Re: [PATCH v5 2/3] kexec, KEYS: make the code in bzImage64_verify_sig generic

From: Coiby Xu <coxu@redhat.com>
To: "Michal Suchánek" <msuchanek@suse.de>
Cc: kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
	Baoquan He <bhe@redhat.com>, Dave Young <dyoung@redhat.com>,
	Will Deacon <will@kernel.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 2/3] kexec, KEYS: make the code in bzImage64_verify_sig generic
Date: Thu, 14 Apr 2022 09:46:05 +0800	[thread overview]
Message-ID: <20220414014605.etdihzqs764v74gf@Rk> (raw)
In-Reply-To: <20220411085411.GZ163591@kunlun.suse.cz>

On Mon, Apr 11, 2022 at 10:54:11AM +0200, Michal Suchánek wrote:
>On Fri, Apr 01, 2022 at 09:31:17AM +0800, Coiby Xu wrote:
>> The code in bzImage64_verify_sig could make use of system keyrings
>s/could make/makes/
>> including .buitin_trusted_keys, .secondary_trusted_keys and .platform
>> keyring to verify signed kernel image as PE file. Make it generic so
>> both x86_64 and arm64 can use it.
>>
>> Signed-off-by: Coiby Xu <coxu@redhat.com>
>> ---
>>  arch/x86/kernel/kexec-bzimage64.c | 13 +------------
>>  include/linux/kexec.h             |  7 +++++++
>>  kernel/kexec_file.c               | 17 +++++++++++++++++
>>  3 files changed, 25 insertions(+), 12 deletions(-)
>>
>> diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
>> index 170d0fd68b1f..f73aab3fde33 100644
>> --- a/arch/x86/kernel/kexec-bzimage64.c
>> +++ b/arch/x86/kernel/kexec-bzimage64.c
>> @@ -17,7 +17,6 @@
>>  #include <linux/kernel.h>
>>  #include <linux/mm.h>
>>  #include <linux/efi.h>
>> -#include <linux/verification.h>
>>
>>  #include <asm/bootparam.h>
>>  #include <asm/setup.h>
>> @@ -531,17 +530,7 @@ static int bzImage64_cleanup(void *loader_data)
>>  #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
>>  static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
>>  {
>> -	int ret;
>> -
>> -	ret = verify_pefile_signature(kernel, kernel_len,
>> -				      VERIFY_USE_SECONDARY_KEYRING,
>> -				      VERIFYING_KEXEC_PE_SIGNATURE);
>> -	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
>> -		ret = verify_pefile_signature(kernel, kernel_len,
>> -					      VERIFY_USE_PLATFORM_KEYRING,
>> -					      VERIFYING_KEXEC_PE_SIGNATURE);
>> -	}
>> -	return ret;
>> +	return kexec_kernel_verify_pe_sig(kernel, kernel_len);
>>  }
>
>Maybe you can completely eliminate bzImage64_verify_sig and directly
>assign kexec_kernel_verify_pe_sig to the fops?
>
>Other than that
>
>Reviewed-by: Michal Suchanek <msuchanek@suse.de>

Applied, thanks for the suggestion and reviewing the patch!

>

>>  #endif
>>
>> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>> index 755fed183224..2fe39e946988 100644
>> --- a/include/linux/kexec.h
>> +++ b/include/linux/kexec.h
>> @@ -19,6 +19,7 @@
>>  #include <asm/io.h>
>>
>>  #include <uapi/linux/kexec.h>
>> +#include <linux/verification.h>
>>
>>  #ifdef CONFIG_KEXEC_CORE
>>  #include <linux/list.h>
>> @@ -196,6 +197,12 @@ int arch_kexec_apply_relocations(struct purgatory_info *pi,
>>  				 const Elf_Shdr *relsec,
>>  				 const Elf_Shdr *symtab);
>>  int arch_kimage_file_post_load_cleanup(struct kimage *image);
>> +#ifdef CONFIG_KEXEC_SIG
>> +#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
>> +int kexec_kernel_verify_pe_sig(const char *kernel,
>> +				    unsigned long kernel_len);
>> +#endif
>> +#endif
>>  int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
>>
>>  extern int kexec_add_buffer(struct kexec_buf *kbuf);
>> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>> index 3720435807eb..754885b96aab 100644
>> --- a/kernel/kexec_file.c
>> +++ b/kernel/kexec_file.c
>> @@ -165,6 +165,23 @@ void kimage_file_post_load_cleanup(struct kimage *image)
>>  }
>>
>>  #ifdef CONFIG_KEXEC_SIG
>> +#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
>> +int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
>> +{
>> +	int ret;
>> +
>> +	ret = verify_pefile_signature(kernel, kernel_len,
>> +				      VERIFY_USE_SECONDARY_KEYRING,
>> +				      VERIFYING_KEXEC_PE_SIGNATURE);
>> +	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
>> +		ret = verify_pefile_signature(kernel, kernel_len,
>> +					      VERIFY_USE_PLATFORM_KEYRING,
>> +					      VERIFYING_KEXEC_PE_SIGNATURE);
>> +	}
>> +	return ret;
>> +}
>> +#endif
>> +
>>  static int kexec_image_verify_sig(struct kimage *image, void *buf,
>>  		unsigned long buf_len)
>>  {
>> --
>> 2.34.1
>>
>

-- 
Best regards,
Coiby

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