Calling SendSAS() from a service yo make sure that Secure Attention Sequence can be injected even w…

remoting/host/sas_injector_win.cc

 // Copyright (c) 2012 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 "remoting/host/sas_injector.h"
 
 #include <windows.h>
 #include <string>
 
 #include "base/logging.h"
@@ skipping 16 matching lines @@
 
 // The prototype of SendSAS().
 typedef VOID (WINAPI *SendSasFunc)(BOOL);
 
 // The registry key and value holding the policy controlling software SAS
 // generation.
 const wchar_t kSystemPolicyKeyName[] =
     L"Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System";
 const wchar_t kSoftwareSasValueName[] = L"SoftwareSASGeneration";
 
-const DWORD kEnableSoftwareSasByApps = 2;
+const DWORD kEnableSoftwareSasByServices = 1;
 
 // Toggles the default software SAS generation policy to enable SAS generation
-// by applications. Non-default policy is not changed.
+// by services. Non-default policy is not changed.
 class ScopedSoftwareSasPolicy {
  public:
   ScopedSoftwareSasPolicy();
   ~ScopedSoftwareSasPolicy();
 
   bool Apply();
 
  private:
   // The handle of the registry key were SoftwareSASGeneration policy is stored.
   base::win::RegKey system_policy_;
@@ skipping 31 matching lines @@
     LOG_GETLASTERROR(ERROR) << "Failed to open 'HKLM\\"
                             << kSystemPolicyKeyName << "'";
     return false;
   }
 
   bool custom_policy = system_policy_.HasValue(kSoftwareSasValueName);
 
   // Override the default policy (i.e. there is no value in the registry) only.
   if (!custom_policy) {
     result = system_policy_.WriteValue(kSoftwareSasValueName,
-                                       kEnableSoftwareSasByApps);
+                                       kEnableSoftwareSasByServices);
     if (result != ERROR_SUCCESS) {
       SetLastError(result);
       LOG_GETLASTERROR(ERROR)
           << "Failed to enable software SAS generation by services";
       return false;
     } else {
       restore_policy_ = true;
     }
   }
 
   return true;
 }
 
 } // namespace
 
-// Sends the Secure Attention Sequence using the SendSAS() function from
-// sas.dll. This library is shipped starting from Win7/W2K8 R2 only. However
-// Win7 SDK includes a redistributable verion of the same library that works on
+// Sends Secure Attention Sequence using the SendSAS() function from sas.dll.
+// This library is shipped starting from Win7/W2K8 R2 only. However Win7 SDK
+// includes a redistributable verion of the same library that works on
 // Vista/W2K8. We install the latter along with our binaries.
 class SasInjectorWin : public SasInjector {
  public:
   SasInjectorWin();
   virtual ~SasInjectorWin();
 
   // SasInjector implementation.
   virtual bool InjectSas() OVERRIDE;
 
  private:
@@ skipping 42 matching lines @@
     send_sas_ = static_cast<SendSasFunc>(
         sas_dll_.GetFunctionPointer(kSendSasName));
   }
   if (send_sas_ == NULL) {
     LOG(ERROR) << "Failed to retrieve the address of '" << kSendSasName
                << "()'";
     return false;
   }
 
   // Enable software SAS generation by services and send SAS. SAS can still fail
-  // if the policy does not allow applications to generate software SAS.
+  // if the policy does not allow services to generate software SAS.
   ScopedSoftwareSasPolicy enable_sas;
   if (!enable_sas.Apply())
     return false;
 
   (*send_sas_)(FALSE);
   return true;
 }
 
 SasInjectorXp::SasInjectorXp() {
 }
@@ skipping 28 matching lines @@
 
 scoped_ptr<SasInjector> SasInjector::Create() {
   if (base::win::GetVersion() < base::win::VERSION_VISTA) {
     return scoped_ptr<SasInjector>(new SasInjectorXp());
   } else {
     return scoped_ptr<SasInjector>(new SasInjectorWin());
   }
 }
 
 } // namespace remoting