Received-SPF: pass (google.com: domain of linux-kernel+bounces-65815-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Wed, 14 Feb 2024 19:32:41 +0100
From: Petr =?UTF-8?B?VGVzYcWZw61r?= <petr@tesarici.cz>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: "hpa@zytor.com" <hpa@zytor.com>, "Xu, Pengfei" <pengfei.xu@intel.com>,
 "tglx@linutronix.de" <tglx@linutronix.de>, "luto@kernel.org"
 <luto@kernel.org>, "kirill.shutemov@linux.intel.com"
 <kirill.shutemov@linux.intel.com>, "brgerst@gmail.com" <brgerst@gmail.com>,
 "dwmw@amazon.co.uk" <dwmw@amazon.co.uk>, "corbet@lwn.net" <corbet@lwn.net>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "Li, Xin3"
 <xin3.li@intel.com>, "roberto.sassu@huaweicloud.com"
 <roberto.sassu@huaweicloud.com>, "petr.tesarik1@huawei-partners.com"
 <petr.tesarik1@huawei-partners.com>, "jgg@ziepe.ca" <jgg@ziepe.ca>,
 "x86@kernel.org" <x86@kernel.org>, "bp@alien8.de" <bp@alien8.de>,
 "peterz@infradead.org" <peterz@infradead.org>, "rppt@kernel.org"
 <rppt@kernel.org>, "arnd@arndb.de" <arnd@arndb.de>, "mhiramat@kernel.org"
 <mhiramat@kernel.org>, "oleg@redhat.com" <oleg@redhat.com>,
 "keescook@chromium.org" <keescook@chromium.org>, "Huang, Kai"
 <kai.huang@intel.com>, "jacob.jun.pan@linux.intel.com"
 <jacob.jun.pan@linux.intel.com>, "zegao2021@gmail.com"
 <zegao2021@gmail.com>, "Rodel, Jorg" <jroedel@suse.de>, "mingo@redhat.com"
 <mingo@redhat.com>, "jpoimboe@kernel.org" <jpoimboe@kernel.org>, "Zhang,
 Tina" <tina.zhang@intel.com>, "Hansen, Dave" <dave.hansen@intel.com>,
 "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
 "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
 "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
 "petrtesarik@huaweicloud.com" <petrtesarik@huaweicloud.com>, Kees Cook
 <keescook@chromium.org>
Subject: Re: [PATCH v1 0/8] x86_64 SandBox Mode arch hooks
Message-ID: <20240214193241.7447a082@meshulam.tesarici.cz>
In-Reply-To: <a27c9c32e410fc3582f3593f209cc1cf3b287042.camel@intel.com>
References: <20240214113516.2307-1-petrtesarik@huaweicloud.com>
	<c424618c-d6c6-430a-8975-8851a617204e@intel.com>
	<34B19756-91D3-4DA1-BE76-BD3122C16E95@zytor.com>
	<20240214174143.74a4f10c@meshulam.tesarici.cz>
	<a27c9c32e410fc3582f3593f209cc1cf3b287042.camel@intel.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

(+Cc Kees)

On Wed, 14 Feb 2024 18:14:49 +0000
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com> wrote:

> On Wed, 2024-02-14 at 17:41 +0100, Petr Tesa=C5=99=C3=ADk wrote:
> > Second, a sandbox can run unmodified kernel code and interact
> > directly
> > with other parts of the kernel. It's not really possible with this
> > initial patch series, but the plan is that sandbox mode can share
> > locks
> > with the kernel.
> >=20
> > Third, sandbox code can be trusted for operations like parsing keys
> > for
> > the trusted keychain if the kernel is locked down, i.e. when even a
> > process with UID 0 is not on the same trust level as kernel mode. =20
>=20
> What use case needs to have the sandbox both protected from the kernel
> (trusted operations) and non-privileged (the kernel protected from it
> via CPL3)? It seems like opposite things.

I think I have mentioned one: parsing keys for the trusted keyring. The
parser is complex enough to be potentially buggy, but the security
folks have already dismissed the idea to run it as a user mode helper.

Petr T