From 5e31d76f2817bd50258a092a7c5b15b3006fd61c Mon Sep 17 00:00:00 2001
From: Kay Sievers <kay.sievers@vrfy.org>
Date: Wed, 13 Jan 2010 14:16:36 +0100
Subject: [PATCH] Driver-Core: devtmpfs - reset inode permissions before
unlinking
Before unlinking the inode, reset the current permissions of possible
references like hardlinks, so granted permissions can not be retained
across the device lifetime by creating hardlinks, in the unusual case
that there is a user-writable directory on the same filesystem.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/devtmpfs.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 42ae452b36b0c..dac478c6e4608 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -301,6 +301,19 @@ int devtmpfs_delete_node(struct device *dev)
if (dentry->d_inode) {
err = vfs_getattr(nd.path.mnt, dentry, &stat);
if (!err && dev_mynode(dev, dentry->d_inode, &stat)) {
+ struct iattr newattrs;
+ /*
+ * before unlinking this node, reset permissions
+ * of possible references like hardlinks
+ */
+ newattrs.ia_uid = 0;
+ newattrs.ia_gid = 0;
+ newattrs.ia_mode = stat.mode & ~0777;
+ newattrs.ia_valid =
+ ATTR_UID|ATTR_GID|ATTR_MODE;
+ mutex_lock(&dentry->d_inode->i_mutex);
+ notify_change(dentry, &newattrs);
+ mutex_unlock(&dentry->d_inode->i_mutex);
err = vfs_unlink(nd.path.dentry->d_inode,
dentry);
if (!err || err == -ENOENT)