+static string_list read_allowed_paths;
+static string_list write_allowed_paths;
+
+// Allowed paths here are absolute, and may contain _one_ *,
+// which matches any string
+// FG_SCENERY is deliberately not allowed, as it would make
+// /sim/terrasync/scenery-dir a security hole
+void fgInitAllowedPaths()
+{
+ read_allowed_paths.clear();
+ write_allowed_paths.clear();
+ read_allowed_paths.push_back(globals->get_fg_root() + "/*");
+ read_allowed_paths.push_back(globals->get_fg_home() + "/*");
+ string_list const aircraft_paths = globals->get_aircraft_paths();
+ for( string_list::const_iterator it = aircraft_paths.begin();
+ it != aircraft_paths.end();
+ ++it )
+ {
+ read_allowed_paths.push_back(*it + "/*");
+ }
+
+ for( string_list::const_iterator it = read_allowed_paths.begin();
+ it != read_allowed_paths.end();
+ ++it )
+ { // if we get the initialization order wrong, better to have an
+ // obvious error than a can-read-everything security hole...
+ if (!(it->compare("/*"))){
+ flightgear::fatalMessageBox("Nasal initialization error",
+ "Empty string in FG_ROOT, FG_HOME or FG_AIRCRAFT",
+ "or fgInitAllowedPaths() called too early");
+ exit(-1);
+ }
+ }
+ write_allowed_paths.push_back("/tmp/*.xml");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/*.sav");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/*.log");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/cache/*");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/Export/*");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/state/*.xml");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/aircraft-data/*.xml");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/Wildfire/*.xml");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/runtime-jetways/*.xml");
+ write_allowed_paths.push_back(globals->get_fg_home() + "/Input/Joysticks/*.xml");
+
+ // Check that it works
+ if(!fgValidatePath(globals->get_fg_home() + "/../no.log",true).empty() ||
+ !fgValidatePath(globals->get_fg_home() + "/no.lot",true).empty() ||
+ !fgValidatePath(globals->get_fg_home() + "/nolog",true).empty() ||
+ !fgValidatePath(globals->get_fg_home() + "no.log",true).empty() ||
+ !fgValidatePath("..\\" + globals->get_fg_home() + "/no.log",false).empty() ||
+ !fgValidatePath(std::string("/tmp/no.xml"),false).empty() ||
+ fgValidatePath(globals->get_fg_home() + "/./ff/../Export\\yes..gg",true).empty() ||
+ fgValidatePath(globals->get_fg_home() + "/aircraft-data/yes..xml",true).empty() ||
+ fgValidatePath(globals->get_fg_root() + "/./\\yes.bmp",false).empty()) {
+ flightgear::fatalMessageBox("Nasal initialization error",
+ "fgInitAllowedPaths() does not work",
+ "");
+ exit(-1);
+ }
+}
+
+// Normalize a path
+// Unlike SGPath::realpath, does not require that the file already exists,
+// but does require that it be below the starting point
+static std::string fgNormalizePath (const std::string& path)
+{
+ string_list path_parts;
+ char c;
+ std::string normed_path = "", this_part = "";
+
+ for (int pos = 0; ; pos++) {
+ c = path[pos];
+ if (c == '\\') { c = '/'; }
+ if ((c == '/') || (c == 0)) {
+ if ((this_part == "/..") || (this_part == "..")) {
+ if (path_parts.empty()) { return ""; }
+ path_parts.pop_back();
+ } else if ((this_part != "/.") && (this_part != "/")) {
+ path_parts.push_back(this_part);
+ }
+ this_part = "";
+ }
+ if (c == 0) { break; }
+ this_part = this_part + c;
+ }
+ for( string_list::const_iterator it = path_parts.begin();
+ it != path_parts.end();
+ ++it )
+ {
+ normed_path.append(*it);
+ }
+ return normed_path;
+ }
+
+
+// Check whether Nasal is allowed to access a path
+std::string fgValidatePath (const std::string& path, bool write)
+{
+ const string_list& allowed_paths(write ? write_allowed_paths : read_allowed_paths);
+ int star_pos;
+
+ // Normalize the path (prevents ../../.. trickery)
+ std::string normed_path = fgNormalizePath(path);
+
+ // Check against each allowed pattern
+ for( string_list::const_iterator it = allowed_paths.begin();
+ it != allowed_paths.end();
+ ++it )
+ {
+ star_pos = it->find('*');
+ if (star_pos == std::string::npos) {
+ if (!(it->compare(normed_path))) {
+ return normed_path;
+ }
+ } else {
+ if ((it->size()-1 <= normed_path.size()) /* long enough to be a potential match */
+ && !(it->substr(0,star_pos)
+ .compare(normed_path.substr(0,star_pos))) /* before-star parts match */
+ && !(it->substr(star_pos+1,it->size()-star_pos-1)
+ .compare(normed_path.substr(star_pos+1+normed_path.size()-it->size(),
+ it->size()-star_pos-1))) /* after-star parts match */) {
+ return normed_path;
+ }
+ }
+ }
+ // no match found
+ return "";
+}
+std::string fgValidatePath(const SGPath& path, bool write) { return fgValidatePath(path.str(),write); }