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| 1 // Copyright (c) 2006-2010 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 // For information about interceptions as a whole see | |
| 6 // http://dev.chromium.org/developers/design-documents/sandbox . | |
| 7 | |
| 8 #include "sandbox/win/src/interception_agent.h" | |
| 9 | |
| 10 #include <stddef.h> | |
| 11 | |
| 12 #include "sandbox/win/src/eat_resolver.h" | |
| 13 #include "sandbox/win/src/interception_internal.h" | |
| 14 #include "sandbox/win/src/interceptors.h" | |
| 15 #include "sandbox/win/src/sandbox_nt_util.h" | |
| 16 #include "sandbox/win/src/sidestep_resolver.h" | |
| 17 | |
| 18 namespace { | |
| 19 | |
| 20 // Returns true if target lies between base and base + range. | |
| 21 bool IsWithinRange(const void* base, size_t range, const void* target) { | |
| 22 const char* end = reinterpret_cast<const char*>(base) + range; | |
| 23 return reinterpret_cast<const char*>(target) < end; | |
| 24 } | |
| 25 | |
| 26 } // namespace | |
| 27 | |
| 28 namespace sandbox { | |
| 29 | |
| 30 // This is the list of all imported symbols from ntdll.dll. | |
| 31 SANDBOX_INTERCEPT NtExports g_nt; | |
| 32 | |
| 33 // The list of intercepted functions back-pointers. | |
| 34 SANDBOX_INTERCEPT OriginalFunctions g_originals; | |
| 35 | |
| 36 // Memory buffer mapped from the parent, with the list of interceptions. | |
| 37 SANDBOX_INTERCEPT SharedMemory* g_interceptions = NULL; | |
| 38 | |
| 39 InterceptionAgent* InterceptionAgent::GetInterceptionAgent() { | |
| 40 static InterceptionAgent* s_singleton = NULL; | |
| 41 if (!s_singleton) { | |
| 42 if (!g_interceptions) | |
| 43 return NULL; | |
| 44 | |
| 45 size_t array_bytes = g_interceptions->num_intercepted_dlls * sizeof(void*); | |
| 46 s_singleton = reinterpret_cast<InterceptionAgent*>( | |
| 47 new(NT_ALLOC) char[array_bytes + sizeof(InterceptionAgent)]); | |
| 48 | |
| 49 bool success = s_singleton->Init(g_interceptions); | |
| 50 if (!success) { | |
| 51 operator delete(s_singleton, NT_ALLOC); | |
| 52 s_singleton = NULL; | |
| 53 } | |
| 54 } | |
| 55 return s_singleton; | |
| 56 } | |
| 57 | |
| 58 bool InterceptionAgent::Init(SharedMemory* shared_memory) { | |
| 59 interceptions_ = shared_memory; | |
| 60 for (int i = 0 ; i < shared_memory->num_intercepted_dlls; i++) | |
| 61 dlls_[i] = NULL; | |
| 62 return true; | |
| 63 } | |
| 64 | |
| 65 bool InterceptionAgent::DllMatch(const UNICODE_STRING* full_path, | |
| 66 const UNICODE_STRING* name, | |
| 67 const DllPatchInfo* dll_info) { | |
| 68 UNICODE_STRING current_name; | |
| 69 current_name.Length = static_cast<USHORT>(g_nt.wcslen(dll_info->dll_name) * | |
| 70 sizeof(wchar_t)); | |
| 71 current_name.MaximumLength = current_name.Length; | |
| 72 current_name.Buffer = const_cast<wchar_t*>(dll_info->dll_name); | |
| 73 | |
| 74 BOOLEAN case_insensitive = TRUE; | |
| 75 if (full_path && | |
| 76 !g_nt.RtlCompareUnicodeString(¤t_name, full_path, case_insensitive)) | |
| 77 return true; | |
| 78 | |
| 79 if (name && | |
| 80 !g_nt.RtlCompareUnicodeString(¤t_name, name, case_insensitive)) | |
| 81 return true; | |
| 82 | |
| 83 return false; | |
| 84 } | |
| 85 | |
| 86 bool InterceptionAgent::OnDllLoad(const UNICODE_STRING* full_path, | |
| 87 const UNICODE_STRING* name, | |
| 88 void* base_address) { | |
| 89 DllPatchInfo* dll_info = interceptions_->dll_list; | |
| 90 int i = 0; | |
| 91 for (; i < interceptions_->num_intercepted_dlls; i++) { | |
| 92 if (DllMatch(full_path, name, dll_info)) | |
| 93 break; | |
| 94 | |
| 95 dll_info = reinterpret_cast<DllPatchInfo*>( | |
| 96 reinterpret_cast<char*>(dll_info) + dll_info->record_bytes); | |
| 97 } | |
| 98 | |
| 99 // Return now if the dll is not in our list of interest. | |
| 100 if (i == interceptions_->num_intercepted_dlls) | |
| 101 return true; | |
| 102 | |
| 103 // The dll must be unloaded. | |
| 104 if (dll_info->unload_module) | |
| 105 return false; | |
| 106 | |
| 107 // Purify causes this condition to trigger. | |
| 108 if (dlls_[i]) | |
| 109 return true; | |
| 110 | |
| 111 size_t buffer_bytes = offsetof(DllInterceptionData, thunks) + | |
| 112 dll_info->num_functions * sizeof(ThunkData); | |
| 113 dlls_[i] = reinterpret_cast<DllInterceptionData*>( | |
| 114 new(NT_PAGE, base_address) char[buffer_bytes]); | |
| 115 | |
| 116 DCHECK_NT(dlls_[i]); | |
