Bug 642469 - Sanitize the environment variables upon startup; r=bsmedberg

xpcom/base/nsSetDllDirectory.cpp

@@ -41,8 +41,31 @@
 #endif
 
 #include <windows.h>
+#include <stdlib.h>
 #include "nsSetDllDirectory.h"
 
+void
+SanitizeEnvironmentVariables()
+{
+  DWORD bufferSize = GetEnvironmentVariableW(L"PATH", NULL, 0);
+  if (bufferSize) {
+    wchar_t* originalPath = new wchar_t[bufferSize];
+    if (bufferSize - 1 == GetEnvironmentVariableW(L"PATH", originalPath, bufferSize)) {
+      bufferSize = ExpandEnvironmentStringsW(originalPath, NULL, 0);
+      if (bufferSize) {
+        wchar_t* newPath = new wchar_t[bufferSize];
+        if (ExpandEnvironmentStringsW(originalPath,
+                                      newPath,
+                                      bufferSize)) {
+          SetEnvironmentVariableW(L"PATH", newPath);
+        }
+        delete[] newPath;
+      }
+    }
+    delete[] originalPath;
+  }
+}
+
 namespace mozilla {
 
 XPCOM_API(void)
@@ -54,6 +77,10 @@ NS_SetDllDirectory(const WCHAR *aDllDirectory)
   if (!setDllDirectory) {
     setDllDirectory = reinterpret_cast<pfnSetDllDirectory>
       (GetProcAddress(GetModuleHandleW(L"kernel32.dll"), "SetDllDirectoryW"));
+
+    // If it's the first time we're running this function, sanitize the
+    // environment variables too.
+    SanitizeEnvironmentVariables();
   }
   if (setDllDirectory) {
     setDllDirectory(aDllDirectory);