Commit 206659fc authored by David Howells's avatar David Howells Committed by Ben Hutchings

KEYS: Change the name of the dead type to ".dead" to prevent user access

commit c1644fe0 upstream.

This fixes CVE-2017-6951.

Userspace should not be able to do things with the "dead" key type as it
doesn't have some of the helper functions set upon it that the kernel
needs.  Attempting to use it may cause the kernel to crash.

Fix this by changing the name of the type to ".dead" so that it's rejected
up front on userspace syscalls by key_get_type_from_user().

Though this doesn't seem to affect recent kernels, it does affect older
ones, certainly those prior to:

	commit c06cfb08
	Author: David Howells <dhowells@redhat.com>
	Date:   Tue Sep 16 17:36:06 2014 +0100
	KEYS: Remove key_type::match in favour of overriding default by match_preparse

which went in before 3.18-rc1.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 50282fcb
...@@ -46,7 +46,7 @@ static unsigned long key_gc_flags; ...@@ -46,7 +46,7 @@ static unsigned long key_gc_flags;
* immediately unlinked. * immediately unlinked.
*/ */
struct key_type key_type_dead = { struct key_type key_type_dead = {
.name = "dead", .name = ".dead",
}; };
/* /*
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment