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Subject: Re: [PATCH v17 00/10] Carry forward IMA measurement log on kexec on
 ARM64
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Rob Herring <robh@kernel.org>,
        Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Cc:     Thiago Jung Bauermann <bauerman@linux.ibm.com>,
        "AKASHI, Takahiro" <takahiro.akashi@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Will Deacon <will@kernel.org>, Joe Perches <joe@perches.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        James Morse <james.morse@arm.com>,
        Sasha Levin <sashal@kernel.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Frank Rowand <frowand.list@gmail.com>,
        vincenzo.frascino@arm.com, Mark Rutland <mark.rutland@arm.com>,
        dmitry.kasatkin@gmail.com, James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Pavel Tatashin <pasha.tatashin@soleen.com>,
        Allison Randal <allison@lohutok.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Matthias Brugger <mbrugger@suse.com>,
        Hsin-Yi Wang <hsinyi@chromium.org>, tao.li@vivo.com,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        Prakhar Srivastava <prsriva@linux.microsoft.com>,
        balajib@linux.microsoft.com, linux-integrity@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        devicetree@vger.kernel.org,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Date:   Wed, 10 Feb 2021 15:55:52 -0500
In-Reply-To: <CAL_JsqLmdqfFF8u=dE+dQz+6ngv=moWkQF8tpZjUCX-vHuvU_w@mail.gmail.com>
References: <20210209182200.30606-1-nramas@linux.microsoft.com>
         <20210210171500.GA2328209@robh.at.kernel.org>
         <5c002c32-bc49-acda-c641-7b1494ea292d@linux.microsoft.com>
         <CAL_JsqLmdqfFF8u=dE+dQz+6ngv=moWkQF8tpZjUCX-vHuvU_w@mail.gmail.com>
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On Wed, 2021-02-10 at 14:42 -0600, Rob Herring wrote:
> On Wed, Feb 10, 2021 at 11:33 AM Lakshmi Ramasubramanian
> <nramas@linux.microsoft.com> wrote:
> >
> > On 2/10/21 9:15 AM, Rob Herring wrote:
> > > On Tue, Feb 09, 2021 at 10:21:50AM -0800, Lakshmi Ramasubramanian wrote:
> > >> On kexec file load Integrity Measurement Architecture (IMA) subsystem
> > >> may verify the IMA signature of the kernel and initramfs, and measure
> > >> it.  The command line parameters passed to the kernel in the kexec call
> > >> may also be measured by IMA.  A remote attestation service can verify
> > >> a TPM quote based on the TPM event log, the IMA measurement list, and
> > >> the TPM PCR data.  This can be achieved only if the IMA measurement log
> > >> is carried over from the current kernel to the next kernel across
> > >> the kexec call.
> > >>
> > >> powerpc already supports carrying forward the IMA measurement log on
> > >> kexec.  This patch set adds support for carrying forward the IMA
> > >> measurement log on kexec on ARM64.
> > >>
> > >> This patch set moves the platform independent code defined for powerpc
> > >> such that it can be reused for other platforms as well.  A chosen node
> > >> "linux,ima-kexec-buffer" is added to the DTB for ARM64 to hold
> > >> the address and the size of the memory reserved to carry
> > >> the IMA measurement log.
> > >>
> > >> This patch set has been tested for ARM64 platform using QEMU.
> > >> I would like help from the community for testing this change on powerpc.
> > >> Thanks.
> > >>
> > >> This patch set is based on
> > >> commit 96acc833dec8 ("ima: Free IMA measurement buffer after kexec syscall")
> > >> in https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
> > >> "next-integrity" branch.
> > >
> > > Is that a hard dependency still? Given this is now almost entirely
> > > deleting arch code and adding drivers/of/ code, I was going to apply it.
> > >
> >
> > I tried applying the patches in Linus' mainline branch -
> > PATCH #5 0005-powerpc-Move-ima-buffer-fields-to-struct-kimage.patch
> > doesn't apply.
> >
> > But if I apply the dependent patch set (link given below), all the
> > patches in this patch set apply fine.
> >
> > https://patchwork.kernel.org/project/linux-integrity/patch/20210204174951.25771-2-nramas@linux.microsoft.com/
> 
> Ideally, we don't apply the same patch in 2 branches. It looks like
> there's a conflict but no real dependence on the above patch (the
> ima_buffer part). The conflict seems trivial enough that Linus can
> resolve it in the merge window.
> 
> Or Mimi can take the whole thing if preferred?

How about I create a topic branch with just the two patches, allowing
both of us to merge it?   There shouldn't be a problem with re-writing
next-integrity history.

Mimi