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: ResolverThunk()22 ResolverThunk() {} ~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__ 106