win: Add more memory regions to gathering of PEB

snapshot/win/process_snapshot_win.cc

Index: snapshot/win/process_snapshot_win.cc
diff --git a/snapshot/win/process_snapshot_win.cc b/snapshot/win/process_snapshot_win.cc
index b9df62c0ab4c011109ab9054f5b556141958d658..ad660978df8c4011eea1952e7a682cd41e4094b6 100644
--- a/snapshot/win/process_snapshot_win.cc
+++ b/snapshot/win/process_snapshot_win.cc
@@ -14,7 +14,10 @@
 
 #include "snapshot/win/process_snapshot_win.h"
 
+#include <algorithm>
+
 #include "base/logging.h"
+#include "base/strings/stringprintf.h"
 #include "snapshot/win/module_snapshot_win.h"
 #include "util/win/registration_protocol_win.h"
 #include "util/win/time.h"
@@ -48,10 +51,11 @@ bool ProcessSnapshotWin::Initialize(HANDLE process,
     return false;
 
   system_.Initialize(&process_reader_);
-  WinVMAddress peb_address;
-  WinVMSize peb_size;
-  process_reader_.GetProcessInfo().Peb(&peb_address, &peb_size);
-  peb_.Initialize(&process_reader_, peb_address, peb_size);
+
+  if (process_reader_.Is64Bit())
+    InitializePebData<process_types::internal::Traits64>();
+  else
+    InitializePebData<process_types::internal::Traits32>();
 
   InitializeThreads();
   InitializeModules();
@@ -186,7 +190,8 @@ const ExceptionSnapshot* ProcessSnapshotWin::Exception() const {
 std::vector<const MemorySnapshot*> ProcessSnapshotWin::ExtraMemory() const {
   INITIALIZATION_STATE_DCHECK_VALID(initialized_);
   std::vector<const MemorySnapshot*> extra_memory;
-  extra_memory.push_back(&peb_);
+  for (const auto& peb_memory : peb_memory_)
+    extra_memory.push_back(peb_memory);
   return extra_memory;
 }
 
@@ -214,4 +219,167 @@ void ProcessSnapshotWin::InitializeModules() {
   }
 }
 
+template <class Traits>
+void ProcessSnapshotWin::InitializePebData() {
+  WinVMAddress peb_address;
+  WinVMSize peb_size;
+  process_reader_.GetProcessInfo().Peb(&peb_address, &peb_size);
+  AddMemorySnapshot(peb_address, peb_size, &peb_memory_);
+
+  process_types::PEB<Traits> peb_data;
+  if (!process_reader_.ReadMemory(peb_address, peb_size, &peb_data)) {
+    LOG(ERROR) << "ReadMemory PEB";
+    return;
+  }
+
+  process_types::PEB_LDR_DATA<Traits> peb_ldr_data;
+  AddMemorySnapshot(peb_data.Ldr, sizeof(peb_ldr_data), &peb_memory_);
+  if (!process_reader_.ReadMemory(
+          peb_data.Ldr, sizeof(peb_ldr_data), &peb_ldr_data)) {
+    LOG(ERROR) << "ReadMemory PEB_LDR_DATA";
+  } else {
+    // Walk the LDR structure to retrieve its pointed-to data.
+    AddMemorySnapshotForLdrLIST_ENTRY(
+        peb_ldr_data.InLoadOrderModuleList,
+        offsetof(process_types::LDR_DATA_TABLE_ENTRY<Traits>, InLoadOrderLinks),
+        &peb_memory_);
+    AddMemorySnapshotForLdrLIST_ENTRY(
+        peb_ldr_data.InMemoryOrderModuleList,
+        offsetof(process_types::LDR_DATA_TABLE_ENTRY<Traits>,
+                 InMemoryOrderLinks),
+        &peb_memory_);
+    AddMemorySnapshotForLdrLIST_ENTRY(
+        peb_ldr_data.InInitializationOrderModuleList,
+        offsetof(process_types::LDR_DATA_TABLE_ENTRY<Traits>,
+                 InInitializationOrderLinks),
+        &peb_memory_);
+  }
+
+  process_types::RTL_USER_PROCESS_PARAMETERS<Traits> process_parameters;
+  if (!process_reader_.ReadMemory(peb_data.ProcessParameters,
+                                  sizeof(process_parameters),
+                                  &process_parameters)) {
+    LOG(ERROR) << "ReadMemory RTL_USER_PROCESS_PARAMETERS";
+    return;
+  }
+  AddMemorySnapshot(
+      peb_data.ProcessParameters, sizeof(process_parameters), &peb_memory_);
+
+  AddMemorySnapshotForUNICODE_STRING(
+      process_parameters.CurrentDirectory.DosPath, &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.DllPath, &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.ImagePathName,
+                                     &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.CommandLine,
+                                     &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.WindowTitle,
+                                     &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.DesktopInfo,
+                                     &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.ShellInfo,
+                                     &peb_memory_);
+  AddMemorySnapshotForUNICODE_STRING(process_parameters.RuntimeData,
+                                     &peb_memory_);
+  AddMemorySnapshot(
+      process_parameters.Environment,
+      DetermineSizeOfEnvironmentBlock(process_parameters.Environment),
+      &peb_memory_);
+}
+
+void ProcessSnapshotWin::AddMemorySnapshot(
+    WinVMAddress address,
+    WinVMSize size,
+    PointerVector<internal::MemorySnapshotWin>* into) {
+  if (size == 0)
+    return;
+
+  // Ensure that the entire range is readable. TODO(scottmg): Consider
+  // generalizing this as part of
+  // https://code.google.com/p/crashpad/issues/detail?id=59.
+  auto ranges = process_reader_.GetProcessInfo().GetReadableRanges(
+      CheckedRange<WinVMAddress, WinVMSize>(address, size));
+  if (ranges.size() != 1) {
+    LOG(ERROR) << base::StringPrintf(
+        "range at 0x%llx, size 0x%llx fully unreadable", address, size);
+    return;
+  }
+  if (ranges[0].base() != address || ranges[0].size() != size) {
+    LOG(ERROR) << base::StringPrintf(
+        "some of range at 0x%llx, size 0x%llx unreadable", address, size);
+    return;
+  }
+
+  // If we have already added this exact range, don't add it again. This is
+  // useful for the LDR module lists which are a set of doubly-linked lists, all
+  // pointing to the same module name strings.
+  // TODO(scottmg): A more general version of this, handling overlapping,
+  // contained, etc. https://code.google.com/p/crashpad/issues/detail?id=61.
+  for (const auto& ms : *into) {

