Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 31 Jan 2020 07:58:16 +0100
From: Christophe Leroy <>
To: Russell Currey <>,,
Subject: Re: [PATCH] lkdtm: Test KUAP directional user access unlocks on

Le 31/01/2020 à 07:53, Russell Currey a écrit :
> On Fri, 2020-01-31 at 07:44 +0100, Christophe Leroy wrote:
>> Le 31/01/2020 à 06:31, Russell Currey a écrit :
>>> +	pr_info("attempting bad read at %px with write allowed\n",
>>> ptr);
>>> +	tmp = *ptr;
>>> +	tmp += 0xc0dec0de;
>>> +	prevent_write_to_user(ptr, sizeof(unsigned long));
>> Does it work ? I would have thought that if the read fails the
>> process
>> will die and the following test won't be performed.
> Correct, the ACCESS_USERSPACE test does the same thing.  Splitting this
> into separate R and W tests makes sense, even if it is unlikely that
> one would be broken without the other.

Or once we are using user_access_begin() stuff, we can use 
unsafe_put_user() and unsafe_get_user() which should return an error 
instead of killing the caller.


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.