| 117 if (!dlls_[i]) | |
| 118 return true; | |
| 119 | |
| 120 dlls_[i]->data_bytes = buffer_bytes; | |
| 121 dlls_[i]->num_thunks = 0; | |
| 122 dlls_[i]->base = base_address; | |
| 123 dlls_[i]->used_bytes = offsetof(DllInterceptionData, thunks); | |
| 124 | |
| 125 VERIFY(PatchDll(dll_info, dlls_[i])); | |
| 126 | |
| 127 ULONG old_protect; | |
| 128 SIZE_T real_size = buffer_bytes; | |
| 129 void* to_protect = dlls_[i]; | |
| 130 VERIFY_SUCCESS(g_nt.ProtectVirtualMemory(NtCurrentProcess, &to_protect, | |
| 131 &real_size, PAGE_EXECUTE_READ, | |
| 132 &old_protect)); | |
| 133 return true; | |
| 134 } | |
| 135 | |
| 136 void InterceptionAgent::OnDllUnload(void* base_address) { | |
| 137 for (int i = 0; i < interceptions_->num_intercepted_dlls; i++) { | |
| 138 if (dlls_[i] && dlls_[i]->base == base_address) { | |
| 139 operator delete(dlls_[i], NT_PAGE); | |
| 140 dlls_[i] = NULL; | |
| 141 break; | |
| 142 } | |
| 143 } | |
| 144 } | |
| 145 | |
| 146 // TODO(rvargas): We have to deal with prebinded dlls. I see two options: change | |
| 147 // the timestamp of the patched dll, or modify the info on the prebinded dll. | |
| 148 // the first approach messes matching of debug symbols, the second one is more | |
| 149 // complicated. | |
| 150 bool InterceptionAgent::PatchDll(const DllPatchInfo* dll_info, | |
| 151 DllInterceptionData* thunks) { | |
| 152 DCHECK_NT(NULL != thunks); | |
| 153 DCHECK_NT(NULL != dll_info); | |
| 154 | |
| 155 const FunctionInfo* function = reinterpret_cast<const FunctionInfo*>( | |
| 156 reinterpret_cast<const char*>(dll_info) + dll_info->offset_to_functions); | |
| 157 | |
| 158 for (int i = 0; i < dll_info->num_functions; i++) { | |
| 159 if (!IsWithinRange(dll_info, dll_info->record_bytes, function->function)) { | |
| 160 NOTREACHED_NT(); | |
| 161 return false; | |
| 162 } | |
| 163 | |
| 164 ResolverThunk* resolver = GetResolver(function->type); | |
| 165 if (!resolver) | |
| 166 return false; | |
| 167 | |
| 168 const char* interceptor = function->function + | |
| 169 g_nt.strlen(function->function) + 1; | |
| 170 | |
| 171 if (!IsWithinRange(function, function->record_bytes, interceptor) || | |
| 172 !IsWithinRange(dll_info, dll_info->record_bytes, interceptor)) { | |
| 173 NOTREACHED_NT(); | |
| 174 return false; | |
| 175 } | |
| 176 | |
| 177 NTSTATUS ret = resolver->Setup(thunks->base, | |
| 178 interceptions_->interceptor_base, | |
| 179 function->function, | |
| 180 interceptor, | |
| 181 function->interceptor_address, | |
| 182 &thunks->thunks[i], | |
| 183 sizeof(ThunkData), | |
| 184 NULL); | |
| 185 if (!NT_SUCCESS(ret)) { | |
| 186 NOTREACHED_NT(); | |
| 187 return false; | |
| 188 } | |
| 189 | |
| 190 DCHECK_NT(!g_originals[function->id]); | |
| 191 g_originals[function->id] = &thunks->thunks[i]; | |
| 192 | |
| 193 thunks->num_thunks++; | |
| 194 thunks->used_bytes += sizeof(ThunkData); | |
| 195 | |
| 196 function = reinterpret_cast<const FunctionInfo*>( | |
| 197 reinterpret_cast<const char*>(function) + function->record_bytes); | |
| 198 } | |
| 199 | |
| 200 return true; | |
| 201 } | |
| 202 | |
| 203 // This method is called from within the loader lock | |
| 204 ResolverThunk* InterceptionAgent::GetResolver(InterceptionType type) { | |
| 205 static EatResolverThunk* eat_resolver = NULL; | |
| 206 static SidestepResolverThunk* sidestep_resolver = NULL; | |
| 207 static SmartSidestepResolverThunk* smart_sidestep_resolver = NULL; | |
| 208 | |
| 209 if (!eat_resolver) | |
| 210 eat_resolver = new(NT_ALLOC) EatResolverThunk; | |
| 211 | |
| 212 #if !defined(_WIN64) | |
| 213 // Sidestep is not supported for x64. | |
| 214 if (!sidestep_resolver) | |
| 215 sidestep_resolver = new(NT_ALLOC) SidestepResolverThunk; | |
| 216 | |
| 217 if (!smart_sidestep_resolver) | |
| 218 smart_sidestep_resolver = new(NT_ALLOC) SmartSidestepResolverThunk; | |
| 219 #endif | |
| 220 | |
| 221 switch (type) { | |
| 222 case INTERCEPTION_EAT: | |
| 223 return eat_resolver; | |
| 224 case INTERCEPTION_SIDESTEP: | |
| 225 return sidestep_resolver; | |
| 226 case INTERCEPTION_SMART_SIDESTEP: | |
| 227 return smart_sidestep_resolver; | |
| 228 default: | |
| 229 NOTREACHED_NT(); | |
| 230 } | |
| 231 | |
| 232 return NULL; | |
| 233 } | |
| 234 | |
| 235 } // namespace sandbox | |
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