Re: [PATCHv3 2/3] kernel: add support for live patching

From: Thomas Gleixner
Date: Mon Nov 24 2014 - 06:13:41 EST


On Thu, 20 Nov 2014, 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.

To be honest this sounds frightening.

How is determined whether a change can be applied w/o a consistency
mechanism or not?

Thanks,

tglx

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