From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755984Ab2DKKr4 (ORCPT ); Wed, 11 Apr 2012 06:47:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11602 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754394Ab2DKKrz (ORCPT ); Wed, 11 Apr 2012 06:47:55 -0400 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: <20120409190350.GA14716@redhat.com> References: <20120409190350.GA14716@redhat.com> <20120409190323.GA14712@redhat.com> To: Oleg Nesterov Cc: dhowells@redhat.com, Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/1] cred: copy_process() should clear child->replacement_session_keyring Date: Wed, 11 Apr 2012 11:47:49 +0100 Message-ID: <14057.1334141269@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Oleg Nesterov wrote: > keyctl_session_to_parent(task) sets ->replacement_session_keyring, > it should be processed and cleared by key_replace_session_keyring(). > > However, this task can fork before it notices TIF_NOTIFY_RESUME and > the new child gets the bogus ->replacement_session_keyring copied by > dup_task_struct(). This is obviously wrong and, if nothing else, this > leads to put_cred(already_freed_cred). > > change copy_creds() to clear this member. If copy_process() fails > before this point the wrong ->replacement_session_keyring doesn't > matter, exit_creds() won't be called. > > Cc: > Signed-off-by: Oleg Nesterov Acked-by: David Howells