From: Lukas Wunner <lukas@wunner.de>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: David Howells <dhowells@redhat.com>, Linn Crosetto <linn@hpe.com>,
keyrings@vger.kernel.org,
Matthew Garrett <matthew.garrett@nebula.com>,
linux-security-module <linux-security-module@vger.kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 02/16] efi: Get the secure boot status
Date: Mon, 21 Nov 2016 16:17:58 +0100 [thread overview]
Message-ID: <20161121151758.GA1319@wunner.de> (raw)
In-Reply-To: <CAKv+Gu8Lhm=u97hY1y+Y+Ladk=y7pSVNrow8ML1hQUJ9+74B-w@mail.gmail.com>
On Mon, Nov 21, 2016 at 01:14:52PM +0000, Ard Biesheuvel wrote:
> On 21 November 2016 at 12:41, David Howells <dhowells@redhat.com> wrote:
> > Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> >> > Looking in efi_get_secureboot(), is there a reason:
> >> >
> >> > efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
> >> >
> >> > isn't static const?
> >>
> >> Not a good one, no. It used to be static const, but for some reason,
> >> commit 30d7bf034c03 ("efi/arm64: Check SetupMode when determining
> >> Secure Boot status") removed the static and the const (and I reviewed
> >> it and did not complain AFAIR)
> >> I'll gladly take a patch that reinstates that, though.
> >
> > Also, is there a reason that:
> >
> > typedef efi_status_t efi_get_variable_t (efi_char16_t *name, efi_guid_t *vendor, u32 *attr,
> > unsigned long *data_size, void *data);
> >
> > Doesn't have const name and vendor?
>
> Yes, but not a good one either.
>
> Sadly, the prototypes in the UEFI spec completely ignore constness,
> and these definitions are intended to be identical to the ones in the
> spec. This also means, for instance, that most UEFI firmwares stores
> these kinds of GUIDs in read-write memory, which is a potential
> goldmine for hackers, given how GUIDs are UEFI's duct tape, i.e.,
> keeping the world together.
But the spec declares these two parameters as "IN", so it would seem
legal to declare them const, no?
Incidentally I've already prepared commits a couple of days ago to
change the GUID declarations to const everywhere and also change the
get_variable prototype, I was planning to submit them for 4.11... :-)
Thanks,
Lukas
next prev parent reply other threads:[~2016-11-21 15:16 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-16 21:47 [PATCH 00/16] Kernel lockdown David Howells
2016-11-16 21:47 ` [PATCH 01/16] Add the ability to lock down access to the running kernel image David Howells
2016-11-16 22:20 ` Borislav Petkov
2016-11-16 22:40 ` David Howells
2016-12-25 21:20 ` Pavel Machek
2016-12-25 21:44 ` David Howells
2016-11-16 21:47 ` [PATCH 02/16] efi: Get the secure boot status David Howells
2016-11-17 12:37 ` Lukas Wunner
2016-11-22 0:31 ` [PATCH 1/6] x86/efi: Allow invocation of arbitrary runtime services David Howells
2016-11-22 10:20 ` Lukas Wunner
2016-11-22 14:17 ` David Howells
2016-11-22 14:58 ` Joe Perches
2016-11-22 15:52 ` David Howells
2016-11-22 16:25 ` Joe Perches
2016-11-22 16:40 ` David Howells
2016-11-22 16:51 ` Joe Perches
2016-11-22 0:31 ` [PATCH 2/6] arm/efi: " David Howells
