Merge branch 'fix-burntstring' into 'dispatch'

Use random bytes instead of runes for burntString

See merge request !152

user/session.go

@@ -361,13 +361,9 @@ func clearCyclicInt(c *cyclic.Int) {
 
 // FIXME Shouldn't we just be putting pseudorandom bytes in to obscure the mem?
 func burntString(length int) string {
+	b := make([]byte, length)
 
-	var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
-
-	b := make([]rune, length)
-	for i := range b {
-		b[i] = letterRunes[rand.Intn(len(letterRunes))]
-	}
+	rand.Read(b)
 
 	return string(b)
 }

user/session_test.go

@@ -239,3 +239,24 @@ func TestGetPrivKey(t *testing.T) {
 		t.Errorf("Private key is not returned correctly!")
 	}
 }
+
+func TestBruntString(t *testing.T) {
+	// Generate a new user and record the pointer to the nick
+	u := new(User)
+	u.Nick = "Mario"
+	preBurnPointer := &u.Nick
+
+	// Burn the string and record the pointer to the nick
+	u.Nick = burntString(len(u.Nick))
+	postBurnPointer := &u.Nick
+
+	// Check the nick is not the same as before
+	if u.Nick == "Mario" {
+		t.Errorf("String was not burnt")
+	}
+
+	// Check the pointer is the same (otherwise it wasn't overwritten)
+	if preBurnPointer != postBurnPointer {
+		t.Errorf("Pointer values are not the same")
+	}
+}
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