linux-kernel - Re: [PATCH v12 0/9] ima: kexec: measure events between kexec load and execute

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Message-ID: <4a2f7fde-99ee-4bcd-a97d-fe0db418fd5f@linux.ibm.com>
Date: Wed, 16 Apr 2025 21:09:24 -0400
From: Stefan Berger <stefanb@...ux.ibm.com>
To: steven chen <chenste@...ux.microsoft.com>, zohar@...ux.ibm.com,
        roberto.sassu@...weicloud.com, roberto.sassu@...wei.com,
        eric.snowberg@...cle.com, ebiederm@...ssion.com, paul@...l-moore.com,
        code@...icks.com, bauermann@...abnow.com,
        linux-integrity@...r.kernel.org, kexec@...ts.infradead.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: madvenka@...ux.microsoft.com, nramas@...ux.microsoft.com,
        James.Bottomley@...senPartnership.com, bhe@...hat.com,
        vgoyal@...hat.com, dyoung@...hat.com
Subject: Re: [PATCH v12 0/9] ima: kexec: measure events between kexec load and
 execute



On 4/15/25 10:10 PM, steven chen wrote:
> From: Steven Chen <chenste@...ux.microsoft.com>
> 
> 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'.
> 
> Currently, the kernel behavior during kexec load is to fetch the IMA
> measurements log from TPM PCRs and store it in a buffer. When a kexec
> reboot is triggered, this stored log buffer is carried over to the second
> kernel. However, the time gap between kexec load and kexec reboot can be
> very long. During this time window, new events extended into TPM PCRs miss
> the chance to be carried over to the second kernel. This results in
> mismatch between TPM PCR quotes and the actual IMA measurements list after
> kexec soft reboot, which in turn results in remote attestation failure.

Tested-by: Stefan Berger <stefanb@...ux.ibm.com> # ppc64/kvm