Get module versions and types from in-memory images

snapshot/win/pe_image_resource_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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "snapshot/win/pe_image_resource_reader.h"
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace crashpad {
+
+PEImageResourceReader::PEImageResourceReader()
+    : process_reader_(nullptr),
+      resources_range_(),
+      module_base_(0),
+      module_name_(),
+      initialized_() {
+}
+
+PEImageResourceReader::~PEImageResourceReader() {
+}
+
+bool PEImageResourceReader::Initialize(
+    ProcessReaderWin* process_reader,
+    const IMAGE_DATA_DIRECTORY& resources_directory_entry,
+    const CheckedWinAddressRange& module_range,
+    std::string module_name) {
+  INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
+
+  process_reader_ = process_reader;
+
+  resources_range_.SetRange(
+      process_reader_->Is64Bit(),
+      module_range.Base() + resources_directory_entry.VirtualAddress,
+      resources_directory_entry.Size);
+  if (!resources_range_.IsValid()) {
+    LOG(WARNING) << "invalid resources range " << resources_range_.AsString()
+                 << " for " << module_name;
+    return false;
+  }
+
+  if (!module_range.ContainsRange(resources_range_)) {
+    LOG(WARNING) << "resources range " << resources_range_.AsString()
+                 << " outside of module range " << module_range.AsString()
+                 << " for " << module_name;
+    return false;
+  }
+
+  module_base_ = module_range.Base();
+  module_name_ = module_name;
+
+  INITIALIZATION_STATE_SET_VALID(initialized_);
+  return true;
+}
+
+bool PEImageResourceReader::FindResourceByID(uint16_t type,
+                                             uint16_t name,
+                                             uint16_t language,
+                                             WinVMAddress* address,
+                                             WinVMSize* size,
+                                             uint32_t* code_page) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  // The root resource directory is at the beginning of the resources area
+  // within the module.
+  const uint32_t name_directory_offset =
+      GetEntryFromResourceDirectoryByID(0, type, true);
+  if (!name_directory_offset) {
+    return false;
+  }
+
+  const uint32_t language_directory_offset =
+      GetEntryFromResourceDirectoryByID(name_directory_offset, name, true);
+  if (!language_directory_offset) {
+    return false;
+  }
+
+  // The definition of IMAGE_RESOURCE_DIRECTORY_ENTRY in <winnt.h> has a comment
+  // saying that its offsets are relative to “the resource directory of the data
+  // associated with this directory entry”. That could be interpreted to mean
+  // that language_directory_offset is relative to name_directory_offset, since
+  // the language directory entry is found within the name directory. This is
+  // not correct. All resource offsets are relative to the resources area within
+  // the module.
+  const uint32_t data_offset = GetEntryFromResourceDirectoryByLanguage(
+      language_directory_offset, language);
+  if (!data_offset) {
+    return false;
+  }
+
+  IMAGE_RESOURCE_DATA_ENTRY data_entry;
+  if (!CheckedReadMemory(resources_range_.Base() + data_offset,
+                         sizeof(data_entry),
+                         &data_entry)) {
+    return false;
+  }
+
+  // The definition of IMAGE_RESOURCE_DATA_ENTRY in <winnt.h> has a comment
+  // saying that OffsetToData is relative to the beginning of the resource data.
+  // This is not correct. It’s module-relative.
+  *address = module_base_ + data_entry.OffsetToData;
+  *size = data_entry.Size;
+  if (code_page) {
+    *code_page = data_entry.CodePage;
+  }
+
+  return true;
+}
+
+uint32_t PEImageResourceReader::GetEntryFromResourceDirectoryByID(
+    uint32_t language_directory_offset,
+    uint16_t id,
+    bool want_subdirectory) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  std::vector<IMAGE_RESOURCE_DIRECTORY_ENTRY> entries_by_id;
+  if (!ReadResourceDirectory(
+          language_directory_offset, nullptr, nullptr, &entries_by_id)) {
+    return 0;
+  }
+
+  for (const auto& entry : entries_by_id) {
+    if (!entry.NameIsString && entry.Id == id) {
+      if (static_cast<bool>(entry.DataIsDirectory) != want_subdirectory) {
+        LOG(WARNING) << "expected " << (want_subdirectory ? "" : "non-")
+                     << "directory for entry id " << id << " in "
+                     << module_name_;
+        return 0;
+      }
+
+      return entry.DataIsDirectory ? entry.OffsetToDirectory

