Re: [PATCH] ima: Use KEXEC_SIG_FORCE for rejecting unsigned kexec images

[Mimi Zohar <zohar@linux.ibm.com>]

On Wed, 2026-04-15 at 18:23 +0800, Chi Wang wrote:
> From: Chi Wang <wangchi@kylinos.cn>
> 
> Following the split of KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE,
> only KEXEC_SIG_FORCE indicates that unsigned kernel images must be rejected.
> KEXEC_SIG alone enables signature verification but permits unsigned images,
> so it should not trigger the IMA appraisal denial for kexec_load.
> 
> Update the condition in ima_load_data() to check for KEXEC_SIG_FORCE
> instead of KEXEC_SIG.
> 
> Fixes: 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE")
> 
> Signed-off-by: Chi Wang <wangchi@kylinos.cn>

It isn't enough to check whether CONFIG_KEXEC_SIG_FORCE is configured, since it
is possible to require the kexec kernel image to be signed at runtime.  Based on
the IMA policy, IMA will call set_kexec_sig_enforced() to require the kexec
kernel image to be signed.

Mimi

> ---
>  security/integrity/ima/ima_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 1d6229b156fb..ec70e78ab8cd 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -953,7 +953,7 @@ static int ima_load_data(enum kernel_load_data_id id, bool contents)
> 
>  	switch (id) {
>  	case LOADING_KEXEC_IMAGE:
> -		if (IS_ENABLED(CONFIG_KEXEC_SIG)
> +		if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)
>  		    && arch_ima_get_secureboot()) {
>  			pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
>  			return -EACCES;
> --
> 2.25.1