Save username only if/when saving auth password

- Currently username is always saved. This changes that to save
  username only when auth password is saved.
- Usernames saved by previous versions are automatically migrated
  if password is also saved, else cleared, to enforce the new behaviour.
- Username and password are saved as encrypted by DPAPI.

Note: Setups in which saving of password is not enabled, any previously
saved username will be forgotten. However, the migration or clearing of
username is attempted only when a connection is started. So previously
saved usernames may stay in the store if a config is unused.

Signed-off-by: Selva Nair <selva.nair@gmail.com>

openvpn.c

@@ -511,6 +511,7 @@ UserAuthDialogFunc(HWND hwndDlg, UINT msg, WPARAM wParam, LPARAM lParam)
             else
             {
                 DeleteSavedAuthPass(param->c->config_name);
+                DeleteSavedUsername(param->c->config_name);
                 Button_SetCheck(GetDlgItem (hwndDlg, ID_CHK_SAVE_PASS), BST_UNCHECKED);
             }
             AutoCloseCancel(hwndDlg); /* user interrupt */
@@ -524,7 +525,6 @@ UserAuthDialogFunc(HWND hwndDlg, UINT msg, WPARAM wParam, LPARAM lParam)
                     show_error_tip(GetDlgItem(hwndDlg, ID_EDT_AUTH_USER), LoadLocalizedString(IDS_ERR_INVALID_USERNAME_INPUT));
                     return 0;
                 }
-                SaveUsername(param->c->config_name, username);
             }
             if (GetDlgItemTextW(hwndDlg, ID_EDT_AUTH_PASS, password, _countof(password)))
             {
@@ -536,6 +536,7 @@ UserAuthDialogFunc(HWND hwndDlg, UINT msg, WPARAM wParam, LPARAM lParam)
                 }
                 if ( param->c->flags & FLAG_SAVE_AUTH_PASS && wcslen(password) )
                 {
+                    SaveUsername(param->c->config_name, username);
                     SaveAuthPass(param->c->config_name, password);
                 }
                 SecureZeroMemory(password, sizeof(password));

save_pass.c

@@ -200,9 +200,7 @@ RecallAuthPass(const WCHAR *config_name, WCHAR *password)
 int
 SaveUsername(const WCHAR *config_name, const WCHAR *username)
 {
-    DWORD len = (wcslen(username) + 1) * sizeof(*username);
-    SetConfigRegistryValueBinary(config_name, AUTH_USER_DATA,(BYTE *) username, len);
-    return 1;
+    return save_encrypted(config_name, username, AUTH_USER_DATA);
 }
 /*
  * The buffer username should be have space for up to USER_PASS_LEN
@@ -212,13 +210,29 @@ int
 RecallUsername(const WCHAR *config_name, WCHAR *username)
 {
     DWORD capacity = USER_PASS_LEN * sizeof(WCHAR);
-    DWORD len;
-
-    len = GetConfigRegistryValue(config_name, AUTH_USER_DATA, (BYTE *) username,  capacity);
-    if (len == 0)
-        return 0;
-    username[USER_PASS_LEN-1] = L'\0';
-    return 1;
+    int retval;
+    retval = recall_encrypted(config_name, username, USER_PASS_LEN, AUTH_USER_DATA);
+    /* older versions saved username unencrypted -- try to read as plain text and migrate */
+    if (!retval)
+    {
+        DWORD len = GetConfigRegistryValue(config_name, AUTH_USER_DATA, (BYTE *) username,  capacity);
+        username[USER_PASS_LEN-1] = L'\0';
+        if (len > 0)
+        {
+            retval = 1;
+            /* re-save as encrypted or delete depending on password is saved or not */
+            if (IsAuthPassSaved(config_name))
+            {
+                SaveUsername(config_name, username); /* overwrites previous plain text value */
+            }
+            else
+            {
+                DeleteSavedUsername(config_name);
+                SecureZeroMemory(username, capacity);
+            }
+        }
+    }
+    return retval;
 }
 
 void
@@ -233,6 +247,12 @@ DeleteSavedAuthPass(const WCHAR *config_name)
     DeleteConfigRegistryValue(config_name, AUTH_PASS_DATA);
 }
 
+void
+DeleteSavedUsername(const WCHAR *config_name)
+{
+    DeleteConfigRegistryValue(config_name, AUTH_USER_DATA);
+}
+
 /* delete saved config-specific auth password and private key passphrase */
 void
 DeleteSavedPasswords(const WCHAR *config_name)
@@ -240,6 +260,7 @@ DeleteSavedPasswords(const WCHAR *config_name)
     DeleteConfigRegistryValue(config_name, KEY_PASS_DATA);
     DeleteConfigRegistryValue(config_name, AUTH_PASS_DATA);
     DeleteConfigRegistryValue(config_name, ENTROPY_DATA);
+    DeleteConfigRegistryValue(config_name, AUTH_USER_DATA);
 }
 
 /* check if auth password is saved */

save_pass.h

@@ -14,6 +14,7 @@ int RecallKeyPass(const WCHAR *config_name, WCHAR *password);
 int RecallAuthPass(const WCHAR *config_name, WCHAR *password);
 int RecallUsername(const WCHAR *config_name, WCHAR *username);
 
+void DeleteSavedUsername(const WCHAR *config_name);
 void DeleteSavedAuthPass(const WCHAR *config_name);
 void DeleteSavedKeyPass(const WCHAR *config_name);
 void DeleteSavedPasswords(const WCHAR *config_name);