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From: Mimi Zohar <zohar@linux.ibm.com>
To: Tushar Sugandhi <tusharsu@linux.microsoft.com>,
	ebiederm@xmission.com, noodles@fb.com, bauermann@kolabnow.com,
	kexec@lists.infradead.org, linux-integrity@vger.kernel.org
Cc: code@tyhicks.com, nramas@linux.microsoft.com, paul@paul-moore.com
Subject: Re: [PATCH v2 0/7] ima: kexec: measure events between kexec load and execute
Date: Fri, 27 Oct 2023 15:51:00 -0400	[thread overview]
Message-ID: <348e6e3ebd1c6ee1c85cd12f15591f32bb699fdc.camel@linux.ibm.com> (raw)
In-Reply-To: <8f87e7e4fe5c5a24cdc0d3e2267eeaf00825d1bb.camel@linux.ibm.com>

On Fri, 2023-10-27 at 11:18 -0400, Mimi Zohar wrote:
> On Thu, 2023-10-05 at 11:25 -0700, Tushar Sugandhi wrote:
> > The current Kernel behavior is IMA measurements snapshot is taken at
> > kexec 'load' and not at kexec 'execute'.  IMA log is then carried
> > over to the new Kernel after kexec 'execute'.
> > 
> > Some systems can be configured to call kexec 'load' first, and followed
> > by kexec 'execute' after some time.  (as opposed to calling 'load' and
> > 'execute' in one single kexec command).
> 
> Additional measurements may be introduced by the kexec load itself. 
> Saving the measurement list as close as possible to the reboot is
> beneficial, whether or not the kexec load and kexec execute are
> executed separately.
> 
> > In such scenario, if new IMA
> > measurements are added between kexec 'load' and kexec 'execute', the
> > TPM PCRs are extended with the IMA events between 'load' and 'execute'.
> > But those IMA events are not carried over to the new Kernel after kexec
> > soft reboot.  This results in mismatch between TPM PCR quotes, and the
> > actual IMA measurements list, after the system boots into the new kexec
> > image.  This mismatch results in the remote attestation failing for that
> > system.
> > 
> > This patch series proposes a solution to solve this problem by allocating
> > the necessary buffer at kexec 'load' time, and populating the buffer
> > with the IMA measurements at kexec 'execute' time. 
> 
> How about beginning the paragraph with "To solve this problem allocate
> ... and populate ..."

Does this patch set take into account kexec_calculate_store_digests(),
which is called from kexec_load, and verify_sha256_digest()?
-- 
thanks,

Mimi


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  parent reply	other threads:[~2023-10-27 19:51 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-05 18:25 [PATCH v2 0/7] ima: kexec: measure events between kexec load and execute Tushar Sugandhi
2023-10-05 18:25 ` [PATCH v2 1/7] ima: refactor ima_dump_measurement_list to move memory allocation to a separate function Tushar Sugandhi
2023-10-13  0:28   ` Stefan Berger
2023-10-20 20:33     ` Tushar Sugandhi
2023-10-20 21:21       ` Stefan Berger
2023-10-20 21:50         ` Tushar Sugandhi
2023-10-26 20:16   ` Mimi Zohar
2023-10-27  3:25     ` Mimi Zohar
2023-11-14 22:32       ` Tushar Sugandhi
2023-11-14 22:31     ` Tushar Sugandhi
2023-10-05 18:25 ` [PATCH v2 2/7] ima: move ima_dump_measurement_list call from kexec load to execute Tushar Sugandhi
2023-10-13  0:28   ` Stefan Berger
2023-10-20 20:35     ` Tushar Sugandhi
     [not found]   ` <989af3e9a8621f57643b67b717d9a39fdb2ffe24.camel@linux.ibm.com>
2023-11-14 22:43     ` Tushar Sugandhi
2023-11-15 22:30       ` Tushar Sugandhi
2023-10-05 18:25 ` [PATCH v2 3/7] ima: kexec: map source pages containing IMA buffer to image post kexec load Tushar Sugandhi
2023-10-13  0:29   ` Stefan Berger
2023-10-20 20:36     ` Tushar Sugandhi
2023-10-05 18:25 ` [PATCH v2 4/7] kexec: update kexec_file_load syscall to call ima_kexec_post_load Tushar Sugandhi
2023-10-05 18:26 ` [PATCH v2 5/7] ima: suspend measurements while the buffer is being copied during kexec reboot Tushar Sugandhi
2023-10-05 18:26 ` [PATCH v2 6/7] ima: make the memory for events between kexec load and exec configurable Tushar Sugandhi
2023-10-13  0:27   ` Stefan Berger
2023-10-20 20:39     ` Tushar Sugandhi
2023-10-20 21:16       ` Stefan Berger
2023-10-20 21:53         ` Tushar Sugandhi
2023-10-05 18:26 ` [PATCH v2 7/7] ima: record log size at kexec load and execute Tushar Sugandhi
2023-10-13  0:27   ` Stefan Berger
2023-10-20 20:40     ` Tushar Sugandhi
     [not found]   ` <2b95e8b9ebe10a24c7cb6fc90cb2d1342a157ed5.camel@linux.ibm.com>
2023-11-14 22:48     ` Tushar Sugandhi
     [not found] ` <8f87e7e4fe5c5a24cdc0d3e2267eeaf00825d1bb.camel@linux.ibm.com>
2023-10-27 19:51   ` Mimi Zohar [this message]
2023-11-15 19:21     ` [PATCH v2 0/7] ima: kexec: measure events between " Tushar Sugandhi
2023-11-14 23:24   ` Tushar Sugandhi

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