Received-SPF: pass (google.com: domain of linux-kernel+bounces-69054-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Message-ID: <c6d0c04a979e05b85acd55d574d56f368c7aa95e.camel@huaweicloud.com>
Subject: Re: [RFC 6/8] KEYS: PGP data parser
From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: "H. Peter Anvin" <hpa@zytor.com>, Matthew Wilcox <willy@infradead.org>, 
	Petr Tesarik <petrtesarik@huaweicloud.com>
Cc: Dave Hansen <dave.hansen@intel.com>, Petr =?UTF-8?Q?Tesa=C5=99=C3=ADk?=
 <petr@tesarici.cz>, Jonathan Corbet <corbet@lwn.net>, Thomas Gleixner
 <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov
 <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>, "maintainer:X86
 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>, Andy Lutomirski
 <luto@kernel.org>, Oleg Nesterov <oleg@redhat.com>, Peter Zijlstra
 <peterz@infradead.org>, Xin Li <xin3.li@intel.com>, Arnd Bergmann
 <arnd@arndb.de>, Andrew Morton <akpm@linux-foundation.org>, Rick Edgecombe
 <rick.p.edgecombe@intel.com>,  Kees Cook <keescook@chromium.org>, "Masami
 Hiramatsu (Google)" <mhiramat@kernel.org>, Pengfei Xu
 <pengfei.xu@intel.com>, Josh Poimboeuf <jpoimboe@kernel.org>, Ze Gao
 <zegao2021@gmail.com>, "Kirill A. Shutemov"
 <kirill.shutemov@linux.intel.com>,  Kai Huang <kai.huang@intel.com>, David
 Woodhouse <dwmw@amazon.co.uk>, Brian Gerst <brgerst@gmail.com>,  Jason
 Gunthorpe <jgg@ziepe.ca>, Joerg Roedel <jroedel@suse.de>, "Mike Rapoport
 (IBM)" <rppt@kernel.org>, Tina Zhang <tina.zhang@intel.com>, Jacob Pan
 <jacob.jun.pan@linux.intel.com>, "open list:DOCUMENTATION"
 <linux-doc@vger.kernel.org>, open list <linux-kernel@vger.kernel.org>,
 David Howells <dhowells@redhat.com>, Petr Tesarik
 <petr.tesarik1@huawei-partners.com>
Date: Fri, 16 Feb 2024 18:13:58 +0100
In-Reply-To: <EC53BCED-0D4C-4561-9041-584378326DD5@zytor.com>
References: <fb4a40c7-af9a-406a-95ab-406595f3ffe5@intel.com>
	 <20240216152435.1575-1-petrtesarik@huaweicloud.com>
	 <20240216152435.1575-7-petrtesarik@huaweicloud.com>
	 <Zc-Q5pVHjngq9lpX@casper.infradead.org>
	 <5916fa3ac3d0ce2ade71e7ed1c9eb6923e374c1f.camel@huaweicloud.com>
	 <EC53BCED-0D4C-4561-9041-584378326DD5@zytor.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.44.4-0ubuntu2 
Precedence: bulk
MIME-Version: 1.0

On Fri, 2024-02-16 at 09:08 -0800, H. Peter Anvin wrote:
> On February 16, 2024 8:53:01 AM PST, Roberto Sassu <roberto.sassu@huaweic=
loud.com> wrote:
> > On Fri, 2024-02-16 at 16:44 +0000, Matthew Wilcox wrote:
> > > On Fri, Feb 16, 2024 at 04:24:33PM +0100, Petr Tesarik wrote:
> > > > From: David Howells <dhowells@redhat.com>
> > > >=20
> > > > Implement a PGP data parser for the crypto key type to use when
> > > > instantiating a key.
> > > >=20
> > > > This parser attempts to parse the instantiation data as a PGP packe=
t
> > > > sequence (RFC 4880) and if it parses okay, attempts to extract a pu=
blic-key
> > > > algorithm key or subkey from it.
> > >=20
> > > I don't understand why we want to do this in-kernel instead of in
> > > userspace and then pass in the actual key.
> >=20
> > Sigh, this is a long discussion.
> >=20
> > PGP keys would be used as a system-wide trust anchor to verify RPM
> > package headers, which already contain file digests that can be used as
> > reference values for kernel-enforced integrity appraisal.
> >=20
> > With the assumptions that:
> >=20
> > - In a locked-down system the kernel has more privileges than root
> > - The kernel cannot offload this task to an user space process due to
> >  insufficient isolation
> >=20
> > the only available option is to do it in the kernel (that is what I got
> > as suggestion).
> >=20
> > Roberto
> >=20
> >=20
>=20
> Ok, at least one of those assumptions is false, and *definitely* this app=
roach seems to be a solution in search of a problem.

I'm looking for a solution to this for a long time. Could you please
explain?

Thanks

Roberto