[2/3] integrity: Move import of MokListRT certs to a separate routine

Move the loading of certs from the UEFI MokListRT into a separate
routine to facilitate additional MokList functionality.

There is no visible functional change as a result of this patch.
Although the UEFI dbx certs are now loaded before the MokList certs,
they are loaded onto different key rings. So the order of the keys
on their respective key rings is the same.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
---
 security/integrity/platform_certs/load_uefi.c | 63 +++++++++++++------
 1 file changed, 44 insertions(+), 19 deletions(-)

On Tue, 2020-08-25 at 23:44 -0400, Lenny Szubowicz wrote:
> Move the loading of certs from the UEFI MokListRT into a separate
> routine to facilitate additional MokList functionality.
> 
> There is no visible functional change as a result of this patch.
> Although the UEFI dbx certs are now loaded before the MokList certs,
> they are loaded onto different key rings. So the order of the keys
> on their respective key rings is the same.
> 
> Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>

Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>

On 9/2/20 3:55 AM, Andy Shevchenko wrote:
> On Wed, Aug 26, 2020 at 6:45 AM Lenny Szubowicz <lszubowi@redhat.com> wrote:
>>
>> Move the loading of certs from the UEFI MokListRT into a separate
>> routine to facilitate additional MokList functionality.
>>
>> There is no visible functional change as a result of this patch.
>> Although the UEFI dbx certs are now loaded before the MokList certs,
>> they are loaded onto different key rings. So the order of the keys
>> on their respective key rings is the same.
> 
> ...
> 
>>   /*
>> + * load_moklist_certs() - Load MokList certs
>> + *
>> + * Returns:    Summary error status
>> + *
>> + * Load the certs contained in the UEFI MokListRT database into the
>> + * platform trusted keyring.
>> + */
> 
> Hmm... Is it intentionally kept out of kernel doc format?

Yes. Since this is a static local routine, I thought that it
shouldn't be included by kerneldoc. But I wanted to generally adhere
to the kernel doc conventions for a routine header. To that end,
in V2 I move the "Return:" section to come after the short description.

> 
>> +static int __init load_moklist_certs(void)
>> +{
>> +       efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
>> +       void *mok = NULL;
>> +       unsigned long moksize = 0;
>> +       efi_status_t status;
>> +       int rc = 0;
> 
> Redundant assignment (see below).
> 
>> +       /* Get MokListRT. It might not exist, so it isn't an error
>> +        * if we can't get it.
>> +        */
>> +       mok = get_cert_list(L"MokListRT", &mok_var, &moksize, &status);
> 
>> +       if (!mok) {
> 
> Why not positive conditional? Sometimes ! is hard to notice.
> 
>> +               if (status == EFI_NOT_FOUND)
>> +                       pr_debug("MokListRT variable wasn't found\n");
>> +               else
>> +                       pr_info("Couldn't get UEFI MokListRT\n");
>> +       } else {
>> +               rc = parse_efi_signature_list("UEFI:MokListRT",
>> +                                             mok, moksize, get_handler_for_db);
>> +               if (rc)
>> +                       pr_err("Couldn't parse MokListRT signatures: %d\n", rc);
>> +               kfree(mok);
> 
>   kfree(...)
>   if (rc)
>    ...
>   return rc;
> 
> And with positive conditional there will be no need to have redundant
> 'else' followed by additional level of indentation.
> 
>> +       }
> 
>> +       return rc;
> 
> return 0;
> 
>> +}
> 
> P.S. Yes, I see that the above was in the original code, so, consider
> my comments as suggestions to improve the code.
> 

I agree that your suggestions improve the code. I've incorporated this
into V2.

                        -Lenny.