Merge branch 'jb44457_symlink_policy' into 'master'

Make it possible to limit to which extent buteo-mtp exposes symlinks

See merge request mer-core/buteo-mtp!24

init/systemd/buteo-mtp.service

@@ -2,7 +2,9 @@
 Description=MTP service
 
 [Service]
-ExecStart=/usr/lib/mtp/start-mtp.sh
+EnvironmentFile=-/etc/sysconfig/buteo-mtp
+EnvironmentFile=-/var/lib/environment/buteo-mtp/*.conf
+ExecStart=/usr/lib/mtp/mtp_service $SERVICE_PARAMETERS
 Restart=always
 RestartSec=1
 Nice=-10

mts/platform/storage/fsstorageplugin/fsstorageplugin.cpp

@@ -379,7 +379,7 @@ static void file_set_mtime(const QString &path, time_t t)
 FSStoragePlugin::FSStoragePlugin( quint32 storageId, MTPStorageType storageType, QString storagePath,
                                   QString volumeLabel, QString storageDescription ) :
   StoragePlugin(storageId),
-  m_storagePath(QDir(storagePath).absolutePath()),
+  m_storagePath(QDir(storagePath).canonicalPath()),
   m_root(0),
   m_writeObjectHandle(0),
   m_largestPuoid(0),
@@ -1144,6 +1144,45 @@ StorageItem* FSStoragePlugin::findStorageItemByPath( const QString &path )
     return storageItem;
 }
 
+FSStoragePlugin::SymLinkPolicy FSStoragePlugin::s_symLinkPolicy = SymLinkPolicy::Undefined;
+
+FSStoragePlugin::SymLinkPolicy FSStoragePlugin::symLinkPolicy()
+{
+    if (s_symLinkPolicy == SymLinkPolicy::Undefined) {
+        FSStoragePlugin::SymLinkPolicy usePolicy = SymLinkPolicy::Default;
+        QByteArray envData = qgetenv("BUTEO_MTP_SYMLINK_POLICY");
+        QString envValue = QString::fromUtf8(envData.data()).toLower();
+        if (envValue == "allowall" || envValue == "allow")
+            usePolicy = SymLinkPolicy::AllowAll;
+        else if (envValue == "allowwithinstorage" || envValue == "storage")
+            usePolicy = SymLinkPolicy::AllowWithinStorage;
+        else if (envValue == "denyall"  || envValue == "deny")
+            usePolicy = SymLinkPolicy::DenyAll;
+        else if (!envValue.isEmpty())
+            MTP_LOG_WARNING("unknown SymLinkPolicy:" << envValue);
+        setSymLinkPolicy(usePolicy);
+    }
+    return s_symLinkPolicy;
+}
+
+void FSStoragePlugin::setSymLinkPolicy(FSStoragePlugin::SymLinkPolicy policy)
+{
+    static const char * const lut[] = {
+        "Undefined",
+        "AllowAll",
+        "AllowWithinStorage",
+        "DenyAll",
+    };
+
+    if (s_symLinkPolicy != policy) {
+        MTP_LOG_INFO("SymLinkPolicy changed:"
+                     << lut[s_symLinkPolicy]
+                     << "->"
+                     << lut[policy]);
+        s_symLinkPolicy = policy;
+    }
+}
+
 /************************************************************
  * MTPrespCode FSStoragePlugin::addToStorage
  ***********************************************************/
@@ -1156,6 +1195,36 @@ MTPResponseCode FSStoragePlugin::addToStorage( const QString &path,
         return MTP_RESP_AccessDenied;
     }
 
+    // Handle symbolic link policy
+    QFileInfo pathInfo(path);
+    if (pathInfo.isSymLink()) {
+        QString targetPath(pathInfo.canonicalFilePath());
+        if (targetPath.isEmpty()) {
+            MTP_LOG_WARNING("excluded broken symlink:" << path);
+            return MTP_RESP_AccessDenied;
+        }
+        switch (symLinkPolicy()) {
+        case SymLinkPolicy::AllowAll:
+            break;
+        case SymLinkPolicy::AllowWithinStorage:
+            {
+                // NB: m_storagePath is in canonical form
+                int prefixLen = m_storagePath.length();
+                if (targetPath.length() <= prefixLen ||
+                    targetPath[prefixLen] != '/' ||
+                    !targetPath.startsWith(m_storagePath)) {
+                    MTP_LOG_INFO("excluded out-of-storage symlink:" << path);
+                    return MTP_RESP_AccessDenied;
+                }
+            }
+            break;
+        default:
+        case SymLinkPolicy::DenyAll:
+            MTP_LOG_INFO("excluded symlink:" << path);
+            return MTP_RESP_AccessDenied;
+        }
+    }
+
     // If we already have StorageItem for given path...
     if( m_pathNamesMap.contains( path ) )
     {

