From: "H. Peter Anvin" <hpa@zytor.com>
To: ebiederm@xmission.com, Vivek Goyal <vgoyal@redhat.com>
Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
mjg59@srcf.ucam.org, greg@kroah.com
Subject: Re: [PATCH 0/6] kexec: A new system call to allow in kernel loading
Date: Thu, 21 Nov 2013 17:28:38 -0800 [thread overview]
Message-ID: <5cb078ff-e0d3-478b-ba1c-c16d71c32e02@email.android.com> (raw)
In-Reply-To: <8761rl73s7.fsf@xmission.com>
What do you need from ELF?
ebiederm@xmission.com wrote:
>Vivek Goyal <vgoyal@redhat.com> writes:
>
>> Current proposed secureboot implementation disables kexec/kdump
>because
>> it can allow unsigned kernel to run on a secureboot platform. Intial
>> idea was to sign /sbin/kexec binary and let that binary do the kernel
>> signature verification. I had posted RFC patches for this apparoach
>> here.
>>
>> https://lkml.org/lkml/2013/9/10/560
>>
>> Later we had discussion at Plumbers and most of the people thought
>> that signing and trusting /sbin/kexec is becoming complex. So a
>> better idea might be let kernel do the signature verification of
>> new kernel being loaded. This calls for implementing a new system
>call
>> and moving lot of user space code in kernel.
>>
>> kexec_load() system call allows loading a kexec/kdump kernel and jump
>> to that kernel at right time. Though a lot of processing is done in
>> user space which prepares a list of segments/buffers to be loaded and
>> kexec_load() works on that list of segments. It does not know what's
>> contained in those segments.
>>
>> Now a new system call kexec_file_load() is implemented which takes
>> kernel fd and initrd fd as parameters. Now kernel should be able
>> to verify signature of newly loaded kernel.
>>
>> This is an early RFC patchset. I have not done signature handling
>> part yet. This is more of a minimal patch to show how new system
>> call and functionality will look like. Right now it can only handle
>> bzImage with 64bit entry point on x86_64. No EFI, no x86_32 or any
>> other architecture. Rest of the things can be added slowly as need
>> arises. In first iteration, I have tried to address most common use
>case
>> for us.
>>
>> Any feedback is welcome.
>
>Before you are done we need an ELF loader. bzImage really is very
>uninteresting. To the point I am not at all convinced that an in
>kernel
>loader should support it.
>
>There is also a huge missing piece of this in that your purgatory is
>not
>checking a hash of the loaded image before jumping too it. Without
>that
>this is a huge regression at least for the kexec on panic case. We
>absolutely need to check that the kernel sitting around in memory has
>not been corrupted before we let it run very far.
>
>Eric
--
Sent from my mobile phone. Please pardon brevity and lack of formatting.
next prev parent reply other threads:[~2013-11-22 1:29 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-20 17:50 [PATCH 0/6] kexec: A new system call to allow in kernel loading Vivek Goyal
2013-11-20 17:50 ` [PATCH 1/6] kexec: Export vmcoreinfo note size properly Vivek Goyal
2013-11-21 18:59 ` Greg KH
2013-11-21 19:08 ` Vivek Goyal
