linux-kernel - Re: [PATCH v2 1/3] fs/exec: don't force writing memory access

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Message-ID: <20160929160901.GB30031@redhat.com>
Date:   Thu, 29 Sep 2016 18:09:01 +0200
From:   Oleg Nesterov <oleg@...hat.com>
To:     Jann Horn <jann@...jh.net>
Cc:     security@...nel.org, Alexander Viro <viro@...iv.linux.org.uk>,
        Paul Moore <paul@...l-moore.com>,
        Stephen Smalley <sds@...ho.nsa.gov>,
        Eric Paris <eparis@...isplace.org>,
        James Morris <james.l.morris@...cle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Nick Kralevich <nnk@...gle.com>,
        Janis Danisevskis <jdanis@...gle.com>,
        linux-security-module@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] fs/exec: don't force writing memory access

On 09/29, Jann Horn wrote:
>
> @@ -204,7 +204,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
>  	 * doing the exec and bprm->mm is the new process's mm.
>  	 */
>  	ret = get_user_pages_remote(current, bprm->mm, pos, 1, write,
> -			1, &page, NULL);
> +			0, &page, NULL);

To me this looks like a reasonable cleanup regardless, FOLL_FORCE
just adds the unnecessary confusion here.

Oleg.