whisper: change the whisper message format so as to add the payload size (#15870)

* whisper: message format changed

* whisper: tests fixed

* whisper: style fixes

* whisper: fixed names, fixed failing tests

* whisper: fix merge issue in #15870

Occured while using the github online merge tool. Lesson learned.

* whisper: fix a gofmt error for #15870

whisper/whisperv6/whisper.go

@@ -19,7 +19,6 @@ package whisperv6
 import (
 	"bytes"
 	"crypto/ecdsa"
-	crand "crypto/rand"
 	"crypto/sha256"
 	"fmt"
 	"math"
@@ -444,11 +443,10 @@ func (whisper *Whisper) GetPrivateKey(id string) (*ecdsa.PrivateKey, error) {
 // GenerateSymKey generates a random symmetric key and stores it under id,
 // which is then returned. Will be used in the future for session key exchange.
 func (whisper *Whisper) GenerateSymKey() (string, error) {
-	key := make([]byte, aesKeyLength)
-	_, err := crand.Read(key)
+	key, err := generateSecureRandomData(aesKeyLength)
 	if err != nil {
 		return "", err
-	} else if !validateSymmetricKey(key) {
+	} else if !validateDataIntegrity(key, aesKeyLength) {
 		return "", fmt.Errorf("error in GenerateSymKey: crypto/rand failed to generate random data")
 	}
 
@@ -983,9 +981,16 @@ func validatePrivateKey(k *ecdsa.PrivateKey) bool {
 	return ValidatePublicKey(&k.PublicKey)
 }
 
-// validateSymmetricKey returns false if the key contains all zeros
-func validateSymmetricKey(k []byte) bool {
-	return len(k) > 0 && !containsOnlyZeros(k)
+// validateDataIntegrity returns false if the data have the wrong or contains all zeros,
+// which is the simplest and the most common bug.
+func validateDataIntegrity(k []byte, expectedSize int) bool {
+	if len(k) != expectedSize {
+		return false
+	}
+	if expectedSize > 3 && containsOnlyZeros(k) {
+		return false
+	}
+	return true
 }
 
 // containsOnlyZeros checks if the data contain only zeros.
@@ -1019,12 +1024,11 @@ func BytesToUintBigEndian(b []byte) (res uint64) {
 
 // GenerateRandomID generates a random string, which is then returned to be used as a key id
 func GenerateRandomID() (id string, err error) {
-	buf := make([]byte, keyIDSize)
-	_, err = crand.Read(buf)
+	buf, err := generateSecureRandomData(keyIDSize)
 	if err != nil {
 		return "", err
 	}
-	if !validateSymmetricKey(buf) {
+	if !validateDataIntegrity(buf, keyIDSize) {
 		return "", fmt.Errorf("error in generateRandomID: crypto/rand failed to generate random data")
 	}
 	id = common.Bytes2Hex(buf)