From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757833Ab2DITEO (ORCPT ); Mon, 9 Apr 2012 15:04:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1026 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757765Ab2DITEM (ORCPT ); Mon, 9 Apr 2012 15:04:12 -0400 Date: Mon, 9 Apr 2012 21:03:50 +0200 From: Oleg Nesterov To: David Howells , Linus Torvalds Cc: Andrew Morton , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/1] cred: copy_process() should clear child->replacement_session_keyring Message-ID: <20120409190350.GA14716@redhat.com> References: <20120409190323.GA14712@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120409190323.GA14712@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- kernel/cred.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/kernel/cred.c b/kernel/cred.c index 97b36ee..e70683d 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -386,6 +386,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) struct cred *new; int ret; + p->replacement_session_keyring = NULL; + if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && -- 1.5.5.1