linux-kernel - Re: [PATCH 0/4] x86/ibt: Implement FineIBT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Y1vFDJ9UECgyAkDj@hirez.programming.kicks-ass.net>
Date:   Fri, 28 Oct 2022 14:03:24 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     David Laight <David.Laight@...lab.com>
Cc:     "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Kees Cook <keescook@...omium.org>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Joao Moreira <joao@...rdrivepizza.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH 0/4] x86/ibt: Implement FineIBT

On Fri, Oct 28, 2022 at 11:01:08AM +0000, David Laight wrote:
> From: Peter Zijlstra
> > Sent: 27 October 2022 10:28
> > 
> > Hi all,
> > 
> > Updated FineIBT series; I've (hopefully) incorporated all feedback from last
> > time with the notable exception of the Kconfig CFI default -- I'm not sure we
> > want to add to the Kconfig space for this, also what would a distro do with it.
> > 
> > Anyway; please have a look, I'm hoping to merge this soonish so we can make the
> > next cycle.
> 
> Is there a test to ensure that modules are actually compiled
> with the required endbra, function prologue gap (etc).
> Having the module load fail is somewhat better than a crash.
> 
> It is almost certainly quite easy to generate an out of tree module that
> is missing all of those (even if compiled at the same time as the kernel).
> (Never mind issues with modules that contain binary blobs.)

There is not; it is always possible to load a 'malformed' module. We
have no sanity checking on modules. It is no different from any other
binary compatilibity issue; if you build a dud module, you get to keep
the pieces.