efi_loader: efi_variable_parse_signature() returns NULL on error

[Heinrich Schuchardt]

On 07.05.20 09:15, AKASHI Takahiro wrote:
> On Thu, May 07, 2020 at 02:13:18AM +0200, Patrick Wildt wrote:
>> efi_variable_parse_signature() returns NULL on error, so IS_NULL()

IS_NULL() seems to be a typo. I will replace it by IS_ERR() when merging.

>> is an incorrect check.  The goto err leads to pkcs7_free_message(),
>> which works fine on a NULL ptr.
>>
>> Signed-off-by: Patrick Wildt <patrick at blueri.se>
>
> Reviewed-by: AKASHI Takahiro <takahiro.akashi at linaro.org>

Hello Takahiro,

there is a second instance of the same error:

lib/efi_loader/efi_variable.c:412:

        msg = pkcs7_parse_message(ebuf, ebuflen);
        free(ebuf);
out:
        if (IS_ERR(msg))
                return NULL;

Please, send a patch for that one too.

Best regards

Heinrich


>
>>
>> diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
>> index 58f8fae358..c5fe896de2 100644
>> --- a/lib/efi_loader/efi_variable.c
>> +++ b/lib/efi_loader/efi_variable.c
>> @@ -519,9 +519,8 @@ static efi_status_t efi_variable_authenticate(u16 *variable,
>>  	var_sig = efi_variable_parse_signature(auth->auth_info.cert_data,
>>  					       auth->auth_info.hdr.dwLength
>>  						   - sizeof(auth->auth_info));
>> -	if (IS_ERR(var_sig)) {
>> +	if (!var_sig) {
>>  		debug("Parsing variable's signature failed\n");
>> -		var_sig = NULL;
>>  		goto err;
>>  	}
>>