[users] Apply validation to the passwords config knows about

- avoid update loops by checking values before emitting *Changed()
- check validity of user and root passwords when asked
- if root isn't going to be written, or re-uses the user password,
  defer to those status checks.

src/modules/users/Config.cpp

@@ -381,7 +381,7 @@ Config::setRequireStrongPasswords( bool strong )
 }
 
 bool
-Config::isPasswordAcceptable( const QString& password, QString& message )
+Config::isPasswordAcceptable( const QString& password, QString& message ) const
 {
     bool failureIsFatal = requireStrongPasswords();
 
@@ -402,23 +402,58 @@ Config::isPasswordAcceptable( const QString& password, QString& message )
 void
 Config::setUserPassword( const QString& s )
 {
-    m_userPassword = s;
-    // TODO: check new password status
-    emit userPasswordChanged( s );
+    if ( s != m_userPassword )
+    {
+        m_userPassword = s;
+        // TODO: check new password status
+        emit userPasswordChanged( s );
+    }
 }
 
 void
 Config::setUserPasswordSecondary( const QString& s )
 {
-    m_userPasswordSecondary = s;
-    // TODO: check new password status
-    emit userPasswordSecondaryChanged( s );
+    if ( s != m_userPasswordSecondary )
+    {
+        m_userPasswordSecondary = s;
+        // TODO: check new password status
+        emit userPasswordSecondaryChanged( s );
+    }
 }
 
+QPair< Config::PasswordValidity, QString >
+Config::passwordStatus( const QString& pw1, const QString& pw2 ) const
+{
+    if ( pw1 != pw2 )
+    {
+        return qMakePair( PasswordValidity::Invalid, tr( "Your passwords do not match!" ) );
+    }
+
+    QString message;
+    bool ok = isPasswordAcceptable( pw1, message );
+    return qMakePair( ok ? PasswordValidity::Valid : PasswordValidity::Weak, message );
+}
+
+
+int
+Config::userPasswordValidity() const
+{
+    auto p = passwordStatus( m_userPassword, m_userPasswordSecondary );
+    return p.first;
+}
+
+QString
+Config::userPasswordStatus() const
+{
+    auto p = passwordStatus( m_userPassword, m_userPasswordSecondary );
+    return p.second;
+}
+
+
 void
 Config::setRootPassword( const QString& s )
 {
-    if ( writeRootPassword() )
+    if ( writeRootPassword() && s != m_rootPassword )
     {
         m_rootPassword = s;
         // TODO: check new password status
@@ -429,7 +464,7 @@ Config::setRootPassword( const QString& s )
 void
 Config::setRootPasswordSecondary( const QString& s )
 {
-    if ( writeRootPassword() )
+    if ( writeRootPassword() && s != m_rootPasswordSecondary )
     {
         m_rootPasswordSecondary = s;
         // TODO: check new password status
@@ -437,28 +472,62 @@ Config::setRootPasswordSecondary( const QString& s )
     }
 }
 
-QString Config::rootPassword() const
+QString
+Config::rootPassword() const
 {
     if ( writeRootPassword() )
     {
         if ( reuseUserPasswordForRoot() )
+        {
             return userPassword();
+        }
         return m_rootPassword;
     }
     return QString();
 }
 
-QString Config::rootPasswordSecondary() const
+QString
+Config::rootPasswordSecondary() const
 {
     if ( writeRootPassword() )
     {
         if ( reuseUserPasswordForRoot() )
+        {
             return userPasswordSecondary();
+        }
         return m_rootPasswordSecondary;
     }
     return QString();
 }
 
+int
+Config::rootPasswordValidity() const
+{
+    if ( writeRootPassword() && !reuseUserPasswordForRoot() )
+    {
+        auto p = passwordStatus( m_rootPassword, m_rootPasswordSecondary );
+        return p.first;
+    }
+    else
+    {
+        return userPasswordValidity();
+    }
+}
+
+QString
+Config::rootPasswordStatus() const
+{
+    if ( writeRootPassword() && !reuseUserPasswordForRoot() )
+    {
+        auto p = passwordStatus( m_rootPassword, m_rootPasswordSecondary );
+        return p.second;
+    }
+    else
+    {
+        return userPasswordStatus();
+    }
+}
+
 
 STATICTEST void
 setConfigurationDefaultGroups( const QVariantMap& map, QStringList& defaultGroups )

src/modules/users/Config.h

@@ -62,9 +62,14 @@ class Config : public QObject
     Q_PROPERTY( QString userPassword READ userPassword WRITE setUserPassword NOTIFY userPasswordChanged )
     Q_PROPERTY( QString userPasswordSecondary READ userPasswordSecondary WRITE setUserPasswordSecondary NOTIFY
                     userPasswordSecondaryChanged )
+    Q_PROPERTY( int userPasswordValidity READ userPasswordValidity NOTIFY userPasswordStatusChanged STORED false )
+    Q_PROPERTY( QString userPasswordStatus READ userPasswordStatus NOTIFY userPasswordStatusChanged STORED false )
+
     Q_PROPERTY( QString rootPassword READ rootPassword WRITE setRootPassword NOTIFY rootPasswordChanged )
     Q_PROPERTY( QString rootPasswordSecondary READ rootPasswordSecondary WRITE setRootPasswordSecondary NOTIFY
                     rootPasswordSecondaryChanged )
+    Q_PROPERTY( int rootPasswordValidity READ rootPasswordValidity NOTIFY rootPasswordStatusChanged STORED false )
+    Q_PROPERTY( QString rootPasswordStatus READ rootPasswordStatus NOTIFY rootPasswordStatusChanged STORED false )
 
