[mapplauncherd] Check sailjaild for sandboxing of apps. JB#54498 OMP#JOLLA-178

Check before executing if the arguments don't contain sailjaild and the
if the app should be launched in a sandbox. In that case prepend the
arguments with sailjail.

This is not sufficient alone as the apps are launched via silica-qt5
booster which can't execute sailjail so this must be also taken into
account already before arguments reach booster.

Signed-off-by: Tomi Leppänen <tomi.leppanen@jolla.com>

src/common/sailjail.c

@@ -26,6 +26,7 @@
 #define SAILJAIL_KEY_ORGANIZATION_NAME "OrganizationName"
 #define SAILJAIL_KEY_APPLICATION_NAME "ApplicationName"
 #define SAILJAIL_KEY_PERMISSIONS "Permissions"
+#define SAILJAIL_KEY_MODE "Mode"
 #define NEMO_KEY_APPLICATION_TYPE "X-Nemo-Application-Type"
 #define NEMO_KEY_SINGLE_INSTANCE "X-Nemo-Single-Instance"
 #define MAEMO_KEY_FIXED_ARGS "X-Maemo-Fixed-Args"
@@ -49,6 +50,10 @@
 #define PERMISSIONMGR_SIGNAL_APP_CHANGED "ApplicationChanged"
 #define PERMISSIONMGR_SIGNAL_APP_REMOVED "ApplicationRemoved"
 
+/* Sailjaild errors */
+#define CODE_INVALID_ARGS     "org.freedesktop.DBus.Error.InvalidArgs"
+#define ERROR_INVALID_APPNAME "Invalid application name: "
+
 static DBusConnection *
 sailjail_connect_bus(void)
 {
@@ -121,7 +126,7 @@ iter_at(DBusMessageIter *iter, int type)
 static GHashTable *
 sailjail_application_info(DBusConnection *con, const char *desktop)
 {
-    GHashTable *info = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, (GDestroyNotify)g_variant_unref);
+    GHashTable *info = NULL;
     DBusError err = DBUS_ERROR_INIT;
     DBusMessage *req = NULL;
     DBusMessage *rsp = NULL;
@@ -140,7 +145,10 @@ sailjail_application_info(DBusConnection *con, const char *desktop)
     }
 
     if (!(rsp = dbus_connection_send_with_reply_and_block(con, req, DBUS_TIMEOUT_INFINITE, &err))) {
+        if (strcmp(err.name, CODE_INVALID_ARGS) ||
+                strncmp(err.message, ERROR_INVALID_APPNAME, strlen(ERROR_INVALID_APPNAME))) {
             error("method call failed: %s: %s", err.name, err.message);
+        }
         goto EXIT;
     }
 
@@ -160,6 +168,8 @@ sailjail_application_info(DBusConnection *con, const char *desktop)
         goto EXIT;
     }
 
+    info = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, (GDestroyNotify)g_variant_unref);
+
     DBusMessageIter ArrayIter;
     dbus_message_iter_recurse(&bodyIter, &ArrayIter);
     while (!iter_at(&ArrayIter, DBUS_TYPE_INVALID)) {
@@ -557,3 +567,29 @@ EXIT:
 
     return allowed;
 }
+
+bool sailjail_sandbox(const char *desktop)
+{
+    bool sandboxed = false;
+    DBusConnection *con = NULL;
+    GHashTable *info = NULL;
+    const char *mode;
+
+    if (!(con = sailjail_connect_bus()))
+        goto EXIT;
+
+    if (!(info = sailjail_application_info(con, desktop)))
+        goto EXIT;
+
+    if ((mode = appinfo_string(info, SAILJAIL_KEY_MODE)) && g_strcmp0(mode, "None")) {
+        // Mode is either "Normal" or "Compatibility"
+        sandboxed = true;
+    }
+
+EXIT:
+    if (info)
+        g_hash_table_destroy(info);
+    sailjail_disconnect_bus(con);
+
+    return sandboxed;
+}

src/common/sailjail.h

@@ -6,8 +6,12 @@
 
 G_BEGIN_DECLS
 
+#define SAILJAIL_PATH "/usr/bin/sailjail"
+
 bool sailjail_verify_launch(const char *desktop, const char **argv);
 
+bool sailjail_sandbox(const char *desktop);
+
 G_END_DECLS
 
 #endif // SAILJAIL_H_

src/launcherlib/appdata.cpp

@@ -19,6 +19,7 @@
 
 #include "appdata.h"
 #include "protocol.h"
+#include "sailjail.h"
 #include <stdint.h>
 #include <stdio.h>
 #include <sys/types.h>
@@ -100,6 +101,16 @@ void AppData::setArgv(const char ** newArgv)
     }
 }
 
+void AppData::prependArgv(const char * arg)
+{
+    char **oldArgv = m_argv;
+    m_argv = (char **)calloc(++m_argc + 1, sizeof *m_argv);
+    m_argv[0] = strdup(arg);
+    for (int i = 1; i < m_argc + 1; ++i)
+        m_argv[i] = oldArgv[i-1];
+    free(oldArgv);
+}
+
 const char ** AppData::argv() const
 {
     return (const char **)m_argv;
@@ -237,6 +248,16 @@ void AppData::checkPrivileges()
         And then, any file in
             /usr/share/mapplauncherd/privileges.d/
      */
+
+    /* Sailjail does not use this system to gain privileged group.
+     * It is skipped to avoid unintended consequenses when launching
+     * other apps via sailjail.
+     */
+    if (m_fileName == SAILJAIL_PATH) {
+        m_privileges.clear();
+        return;
+    }
+
     static const char *BOOSTER_APP_PRIVILEGES_LIST = "/usr/share/mapplauncherd/privileges";
     static const char *BOOSTER_APP_PRIVILEGES_DIR = "/usr/share/mapplauncherd/privileges.d";
     m_privileges = getPrivileges(BOOSTER_APP_PRIVILEGES_LIST);

src/launcherlib/appdata.h

@@ -72,6 +72,9 @@ public:
     //! Set address of the argument vector
     void setArgv(const char ** argv);
 
+    //! Prepend to argv
+    void prependArgv(const char *arg);
+
     //! Return address of the argument vector
     const char ** argv() const;
 

src/launcherlib/booster.cpp

@@ -57,6 +57,11 @@
 
 #include "sailjail.h"
 
+static std::string basename(const std::string &str)
+{
+    return str.substr(str.find_last_of("/") + 1);
+}
+
 Booster::Booster() :
     m_appData(new AppData),
     m_connection(NULL),
@@ -287,6 +292,12 @@ int Booster::run(SocketManager * socketManager)
             if (boostedApplication() != "default") {
                 if (!sailjail_verify_launch(boostedApplication().c_str(), m_appData->argv()))
                     throw std::runtime_error("Booster: Binary doesn't have launch permissions\n");
+            } else if (m_appData->fileName() != SAILJAIL_PATH &&
+                    sailjail_sandbox(basename(m_appData->fileName()).c_str())) {
+                Logger::logDebug("Sandboxing '%s'", m_appData->fileName());
+                // Prepend sailjail to arguments
+                m_appData->prependArgv(SAILJAIL_PATH);
+                m_appData->setFileName(SAILJAIL_PATH);
             }
 
             return launchProcess();
@@ -701,7 +712,7 @@ void Booster::resetOomAdj()
 
 std::string Booster::getFinalName(const std::string &name)
 {
-    if (name == "/usr/bin/sailjail") {
+    if (name == SAILJAIL_PATH) {
         // This doesn't implement sailjail's parsing logic but instead
         // has some assumptions about the arguments:
         // - If there is --, then the application is