From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9776BC43381 for ; Sat, 9 Mar 2019 12:11:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CE5420851 for ; Sat, 9 Mar 2019 12:11:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552133507; bh=4O16E9fNDZhBtoBg6LTzReQUn4q2mpiyZ1WU4MWSeG4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=iGqy67N3YXsT/HWx/Exz3XGBa74vHLvgCpxXH8ZDOuC7SJInRAdyxF4XWORN44Kb+ MdyrVlmFl0nKxaWjXDiIY5o2EscvlZSA1pETfutoesX8WCUo1KwpyrRTw8NNAqwOLQ kF53x8XrMoJhzqOw6u3vt968myXgZF7okNG3DINk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726450AbfCIMLq (ORCPT ); Sat, 9 Mar 2019 07:11:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:44986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726424AbfCIMLq (ORCPT ); Sat, 9 Mar 2019 07:11:46 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 83A6D207E0; Sat, 9 Mar 2019 12:11:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552133505; bh=4O16E9fNDZhBtoBg6LTzReQUn4q2mpiyZ1WU4MWSeG4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UstQIxdr80vytCiqdZlJVcrGphHeWcdUfexy4LUrr5GqWDjmoI7gxcY2EBTd8Nlbl L4WOSXka7zs6p0J1TUaV3dSE+OlroauC0wz6D820epoFGyfkSE5PwDTfkaL+hYqOUA kp7m+OO9z5CEvudx4enMPddudprplFXfE3r4Vr/Y= Date: Sat, 9 Mar 2019 13:11:41 +0100 From: Greg KH To: Geert Uytterhoeven Cc: Joel Fernandes , LKML , Andrew Morton , Alexei Starovoitov , atish patra , Daniel Colascione , Dan Williams , Dietmar Eggemann , Guenter Roeck , Jonathan Corbet , Karim Yaghmour , Kees Cook , Android Kernel Team , "open list:DOCUMENTATION" , "open list:KERNEL SELFTEST FRAMEWORK" , linux-trace-devel@vger.kernel.org, Manoj Rao , Masahiro Yamada , Masami Hiramatsu , Qais Yousef , Randy Dunlap , Steven Rostedt , Shuah Khan , Yonghong Song Subject: Re: [PATCH v4 1/2] Provide in-kernel headers for making it easy to extend the kernel Message-ID: <20190309121141.GA30173@kroah.com> References: <20190301160856.129678-1-joel@joelfernandes.org> <20190307150343.GB258852@google.com> <20190308140251.GC25768@kroah.com> <20190309071648.GE3882@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Sat, Mar 09, 2019 at 12:40:01PM +0100, Geert Uytterhoeven wrote: > > Signing keys should be kept secure, or better yet, just deleted entirely > > after creating and signing with them. That's what I do for my kernels > > and I'm pretty sure that some distros also do this. That way there's no > > chance that someone else can sign a module and have it loaded without > > detection, which is what signing is supposed to prevent from happening. > > If you want that kind of security, there's no point in allowing to extend the > kernel by building more kernel modules after deployment. That's not what these files are for (in the original user's case). They want these for doing tracing/ebpf stuff, which require kernel headers to build against. > "Raw kernel headers also cannot be copied into the filesystem like they > can be on other distros, due to licensing and other issues. There's no > linux-headers package on Android." > > What's the licensing issue? What's the (legal) difference between having > the headers on the file system, and having a kernel module including the > headers on the file system? There is no licensing issue, see my follow-up comment about that. It's all in ease-of-use here. You want to build a trace function against a running kernel, and now you have the header files for that specific kernel right there in the kernel itself to build against. It doesn't get easier than that. thanks, greg k-h