Re: [PATCH 2/2] efi: print appropriate status message when loading certificates

[Ard Biesheuvel]

On Fri, 22 Mar 2019 at 11:34, Lee, Chun-Yi <joeyli.kernel@xxxxxxxxx> wrote:
>
> When loading certificates list from UEFI variable, the original error
> message direct shows the efi status code from UEFI firmware. It looks
> ugly:
>
> [    2.335031] Couldn't get size: 0x800000000000000e
> [    2.335032] Couldn't get UEFI MokListRT
> [    2.339985] Couldn't get size: 0x800000000000000e
> [    2.339987] Couldn't get UEFI dbx list
>

Why is it an error in the first place if these EFI variables do not exist?


> So, this patch shows the status string instead of status code.
>
> On the other hand, the error message of EFI_NOT_FOUND
> (0x800000000000000e) doesn't need to be exposed because kernel
> already prints "Couldn't get UEFI..." message. This patch also
> filtered out it.
>
> Link: https://forums.opensuse.org/showthread.php/535324-MODSIGN-Couldn-t-get-UEFI-db-list?p=2897516#post2897516
> Cc: James Morris <jmorris@xxxxxxxxx>
> Cc: Serge E. Hallyn" <serge@xxxxxxxxxx>
> Cc: David Howells <dhowells@xxxxxxxxxx>
> Cc: Nayna Jain <nayna@xxxxxxxxxxxxx>
> Cc: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
> Cc: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> Signed-off-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
> ---
>  security/integrity/platform_certs/load_uefi.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
> index 81b19c52832b..fe261166621f 100644
> --- a/security/integrity/platform_certs/load_uefi.c
> +++ b/security/integrity/platform_certs/load_uefi.c
> @@ -48,7 +48,9 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
>
>         status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb);
>         if (status != EFI_BUFFER_TOO_SMALL) {
> -               pr_err("Couldn't get size: 0x%lx\n", status);
> +               if (status != EFI_NOT_FOUND)
> +                       pr_err("Couldn't get size: %s\n",
> +                               efi_status_to_str(status));
>                 return NULL;
>         }
>
> @@ -59,7 +61,8 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
>         status = efi.get_variable(name, guid, NULL, &lsize, db);
>         if (status != EFI_SUCCESS) {
>                 kfree(db);
> -               pr_err("Error reading db var: 0x%lx\n", status);
> +               pr_err("Error reading db var: %s\n",
> +                       efi_status_to_str(status));
>                 return NULL;
>         }
>
> --
> 2.16.4
>