[PATCH] powerpc/rtas: Restrict RTAS requests from userspace

[Michael Ellerman]

Andrew Donnellan <ajd at linux.ibm.com> writes:
> On 10/8/20 4:40 pm, Michael Ellerman wrote:
>> Hi ajd,
>> 
>> Thanks for taking care of this.
>> 
>> I was going to merge this as-is, but given it's fixing a long standing
>> issue there's not really a big rush. So a few comments below.
>
> Thanks for the review.
>
>>> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
>>> index a09eba03f180..ec1cae52d8bd 100644
>>> --- a/arch/powerpc/kernel/rtas.c
>>> +++ b/arch/powerpc/kernel/rtas.c
...
>> 
>>> +	{ "ibm,activate-firmware", -1, -1, -1, -1 },
>> 
>> Would it be worth making the indices 1-based, allowing 0 to be the
>> unused value, meaning you only have to initialise the used fields?
>
> 1-based array indices are morally reprehensible. It would make it 
> cleaner but I kind of prefer an obvious and clear constant for unused, idk

In my defence they wouldn't be 1-based, they'd be 0-based but off-by-one :P

I'm happy either way, your choice.

cheers