michael@0: // Copyright (c) 2010 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: // Defines ResolverThunk, the interface for classes that perform interceptions.
michael@0: // For more details see
michael@0: // http://dev.chromium.org/developers/design-documents/sandbox .
michael@0: 
michael@0: #include "base/basictypes.h"
michael@0: #include "sandbox/win/src/nt_internals.h"
michael@0: 
michael@0: #ifndef SANDBOX_SRC_RESOLVER_H__
michael@0: #define SANDBOX_SRC_RESOLVER_H__
michael@0: 
michael@0: namespace sandbox {
michael@0: 
michael@0: // A resolver is the object in charge of performing the actual interception of
michael@0: // a function. There should be a concrete implementation of a resolver roughly
michael@0: // per type of interception.
michael@0: class ResolverThunk {
michael@0:  public:
michael@0:   ResolverThunk() {}
michael@0:   virtual ~ResolverThunk() {}
michael@0: 
michael@0:   // Performs the actual interception of a function.
michael@0:   // target_name is an exported function from the module loaded at
michael@0:   // target_module, and must be replaced by interceptor_name, exported from
michael@0:   // interceptor_module. interceptor_entry_point can be provided instead of
michael@0:   // interceptor_name / interceptor_module.
michael@0:   // thunk_storage must point to a buffer on the child's address space, to hold
michael@0:   // the patch thunk, and related data. If provided, storage_used will receive
michael@0:   // the number of bytes used from thunk_storage.
michael@0:   //
michael@0:   // Example: (without error checking)
michael@0:   //
michael@0:   // size_t size = resolver.GetThunkSize();
michael@0:   // char* buffer = ::VirtualAllocEx(child_process, NULL, size,
michael@0:   //                                 MEM_COMMIT, PAGE_READWRITE);
michael@0:   // resolver.Setup(ntdll_module, NULL, L"NtCreateFile", NULL,
michael@0:   //                &MyReplacementFunction, buffer, size, NULL);
michael@0:   //
michael@0:   // In general, the idea is to allocate a single big buffer for all
michael@0:   // interceptions on the same dll, and call Setup n times.
michael@0:   // WARNING: This means that any data member that is specific to a single
michael@0:   // interception must be reset within this method.
michael@0:   virtual NTSTATUS Setup(const void* target_module,
michael@0:                          const void* interceptor_module,
michael@0:                          const char* target_name,
michael@0:                          const char* interceptor_name,
michael@0:                          const void* interceptor_entry_point,
michael@0:                          void* thunk_storage,
michael@0:                          size_t storage_bytes,
michael@0:                          size_t* storage_used) = 0;
michael@0: 
michael@0:   // Gets the address of function_name inside module (main exe).
michael@0:   virtual NTSTATUS ResolveInterceptor(const void* module,
michael@0:                                       const char* function_name,
michael@0:                                       const void** address);
michael@0: 
michael@0:   // Gets the address of an exported function_name inside module.
michael@0:   virtual NTSTATUS ResolveTarget(const void* module,
michael@0:                                  const char* function_name,
michael@0:                                  void** address);
michael@0: 
michael@0:   // Gets the required buffer size for this type of thunk.
michael@0:   virtual size_t GetThunkSize() const = 0;
michael@0: 
michael@0:  protected:
michael@0:   // Performs basic initialization on behalf of a concrete instance of a
michael@0:   // resolver. That is, parameter validation and resolution of the target
michael@0:   // and the interceptor into the member variables.
michael@0:   //
michael@0:   // target_name is an exported function from the module loaded at
michael@0:   // target_module, and must be replaced by interceptor_name, exported from
michael@0:   // interceptor_module. interceptor_entry_point can be provided instead of
michael@0:   // interceptor_name / interceptor_module.
michael@0:   // thunk_storage must point to a buffer on the child's address space, to hold
michael@0:   // the patch thunk, and related data.
michael@0:   virtual NTSTATUS Init(const void* target_module,
michael@0:                         const void* interceptor_module,
michael@0:                         const char* target_name,
michael@0:                         const char* interceptor_name,
michael@0:                         const void* interceptor_entry_point,
michael@0:                         void* thunk_storage,
michael@0:                         size_t storage_bytes);
michael@0: 
michael@0:   // Gets the required buffer size for the internal part of the thunk.
michael@0:   size_t GetInternalThunkSize() const;
michael@0: 
michael@0:   // Initializes the internal part of the thunk.
michael@0:   // interceptor is the function to be called instead of original_function.
michael@0:   bool SetInternalThunk(void* storage, size_t storage_bytes,
michael@0:                         const void* original_function, const void* interceptor);
michael@0: 
michael@0:   // Holds the resolved interception target.
michael@0:   void* target_;
michael@0:   // Holds the resolved interception interceptor.
michael@0:   const void* interceptor_;
michael@0: 
michael@0:   DISALLOW_COPY_AND_ASSIGN(ResolverThunk);
michael@0: };
michael@0: 
michael@0: }  // namespace sandbox
michael@0: 
michael@0: #endif  // SANDBOX_SRC_RESOLVER_H__