From ec229e830060091b9be63c8f873c1b2407a82821 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizf@cn.fujitsu.com>
Date: Sun, 13 Jul 2008 12:14:04 -0700
Subject: [PATCH] devcgroup: fix permission check when adding entry to child
 cgroup

 # cat devices.list
 c 1:3 r
 # echo 'c 1:3 w' > sub/devices.allow
 # cat sub/devices.list
 c 1:3 w

As illustrated, the parent group has no write permission to /dev/null, so
it's child should not be allowed to add this write permission.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 security/device_cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 1e2e28afba..ddd92cec78 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -300,7 +300,7 @@ static int may_access_whitelist(struct dev_cgroup *c,
 			continue;
 		if (whitem->minor != ~0 && whitem->minor != refwh->minor)
 			continue;
-		if (refwh->access & (~(whitem->access | ACC_MASK)))
+		if (refwh->access & (~whitem->access))
 			continue;
 		return 1;
 	}
-- 
2.39.5