Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH V5 0/5] KVM: X86: Introducing ROE Protection Kernel
 Hardening
To:     Ahmed Abd El Mawgood <ahmedsoliman0x666@gmail.com>,
        Paolo Bonzini <pbonzini@redhat.com>, rkrcmar@redhat.com,
        Jonathan Corbet <corbet@lwn.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        ovich00@gmail.com, kernel-hardening@lists.openwall.com,
        nigel.edwards@hpe.com, Boris Lukashev <blukashev@sempervictus.com>,
        Hossam Hassan <7ossam9063@gmail.com>,
        Ahmed Lotfy <A7med.lotfey@gmail.com>
References: <20181026151223.16810-1-ahmedsoliman0x666@gmail.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Openpgp: preference=signencrypt
Autocrypt: addr=borntraeger@de.ibm.com; prefer-encrypt=mutual; keydata=
 xsFNBE6cPPgBEAC2VpALY0UJjGmgAmavkL/iAdqul2/F9ONz42K6NrwmT+SI9CylKHIX+fdf
 J34pLNJDmDVEdeb+brtpwC9JEZOLVE0nb+SR83CsAINJYKG3V1b3Kfs0hydseYKsBYqJTN2j
 CmUXDYq9J7uOyQQ7TNVoQejmpp5ifR4EzwIFfmYDekxRVZDJygD0wL/EzUr8Je3/j548NLyL
 4Uhv6CIPf3TY3/aLVKXdxz/ntbLgMcfZsDoHgDk3lY3r1iwbWwEM2+eYRdSZaR4VD+JRD7p8
 0FBadNwWnBce1fmQp3EklodGi5y7TNZ/CKdJ+jRPAAnw7SINhSd7PhJMruDAJaUlbYaIm23A
 +82g+IGe4z9tRGQ9TAflezVMhT5J3ccu6cpIjjvwDlbxucSmtVi5VtPAMTLmfjYp7VY2Tgr+
 T92v7+V96jAfE3Zy2nq52e8RDdUo/F6faxcumdl+aLhhKLXgrozpoe2nL0Nyc2uqFjkjwXXI
 OBQiaqGeWtxeKJP+O8MIpjyGuHUGzvjNx5S/592TQO3phpT5IFWfMgbu4OreZ9yekDhf7Cvn
 /fkYsiLDz9W6Clihd/xlpm79+jlhm4E3xBPiQOPCZowmHjx57mXVAypOP2Eu+i2nyQrkapaY
 IdisDQfWPdNeHNOiPnPS3+GhVlPcqSJAIWnuO7Ofw1ZVOyg/jwARAQABzTRDaHJpc3RpYW4g
 Qm9ybnRyYWVnZXIgKElCTSkgPGJvcm50cmFlZ2VyQGRlLmlibS5jb20+wsF4BBMBAgAiBQJO
 nDz4AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRARe7yAtaYcfOYVD/9sqc6ZdYKD
 bmDIvc2/1LL0g7OgiA8pHJlYN2WHvIhUoZUIqy8Sw2EFny/nlpPVWfG290JizNS2LZ0mCeGZ
 80yt0EpQNR8tLVzLSSr0GgoY0lwsKhAnx3p3AOrA8WXsPL6prLAu3yJI5D0ym4MJ6KlYVIjU
 ppi4NLWz7ncA2nDwiIqk8PBGxsjdc/W767zOOv7117rwhaGHgrJ2tLxoGWj0uoH3ZVhITP1z
 gqHXYaehPEELDV36WrSKidTarfThCWW0T3y4bH/mjvqi4ji9emp1/pOWs5/fmd4HpKW+44tD
 Yt4rSJRSa8lsXnZaEPaeY3nkbWPcy3vX6qafIey5d8dc8Uyaan39WslnJFNEx8cCqJrC77kI
 vcnl65HaW3y48DezrMDH34t3FsNrSVv5fRQ0mbEed8hbn4jguFAjPt4az1xawSp0YvhzwATJ
 YmZWRMa3LPx/fAxoolq9cNa0UB3D3jmikWktm+Jnp6aPeQ2Db3C0cDyxcOQY/GASYHY3KNra
 z8iwS7vULyq1lVhOXg1EeSm+lXQ1Ciz3ub3AhzE4c0ASqRrIHloVHBmh4favY4DEFN19Xw1p
 76vBu6QjlsJGjvROW3GRKpLGogQTLslbjCdIYyp3AJq2KkoKxqdeQYm0LZXjtAwtRDbDo71C
 FxS7i/qfvWJv8ie7bE9A6Wsjn87BTQROnDz4ARAAmPI1e8xB0k23TsEg8O1sBCTXkV8HSEq7
 JlWz7SWyM8oFkJqYAB7E1GTXV5UZcr9iurCMKGSTrSu3ermLja4+k0w71pLxws859V+3z1jr
 nhB3dGzVZEUhCr3EuN0t8eHSLSMyrlPL5qJ11JelnuhToT6535cLOzeTlECc51bp5Xf6/XSx
 SMQaIU1nDM31R13o98oRPQnvSqOeljc25aflKnVkSfqWSrZmb4b0bcWUFFUKVPfQ5Z6JEcJg
 Hp7qPXHW7+tJTgmI1iM/BIkDwQ8qe3Wz8R6rfupde+T70NiId1M9w5rdo0JJsjKAPePKOSDo
 RX1kseJsTZH88wyJ30WuqEqH9zBxif0WtPQUTjz/YgFbmZ8OkB1i+lrBCVHPdcmvathknAxS
 bXL7j37VmYNyVoXez11zPYm+7LA2rvzP9WxR8bPhJvHLhKGk2kZESiNFzP/E4r4Wo24GT4eh
 YrDo7GBHN82V4O9JxWZtjpxBBl8bH9PvGWBmOXky7/bP6h96jFu9ZYzVgIkBP3UYW+Pb1a+b
 w4A83/5ImPwtBrN324bNUxPPqUWNW0ftiR5b81ms/rOcDC/k/VoN1B+IHkXrcBf742VOLID4
 YP+CB9GXrwuF5KyQ5zEPCAjlOqZoq1fX/xGSsumfM7d6/OR8lvUPmqHfAzW3s9n4lZOW5Jfx
 bbkAEQEAAcLBXwQYAQIACQUCTpw8+AIbDAAKCRARe7yAtaYcfPzbD/9WNGVf60oXezNzSVCL
 hfS36l/zy4iy9H9rUZFmmmlBufWOATjiGAXnn0rr/Jh6Zy9NHuvpe3tyNYZLjB9pHT6mRZX7
 Z1vDxeLgMjTv983TQ2hUSlhRSc6e6kGDJyG1WnGQaqymUllCmeC/p9q5m3IRxQrd0skfdN1V
 AMttRwvipmnMduy5SdNayY2YbhWLQ2wS3XHJ39a7D7SQz+gUQfXgE3pf3FlwbwZhRtVR3z5u
 aKjxqjybS3Ojimx4NkWjidwOaUVZTqEecBV+QCzi2oDr9+XtEs0m5YGI4v+Y/kHocNBP0myd
 pF3OoXvcWdTb5atk+OKcc8t4TviKy1WCNujC+yBSq3OM8gbmk6NwCwqhHQzXCibMlVF9hq5a
