From: Eric W. Biederman <ebiederm@xmission.com>
Date: Sun, 13 Nov 2011 20:16:43 +0000 (-0800)
Subject: vfs: Don't allow a user namespace root to make device nodes
X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=975d6b3932d43b87a48d2107264ed0c9a7541d8d;p=linux-edison.git

vfs: Don't allow a user namespace root to make device nodes

Safely making device nodes in a container is solvable but simply
having the capability in a user namespace is not sufficient to make
this work.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---

diff --git a/fs/namei.c b/fs/namei.c
index 1898198abc3..701954d68ac 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2560,8 +2560,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 	if (error)
 		return error;
 
-	if ((S_ISCHR(mode) || S_ISBLK(mode)) &&
-	    !ns_capable(inode_userns(dir), CAP_MKNOD))
+	if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
 		return -EPERM;
 
 	if (!dir->i_op->mknod)