linux-kernel - Re: [PATCH 0/2] Add support to relocate kernel image to mirrored region

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <262cab19-0bca-a088-77a5-6a41f475f4a4@huawei.com>
Date:   Tue, 24 May 2022 09:11:59 +0800
From:   mawupeng <mawupeng1@...wei.com>
To:     <ardb@...nel.org>
CC:     <akpm@...ux-foundation.org>, <catalin.marinas@....com>,
        <will@...nel.org>, <corbet@....net>, <tglx@...utronix.de>,
        <mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
        <x86@...nel.org>, <dvhart@...radead.org>, <andy@...radead.org>,
        <rppt@...nel.org>, <paulmck@...nel.org>, <peterz@...radead.org>,
        <jroedel@...e.de>, <songmuchun@...edance.com>, <macro@...am.me.uk>,
        <frederic@...nel.org>, <W_Armin@....de>, <john.garry@...wei.com>,
        <seanjc@...gle.com>, <tsbogend@...ha.franken.de>,
        <anshuman.khandual@....com>, <chenhuacai@...nel.org>,
        <david@...hat.com>, <gpiccoli@...lia.com>, <mark.rutland@....com>,
        <wangkefeng.wang@...wei.com>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-efi@...r.kernel.org>, <linux-ia64@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>, <linux-mm@...ck.org>,
        <mawupeng1@...wei.com>
Subject: Re: [PATCH 0/2] Add support to relocate kernel image to mirrored
 region



在 2022/5/23 22:41, Ard Biesheuvel 写道:
> On Mon, 23 May 2022 at 03:18, mawupeng <mawupeng1@...wei.com> wrote:
>>
>>
>>
>> 在 2022/5/20 14:52, Ard Biesheuvel 写道:
>>> On Thu, 19 May 2022 at 13:09, mawupeng <mawupeng1@...wei.com> wrote:
>>>>
>>>>
>>>>
>>>> 在 2022/5/7 17:28, mawupeng 写道:
>>>>>
>>>>>
>>>>> 在 2022/5/3 17:58, Ard Biesheuvel 写道:
>>>>>> On Tue, 19 Apr 2022 at 08:43, Wupeng Ma <mawupeng1@...wei.com> wrote:
>>>>>>>
>>>>>>> From: Ma Wupeng <mawupeng1@...wei.com>
>>>>>>>
>>>>>>> Now system image will perfer to be located to mirrored regions both KASLR
>>>>>>> on and off.
>>>>>>>
>>>>>>
>>>>>> Hello Ma Wupeng,
>>>>>>
>>>>>> I wonder if we could simplify this as follows:
>>>>>> - ignore the non-KASLR case for now, and rely on the bootloader  > load the image into mirrored memory if it exists;
>>>>>
>>>>> In grub, memory for static image is allocated via the following path:
>>>>>
>>>>> grub_cmd_linux
>>>>>      kernel = grub_malloc(filelen)
>>>>>      kernel_alloc_addr = grub_efi_allocate_any_pages (kernel_alloc_pages)
>>>>>      grub_memcpy (kernel_addr, kernel, grub_min(filelen, kernel_size))
>>>>>       grub_loader_set (grub_linux_boot, grub_linux_unload, 0)
>>>>>
>>>>> Can we get memory from mirrored region by the following steps:
>>>>> 1. get memory map by calling grub_efi_get_memory_map()
>>>>> 2. iter all memory map to find a suitable mirrored memory area
>>>>> 3. locate kernel image to this area
>>>>>
>>>>> So, if kaslr is not enabled
>>>>>     - grub will load kernel into mirrored region
>>>>> else
>>>>>     - arm64-stub.c will relocate kernel image to mirrored region
>>>>>
>>>>> Is this feasible?
>>>>
>>>> Is this a feasible proposal to relocate the static kernel image itself
>>>> into more reliable memory?
>>>>
>>>
>>> I'm not sure, it all depends on the firmware.
>>>
>>> When GRUB calls LoadImage(), the firmware will reallocate the image
>>> and unpack it there. So it is really the firmware's job to ensure that
>>> the image is loaded into a suitable location.
>>>
>>> I have some code here that implements a EFI based decompressor, and
>>> which loads the kernel image into mirrored memory if it exists,
>>> without the need to move it again. It could trivially be modified to
>>> deal with non-randomized loads as well.
>>>
>>> But the bottom line is that UEFI should expose the ability to target
>>> mirrored memory, hacking around it like this is not a sustainable
>>> approach.
>>
>> Since firmware is responsible for put kernel static image into mirrored
>> region and kernel is responsible for relocate this image into mirrored
>> region if kaslr is enabled. There is no conflict between these two.
>>
>> Can we integrate the kernel part(introduce mirrored support to arm64) first?
>>
> 
> Yes. If you drop the changes related to fake memmap and rebase, please
> resend them after -rc1 is released.

Ok, I will drop the changes related to fake memmap and rebase and then
resend them after -rc1 is released.

Thanks for reviewing.

> .