Re: [PATCH RESEND] fs: Move @f_count to different cacheline with @f_mode

[Aleksa Sarai]

On 2020-08-26, Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx> wrote:
> 在 2020/8/22 0:02, Will Deacon 写道:
> >   - This thing is tagged with __randomize_layout, so it doesn't help anybody
> >     using that crazy plugin
> 
> This patch isolated the @f_count with @f_mode absolutely and we don't care the
> base address of the structure, or I may miss something what you said.

__randomize_layout randomises the order of fields in a structure on each
kernel rebuild (to make attacks against sensitive kernel structures
theoretically harder because the offset of a field is per-build). It is
separate to ASLR or other base-related randomisation. However it depends
on having CONFIG_GCC_PLUGIN_RANDSTRUCT=y and I believe (at least for
distribution kernels) this isn't a widely-used configuration.

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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