1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "sandbox/win/src/named_pipe_dispatcher.h"
6
7#include "base/basictypes.h"
8#include "base/strings/string_split.h"
9
10#include "sandbox/win/src/crosscall_client.h"
11#include "sandbox/win/src/interception.h"
12#include "sandbox/win/src/interceptors.h"
13#include "sandbox/win/src/ipc_tags.h"
14#include "sandbox/win/src/named_pipe_interception.h"
15#include "sandbox/win/src/named_pipe_policy.h"
16#include "sandbox/win/src/policy_broker.h"
17#include "sandbox/win/src/policy_params.h"
18#include "sandbox/win/src/sandbox.h"
19
20
21namespace sandbox {
22
23NamedPipeDispatcher::NamedPipeDispatcher(PolicyBase* policy_base)
24    : policy_base_(policy_base) {
25  static const IPCCall create_params = {
26    {IPC_CREATENAMEDPIPEW_TAG, WCHAR_TYPE, ULONG_TYPE, ULONG_TYPE, ULONG_TYPE,
27     ULONG_TYPE, ULONG_TYPE, ULONG_TYPE},
28    reinterpret_cast<CallbackGeneric>(&NamedPipeDispatcher::CreateNamedPipe)
29  };
30
31  ipc_calls_.push_back(create_params);
32}
33
34bool NamedPipeDispatcher::SetupService(InterceptionManager* manager,
35                                       int service) {
36  if (IPC_CREATENAMEDPIPEW_TAG == service)
37    return INTERCEPT_EAT(manager, kKerneldllName, CreateNamedPipeW,
38                         CREATE_NAMED_PIPE_ID, 36);
39
40  return false;
41}
42
43bool NamedPipeDispatcher::CreateNamedPipe(
44    IPCInfo* ipc, base::string16* name, DWORD open_mode, DWORD pipe_mode,
45    DWORD max_instances, DWORD out_buffer_size, DWORD in_buffer_size,
46    DWORD default_timeout) {
47  ipc->return_info.win32_result = ERROR_ACCESS_DENIED;
48  ipc->return_info.handle = INVALID_HANDLE_VALUE;
49
50  std::vector<base::string16> paths;
51  std::vector<base::string16> innerpaths;
52  base::SplitString(*name, '/', &paths);
53
54  for (std::vector<base::string16>::const_iterator iter = paths.begin();
55       iter != paths.end(); ++iter) {
56    base::SplitString(*iter, '\\', &innerpaths);
57    for (std::vector<base::string16>::const_iterator iter2 = innerpaths.begin();
58         iter2 != innerpaths.end(); ++iter2) {
59      if (*iter2 == L"..")
60        return true;
61    }
62  }
63
64  const wchar_t* pipe_name = name->c_str();
65  CountedParameterSet<NameBased> params;
66  params[NameBased::NAME] = ParamPickerMake(pipe_name);
67
68  EvalResult eval = policy_base_->EvalPolicy(IPC_CREATENAMEDPIPEW_TAG,
69                                             params.GetBase());
70
71  // "For file I/O, the "\\?\" prefix to a path string tells the Windows APIs to
72  // disable all string parsing and to send the string that follows it straight
73  // to the file system."
74  // http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx
75  // This ensures even if there is a path traversal in the pipe name, and it is
76  // able to get past the checks above, it will still not be allowed to escape
77  // our whitelisted namespace.
78  if (name->compare(0, 4, L"\\\\.\\") == 0)
79    name->replace(0, 4, L"\\\\\?\\");
80
81  HANDLE pipe;
82  DWORD ret = NamedPipePolicy::CreateNamedPipeAction(eval, *ipc->client_info,
83                                                     *name, open_mode,
84                                                     pipe_mode, max_instances,
85                                                     out_buffer_size,
86                                                     in_buffer_size,
87                                                     default_timeout, &pipe);
88
89  ipc->return_info.win32_result = ret;
90  ipc->return_info.handle = pipe;
91  return true;
92}
93
94}  // namespace sandbox
95