linux-kernel - [PATCH 2/3] devcgroup: fix permission check when adding entry to child cgroup

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Date:	Tue, 08 Jul 2008 09:51:09 +0800
From:	Li Zefan <lizf@...fujitsu.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	LKML <linux-kernel@...r.kernel.org>,
	"Serge E. Hallyn" <serue@...ibm.com>,
	Paul Menage <menage@...gle.com>,
	Pavel Emelianov <xemul@...nvz.org>
Subject: [PATCH 2/3] 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@...fujitsu.com>
Acked-by: Serge Hallyn <serue@...ibm.com>
---
 security/device_cgroup.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 1e2e28a..ddd92ce 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;
 	}
-- 
1.5.4.rc3

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