From de5ae40870350dc8f4d9dd70cd73410f167a23eb Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 18 Feb 2021 11:08:17 +0100 Subject: [PATCH] debugfs: be more robust at handling improper input in debugfs_lookup() commit bc6de804d36b3709d54fa22bd128cbac91c11526 upstream. debugfs_lookup() doesn't like it if it is passed an illegal name pointer, or if the filesystem isn't even initialized yet. If either of these happen, it will crash the system, so fix it up by properly testing for valid input and that we are up and running before trying to find a file in the filesystem. Cc: "Rafael J. Wysocki" Cc: stable Reported-by: Michael Walle Tested-by: Michael Walle Tested-by: Marc Zyngier Link: https://lore.kernel.org/r/20210218100818.3622317-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- fs/debugfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 7b975dbb2bb4..42b0295465b4 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -293,7 +293,7 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent) { struct dentry *dentry; - if (IS_ERR(parent)) + if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent)) return NULL; if (!parent)