linux-kernel - Re: [PATCH v6 1/4] kexec: clean up arch_kexec_kernel_verify

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Date:   Fri, 15 Apr 2022 17:37:35 +0800
From:   Coiby Xu <coxu@...hat.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     kexec@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
        Michal Suchanek <msuchanek@...e.de>,
        Dave Young <dyoung@...hat.com>, Will Deacon <will@...nel.org>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        Mimi Zohar <zohar@...ux.ibm.com>, Chun-Yi Lee <jlee@...e.com>,
        stable@...nel.org, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 1/4] kexec: clean up arch_kexec_kernel_verify_sig

On Thu, Apr 14, 2022 at 11:44:25AM +0800, Baoquan He wrote:
>On 04/14/22 at 09:43am, Coiby Xu wrote:
>> Currently there is no arch-specific implementation of
>> arch_kexec_kernel_verify_sig. Even if we want to add an implementation
>> for an architecture in the future, we can simply use "(struct
>> kexec_file_ops*)->verify_sig". So clean it up.
>>
>> Suggested-by: Eric W. Biederman <ebiederm@...ssion.com>
>> Cc: stable@...nel.org
>
>It should be not worth noticing stable kernel that a clean up patch need
>be back ported.

Thanks for the suggestion! For the 2nd and 3rd patch, I'll add prerequisite
info,

Cc: stable@...nel.org # 34d5960af253: kexec: clean up arch_kexec_kernel_verify_sig

and 

Cc: stable@...nel.org # 34d5960af253: kexec: clean up arch_kexec_kernel_verify_sig
Cc: stable@...nel.org # 83b7bb2d49ae: kexec, KEYS: make the code in bzImage64_verify_sig generic

respectively.

>
>Otherwise this looks good to me,
>
>Acked-by: Baoquan He <bhe@...hat.com>

Thanks for reviewing the patch!

>
>> Reviewed-by: Michal Suchanek <msuchanek@...e.de>
>> Signed-off-by: Coiby Xu <coxu@...hat.com>
>> ---
>>  include/linux/kexec.h |  4 ----
>>  kernel/kexec_file.c   | 34 +++++++++++++---------------------
>>  2 files changed, 13 insertions(+), 25 deletions(-)
>>
>> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>> index 58d1b58a971e..413235c6c797 100644
>> --- a/include/linux/kexec.h
>> +++ b/include/linux/kexec.h
>> @@ -202,10 +202,6 @@ 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
>> -int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
>> -				 unsigned long buf_len);
>> -#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 8347fc158d2b..3720435807eb 100644
>> --- a/kernel/kexec_file.c
>> +++ b/kernel/kexec_file.c
>> @@ -89,25 +89,6 @@ int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
>>  	return kexec_image_post_load_cleanup_default(image);
>>  }
>>
>> -#ifdef CONFIG_KEXEC_SIG
>> -static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
>> -					  unsigned long buf_len)
>> -{
>> -	if (!image->fops || !image->fops->verify_sig) {
>> -		pr_debug("kernel loader does not support signature verification.\n");
>> -		return -EKEYREJECTED;
>> -	}
>> -
>> -	return image->fops->verify_sig(buf, buf_len);
>> -}
>> -
>> -int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
>> -					unsigned long buf_len)
>> -{
>> -	return kexec_image_verify_sig_default(image, buf, buf_len);
>> -}
>> -#endif
>> -
>>  /*
>>   * arch_kexec_apply_relocations_add - apply relocations of type RELA
>>   * @pi:		Purgatory to be relocated.
>> @@ -184,13 +165,24 @@ void kimage_file_post_load_cleanup(struct kimage *image)
>>  }
>>
>>  #ifdef CONFIG_KEXEC_SIG
>> +static int kexec_image_verify_sig(struct kimage *image, void *buf,
>> +		unsigned long buf_len)
>> +{
>> +	if (!image->fops || !image->fops->verify_sig) {
>> +		pr_debug("kernel loader does not support signature verification.\n");
>> +		return -EKEYREJECTED;
>> +	}
>> +
>> +	return image->fops->verify_sig(buf, buf_len);
>> +}
>> +
>>  static int
>>  kimage_validate_signature(struct kimage *image)
>>  {
>>  	int ret;
>>
>> -	ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
>> -					   image->kernel_buf_len);
>> +	ret = kexec_image_verify_sig(image, image->kernel_buf,
>> +			image->kernel_buf_len);
>>  	if (ret) {
>>
>>  		if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
>> --
>> 2.34.1
>>
>

-- 
Best regards,
Coiby