linux-kernel - Re: [PATCH v13 0/9] ima: kexec: measure events between kexec load and execute

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Message-ID: <aBmizZATrxhXbWyE@MiWiFi-R3L-srv>
Date: Tue, 6 May 2025 13:49:01 +0800
From: Baoquan He <bhe@...hat.com>
To: steven chen <chenste@...ux.microsoft.com>
Cc: zohar@...ux.ibm.com, stefanb@...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,
	madvenka@...ux.microsoft.com, nramas@...ux.microsoft.com,
	James.Bottomley@...senpartnership.com, vgoyal@...hat.com,
	dyoung@...hat.com
Subject: Re: [PATCH v13 0/9] ima: kexec: measure events between kexec load
 and execute

On 05/02/25 at 09:25am, steven chen wrote:
> On 4/24/2025 7:37 AM, Baoquan He wrote:
> > Hi Steven,
> > 
> > Could you test below code and post a formal patch to not copy
> > measurement list buffer to kdump kernel? Below log is just for your
> > reference, please feel free to modify or rephrase.
> > 
> > ===
> > Kdump kernel doesn't need IMA to do integrity measurement.
> > Hence the measurement list in 1st kernel doesn't need to be copied to
> > kdump kenrel.
> > 
> > Here skip allocating buffer for measurement list copying if loading
> > kdump kernel. Then there won't be the later handling related to
> > ima_kexec_buffer.
> > ===
> > 
> > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> > index 38cb2500f4c3..7362f68f2d8b 100644
> > --- a/security/integrity/ima/ima_kexec.c
> > +++ b/security/integrity/ima/ima_kexec.c
> > @@ -146,6 +146,9 @@ void ima_add_kexec_buffer(struct kimage *image)
> >   	void *kexec_buffer = NULL;
> >   	int ret;
> > +	if (image->type == KEXEC_TYPE_CRASH)
> > +		return;
> > +
> >   	/*
> >   	 * Reserve extra memory for measurements added during kexec.
> >   	 */
> > 
> Hi Baoquan,
> 
> I tested the kernel with above change. Normal soft reboot works fine.
> 
> I will post the patch for review.

Just come back from Labor Day public holiday. I went through the code
flow, the code should be fine. I will test it by checking the setup_data
if IMA data is excluded in kdump case.