Re: [PATCH v14 6/6] arm64: Add IMA log information in kimage used for kexec

From: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
To: Mimi Zohar <zohar@linux.ibm.com>,
	bauerman@linux.ibm.com, robh@kernel.org,
	takahiro.akashi@linaro.org, gregkh@linuxfoundation.org,
	will@kernel.org, catalin.marinas@arm.com, mpe@ellerman.id.au
Cc: james.morse@arm.com, sashal@kernel.org, benh@kernel.crashing.org,
	paulus@samba.org, frowand.list@gmail.com,
	vincenzo.frascino@arm.com, mark.rutland@arm.com,
	dmitry.kasatkin@gmail.com, jmorris@namei.org, serge@hallyn.com,
	pasha.tatashin@soleen.com, allison@lohutok.net,
	masahiroy@kernel.org, bhsharma@redhat.com, mbrugger@suse.com,
	hsinyi@chromium.org, tao.li@vivo.com, christophe.leroy@c-s.fr,
	prsriva@linux.microsoft.com, balajib@linux.microsoft.com,
	linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linuxppc-dev@vger.kernel.org
Subject: Re: [PATCH v14 6/6] arm64: Add IMA log information in kimage used for kexec
Date: Tue, 12 Jan 2021 15:54:52 -0800	[thread overview]
Message-ID: <45b60441-eb0d-4c02-6f6c-ea2f02bf1ee3@linux.microsoft.com> (raw)
In-Reply-To: <4fef02cb3b330128e6d5d9bc9aab4d7e603d2945.camel@linux.ibm.com>

On 1/12/21 3:28 PM, Mimi Zohar wrote:
> Hi Lakshmi,
> 
> On Mon, 2021-01-04 at 11:26 -0800, Lakshmi Ramasubramanian wrote:
>> Address and size of the buffer containing the IMA measurement log need
>> to be passed from the current kernel to the next kernel on kexec.
>>
>> Any existing "linux,ima-kexec-buffer" property in the device tree
>> needs to be removed and its corresponding memory reservation in
>> the currently running kernel needs to be freed. The address and
>> size of the current kernel's IMA measurement log need to be added
>> to the device tree's IMA kexec buffer node and memory for the buffer
>> needs to be reserved for the log to be carried over to the next kernel
>> on the kexec call.
>>
>> Add address and size fields to "struct kimage_arch" for ARM64 platform
>> to hold the address and size of the IMA measurement log buffer. Remove
>> any existing "linux,ima-kexec-buffer" property in the device tree and
>> free the corresponding memory reservation in the currently running
>> kernel. Add "linux,ima-kexec-buffer" property to the device tree and
>> reserve the memory for storing the IMA log that needs to be passed from
>> the current kernel to the next one.
>>
>> Update CONFIG_KEXEC_FILE to select CONFIG_HAVE_IMA_KEXEC to indicate
>> that the IMA measurement log information is present in the device tree
>> for ARM64.
> 
> Perhaps for some previous version of this patch set, this patch
> description was appropriate, but for the code below it's kind of
> overkill.
> 

I agree Mimi. Will edit the patch description.

thanks,
  -lakshmi

>>
>> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
>> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
>> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
>> ---
>>   arch/arm64/Kconfig             | 1 +
>>   arch/arm64/include/asm/kexec.h | 5 +++++
>>   2 files changed, 6 insertions(+)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index a6b5b7ef40ae..312b4d5ad232 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -1095,6 +1095,7 @@ config KEXEC
>>   config KEXEC_FILE
>>   	bool "kexec file based system call"
>>   	select KEXEC_CORE
>> +	select HAVE_IMA_KEXEC if IMA
>>   	help
>>   	  This is new version of kexec system call. This system call is
>>   	  file based and takes file descriptors as system call argument
>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>> index d24b527e8c00..2bd19ccb6c43 100644
>> --- a/arch/arm64/include/asm/kexec.h
>> +++ b/arch/arm64/include/asm/kexec.h
>> @@ -100,6 +100,11 @@ struct kimage_arch {
>>   	void *elf_headers;
>>   	unsigned long elf_headers_mem;
>>   	unsigned long elf_headers_sz;
>> +
>> +#ifdef CONFIG_IMA_KEXEC
>> +	phys_addr_t ima_buffer_addr;
>> +	size_t ima_buffer_size;
>> +#endif
>>   };
>>   
>>   extern const struct kexec_file_ops kexec_image_ops;
> 