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From: Baoquan He <bhe@redhat.com>
To: Mimi Zohar <zohar@linux.ibm.com>
Cc: Jonathan McDowell <noodles@fb.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
	James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>
Subject: Re: [PATCH v5] x86/kexec: Carry forward IMA measurement log on kexec
Date: Thu, 16 Jun 2022 10:59:27 +0800	[thread overview]
Message-ID: <Yqqcj0/j+fC6/K5v@MiWiFi-R3L-srv> (raw)
In-Reply-To: <60813f86e960d12ed3738531a14382769a061a02.camel@linux.ibm.com>

On 06/13/22 at 05:01pm, Mimi Zohar wrote:
> On Mon, 2022-06-13 at 10:30 +0000, Jonathan McDowell wrote:
> > On kexec file load Integrity Measurement Architecture (IMA) subsystem
> > may verify the IMA signature of the kernel and initramfs, and measure
> > it. The command line parameters passed to the kernel in the kexec call
> > may also be measured by IMA. A remote attestation service can verify
> > a TPM quote based on the TPM event log, the IMA measurement list, and
> > the TPM PCR data. This can be achieved only if the IMA measurement log
> > is carried over from the current kernel to the next kernel across
> > the kexec call.
> > 
> > powerpc and ARM64 both achieve this using device tree with a
> > "linux,ima-kexec-buffer" node. x86 platforms generally don't make use of
> > device tree, so use the setup_data mechanism to pass the IMA buffer to
> > the new kernel.
> > 
> > (Mimi, Baoquan, I haven't included your reviewed-bys because this has
> >  changed the compile guards around the ima_(free|get)_kexec_buffer
> >  functions in order to fix the warning the kernel test robot found. I
> >  think this is the right thing to do and avoids us compiling them on
> >  platforms where they won't be used. The alternative would be to drop
> >  the guards in ima.h that Mimi requested for v4.)hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
> > 
> > Signed-off-by: Jonathan McDowell <noodles@fb.com>
> > ---
> > v5:
> >  - Guard ima_(free|get)_kexec_buffer functions with
> >    CONFIG_HAVE_IMA_KEXEC (kernel test robot)
> >  - Use setup_data_offset in setup_boot_parameters and update rather than
> >    calculating in call to setup_ima_state.
> > v4:
> >  - Guard ima.h function prototypes with CONFIG_HAVE_IMA_KEXEC
> 
> > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
> > index 8d374cc552be..42a6c5721a43 100644
> > --- a/drivers/of/kexec.c
> > +++ b/drivers/of/kexec.c
> > @@ -9,6 +9,7 @@
> >   *  Copyright (C) 2016  IBM Corporation
> >   */
> >  
> > +#include <linux/ima.h>
> >  #include <linux/kernel.h>
> >  #include <linux/kexec.h>
> >  #include <linux/memblock.h>
> > @@ -115,6 +116,7 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
> >  	return 0;
> >  }
> >  
> > +#ifdef CONFIG_HAVE_IMA_KEXEC
> >  /**
> >   * ima_get_kexec_buffer - get IMA buffer from the previous kernel
> >   * @addr:	On successful return, set to point to the buffer contents.
> > @@ -173,6 +175,7 @@ int ima_free_kexec_buffer(void)
> >  
> >  	return memblock_phys_free(addr, size);
> >  }
> > +#endif
> 
> Inside ima_{get,free}_kexec_buffer(), there's no need now to test
> whether CONFIG_HAVE_IMA_KEXEC is enabled.
> 
>         if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
>                 return -ENOTSUPP;

Indeed. The #ifdef added by Jonathan is redundant. Not sure if the
original IS_ENABLED(CONFIG_HAVE_IMA_KEXEC) checking inside
ima_{get,free}_kexec_buffer() is intended. I ever reviewed below patch,
the IS_ENABLED(CONFIG_XX) inside static function will make the function
compiled, and will be optimized out if the CONFIG_XX is not enabled.
However, it only has effect on static function. Here,
ima_{get,free}_kexec_buffer() is not static, likely we should remove the
inside IS_ENABLED() checking.

commit 4ece09be9913a87ff99ea347fd7e7adad5bdbc8f
Author: Jisheng Zhang <jszhang@kernel.org>
Date:   Wed Mar 23 16:06:39 2022 -0700

    x86/setup: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
    
    Replace the conditional compilation using "#ifdef CONFIG_KEXEC_CORE" by a
    check for "IS_ENABLED(CONFIG_KEXEC_CORE)", to simplify the code and
    increase compile coverage.

