[PATCH v7 04/11] capsule: authenticate: Add capsule public key in platform's dtb

[Simon Glass]

Hi Sughosh,

On Sun, 6 Aug 2023 at 05:18, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
>
> On Sun, 6 Aug 2023 at 03:42, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Sat, Aug 05, 2023 at 09:03:53AM -0600, Simon Glass wrote:
> > > Hi Sughosh,
> > >
> > > On Sat, 5 Aug 2023 at 05:35, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
> > > >
> > > > The EFI capsule authentication logic in u-boot expects the public key
> > > > in the form of an EFI Signature List(ESL) to be provided as part of
> > > > the platform's dtb. Currently, the embedding of the ESL file into the
> > > > dtb needs to be done manually.
> > > >
> > > > Add a signature node in the u-boot dtsi file and include the public
> > > > key through the capsule-key property. This file is per architecture,
> > > > and is currently being added for sandbox and arm architectures. It
> > > > will have to be added for other architectures which need to enable
> > > > capsule authentication support.
> > > >
> > > > The path to the ESL file is specified through the
> > > > CONFIG_EFI_CAPSULE_ESL_FILE symbol.
> > > >
> > > > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > > > ---
> > > > Changes since V6:
> > > > * Populate the CONFIG_EFI_CAPSULE_ESL_FILE symbol for sandbox and
> > > >   sandbox_flattree which enable capsule authentication.
> > > >
> > > > Note:
> > > > Simon Glass had asked me to rid of the CONFIG_EFI_HAVE_CAPSULE_SUPPORT
> > > > ifdef used in the sandbox' u-boot.dtsi file. However, that results in
> > > > the sandbox_vpl test failing in CI. Hence that check has been kept.
> > > >
> > > >
> > > >  arch/arm/dts/u-boot.dtsi           | 14 ++++++++++++++
> > > >  arch/sandbox/dts/u-boot.dtsi       | 17 +++++++++++++++++
> >
> > We've already had some go-round as to why this basically identical file
> > can't be in like lib/efi_loader/ or something, yes?
>
> Yes, these need to be under the arch/$(ARCH)/dts/ directory for the
> dtc to include them as part of the platform's dts.
>
> >
> > > >  configs/sandbox_defconfig          |  1 +
> > > >  configs/sandbox_flattree_defconfig |  1 +
> > > >  lib/efi_loader/Kconfig             |  9 +++++++++
> > > >  5 files changed, 42 insertions(+)
> > > >  create mode 100644 arch/arm/dts/u-boot.dtsi
> > > >  create mode 100644 arch/sandbox/dts/u-boot.dtsi
> > > >
> > > > diff --git a/arch/arm/dts/u-boot.dtsi b/arch/arm/dts/u-boot.dtsi
> > > > new file mode 100644
> > > > index 0000000000..4f31da4521
> > > > --- /dev/null
> > > > +++ b/arch/arm/dts/u-boot.dtsi
> > > > @@ -0,0 +1,14 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/**
> > > > + * Devicetree file with miscellaneous nodes that will be included
> > > > + * at build time into the DTB. Currently being used for including
> > > > + * capsule related information.
> > > > + */
> > > > +
> > > > +#ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
> > > > +/ {
> > > > +       signature {
> > > > +               capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
> > > > +       };
> > > > +};
> > > > +#endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
> > > > diff --git a/arch/sandbox/dts/u-boot.dtsi b/arch/sandbox/dts/u-boot.dtsi
> > > > new file mode 100644
> > > > index 0000000000..60bd004937
> > > > --- /dev/null
> > > > +++ b/arch/sandbox/dts/u-boot.dtsi
> > > > @@ -0,0 +1,17 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/*
> > > > + * Devicetree file with miscellaneous nodes that will be included
> > > > + * at build time into the DTB. Currently being used for including
> > > > + * capsule related information.
> > > > + *
> > > > + */
> > > > +
> > > > +#ifdef CONFIG_EFI_HAVE_CAPSULE_SUPPORT
> > > > +/ {
> > > > +#ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
> > > > +       signature {
> > > > +               capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
> > > > +       };
> > > > +#endif
> > > > +};
> > > > +#endif /* CONFIG_EFI_HAVE_CAPSULE_SUPPORT */
> >
> > And why are these two different?
>
> For the sandbox's u-boot.dtsi, we need CONFIG_EFI_CAPSULE_AUTHENTICATE
> so that the ESL file is looked for only when capsule authentication is
> enabled. The outer CONFIG_EFI_HAVE_CAPSULE_SUPPORT is to not include
> stuff from this file unless capsule support is enabled. Simon had
> asked me to rid of the outer ifdef, but the sandbox_vpl test fails
> without it.

Did you look at why? From what I can see, it is because you are adding
the multiple-images tag in binman but not updating VPL. This patch
seems to fix it:

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 arch/sandbox/dts/sandbox_vpl.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/sandbox/dts/sandbox_vpl.dtsi
b/arch/sandbox/dts/sandbox_vpl.dtsi
index c7dc00a8d2d..83e7657d5db 100644
--- a/arch/sandbox/dts/sandbox_vpl.dtsi
+++ b/arch/sandbox/dts/sandbox_vpl.dtsi
@@ -4,6 +4,11 @@
  */

 &binman {
+ image: image {
+ };
+};
+
+&image {
  u-boot-tpl-elf {
  no-expanded;
  };

--
2.34.1

I think it makes sense to generate the capsule definition for all
sandbox builds so you can drop the #ifdefs. Once the tests are tidied
up, it won't have that much impact...if it annoys us we can drop it
later. The EFI_CAPSULE_ESL_FILE Kconfig needs to be present always (no
'depends on'), default to "", otherwise you need an annoying #ifdef in
the .dtsi file.

Regards,
Simon