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1 // Copyright (c) 2011 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 <shlobj.h> | |
6 #include <shobjidl.h> | |
7 | |
8 #include "content/browser/safe_util_win.h" | |
9 | |
10 #include "base/files/file_path.h" | |
11 #include "base/logging.h" | |
12 #include "base/path_service.h" | |
13 #include "base/strings/string_util.h" | |
14 #include "base/strings/utf_string_conversions.h" | |
15 #include "base/win/scoped_comptr.h" | |
16 #include "ui/base/win/shell.h" | |
17 #include "url/gurl.h" | |
18 | |
19 namespace content { | |
20 namespace { | |
21 | |
22 // This GUID is associated with any 'don't ask me again' settings that the | |
23 // user can select for different file types. | |
24 // {2676A9A2-D919-4fee-9187-152100393AB2} | |
25 static const GUID kClientID = { 0x2676a9a2, 0xd919, 0x4fee, | |
26 { 0x91, 0x87, 0x15, 0x21, 0x0, 0x39, 0x3a, 0xb2 } }; | |
27 | |
28 // Sets the Zone Identifier on the file to "Internet" (3). Returns true if the | |
29 // function succeeds, false otherwise. A failure is expected on system where | |
30 // the Zone Identifier is not supported, like a machine with a FAT32 filesystem. | |
31 // This function does not invoke Windows Attachment Execution Services. | |
32 // | |
33 // |full_path| is the path to the downloaded file. | |
34 bool SetInternetZoneIdentifierDirectly(const base::FilePath& full_path) { | |
35 const DWORD kShare = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE; | |
36 std::wstring path = full_path.value() + L":Zone.Identifier"; | |
37 HANDLE file = CreateFile(path.c_str(), GENERIC_WRITE, kShare, NULL, | |
38 OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); | |
39 if (INVALID_HANDLE_VALUE == file) | |
40 return false; | |
41 | |
42 static const char kIdentifier[] = "[ZoneTransfer]\r\nZoneId=3\r\n"; | |
43 // Don't include trailing null in data written. | |
44 static const DWORD kIdentifierSize = arraysize(kIdentifier) - 1; | |
45 DWORD written = 0; | |
46 BOOL result = WriteFile(file, kIdentifier, kIdentifierSize, &written, NULL); | |
47 BOOL flush_result = FlushFileBuffers(file); | |
48 CloseHandle(file); | |
49 | |
50 if (!result || !flush_result || written != kIdentifierSize) { | |
51 NOTREACHED(); | |
52 return false; | |
53 } | |
54 | |
55 return true; | |
56 } | |
57 | |
58 } | |
59 | |
60 // This function implementation is based on the attachment execution | |
61 // services functionally deployed with IE6 or Service pack 2. This | |
62 // functionality is exposed in the IAttachmentExecute COM interface. | |
63 // more information at: | |
64 // http://msdn2.microsoft.com/en-us/library/ms647048.aspx | |
65 bool SaferOpenItemViaShell(HWND hwnd, const std::wstring& window_title, | |
66 const base::FilePath& full_path, | |
67 const std::wstring& source_url) { | |
68 base::win::ScopedComPtr<IAttachmentExecute> attachment_services; | |
69 HRESULT hr = attachment_services.CreateInstance(CLSID_AttachmentServices); | |
70 if (FAILED(hr)) { | |
71 // We don't have Attachment Execution Services, it must be a pre-XP.SP2 | |
72 // Windows installation, or the thread does not have COM initialized. | |
73 if (hr == CO_E_NOTINITIALIZED) { | |
74 NOTREACHED(); | |
75 return false; | |
76 } | |
77 return ui::win::OpenItemViaShell(full_path); | |
78 } | |
79 | |
80 attachment_services->SetClientGuid(kClientID); | |
81 | |
82 if (!window_title.empty()) | |
83 attachment_services->SetClientTitle(window_title.c_str()); | |
84 | |
85 // To help windows decide if the downloaded file is dangerous we can provide | |
86 // what the documentation calls evidence. Which we provide now: | |
87 // | |
88 // Set the file itself as evidence. | |
89 hr = attachment_services->SetLocalPath(full_path.value().c_str()); | |
90 if (FAILED(hr)) | |
91 return false; | |
92 // Set the origin URL as evidence. | |
93 hr = attachment_services->SetSource(source_url.c_str()); | |
94 if (FAILED(hr)) | |
95 return false; | |
96 | |
97 // Now check the windows policy. | |
98 if (attachment_services->CheckPolicy() != S_OK) { | |
99 // It is possible that the above call returns an undocumented result | |
100 // equal to 0x800c000e which seems to indicate that the URL failed the | |
101 // the security check. If you proceed with the Prompt() call the | |
102 // Shell might show a dialog that says: | |
103 // "windows found that this file is potentially harmful. To help protect | |
104 // your computer, Windows has blocked access to this file." | |
105 // Upon dismissal of the dialog windows will delete the file (!!). | |
106 // So, we can 'return' in that case but maybe is best to let it happen to | |
107 // fail on the safe side. | |
108 | |
109 ATTACHMENT_ACTION action; | |
110 // We cannot control what the prompt says or does directly but it | |
111 // is a pretty decent dialog; for example, if an executable is signed it can | |
112 // decode and show the publisher and the certificate. | |
113 hr = attachment_services->Prompt(hwnd, ATTACHMENT_PROMPT_EXEC, &action); | |
114 if (FAILED(hr) || (ATTACHMENT_ACTION_CANCEL == action)) { | |
115 // The user has declined opening the item. | |
116 return false; | |
117 } | |
118 } | |
119 return ui::win::OpenItemViaShellNoZoneCheck(full_path); | |
120 } | |
121 | |
122 HRESULT ScanAndSaveDownloadedFile(const base::FilePath& full_path, | |
123 const GURL& source_url) { | |
124 base::win::ScopedComPtr<IAttachmentExecute> attachment_services; | |
125 HRESULT hr = attachment_services.CreateInstance(CLSID_AttachmentServices); | |
126 | |
127 if (FAILED(hr)) { | |
128 // The thread must have COM initialized. | |
129 DCHECK_NE(CO_E_NOTINITIALIZED, hr); | |
130 | |
131 // We don't have Attachment Execution Services, it must be a pre-XP.SP2 | |
132 // Windows installation, or the thread does not have COM initialized. Try to | |
133 // set the zone information directly. Failure is not considered an error. | |
134 SetInternetZoneIdentifierDirectly(full_path); | |
135 return hr; | |
136 } | |
137 | |
138 hr = attachment_services->SetClientGuid(kClientID); | |
139 if (FAILED(hr)) | |
140 return hr; | |
141 | |
142 hr = attachment_services->SetLocalPath(full_path.value().c_str()); | |
143 if (FAILED(hr)) | |
144 return hr; | |
145 | |
146 hr = attachment_services->SetSource(UTF8ToWide(source_url.spec()).c_str()); | |
147 if (FAILED(hr)) | |
148 return hr; | |
149 | |
150 // A failure in the Save() call below could result in the downloaded file | |
151 // being deleted. | |
152 return attachment_services->Save(); | |
153 } | |
154 | |
155 } // namespace content | |
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