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 000000000000..b53441184aca
--- /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;
+}