From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Matthew Garrett <mjg@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Khalid Aziz <khalid@gonehiking.org>,
kexec@lists.infradead.org, horms@verge.net.au,
Dave Young <dyoung@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
linux kernel mailing list <linux-kernel@vger.kernel.org>,
Dmitry Kasatkin <dmitry.kasatkin@intel.com>,
Roberto Sassu <roberto.sassu@polito.it>,
Kees Cook <keescook@chromium.org>
Subject: Re: Kdump with signed images
Date: Fri, 26 Oct 2012 14:37:29 -0400 [thread overview]
Message-ID: <1351276649.18115.217.camel@falcor> (raw)
In-Reply-To: <20121026170609.GB24687@redhat.com>
On Fri, 2012-10-26 at 13:06 -0400, Vivek Goyal wrote:
> On Fri, Oct 26, 2012 at 03:39:16AM +0100, Matthew Garrett wrote:
> > On Thu, Oct 25, 2012 at 09:15:58PM -0400, Mimi Zohar wrote:
> >
> > > On a running system, the package installer, after verifying the package
> > > integrity, would install each file with the associated 'security.ima'
> > > extended attribute. The 'security.evm' digital signature would be
> > > installed with an HMAC, calculated using a system unique key.
> >
> > The idea isn't to prevent /sbin/kexec from being modified after
> > installation - it's to prevent it from being possible to install a
> > system that has a modified /sbin/kexec. Leaving any part of this up to
> > the package installer means that it doesn't solve the problem we're
> > trying to solve here. It must be impossible for the kernel to launch any
> > /sbin/kexec that hasn't been signed by a trusted key that's been built
> > into the kernel, and it must be impossible for anything other than
> > /sbin/kexec to make the kexec system call.
>
> I am kind of lost now so just trying to summarize whatever I have
> learned so far from this thread.
Thanks for summarizing.
> - So say we can sign /sbin/kexec at build time and distros can do that.
> - Verify the signature at exec time using kernel keyring and if
> verification happens successfully, say process gains extra capability.
> - Use this new capability to determine whether kexec_load() will be
> successful or not.
>
> Even if we can do all this, it still has the issue of being able to
> stop the process in user space and replace the code at run time
> and be able to launch unsigned kernel.
>
> So until and unless we have a good solution to verify application's
> integrity/authneticity at the time of kexec_load() system call we
> still have the problem. And I don't think we have come up with a
> solution for that yet (until and unless I missed something).
>
> Thanks
> Vivek
>
Agreed, you need a new LSM/integrity hook.
thanks,
Mimi
next prev parent reply other threads:[~2012-10-26 18:39 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1350588121.30243.7.camel@rhapsody>
[not found] ` <20121018193831.GD18147@redhat.com>
[not found] ` <874nlrv2ni.fsf@xmission.com>
[not found] ` <20121019020630.GA27052@redhat.com>
[not found] ` <877gqnnnf0.fsf@xmission.com>
[not found] ` <20121019143112.GB27052@redhat.com>
[not found] ` <871ugqb4gj.fsf@xmission.com>
[not found] ` <20121023131854.GA16496@redhat.com>
[not found] ` <20121023145920.GD16496@redhat.com>
[not found] ` <87fw552mb4.fsf_-_@xmission.com>
2012-10-24 17:36 ` Kdump with signed images Vivek Goyal
2012-10-25 6:10 ` Mimi Zohar
2012-10-25 14:10 ` Vivek Goyal
2012-10-25 18:40 ` Mimi Zohar
2012-10-25 18:55 ` Vivek Goyal
2012-10-26 1:15 ` Mimi Zohar
2012-10-26 2:39 ` Matthew Garrett
2012-10-26 3:30 ` Eric W. Biederman
2012-10-26 17:06 ` Vivek Goyal
2012-10-26 18:37 ` Mimi Zohar [this message]
2012-11-01 13:10 ` Vivek Goyal
2012-11-01 13:53 ` Vivek Goyal
2012-11-01 14:29 ` Mimi Zohar
2012-11-01 14:43 ` Vivek Goyal
2012-11-01 14:52 ` Matthew Garrett
2012-11-02 13:23 ` Vivek Goyal
2012-11-02 14:29 ` Balbir Singh
2012-11-02 14:36 ` Vivek Goyal
2012-11-03 3:02 ` Balbir Singh
2012-11-02 21:34 ` H. Peter Anvin
2012-11-02 21:32 ` Eric W. Biederman
2012-11-05 18:03 ` Vivek Goyal
2012-11-05 19:44 ` Eric W. Biederman
2012-11-05 20:42 ` Vivek Goyal
2012-11-05 23:01 ` H. Peter Anvin
2012-11-06 19:34 ` Vivek Goyal
2012-11-06 23:51 ` Eric W. Biederman
2012-11-08 19:40 ` Vivek Goyal
2012-11-08 19:45 ` Vivek Goyal
2012-11-08 21:03 ` Eric W. Biederman
2012-11-09 14:39 ` Vivek Goyal
2012-11-15 5:09 ` Eric W. Biederman
2012-11-15 12:56 ` Mimi Zohar
2012-11-08 20:46 ` Mimi Zohar
2012-11-01 14:51 ` Vivek Goyal
2012-11-01 14:57 ` Matthew Garrett
2012-11-01 15:10 ` Khalid Aziz
2012-11-01 16:23 ` Matthew Garrett
2012-11-02 16:57 ` Khalid Aziz
2012-10-26 17:59 ` Mimi Zohar
2012-10-26 18:19 ` Matthew Garrett
2012-10-26 18:25 ` Mimi Zohar
[not found] ` <20121023154123.GA30730@srcf.ucam.org>
[not found] ` <87d309xhmc.fsf_-_@xmission.com>
2012-10-24 17:19 ` [RFC] " Vivek Goyal
2012-10-25 5:43 ` Mimi Zohar
2012-10-25 6:44 ` Kees Cook
2012-10-25 7:01 ` Mimi Zohar
2012-10-25 13:54 ` Vivek Goyal
2012-10-25 19:06 ` Mimi Zohar
2012-10-25 15:39 ` [RFC] Kdump with UEFI secure boot (Re: [PATCH v2] kdump: pass acpi_rsdp= to 2nd kernel for efi booting) Vivek Goyal
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