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Date:   Sat, 28 Mar 2020 14:52:55 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Alexey Gladkov <gladkov.alexey@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Kernel Hardening <kernel-hardening@lists.openwall.com>,
        Linux API <linux-api@vger.kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        Linux Security Module <linux-security-module@vger.kernel.org>,
        Akinobu Mita <akinobu.mita@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Daniel Micay <danielmicay@gmail.com>,
        Djalal Harouni <tixxdz@gmail.com>,
        "Dmitry V . Levin" <ldv@altlinux.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Jeff Layton <jlayton@poochiereds.net>,
        Jonathan Corbet <corbet@lwn.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH v10 8/9] proc: use human-readable values for hidehid
Message-ID: <202003281451.88C7CBD23C@keescook>
References: <20200327172331.418878-1-gladkov.alexey@gmail.com>
 <20200327172331.418878-9-gladkov.alexey@gmail.com>
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On Sat, Mar 28, 2020 at 10:14:53PM +0100, Alexey Gladkov wrote:
> On Sat, Mar 28, 2020 at 01:28:28PM -0700, Kees Cook wrote:
> > On Fri, Mar 27, 2020 at 06:23:30PM +0100, Alexey Gladkov wrote:
> > > [...]
> > > +	if (!kstrtouint(param->string, base, &result.uint_32)) {
> > > +		ctx->hidepid = result.uint_32;
> > 
> > This need to bounds-check the value with a call to valid_hidepid(), yes?
> 
> The kstrtouint returns 0 on success and -ERANGE on overflow [1].

No, I mean, hidepid cannot be just any uint32 value. It must be in the
enum. Is that checked somewhere else? It looked like the call to
valid_hidepid() was removed.

-- 
Kees Cook