Other than this one Mimi pointed out, this patch looks good to me, thx.

Reviewed-by: Baoquan He <bhe@redhat.com>

> 
> 
> >  
> >  /**
> >   * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
> > diff --git a/include/linux/ima.h b/include/linux/ima.h
> 
> 


WARNING: multiple messages have this Message-ID
From: Baoquan He <bhe@redhat.com>
To: Mimi Zohar <zohar@linux.ibm.com>
Cc: Jonathan McDowell <noodles@fb.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
	James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org"
	<linux-security-module@vger.kernel.org>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>
Subject: Re: [PATCH v5] x86/kexec: Carry forward IMA measurement log on kexec
Date: Thu, 16 Jun 2022 10:59:27 +0800	[thread overview]
Message-ID: <Yqqcj0/j+fC6/K5v@MiWiFi-R3L-srv> (raw)
In-Reply-To: <60813f86e960d12ed3738531a14382769a061a02.camel@linux.ibm.com>

On 06/13/22 at 05:01pm, Mimi Zohar wrote:
> On Mon, 2022-06-13 at 10:30 +0000, Jonathan McDowell wrote:
> > On kexec file load Integrity Measurement Architecture (IMA) subsystem
> > may verify the IMA signature of the kernel and initramfs, and measure
> > it. The command line parameters passed to the kernel in the kexec call
> > may also be measured by IMA. A remote attestation service can verify
> > a TPM quote based on the TPM event log, the IMA measurement list, and
> > the TPM PCR data. This can be achieved only if the IMA measurement log
> > is carried over from the current kernel to the next kernel across
> > the kexec call.
> > 
> > powerpc and ARM64 both achieve this using device tree with a
> > "linux,ima-kexec-buffer" node. x86 platforms generally don't make use of
> > device tree, so use the setup_data mechanism to pass the IMA buffer to
> > the new kernel.
> > 
> > (Mimi, Baoquan, I haven't included your reviewed-bys because this has
> >  changed the compile guards around the ima_(free|get)_kexec_buffer
> >  functions in order to fix the warning the kernel test robot found. I
> >  think this is the right thing to do and avoids us compiling them on
> >  platforms where they won't be used. The alternative would be to drop
> >  the guards in ima.h that Mimi requested for v4.)hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
> > 
> > Signed-off-by: Jonathan McDowell <noodles@fb.com>
> > ---
> > v5:
> >  - Guard ima_(free|get)_kexec_buffer functions with
> >    CONFIG_HAVE_IMA_KEXEC (kernel test robot)
> >  - Use setup_data_offset in setup_boot_parameters and update rather than
> >    calculating in call to setup_ima_state.
> > v4:
> >  - Guard ima.h function prototypes with CONFIG_HAVE_IMA_KEXEC
> 
> > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
> > index 8d374cc552be..42a6c5721a43 100644
> > --- a/drivers/of/kexec.c
> > +++ b/drivers/of/kexec.c
> > @@ -9,6 +9,7 @@
> >   *  Copyright (C) 2016  IBM Corporation
> >   */
> >  
> > +#include <linux/ima.h>
> >  #include <linux/kernel.h>
> >  #include <linux/kexec.h>
> >  #include <linux/memblock.h>
> > @@ -115,6 +116,7 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
> >  	return 0;
> >  }
> >  
> > +#ifdef CONFIG_HAVE_IMA_KEXEC
> >  /**
> >   * ima_get_kexec_buffer - get IMA buffer from the previous kernel
> >   * @addr:	On successful return, set to point to the buffer contents.
> > @@ -173,6 +175,7 @@ int ima_free_kexec_buffer(void)
> >  
> >  	return memblock_phys_free(addr, size);
> >  }
> > +#endif
> 
> Inside ima_{get,free}_kexec_buffer(), there's no need now to test
> whether CONFIG_HAVE_IMA_KEXEC is enabled.
> 
>         if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
>                 return -ENOTSUPP;

Indeed. The #ifdef added by Jonathan is redundant. Not sure if the
original IS_ENABLED(CONFIG_HAVE_IMA_KEXEC) checking inside
ima_{get,free}_kexec_buffer() is intended. I ever reviewed below patch,
the IS_ENABLED(CONFIG_XX) inside static function will make the function
compiled, and will be optimized out if the CONFIG_XX is not enabled.
However, it only has effect on static function. Here,
ima_{get,free}_kexec_buffer() is not static, likely we should remove the
inside IS_ENABLED() checking.

commit 4ece09be9913a87ff99ea347fd7e7adad5bdbc8f
Author: Jisheng Zhang <jszhang@kernel.org>
Date:   Wed Mar 23 16:06:39 2022 -0700

    x86/setup: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
    
    Replace the conditional compilation using "#ifdef CONFIG_KEXEC_CORE" by a
    check for "IS_ENABLED(CONFIG_KEXEC_CORE)", to simplify the code and
    increase compile coverage.

