->cur_state) {
99 node->cur_state = new_state;
101 pr_err("SELinux: expression result was undefined - disabling all rules.\n");
102 /* turn the rules on or off */
103 for (i = 0; i < node->true_list.len; i++) {
104 avnode = node->true_list.nodes[i];
106 avnode->key.specified &= ~AVTAB_ENABLED;
108 avnode->key.specified |= AVTAB_ENABLED;
111 for (i = 0; i < node->false_list.len; i++) {
112 avnode = node->false_list.nodes[i];
115 avnode->key.specified &= ~AVTAB_ENABLED;
117 avnode->key.specified |= AVTAB_ENABLED;
122 void evaluate_cond_nodes(struct policydb *p)
126 for (i = 0; i < p->cond_list_len; i++)
127 evaluate_cond_node(p, &p->cond_list[i]);
130 void cond_policydb_init(struct policydb *p)
132 p->bool_val_to_struct = NULL;
134 p->cond_list_len = 0;
136 avtab_init(&p->te_cond_avtab);
139 static void cond_node_destroy(struct cond_node *node)
141 kfree(node->expr.nodes);
142 /* the avtab_ptr_t nodes are destroyed by the avtab */
143 kfree(node->true_list.nodes);
144 kfree(node->false_list.nodes);
147 static void cond_list_destroy(struct policydb *p)
151 for (i = 0; i < p->cond_list_len; i++)
152 cond_node_destroy(&p->cond_list[i]);
155 p->cond_list_len = 0;
158 void cond_policydb_destroy(struct policydb *p)
160 kfree(p->bool_val_to_struct);
161 avtab_destroy(&p->te_cond_avtab);
162 cond_list_destroy(p);
165 int cond_init_bool_indexes(struct policydb *p)
167 kfree(p->bool_val_to_struct);
168 p->bool_val_to_struct = kmalloc_array(
169 p->p_bools.nprim, sizeof(*p->bool_val_to_struct), GFP_KERNEL);
170 if (!p->bool_val_to_struct)
173 avtab_hash_eval(&p->te_cond_avtab, "conditional_rules");
178 int cond_destroy_bool(void *key, void *datum, void *p)
185 int cond_index_bool(void *key, void *datum, void *datap)
188 struct cond_bool_datum *booldatum;
193 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
196 p->sym_val_to_name[SYM_BOOLS][booldatum->value - 1] = key;
197 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
202 static int bool_isvalid(struct cond_bool_datum *b)
204 if (!(b->state == 0 || b->state == 1))
209 int cond_read_bool(struct policydb *p, struct symtab *s, void *fp)
212 struct cond_bool_datum *booldatum;
217 booldatum = kzalloc(sizeof(*booldatum), GFP_KERNEL);
221 rc = next_entry(buf, fp, sizeof(buf));
225 booldatum->value = le32_to_cpu(buf[0]);
226 booldatum->state = le32_to_cpu(buf[1]);
229 if (!bool_isvalid(booldatum))
232 len = le32_to_cpu(buf[2]);
233 if (((len == 0) || (len == (u32)-1)))
237 key = kmalloc(len + 1, GFP_KERNEL);
240 rc = next_entry(key, fp, len);
244 rc = symtab_insert(s, key, booldatum);
250 cond_destroy_bool(key, booldatum, NULL);
254 struct cond_insertf_data {
256 struct avtab_node **dst;
257 struct cond_av_list *other;
260 static int cond_insertf(struct avtab *a, const struct avtab_key *k,
261 const struct avtab_datum *d, void *ptr)
263 struct cond_insertf_data *data = ptr;
264 struct policydb *p = data->p;
265 struct cond_av_list *other = data->other;
266 struct avtab_node *node_ptr;
271 * For type rules we have to make certain there aren't any
272 * conflicting rules by searching the te_avtab and the
275 if (k->specified & AVTAB_TYPE) {
276 if (avtab_search_node(&p->te_avtab, k)) {
277 pr_err("SELinux: type rule already exists outside of a conditional.\n");
281 * If we are reading the false list other will be a pointer to
282 * the true list. We can have duplicate entries if there is only
283 * 1 other entry and it is in our true list.
285 * If we are reading the true list (other == NULL) there shouldn't
286 * be any other entries.
