From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754994AbdKIVyX (ORCPT ); Thu, 9 Nov 2017 16:54:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54058 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754564AbdKIVyV (ORCPT ); Thu, 9 Nov 2017 16:54:21 -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: <20171109130329.3de3f41a@gandalf.local.home> References: <20171109130329.3de3f41a@gandalf.local.home> <11100.1510245732@warthog.procyon.org.uk> To: Steven Rostedt Cc: dhowells@redhat.com, mingo@redhat.com, alexei.starovoitov@gmail.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] Lock down ftrace MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2789.1510264458.1@warthog.procyon.org.uk> Date: Thu, 09 Nov 2017 21:54:19 +0000 Message-ID: <2790.1510264459@warthog.procyon.org.uk> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 09 Nov 2017 21:54:21 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Steven Rostedt wrote: > Actually, I see it being enabled with DYNAMIC_FTRACE not set. Calling > into sysctl and enabling ftrace_enable, will allow the > ftrace_trace_function to be set to something other than ftrace_stub > again, allowing for static function tracing to run too. Hmmm... Okay, I'm not sure what the sysctl achieves in non-dynamic mode. Some of the functions used by ftrace_enable_sysctl() are stubbed out in that case. I was thinking that was stubbed out also, but apparently not. Anyway, ftrace_enable_sysctl() is also prohibited in lockdown mode. David