linux-kernel - Re: [PATCH 1/9] x86, pkeys: do not special case protection key 0

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

Date:   Mon, 26 Mar 2018 11:58:59 -0600
From:   Shuah Khan <shuahkh@....samsung.com>
To:     Dave Hansen <dave.hansen@...el.com>, Shuah Khan <shuah@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org
Cc:     linux-mm@...ck.org, stable@...nel.org, linuxram@...ibm.com,
        tglx@...utronix.de, mpe@...erman.id.au, mingo@...nel.org,
        akpm@...ux-foundation.org, Shuah Khan <shuahkh@....samsung.com>,
        Shuah Khan <shuahkh@....samsung.com>
Subject: Re: [PATCH 1/9] x86, pkeys: do not special case protection key 0

On 03/26/2018 11:53 AM, Dave Hansen wrote:
> On 03/26/2018 10:47 AM, Shuah Khan wrote:
>>
>> Also what happens "pkey_free() pkey-0" - can you elaborate more on that
>> "silliness consequences"
> 
> It's just what happens if you free any other pkey that is in use: it
> might get reallocated later.  The most likely scenario is that you will
> get pkey-0 back from pkey_alloc(), you will set an access-disable or
> write-disable bit in PKRU for it, and your next stack access will SIGSEGV.
> 

Thanks. This will good information to include in the commit log.

-- Shuah