From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754217Ab2G3Q64 (ORCPT ); Mon, 30 Jul 2012 12:58:56 -0400 Received: from smtp.outflux.net ([198.145.64.163]:54824 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754071Ab2G3Q6y (ORCPT ); Mon, 30 Jul 2012 12:58:54 -0400 Date: Mon, 30 Jul 2012 09:58:49 -0700 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: James Morris , Kees Cook , John Johansen , linux-security-module@vger.kernel.org Subject: [PATCH] Yama: access current->comm directly Message-ID: <20120730165848.GA28288@www.outflux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The core ptrace access checking routine already holds the task lock, so there is no need to use get_task_comm() which just tries to take the lock again. Drop its use and access current->comm directly. Reported-by: Fengguang Wu Suggested-by: Oleg Nesterov Cc: stable@vger.kernel.org Signed-off-by: Kees Cook --- security/yama/yama_lsm.c | 6 ++---- 1 files changed, 2 insertions(+), 4 deletions(-) diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c index 83554ee..20a68ca 100644 --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c @@ -279,12 +279,10 @@ static int yama_ptrace_access_check(struct task_struct *child, } if (rc) { - char name[sizeof(current->comm)]; + /* task_lock is held by the caller, so use comm directly. */ printk_ratelimited(KERN_NOTICE "ptrace of pid %d was attempted by: %s (pid %d)\n", - child->pid, - get_task_comm(name, current), - current->pid); + child->pid, current->comm, current->pid); } return rc; -- 1.7.0.4 -- Kees Cook Chrome OS Security