Add random domain and random email functions

random/random.go

@@ -3,6 +3,9 @@ package random
 import (
 	"crypto/rand"
 	"math/big"
+	"strings"
+
+	"github.com/vulncheck-oss/go-exploit/output"
 )
 
 var (
@@ -16,7 +19,10 @@ func RandIntRange(rangeMin int, rangeMax int) int {
 	rangeMaxBig := big.NewInt(int64(rangeMax) - int64(rangeMin))
 	n, err := rand.Int(rand.Reader, rangeMaxBig)
 	if err != nil {
-		panic(err)
+		// if random fails the process will die anyway: https://github.com/golang/go/issues/66821
+		output.PrintfFrameworkError("Random generation error: %s", err.Error())
+
+		return 0
 	}
 
 	return int(n.Int64() + int64(rangeMin))
@@ -26,7 +32,10 @@ func RandIntRange(rangeMin int, rangeMax int) int {
 func RandPositiveInt(rangeMax int) int {
 	n, err := rand.Int(rand.Reader, big.NewInt(int64(rangeMax)))
 	if err != nil {
-		panic(err)
+		// if random fails the process will die anyway: https://github.com/golang/go/issues/66821
+		output.PrintfFrameworkError("Random generation error: %s", err.Error())
+
+		return 0
 	}
 
 	return int(n.Int64())
@@ -42,7 +51,7 @@ func RandLetters(n int) string {
 	return string(runeSlice)
 }
 
-// RandLetters generates a random alpha string with no bad chars of length n.
+// RandLettersNoBadChars generates a random alpha string with no bad chars of length n.
 // This will return an empty string if the caller badchars all "letters".
 func RandLettersNoBadChars(n int, badchars []rune) string {
 	// rebuild the letters slice without the bad chars. O(n^2) implementation
@@ -111,3 +120,23 @@ func RandDigits(n int) string {
 func RandDigitsRange(rangeMin int, rangeMax int) string {
 	return RandDigits(RandIntRange(rangeMin, rangeMax))
 }
+
+// RandDomain generates a random domain name with a common TLDs. The domain will be between 8 and 14 characters.
+func RandDomain() string {
+	return strings.ToLower(RandLettersRange(4, 10) + "." + CommonTLDs[RandPositiveInt(len(CommonTLDs))])
+}
+
+// RandEmail generates a random email address using common domain TLDs. The largest size of the
+// generated domain will be 23 characters and smallest will be 13 characters. The goal is not to
+// generate a set of RFC valid domains, but simple lower case emails that are valid for most
+// automated account registration or usage, so these might be "too simple" or for some uses.
+func RandEmail() string {
+	return strings.ToLower(RandLettersRange(4, 8) + "@" + RandDomain())
+}
+
+// CommonTLDs contains the 3 most common DNS TLDs.
+var CommonTLDs = []string{
+	"com",
+	"org",
+	"net",
+}

random/random_test.go

@@ -1,6 +1,7 @@
 package random
 
 import (
+	"strings"
 	"testing"
 )
 
@@ -140,3 +141,27 @@ func Test_RandDigitsRange(t *testing.T) {
 		}
 	}
 }
+
+func Test_RandDomain(t *testing.T) {
+	for range 100 {
+		r := RandDomain()
+		if len(r) > 14 || len(r) < 8 {
+			t.Error("Domain generated with an unexpected length: " + r)
+		}
+		if !strings.Contains(r, ".") {
+			t.Error("Domain generated without expected characters: " + r)
+		}
+	}
+}
+
+func Test_RandEmail(t *testing.T) {
+	for range 100 {
+		r := RandEmail()
+		if len(r) > 23 || len(r) < 13 {
+			t.Error("Domain generated with an unexpected length: " + r)
+		}
+		if !strings.Contains(r, ".") {
+			t.Error("Domain generated without expected characters: " + r)
+		}
+	}
+}