289 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
291 if (avtab_search_node_next(node_ptr,
293 pr_err("SELinux: too many conflicting type rules.\n");
297 for (i = 0; i < other->len; i++) {
298 if (other->nodes[i] == node_ptr) {
304 pr_err("SELinux: conflicting type rules.\n");
309 if (avtab_search_node(&p->te_cond_avtab, k)) {
310 pr_err("SELinux: conflicting type rules when adding type rule for true.\n");
316 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
318 pr_err("SELinux: could not insert rule.\n");
322 *data->dst = node_ptr;
326 static int cond_read_av_list(struct policydb *p, void *fp,
327 struct cond_av_list *list,
328 struct cond_av_list *other)
333 struct cond_insertf_data data;
335 rc = next_entry(buf, fp, sizeof(u32));
339 len = le32_to_cpu(buf[0]);
343 list->nodes = kcalloc(len, sizeof(*list->nodes), GFP_KERNEL);
349 for (i = 0; i < len; i++) {
350 data.dst = &list->nodes[i];
351 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
364 static int expr_node_isvalid(struct policydb *p, struct cond_expr_node *expr)
366 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
367 pr_err("SELinux: conditional expressions uses unknown operator.\n");
371 if (expr->boolean > p->p_bools.nprim) {
372 pr_err("SELinux: conditional expressions uses unknown bool.\n");
378 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
384 rc = next_entry(buf, fp, sizeof(u32) * 2);
388 node->cur_state = le32_to_cpu(buf[0]);
391 len = le32_to_cpu(buf[1]);
392 node->expr.nodes = kcalloc(len, sizeof(*node->expr.nodes), GFP_KERNEL);
393 if (!node->expr.nodes)
396 node->expr.len = len;
398 for (i = 0; i < len; i++) {
399 struct cond_expr_node *expr = &node->expr.nodes[i];
401 rc = next_entry(buf, fp, sizeof(u32) * 2);
405 expr->expr_type = le32_to_cpu(buf[0]);
406 expr->boolean = le32_to_cpu(buf[1]);
408 if (!expr_node_isvalid(p, expr))
412 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
415 return cond_read_av_list(p, fp, &node->false_list, &node->true_list);
418 int cond_read_list(struct policydb *p, void *fp)
424 rc = next_entry(buf, fp, sizeof(buf));
428 len = le32_to_cpu(buf[0]);
430 p->cond_list = kcalloc(len, sizeof(*p->cond_list), GFP_KERNEL);
434 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
438 p->cond_list_len = len;
440 for (i = 0; i < len; i++) {
441 rc = cond_read_node(p, &p->cond_list[i], fp);
447 cond_list_destroy(p);
451 int cond_write_bool(void *vkey, void *datum, void *ptr)
454 struct cond_bool_datum *booldatum = datum;
455 struct policy_data *pd = ptr;
462 buf[0] = cpu_to_le32(booldatum->value);
463 buf[1] = cpu_to_le32(booldatum->state);
464 buf[2] = cpu_to_le32(len);
465 rc = put_entry(buf, sizeof(u32), 3, fp);
468 rc = put_entry(key, 1, len, fp);
475 * cond_write_cond_av_list doesn't write out the av_list nodes.
476 * Instead it writes out the key/value pairs from the avtab. This
477 * is necessary because there is no way to uniquely identifying rules
478 * in the avtab so it is not possible to associate individual rules
479 * in the avtab with a conditional without saving them as part of
480 * the conditional. This means that the avtab with the conditional
481 * rules will not be saved but will be rebuilt on policy load.
483 static int cond_write_av_list(struct policydb *p, struct cond_av_list *list,
484 struct policy_file *fp)
490 buf[0] = cpu_to_le32(list->len);
491 rc = put_entry(buf, sizeof(u32), 1, fp);
495 for (i = 0; i < list->len; i++) {
496 rc = avtab_write_item(p, list->nodes[i], fp);
504 static int cond_write_node(struct policydb *p, struct cond_node *node,
505 struct policy_file *fp)
511 buf[0] = cpu_to_le32(node->cur_state);
512 rc = put_entry(buf, sizeof(u32), 1, fp);
516 buf[0] = cpu_to_le32(node->expr.len);
517 rc = put_entry(buf, sizeof(u32), 1, fp);
521 for (i = 0; i < node->expr.len; i++) {
522 buf[0] = cpu_to_le32(node->expr.nodes[i].expr_type);
523 buf[1] = cpu_to_le32(node->expr.nodes[i].boolean);
524 rc = put_entry(buf, sizeof(u32), 2, fp);
529 rc = cond_write_av_list(p, &node->true_list, fp);
532 rc = cond_write_av_list(p, &node->false_list, fp);
