linux-kernel - Re: [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary

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: <20130121154501.GA27617@redhat.com>
Date:	Mon, 21 Jan 2013 10:45:01 -0500
From:	Vivek Goyal <vgoyal@...hat.com>
To:	Mimi Zohar <zohar@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, ebiederm@...ssion.com,
	pjones@...hat.com, hpa@...or.com, dhowells@...hat.com,
	jwboyer@...hat.com
Subject: Re: [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary

On Sun, Jan 20, 2013 at 12:20:00PM -0500, Mimi Zohar wrote:
> On Thu, 2013-01-17 at 12:36 -0500, Vivek Goyal wrote:
> > On Thu, Jan 17, 2013 at 11:32:45AM -0500, Mimi Zohar wrote:
> > 
> > [..]
> > > > > At this point, why would you want yet another method for signing files?
> > > > 
> > > > Are you saying that append signature instead of putting them in a section
> > > > or are you saying that just use IMA.
> > > > 
> > > > - For the first, I am fine with appending too if that works better. So
> > > >   what's wrong with current implementation. Just because we append the
> > > >   signatures in case of modules, we should follow the same thing for
> > > >   executables too?
> > > 
> > > No, I was saying that if this patch set were to be upstreamed, then the
> > > signature verification, at least for ELF modules and ELF executables,
> > > should be the same.  The patch would then be a lot smaller.
> > 
> > I don't think that patch is lot smaller. Initially I had written code
> > where signatures were appended. Parsing the signature is little different
> > from module. In case of modules, whole file is already in memory and
> > in case of executables, we are reading selected portions of file in
> > buffer. 
> 
> Have you looked at the original kernel module signature verification
> code as posted by David?  It did something similar, but was not
> upstreamed.

I have. I think keeping code in a section makes stripping of section
easy. Anyway, these sections are not loaded in memory at file exec
time so it should be fine.

So appending signature is easy and I can change the implementation to
do it like modules.

But please give a more stronger reason that why it should be appened
to executable then put in a section.

Thanks
Vivek
--
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/