Don't read unlimited data from files

It now guards against reading infinite files such as `/dev/zero`.
And most readings are bound with a (lax) limit.
As a side effect, more checking are done when reading a file and
overall the reading procedure is more robust.

PR #19095.

src/gui/aboutdialog.cpp

@@ -28,11 +28,10 @@
 
 #include "aboutdialog.h"
 
-#include <QFile>
-
 #include "base/global.h"
 #include "base/path.h"
 #include "base/unicodestrings.h"
+#include "base/utils/io.h"
 #include "base/utils/misc.h"
 #include "base/version.h"
 #include "ui_aboutdialog.h"
@@ -75,27 +74,24 @@ AboutDialog::AboutDialog(QWidget *parent)
     m_ui->labelMascot->setPixmap(Utils::Gui::scaledPixmap(Path(u":/icons/mascot.png"_qs), this));
 
     // Thanks
-    QFile thanksfile(u":/thanks.html"_qs);
-    if (thanksfile.open(QIODevice::ReadOnly | QIODevice::Text))
+    if (const auto readResult = Utils::IO::readFile(Path(u":/thanks.html"_qs), -1, QIODevice::Text)
+        ; readResult)
     {
-        m_ui->textBrowserThanks->setHtml(QString::fromUtf8(thanksfile.readAll().constData()));
-        thanksfile.close();
+        m_ui->textBrowserThanks->setHtml(QString::fromUtf8(readResult.value()));
     }
 
     // Translation
-    QFile translatorsfile(u":/translators.html"_qs);
-    if (translatorsfile.open(QIODevice::ReadOnly | QIODevice::Text))
+    if (const auto readResult = Utils::IO::readFile(Path(u":/translators.html"_qs), -1, QIODevice::Text)
+        ; readResult)
     {
-        m_ui->textBrowserTranslation->setHtml(QString::fromUtf8(translatorsfile.readAll().constData()));
-        translatorsfile.close();
+        m_ui->textBrowserTranslation->setHtml(QString::fromUtf8(readResult.value()));
     }
 
     // License
-    QFile licensefile(u":/gpl.html"_qs);
-    if (licensefile.open(QIODevice::ReadOnly | QIODevice::Text))
+    if (const auto readResult = Utils::IO::readFile(Path(u":/gpl.html"_qs), -1, QIODevice::Text)
+        ; readResult)
     {
-        m_ui->textBrowserLicense->setHtml(QString::fromUtf8(licensefile.readAll().constData()));
-        licensefile.close();
+        m_ui->textBrowserLicense->setHtml(QString::fromUtf8(readResult.value()));
     }
 
     // Software Used

src/gui/optionsdialog.cpp

@@ -52,6 +52,7 @@
 #include "base/rss/rss_session.h"
 #include "base/torrentfileguard.h"
 #include "base/torrentfileswatcher.h"
+#include "base/utils/io.h"
 #include "base/utils/misc.h"
 #include "base/utils/net.h"
 #include "base/utils/password.h"
@@ -1751,46 +1752,22 @@ Path OptionsDialog::getFilter() const
 #ifndef DISABLE_WEBUI
 void OptionsDialog::webUIHttpsCertChanged(const Path &path)
 {
-    const auto isCertFileValid = [&path]() -> bool
-    {
-        if (path.isEmpty())
-            return false;
-
-        QFile file {path.data()};
-        if (!file.open(QIODevice::ReadOnly))
-            return false;
-
-        if (!Utils::Net::isSSLCertificatesValid(file.read(Utils::Net::MAX_SSL_FILE_SIZE)))
-            return false;
-
-        return true;
-    };
+    const auto readResult = Utils::IO::readFile(path, Utils::Net::MAX_SSL_FILE_SIZE);
+    const bool isCertValid = Utils::Net::isSSLCertificatesValid(readResult.value_or(QByteArray()));
 
     m_ui->textWebUIHttpsCert->setSelectedPath(path);
     m_ui->lblSslCertStatus->setPixmap(UIThemeManager::instance()->getScaledPixmap(
-        (isCertFileValid() ? u"security-high"_qs : u"security-low"_qs), 24));
+        (isCertValid ? u"security-high"_qs : u"security-low"_qs), 24));
 }
 
