old_hmac_encode: check for NULL result when allocating *pder

Signed-off-by: NKurt Roeckx <kurt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/hmac/hm_ameth.c

@@ -123,6 +123,8 @@ static int old_hmac_encode(const EVP_PKEY *pkey, unsigned char **pder)
 		if (!*pder)
 			{
 			*pder = OPENSSL_malloc(os->length);
+			if (*pder == NULL)
+				return -1;
 			inc = 0;
 			}
 		else inc = 1;