     Q_PROPERTY( bool writeRootPassword READ writeRootPassword CONSTANT )
     Q_PROPERTY( bool reuseUserPasswordForRoot READ reuseUserPasswordForRoot WRITE setReuseUserPasswordForRoot NOTIFY
@@ -75,6 +80,27 @@ class Config : public QObject
                     requireStrongPasswordsChanged )
 
 public:
+    /** @brief Validity (status) of a password
+     *
+     * Valid passwords are:
+     *  - primary and secondary are equal **and**
+     *  - all the password-strength checks pass
+     * Weak passwords:
+     *  - primary and secondary are equal **and**
+     *  - not all the checks pass **and**
+     *  - permitWeakPasswords is @c true **and**
+     *  - requireStrongPasswords is @c false
+     * Invalid passwords (all other cases):
+     *  - the primary and secondary values are not equal **or**
+     *  - not all the checks pass and weak passwords are not permitted
+     */
+    enum PasswordValidity
+    {
+        Valid = 0,
+        Weak = 1,
+        Invalid = 2
+    };
+
     Config( QObject* parent = nullptr );
     ~Config();
 
@@ -128,16 +154,21 @@ public:
      * If the password is not acceptable, sets @p message to something
      *   non-empty and returns @c false.
      */
-    bool isPasswordAcceptable( const QString& password, QString& message );
+    bool isPasswordAcceptable( const QString& password, QString& message ) const;
 
     // The user enters a password (and again in a separate UI element)
     QString userPassword() const { return m_userPassword; }
     QString userPasswordSecondary() const { return m_userPasswordSecondary; }
+    int userPasswordValidity() const;
+    QString userPasswordStatus() const;
+
     // The root password **may** be entered in the UI, or may be suppressed
     //   entirely when writeRootPassword is off, or may be equal to
     //   the user password when reuseUserPasswordForRoot is on.
     QString rootPassword() const;
     QString rootPasswordSecondary() const;
+    int rootPasswordValidity() const;
+    QString rootPasswordStatus() const;
 
     static const QStringList& forbiddenLoginNames();
     static const QStringList& forbiddenHostNames();
@@ -193,11 +224,15 @@ signals:
     void requireStrongPasswordsChanged( bool );
     void userPasswordChanged( const QString& );
     void userPasswordSecondaryChanged( const QString& );
+    void userPasswordStatusChanged( int, QString& );
     void rootPasswordChanged( const QString& );
     void rootPasswordSecondaryChanged( const QString& );
+    void rootPasswordStatusChanged( int, QString& );
 
 
 private:
+    QPair< PasswordValidity, QString > passwordStatus( const QString&, const QString& ) const;
+
     QStringList m_defaultGroups;
     QString m_userShell;
     QString m_autologinGroup;

src/modules/users/UsersPage.cpp

@@ -248,8 +248,11 @@ UsersPage::reportHostNameStatus( const QString& status )
 }
 
 bool
-UsersPage::checkPasswordAcceptance( const QString& pw1, const QString& pw2, QLabel* badge, QLabel* message )
+UsersPage::checkPasswordAcceptance( Password p, QLabel* badge, QLabel* message )
 {
+    QString pw1 = p == Password::User ? m_config->userPassword() : m_config->rootPassword();
+    QString pw2 = p == Password::User ? m_config->userPasswordSecondary() : m_config->rootPasswordSecondary();
+
     if ( pw1 != pw2 )
     {
         labelError( badge, message, tr( "Your passwords do not match!" ), Badness::Fatal );
@@ -278,9 +281,7 @@ UsersPage::checkPasswordAcceptance( const QString& pw1, const QString& pw2, QLab
 void
 UsersPage::onPasswordTextChanged( const QString& )
 {
-    m_readyPassword = checkPasswordAcceptance( ui->textBoxUserPassword->text(),
-                                               ui->textBoxUserVerifiedPassword->text(),
-                                               ui->labelUserPassword,
+    m_readyPassword = checkPasswordAcceptance( Password::User, ui->labelUserPassword,
                                                ui->labelUserPasswordError );
 
     emit checkReady( isReady() );
@@ -289,9 +290,7 @@ UsersPage::onPasswordTextChanged( const QString& )
 void
 UsersPage::onRootPasswordTextChanged( const QString& )
 {
-    m_readyRootPassword = checkPasswordAcceptance( ui->textBoxRootPassword->text(),
-                                                   ui->textBoxVerifiedRootPassword->text(),
-                                                   ui->labelRootPassword,
+    m_readyRootPassword = checkPasswordAcceptance( Password::Root, ui->labelRootPassword,
                                                    ui->labelRootPasswordError );
     emit checkReady( isReady() );
 }

src/modules/users/UsersPage.h

@@ -60,13 +60,15 @@ signals:
     void checkReady( bool );
 
 private:
+    /// @brief Which password are we talking about? (for checkPasswordAcceptance())
+    enum class Password { Root, User };
     /** @brief Is the password acceptable?
      *
      * Checks the two copies of the password and places error messages in the
      * given QLabels. Returns true (and clears the error messages) if the
      * password is acceptable.
      */
-    bool checkPasswordAcceptance( const QString& pw1, const QString& pw2, QLabel* badge, QLabel* message );
+    bool checkPasswordAcceptance( Password p, QLabel* badge, QLabel* message );
 
     void retranslate();