From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [tpmdd-devel] [PATCH RESEND 3/3] tpm-chip: Export TPM device to user space even when startup failed Date: Wed, 30 Aug 2017 14:10:19 +0300 Message-ID: <20170830111019.bsd2jod7z2v2jeoi@linux.intel.com> References: <20170824083714.10016-1-Alexander.Steffen@infineon.com> <20170824083714.10016-4-Alexander.Steffen@infineon.com> <20170825172021.lw3ycxqw63ubrcm2@linux.intel.com> <20170829125509.55aylht3ikes3bpy@linux.intel.com> <20170829151739.315ae581@kitsune.suse.cz> <20170830101510.rlkh2p3zecfsrhgl@linux.intel.com> <4722067A-082C-40E7-90ED-29EFB3228765@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <4722067A-082C-40E7-90ED-29EFB3228765@gmx.de> Sender: owner-linux-security-module@vger.kernel.org To: Peter Huewe Cc: tpmdd-devel@lists.sourceforge.net, Michal =?iso-8859-1?Q?Such=E1nek?= , linux-security-module@vger.kernel.org List-Id: tpmdd-devel@lists.sourceforge.net On Wed, Aug 30, 2017 at 12:41:51PM +0200, Peter Huewe wrote: > > > Am 30. August 2017 12:15:10 MESZ schrieb Jarkko Sakkinen : > >On Tue, Aug 29, 2017 at 03:17:39PM +0200, Michal Suchánek wrote: > >> Hello, > >> > >> On Tue, 29 Aug 2017 15:55:09 +0300 > >> Jarkko Sakkinen wrote: > >> > >> > On Mon, Aug 28, 2017 at 05:15:58PM +0000, > >> > Alexander.Steffen@infineon.com wrote: > >> > > But is that just because nobody bothered to implement the > >necessary > >> > > logic or for some other reason? > >> > > >> > We do not want user space to access broken hardware. It's a huge > >risk > >> > for system stability and potentially could be used for evil > >purposes. > >> > > >> > This is not going to mainline as it is not suitable for general > >> > consumption. You must use a patched kernel if you want this. > >> > > >> > /Jarkko > >> > > >> > >> It has been pointed out that userspace applications that use direct > >IO > >> access exist for the purpose. So using a kernel driver is an > >> improvement over that if the interface is otherwise sane. > >> > >> What do you expect is the potential for instability or evil use? > > > >By definition the use of broken hardware can have unpredictable > >effects. > >Use a patched kernel if you want to do it. > > If the s.m.a.r.t selftest of your hard disk fails, you can still > access it, even though the hw selftest says it is broken. > Same situation. Not sure if you can compare these directly although I get your point. Waiting for more comments on this. At the moment I'm still dilated to restricted access because it gives more variables for the future. /Jarkko