Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon, 12 Feb 2018 17:25:25 -0800
From: Kees Cook <>
To: Laura Abbott <>
Cc: Igor Stoppa <>, Boris Lukashev <>, 
	Christopher Lameter <>, Matthew Wilcox <>, Jann Horn <>, 
	Jerome Glisse <>, Michal Hocko <>, 
	Christoph Hellwig <>, 
	linux-security-module <>, Linux-MM <>, 
	kernel list <>, 
	Kernel Hardening <>
Subject: Re: [PATCH 4/6] Protectable Memory

On Mon, Feb 12, 2018 at 4:40 PM, Laura Abbott <> wrote:
> On 02/12/2018 03:27 PM, Kees Cook wrote:
>> On Sun, Feb 4, 2018 at 7:05 AM, Igor Stoppa <>
>> wrote:
>>> On 04/02/18 00:29, Boris Lukashev wrote:
>>>> On Sat, Feb 3, 2018 at 3:32 PM, Igor Stoppa <>
>>>> wrote:
>>> [...]
>>>>> What you are suggesting, if I have understood it correctly, is that,
>>>>> when the pool is protected, the addresses already given out, will
>>>>> become
>>>>> traps that get resolved through a lookup table that is built based on
>>>>> the content of each allocation.
>>>>> That seems to generate a lot of overhead, not to mention the fact that
>>>>> it might not play very well with the MMU.
>>>> That is effectively what i'm suggesting - as a form of protection for
>>>> consumers against direct reads of data which may have been corrupted
>>>> by some irrelevant means. In the context of pmalloc, it would probably
>>>> be a separate type of ro+verified pool
>>> ok, that seems more like an extension though.
>>> ATM I am having problems gaining traction to get even the basic merged
>>> :-)
>>> I would consider this as a possibility for future work, unless it is
>>> said that it's necessary for pmalloc to be accepted ...
>> I would agree: let's get basic functionality in first. Both
>> verification and the physmap part can be done separately, IMO.
> Skipping over physmap leaves a pretty big area of exposure that could
> be difficult to solve later. I appreciate this might block basic
> functionality but I don't think we should just gloss over it without
> at least some idea of what we would do.

What's our exposure on physmap for other regions? e.g. things that are
executable, or made read-only later (like __ro_after_init)?


Kees Cook
Pixel Security

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.