Re: [PATCH 2/2 v2] efi: print appropriate status message when loading certificates

[Mimi Zohar]

On Sun, 2019-03-24 at 08:26 +0800, Lee, Chun-Yi 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
> 
> So, this patch shows the status string instead of status code.
> 
> On the other hand, the "Couldn't get UEFI" message doesn't need
> to be exposed when db/dbx/mok variable do not exist. So, this
> patch set the message level to debug.
> 
> v2.
> Setting the MODSIGN messagse level to debug.
> 
> 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 | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
> index 81b19c52832b..e65244b31f04 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;
>  	}
>  
> @@ -155,7 +158,7 @@ static int __init load_uefi_certs(void)
>  	if (!uefi_check_ignore_db()) {
>  		db = get_cert_list(L"db", &secure_var, &dbsize);
>  		if (!db) {
> -			pr_err("MODSIGN: Couldn't get UEFI db list\n");
> +			pr_debug("MODSIGN: Couldn't get UEFI db list\n");

Sure, this is fine.

>  		} else {
>  			rc = parse_efi_signature_list("UEFI:db",
>  					db, dbsize, get_handler_for_db);
> @@ -168,7 +171,7 @@ static int __init load_uefi_certs(void)
>  
>  	mok = get_cert_list(L"MokListRT", &mok_var, &moksize);
>  	if (!mok) {
> -		pr_info("Couldn't get UEFI MokListRT\n");
> +		pr_debug("Couldn't get UEFI MokListRT\n");

This is fine too.

>  	} else {
>  		rc = parse_efi_signature_list("UEFI:MokListRT",
>  					      mok, moksize, get_handler_for_db);
> @@ -179,7 +182,7 @@ static int __init load_uefi_certs(void)
>  
>  	dbx = get_cert_list(L"dbx", &secure_var, &dbxsize);
>  	if (!dbx) {
> -		pr_info("Couldn't get UEFI dbx list\n");
> +		pr_debug("Couldn't get UEFI dbx list\n");

If there isn't a db or moklist, then this is fine. ÂMy concern is not
having an indication that the dbx wasn't installed, when it should
have been.

Perhaps similar to the "Loading compiled-in X.509 certificates"
informational message there should informational messages for db, mok,
and dbx as well.

Mimi


>  	} else {
>  		rc = parse_efi_signature_list("UEFI:dbx",
>  					      dbx, dbxsize,