linux-kernel - Re: [PATCH v2] x86/fsgsbase/64: Fix the base write helper functions

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]

Date:   Thu, 1 Nov 2018 11:15:17 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     "Chang S. Bae" <chang.seok.bae@...el.com>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H . Peter Anvin" <hpa@...or.com>, Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ravi Shankar <ravi.v.shankar@...el.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] x86/fsgsbase/64: Fix the base write helper functions


* Chang S. Bae <chang.seok.bae@...el.com> wrote:

> Factor out the code to change index from the relavant helpers. Now,
> the code is located in do_arch_prctl_64().

typo.

> 
> The helper functions that purport to write the base should just write it
> only. It shouldn't have magic optimizations to change the index.
> 
> putreg() in ptrace does not write the current task, but a stopped task.
> 
> v2: Fix further on the task write functions. Revert the changes on the
> task read helpers.
> 
> Suggested-by: Andy Lutomirski <luto@...nel.org>
> Signed-off-by: Chang S. Bae <chang.seok.bae@...el.com>

But most importantly, the changelog is confusing: please start the 
changelog with outlining the problem in an easy to digest fashion, 
starting with the highest level problem description and then successively 
iterating down towards the details.

The title says 'fix' so I suppose this fixes something, it doesn't just 
'factor out'?

Thanks,

	Ingo