linux-kernel - Re: [PATCH] Input: uinput - fix Spectre v1 vulnerability

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]

Message-ID: <20181016172107.GA230131@dtor-ws>
Date:   Tue, 16 Oct 2018 10:21:07 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: uinput - fix Spectre v1 vulnerability

Hi Gustavo,

On Tue, Oct 16, 2018 at 01:13:13PM +0200, Gustavo A. R. Silva wrote:
> setup.code can be indirectly controlled by user-space, hence leading to
> a potential exploitation of the Spectre variant 1 vulnerability.
> 
> This issue was detected with the help of Smatch:
> 
> drivers/input/misc/uinput.c:512 uinput_abs_setup() warn: potential
> spectre issue 'dev->absinfo' [w] (local cap)
> 
> Fix this by sanitizing setup.code before using it to index dev->absinfo.

So we are saying that attacker, by repeatedly calling ioctl(...,
UI_ABS_SETUP, ...) will be able to poison branch predictor and discover
another program or kernel secrets? But uinput is a privileged interface
open to root only, as it allows injecting arbitrary keystrokes into the
kernel. And since only root can use uinput, meh?

Thanks.

-- 
Dmitry