[PATCH v8 07/17] integrity: restrict INTEGRITY_KEYRING_MACHINE to restrict_link_by_ca

[Darren Kenny]

On Tuesday, 2021-11-23 at 23:41:14 -05, Eric Snowberg wrote:
> Set the restriction check for INTEGRITY_KEYRING_MACHINE keys to
> restrict_link_by_ca.  This will only allow CA keys into the machine
> keyring.
>
> Signed-off-by: Eric Snowberg <eric.snowberg at oracle.com>

Reviewed-by: Darren Kenny <darren.kenny at oracle.com>

> ---
> v1: Initial version
> v2: Added !IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING check so mok
>     keyring gets created even when it isn't enabled
> v3: Rename restrict_link_by_system_trusted_or_ca to restrict_link_by_ca
> v4: removed unnecessary restriction->check set
> v5: Rename to machine keyring
> v6: split line over 80 char (suggested by Mimi)
> v8: Unmodified from v6
> ---
>  security/integrity/digsig.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
> index 910fe29a5037..e7dfc55a7c55 100644
> --- a/security/integrity/digsig.c
> +++ b/security/integrity/digsig.c
> @@ -132,14 +132,18 @@ int __init integrity_init_keyring(const unsigned int id)
>  		goto out;
>  	}
>  
> -	if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
> +	if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING) &&
> +	    id != INTEGRITY_KEYRING_MACHINE)
>  		return 0;
>  
>  	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
>  	if (!restriction)
>  		return -ENOMEM;
>  
> -	restriction->check = restrict_link_to_ima;
> +	if (id == INTEGRITY_KEYRING_MACHINE)
> +		restriction->check = restrict_link_by_ca;
> +	else
> +		restriction->check = restrict_link_to_ima;
>  
>  	/*
>  	 * No additional keys shall be allowed to load into the machine
> -- 
> 2.18.4