sandbox/win/src/resolver.h

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Defines ResolverThunk, the interface for classes that perform interceptions.
   6 // For more details see
   7 // http://dev.chromium.org/developers/design-documents/sandbox .
   8
   9 #include "base/basictypes.h"
  10 #include "sandbox/win/src/nt_internals.h"
  11
  12 #ifndef SANDBOX_SRC_RESOLVER_H__
  13 #define SANDBOX_SRC_RESOLVER_H__
  14
  15 namespace sandbox {
  16
  17 // A resolver is the object in charge of performing the actual interception of
  18 // a function. There should be a concrete implementation of a resolver roughly
  19 // per type of interception.
  20 class ResolverThunk {
  21  public:
  22   ResolverThunk() {}
  23   virtual ~ResolverThunk() {}
  24
  25   // Performs the actual interception of a function.
  26   // target_name is an exported function from the module loaded at
  27   // target_module, and must be replaced by interceptor_name, exported from
  28   // interceptor_module. interceptor_entry_point can be provided instead of
  29   // interceptor_name / interceptor_module.
  30   // thunk_storage must point to a buffer on the child's address space, to hold
  31   // the patch thunk, and related data. If provided, storage_used will receive
  32   // the number of bytes used from thunk_storage.
  33   //
  34   // Example: (without error checking)
  35   //
  36   // size_t size = resolver.GetThunkSize();
  37   // char* buffer = ::VirtualAllocEx(child_process, NULL, size,
  38   //                                 MEM_COMMIT, PAGE_READWRITE);
  39   // resolver.Setup(ntdll_module, NULL, L"NtCreateFile", NULL,
  40   //                &MyReplacementFunction, buffer, size, NULL);
  41   //
  42   // In general, the idea is to allocate a single big buffer for all
  43   // interceptions on the same dll, and call Setup n times.
  44   // WARNING: This means that any data member that is specific to a single
  45   // interception must be reset within this method.
  46   virtual NTSTATUS Setup(const void* target_module,
  47                          const void* interceptor_module,
  48                          const char* target_name,
  49                          const char* interceptor_name,
  50                          const void* interceptor_entry_point,
  51                          void* thunk_storage,
  52                          size_t storage_bytes,
  53                          size_t* storage_used) = 0;
  54
  55   // Gets the address of function_name inside module (main exe).
  56   virtual NTSTATUS ResolveInterceptor(const void* module,
  57                                       const char* function_name,
  58                                       const void** address);
  59
  60   // Gets the address of an exported function_name inside module.
  61   virtual NTSTATUS ResolveTarget(const void* module,
  62                                  const char* function_name,
  63                                  void** address);
  64
  65   // Gets the required buffer size for this type of thunk.
  66   virtual size_t GetThunkSize() const = 0;
  67
  68  protected:
  69   // Performs basic initialization on behalf of a concrete instance of a
  70   // resolver. That is, parameter validation and resolution of the target
  71   // and the interceptor into the member variables.
  72   //
  73   // target_name is an exported function from the module loaded at
  74   // target_module, and must be replaced by interceptor_name, exported from
  75   // interceptor_module. interceptor_entry_point can be provided instead of
  76   // interceptor_name / interceptor_module.
  77   // thunk_storage must point to a buffer on the child's address space, to hold
  78   // the patch thunk, and related data.
  79   virtual NTSTATUS Init(const void* target_module,
  80                         const void* interceptor_module,
  81                         const char* target_name,
  82                         const char* interceptor_name,
  83                         const void* interceptor_entry_point,
  84                         void* thunk_storage,
  85                         size_t storage_bytes);
  86
  87   // Gets the required buffer size for the internal part of the thunk.
  88   size_t GetInternalThunkSize() const;
  89
  90   // Initializes the internal part of the thunk.
  91   // interceptor is the function to be called instead of original_function.
  92   bool SetInternalThunk(void* storage, size_t storage_bytes,
  93                         const void* original_function, const void* interceptor);
  94
  95   // Holds the resolved interception target.
  96   void* target_;
  97   // Holds the resolved interception interceptor.
  98   const void* interceptor_;
  99
 100   DISALLOW_COPY_AND_ASSIGN(ResolverThunk);
 101 };
 102
 103 }  // namespace sandbox
 104
 105 #endif  // SANDBOX_SRC_RESOLVER_H__