devcgroup: skip superfluous checks when found the DEV_ALL elem

While walking through the whitelist, if the DEV_ALL item is found, no more
check is needed.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 5fda7df..b8186ba 100644 (file)
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -490,7 +490,7 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
 
        list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
                if (wh->type & DEV_ALL)
 
        list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
                if (wh->type & DEV_ALL)

-                       goto acc_check;
+                       goto found;

                if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
                        continue;
                if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
                if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
                        continue;
                if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))


@@ -499,11 +499,12 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
                        continue;
                if (wh->minor != ~0 && wh->minor != iminor(inode))
                        continue;
                        continue;
                if (wh->minor != ~0 && wh->minor != iminor(inode))
                        continue;

-acc_check:
+

                if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
                        continue;
                if ((mask & MAY_READ) && !(wh->access & ACC_READ))
                        continue;
                if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
                        continue;
                if ((mask & MAY_READ) && !(wh->access & ACC_READ))
                        continue;

+found:

                rcu_read_unlock();
                return 0;
        }
                rcu_read_unlock();
                return 0;
        }


@@ -527,7 +528,7 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
 
        list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
                if (wh->type & DEV_ALL)
 
        list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
                if (wh->type & DEV_ALL)

-                       goto acc_check;
+                       goto found;

                if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
                        continue;
                if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
                if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
                        continue;
                if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))


@@ -536,9 +537,10 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
                        continue;
                if (wh->minor != ~0 && wh->minor != MINOR(dev))
                        continue;
                        continue;
                if (wh->minor != ~0 && wh->minor != MINOR(dev))
                        continue;

-acc_check:
+

                if (!(wh->access & ACC_MKNOD))
                        continue;
                if (!(wh->access & ACC_MKNOD))
                        continue;

+found:

                rcu_read_unlock();
                return 0;
        }
                rcu_read_unlock();
                return 0;
        }