linux-kernel - Re: [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property

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: <202006240844.7BE48D2B5@keescook>
Date:   Wed, 24 Jun 2020 08:45:47 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Will Deacon <will@...nel.org>, Fangrui Song <maskray@...gle.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Mark Rutland <mark.rutland@....com>,
        Peter Collingbourne <pcc@...gle.com>,
        James Morse <james.morse@....com>,
        Borislav Petkov <bp@...e.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Russell King <linux@...linux.org.uk>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Arnd Bergmann <arnd@...db.de>, X86 ML <x86@...nel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        linux-arch <linux-arch@...r.kernel.org>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property

On Wed, Jun 24, 2020 at 05:31:06PM +0200, Ard Biesheuvel wrote:
> On Wed, 24 Jun 2020 at 17:21, Kees Cook <keescook@...omium.org> wrote:
> >
> > On Wed, Jun 24, 2020 at 12:46:32PM +0200, Ard Biesheuvel wrote:
> > > I'm not sure if there is a point to having PAC and/or BTI in the EFI
> > > stub, given that it runs under the control of the firmware, with its
> > > memory mappings and PAC configuration etc.
> >
> > Is BTI being ignored when the firmware runs?
> 
> Given that it requires the 'guarded' attribute to be set in the page
> tables, and the fact that the UEFI spec does not require it for
> executables that it invokes, nor describes any means of annotating
> such executables as having been built with BTI annotations, I think we
> can safely assume that the EFI stub will execute with BTI disabled in
> the foreseeable future.

yaaaaaay. *sigh* How long until EFI catches up?

That said, BTI shouldn't _hurt_, right? If EFI ever decides to enable
it, we'll be ready?

-- 
Kees Cook