mts/platform/storage/fsstorageplugin/fsstorageplugin.h

@@ -57,6 +57,16 @@ class FSStoragePlugin : public StoragePlugin
 {
     Q_OBJECT
 public:
+    enum SymLinkPolicy {
+        Undefined,
+        AllowAll,
+        AllowWithinStorage,
+        DenyAll,
+        Default = AllowAll,
+    };
+    static SymLinkPolicy symLinkPolicy();
+    static void setSymLinkPolicy(SymLinkPolicy policy);
+
     /// Constructor.
     FSStoragePlugin( quint32 storageId = 0, MTPStorageType storageType = MTP_STORAGE_TYPE_FixedRAM,
                      QString storagePath = "", QString volumeLabel = "", QString storageDescription = "" );
@@ -433,6 +443,8 @@ private slots:
     ObjHandle m_testHandleProvider;
     friend class FSStoragePlugin_test;
 #endif
+
+    static SymLinkPolicy s_symLinkPolicy;
 };
 }
 

rpm/buteo-mtp-qt5.spec

@@ -17,6 +17,7 @@ BuildRequires: pkgconfig(buteosyncfw5)
 BuildRequires: pkgconfig(Qt5SystemInfo)
 BuildRequires: pkgconfig(blkid)
 BuildRequires: pkgconfig(mount)
+BuildRequires: pkgconfig(mlite5)
 # for the thumbnailer unit test
 BuildRequires: pkgconfig(Qt5Gui)
 BuildRequires: ssu-devel >= 0.37.9

service/service.cpp

@@ -25,12 +25,14 @@
 #include <signal.h>
 #include <iostream>
 #include <QCoreApplication>
+#include <QCommandLineParser>
 #include <QDir>
 #include <QObject>
 #include <QEventLoop>
 #include <QStringList>
 #include <QTimer>
 #include <Logger.h>
+#include <MGConfItem>
 #include "mts.h"
 
 using namespace meegomtp1dot0;
@@ -46,26 +48,53 @@ void signalHandler(int signum, siginfo_t *info, void *context)
     _exit(0);
 }
 
+static void setupSymLinkPolicy()
+{
+    MGConfItem confItem("/desktop/sailfish/buteo-mtp/symlink_policy");
+    QString symLinkPolicy(confItem.value().toString());
+
+    /* Note that we override value that might be existing in env,
+     * i.e. environment is used only as a vehicle for conveying the
+     * dconf setting data from main binary over to plugin that gets
+     * loaded at later stage.
+     */
+    qputenv("BUTEO_MTP_SYMLINK_POLICY", symLinkPolicy.toUtf8());
+}
+
 int main(int argc, char** argv)
 {
     QCoreApplication app(argc, argv);
+    QCommandLineParser parser;
+    parser.setApplicationDescription("standalone buteo-mtp daemon");
+    parser.addHelpOption();
+    QCommandLineOption logToHomeOption(QStringList() << "d" << "log-to-home",
+                                       "Log to \"$HOME/mtp.log\".");
+    parser.addOption(logToHomeOption);
+    parser.process(app);
+    bool logToHome(parser.isSet(logToHomeOption));
+
+    /* Get symlink policy from dconf */
+    setupSymLinkPolicy();
 
     struct sigaction action;
 
     action.sa_sigaction = signalHandler;
     action.sa_flags     = SA_SIGINFO | SA_RESTART;
     sigemptyset(&action.sa_mask);
 
-    if (sigaction(SIGINT, &action, NULL) < 0) return(-1);
-    if (sigaction(SIGALRM, &action, NULL) < 0) return(-1);
-    if (sigaction(SIGUSR1, &action, NULL) < 0) return(-1);
+    if (sigaction(SIGINT, &action, NULL) < 0)
+        return EXIT_FAILURE;
+    if (sigaction(SIGALRM, &action, NULL) < 0)
+        return EXIT_FAILURE;
+    if (sigaction(SIGUSR1, &action, NULL) < 0)
+        return EXIT_FAILURE;
 
     QObject::connect(&app,SIGNAL(aboutToQuit()),Mts::getInstance(),SLOT(destroyInstance()));
 
     bool ok = Mts::getInstance()->activate();
     if( ok )
     {
-        if (app.arguments().count() > 1 && app.arguments().at(1) == "-d")
+        if (logToHome)
         {
             Buteo::Logger::createInstance(QDir::homePath() + "/mtp.log", false, 0);
             if (!Mts::getInstance()->debugLogsEnabled())
@@ -81,5 +110,5 @@ int main(int argc, char** argv)
     {
         Mts::destroyInstance();
     }
-    return 0;
+    return EXIT_SUCCESS;
 }

service/service.pro

@@ -12,12 +12,13 @@ QT -= gui
 CONFIG += link_pkgconfig
 equals(QT_MAJOR_VERSION, 4): PKGCONFIG += buteosyncfw
 equals(QT_MAJOR_VERSION, 5): PKGCONFIG += buteosyncfw5
+PKGCONFIG += mlite5
 
 SOURCES += service.cpp
 
 #install
 target.path += /usr/lib/mtp/
-target.files = start-mtp.sh mtp_service
+target.files = mtp_service
 desktop.path = /etc/xdg/autostart
 desktop.files = buteo-mtp.desktop
 INSTALLS += target desktop