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From: Mimi Zohar <zohar@linux.ibm.com>
To: Tushar Sugandhi <tusharsu@linux.microsoft.com>,
	Paul Moore <paul@paul-moore.com>
Cc: linux-integrity@vger.kernel.org, peterhuewe@gmx.de,
	Jarkko Sakkinen <jarkko@kernel.org>,
	jgg@ziepe.ca, Ken Goldman <kgold@linux.ibm.com>,
	bhe@redhat.com, vgoyal@redhat.com, Dave Young <dyoung@redhat.com>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	jmorris@namei.org, serge@hallyn.com,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	linux-security-module@vger.kernel.org,
	Tyler Hicks <tyhicks@linux.microsoft.com>,
	Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	Sush Shringarputale <sushring@linux.microsoft.com>
Subject: Re: [RFC V2] IMA Log Snapshotting Design Proposal
Date: Tue, 21 Nov 2023 20:18:14 -0500	[thread overview]
Message-ID: <09adb80a9317062a7139527eb0cbd45bb7d78b4f.camel@linux.ibm.com> (raw)
In-Reply-To: <e0cf16b3-514e-45bd-b6f8-7638ed57b00e@linux.microsoft.com>

On Tue, 2023-11-21 at 17:01 -0800, Tushar Sugandhi wrote:
> Hi Mimi,
> To address your concern about pausing the measurements -
> We are not proposing to pause the measurements for the entire duration
> of UM <--> Kernel interaction while taking a snapshot.
> 
> We are simply proposing to pause the measurements when we get the TPM
> PCR quotes to add them to "snapshot_aggregate". (which should be a very
> small time window). IMA already has this mechanism when two separate
> modules try to add entry to IMA log - by using
> mutex_lock(&ima_extend_list_mutex); in ima_add_template_entry.
> 
> 
> We plan to use this existing locking functionality.
> Hope this addresses your concern about pausing extending the measurement
> list.

Each TPM PCR read is a separate TPM command.  Have you done any
performance anlaysis to see how long it actually takes to calculate the
"snapshot_aggregate" with a physical TPM?

The "snapshot_aggregate" is a new critical-data and should be
upstreamed independently of this patch set.

-- 
thanks,

Mimi


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WARNING: multiple messages have this Message-ID (diff)
From: Mimi Zohar <zohar@linux.ibm.com>
To: Tushar Sugandhi <tusharsu@linux.microsoft.com>,
	Paul Moore <paul@paul-moore.com>
Cc: linux-integrity@vger.kernel.org, peterhuewe@gmx.de,
	Jarkko Sakkinen <jarkko@kernel.org>,
	jgg@ziepe.ca, Ken Goldman <kgold@linux.ibm.com>,
	bhe@redhat.com, vgoyal@redhat.com, Dave Young <dyoung@redhat.com>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	jmorris@namei.org, serge@hallyn.com,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	linux-security-module@vger.kernel.org,
	Tyler Hicks <tyhicks@linux.microsoft.com>,
	Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	Sush Shringarputale <sushring@linux.microsoft.com>
Subject: Re: [RFC V2] IMA Log Snapshotting Design Proposal
Date: Tue, 21 Nov 2023 20:18:14 -0500	[thread overview]
Message-ID: <09adb80a9317062a7139527eb0cbd45bb7d78b4f.camel@linux.ibm.com> (raw)
In-Reply-To: <e0cf16b3-514e-45bd-b6f8-7638ed57b00e@linux.microsoft.com>

On Tue, 2023-11-21 at 17:01 -0800, Tushar Sugandhi wrote:
> Hi Mimi,
> To address your concern about pausing the measurements -
> We are not proposing to pause the measurements for the entire duration
> of UM <--> Kernel interaction while taking a snapshot.
> 
> We are simply proposing to pause the measurements when we get the TPM
> PCR quotes to add them to "snapshot_aggregate". (which should be a very
> small time window). IMA already has this mechanism when two separate
> modules try to add entry to IMA log - by using
> mutex_lock(&ima_extend_list_mutex); in ima_add_template_entry.
> 
> 
> We plan to use this existing locking functionality.
> Hope this addresses your concern about pausing extending the measurement
> list.

