win: Validate readability of memory ranges added to minidump

handler/win/self_destroying_test_program.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 <malloc.h>
+#include <windows.h>
+#include <winternl.h>
+
+#include "base/logging.h"
+#include "base/strings/stringprintf.h"
+#include "client/crashpad_client.h"
+#include "snapshot/win/process_reader_win.h"
+#include "tools/tool_support.h"
+
+namespace crashpad {
+namespace {
+
+// We VirtualFree a region in ourselves (the stack) to confirm that the
+// exception reporter captures as much as possible in the minidump and doesn't
+// abort. __debugbreak() immediately after doing so because the process is
+// clearly in a very broken state at this point.
+bool FreeOwnStackAndBreak() {
+  ProcessReaderWin process_reader;
+  if (!process_reader.Initialize(GetCurrentProcess(),
+                            ProcessSuspensionState::kRunning)) {

[Mark Mentovai, 2015/10/21 22:49:29]

Align

[scottmg, 2015/10/21 22:58:08]

Done.

+    LOG(ERROR) << "ProcessReaderWin Initialize";
+    return false;
+  }
+
+  const std::vector<ProcessReaderWin::Thread> threads =
+      process_reader.Threads();
+  if (threads.empty()) {
+    LOG(ERROR) << "no threads";
+    return false;
+  }
+
+  // Push the stack up a bit so that hopefully the crash handler can succeed,
+  // but won't be able to read the base of the stack.
+  _alloca(16384);
+
+  // We can't succeed at MEM_RELEASEing this memory, but MEM_DECOMMIT is good
+  // enough to make it inaccessible.
+  if (!VirtualFree(reinterpret_cast<void*>(threads[0].stack_region_address),
+                   100,
+                   MEM_DECOMMIT)) {
+    PLOG(ERROR) << "VirtualFree";
+    return false;
+  }
+
+  // If the VirtualFree() succeeds, we may have already crashed. __debugbreak()
+  // just to be sure.
+  __debugbreak();
+
+  return true;
+}
+
+int SelfDestroyingMain(int argc, char* argv[]) {
+  if (argc != 2) {
+    fprintf(stderr, "Usage: %s <server_pipe_name>\n", argv[0]);
+    return 1;

[Mark Mentovai, 2015/10/21 22:49:29]

<stdlib.h> EXIT_FAILURE, EXIT_SUCCESS

[scottmg, 2015/10/21 22:58:08]

Done.

+  }
+
+  CrashpadClient client;
+  if (!client.SetHandler(argv[1])) {
+    LOG(ERROR) << "SetHandler";
+    return 1;
+  }
+  if (!client.UseHandler()) {
+    LOG(ERROR) << "UseHandler";
+    return 1;
+  }
+
+  if (!FreeOwnStackAndBreak())
+    return 1;
+
+  return 0;

[Mark Mentovai, 2015/10/21 22:49:28]

Comment that this is not reached.

[scottmg, 2015/10/21 22:58:08]

Done.

+}
+
+}  // namespace
+}  // namespace crashpad
+
+int wmain(int argc, wchar_t* argv[]) {
+  return crashpad::ToolSupport::Wmain(argc, argv, crashpad::SelfDestroyingMain);
+}