From: ebiederm@xmission.com (Eric W. Biederman)
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Roberto Sassu <roberto.sassu@polito.it>,
Dmitry Kasatkin <dmitry.kasatkin@intel.com>,
Kees Cook <keescook@chromium.org>,
Peter Jones <pjones@redhat.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
kexec@lists.infradead.org,
linux kernel mailing list <linux-kernel@vger.kernel.org>,
horms@verge.net.au, "H. Peter Anvin" <hpa@zytor.com>,
Matthew Garrett <mjg@redhat.com>, Dave Young <dyoung@redhat.com>,
Khalid Aziz <khalid@gonehiking.org>
Subject: Re: Kdump with signed images
Date: Thu, 08 Nov 2012 13:03:17 -0800 [thread overview]
Message-ID: <87vcdfn6y2.fsf@xmission.com> (raw)
In-Reply-To: <20121108194522.GC27586@redhat.com> (Vivek Goyal's message of "Thu, 8 Nov 2012 14:45:22 -0500")
Vivek Goyal <vgoyal@redhat.com> writes:
> On Thu, Nov 08, 2012 at 02:40:50PM -0500, Vivek Goyal wrote:
>> On Tue, Nov 06, 2012 at 03:51:59PM -0800, Eric W. Biederman wrote:
>>
>> [..]
>>
>> Thnking more about executable signature verification, I have another question.
>>
>> While verifyign the signature, we will have to read the whole executable
>> in memory. That sounds bad as we are in kernel mode and will not be killed
>> and if sombody is trying to execute a malformed exceptionally large
>> executable, system will start killing other processess. We can potentially
>> lock all the memory in kernel just by trying to execute a signed huge
>> executable. Not good.
>>
>
> Also, even if we try to read in whole executable, can't an hacker modify
> pages in swap disk and then they will be faulted back in and bingo hacker
> is running its unsigned code. (assuming root has been compromised otherwise
> why do we have to do all this exercise).
You make a decent case for an implicit mlockall(MCL_FUTURE) being
required of signed executables, that are going to be granted privileges
based on signature verification.
As for size if the executable won't fit in memory, there is no point in
checking the signature.
It should be fairly straight forward to make the signature checking
process preemptable and killable.
Of course this is all hand waving at this point.
Eric
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next prev parent reply other threads:[~2012-11-08 21:03 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-18 3:10 [PATCH v2] kdump: pass acpi_rsdp= to 2nd kernel for efi booting Dave Young
2012-10-18 14:56 ` Khalid Aziz
2012-10-18 19:11 ` Vivek Goyal
2012-10-18 19:22 ` Khalid Aziz
2012-10-18 19:38 ` [RFC] Kdump with UEFI secure boot (Re: [PATCH v2] kdump: pass acpi_rsdp= to 2nd kernel for efi booting) Vivek Goyal
2012-10-18 19:55 ` Matthew Garrett
2012-10-18 22:25 ` Eric W. Biederman
2012-10-19 2:06 ` Vivek Goyal
2012-10-19 3:36 ` Eric W. Biederman
2012-10-19 14:31 ` Vivek Goyal
2012-10-22 20:43 ` Vivek Goyal
2012-10-22 21:11 ` Eric W. Biederman
2012-10-23 2:04 ` Simon Horman
2012-10-23 13:24 ` Vivek Goyal
2012-10-23 16:26 ` [RFC] Kdump with signed images Eric W. Biederman
2012-10-23 17:39 ` Vivek Goyal
2012-10-23 19:11 ` Maxim Uvarov
2012-10-23 19:16 ` Vivek Goyal
2012-10-22 21:07 ` [RFC] Kdump with UEFI secure boot (Re: [PATCH v2] kdump: pass acpi_rsdp= to 2nd kernel for efi booting) Eric W. Biederman
2012-10-23 13:18 ` Vivek Goyal
2012-10-23 14:59 ` Vivek Goyal
2012-10-23 15:41 ` Matthew Garrett
2012-10-23 16:44 ` [RFC] Kdump with signed images Eric W. Biederman
2012-10-23 16:52 ` Matthew Garrett
2012-10-24 17:19 ` 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
2012-10-23 16:19 ` Kdump with signed images Eric W. Biederman
2012-10-23 16:31 ` Matthew Garrett
2012-10-23 17:03 ` Eric W. Biederman
2012-10-23 17:09 ` Matthew Garrett
2012-10-24 17:36 ` 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
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 [this message]
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
2012-10-23 15:51 ` [RFC] Kdump with UEFI secure boot (Re: [PATCH v2] kdump: pass acpi_rsdp= to 2nd kernel for efi booting) Eric W. Biederman
2012-10-23 17:18 ` Vivek Goyal
2012-10-19 17:53 ` Vivek Goyal
2012-10-22 21:15 ` Eric W. Biederman
2012-11-02 21:36 ` H. Peter Anvin
2012-11-05 18:11 ` Vivek Goyal
2012-11-05 19:54 ` Eric W. Biederman
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