2016-11-22 0:31 ` [PATCH 3/6] efi: Add SHIM and image security database GUID definitions David Howells
2016-11-22 0:32 ` [PATCH 4/6] efi: Get the secure boot status David Howells
2016-11-22 10:44 ` Lukas Wunner
2016-11-22 10:49 ` Ard Biesheuvel
2016-11-22 14:47 ` David Howells
2016-11-22 20:30 ` Lukas Wunner
2016-11-23 0:02 ` David Howells
2016-11-22 14:52 ` David Howells
2016-11-22 20:36 ` Lukas Wunner
2016-11-22 14:57 ` David Howells
2016-11-22 0:32 ` [PATCH 5/6] efi: Disable secure boot if shim is in insecure mode David Howells
2016-11-22 13:03 ` Lukas Wunner
2016-11-22 0:32 ` [PATCH 6/6] efi: Add EFI_SECURE_BOOT bit David Howells
2016-11-22 13:04 ` Lukas Wunner
2016-11-21 11:42 ` [PATCH 02/16] efi: Get the secure boot status David Howells
2016-11-21 11:52 ` Ard Biesheuvel
2016-11-21 12:41 ` David Howells
2016-11-21 13:14 ` Ard Biesheuvel
2016-11-21 15:17 ` Lukas Wunner [this message]
2016-11-21 15:25 ` Ard Biesheuvel
2016-11-21 11:46 ` David Howells
2016-11-21 19:58 ` Lukas Wunner
2016-11-16 21:47 ` [PATCH 03/16] efi: Disable secure boot if shim is in insecure mode David Howells
2016-11-16 21:47 ` [PATCH 04/16] efi: Lock down the kernel if booted in secure boot mode David Howells
2016-11-16 21:47 ` [PATCH 05/16] efi: Add EFI_SECURE_BOOT bit David Howells
2016-11-17 21:58 ` Ard Biesheuvel
2016-11-18 11:58 ` Josh Boyer
2016-11-18 12:10 ` Ard Biesheuvel
2016-11-18 17:28 ` David Howells
2016-11-16 21:48 ` [PATCH 06/16] Add a sysrq option to exit secure boot mode David Howells
2016-11-16 21:48 ` [PATCH 07/16] kexec: Disable at runtime if the kernel is locked down David Howells
2016-11-16 21:48 ` [PATCH 08/16] Copy secure_boot flag in boot params across kexec reboot David Howells
2016-11-16 21:48 ` [PATCH 09/16] hibernate: Disable when the kernel is locked down David Howells
2016-11-16 21:48 ` [PATCH 10/16] PCI: Lock down BAR access " David Howells
2016-11-16 21:48 ` [PATCH 11/16] x86: Lock down IO port " David Howells
2016-11-16 21:48 ` [PATCH 12/16] ACPI: Limit access to custom_method " David Howells
2016-11-16 21:48 ` [PATCH 13/16] asus-wmi: Restrict debugfs interface " David Howells
2016-11-16 21:48 ` [PATCH 14/16] Restrict /dev/mem and /dev/kmem " David Howells
2016-11-16 21:49 ` [PATCH 15/16] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2016-11-16 21:49 ` [PATCH 16/16] x86: Restrict MSR access when the kernel is " David Howells
2016-11-16 22:27 ` [PATCH 00/16] Kernel lockdown One Thousand Gnomes
2016-11-21 19:53 ` Ard Biesheuvel
2016-11-30 14:27 ` One Thousand Gnomes
2016-11-16 22:28 ` Justin Forbes
2016-11-21 23:10 ` [PATCH] Lock down drivers that can have io ports, io mem, irqs and dma changed David Howells
2016-11-22 6:12 ` Dominik Brodowski
2016-11-23 12:58 ` David Howells
2016-11-23 19:21 ` Dominik Brodowski
2016-11-24 17:34 ` David Howells
2016-11-24 20:19 ` Dominik Brodowski
2016-11-25 14:49 ` David Howells
2016-11-28 22:32 ` Corey Minyard
2016-11-29 0:11 ` David Howells
2016-11-29 0:23 ` Corey Minyard
2016-11-29 14:03 ` David Howells
2016-11-29 14:35 ` Corey Minyard
2016-11-30 14:41 ` One Thousand Gnomes
2016-11-30 16:25 ` David Howells
2016-11-29 10:40 ` David Howells
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