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Date:   Mon, 11 May 2020 15:24:10 -0700
From:   Kees Cook <keescook@chromium.org>
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Jann Horn <jannh@google.com>,
        Greg Ungerer <gerg@linux-m68k.org>,
        Rob Landley <rob@landley.net>,
        Bernd Edlinger <bernd.edlinger@hotmail.de>,
        linux-fsdevel@vger.kernel.org, Al Viro <viro@ZenIV.linux.org.uk>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Casey Schaufler <casey@schaufler-ca.com>,
        linux-security-module@vger.kernel.org,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Andy Lutomirski <luto@amacapital.net>
Subject: Re: [PATCH 5/5] exec: Move the call of prepare_binprm into
 search_binary_handler
Message-ID: <202005111517.27E34BB6@keescook>
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On Sat, May 09, 2020 at 02:42:52PM -0500, Eric W. Biederman wrote:
> 
> The code in prepare_binary_handler needs to be run every time
> search_binary_handler is called so move the call into search_binary_handler
> itself to make the code simpler and easier to understand.
> 
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Yes, nice. :) I don't see any ordering dependencies here. The only thing
I see is a potential for more "work done by kernel before bailing" in
the sense that the arg copying will be performed before we check the
kernel_read() result. I struggle to see how that might be a problem,
and this get us to fewer exec.c exports. Yay!

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

-- 
Kees Cook