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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /security/selinux/ss/conditional.c
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Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'security/selinux/ss/conditional.c')
-rw-r--r--security/selinux/ss/conditional.c489
1 files changed, 489 insertions, 0 deletions
diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
new file mode 100644
index 00000000000..b53441184ac
--- /dev/null
+++ b/security/selinux/ss/conditional.c
@@ -0,0 +1,489 @@
+/* Authors: Karl MacMillan <kmacmillan@tresys.com>
+ * Frank Mayer <mayerf@tresys.com>
+ *
+ * Copyright (C) 2003 - 2004 Tresys Technology, LLC
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <asm/semaphore.h>
+#include <linux/slab.h>
+
+#include "security.h"
+#include "conditional.h"
+
+/*
+ * cond_evaluate_expr evaluates a conditional expr
+ * in reverse polish notation. It returns true (1), false (0),
+ * or undefined (-1). Undefined occurs when the expression
+ * exceeds the stack depth of COND_EXPR_MAXDEPTH.
+ */
+static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
+{
+
+ struct cond_expr *cur;
+ int s[COND_EXPR_MAXDEPTH];
+ int sp = -1;
+
+ for (cur = expr; cur != NULL; cur = cur->next) {
+ switch (cur->expr_type) {
+ case COND_BOOL:
+ if (sp == (COND_EXPR_MAXDEPTH - 1))
+ return -1;
+ sp++;
+ s[sp] = p->bool_val_to_struct[cur->bool - 1]->state;
+ break;
+ case COND_NOT:
+ if (sp < 0)
+ return -1;
+ s[sp] = !s[sp];
+ break;
+ case COND_OR:
+ if (sp < 1)
+ return -1;
+ sp--;
+ s[sp] |= s[sp + 1];
+ break;
+ case COND_AND:
+ if (sp < 1)
+ return -1;
+ sp--;
+ s[sp] &= s[sp + 1];
+ break;
+ case COND_XOR:
+ if (sp < 1)
+ return -1;
+ sp--;
+ s[sp] ^= s[sp + 1];
+ break;
+ case COND_EQ:
+ if (sp < 1)
+ return -1;
+ sp--;
+ s[sp] = (s[sp] == s[sp + 1]);
+ break;
+ case COND_NEQ:
+ if (sp < 1)
+ return -1;
+ sp--;
+ s[sp] = (s[sp] != s[sp + 1]);
+ break;
+ default:
+ return -1;
+ }
+ }
+ return s[0];
+}
+
+/*
+ * evaluate_cond_node evaluates the conditional stored in
+ * a struct cond_node and if the result is different than the
+ * current state of the node it sets the rules in the true/false
+ * list appropriately. If the result of the expression is undefined
+ * all of the rules are disabled for safety.
+ */
+int evaluate_cond_node(struct policydb *p, struct cond_node *node)
+{
+ int new_state;
+ struct cond_av_list* cur;
+
+ new_state = cond_evaluate_expr(p, node->expr);
+ if (new_state != node->cur_state) {
+ node->cur_state = new_state;
+ if (new_state == -1)
+ printk(KERN_ERR "security: expression result was undefined - disabling all rules.\n");
+ /* turn the rules on or off */
+ for (cur = node->true_list; cur != NULL; cur = cur->next) {
+ if (new_state <= 0) {
+ cur->node->datum.specified &= ~AVTAB_ENABLED;
+ } else {
+ cur->node->datum.specified |= AVTAB_ENABLED;
+ }
+ }
+
+ for (cur = node->false_list; cur != NULL; cur = cur->next) {
+ /* -1 or 1 */
+ if (new_state) {
+ cur->node->datum.specified &= ~AVTAB_ENABLED;
+ } else {
+ cur->node->datum.specified |= AVTAB_ENABLED;
+ }
+ }
+ }
+ return 0;
+}
+
+int cond_policydb_init(struct policydb *p)
+{
+ p->bool_val_to_struct = NULL;
+ p->cond_list = NULL;
+ if (avtab_init(&p->te_cond_avtab))
+ return -1;
+
+ return 0;
+}
+
+static void cond_av_list_destroy(struct cond_av_list *list)
+{
+ struct cond_av_list *cur, *next;
+ for (cur = list; cur != NULL; cur = next) {
+ next = cur->next;
+ /* the avtab_ptr_t node is destroy by the avtab */
+ kfree(cur);
+ }
+}
+
+static void cond_node_destroy(struct cond_node *node)
