1 files changed, 28 insertions, 10 deletions

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 4ea583689eec..fd764a0858d0 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -49,10 +49,14 @@ struct dev_cgroup {
         spinlock_t lock;
 };
 
+static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
+{
+        return container_of(s, struct dev_cgroup, css);
+}
+
 static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup)
 {
-        return container_of(cgroup_subsys_state(cgroup, devices_subsys_id),
-                            struct dev_cgroup, css);
+        return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id));
 }
 
 struct cgroup_subsys devices_subsys;
@@ -102,7 +106,7 @@ free_and_exit:
 static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
                         struct dev_whitelist_item *wh)
 {
-        struct dev_whitelist_item *whcopy;
+        struct dev_whitelist_item *whcopy, *walk;
 
         whcopy = kmalloc(sizeof(*whcopy), GFP_KERNEL);
         if (!whcopy)
@@ -110,7 +114,21 @@ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
 
         memcpy(whcopy, wh, sizeof(*whcopy));
         spin_lock(&dev_cgroup->lock);
-        list_add_tail(&whcopy->list, &dev_cgroup->whitelist);
+        list_for_each_entry(walk, &dev_cgroup->whitelist, list) {
+                if (walk->type != wh->type)
+                        continue;
+                if (walk->major != wh->major)
+                        continue;
+                if (walk->minor != wh->minor)
+                        continue;
+
+                walk->access |= wh->access;
+                kfree(whcopy);
+                whcopy = NULL;
+        }
+
+        if (whcopy != NULL)
+                list_add_tail(&whcopy->list, &dev_cgroup->whitelist);
         spin_unlock(&dev_cgroup->lock);
         return 0;
 }
@@ -364,6 +382,8 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
         case 'a':
                 wh.type = DEV_ALL;
                 wh.access = ACC_MASK;
+                wh.major = ~0;
+                wh.minor = ~0;
                 goto handle;
         case 'b':
                 wh.type = DEV_BLOCK;
@@ -502,7 +522,6 @@ struct cgroup_subsys devices_subsys = {
 
 int devcgroup_inode_permission(struct inode *inode, int mask)
 {
-        struct cgroup *cgroup;
         struct dev_cgroup *dev_cgroup;
         struct dev_whitelist_item *wh;
 
@@ -511,8 +530,8 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
                 return 0;
         if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
                 return 0;
-        cgroup = task_cgroup(current, devices_subsys.subsys_id);
-        dev_cgroup = cgroup_to_devcgroup(cgroup);
+        dev_cgroup = css_to_devcgroup(task_subsys_state(current,
+                                devices_subsys_id));
         if (!dev_cgroup)
                 return 0;
 
@@ -543,12 +562,11 @@ acc_check:
 
 int devcgroup_inode_mknod(int mode, dev_t dev)
 {
-        struct cgroup *cgroup;
         struct dev_cgroup *dev_cgroup;
         struct dev_whitelist_item *wh;
 
-        cgroup = task_cgroup(current, devices_subsys.subsys_id);
-        dev_cgroup = cgroup_to_devcgroup(cgroup);
+        dev_cgroup = css_to_devcgroup(task_subsys_state(current,
+                                devices_subsys_id));
         if (!dev_cgroup)
                 return 0;