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-rw-r--r--security/selinux/ss/services.c138
1 files changed, 137 insertions, 1 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 33ae1020091e..408820486af0 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -17,9 +17,13 @@
*
* Added support for NetLabel
*
+ * Updated: Chad Sellers <csellers@tresys.com>
+ *
+ * Added validation of kernel classes and permissions
+ *
* Copyright (C) 2006 Hewlett-Packard Development Company, L.P.
* Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
- * Copyright (C) 2003 - 2004 Tresys Technology, LLC
+ * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC
* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
* 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
@@ -53,6 +57,11 @@
extern void selnl_notify_policyload(u32 seqno);
unsigned int policydb_loaded_version;
+/*
+ * This is declared in avc.c
+ */
+extern const struct selinux_class_perm selinux_class_perm;
+
static DEFINE_RWLOCK(policy_rwlock);
#define POLICY_RDLOCK read_lock(&policy_rwlock)
#define POLICY_WRLOCK write_lock_irq(&policy_rwlock)
@@ -1018,6 +1027,115 @@ int security_change_sid(u32 ssid,
return security_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, out_sid);
}
+/*
+ * Verify that each kernel class that is defined in the
+ * policy is correct
+ */
+static int validate_classes(struct policydb *p)
+{
+ int i, j;
+ struct class_datum *cladatum;
+ struct perm_datum *perdatum;
+ u32 nprim, tmp, common_pts_len, perm_val, pol_val;
+ u16 class_val;
+ const struct selinux_class_perm *kdefs = &selinux_class_perm;
+ const char *def_class, *def_perm, *pol_class;
+ struct symtab *perms;
+
+ for (i = 1; i < kdefs->cts_len; i++) {
+ def_class = kdefs->class_to_string[i];
+ if (i > p->p_classes.nprim) {
+ printk(KERN_INFO
+ "security: class %s not defined in policy\n",
+ def_class);
+ continue;
+ }
+ pol_class = p->p_class_val_to_name[i-1];
+ if (strcmp(pol_class, def_class)) {
+ printk(KERN_ERR
+ "security: class %d is incorrect, found %s but should be %s\n",
+ i, pol_class, def_class);
+ return -EINVAL;
+ }
+ }
+ for (i = 0; i < kdefs->av_pts_len; i++) {
+ class_val = kdefs->av_perm_to_string[i].tclass;
+ perm_val = kdefs->av_perm_to_string[i].value;
+ def_perm = kdefs->av_perm_to_string[i].name;
+ if (class_val > p->p_classes.nprim)
+ continue;
+ pol_class = p->p_class_val_to_name[class_val-1];
+ cladatum = hashtab_search(p->p_classes.table, pol_class);
+ BUG_ON(!cladatum);
+ perms = &cladatum->permissions;
+ nprim = 1 << (perms->nprim - 1);
+ if (perm_val > nprim) {
+ printk(KERN_INFO
+ "security: permission %s in class %s not defined in policy\n",
+ def_perm, pol_class);
+ continue;
+ }
+ perdatum = hashtab_search(perms->table, def_perm);
+ if (perdatum == NULL) {
+ printk(KERN_ERR
+ "security: permission %s in class %s not found in policy\n",
+ def_perm, pol_class);
+ return -EINVAL;
+ }
+ pol_val = 1 << (perdatum->value - 1);
+ if (pol_val != perm_val) {
+ printk(KERN_ERR
+ "security: permission %s in class %s has incorrect value\n",
+ def_perm, pol_class);
+ return -EINVAL;
+ }
+ }
+ for (i = 0; i < kdefs->av_inherit_len; i++) {
+ class_val = kdefs->av_inherit[i].tclass;
+ if (class_val > p->p_classes.nprim)
+ continue;
+ pol_class = p->p_class_val_to_name[class_val-1];
+ cladatum = hashtab_search(p->p_classes.table, pol_class);
+ BUG_ON(!cladatum);
+ if (!cladatum->comdatum) {
+ printk(KERN_ERR
+ "security: class %s should have an inherits clause but does not\n",
+ pol_class);
+ return -EINVAL;
+ }
+ tmp = kdefs->av_inherit[i].common_base;
+ common_pts_len = 0;
+ while (!(tmp & 0x01)) {
+ common_pts_len++;
+ tmp >>= 1;
+ }
+ perms = &cladatum->comdatum->permissions;
+ for (j = 0; j < common_pts_len; j++) {
+ def_perm = kdefs->av_inherit[i].common_pts[j];
+ if (j >= perms->nprim) {
+ printk(KERN_INFO
+ "security: permission %s in class %s not defined in policy\n",
+ def_perm, pol_class);
+ continue;
+ }
+ perdatum = hashtab_search(perms->table, def_perm);
+ if (perdatum == NULL) {
+ printk(KERN_ERR
+ "security: permission %s in class %s not found in policy\n",
+ def_perm, pol_class);
+ return -EINVAL;
+ }
+ if (perdatum->value != j + 1) {
+ printk(KERN_ERR
+ "security: permission %s in class %s has incorrect value\n",
+ def_perm, pol_class);
+ return -EINVAL;
+ }
+ }
+ }
+ return 0;
+}
+
/* Clone the SID into the new SID table. */
static int clone_sid(u32 sid,
struct context *context,
@@ -1160,6 +1278,16 @@ int security_load_policy(void *data, size_t len)
avtab_cache_destroy();
return -EINVAL;
}
+ /* Verify that the kernel defined classes are correct. */
+ if (validate_classes(&policydb)) {
+ printk(KERN_ERR
+ "security: the definition of a class is incorrect\n");
+ LOAD_UNLOCK;
+ sidtab_destroy(&sidtab);
+ policydb_destroy(&policydb);
+ avtab_cache_destroy();
+ return -EINVAL;
+ }
policydb_loaded_version = policydb.policyvers;
ss_initialized = 1;
seqno = ++latest_granting;
@@ -1182,6 +1310,14 @@ int security_load_policy(void *data, size_t len)
sidtab_init(&newsidtab);
+ /* Verify that the kernel defined classes are correct. */
+ if (validate_classes(&newpolicydb)) {
+ printk(KERN_ERR
+ "security: the definition of a class is incorrect\n");
+ rc = -EINVAL;
+ goto err;
+ }
+
/* Clone the SID table. */
sidtab_shutdown(&sidtab);
if (sidtab_map(&sidtab, clone_sid, &newsidtab)) {

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