[PATCH] selinux: add hooks for key subsystem
Introduce SELinux hooks to support the access key retention subsystem
within the kernel. Incorporate new flask headers from a modified version
of the SELinux reference policy, with support for the new security class
representing retained keys. Extend the "key_alloc" security hook with a
task parameter representing the intended ownership context for the key
being allocated. Attach security information to root's default keyrings
within the SELinux initialization routine.
Has passed David's testsuite.
Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 54adc9d..524915d 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4252,6 +4252,57 @@
return size;
}
+#ifdef CONFIG_KEYS
+
+static int selinux_key_alloc(struct key *k, struct task_struct *tsk)
+{
+ struct task_security_struct *tsec = tsk->security;
+ struct key_security_struct *ksec;
+
+ ksec = kzalloc(sizeof(struct key_security_struct), GFP_KERNEL);
+ if (!ksec)
+ return -ENOMEM;
+
+ ksec->obj = k;
+ ksec->sid = tsec->sid;
+ k->security = ksec;
+
+ return 0;
+}
+
+static void selinux_key_free(struct key *k)
+{
+ struct key_security_struct *ksec = k->security;
+
+ k->security = NULL;
+ kfree(ksec);
+}
+
+static int selinux_key_permission(key_ref_t key_ref,
+ struct task_struct *ctx,
+ key_perm_t perm)
+{
+ struct key *key;
+ struct task_security_struct *tsec;
+ struct key_security_struct *ksec;
+
+ key = key_ref_to_ptr(key_ref);
+
+ tsec = ctx->security;
+ ksec = key->security;
+
+ /* if no specific permissions are requested, we skip the
+ permission check. No serious, additional covert channels
+ appear to be created. */
+ if (perm == 0)
+ return 0;
+
+ return avc_has_perm(tsec->sid, ksec->sid,
+ SECCLASS_KEY, perm, NULL);
+}
+
+#endif
+
static struct security_operations selinux_ops = {
.ptrace = selinux_ptrace,
.capget = selinux_capget,
@@ -4406,6 +4457,12 @@
.xfrm_state_delete_security = selinux_xfrm_state_delete,
.xfrm_policy_lookup = selinux_xfrm_policy_lookup,
#endif
+
+#ifdef CONFIG_KEYS
+ .key_alloc = selinux_key_alloc,
+ .key_free = selinux_key_free,
+ .key_permission = selinux_key_permission,
+#endif
};
static __init int selinux_init(void)
@@ -4441,6 +4498,13 @@
} else {
printk(KERN_INFO "SELinux: Starting in permissive mode\n");
}
+
+#ifdef CONFIG_KEYS
+ /* Add security information to initial keyrings */
+ security_key_alloc(&root_user_keyring, current);
+ security_key_alloc(&root_session_keyring, current);
+#endif
+
return 0;
}