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| 1 // Copyright (c) 2006-2008 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 #include "sandbox/src/sidestep_resolver.h" | |
| 6 | |
| 7 #include "base/win/pe_image.h" | |
| 8 #include "sandbox/src/sandbox_nt_util.h" | |
| 9 #include "sandbox/src/sidestep/preamble_patcher.h" | |
| 10 | |
| 11 namespace { | |
| 12 | |
| 13 const size_t kSizeOfSidestepStub = sidestep::kMaxPreambleStubSize; | |
| 14 | |
| 15 struct SidestepThunk { | |
| 16 char sidestep[kSizeOfSidestepStub]; // Storage for the sidestep stub. | |
| 17 int internal_thunk; // Dummy member to the beginning of the internal thunk. | |
| 18 }; | |
| 19 | |
| 20 struct SmartThunk { | |
| 21 const void* module_base; // Target module's base. | |
| 22 const void* interceptor; // Real interceptor. | |
| 23 SidestepThunk sidestep; // Standard sidestep thunk. | |
| 24 }; | |
| 25 | |
| 26 } // namespace | |
| 27 | |
| 28 namespace sandbox { | |
| 29 | |
| 30 NTSTATUS SidestepResolverThunk::Setup(const void* target_module, | |
| 31 const void* interceptor_module, | |
| 32 const char* target_name, | |
| 33 const char* interceptor_name, | |
| 34 const void* interceptor_entry_point, | |
| 35 void* thunk_storage, | |
| 36 size_t storage_bytes, | |
| 37 size_t* storage_used) { | |
| 38 NTSTATUS ret = Init(target_module, interceptor_module, target_name, | |
| 39 interceptor_name, interceptor_entry_point, | |
| 40 thunk_storage, storage_bytes); | |
| 41 if (!NT_SUCCESS(ret)) | |
| 42 return ret; | |
| 43 | |
| 44 SidestepThunk* thunk = reinterpret_cast<SidestepThunk*>(thunk_storage); | |
| 45 | |
| 46 size_t internal_bytes = storage_bytes - kSizeOfSidestepStub; | |
| 47 if (!SetInternalThunk(&thunk->internal_thunk, internal_bytes, thunk_storage, | |
| 48 interceptor_)) | |
| 49 return STATUS_BUFFER_TOO_SMALL; | |
| 50 | |
| 51 AutoProtectMemory memory; | |
| 52 memory.ChangeProtection(target_, kSizeOfSidestepStub, PAGE_READWRITE); | |
| 53 | |
| 54 sidestep::SideStepError rv = sidestep::PreamblePatcher::Patch( | |
| 55 target_, reinterpret_cast<void*>(&thunk->internal_thunk), thunk_storage, | |
| 56 kSizeOfSidestepStub); | |
| 57 | |
| 58 if (sidestep::SIDESTEP_INSUFFICIENT_BUFFER == rv) | |
| 59 return STATUS_BUFFER_TOO_SMALL; | |
| 60 | |
| 61 if (sidestep::SIDESTEP_SUCCESS != rv) | |
| 62 return STATUS_UNSUCCESSFUL; | |
| 63 | |
| 64 if (storage_used) | |
| 65 *storage_used = GetThunkSize(); | |
| 66 | |
| 67 return ret; | |
| 68 } | |
| 69 | |
| 70 size_t SidestepResolverThunk::GetThunkSize() const { | |
| 71 return GetInternalThunkSize() + kSizeOfSidestepStub; | |
| 72 } | |
| 73 | |
| 74 // This is basically a wrapper around the normal sidestep patch that extends | |
| 75 // the thunk to use a chained interceptor. It uses the fact that | |
| 76 // SetInternalThunk generates the code to pass as the first parameter whatever | |
| 77 // it receives as original_function; we let SidestepResolverThunk set this value | |
| 78 // to its saved code, and then we change it to our thunk data. | |
| 79 NTSTATUS SmartSidestepResolverThunk::Setup(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 size_t* storage_used) { | |
| 87 if (storage_bytes < GetThunkSize()) | |
| 88 return STATUS_BUFFER_TOO_SMALL; | |
| 89 | |
| 90 SmartThunk* thunk = reinterpret_cast<SmartThunk*>(thunk_storage); | |
| 91 thunk->module_base = target_module; | |
| 92 | |
| 93 NTSTATUS ret; | |
| 94 if (interceptor_entry_point) { | |
| 95 thunk->interceptor = interceptor_entry_point; | |
| 96 } else { | |
| 97 ret = ResolveInterceptor(interceptor_module, interceptor_name, | |
| 98 &thunk->interceptor); | |
| 99 if (!NT_SUCCESS(ret)) | |
| 100 return ret; | |
| 101 } | |
| 102 | |
| 103 // Perform a standard sidestep patch on the last part of the thunk, but point | |
| 104 // to our internal smart interceptor. | |
| 105 size_t standard_bytes = storage_bytes - offsetof(SmartThunk, sidestep); | |
