From 462b681679d6c78b695c5394c21b5140b4fb7bd2 Mon Sep 17 00:00:00 2001
From: Matthias Melcher <git@matthiasm.com>
Date: Fri, 3 Jan 2020 17:42:22 +0100
Subject: [PATCH] Linux/MSWindows: improved Fl_Preferences file path checking

---
 .../WinAPI/Fl_WinAPI_System_Driver.cxx        | 26 +++++++++----
 src/drivers/X11/Fl_X11_System_Driver.cxx      | 37 ++++++++++++++-----
 2 files changed, 46 insertions(+), 17 deletions(-)

diff --git a/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx b/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx
index dc7960e62..f28802ba0 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx
+++ b/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx
@@ -827,10 +827,13 @@ char *Fl_WinAPI_System_Driver::preference_rootnode(Fl_Preferences *prefs, Fl_Pre
 {
 #  define FLPREFS_RESOURCE	"Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders"
 #  define FLPREFS_RESOURCEW	L"Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders"
-  static char filename[ FL_PATH_MAX ];
+  static char *filename = 0L;
+  // make enough room for a UTF16 pathname
+  if (!filename) filename = (char*)::malloc(2*FL_PATH_MAX);
   filename[0] = 0;
+  filename[1] = 0;
   size_t appDataLen = strlen(vendor) + strlen(application) + 8;
-  DWORD type, nn;
+  DWORD nn;
   LONG err;
   HKEY key;
   
@@ -839,9 +842,9 @@ char *Fl_WinAPI_System_Driver::preference_rootnode(Fl_Preferences *prefs, Fl_Pre
       err = RegOpenKeyW( HKEY_LOCAL_MACHINE, FLPREFS_RESOURCEW, &key );
       if (err == ERROR_SUCCESS) {
         nn = (DWORD) (FL_PATH_MAX - appDataLen);
-        err = RegQueryValueExW( key, L"Common AppData", 0L, &type,
+        err = RegQueryValueExW( key, L"Common AppData", 0L, 0L,
                                (BYTE*)filename, &nn );
-        if ( ( err != ERROR_SUCCESS ) && ( type == REG_SZ ) ) {
+        if ( err != ERROR_SUCCESS ) {
           filename[0] = 0;
           filename[1] = 0;
         }
@@ -852,9 +855,9 @@ char *Fl_WinAPI_System_Driver::preference_rootnode(Fl_Preferences *prefs, Fl_Pre
       err = RegOpenKeyW( HKEY_CURRENT_USER, FLPREFS_RESOURCEW, &key );
       if (err == ERROR_SUCCESS) {
         nn = (DWORD) (FL_PATH_MAX - appDataLen);
-        err = RegQueryValueExW( key, L"AppData", 0L, &type,
+        err = RegQueryValueExW( key, L"AppData", 0L,0L,
                                (BYTE*)filename, &nn );
-        if ( ( err != ERROR_SUCCESS ) && ( type == REG_SZ ) ) {
+        if ( err != ERROR_SUCCESS ) {
           filename[0] = 0;
           filename[1] = 0;
         }
@@ -863,7 +866,9 @@ char *Fl_WinAPI_System_Driver::preference_rootnode(Fl_Preferences *prefs, Fl_Pre
       break;
   }
   if (!filename[1] && !filename[0]) {
-    strcpy(filename, "C:\\FLTK");
+    // Don't write data into some arbitrary directory! Just return NULL.
+    //strcpy(filename, "C:\\FLTK");
+    return 0L;
   } else {
 #if 0
     wchar_t *b = (wchar_t*)_wcsdup((wchar_t *)filename);
@@ -879,6 +884,13 @@ char *Fl_WinAPI_System_Driver::preference_rootnode(Fl_Preferences *prefs, Fl_Pre
     filename[len] = 0;
     free(b);
   }
+
+  // Make sure that the parameters are not NULL
+  if ( (vendor==0L) || (vendor[0]==0) )
+    vendor = "unknown";
+  if ( (application==0L) || (application[0]==0) )
+    application = "unknown";
+
   snprintf(filename + strlen(filename), sizeof(filename) - strlen(filename),
            "/%s/%s.prefs", vendor, application);
   for (char *s = filename; *s; s++) if (*s == '\\') *s = '/';
diff --git a/src/drivers/X11/Fl_X11_System_Driver.cxx b/src/drivers/X11/Fl_X11_System_Driver.cxx
index b84aba8ea..11e56de23 100644
--- a/src/drivers/X11/Fl_X11_System_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_System_Driver.cxx
@@ -24,6 +24,10 @@
 #include <X11/Xlib.h>
 #include <locale.h>
 #include <time.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <pwd.h>
+
 
 #if defined(_AIX)
 extern "C" {
@@ -397,24 +401,37 @@ void Fl_X11_System_Driver::newUUID(char *uuidBuffer)
 char *Fl_X11_System_Driver::preference_rootnode(Fl_Preferences *prefs, Fl_Preferences::Root root, const char *vendor,
                                                 const char *application)
 {
-  static char filename[ FL_PATH_MAX ]; filename[0] = 0;
+  static char *filename = 0L;
+  if (!filename) filename = (char*)::calloc(1, FL_PATH_MAX);
   const char *e;
   switch (root&Fl_Preferences::ROOT_MASK) {
     case Fl_Preferences::USER:
-      if ((e = getenv("HOME")) != NULL) {
-        strlcpy(filename, e, sizeof(filename));
-        
-        if (filename[strlen(filename)-1] != '/') {
-          strlcat(filename, "/.fltk/", sizeof(filename));
-        } else {
-          strlcat(filename, ".fltk/", sizeof(filename));
-        }
-        break;
+      e = getenv("HOME");
+      // make sure that $HOME is set to an existing directory
+      if ( (e==0L) || (e[0]=0) || (::access(e, F_OK)==-1) ) ) {
+        struct passwd *pw = getpwuid(getuid());
+        e = pw->pw_dir;
       }
+      if ( (e==0L) || (e[0]=0) || (::access(e, F_OK)==-1) ) ) {
+        return 0L;
+      } else {
+        strlcpy(filename, e, sizeof(filename));
+        if (filename[strlen(filename)-1] != '/')
+          strlcat(filename, "/", sizeof(filename));
+        strlcat(filename, ".fltk/", sizeof(filename));
+      }
+      break;
     case Fl_Preferences::SYSTEM:
       strcpy(filename, "/etc/fltk/");
       break;
   }
+    
+  // Make sure that the parameters are not NULL
+  if ( (vendor==0L) || (vendor[0]==0) )
+    vendor = "unknown";
+  if ( (application==0L) || (application[0]==0) )
+    application = "unknown";
+
   snprintf(filename + strlen(filename), sizeof(filename) - strlen(filename),
            "%s/%s.prefs", vendor, application);
   return filename;