 void OptionsDialog::webUIHttpsKeyChanged(const Path &path)
 {
-    const auto isKeyFileValid = [&path]() -> bool
-    {
-        if (path.isEmpty())
-            return false;
-
-        QFile file {path.data()};
-        if (!file.open(QIODevice::ReadOnly))
-            return false;
-
-        if (!Utils::Net::isSSLKeyValid(file.read(Utils::Net::MAX_SSL_FILE_SIZE)))
-            return false;
-
-        return true;
-    };
+    const auto readResult = Utils::IO::readFile(path, Utils::Net::MAX_SSL_FILE_SIZE);
+    const bool isKeyValid = Utils::Net::isSSLKeyValid(readResult.value_or(QByteArray()));
 
     m_ui->textWebUIHttpsKey->setSelectedPath(path);
     m_ui->lblSslKeyStatus->setPixmap(UIThemeManager::instance()->getScaledPixmap(
-        (isKeyFileValid() ? u"security-high"_qs : u"security-low"_qs), 24));
+        (isKeyValid ? u"security-high"_qs : u"security-low"_qs), 24));
 }
 
 bool OptionsDialog::isWebUiEnabled() const

src/gui/previewselectdialog.cpp

@@ -30,7 +30,6 @@
 
 #include <QAction>
 #include <QDir>
-#include <QFile>
 #include <QHeaderView>
 #include <QMenu>
 #include <QMessageBox>

src/gui/rss/automatedrssdownloader.cpp

@@ -458,15 +458,16 @@ void AutomatedRssDownloader::onImportBtnClicked()
     const Path path {QFileDialog::getOpenFileName(
                     this, tr("Import RSS rules"), QDir::homePath()
                     , u"%1;;%2"_qs.arg(m_formatFilterJSON, m_formatFilterLegacy), &selectedFilter)};
-    if (!path.exists())
-        return;
 
-    QFile file {path.data()};
-    if (!file.open(QIODevice::ReadOnly))
+    const int fileMaxSize = 10 * 1024 * 1024;
+    const auto readResult = Utils::IO::readFile(path, fileMaxSize);
+    if (!readResult)
     {
-        QMessageBox::critical(
-                    this, tr("I/O Error")
-                    , tr("Failed to open the file. Reason: %1").arg(file.errorString()));
+        if (readResult.error().status == Utils::IO::ReadError::NotExist)
+            return;
+
+        QMessageBox::critical(this, tr("Import error")
+            , tr("Failed to read the file. %1").arg(readResult.error().message));
         return;
     }
 
@@ -479,13 +480,12 @@ void AutomatedRssDownloader::onImportBtnClicked()
 
     try
     {
-        RSS::AutoDownloader::instance()->importRules(file.readAll(),format);
+        RSS::AutoDownloader::instance()->importRules(readResult.value(), format);
     }
     catch (const RSS::ParsingError &error)
     {
-        QMessageBox::critical(
-                    this, tr("Import Error")
-                    , tr("Failed to import the selected rules file. Reason: %1").arg(error.message()));
+        QMessageBox::critical(this, tr("Import error")
+            , tr("Failed to import the selected rules file. Reason: %1").arg(error.message()));
     }
 }
 

src/gui/uithemedialog.cpp

@@ -30,7 +30,6 @@
 
 #include <QColor>
 #include <QColorDialog>
-#include <QFile>
 #include <QFileDialog>
 #include <QJsonDocument>
 #include <QJsonObject>

src/gui/uithemesource.cpp

@@ -30,30 +30,17 @@
 
 #include "uithemesource.h"
 
-#include <QFile>
 #include <QJsonDocument>
 #include <QJsonObject>
 
 #include "base/global.h"
 #include "base/logger.h"
 #include "base/profile.h"
+#include "base/utils/io.h"
 
 namespace
 {
-    QByteArray readFile(const Path &filePath)
-    {
-        QFile file {filePath.data()};
-        if (!file.exists())
-            return {};
-
-        if (file.open(QIODevice::ReadOnly | QIODevice::Text))
-            return file.readAll();
-
-        LogMsg(UIThemeSource::tr("UITheme - Failed to open \"%1\". Reason: %2")
-               .arg(filePath.filename(), file.errorString())
-               , Log::WARNING);
-        return {};
-    }
+    const qint64 FILE_MAX_SIZE = 1024 * 1024;
 
