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

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Message-ID: <YleYmZAAnF5aOan3@MiWiFi-R3L-srv>
Date:   Thu, 14 Apr 2022 11:44:25 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Coiby Xu <coxu@...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 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.

Otherwise this looks good to me,

Acked-by: Baoquan He <bhe@...hat.com>

> 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
>