lkml.org 
[lkml]   [2014]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/2] kernel: add support for live patching
On 11/06/2014 06:39 AM, Seth Jennings wrote:
> This commit introduces code for the live patching core. It implements
> an ftrace-based mechanism and kernel interface for doing live patching
> of kernel and kernel module functions.
>
> It represents the greatest common functionality set between kpatch and
> kgraft and can accept patches built using either method.
>
> This first version does not implement any consistency mechanism that
> ensures that old and new code do not run together. In practice, ~90% of
> CVEs are safe to apply in this way, since they simply add a conditional
> check. However, any function change that can not execute safely with
> the old version of the function can _not_ be safely applied in this
> version.
>

[...]

> +/********************************************
> + * Sysfs Interface
> + *******************************************/
> +/*
> + * /sys/kernel/livepatch
> + * /sys/kernel/livepatch/<patch>
> + * /sys/kernel/livepatch/<patch>/enabled
> + * /sys/kernel/livepatch/<patch>/<object>
> + * /sys/kernel/livepatch/<patch>/<object>/<func>
> + * /sys/kernel/livepatch/<patch>/<object>/<func>/new_addr
> + * /sys/kernel/livepatch/<patch>/<object>/<func>/old_addr
> + */

Letting anyone read new_addr and old_addr is a kASLR leak, and I would
argue that showing this information to non-root at all is probably a bad
idea.

Can you make new_addr and old_addr have mode 0600 and
/sys/kernel/livepatch itself have mode 0500? For the latter, an admin
who wants unprivileged users to be able to see it can easily chmod it.

--Andy


\
 
 \ /
  Last update: 2014-11-07 21:01    [W:1.450 / U:0.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site