539 int cond_write_list(struct policydb *p, void *fp)
545 buf[0] = cpu_to_le32(p->cond_list_len);
546 rc = put_entry(buf, sizeof(u32), 1, fp);
550 for (i = 0; i < p->cond_list_len; i++) {
551 rc = cond_write_node(p, &p->cond_list[i], fp);
559 void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
560 struct extended_perms_decision *xpermd)
562 struct avtab_node *node;
564 if (!ctab || !key || !xpermd)
567 for (node = avtab_search_node(ctab, key); node;
568 node = avtab_search_node_next(node, key->specified)) {
569 if (node->key.specified & AVTAB_ENABLED)
570 services_compute_xperms_decision(xpermd, node);
573 /* Determine whether additional permissions are granted by the conditional
574 * av table, and if so, add them to the result
576 void cond_compute_av(struct avtab *ctab, struct avtab_key *key,
577 struct av_decision *avd, struct extended_perms *xperms)
579 struct avtab_node *node;
581 if (!ctab || !key || !avd)
584 for (node = avtab_search_node(ctab, key); node;
585 node = avtab_search_node_next(node, key->specified)) {
586 if ((u16)(AVTAB_ALLOWED | AVTAB_ENABLED) ==
587 (node->key.specified & (AVTAB_ALLOWED | AVTAB_ENABLED)))
588 avd->allowed |= node->datum.u.data;
589 if ((u16)(AVTAB_AUDITDENY | AVTAB_ENABLED) ==
590 (node->key.specified & (AVTAB_AUDITDENY | AVTAB_ENABLED)))
591 /* Since a '0' in an auditdeny mask represents a
592 * permission we do NOT want to audit (dontaudit), we use
593 * the '&' operand to ensure that all '0's in the mask
594 * are retained (much unlike the allow and auditallow cases).
596 avd->auditdeny &= node->datum.u.data;
597 if ((u16)(AVTAB_AUDITALLOW | AVTAB_ENABLED) ==
598 (node->key.specified & (AVTAB_AUDITALLOW | AVTAB_ENABLED)))
599 avd->auditallow |= node->datum.u.data;
600 if (xperms && (node->key.specified & AVTAB_ENABLED) &&
601 (node->key.specified & AVTAB_XPERMS))
602 services_compute_xperms_drivers(xperms, node);
606 static int cond_dup_av_list(struct cond_av_list *new,
607 const struct cond_av_list *orig,
612 memset(new, 0, sizeof(*new));
614 new->nodes = kcalloc(orig->len, sizeof(*new->nodes), GFP_KERNEL);
618 for (i = 0; i < orig->len; i++) {
619 new->nodes[i] = avtab_insert_nonunique(
620 avtab, &orig->nodes[i]->key, &orig->nodes[i]->datum);
629 static int duplicate_policydb_cond_list(struct policydb *newp,
630 const 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), GFP_KERNEL);
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 const struct cond_node *orign = &origp->cond_list[i];
649 newp->cond_list_len++;
651 newn->cur_state = orign->cur_state;
653 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,
688 const struct hashtab_node *orig, void *args)
690 struct cond_bool_datum *datum;
692 datum = kmemdup(orig->datum, sizeof(struct cond_bool_datum),
697 new->key = orig->key; /* No need to copy, never modified */
702 static int cond_bools_index(void *key, void *datum, void *args)
704 struct cond_bool_datum *booldatum, **cond_bool_array;
707 cond_bool_array = args;
708 cond_bool_array[booldatum->value - 1] = booldatum;
713 static int duplicate_policydb_bools(struct policydb *newdb,
714 const struct policydb *orig)
716 struct cond_bool_datum **cond_bool_array;
719 cond_bool_array = kmalloc_array(orig->p_bools.nprim,
720 sizeof(*orig->bool_val_to_struct),
722 if (!cond_bool_array)
725 rc = hashtab_duplicate(&newdb->p_bools.table, &orig->p_bools.table,
726 cond_bools_copy, cond_bools_destroy, NULL);
728 kfree(cond_bool_array);
732 hashtab_map(&newdb->p_bools.table, cond_bools_index, cond_bool_array);
733 newdb->bool_val_to_struct = cond_bool_array;
735 newdb->p_bools.nprim = orig->p_bools.nprim;
740 void cond_policydb_destroy_dup(struct policydb *p)
742 hashtab_map(&p->p_bools.table, cond_bools_destroy, NULL);
743 hashtab_destroy(&p->p_bools.table);
744 cond_policydb_destroy(p);
747 int cond_policydb_dup(struct policydb *new, const struct policydb *orig)
749 cond_policydb_init(new);
751 if (duplicate_policydb_bools(new, orig))
754 if (duplicate_policydb_cond_list(new, orig)) {
755 cond_policydb_destroy_dup(new);