From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <keescook@chromium.org>
Cc: mtk.manpages@gmail.com, Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Arnd Bergmann <arnd@arndb.de>,
James Morris <james.l.morris@oracle.com>,
Al Viro <viro@zeniv.linux.org.uk>, Eric Paris <eparis@redhat.com>,
Jiri Kosina <jkosina@suse.cz>,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH 1/4] module: add syscall to load module from fd
Date: Thu, 18 Oct 2012 08:30:27 -0700 [thread overview]
Message-ID: <50802093.2000301@zytor.com> (raw)
In-Reply-To: <CAGXu5jJSz8aQiyNk9q3B05SRVm_YE=krg+Y91BU7550AOSRTSw@mail.gmail.com>
On 10/18/2012 08:28 AM, Kees Cook wrote:
>
> The goal for finit_module is to make sure we're getting what's on the
> filesystem, not an arbitrary blob, so we can reason about it for
> security policy.
>
Yes, I get that... although I'm starting to think that that might
actually be a really bad idea.
>> 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?
>
> This makes me very nervous. I worry that it adds needless complexity
> (it'd be many more checks besides "is it MAP_SHARED?", like "does the
> memory region show the whole file?" "is the offset zero?" etc). Also
> are we sure the memory area would be truly be unmodifiable in the case
> where the filesystem is read-only?
You may need to check for PROT_READONLY as well.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-10-18 15:37 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 22:14 [PATCH 1/4] module: add syscall to load module from fd Kees Cook
2012-09-20 22:14 ` [PATCH 2/4] security: introduce kernel_module_from_file hook Kees Cook
2012-09-21 12:42 ` Mimi Zohar
2012-09-20 22:14 ` [PATCH 3/4] ARM: add finit_module syscall to ARM Kees Cook
2012-09-21 13:15 ` Arnd Bergmann
2012-09-21 14:59 ` Russell King
2012-09-21 15:43 ` Kees Cook
2012-09-20 22:15 ` [PATCH 4/4] add finit_module syscall to asm-generic Kees Cook
2012-09-21 2:22 ` [PATCH 1/4] module: add syscall to load module from fd James Morris
2012-09-21 3:07 ` Kees Cook
2012-09-21 3:09 ` Mimi Zohar
2012-09-21 17:56 ` John Johansen
2012-10-03 22:40 ` Kees Cook
2012-10-04 5:39 ` Rusty Russell
2012-10-04 12:50 ` Mimi Zohar
2012-10-05 3:50 ` Rusty Russell
2012-10-05 7:12 ` Kees Cook
2012-10-04 20:28 ` Kees Cook
2012-10-09 21:54 ` Michael Kerrisk
2012-10-09 21:58 ` H. Peter Anvin
2012-10-09 22:03 ` Michael Kerrisk (man-pages)
2012-10-09 22:09 ` H. Peter Anvin
[not found] ` <CAKgNAkjfkbYOQocuGRAKU=0P2CQCvmedhRMJZPnkUMnnxSOsqg@mail.gmail.com>
2012-10-10 5:54 ` Michael Kerrisk (man-pages)
2012-10-11 22:16 ` Rusty Russell
2012-10-12 5:16 ` Michael Kerrisk (man-pages)
2012-10-18 3:12 ` Rusty Russell
2012-10-18 5:39 ` Lucas De Marchi
2012-10-18 12:59 ` Michael Kerrisk (man-pages)
2012-10-22 7:39 ` Rusty Russell
2012-10-23 2:37 ` Lucas De Marchi
2012-10-23 3:40 ` Kees Cook
2012-10-23 4:08 ` Lucas De Marchi
2012-10-23 15:42 ` Kees Cook
2012-10-23 15:45 ` H. Peter Anvin
2012-10-23 16:25 ` Lucas De Marchi
2012-10-24 3:06 ` Rusty Russell
2012-10-23 7:38 ` Michael Kerrisk (man-pages)
2012-10-30 21:57 ` Kees Cook
2012-11-01 1:03 ` Rusty Russell
[not found] ` <87sj97hs5e.fsf-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2012-12-21 0:01 ` Michael Kerrisk
2012-12-21 0:01 ` Michael Kerrisk
2013-01-03 0:12 ` Rusty Russell
2013-01-03 0:12 ` Rusty Russell
[not found] ` <87fw2j5dlj.fsf-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2013-01-06 18:59 ` Michael Kerrisk (man-pages)
2013-01-06 18:59 ` Michael Kerrisk (man-pages)
[not found] ` <CAKgNAkggu9+AuMRqTFeNy9sJVCMcZVRZx43t=svF=gm+P4DnuQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-01-06 20:24 ` Kees Cook
2013-01-06 20:24 ` Kees Cook
[not found] ` <CAGXu5jJXoYO3CzpENAZYANLzySPPjzDVO_qLonqwxUUu1Ux=sg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-01-07 1:41 ` Michael Kerrisk (man-pages)
2013-01-07 1:41 ` Michael Kerrisk (man-pages)
2013-01-09 17:29 ` Lucas De Marchi
2013-01-09 17:29 ` Lucas De Marchi
[not found] ` <CAMOw1v6Jk7adSeppunBe0GaW3w3MREU0_hW68_Fbh2599jctkg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-01-10 0:55 ` Michael Kerrisk (man-pages)
2013-01-10 0:55 ` Michael Kerrisk (man-pages)
2012-10-18 4:24 ` H. Peter Anvin
2012-10-18 8:05 ` Michael Kerrisk (man-pages)
2012-10-18 14:26 ` H. Peter Anvin
2012-10-18 15:28 ` Kees Cook
2012-10-18 15:30 ` H. Peter Anvin [this message]
2012-10-19 2:23 ` Rusty Russell
2012-10-19 2:54 ` H. Peter Anvin
2012-10-19 10:46 ` Alon Ziv
2012-10-20 4:05 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2012-10-04 20:22 [PATCH v5] " Kees Cook
2012-10-04 20:22 ` [PATCH 1/4] " Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=50802093.2000301@zytor.com \
--to=hpa@zytor.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=eparis@redhat.com \
--cc=james.l.morris@oracle.com \
--cc=jkosina@suse.cz \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=mtk.manpages@gmail.com \
--cc=rusty@rustcorp.com.au \
--cc=serge.hallyn@canonical.com \
--cc=viro@zeniv.linux.org.uk \
--cc=zohar@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.