From: Dave Martin <Dave.Martin@arm.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arch <linux-arch@vger.kernel.org>,
linux-efi <linux-efi@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Fangrui Song <maskray@google.com>,
Peter Collingbourne <pcc@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Masahiro Yamada <masahiroy@kernel.org>, X86 ML <x86@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Russell King <linux@armlinux.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
Ingo Molnar <mingo@redhat.com>, James Morse <james.morse@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@suse.de>, Will Deacon <will@kernel.org>,
Nathan Chancellor <natechancellor@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property
Date: Wed, 24 Jun 2020 17:29:19 +0100 [thread overview]
Message-ID: <20200624162919.GH25945@arm.com> (raw)
In-Reply-To: <CAMj1kXHqBs44uukRSdFwA_hcmX_yKVfjqdv9RoPbbu-6Wz+RaA@mail.gmail.com>
On Wed, Jun 24, 2020 at 05:48:41PM +0200, Ard Biesheuvel wrote:
> On Wed, 24 Jun 2020 at 17:45, Kees Cook <keescook@chromium.org> wrote:
> >
> > On Wed, Jun 24, 2020 at 05:31:06PM +0200, Ard Biesheuvel wrote:
> > > On Wed, 24 Jun 2020 at 17:21, Kees Cook <keescook@chromium.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?
> >
>
> Sure. Although I anticipate that we'll need to set some flag in the
> PE/COFF header to enable it, and so any BTI opcodes we emit without
> that will never take effect in practice.
In the meantime, it is possible to build all the in-tree parts of EFI
for BTI, and just turn it off for out-of-tree EFI binaries?
If there's no easy way to do this though, I guess we should wait for /
push for a PE/COFF flag to describe this properly.
Cheers
---Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Martin <Dave.Martin@arm.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arch <linux-arch@vger.kernel.org>,
linux-efi <linux-efi@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Fangrui Song <maskray@google.com>,
Peter Collingbourne <pcc@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Masahiro Yamada <masahiroy@kernel.org>, X86 ML <x86@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Russell King <linux@armlinux.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
Ingo Molnar <mingo@redhat.com>, James Morse <james.morse@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@suse.de>, Will Deacon <will@>
Subject: Re: [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property
Date: Wed, 24 Jun 2020 17:29:19 +0100 [thread overview]
Message-ID: <20200624162919.GH25945@arm.com> (raw)
In-Reply-To: <CAMj1kXHqBs44uukRSdFwA_hcmX_yKVfjqdv9RoPbbu-6Wz+RaA@mail.gmail.com>
On Wed, Jun 24, 2020 at 05:48:41PM +0200, Ard Biesheuvel wrote:
> On Wed, 24 Jun 2020 at 17:45, Kees Cook <keescook@chromium.org> wrote:
> >
> > On Wed, Jun 24, 2020 at 05:31:06PM +0200, Ard Biesheuvel wrote:
> > > On Wed, 24 Jun 2020 at 17:21, Kees Cook <keescook@chromium.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?
> >
>
> Sure. Although I anticipate that we'll need to set some flag in the
> PE/COFF header to enable it, and so any BTI opcodes we emit without
> that will never take effect in practice.
In the meantime, it is possible to build all the in-tree parts of EFI
for BTI, and just turn it off for out-of-tree EFI binaries?
If there's no easy way to do this though, I guess we should wait for /
push for a PE/COFF flag to describe this properly.
Cheers
---Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Martin <Dave.Martin@arm.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
linux-efi <linux-efi@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
Will Deacon <will@kernel.org>,
Nathan Chancellor <natechancellor@gmail.com>,
linux-arch <linux-arch@vger.kernel.org>,
Fangrui Song <maskray@google.com>,
Masahiro Yamada <masahiroy@kernel.org>, X86 ML <x86@kernel.org>,
Russell King <linux@armlinux.org.uk>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@suse.de>,
Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Collingbourne <pcc@google.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
James Morse <james.morse@arm.com>
Subject: Re: [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property
Date: Wed, 24 Jun 2020 17:29:19 +0100 [thread overview]
Message-ID: <20200624162919.GH25945@arm.com> (raw)
In-Reply-To: <CAMj1kXHqBs44uukRSdFwA_hcmX_yKVfjqdv9RoPbbu-6Wz+RaA@mail.gmail.com>
On Wed, Jun 24, 2020 at 05:48:41PM +0200, Ard Biesheuvel wrote:
> On Wed, 24 Jun 2020 at 17:45, Kees Cook <keescook@chromium.org> wrote:
> >
> > On Wed, Jun 24, 2020 at 05:31:06PM +0200, Ard Biesheuvel wrote:
> > > On Wed, 24 Jun 2020 at 17:21, Kees Cook <keescook@chromium.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?