+{
+ struct cond_expr *cur_expr, *next_expr;
+
+ for (cur_expr = node->expr; cur_expr != NULL; cur_expr = next_expr) {
+ next_expr = cur_expr->next;
+ kfree(cur_expr);
+ }
+ cond_av_list_destroy(node->true_list);
+ cond_av_list_destroy(node->false_list);
+ kfree(node);
+}
+
+static void cond_list_destroy(struct cond_node *list)
+{
+ struct cond_node *next, *cur;
+
+ if (list == NULL)
+ return;
+
+ for (cur = list; cur != NULL; cur = next) {
+ next = cur->next;
+ cond_node_destroy(cur);
+ }
+}
+
+void cond_policydb_destroy(struct policydb *p)
+{
+ if (p->bool_val_to_struct != NULL)
+ kfree(p->bool_val_to_struct);
+ avtab_destroy(&p->te_cond_avtab);
+ cond_list_destroy(p->cond_list);
+}
+
+int cond_init_bool_indexes(struct policydb *p)
+{
+ if (p->bool_val_to_struct)
+ kfree(p->bool_val_to_struct);
+ p->bool_val_to_struct = (struct cond_bool_datum**)
+ kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum*), GFP_KERNEL);
+ if (!p->bool_val_to_struct)
+ return -1;
+ return 0;
+}
+
+int cond_destroy_bool(void *key, void *datum, void *p)
+{
+ if (key)
+ kfree(key);
+ kfree(datum);
+ return 0;
+}
+
+int cond_index_bool(void *key, void *datum, void *datap)
+{
+ struct policydb *p;
+ struct cond_bool_datum *booldatum;
+
+ booldatum = datum;
+ p = datap;
+
+ if (!booldatum->value || booldatum->value > p->p_bools.nprim)
+ return -EINVAL;
+
+ p->p_bool_val_to_name[booldatum->value - 1] = key;
+ p->bool_val_to_struct[booldatum->value -1] = booldatum;
+
+ return 0;
+}
+
+static int bool_isvalid(struct cond_bool_datum *b)
+{
+ if (!(b->state == 0 || b->state == 1))
+ return 0;
+ return 1;
+}
+
+int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
+{
+ char *key = NULL;
+ struct cond_bool_datum *booldatum;
+ u32 buf[3], len;
+ int rc;
+
+ booldatum = kmalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
+ if (!booldatum)
+ return -1;
+ memset(booldatum, 0, sizeof(struct cond_bool_datum));
+
+ rc = next_entry(buf, fp, sizeof buf);
+ if (rc < 0)
+ goto err;
+
+ booldatum->value = le32_to_cpu(buf[0]);
+ booldatum->state = le32_to_cpu(buf[1]);
+
+ if (!bool_isvalid(booldatum))
+ goto err;
+
+ len = le32_to_cpu(buf[2]);
+
+ key = kmalloc(len + 1, GFP_KERNEL);
+ if (!key)
+ goto err;
+ rc = next_entry(key, fp, len);
+ if (rc < 0)
+ goto err;
+ key[len] = 0;
+ if (hashtab_insert(h, key, booldatum))
+ goto err;
+
+ return 0;
+err:
+ cond_destroy_bool(key, booldatum, NULL);
+ return -1;
+}
+
+static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list,
+ struct cond_av_list *other)
+{
+ struct cond_av_list *list, *last = NULL, *cur;
+ struct avtab_key key;
+ struct avtab_datum datum;
+ struct avtab_node *node_ptr;
+ int rc;
+ u32 buf[1], i, len;
+ u8 found;
+
+ *ret_list = NULL;
+
+ len = 0;
+ rc = next_entry(buf, fp, sizeof buf);
+ if (rc < 0)
+ return -1;
+
+ len = le32_to_cpu(buf[0]);
+ if (len == 0) {
+ return 0;
+ }
+
+ for (i = 0; i < len; i++) {
+ if (avtab_read_item(fp, &datum, &key))
+ goto err;
+
+ /*
+ * For type rules we have to make certain there aren't any
+ * conflicting rules by searching the te_avtab and the
+ * cond_te_avtab.
+ */
+ if (datum.specified & AVTAB_TYPE) {
+ if (avtab_search(&p->te_avtab, &key, AVTAB_TYPE)) {
+ printk("security: type rule already exists outside of a conditional.");
+ goto err;
+ }
+ /*
+ * If we are reading the false list other will be a pointer to
+ * the true list. We can have duplicate entries if there is only
+ * 1 other entry and it is in our true list.
+ *
+ * If we are reading the true list (other == NULL) there shouldn't
+ * be any other entries.