| 106 ret = SidestepResolverThunk::Setup(target_module, interceptor_module, | |
| 107 target_name, NULL, &SmartStub, | |
| 108 &thunk->sidestep, standard_bytes, NULL); | |
| 109 if (!NT_SUCCESS(ret)) | |
| 110 return ret; | |
| 111 | |
| 112 // Fix the internal thunk to pass the whole buffer to the interceptor. | |
| 113 SetInternalThunk(&thunk->sidestep.internal_thunk, GetInternalThunkSize(), | |
| 114 thunk_storage, &SmartStub); | |
| 115 | |
| 116 if (storage_used) | |
| 117 *storage_used = GetThunkSize(); | |
| 118 | |
| 119 return ret; | |
| 120 } | |
| 121 | |
| 122 size_t SmartSidestepResolverThunk::GetThunkSize() const { | |
| 123 return GetInternalThunkSize() + kSizeOfSidestepStub + | |
| 124 offsetof(SmartThunk, sidestep); | |
| 125 } | |
| 126 | |
| 127 // This code must basically either call the intended interceptor or skip the | |
| 128 // call and invoke instead the original function. In any case, we are saving | |
| 129 // the registers that may be trashed by our c++ code. | |
| 130 // | |
| 131 // This function is called with a first parameter inserted by us, that points | |
| 132 // to our SmartThunk. When we call the interceptor we have to replace this | |
| 133 // parameter with the one expected by that function (stored inside our | |
| 134 // structure); on the other hand, when we skip the interceptor we have to remove | |
| 135 // that extra argument before calling the original function. | |
| 136 // | |
| 137 // When we skip the interceptor, the transformation of the stack looks like: | |
| 138 // On Entry: On Use: On Exit: | |
| 139 // [param 2] = first real argument [param 2] (esp+1c) [param 2] | |
| 140 // [param 1] = our SmartThunk [param 1] (esp+18) [ret address] | |
| 141 // [ret address] = real caller [ret address] (esp+14) [xxx] | |
| 142 // [xxx] [addr to jump to] (esp+10) [xxx] | |
| 143 // [xxx] [saved eax] [xxx] | |
| 144 // [xxx] [saved ebx] [xxx] | |
| 145 // [xxx] [saved ecx] [xxx] | |
| 146 // [xxx] [saved edx] [xxx] | |
| 147 __declspec(naked) | |
| 148 void SmartSidestepResolverThunk::SmartStub() { | |
| 149 __asm { | |
| 150 push eax // Space for the jump. | |
| 151 push eax // Save registers. | |
| 152 push ebx | |
| 153 push ecx | |
| 154 push edx | |
| 155 mov ebx, [esp + 0x18] // First parameter = SmartThunk. | |
| 156 mov edx, [esp + 0x14] // Get the return address. | |
| 157 mov eax, [ebx]SmartThunk.module_base | |
| 158 push edx | |
| 159 push eax | |
| 160 call SmartSidestepResolverThunk::IsInternalCall | |
| 161 add esp, 8 | |
| 162 | |
| 163 test eax, eax | |
| 164 lea edx, [ebx]SmartThunk.sidestep // The original function. | |
| 165 jz call_interceptor | |
| 166 | |
| 167 // Skip this call | |
| 168 mov ecx, [esp + 0x14] // Return address. | |
| 169 mov [esp + 0x18], ecx // Remove first parameter. | |
| 170 mov [esp + 0x10], edx | |
| 171 pop edx // Restore registers. | |
| 172 pop ecx | |
| 173 pop ebx | |
| 174 pop eax | |
| 175 ret 4 // Jump to original function. | |
| 176 | |
| 177 call_interceptor: | |
| 178 mov ecx, [ebx]SmartThunk.interceptor | |
| 179 mov [esp + 0x18], edx // Replace first parameter. | |
| 180 mov [esp + 0x10], ecx | |
| 181 pop edx // Restore registers. | |
| 182 pop ecx | |
| 183 pop ebx | |
| 184 pop eax | |
| 185 ret // Jump to original function. | |
| 186 } | |
| 187 } | |
| 188 | |
| 189 bool SmartSidestepResolverThunk::IsInternalCall(const void* base, | |
| 190 void* return_address) { | |
| 191 DCHECK_NT(base); | |
| 192 DCHECK_NT(return_address); | |
| 193 | |
| 194 base::win::PEImage pe(base); | |
| 195 if (pe.GetImageSectionFromAddr(return_address)) | |
| 196 return true; | |
| 197 return false; | |
| 198 } | |
| 199 | |
| 200 } // namespace sandbox | |
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Chromium Code Reviews
Issue 10783004:
Move Windows Sandbox, trybots version (don't commit me!) (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src