From 5e31d76f2817bd50258a092a7c5b15b3006fd61c Mon Sep 17 00:00:00 2001 From: Kay Sievers 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 Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/base/devtmpfs.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 42ae452..dac478c 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) -- 2.7.4