Re: [PATCH 1/7] pipe, sysctl: drop 'min' parameter from pipe-max-size converter

Kees Cook
2018-01-10T17:30:16Z

On Tue, Jan 9, 2018 at 6:29 PM, Eric Biggers <ebiggers3@gmail.com> wrote:
> On Tue, Jan 09, 2018 at 02:20:45PM -0800, Kees Cook wrote:
>> On Sun, Jan 7, 2018 at 9:35 PM, Eric Biggers <ebiggers3@gmail.com> wrote:
>> > From: Eric Biggers <ebiggers@google.com>
>> >
>> > Before validating the given value against pipe_min_size,
>> > do_proc_dopipe_max_size_conv() calls round_pipe_size(), which rounds the
>> > value up to pipe_min_size. Therefore, the second check against
>> > pipe_min_size is redundant. Remove it.
>>
>> Well, it's not redundant: it provides a hint to anyone trying to tweak
>> the sysctl about the minimum value. I think this should stay, but that
>> pipe_min_size should be made const.
>>
>> -Kees
>>
>
> It *is* redundant, because it doesn't do anything. round_pipe_size() already
> rounds the value up to the minimum.

Ah, yes, I see it now. Wow are the sysctl functions convoluted here!

Acked-by: Kees Cook <keescook@chromium.org>

-Kees

--
Kees Cook
Pixel Security