--- zzzz-none-000/linux-3.10.107/crypto/asymmetric_keys/signature.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/crypto/asymmetric_keys/signature.c	2021-02-04 17:41:59.000000000 +0000
@@ -11,6 +11,7 @@
  * 2 of the Licence, or (at your option) any later version.
  */
 
+#define pr_fmt(fmt) "SIG: "fmt
 #include <keys/asymmetric-subtype.h>
 #include <linux/module.h>
 #include <linux/err.h>
@@ -36,7 +37,7 @@
 		return -EINVAL;
 	subtype = asymmetric_key_subtype(key);
 	if (!subtype ||
-	    !key->payload.data)
+	    !key->payload.data[0])
 		return -EINVAL;
 	if (!subtype->verify_signature)
 		return -ENOTSUPP;