> >
>
> Sure. Although I anticipate that we'll need to set some flag in the
> PE/COFF header to enable it, and so any BTI opcodes we emit without
> that will never take effect in practice.
In the meantime, it is possible to build all the in-tree parts of EFI
for BTI, and just turn it off for out-of-tree EFI binaries?
If there's no easy way to do this though, I guess we should wait for /
push for a PE/COFF flag to describe this properly.
Cheers
---Dave
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-06-24 16:30 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 1:49 [PATCH v3 0/9] Warn on orphan section placement Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 1/9] vmlinux.lds.h: Add .gnu.version* to DISCARDS Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 2/9] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to STABS_DEBUG Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 15:39 ` Arvind Sankar
2020-06-24 15:39 ` Arvind Sankar
2020-06-24 15:39 ` Arvind Sankar
2020-06-24 16:16 ` Fangrui Song
2020-06-24 16:16 ` Fangrui Song
2020-06-24 17:11 ` Arvind Sankar
2020-06-24 17:11 ` Arvind Sankar
2020-06-24 17:11 ` Arvind Sankar
2020-06-24 17:26 ` Fangrui Song
2020-06-24 17:26 ` Fangrui Song
2020-06-24 17:35 ` Arvind Sankar
2020-06-24 17:35 ` Arvind Sankar
2020-06-24 17:35 ` Arvind Sankar
2020-06-24 1:49 ` [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 3:31 ` Fangrui Song
2020-06-24 3:31 ` Fangrui Song
2020-06-24 4:44 ` Kees Cook
2020-06-24 4:44 ` Kees Cook
2020-06-24 10:43 ` Will Deacon
2020-06-24 10:43 ` Will Deacon
2020-06-24 10:46 ` Ard Biesheuvel
2020-06-24 10:46 ` Ard Biesheuvel
2020-06-24 10:46 ` Ard Biesheuvel
2020-06-24 11:26 ` Will Deacon
2020-06-24 11:26 ` Will Deacon
2020-06-24 11:26 ` Will Deacon
2020-06-24 13:48 ` Dave Martin
2020-06-24 13:48 ` Dave Martin
2020-06-24 13:48 ` Dave Martin
2020-06-24 15:26 ` Will Deacon
2020-06-24 15:26 ` Will Deacon
2020-06-24 15:26 ` Will Deacon
2020-06-24 16:26 ` Dave Martin
2020-06-24 16:26 ` Dave Martin
2020-06-24 16:26 ` Dave Martin
2020-06-24 15:21 ` Kees Cook
2020-06-24 15:21 ` Kees Cook
2020-06-24 15:21 ` Kees Cook
2020-06-24 15:31 ` Ard Biesheuvel
2020-06-24 15:31 ` Ard Biesheuvel
2020-06-24 15:31 ` Ard Biesheuvel
2020-06-24 15:45 ` Kees Cook
2020-06-24 15:45 ` Kees Cook
2020-06-24 15:45 ` Kees Cook
2020-06-24 15:48 ` Ard Biesheuvel
2020-06-24 15:48 ` Ard Biesheuvel
2020-06-24 15:48 ` Ard Biesheuvel
2020-06-24 16:29 ` Dave Martin [this message]
2020-06-24 16:29 ` Dave Martin
2020-06-24 16:29 ` Dave Martin
2020-06-24 16:40 ` Ard Biesheuvel
2020-06-24 16:40 ` Ard Biesheuvel
2020-06-24 16:40 ` Ard Biesheuvel
2020-06-24 17:16 ` Dave Martin
2020-06-24 17:16 ` Dave Martin
2020-06-24 17:16 ` Dave Martin
2020-06-24 18:23 ` Ard Biesheuvel
2020-06-24 18:23 ` Ard Biesheuvel
2020-06-24 18:23 ` Ard Biesheuvel
2020-06-24 18:57 ` Ard Biesheuvel
2020-06-24 18:57 ` Ard Biesheuvel
2020-06-24 18:57 ` Ard Biesheuvel
2020-06-24 1:49 ` [PATCH v3 4/9] x86/build: Warn on orphan section placement Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 18:36 ` kernel test robot
2020-06-27 15:44 ` Kees Cook
2020-06-27 15:44 ` Kees Cook
2020-06-29 14:54 ` Marco Elver
2020-06-29 14:54 ` Marco Elver
2020-06-29 15:26 ` Kees Cook
2020-06-29 15:26 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 5/9] x86/boot: " Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 6/9] arm/build: " Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 7/9] arm/boot: " Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 8/9] arm64/build: Use common DISCARDS in linker script Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 1:49 ` [PATCH v3 9/9] arm64/build: Warn on orphan section placement Kees Cook
2020-06-24 1:49 ` Kees Cook
2020-06-24 7:57 ` Will Deacon
2020-06-24 7:57 ` Will Deacon
2020-06-24 15:36 ` Kees Cook
2020-06-24 15:36 ` Kees Cook
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