[scottmg, 2015/11/26 21:30:00]

The != above warns but this one doesn't? Silly.

[Mark Mentovai, 2015/11/27 17:56:28]

scottmg wrote:
What do you mean? It’s allowed to be a directory or a non-directory here.

[scottmg, 2015/11/27 18:06:58]

Sorry, I just meant that there wasn't a need to
static_cast<bool>(entry.DataIsDirectory) here. I was assuming the cast above was
to suppress a warning.

Nothing to do here.

[Mark Mentovai, 2015/11/27 21:40:37]

scottmg wrote:
Oh compiler warning, yeah. That C4800 “performance warning” is pretty bogus and
inconsistent.

+                                   : entry.OffsetToData;
+    }
+  }
+
+  return 0;
+}
+
+uint32_t PEImageResourceReader::GetEntryFromResourceDirectoryByLanguage(
+    uint32_t resource_directory_offset,
+    uint16_t language) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  std::vector<IMAGE_RESOURCE_DIRECTORY_ENTRY> entries_by_language;
+  if (!ReadResourceDirectory(
+          resource_directory_offset, nullptr, nullptr, &entries_by_language)) {
+    return 0;
+  }
+
+  if (entries_by_language.empty()) {
+    return 0;
+  }
+
+  // https://msdn.microsoft.com/en-us/library/cc194810.aspx
+  //
+  // TODO(mark): It seems like the FindResourceEx() might do something more

[scottmg, 2015/11/26 21:30:00]

Remove "the ".

[Mark Mentovai, 2015/12/01 18:48:01]

scottmg wrote:
Done.

+  // complex. It would be best to mimic its behavior.
+  std::vector<uint16_t> try_languages;
+  try_languages.push_back(language);
+  try_languages.push_back(MAKELANGID(PRIMARYLANGID(language), SUBLANG_NEUTRAL));
+  try_languages.push_back(MAKELANGID(LANG_NEUTRAL, SUBLANG_NEUTRAL));
+  try_languages.push_back(MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT));

[scottmg, 2015/11/26 21:30:00]

Presumably this should be the UI language rather than LANG_ENGLISH.

I wondered about adding LANG_INVARIANT here (just based on its name), but I see
little documentation about it, and I don't really know what it is.

I mucked around in windbg for a while, and I think the similar functionality is
happening in ntdll!LdrpSearchResourceSection_U which looks substantially more
complicated than this. I think there's probably a variety of more other things
it tries in the language == 0 case.

But I think the fallback of first entry is realistically fine for our purposes,
so I don't know that it's important that we do anything extra here.

[Mark Mentovai, 2015/12/01 18:48:01]

scottmg wrote:
I changed this up a little bit, but I still don‘t think it totally matches what
Windows does. But it’s closer.

If the language is neutral, it tries the languages from the thread/user/system
locales up front. The hard-coded English fallback down here is intentional. It’s
what the document referenced above says, it’s in ReactOS too, and it matches the
only language found in MS-shipped DLLs like kernel32. (And I doubt that there
are language-specific kernel32s out there, but maybe I’m wrong.)

What the code does now is kind of like ReactOS, but slightly different. There’s
no way to specify that you want to get a resource of
LANG_NEUTRAL/SUBLANG_NEUTRAL as a first choice, but that’s how FindResourceEx()
works too.

