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

[Sughosh Ganu]

hi Simon,

On Sun, 6 Aug 2023 at 00:06, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Sughosh,
>
> On Sat, 5 Aug 2023 at 11:54, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
> >
> > hi Simon,
> >
> > On Sat, 5 Aug 2023 at 20:34, Simon Glass <sjg at chromium.org> 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 +++++++++++++++++
> > > >  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 */
> > > > diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
> > > > index b6c4f735f2..779af4abc8 100644
> > > > --- a/configs/sandbox_defconfig
> > > > +++ b/configs/sandbox_defconfig
> > > > @@ -341,6 +341,7 @@ CONFIG_EFI_RUNTIME_UPDATE_CAPSULE=y
> > > >  CONFIG_EFI_CAPSULE_ON_DISK=y
> > > >  CONFIG_EFI_CAPSULE_FIRMWARE_RAW=y
> > > >  CONFIG_EFI_CAPSULE_AUTHENTICATE=y
> > > > +CONFIG_EFI_CAPSULE_ESL_FILE="../../../board/sandbox/SIGNER.esl"
> > >
> > > Can we avoid the path here, and just use e.g. good.esl ?
> >
> > Unfortunately no. I believe the way incbin works in dts is that it
> > looks for the binary to be included in the same directory as the dts.
> > Which is why I have to point it to the location of the esl relative to
> > the dts.
> >
> > >
> > > Perhaps this could be fixed up later, e.g. by adding the board
> > > directory as an include dir when building the DT?
> >
> > Again, this is not how incbin seems to work in dts. I tried putting
> > the esl in one of the existing include directory locations, but it
> > does not pick the file from those dirs. It works with the assumption
> > that the bin file is to be in the same dir as the dts.
>
> Yes but you can change that. Try adding to the cmd_dtc rule in Makefile.lib:
>
>    -i $(srctree)/board/$(BOARDDIR) \

We already have the

-I$(srctree)/include

and I had tried putting the esl under the include directory, but it
was not found.

-sughosh


>
> [..]
>
> Regards,
> Simon