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From: Vivek Goyal <vgoyal@redhat.com>
To: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: mjg59@srcf.ucam.org, greg@kroah.com, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	hpa@zytor.com
Subject: Re: [PATCH 0/6] kexec: A new system call to allow in kernel loading
Date: Mon, 25 Nov 2013 10:36:20 -0500	[thread overview]
Message-ID: <20131125153620.GA23094@redhat.com> (raw)
In-Reply-To: <20131125110428.4bae2fe7@holzheu>

On Mon, Nov 25, 2013 at 11:04:28AM +0100, Michael Holzheu wrote:
> On Fri, 22 Nov 2013 05:34:03 -0800
> ebiederm@xmission.com (Eric W. Biederman) wrote:
> 
> > Vivek Goyal <vgoyal@redhat.com> writes:
> 
> > >> 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.
> > >
> > > Agreed. This should not be hard. It is just a matter of calcualting
> > > digest of segments. I will store it in kimge and verify digest again
> > > before passing control to control page. Will fix it in next version.
> > 
> > Nak.  The verification needs to happen in purgatory. 
> > 
> > The verification needs to happen in code whose runtime environment is
> > does not depend on random parts of the kernel.  Anything else is a
> > regression in maintainability and reliability.
> 
> Hello Vivek,
> 
> Just to be sure that you have not forgotten the following s390 detail:
> 
> On s390 we first call purgatory with parameter "0" for doing the
> checksum test. If this fails, we can have as backup solution our
> traditional stand-alone dump. In case tha checksum test was ok,
> we call purgatory a second time with parameter "1" which then
> starts kdump.
> 
> Could you please ensure that this mechanism also works after
> your rework.

Hi Michael,

All that logic in in arch dependent portion of s390? If yes, I am not
touching any arch dependent part of s390 yet and only doing implementation
of x86.

Generic changes should be usable by s390 and you should be able to do
same thing there. Though we are still detating whether segment checksum
verification logic should be part of purgatory or core kernel.

Thanks
Vivek

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  reply	other threads:[~2013-11-25 15:36 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
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 [this message]
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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