Add ExceptionBarrier to module scanning in the hope of reducing some false po...

chrome_frame/module_utils.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome_frame/module_utils.h"
 
 #include <atlbase.h>
 #include <TlHelp32.h>
 
 #include "base/scoped_ptr.h"
 #include "base/file_version_info.h"
 #include "base/logging.h"
 #include "base/scoped_handle.h"
 #include "base/string_util.h"
 #include "base/version.h"
+#include "chrome_frame/exception_barrier.h"
 
 DllRedirector::DllRedirector() : dcgo_ptr_(NULL), initialized_(false),
                                  module_handle_(NULL) {}
 
 DllRedirector::~DllRedirector() {
   if (module_handle_) {
     FreeLibrary(module_handle_);
     module_handle_ = NULL;
   }
 }
@@ skipping 39 matching lines @@
                                                REFCLSID clsid,
                                                HMODULE* oldest_module_handle) {
   DCHECK(oldest_module_handle);
 
   ScopedHandle snapshot(CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, 0));
   if (snapshot == INVALID_HANDLE_VALUE) {
     LOG(ERROR) << "Could not create module snapshot!";
     return false;
   }
 
+
   bool success = false;
   PathToHModuleMap map;
 
-  // First get the list of module paths, and save the full path to base address
-  // mapping.
-  MODULEENTRY32W module_entry;
-  module_entry.dwSize = sizeof(module_entry);
-  BOOL cont = Module32FirstW(snapshot, &module_entry);
-  while (cont) {
-    if (!lstrcmpi(module_entry.szModule, module_name.c_str())) {
-      std::wstring full_path(module_entry.szExePath);
-      map[full_path] = module_entry.hModule;
+  {
+    // Here we add an SEH to the chain to prevent our VEH from picking up on any
+    // exceptions thrown in DLLs who hook some of the below api calls. We will
+    // still report the exceptions if they make our way back to us, the hope is
+    // that they will not.
+    ExceptionBarrier exception_barrier;
+
+    // First get the list of module paths, and save the full path to base
+    // address mapping.
+    MODULEENTRY32W module_entry = {0};
+    module_entry.dwSize = sizeof(module_entry);
+    BOOL cont = Module32FirstW(snapshot, &module_entry);
+    while (cont) {
+      if (!lstrcmpi(module_entry.szModule, module_name.c_str())) {
+        std::wstring full_path(module_entry.szExePath);
+        map[full_path] = module_entry.hModule;
+      }
+      SecureZeroMemory(&module_entry, sizeof(MODULEENTRY32W));
+      module_entry.dwSize = sizeof(module_entry);
+      cont = Module32NextW(snapshot, &module_entry);
     }
-    cont = Module32NextW(snapshot, &module_entry);
   }
 
   // Next, enumerate the map and find the oldest version of the module.
   // (check if the map is of size 1 first)
   if (!map.empty()) {
     if (map.size() == 1) {
       *oldest_module_handle = map.begin()->second;
     } else {
       *oldest_module_handle = GetHandleOfOldestModule(map, clsid);
     }
@@ skipping 67 matching lines @@
       LOG(ERROR) << "Module Scan: Couldn't get address of "
                  << "DllGetClassObject: "
                  << GetLastError();
     }
   } else {
     LOG(ERROR) << "Module Scan: Could not increment module count: "
                << GetLastError();
   }
   return proc_ptr;
 }