Driver-Core: devtmpfs - reset inode permissions before unlinking (5e31d76f) · Commits · 戴 / test

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 −0

Original line number	Diff line number	Diff line
		@@ -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)

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