From 86571c7758d48d92f8d1422eca5e2a2e80350587 Mon Sep 17 00:00:00 2001
From: Knut Ahlers <knut@ahlers.me>
Date: Sun, 10 May 2015 19:05:34 +0200
Subject: [PATCH] Fix: Blacklisted characters were not excluded from passwords

---
 lib/generator.go      |  7 ++++++-
 lib/generator_test.go | 22 +++++++++++++++++++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/lib/generator.go b/lib/generator.go
index d32228a..ffb96ee 100644
--- a/lib/generator.go
+++ b/lib/generator.go
@@ -69,9 +69,14 @@ func (s *SecurePassword) GeneratePassword(length int, special bool) (string, err
 	password := ""
 	rand.Seed(time.Now().UnixNano())
 	for {
+		char := string(characterTable[rand.Intn(len(characterTable))])
+		if strings.Contains(strings.Join(s.badCharacters, ""), char) {
+			continue
+		}
+
 		password = fmt.Sprintf("%s%s",
 			password,
-			string(characterTable[rand.Intn(len(characterTable))]),
+			char,
 		)
 		if len(password) == length {
 			if s.CheckPasswordSecurity(password, special) {
diff --git a/lib/generator_test.go b/lib/generator_test.go
index ad731b2..dd72c8c 100644
--- a/lib/generator_test.go
+++ b/lib/generator_test.go
@@ -1,6 +1,9 @@
 package securepassword
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestInsecurePasswords(t *testing.T) {
 	passwords := map[string]string{
@@ -119,6 +122,23 @@ func TestImpossiblePasswords(t *testing.T) {
 	}
 }
 
+func TestBadCharacters(t *testing.T) {
+	badCharacters := []string{"I", "l", "0", "O", "B", "8"}
+
+	for i := 0; i < 500; i++ {
+		pwd, err := NewSecurePassword().GeneratePassword(20, false)
+		if err != nil {
+			t.Errorf("An error occured: %s", err)
+		}
+		for _, char := range badCharacters {
+			if strings.Contains(pwd, char) {
+				t.Errorf("Password '%s' contained blacklisted character: '%s'", pwd, char)
+				return
+			}
+		}
+	}
+}
+
 func BenchmarkGeneratePasswords8Char(b *testing.B) {
 	pwd := NewSecurePassword()
 	for i := 0; i < b.N; i++ {