]> git.mxchange.org Git - flightgear.git/commitdiff
Stop using property listener for fgValidatePath
authorRebecca N. Palmer <rebecca_palmer@zoho.com>
Fri, 13 Mar 2015 17:54:44 +0000 (17:54 +0000)
committerRebecca N. Palmer <rebecca_palmer@zoho.com>
Fri, 13 Mar 2015 17:54:44 +0000 (17:54 +0000)
This was insecure: while removelistener() won't remove it, there are
other ways to remove a listener from Nasal

src/Main/util.cxx
src/Main/util.hxx
src/Scripting/NasalSys.cxx

index 5eed377345eeeb3cc6bb20d1d30b4a5c9732f3f7..28ee477359db9e884742ebe2220d0daaa5c4d2e7 100644 (file)
@@ -33,6 +33,7 @@
 #include <simgear/math/SGLimits.hxx>
 #include <simgear/math/SGMisc.hxx>
 
+#include <GUI/MessageBox.hxx>
 #include "fg_io.hxx"
 #include "fg_props.hxx"
 #include "globals.hxx"
@@ -71,32 +72,142 @@ fgGetLowPass (double current, double target, double timeratio)
     return current;
 }
 
-// Write out path to validation node and read it back in. A Nasal
-// listener is supposed to replace the path with a validated version
-// or an empty string otherwise.
-const char *fgValidatePath (const char *str, bool write)
+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()
 {
-    SGPropertyNode_ptr r, w;
-    r = fgGetNode("/sim/paths/validate/read", true);
-    r->setAttribute(SGPropertyNode::READ, true);
-    r->setAttribute(SGPropertyNode::WRITE, true);
-
-    w = fgGetNode("/sim/paths/validate/write", true);
-    w->setAttribute(SGPropertyNode::READ, true);
-    w->setAttribute(SGPropertyNode::WRITE, true);
-
-    SGPropertyNode *prop = write ? w : r;
-    prop->setStringValue(str);
-    const char *result = prop->getStringValue();
-    return result[0] ? result : 0;
+    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");
+    
+    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").c_str(),true) ||
+        !fgValidatePath(globals->get_fg_home() + "no.log",true).empty() ||
+        !fgValidatePath("..\\" + globals->get_fg_home() + "/no.log",false).empty() ||
+        fgValidatePath("/tmp/no.xml",false) ||
+        fgValidatePath(globals->get_fg_home() + "/./ff/../Export\\yes..gg",true).empty() ||
+        !fgValidatePath((globals->get_fg_home() + "/aircraft-data/yes..xml").c_str(),true) ||
+        fgValidatePath(globals->get_fg_root() + "/./\\yes.bmp",false).empty()) {
+            flightgear::fatalMessageBox("Nasal initialization error",
+                                    "fgInitAllowedPaths() does not work",
+                                    "");
+            exit(-1);
+    }
 }
 
-//------------------------------------------------------------------------------
-std::string fgValidatePath(const std::string& path, bool write)
+// 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)
 {
-  const char* validate_path = fgValidatePath(path.c_str(), write);
-  return std::string(validate_path ? validate_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 "";
+}
+// s.c_str() becomes invalid when s is destroyed, so need a static s
+std::string validate_path_temp;
+const char* fgValidatePath(const char* path, bool write)
+{
+  validate_path_temp = fgValidatePath(std::string(path), write);
+  if(validate_path_temp.empty()){
+      return 0;
+  }
+  return validate_path_temp.c_str();
+}
 // end of util.cxx
 
index 5172ca23e12be59494122c3444fe62fdda68617b..37f401d955274b4332d3c75583c103d4ed560542 100644 (file)
@@ -36,7 +36,7 @@
 double fgGetLowPass (double current, double target, double timeratio);
 
 /**
- * Validation listener interface for io.nas, used by fgcommands.
+ * File access control, used by Nasal and fgcommands.
  * @param path Path to be validated
  * @param write True for write operations and false for read operations.
  * @return The validated path on success or 0 if access denied.
@@ -44,4 +44,9 @@ double fgGetLowPass (double current, double target, double timeratio);
 const char *fgValidatePath (const char *path, bool write);
 std::string fgValidatePath(const std::string& path, bool write);
 
+/**
+ * Set allowed paths for fgValidatePath
+ */
+void fgInitAllowedPaths();
+
 #endif // __UTIL_HXX
index 0e9f656bee07bc33cee69b101c3d294e921f8551..421965e48f9107826935c1ffc4dc43f9f73a9153 100644 (file)
@@ -835,6 +835,9 @@ void FGNasalSys::init()
       .member("singleShot", &TimerObj::isSingleShot, &TimerObj::setSingleShot)
       .member("isRunning", &TimerObj::isRunning);
 
+    // Set allowed paths for Nasal I/O
+    fgInitAllowedPaths();
+    
     // Now load the various source files in the Nasal directory
     simgear::Dir nasalDir(SGPath(globals->get_fg_root(), "Nasal"));
     loadScriptDirectory(nasalDir);