From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753014AbbAEQAN (ORCPT ); Mon, 5 Jan 2015 11:00:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9722 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129AbbAEQAJ (ORCPT ); Mon, 5 Jan 2015 11:00:09 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <1419863941-16403-1-git-send-email-sasha.levin@oracle.com> References: <1419863941-16403-1-git-send-email-sasha.levin@oracle.com> To: Sasha Levin Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, James Morris , "Serge E. Hallyn" , keyrings@linux-nfs.org (open list:KEYS/KEYRINGS:), linux-security-module@vger.kernel.org (open list:SECURITY SUBSYSTEM) Subject: Re: [PATCH] KEYS: close race between key lookup and freeing MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <30931.1420473588.1@warthog.procyon.org.uk> Date: Mon, 05 Jan 2015 15:59:48 +0000 Message-ID: <30932.1420473588@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sasha Levin wrote: > When a key is being garbage collected, it's key->user would get put before > the ->destroy() callback is called, where the key is removed from it's > respective tracking structures. > > This leaves a key hanging in a semi-invalid state which leaves a window open > for a different task to try an access key->user. An example is > find_keyring_by_name() which would dereference key->user for a key that is > in the process of being garbage collected (where key->user was freed but > ->destroy() wasn't called yet - so it's still present in the linked list). > > This would cause either a panic, or corrupt memory. > > Signed-off-by: Sasha Levin Applied.