[Mark Mentovai, 2015/10/01 22:00:52]

ms is a little bit too abbreviated for an “auto” that doesn’t say the actual
type name. Can we go with memory_snapshot even if it means that it’ll be +1
line?

[scottmg, 2015/10/01 22:05:57]

Done.

+    if (ms->Address() == address && ms->Size() == size)
+      return;
+  }
+
+  internal::MemorySnapshotWin* memory_snapshot =
+      new internal::MemorySnapshotWin();
+  memory_snapshot->Initialize(&process_reader_, address, size);
+  into->push_back(memory_snapshot);
+}
+
+template <class Traits>
+void ProcessSnapshotWin::AddMemorySnapshotForUNICODE_STRING(
+    const process_types::UNICODE_STRING<Traits>& us,
+    PointerVector<internal::MemorySnapshotWin>* into) {
+  AddMemorySnapshot(us.Buffer, us.Length, into);
+}
+
+template <class Traits>
+void ProcessSnapshotWin::AddMemorySnapshotForLdrLIST_ENTRY(
+      const process_types::LIST_ENTRY<Traits>& le, size_t offset_of_member,
+      PointerVector<internal::MemorySnapshotWin>* into) {
+  // Walk the doubly-linked list of entries, adding the list memory itself, as
+  // well as pointed-to strings.
+  Traits::Pointer last = le.Blink;
+  process_types::LDR_DATA_TABLE_ENTRY<Traits> entry;
+  Traits::Pointer cur = le.Flink;
+  for (;;) {
+    // |cur| is the pointer to LIST_ENTRY embedded in the LDR_DATA_TABLE_ENTRY.
+    // So we need to offset back to the beginning of the structure.
+    if (!process_reader_.ReadMemory(
+            cur - offset_of_member, sizeof(entry), &entry)) {
+      return;
+    }
+    AddMemorySnapshot(cur - offset_of_member, sizeof(entry), into);
+    AddMemorySnapshotForUNICODE_STRING(entry.FullDllName, into);
+    AddMemorySnapshotForUNICODE_STRING(entry.BaseDllName, into);
+
+    process_types::LIST_ENTRY<Traits>* links =
+        reinterpret_cast<process_types::LIST_ENTRY<Traits>*>(
+            reinterpret_cast<unsigned char*>(&entry) + offset_of_member);
+    cur = links->Flink;
+    if (cur == last)
+      break;
+  }
+}
+
+WinVMSize ProcessSnapshotWin::DetermineSizeOfEnvironmentBlock(
+    WinVMAddress start_of_environment_block) {
+  // http://blogs.msdn.com/b/oldnewthing/archive/2010/02/03/9957320.aspx On
+  // newer OSs there's no stated limit, but in practice grabbing 32k characters
+  // should be more than enough.
+  std::wstring env_block;
+  env_block.resize(32768);
+  WinVMSize bytes_read = process_reader_.ReadAvailableMemory(
+      start_of_environment_block,
+      env_block.size() * sizeof(env_block[0]),
+      &env_block[0]);
+  env_block.resize(
+      static_cast<unsigned int>(bytes_read / sizeof(env_block[0])));
+  const wchar_t terminator[] = { 0, 0 };
+  size_t at = env_block.find(std::wstring(terminator, arraysize(terminator)));
+  if (at != std::wstring::npos)
+    env_block.resize(at + arraysize(terminator));
+
+  return env_block.size() * sizeof(env_block[0]);
+}
+
 }  // namespace crashpad