2013-11-20 17:50 ` [PATCH 2/6] kexec: Move segment verification code in a separate function Vivek Goyal
2013-11-20 17:50 ` [PATCH 3/6] resource: Provide new functions to walk through resources Vivek Goyal
2013-11-20 17:50 ` [PATCH 4/6] kexec: A new system call, kexec_file_load, for in kernel kexec Vivek Goyal
2013-11-21 19:03 ` Greg KH
2013-11-21 19:06 ` Matthew Garrett
2013-11-21 19:13 ` Vivek Goyal
2013-11-21 19:19 ` Matthew Garrett
2013-11-21 19:24 ` Vivek Goyal
2013-11-22 18:57 ` Vivek Goyal
2013-11-23 3:39 ` Eric W. Biederman
2013-11-25 16:39 ` Vivek Goyal
2013-11-26 12:23 ` Eric W. Biederman
2013-11-26 14:27 ` Vivek Goyal
2013-12-19 12:54 ` Torsten Duwe
2013-12-20 14:19 ` Vivek Goyal
2013-12-20 23:11 ` Eric W. Biederman
2013-12-20 23:20 ` Kees Cook
2013-12-21 11:38 ` Torsten Duwe
2014-01-02 20:39 ` Vivek Goyal
2014-01-02 20:56 ` H. Peter Anvin
2014-01-06 21:33 ` Josh Boyer
2014-01-07 4:22 ` H. Peter Anvin
2013-12-20 23:20 ` H. Peter Anvin
2013-12-21 1:32 ` Eric W. Biederman
2013-12-21 3:32 ` H. Peter Anvin
2013-12-21 12:15 ` Torsten Duwe
2013-11-21 19:16 ` Vivek Goyal
2013-11-22 1:03 ` Kees Cook
2013-11-22 2:13 ` Vivek Goyal
2013-11-22 20:42 ` Jiri Kosina
2014-01-17 19:17 ` Vivek Goyal
2013-11-29 3:10 ` Baoquan He
2013-12-02 15:27 ` WANG Chao
2013-12-02 15:44 ` Vivek Goyal
2013-12-04 1:35 ` Baoquan He
2013-12-04 17:19 ` Vivek Goyal
2013-12-04 1:56 ` Baoquan He
2013-12-04 8:19 ` Baoquan He
2013-12-04 17:32 ` Vivek Goyal
2013-11-20 17:50 ` [PATCH 5/6] kexec-bzImage: Support for loading bzImage using 64bit entry Vivek Goyal
2013-11-21 19:07 ` Greg KH
2013-11-21 19:21 ` Vivek Goyal
2013-11-22 15:24 ` H. Peter Anvin
2013-11-28 11:35 ` Baoquan He
2013-12-02 15:36 ` Vivek Goyal
2013-11-20 17:50 ` [PATCH 6/6] kexec: Support for Kexec on panic using new system call Vivek Goyal
2013-11-28 11:28 ` Baoquan He
2013-12-02 15:30 ` Vivek Goyal
2013-12-04 1:51 ` Baoquan He
2013-12-04 17:20 ` Vivek Goyal
2013-12-04 1:41 ` Baoquan He
2013-12-04 17:19 ` Vivek Goyal
2013-11-21 18:58 ` [PATCH 0/6] kexec: A new system call to allow in kernel loading Greg KH
2013-11-21 19:07 ` Vivek Goyal
2013-11-21 19:46 ` Vivek Goyal
2013-11-21 19:06 ` Geert Uytterhoeven
2013-11-21 19:14 ` Vivek Goyal
2013-11-21 23:07 ` Eric W. Biederman
2013-11-22 1:28 ` H. Peter Anvin [this message]
2013-11-22 2:35 ` Vivek Goyal
2013-11-22 2:40 ` H. Peter Anvin
2013-11-22 1:55 ` Vivek Goyal
2013-11-22 9:09 ` Geert Uytterhoeven
2013-11-22 13:30 ` Jiri Kosina
2013-11-22 13:46 ` Vivek Goyal
2013-11-22 13:50 ` Jiri Kosina
2013-11-22 15:33 ` Vivek Goyal
2013-11-22 17:45 ` Kees Cook
2013-11-22 13:43 ` Vivek Goyal
2013-11-22 15:25 ` Geert Uytterhoeven
2013-11-22 15:33 ` Jiri Kosina
2013-11-22 15:57 ` Eric Paris
2013-11-22 16:04 ` Jiri Kosina
2013-11-22 16:08 ` Vivek Goyal
2013-11-22 13:34 ` Eric W. Biederman
2013-11-22 14:19 ` Vivek Goyal
2013-11-22 19:48 ` Greg KH
2013-11-23 3:23 ` Eric W. Biederman
2013-12-04 19:34 ` Vivek Goyal
2013-12-05 4:10 ` Eric W. Biederman
2013-11-25 10:04 ` Michael Holzheu
2013-11-25 15:36 ` Vivek Goyal
2013-11-25 16:15 ` Michael Holzheu
2013-11-22 0:55 ` HATAYAMA Daisuke
2013-11-22 2:03 ` Vivek Goyal
2013-12-03 13:23 ` Baoquan He
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