+
+  for (const auto try_language : try_languages) {
+    for (const auto& entry : entries_by_language) {
+      if (!entry.NameIsString && entry.Id == try_language) {
+        if (entry.DataIsDirectory) {
+          LOG(WARNING) << "expected non-directory for entry language "
+                       << try_language << " in " << module_name_;
+          return 0;
+        }
+
+        return entry.OffsetToData;
+      }
+    }
+  }
+
+  // Fall back to the first entry in the list.
+  const auto& entry = entries_by_language.front();
+  if (entry.DataIsDirectory) {
+    LOG(WARNING) << "expected non-directory for entry in " << module_name_;
+    return 0;
+  }
+
+  return entry.OffsetToData;
+}
+
+bool PEImageResourceReader::ReadResourceDirectory(
+    uint32_t resource_directory_offset,
+    IMAGE_RESOURCE_DIRECTORY* resource_directory,
+    std::vector<IMAGE_RESOURCE_DIRECTORY_ENTRY>* named_entries,
+    std::vector<IMAGE_RESOURCE_DIRECTORY_ENTRY>* id_entries) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  // resource_directory is optional, but it’s still needed locally even if the
+  // caller isn’t interested in it.
+  scoped_ptr<IMAGE_RESOURCE_DIRECTORY> local_resource_directory;
+  if (!resource_directory) {
+    local_resource_directory.reset(new IMAGE_RESOURCE_DIRECTORY);
+    resource_directory = local_resource_directory.get();
+  }
+
+  const WinVMAddress address =
+      resources_range_.Base() + resource_directory_offset;
+
+  if (!CheckedReadMemory(
+          address, sizeof(*resource_directory), resource_directory)) {
+    LOG(WARNING) << "could not read resource directory";
+    return false;
+  }
+
+  if (named_entries) {
+    named_entries->clear();
+    named_entries->resize(resource_directory->NumberOfNamedEntries);
+    if (!named_entries->empty() &&
+        !CheckedReadMemory(address + sizeof(*resource_directory),
+                           named_entries->size() * sizeof((*named_entries)[0]),
+                           &(*named_entries)[0])) {
+      LOG(WARNING) << "could not read resource directory named entries";
+      return false;
+    }
+  }
+
+  if (id_entries) {
+    id_entries->clear();
+    id_entries->resize(resource_directory->NumberOfIdEntries);
+    if (!id_entries->empty() &&
+        !CheckedReadMemory(address + sizeof(*resource_directory) +
+                               resource_directory->NumberOfNamedEntries *
+                                   sizeof((*named_entries)[0]),

[scottmg, 2015/11/26 21:30:00]

Just confirming that this is OK when named_entries is null, right?

[Mark Mentovai, 2015/12/01 18:48:01]

scottmg wrote:
I changed it to the type name to avoid problems with overzealous runtime
analysis like ubsan. I’m not saying that ubsan or something else of its ilk
would hate this, just that I can’t say that it’s “definitely OK”.

+                           id_entries->size() * sizeof((*id_entries)[0]),
+                           &(*id_entries)[0])) {
+      LOG(WARNING) << "could not read resource directory ID entries";
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool PEImageResourceReader::CheckedReadMemory(WinVMAddress address,

[scottmg, 2015/11/26 21:30:00]

Can we avoid duplicating this here and in PEImageReader?

[Mark Mentovai, 2015/12/01 18:48:01]

scottmg wrote:
Done.

+                                              WinVMSize size,
+                                              void* into) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  CheckedWinAddressRange read_range(process_reader_->Is64Bit(), address, size);
+  if (!read_range.IsValid()) {
+    LOG(WARNING) << "invalid read range: " << read_range.AsString();
+    return false;
+  }
+  if (!resources_range_.ContainsRange(read_range)) {
+    LOG(WARNING) << "attempt to read outside of module " << module_name_
+                 << " resources at range: " << read_range.AsString();
+    return false;
+  }
+  return process_reader_->ReadMemory(address, size, into);
+}
+
+}  // namespace crashpad