Other than this one Mimi pointed out, this patch looks good to me, thx.

Reviewed-by: Baoquan He <bhe@redhat.com>

> 
> 
> >  
> >  /**
> >   * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
> > diff --git a/include/linux/ima.h b/include/linux/ima.h
> 
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2022-06-16  2:59 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-22 13:50 [PATCH] Carry forward IMA measurement log on kexec on x86_64 Jonathan McDowell
2022-04-25 16:29 ` Mimi Zohar
2022-04-26 12:08   ` Jonathan McDowell
2022-04-26 13:49     ` Mimi Zohar
2022-04-26 16:48       ` Jonathan McDowell
2022-04-26 18:10         ` Mimi Zohar
2022-04-28 10:40           ` Jonathan McDowell
2022-04-28 12:25             ` Mimi Zohar
2022-04-26 16:52 ` [PATCH v2] " Jonathan McDowell
2022-04-29 21:30   ` Mimi Zohar
2022-05-03 12:02     ` Jonathan McDowell
2022-05-04 13:49       ` Mimi Zohar
2022-05-09 10:40   ` Jonathan McDowell
2022-05-09 11:25     ` Boris Petkov
2022-05-09 17:46       ` Jonathan McDowell
2022-05-09 18:09         ` Borislav Petkov
2022-05-09 18:41           ` Jonathan McDowell
2022-05-09 19:40             ` Borislav Petkov
2022-05-10  8:02               ` Jonathan McDowell
2022-05-10 10:46   ` Borislav Petkov
2022-05-11  9:59   ` [PATCH v3] x86/kexec: Carry forward IMA measurement log on kexec Jonathan McDowell
2022-05-11 17:53     ` Mimi Zohar
2022-05-11 17:56       ` Borislav Petkov
2022-05-11 19:12         ` Mimi Zohar
2022-05-12  1:34       ` Mimi Zohar
2022-05-12 16:25     ` [PATCH v4] " Jonathan McDowell
2022-05-13 17:19       ` Lakshmi Ramasubramanian
2022-05-16 15:15         ` Jonathan McDowell
2022-05-17 17:19           ` Lakshmi Ramasubramanian
2022-05-18 10:42             ` Jonathan McDowell
2022-05-18 14:43       ` Mimi Zohar
2022-05-30  8:40         ` Jonathan McDowell
2022-06-03 15:55           ` Dave Hansen
2022-06-03 15:55             ` Dave Hansen
2022-06-06  3:54             ` Baoquan He
2022-06-06  3:54               ` Baoquan He
2022-06-06  4:06       ` Baoquan He
2022-06-10  9:52         ` Jonathan McDowell
2022-06-10  9:52           ` Jonathan McDowell
2022-06-13 10:30       ` [PATCH v5] " Jonathan McDowell
2022-06-13 10:30         ` Jonathan McDowell
2022-06-13 21:01         ` Mimi Zohar
2022-06-13 21:01           ` Mimi Zohar
2022-06-16  2:59           ` Baoquan He [this message]
2022-06-16  2:59             ` Baoquan He
2022-06-16 15:30         ` [PATCH v6] " Jonathan McDowell
2022-06-16 15:30           ` Jonathan McDowell
2022-06-30  8:36           ` [PATCH v7] " Jonathan McDowell
2022-06-30  8:36             ` Jonathan McDowell
2022-06-30 11:54             ` Mimi Zohar
2022-06-30 11:54               ` Mimi Zohar
2022-07-04  2:36             ` Baoquan He
2022-07-04  2:36               ` Baoquan He
2022-06-27 11:56 ` [tip: x86/kdump] " tip-bot2 for Jonathan McDowell
2022-07-01 14:37 ` tip-bot2 for Jonathan McDowell
2022-07-07 16:52 ` [tip: x86/boot] " tip-bot2 for Jonathan McDowell
2022-07-07 17:37   ` Jonathan McDowell
2022-07-07 17:50     ` Dave Hansen

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