From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752511Ab1BDSNe (ORCPT ); Fri, 4 Feb 2011 13:13:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36715 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752025Ab1BDSNc (ORCPT ); Fri, 4 Feb 2011 13:13:32 -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 Subject: [PATCH] CRED: Fix kernel panic upon security_file_alloc() failure. To: torvalds@osdl.org, akpm@linux-foundation.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Tetsuo Handa , David Howells Date: Fri, 04 Feb 2011 18:13:24 +0000 Message-ID: <20110204181324.15313.11611.stgit@warthog.procyon.org.uk> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit 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 */