     QJsonObject parseThemeConfig(const QByteArray &data)
     {
@@ -165,7 +152,16 @@ Path DefaultThemeSource::getIconPath(const QString &iconId, const ColorMode colo
 
 void DefaultThemeSource::loadColors()
 {
-    const QByteArray configData = readFile(m_userPath / Path(CONFIG_FILE_NAME));
+    const auto readResult = Utils::IO::readFile((m_userPath / Path(CONFIG_FILE_NAME)), FILE_MAX_SIZE, QIODevice::Text);
+    if (!readResult)
+    {
+        if (readResult.error().status != Utils::IO::ReadError::NotExist)
+            LogMsg(tr("Failed to load default theme colors. %1").arg(readResult.error().message), Log::WARNING);
+
+        return;
+    }
+
+    const QByteArray configData = readResult.value();
     if (configData.isEmpty())
         return;
 
@@ -233,7 +229,16 @@ Path CustomThemeSource::getIconPath(const QString &iconId, const ColorMode color
 
 QByteArray CustomThemeSource::readStyleSheet()
 {
-    return readFile(themeRootPath() / Path(STYLESHEET_FILE_NAME));
+    const auto readResult = Utils::IO::readFile((themeRootPath() / Path(STYLESHEET_FILE_NAME)), FILE_MAX_SIZE, QIODevice::Text);
+    if (!readResult)
+    {
+        if (readResult.error().status != Utils::IO::ReadError::NotExist)
+            LogMsg(tr("Failed to load custom theme style sheet. %1").arg(readResult.error().message), Log::WARNING);
+
+        return {};
+    }
+
+    return readResult.value();
 }
 
 DefaultThemeSource *CustomThemeSource::defaultThemeSource() const
@@ -243,7 +248,16 @@ DefaultThemeSource *CustomThemeSource::defaultThemeSource() const
 
 void CustomThemeSource::loadColors()
 {
-    const QByteArray configData = readFile(themeRootPath() / Path(CONFIG_FILE_NAME));
+    const auto readResult = Utils::IO::readFile((themeRootPath() / Path(CONFIG_FILE_NAME)), FILE_MAX_SIZE, QIODevice::Text);
+    if (!readResult)
+    {
+        if (readResult.error().status != Utils::IO::ReadError::NotExist)
+            LogMsg(tr("Failed to load custom theme colors. %1").arg(readResult.error().message), Log::WARNING);
+
+        return;
+    }
+
+    const QByteArray configData = readResult.value();
     if (configData.isEmpty())
         return;
 

src/gui/utils.cpp

@@ -177,10 +177,12 @@ void Utils::Gui::openFolderSelect(const Path &path)
     QObject::connect(thread, &QThread::finished, thread, &QObject::deleteLater);
     thread->start();
 #elif defined(Q_OS_UNIX) && !defined(Q_OS_MACOS)
+    const int lineMaxLength = 64;
+
     QProcess proc;
     proc.start(u"xdg-mime"_qs, {u"query"_qs, u"default"_qs, u"inode/directory"_qs});
     proc.waitForFinished();
-    const auto output = QString::fromLocal8Bit(proc.readLine().simplified());
+    const auto output = QString::fromLocal8Bit(proc.readLine(lineMaxLength).simplified());
     if ((output == u"dolphin.desktop") || (output == u"org.kde.dolphin.desktop"))
     {
         proc.startDetached(u"dolphin"_qs, {u"--select"_qs, path.toString()});
@@ -190,7 +192,7 @@ void Utils::Gui::openFolderSelect(const Path &path)
     {
         proc.start(u"nautilus"_qs, {u"--version"_qs});
         proc.waitForFinished();
-        const auto nautilusVerStr = QString::fromLocal8Bit(proc.readLine()).remove(QRegularExpression(u"[^0-9.]"_qs));
+        const auto nautilusVerStr = QString::fromLocal8Bit(proc.readLine(lineMaxLength)).remove(QRegularExpression(u"[^0-9.]"_qs));
         using NautilusVersion = Utils::Version<3>;
         if (NautilusVersion::fromString(nautilusVerStr, {1, 0, 0}) > NautilusVersion(3, 28, 0))
             proc.startDetached(u"nautilus"_qs, {(Fs::isDir(path) ? path.parentPath() : path).toString()});