efi_loader: efi_variable_parse_signature() returns NULL on error

Heinrich Schuchardt
2020-05-07T13:53:29Z

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@blueri.se>
>
> Reviewed-by: AKASHI Takahiro <takahiro.akashi@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;
>> }
>>