Re: [PATCH v5 01/10] capabilities: introduce CAP_PERFMON to kernel and user space

[Thomas Gleixner]

Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx> writes:
> On 22.01.2020 17:25, Alexey Budankov wrote:
>> On 22.01.2020 17:07, Stephen Smalley wrote:
>>>> It keeps the implementation simple and readable. The implementation is more
>>>> performant in the sense of calling the API - one capable() call for CAP_PERFMON
>>>> privileged process.
>>>>
>>>> Yes, it bloats audit log for CAP_SYS_ADMIN privileged and unprivileged processes,
>>>> but this bloating also advertises and leverages using more secure CAP_PERFMON
>>>> based approach to use perf_event_open system call.
>>>
>>> I can live with that. We just need to document that when you see
>>> both a CAP_PERFMON and a CAP_SYS_ADMIN audit message for a process,
>>> try only allowing CAP_PERFMON first and see if that resolves the
>>> issue. We have a similar issue with CAP_DAC_READ_SEARCH versus
>>> CAP_DAC_OVERRIDE.
>> 
>> perf security [1] document can be updated, at least, to align and document 
>> this audit logging specifics.
>
> And I plan to update the document right after this patch set is accepted.
> Feel free to let me know of the places in the kernel docs that also
> require update w.r.t CAP_PERFMON extension.

The documentation update wants be part of the patch set and not planned
to be done _after_ the patch set is merged.

Thanks,

        tglx