From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755373Ab1BGXzu (ORCPT ); Mon, 7 Feb 2011 18:55:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42115 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755193Ab1BGXzs (ORCPT ); Mon, 7 Feb 2011 18:55:48 -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: <20110204181324.15313.11611.stgit@warthog.procyon.org.uk> References: <20110204181324.15313.11611.stgit@warthog.procyon.org.uk> To: stable@kernel.org Cc: dhowells@redhat.com, akpm@linux-foundation.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Tetsuo Handa Subject: Re: [PATCH] CRED: Fix kernel panic upon security_file_alloc() failure. Date: Mon, 07 Feb 2011 23:55:20 +0000 Message-ID: <13661.1297122920@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tetsuo Handa In get_empty_filp() since 2.6.29, file_free(f) is called with f->f_cred == NULL when security_file_alloc() returned an error. As a result, kernel will panic() due to put_cred(NULL) call within RCU callback. Fix this bug by assigning f->f_cred before calling security_file_alloc(). Signed-off-by: Tetsuo Handa Signed-off-by: David Howells --- fs/file_table.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index c3e89ad..eb36b6b 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -125,13 +125,13 @@ struct file *get_empty_filp(void) goto fail; percpu_counter_inc(&nr_files); + f->f_cred = get_cred(cred); if (security_file_alloc(f)) goto fail_sec; INIT_LIST_HEAD(&f->f_u.fu_list); atomic_long_set(&f->f_count, 1); rwlock_init(&f->f_owner.lock); - f->f_cred = get_cred(cred); spin_lock_init(&f->f_lock); eventpoll_init_file(f); /* f->f_version: 0 */