win: make CrashpadInfo retrievable

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,
+// 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_reader.h"
+
+#include <string.h>
+
+#include "base/logging.h"
+#include "base/strings/stringprintf.h"
+#include "client/crashpad_info.h"
+#include "snapshot/win/process_reader_win.h"
+
+namespace crashpad {
+
+namespace {
+
+std::string RangeToString(const CheckedWinAddressRange& range) {
+  return base::StringPrintf("[0x%llx + 0x%llx (%s)]",
+                            range.Base(),
+                            range.Size(),
+                            range.Is64Bit() ? "64" : "32");
+}
+
+}  // namespace
+
+PEImageReader::PEImageReader()
+    : process_reader_(nullptr),
+      address_(0),
+      size_(0),
+      module_range_(),
+      module_name_(),
+      initialized_() {
+}
+
+PEImageReader::~PEImageReader() {
+}
+
+bool PEImageReader::Initialize(ProcessReaderWin* process_reader,
+                               win_vm_address_t address,
+                               win_vm_size_t size,
+                               const std::string& module_name) {
+  INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
+
+  process_reader_ = process_reader;
+  address_ = address;

[Mark Mentovai, 2015/05/01 19:05:31]

Do you need distinct fields for address_ and size_? They’re already tracked in
module_range_.

[scottmg, 2015/05/01 19:46:31]

Done.

+  size_ = size;
+  module_range_.SetRange(process_reader_->Is64Bit(), address_, size_);
+  if (!module_range_.IsValid()) {
+    LOG(WARNING) << "invalid module range for " << module_name << ": "
+                 << RangeToString(module_range_);
+    return false;
+  }
+  module_name_ = module_name;
+
+  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 (section.Misc.VirtualSize < sizeof(process_types::CrashpadInfo)) {
+    LOG(WARNING) << "small crashpad info section size "
+                 << section.Misc.VirtualSize << ", " << module_name_;
+    return false;
+  }
+
+  win_vm_address_t crashpad_info_address = address_ + section.VirtualAddress;
+  CheckedWinAddressRange crashpad_info_range(process_reader_->Is64Bit(),
+                                             crashpad_info_address,
+                                             section.Misc.VirtualSize);
+  if (!crashpad_info_range.IsValid()) {
+    LOG(WARNING) << "invalid range for crashpad info: "
+                 << RangeToString(crashpad_info_range);
+    return false;
+  }
+
+  if (!module_range_.ContainsRange(crashpad_info_range)) {
+    LOG(WARNING) << "crashpad info does not fall inside module "
+                 << module_name_;
+    return false;
+  }
+
+  // TODO(scottmg): process_types for cross-bitness.
+  if (!process_reader_->ReadMemory(crashpad_info_address,
+                                   sizeof(process_types::CrashpadInfo),
+                                   crashpad_info)) {
+    LOG(WARNING) << "could not read crashpad info " << module_name_;
+    return false;
+  }
+
+  if (crashpad_info->signature != CrashpadInfo::kSignature ||
+      crashpad_info->version < 1) {
+    LOG(WARNING) << "unexpected crashpad info data " << module_name_;
+    return false;
+  }
+
+  return true;
+}
+
+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;
+  }
+
+  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;
+  }
+
+  // TODO(scottmg): This is reading a same-bitness sized structure.
+  IMAGE_NT_HEADERS nt_headers;
+  win_vm_address_t nt_headers_address = address_ + dos_header.e_lfanew;
+  if (!CheckedReadMemory(
+          nt_headers_address, sizeof(IMAGE_NT_HEADERS), &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;
+  }
+
+  win_vm_address_t first_section_address =
+      nt_headers_address + offsetof(IMAGE_NT_HEADERS, OptionalHeader) +
+      nt_headers.FileHeader.SizeOfOptionalHeader;
+  for (DWORD i = 0; i < nt_headers.FileHeader.NumberOfSections; ++i) {
+    win_vm_address_t 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),
+                name.c_str(),
+                sizeof(section->Name)) == 0) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool PEImageReader::CheckedReadMemory(win_vm_address_t address,
+                                      win_vm_size_t size,
+                                      void* into) const {
+  CheckedWinAddressRange read_range(process_reader_->Is64Bit(), address, size);
+  if (!read_range.IsValid()) {
+    LOG(WARNING) << "invalid read range: " << RangeToString(read_range);
+    return false;
+  }
+  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