+ */
+ if (other) {
+ node_ptr = avtab_search_node(&p->te_cond_avtab, &key, AVTAB_TYPE);
+ if (node_ptr) {
+ if (avtab_search_node_next(node_ptr, AVTAB_TYPE)) {
+ printk("security: too many conflicting type rules.");
+ goto err;
+ }
+ found = 0;
+ for (cur = other; cur != NULL; cur = cur->next) {
+ if (cur->node == node_ptr) {
+ found = 1;
+ break;
+ }
+ }
+ if (!found) {
+ printk("security: conflicting type rules.");
+ goto err;
+ }
+ }
+ } else {
+ if (avtab_search(&p->te_cond_avtab, &key, AVTAB_TYPE)) {
+ printk("security: conflicting type rules when adding type rule for true.");
+ goto err;
+ }
+ }
+ }
+ node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, &key, &datum);
+ if (!node_ptr) {
+ printk("security: could not insert rule.");
+ goto err;
+ }
+
+ list = kmalloc(sizeof(struct cond_av_list), GFP_KERNEL);
+ if (!list)
+ goto err;
+ memset(list, 0, sizeof(struct cond_av_list));
+
+ list->node = node_ptr;
+ if (i == 0)
+ *ret_list = list;
+ else
+ last->next = list;
+ last = list;
+
+ }
+
+ return 0;
+err:
+ cond_av_list_destroy(*ret_list);
+ *ret_list = NULL;
+ return -1;
+}
+
+static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
+{
+ if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
+ printk("security: conditional expressions uses unknown operator.\n");
+ return 0;
+ }
+
+ if (expr->bool > p->p_bools.nprim) {
+ printk("security: conditional expressions uses unknown bool.\n");
+ return 0;
+ }
+ return 1;
+}
+
+static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
+{
+ u32 buf[2], len, i;
+ int rc;
+ struct cond_expr *expr = NULL, *last = NULL;
+
+ rc = next_entry(buf, fp, sizeof(u32));
+ if (rc < 0)
+ return -1;
+
+ node->cur_state = le32_to_cpu(buf[0]);
+
+ len = 0;
+ rc = next_entry(buf, fp, sizeof(u32));
+ if (rc < 0)
+ return -1;
+
+ /* expr */
+ len = le32_to_cpu(buf[0]);
+
+ for (i = 0; i < len; i++ ) {
+ rc = next_entry(buf, fp, sizeof(u32) * 2);
+ if (rc < 0)
+ goto err;
+
+ expr = kmalloc(sizeof(struct cond_expr), GFP_KERNEL);
+ if (!expr) {
+ goto err;
+ }
+ memset(expr, 0, sizeof(struct cond_expr));
+
+ expr->expr_type = le32_to_cpu(buf[0]);
+ expr->bool = le32_to_cpu(buf[1]);
+
+ if (!expr_isvalid(p, expr)) {
+ kfree(expr);
+ goto err;
+ }
+
+ if (i == 0) {
+ node->expr = expr;
+ } else {
+ last->next = expr;
+ }
+ last = expr;
+ }
+
+ if (cond_read_av_list(p, fp, &node->true_list, NULL) != 0)
+ goto err;
+ if (cond_read_av_list(p, fp, &node->false_list, node->true_list) != 0)
+ goto err;
+ return 0;
+err:
+ cond_node_destroy(node);
+ return -1;
+}
+
+int cond_read_list(struct policydb *p, void *fp)
+{
+ struct cond_node *node, *last = NULL;
+ u32 buf[1], i, len;
+ int rc;
+
+ rc = next_entry(buf, fp, sizeof buf);
+ if (rc < 0)
+ return -1;
+
+ len = le32_to_cpu(buf[0]);
+
+ for (i = 0; i < len; i++) {
+ node = kmalloc(sizeof(struct cond_node), GFP_KERNEL);
+ if (!node)
+ goto err;
+ memset(node, 0, sizeof(struct cond_node));
+
+ if (cond_read_node(p, node, fp) != 0)
+ goto err;
+
+ if (i == 0) {
+ p->cond_list = node;
+ } else {
+ last->next = node;
+ }
+ last = node;
+ }
+ return 0;
+err:
+ cond_list_destroy(p->cond_list);
+ return -1;
+}
+
+/* Determine whether additional permissions are granted by the conditional
+ * av table, and if so, add them to the result
+ */
+void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
+{
+ struct avtab_node *node;
+
+ if(!ctab || !key || !avd)
+ return;
+
+ for(node = avtab_search_node(ctab, key, AVTAB_AV); node != NULL;
+ node = avtab_search_node_next(node, AVTAB_AV)) {
+ if ( (__u32) (AVTAB_ALLOWED|AVTAB_ENABLED) ==
+ (node->datum.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
+ avd->allowed |= avtab_allowed(&node->datum);
+ if ( (__u32) (AVTAB_AUDITDENY|AVTAB_ENABLED) ==
+ (node->datum.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
+ /* Since a '0' in an auditdeny mask represents a
+ * permission we do NOT want to audit (dontaudit), we use
+ * the '&' operand to ensure that all '0's in the mask
+ * are retained (much unlike the allow and auditallow cases).
+ */
+ avd->auditdeny &= avtab_auditdeny(&node->datum);
+ if ( (__u32) (AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
+ (node->datum.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
+ avd->auditallow |= avtab_auditallow(&node->datum);
+ }
+ return;
+}