linux-kernel - Re: [PATCH 1/4] module: add syscall to load module from fd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <508011AD.5080307@zytor.com>
Date:	Thu, 18 Oct 2012 07:26:53 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	mtk.manpages@...il.com
CC:	Rusty Russell <rusty@...tcorp.com.au>,
	Kees Cook <keescook@...omium.org>,
	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Serge Hallyn <serge.hallyn@...onical.com>,
	Arnd Bergmann <arnd@...db.de>,
	James Morris <james.l.morris@...cle.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Eric Paris <eparis@...hat.com>, Jiri Kosina <jkosina@...e.cz>,
	linux-security-module@...r.kernel.org
Subject: Re: [PATCH 1/4] module: add syscall to load module from fd

On 10/18/2012 01:05 AM, Michael Kerrisk (man-pages) wrote:
>>
>> So perhaps what we *should* have is something that points to the module
>> to a (buffer, length) in userspace, and the equivalent of the current
>> init_module() would be open() + mmap() + minit_module() + close()?
>
> So, I don't get it. What are the args you propose for of minit_module()?
>

Nevermind, this is what the current init_module() already takes.

So it sounds like Rusty is objecting to the very notion of tying a 
module to a file descriptor the way the proposed finit_module() system 
call does -- I was confused about the functioning of the *current* 
init_module() system call.

Given that, I have to say I now seriously question the value of 
finit_module().  The kernel can trivially discover if the pointed-to 
memory area is a MAP_SHARED mmap() of a file descriptor and if so which 
file descriptor... why can't we handle this behind the scenes?

	-hpa

P.S. the man page for init_module(2) is seriously out of date...

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/