[PATCH 1/4] device_cgroup: add "deny_all" in dev_cgroup structure

[Aristeu Rozanski <aris-moeOTchvdi7YtjvyW6yDsg@public.gmane.org>]

[-- Attachment #1: deny_all.patch --]
[-- Type: text/plain, Size: 1662 bytes --]

deny_all will determine if the default policy is to deny all device access
unless for the ones in the exception list.

This variable will be used in the next patches to convert device_cgroup
internally into a default policy + rules.

Signed-off-by: Aristeu Rozanski <aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

---
 security/device_cgroup.c |    5 +++++
 1 file changed, 5 insertions(+)

Index: github/security/device_cgroup.c
===================================================================
--- github.orig/security/device_cgroup.c	2012-07-24 17:15:58.277108951 -0400
+++ github/security/device_cgroup.c	2012-07-24 17:16:00.085156162 -0400
@@ -42,6 +42,7 @@
 struct dev_cgroup {
 	struct cgroup_subsys_state css;
 	struct list_head whitelist;
+	bool deny_all;
 };
 
 static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
@@ -178,12 +179,14 @@
 		wh->minor = wh->major = ~0;
 		wh->type = DEV_ALL;
 		wh->access = ACC_MASK;
+		dev_cgroup->deny_all = false;
 		list_add(&wh->list, &dev_cgroup->whitelist);
 	} else {
 		parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
 		mutex_lock(&devcgroup_mutex);
 		ret = dev_whitelist_copy(&dev_cgroup->whitelist,
 				&parent_dev_cgroup->whitelist);
+		dev_cgroup->deny_all = parent_dev_cgroup->deny_all;
 		mutex_unlock(&devcgroup_mutex);
 		if (ret) {
 			kfree(dev_cgroup);
@@ -409,9 +412,11 @@
 	case DEVCG_ALLOW:
 		if (!parent_has_perm(devcgroup, &wh))
 			return -EPERM;
+		devcgroup->deny_all = false;
 		return dev_whitelist_add(devcgroup, &wh);
 	case DEVCG_DENY:
 		dev_whitelist_rm(devcgroup, &wh);
+		devcgroup->deny_all = true;
 		break;
 	default:
 		return -EINVAL;