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Date: Tue, 9 Jan 2018 18:29:54 -0800
From: Eric Biggers <ebiggers3@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Joe Lawrence <joe.lawrence@redhat.com>,
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        Mikulas Patocka <mpatocka@redhat.com>,
        "Luis R . Rodriguez" <mcgrof@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH 1/7] pipe, sysctl: drop 'min' parameter from
 pipe-max-size converter
Message-ID: <20180110022954.GA931@zzz.localdomain>
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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.

Eric