From: Kay Sievers Date: Wed, 13 Jan 2010 13:16:36 +0000 (+0100) Subject: Driver-Core: devtmpfs - reset inode permissions before unlinking X-Git-Tag: firefly_0821_release~10186^2~2093 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4e2f0b48d2a85948cef171961b60ccf994ad24dd;p=firefly-linux-kernel-4.4.55.git Driver-Core: devtmpfs - reset inode permissions before unlinking commit 5e31d76f2817bd50258a092a7c5b15b3006fd61c upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 33faaa22a19d..4d809667815e 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -295,6 +295,19 @@ 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)