Re: [PATCH v18 02/25] x86/cet/shstk: Add Kconfig option for user-mode control-flow protection

Yu, Yu-cheng
2021-01-29T20:03:14Z

On 1/29/2021 11:42 AM, Dave Hansen wrote:
> On 1/27/21 1:25 PM, Yu-cheng Yu wrote:
>> + help
>> + Control-flow protection is a hardware security hardening feature
>> + that detects function-return address or jump target changes by
>> + malicious code.
>
> It's not really one feature. I also think it's not worth talking about
> shadow stacks or indirect branch tracking in *here*. Leave that for
> Documentation/.
>
> Just say:
>
> Control-flow protection is a set of hardware features which
> place additional restrictions on indirect branches. These help
> mitigate ROP attacks.
>
> ... and add more in the IBT patches.
>
>> Applications must be enabled to use it, and old
>> + userspace does not get protection "for free".
>> + Support for this feature is present on processors released in
>> + 2020 or later. Enabling this feature increases kernel text size
>> + by 3.7 KB.
>
> Did any CPUs ever get released that have this? If so, name them. If
> not, time to change this to 2021, I think.
>

Ok. I will update this.

Yu-cheng