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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 
21 namespace sandbox {
22 
NamedPipeDispatcher(PolicyBase * policy_base)23 NamedPipeDispatcher::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 
SetupService(InterceptionManager * manager,int service)34 bool 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 
CreateNamedPipe(IPCInfo * ipc,base::string16 * name,DWORD open_mode,DWORD pipe_mode,DWORD max_instances,DWORD out_buffer_size,DWORD in_buffer_size,DWORD default_timeout)43 bool 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