Each TPM PCR read is a separate TPM command.  Have you done any
performance anlaysis to see how long it actually takes to calculate the
"snapshot_aggregate" with a physical TPM?

The "snapshot_aggregate" is a new critical-data and should be
upstreamed independently of this patch set.

-- 
thanks,

Mimi


  reply	other threads:[~2023-11-22  1:18 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-19 18:49 [RFC V2] IMA Log Snapshotting Design Proposal Tushar Sugandhi
2023-10-19 18:49 ` Tushar Sugandhi
2023-10-31 18:37 ` Ken Goldman
2023-10-31 18:37   ` Ken Goldman
2023-11-13 18:14   ` Sush Shringarputale
2023-11-13 18:14     ` Sush Shringarputale
2023-10-31 19:15 ` Mimi Zohar
2023-10-31 19:15   ` Mimi Zohar
2023-11-16 22:28   ` Paul Moore
2023-11-16 22:28     ` Paul Moore
2023-11-22  1:01     ` Tushar Sugandhi
2023-11-22  1:01       ` Tushar Sugandhi
2023-11-22  1:18       ` Mimi Zohar [this message]
2023-11-22  1:18         ` Mimi Zohar
2023-11-22  4:27     ` Paul Moore
2023-11-22  4:27       ` Paul Moore
2023-11-22 13:18       ` Mimi Zohar
2023-11-22 13:18         ` Mimi Zohar
2023-11-22 14:22         ` Paul Moore
2023-11-22 14:22           ` Paul Moore
2023-11-27 17:07           ` Mimi Zohar
2023-11-27 17:07             ` Mimi Zohar
2023-11-27 22:16             ` Paul Moore
2023-11-27 22:16               ` Paul Moore
2023-11-28 12:09               ` Mimi Zohar
2023-11-28 12:09                 ` Mimi Zohar
2023-11-29  1:06                 ` Paul Moore
2023-11-29  1:06                   ` Paul Moore
2023-11-29  2:07                   ` Mimi Zohar
2023-11-29  2:07                     ` Mimi Zohar
2024-01-06 23:27                     ` Paul Moore
2024-01-06 23:27                       ` Paul Moore
2024-01-07 12:58                       ` Mimi Zohar
2024-01-07 12:58                         ` Mimi Zohar
2024-01-08  2:58                         ` Paul Moore
2024-01-08  2:58                           ` Paul Moore
2024-01-08 11:48                           ` Mimi Zohar
2024-01-08 11:48                             ` Mimi Zohar
2024-01-08 17:15                             ` Paul Moore
2024-01-08 17:15                               ` Paul Moore
2023-12-20 22:13           ` Ken Goldman
2023-12-20 22:13             ` Ken Goldman
2024-01-06 23:44             ` Paul Moore
2024-01-06 23:44               ` Paul Moore
2023-11-13 18:59 ` Stefan Berger
2023-11-13 18:59   ` Stefan Berger
2023-11-14 18:36   ` Sush Shringarputale
2023-11-14 18:36     ` Sush Shringarputale
2023-11-14 18:58     ` Stefan Berger
2023-11-14 18:58       ` Stefan Berger
2023-11-16 22:07       ` Paul Moore
2023-11-16 22:07         ` Paul Moore
2023-11-16 22:41         ` Stefan Berger
2023-11-16 22:41           ` Stefan Berger
2023-11-16 22:56           ` Paul Moore
2023-11-16 22:56             ` Paul Moore
2023-11-17 22:41             ` Sush Shringarputale
2023-11-17 22:41               ` Sush Shringarputale
2023-11-20 20:03         ` Tushar Sugandhi
2023-11-20 20:03           ` Tushar Sugandhi

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