win: Make reading NT_IMAGE_HEADERS work cross-bitness

snapshot/win/pe_image_reader.cc

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 52 matching lines @@
 
   INITIALIZATION_STATE_SET_VALID(initialized_);
   return true;
 }
 
 bool PEImageReader::GetCrashpadInfo(
     process_types::CrashpadInfo* crashpad_info) const {
   INITIALIZATION_STATE_DCHECK_VALID(initialized_);
 
   IMAGE_SECTION_HEADER section;
-  if (!GetSectionByName("CPADinfo", &section))
-    return false;
+  if (process_reader_->Is64Bit()) {
+    if (!GetSectionByName<IMAGE_NT_HEADERS64>("CPADinfo", &section))
+      return false;
+  } else {
+    if (!GetSectionByName<IMAGE_NT_HEADERS32>("CPADinfo", &section))
+      return false;
+  }
 
   if (section.Misc.VirtualSize < sizeof(process_types::CrashpadInfo)) {
     LOG(WARNING) << "small crashpad info section size "
                  << section.Misc.VirtualSize << ", " << module_name_;
     return false;
   }
 
   WinVMAddress crashpad_info_address = Address() + section.VirtualAddress;
   CheckedWinAddressRange crashpad_info_range(process_reader_->Is64Bit(),
                                              crashpad_info_address,
@@ skipping 22 matching lines @@
       crashpad_info->version < 1) {
     LOG(WARNING) << "unexpected crashpad info data " << module_name_;
     return false;
   }
 
   return true;
 }
 
 bool PEImageReader::DebugDirectoryInformation(UUID* uuid,
                                               DWORD* age,
-                                              std::string* pdbname) {
+                                              std::string* pdbname) const {
+  if (process_reader_->Is64Bit()) {
+    return ReadDebugDirectoryInformation<IMAGE_NT_HEADERS64>(
+        uuid, age, pdbname);
+  } else {
+    return ReadDebugDirectoryInformation<IMAGE_NT_HEADERS32>(
+        uuid, age, pdbname);
+  }
+}
+
+template <class NtHeadersType>
+bool PEImageReader::ReadDebugDirectoryInformation(UUID* uuid,
+                                                  DWORD* age,
+                                                  std::string* pdbname) const {
   WinVMAddress nt_headers_address;
-  IMAGE_NT_HEADERS nt_headers;
+  NtHeadersType nt_headers;
   if (!ReadNtHeaders(&nt_headers_address, &nt_headers))
     return false;
 
   const IMAGE_DATA_DIRECTORY& data_directory =
       nt_headers.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_DEBUG];
   if (data_directory.VirtualAddress == 0 || data_directory.Size == 0)
     return false;
   IMAGE_DEBUG_DIRECTORY debug_directory;
   if (data_directory.Size % sizeof(debug_directory) != 0)
     return false;
@@ skipping 36 matching lines @@
     // This is a NUL-terminated string encoded in the codepage of the system
     // where the binary was linked. We have no idea what that was, so we just
     // assume ASCII.
     *pdbname = std::string(reinterpret_cast<char*>(&codeview->pdb_name[0]));
     return true;
   }
 
   return false;
 }
 
-// TODO(scottmg): This needs to be made cross-bitness supporting.
+template <class NtHeadersType>
 bool PEImageReader::ReadNtHeaders(WinVMAddress* nt_headers_address,
-                                  IMAGE_NT_HEADERS* nt_headers) const {
+                                  NtHeadersType* nt_headers) const {
   IMAGE_DOS_HEADER dos_header;
   if (!CheckedReadMemory(Address(), sizeof(IMAGE_DOS_HEADER), &dos_header)) {
     LOG(WARNING) << "could not read dos header of " << module_name_;
     return false;
   }
 
   if (dos_header.e_magic != IMAGE_DOS_SIGNATURE) {
     LOG(WARNING) << "invalid e_magic in dos header of " << module_name_;
     return false;
   }
 
   *nt_headers_address = Address() + dos_header.e_lfanew;
   if (!CheckedReadMemory(
-          *nt_headers_address, sizeof(IMAGE_NT_HEADERS), nt_headers)) {
+          *nt_headers_address, sizeof(NtHeadersType), nt_headers)) {
     LOG(WARNING) << "could not read nt headers of " << module_name_;
     return false;
   }
 
   if (nt_headers->Signature != IMAGE_NT_SIGNATURE) {
     LOG(WARNING) << "invalid signature in nt headers of " << module_name_;
     return false;
   }
 
   return true;
 }
 
+template <class NtHeadersType>
 bool PEImageReader::GetSectionByName(const std::string& name,
                                      IMAGE_SECTION_HEADER* section) const {
   if (name.size() > sizeof(section->Name)) {
     LOG(WARNING) << "supplied section name too long " << name;
     return false;
   }
 
   WinVMAddress nt_headers_address;
-  IMAGE_NT_HEADERS nt_headers;
+  NtHeadersType nt_headers;
   if (!ReadNtHeaders(&nt_headers_address, &nt_headers))
     return false;
 
   WinVMAddress first_section_address =
-      nt_headers_address + offsetof(IMAGE_NT_HEADERS, OptionalHeader) +
+      nt_headers_address + offsetof(NtHeadersType, OptionalHeader) +
       nt_headers.FileHeader.SizeOfOptionalHeader;
   for (DWORD i = 0; i < nt_headers.FileHeader.NumberOfSections; ++i) {
     WinVMAddress section_address =
         first_section_address + sizeof(IMAGE_SECTION_HEADER) * i;
     if (!CheckedReadMemory(
             section_address, sizeof(IMAGE_SECTION_HEADER), section)) {
       LOG(WARNING) << "could not read section " << i << " of " << module_name_;
       return false;
     }
     if (strncmp(reinterpret_cast<const char*>(section->Name),
@@ skipping 16 matching lines @@
   }
   if (!module_range_.ContainsRange(read_range)) {
     LOG(WARNING) << "attempt to read outside of module " << module_name_
                  << " at range: " << RangeToString(read_range);
     return false;
   }
   return process_reader_->ReadMemory(address, size, into);
 }
 
 }  // namespace crashpad