From: Vivek Goyal <vgoyal@redhat.com>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
linux-kernel@vger.kernel.org, pjones@redhat.com, hpa@zytor.com,
dhowells@redhat.com, jwboyer@redhat.com,
Dmitry Kasatkin <dmitry.kasatkin@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary
Date: Wed, 16 Jan 2013 13:28:04 -0500 [thread overview]
Message-ID: <20130116182804.GF29845@redhat.com> (raw)
In-Reply-To: <1358359715.4593.146.camel@falcor1>
On Wed, Jan 16, 2013 at 01:08:35PM -0500, Mimi Zohar wrote:
> On Wed, 2013-01-16 at 11:34 -0500, Vivek Goyal wrote:
>
> > I read the comment in ima_bprm_check() being called from security_bprm_check().
> > It says that files already open for write can't executed and files already
> > open for exec can't be open for writes. That's fine.
> >
> > I was worried about anonymous pages being modified on swap and then
> > faulted back in. It is not necessarily signature verification but making
> > sure signed processes memory is not modified later by any unsigned process
> > in anyway. And that includes disabling ptrace too.
> >
> > So IMA stuff does not do anything to protect against process memory being
> > modified using ptrace or by playing tricks with swap.
>
> > I am not sure what will happen if I can bypass the file system and directly
> > write on a disk block and modify executable. (Assuming one can get block
> > information somehow). Does anything protect such modification? Will IMA
> > detect it?
>
> Sorry, this is out of scope for IMA. Dmitry has looked into this, but
> I'm not sure where it stands at the moment.
Ok, so that's one reason that why I wrote these patcehs. IMA currently
is not doing following things to make sure address space of signed images
is not modified by others.
- Protecting against modifications to pages on swap.
- Protecting against modifications by ptrace.
- Protecting against modifications which bypassed filesystem and directly
wrote to the block.
Locking down all the pages of signed binaries in memory hopefully should
solve above problems.
Thanks
Vivek
next prev parent reply other threads:[~2013-01-16 18:28 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-15 21:34 [PATCH 0/3] ELF executable signing and verification Vivek Goyal
2013-01-15 21:34 ` [PATCH 1/3] module: export couple of functions for use in process signature verification Vivek Goyal
2013-01-15 21:34 ` [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary Vivek Goyal
2013-01-16 4:30 ` Eric W. Biederman
2013-01-16 4:55 ` Mimi Zohar
2013-01-16 7:10 ` Eric W. Biederman
2013-01-16 14:00 ` Mimi Zohar
2013-01-16 14:48 ` Vivek Goyal
2013-01-16 15:33 ` Mimi Zohar
2013-01-16 15:54 ` Vivek Goyal
2013-01-16 17:24 ` Mimi Zohar
2013-01-16 18:21 ` Vivek Goyal
2013-01-16 18:45 ` Mimi Zohar
2013-01-16 18:57 ` Vivek Goyal
2013-01-16 19:37 ` Mimi Zohar
2013-01-16 19:47 ` Vivek Goyal
2013-01-16 20:25 ` Mimi Zohar
2013-01-16 21:55 ` Vivek Goyal
2013-01-17 8:37 ` Elena Reshetova
2013-01-17 14:39 ` Kasatkin, Dmitry
2013-01-17 14:35 ` Kasatkin, Dmitry
2013-01-16 16:34 ` Vivek Goyal
2013-01-16 18:08 ` Mimi Zohar
2013-01-16 18:28 ` Vivek Goyal [this message]
2013-01-16 19:24 ` Mimi Zohar
2013-01-16 21:53 ` Vivek Goyal
2013-01-17 14:58 ` Kasatkin, Dmitry
2013-01-17 15:06 ` Kasatkin, Dmitry
2013-01-17 15:21 ` Vivek Goyal
2013-01-17 15:18 ` Vivek Goyal
2013-01-17 16:27 ` Kasatkin, Dmitry
2013-01-17 20:33 ` Frank Ch. Eigler
2013-01-17 20:55 ` Vivek Goyal
2013-01-17 21:46 ` Kasatkin, Dmitry
2013-01-17 21:52 ` Vivek Goyal
2013-01-20 16:36 ` Mimi Zohar
2013-01-21 16:42 ` Vivek Goyal
2013-01-21 18:30 ` Mimi Zohar
2013-01-16 22:35 ` Mimi Zohar
2013-01-16 22:51 ` Vivek Goyal
2013-01-16 23:16 ` Eric W. Biederman
2013-01-17 15:37 ` Mimi Zohar
2013-01-17 15:51 ` Vivek Goyal
2013-01-17 16:32 ` Mimi Zohar
2013-01-17 17:01 ` Kasatkin, Dmitry
2013-01-17 17:03 ` Kasatkin, Dmitry
2013-01-17 17:42 ` Vivek Goyal
2013-01-17 17:36 ` Vivek Goyal
2013-01-20 17:20 ` Mimi Zohar
2013-01-21 15:45 ` Vivek Goyal
2013-01-21 18:44 ` Mimi Zohar
2013-01-20 16:17 ` H. Peter Anvin
2013-01-20 16:55 ` Mimi Zohar
2013-01-20 17:00 ` H. Peter Anvin
2013-01-15 21:34 ` [PATCH 3/3] binfmt_elf: Do not allow exec() if signed binary has intepreter Vivek Goyal
2013-01-15 21:37 ` [PATCH 4/3] User space utility "signelf" to sign elf executable Vivek Goyal
2013-01-15 22:27 ` [PATCH 0/3] ELF executable signing and verification richard -rw- weinberger
2013-01-15 23:15 ` Vivek Goyal
2013-01-15 23:17 ` richard -rw- weinberger
2013-01-17 16:22 ` Kasatkin, Dmitry
2013-01-17 17:25 ` Vivek Goyal
2013-01-22 4:22 ` Rusty Russell
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