This is a note to let you know that I've just added the patch titled
KEYS: Change the name of the dead type to ".dead" to prevent user access
to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
keys-change-the-name-of-the-dead-type-to-.dead-to-prevent-user-access.patch
and it can be found in the queue-4.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c1644fe041ebaf6519f6809146a77c3ead9193af Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@xxxxxxxxxx>
Date: Tue, 18 Apr 2017 15:31:08 +0100
Subject: KEYS: Change the name of the dead type to ".dead" to prevent user access
From: David Howells <dhowells@xxxxxxxxxx>
commit c1644fe041ebaf6519f6809146a77c3ead9193af 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 c06cfb08b88dfbe13be44a69ae2fdc3a7c902d81
Author: David Howells <dhowells@xxxxxxxxxx>
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: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/keys/gc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -46,7 +46,7 @@ static unsigned long key_gc_flags;
* immediately unlinked.
*/
struct key_type key_type_dead = {
- .name = "dead",
+ .name = ".dead",
};
/*
Patches currently in stable-queue which might be from dhowells@xxxxxxxxxx are
queue-4.10/keys-disallow-keyrings-beginning-with-.-to-be-joined-as-session-keyrings.patch
queue-4.10/keys-change-the-name-of-the-dead-type-to-.dead-to-prevent-user-access.patch
queue-4.10/keys-fix-keyctl_set_reqkey_keyring-to-not-leak-thread-keyrings.patch