tree 189d5d1d40f6f7584304ca23f3f047fbb233e1a0
parent 2fd60da46da76948b8cc561ae8cc902209686253
author Jia-Ju Bai <baijiaju1990@gmail.com> 1563934962 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1564061571 +0200

fs: kernfs: Fix possible null-pointer dereferences in kernfs_path_from_node_locked()

In kernfs_path_from_node_locked(), there is an if statement on line 147
to check whether buf is NULL:
    if (buf)

When buf is NULL, it is used on line 151:
    len += strlcpy(buf + len, parent_str, ...)
and line 158:
    len += strlcpy(buf + len, "/", ...)
and line 160:
    len += strlcpy(buf + len, kn->name, ...)

Thus, possible null-pointer dereferences may occur.

To fix these possible bugs, buf is checked before being used.
If it is NULL, -EINVAL is returned.

These bugs are found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20190724022242.27505-1-baijiaju1990@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>