Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752938AbdFGXuc (ORCPT ); Wed, 7 Jun 2017 19:50:32 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50518 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752477AbdFGXEF (ORCPT ); Wed, 7 Jun 2017 19:04:05 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: David Howells , Willy Tarreau Subject: [PATCH 3.10 015/250] KEYS: Change the name of the dead type to ".dead" to prevent user access Date: Thu, 8 Jun 2017 00:56:41 +0200 Message-Id: <1496876436-32402-16-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 44 From: David Howells 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 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 Signed-off-by: Willy Tarreau --- security/keys/gc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/keys/gc.c b/security/keys/gc.c index de34c29..2e01e23 100644 --- 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", }; /* -- 2.8.0.rc2.1.gbe9624a