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From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"Borislav Petkov" <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"H . Peter Anvin" <hpa@zytor.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Sean Christopherson" <seanjc@google.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"Wanpeng Li" <wanpengli@tencent.com>,
	"Alexander Graf" <graf@amazon.com>,
	"Chao Peng" <chao.p.peng@linux.intel.com>,
	"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	"Forrest Yuan Yu" <yuanyu@google.com>,
	"James Gowans" <jgowans@amazon.com>,
	"James Morris" <jamorris@linux.microsoft.com>,
	"John Andersen" <john.s.andersen@intel.com>,
	"Marian Rotariu" <marian.c.rotariu@gmail.com>,
	"Mihai Donțu" <mdontu@bitdefender.com>,
	"Nicușor Cîțu" <nicu.citu@icloud.com>,
	"Thara Gopinath" <tgopinath@microsoft.com>,
	"Trilok Soni" <quic_tsoni@quicinc.com>,
	"Wei Liu" <wei.liu@kernel.org>, "Will Deacon" <will@kernel.org>,
	"Yu Zhang" <yu.c.zhang@linux.intel.com>,
	"Zahra Tarkhani" <ztarkhani@microsoft.com>,
	"Ștefan Șicleru" <ssicleru@bitdefender.com>,
	dev@lists.cloudhypervisor.org, kvm@vger.kernel.org,
	linux-hardening@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org, qemu-devel@nongnu.org,
	virtualization@lists.linux-foundation.org, x86@kernel.org,
	xen-devel@lists.xenproject.org
Subject: Re: [RFC PATCH v2 17/19] heki: x86: Update permissions counters during text patching
Date: Fri, 8 Dec 2023 12:41:31 -0600	[thread overview]
Message-ID: <eb41ec87-8e46-4880-9d94-d86849ddadd2@linux.microsoft.com> (raw)
In-Reply-To: <20231206185134.GA9899@noisy.programming.kicks-ass.net>



On 12/6/23 12:51, Peter Zijlstra wrote:
> On Wed, Dec 06, 2023 at 10:37:33AM -0600, Madhavan T. Venkataraman wrote:
>>
>>
>> On 11/30/23 05:33, Peter Zijlstra wrote:
>>> On Wed, Nov 29, 2023 at 03:07:15PM -0600, Madhavan T. Venkataraman wrote:
>>>
>>>> Kernel Lockdown
>>>> ---------------
>>>>
>>>> But, we must provide at least some security in V2. Otherwise, it is useless.
>>>>
>>>> So, we have implemented what we call a kernel lockdown. At the end of kernel
>>>> boot, Heki establishes permissions in the extended page table as mentioned
>>>> before. Also, it adds an immutable attribute for kernel text and kernel RO data.
>>>> Beyond that point, guest requests that attempt to modify permissions on any of
>>>> the immutable pages will be denied.
>>>>
>>>> This means that features like FTrace and KProbes will not work on kernel text
>>>> in V2. This is a temporary limitation. Once authentication is in place, the
>>>> limitation will go away.
>>>
>>> So either you're saying your patch 17 / text_poke is broken (so why
>>> include it ?!?) or your statement above is incorrect. Pick one.
>>>
>>
>> It has been included so that people can be aware of the changes.
>>
>> I will remove the text_poke() changes from the patchset and send it later when
>> I have some authentication in place. It will make sense then.
> 
> If you know its broken then fucking say so in the Changelog instead of
> wasting everybody's time.. OMG.

It is not broken. It addresses one part of the problem. The other part is WIP.

I am preparing a detailed response to your comments. I ask you to be patient until then. In fact, I would appreciate your input/suggestions on some problems we are trying to solve in this context. I will mention them in my response.

Madhavan


  reply	other threads:[~2023-12-08 18:41 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-13  2:23 [RFC PATCH v2 00/19] Hypervisor-Enforced Kernel Integrity Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 01/19] virt: Introduce Hypervisor Enforced Kernel Integrity (Heki) Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 02/19] KVM: x86: Add new hypercall to lock control registers Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 03/19] KVM: x86: Add notifications for Heki policy configuration and violation Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 04/19] heki: Lock guest control registers at the end of guest kernel init Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 05/19] KVM: VMX: Add MBEC support Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 06/19] KVM: x86: Add kvm_x86_ops.fault_gva() Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 07/19] KVM: x86: Make memory attribute helpers more generic Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 08/19] KVM: x86: Extend kvm_vm_set_mem_attributes() with a mask Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 09/19] KVM: x86: Extend kvm_range_has_memory_attributes() with match_all Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 10/19] KVM: x86: Implement per-guest-page permissions Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 11/19] KVM: x86: Add new hypercall to set EPT permissions Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 12/19] x86: Implement the Memory Table feature to store arbitrary per-page data Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 13/19] heki: Implement a kernel page table walker Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 14/19] heki: x86: Initialize permissions counters for pages mapped into KVA Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 15/19] heki: x86: Initialize permissions counters for pages in vmap()/vunmap() Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 16/19] heki: x86: Update permissions counters when guest page permissions change Mickaël Salaün
2023-11-13  2:23 ` [RFC PATCH v2 17/19] heki: x86: Update permissions counters during text patching Mickaël Salaün
2023-11-13  8:19   ` Peter Zijlstra
2023-11-27 16:48     ` Madhavan T. Venkataraman
2023-11-27 20:08       ` Peter Zijlstra
2023-11-29 21:07         ` Madhavan T. Venkataraman
2023-11-30 11:33           ` Peter Zijlstra
2023-12-06 16:37             ` Madhavan T. Venkataraman
2023-12-06 18:51               ` Peter Zijlstra
2023-12-08 18:41                 ` Madhavan T. Venkataraman [this message]
2023-12-01  0:45           ` Edgecombe, Rick P
2023-12-06 16:41             ` Madhavan T. Venkataraman
2023-11-13  2:23 ` [RFC PATCH v2 18/19] heki: x86: Protect guest kernel memory using the KVM hypervisor Mickaël Salaün
2023-11-13  8:54   ` Peter Zijlstra
2023-11-27 17:05     ` Madhavan T. Venkataraman
2023-11-27 20:03       ` Peter Zijlstra
2023-11-29 19:47         ` Madhavan T. Venkataraman
2023-11-13  2:23 ` [RFC PATCH v2 19/19] virt: Add Heki KUnit tests Mickaël Salaün

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