 FiJb8p4QKSVyLhM8EM3HtiFqFJSV7F+h+2W0kDyzBGyE0D8z3T+L3MOj3JJJkfCwbEbTpk4f
 n8zMboekuNruDw1OADRMPlhoWb+g6exBWx/YN4AY9LbE2KuaScONqph5/HvJDsUldcRN3a5V
 RGIN40QWFVlZvkKIEkzlzqpAyGaRLhXJPv/6tpoQaCQQoSAc5Z9kM/wEd9e2zMeojcWjUXgg
 oWj8A/wY4UXExGBu+UCzzP/6sQRpBiPFgmqPTytrDo/gsUGqjOudLiHQcMU+uunULYQxVghC
 syiRa+UVlsKmx1hsEg==
Date:   Tue, 30 Oct 2018 18:31:38 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <20181026151223.16810-1-ahmedsoliman0x666@gmail.com>
Content-Language: en-US
Message-Id: <e778a30c-f32e-eb4c-5492-21c81926b87f@de.ibm.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 10/26/2018 05:12 PM, Ahmed Abd El Mawgood wrote:
> This is the 5th version which is 4th version with minor fixes. ROE is a 
> hypercall that enables host operating system to restrict guest's access to its
> own memory. This will provide a hardening mechanism that can be used to stop
> rootkits from manipulating kernel static data structures and code. Once a memory
> region is protected the guest kernel can't even request undoing the protection.

At the KVM forum we considered this as something that could be implemented across
multiple architectures. Yes, there will be architecture specific implementations 
and yes some  architectures might be not able to provide everything (e.g. sub-page
granularity).
But we should really check if we can come up with a guest interface or guest common 
code that can be useful across architectures.
> 
> Memory protected by ROE should be non-swapable because even if the ROE protected
> page got swapped out, It won't be possible to write anything in its place.
> 
> ROE hypercall should be capable of either protecting a whole memory frame or
> parts of it. With these two, it should be possible for guest kernel to protect
> its memory and all the page table entries for that memory inside the page table.
> I am still not sure whether this should be part of ROE job or the guest's job.
> 
> 
> The reason why it would be better to implement this from inside kvm: instead of
> (host) user space is the need to access SPTEs to modify the permissions, while
> mprotect() from user space can work in theory. It will become a big performance
> hit to vmexit and switch to user space mode on each fault, on the other hand,
> having the permission handled by EPT should make some remarkable performance
> gain.
> 
> Our model assumes that an attacker got full root access to a running guest and
> his goal is to manipulate kernel code/data (hook syscalls, overwrite IDT ..etc).
> 
> There is future work in progress to also put some sort of protection on the page
> table register CR3 and other critical registers that can be intercepted by KVM.
> This way it won't be possible for an attacker to manipulate any part of the
> guests page table.
> 
> V4->V5 change log:
> - Fixed summary (it was reverted summary)
> - Fixed an inaccurate documentation in patch [4/5]
> 
> Summary:
> 
>  Documentation/virtual/kvm/hypercalls.txt |  40 +++++
>  arch/x86/include/asm/kvm_host.h          |  11 +-
>  arch/x86/kvm/Kconfig                     |   7 +
>  arch/x86/kvm/mmu.c                       | 129 ++++++++++----
>  arch/x86/kvm/vmx.c                       |   2 +-
>  arch/x86/kvm/x86.c                       | 281 ++++++++++++++++++++++++++++++-
>  include/linux/kvm_host.h                 |  29 ++++
>  include/uapi/linux/kvm_para.h            |   5 +
>  virt/kvm/kvm_main.c                      | 119 +++++++++++--
>  9 files changed, 572 insertions(+), 51 deletions(-)
> 
> Signed-off-by: Ahmed Abd El Mawgood <ahmedsoliman0x666@gmail.com>
>