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authorPavel Emelyanov <xemul@openvz.org>2008-06-05 22:46:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-06-06 11:29:11 -0700
commitd1ee2971f5bd8a16bc5ecfe1b00e14b4fe407c4f (patch)
tree733c51b66dda47216ca1526fdd85004206fd0ec8 /security/device_cgroup.c
parent7db9cfd380205f6b50afdc3bc3619f876a5eaf0d (diff)
downloadconfigs-d1ee2971f5bd8a16bc5ecfe1b00e14b4fe407c4f.tar.gz
devscgroup: make white list more compact in some cases
Consider you added a 'c foo:bar r' permission to some cgroup and then (a bit later) 'c'foo:bar w' for it. After this you'll see the c foo:bar r c foo:bar w lines in a devices.list file. Another example - consider you added 10 'c foo:bar r' permissions to some cgroup (e.g. by mistake). After this you'll see 10 c foo:bar r lines in a list file. This is weird. This situation also has one more annoying consequence. Having many items in a white list makes permissions checking slower, sine it has to walk a longer list. The proposal is to merge permissions for items, that correspond to the same device. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> 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>
Diffstat (limited to 'security/device_cgroup.c')
-rw-r--r--security/device_cgroup.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index f9941a76973..baf348834b6 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -106,7 +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)
@@ -114,7 +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;
}