1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome_frame/chrome_launcher.h"
#include <windows.h>
#include <shellapi.h>
#include <shlwapi.h>
// Herein lies stuff selectively stolen from Chrome. We don't pull it in
// directly because all of it results in many things we don't want being
// included as well.
namespace {
// These are the switches we will allow (along with their values) in the
// safe-for-Low-Integrity version of the Chrome command line.
// Including the chrome switch files pulls in a bunch of dependencies sadly, so
// we redefine things here:
const wchar_t* kAllowedSwitches[] = {
L"automation-channel",
L"chrome-frame",
L"chrome-version",
L"disable-renderer-accessibility",
L"enable-experimental-extension-apis",
L"force-renderer-accessibility",
L"lang",
L"no-default-browser-check",
L"noerrdialogs",
L"no-first-run",
L"user-data-dir",
L"disable-popup-blocking",
L"full-memory-crash-report",
};
const wchar_t kWhitespaceChars[] = {
0x0009, /* <control-0009> to <control-000D> */
0x000A,
0x000B,
0x000C,
0x000D,
0x0020, /* Space */
0x0085, /* <control-0085> */
0x00A0, /* No-Break Space */
0x1680, /* Ogham Space Mark */
0x180E, /* Mongolian Vowel Separator */
0x2000, /* En Quad to Hair Space */
0x2001,
0x2002,
0x2003,
0x2004,
0x2005,
0x2006,
0x2007,
0x2008,
0x2009,
0x200A,
0x200C, /* Zero Width Non-Joiner */
0x2028, /* Line Separator */
0x2029, /* Paragraph Separator */
0x202F, /* Narrow No-Break Space */
0x205F, /* Medium Mathematical Space */
0x3000, /* Ideographic Space */
0
};
const wchar_t kLauncherExeBaseName[] = L"chrome_launcher.exe";
const wchar_t kBrowserProcessExecutableName[] = L"chrome.exe";
} // end namespace
namespace chrome_launcher {
std::wstring TrimWhiteSpace(const wchar_t* input_str) {
std::wstring output;
if (input_str != NULL) {
std::wstring str(input_str);
const std::wstring::size_type first_good_char =
str.find_first_not_of(kWhitespaceChars);
const std::wstring::size_type last_good_char =
str.find_last_not_of(kWhitespaceChars);
if (first_good_char != std::wstring::npos &&
last_good_char != std::wstring::npos &&
last_good_char >= first_good_char) {
// + 1 because find_last_not_of returns the index, and we want the count
output = str.substr(first_good_char,
last_good_char - first_good_char + 1);
}
}
return output;
}
bool IsValidArgument(const std::wstring& arg) {
if (arg.length() < 2) {
return false;
}
for (int i = 0; i < arraysize(kAllowedSwitches); ++i) {
size_t arg_length = lstrlenW(kAllowedSwitches[i]);
if (arg.find(kAllowedSwitches[i], 2) == 2) {
// The argument starts off right, now it must either end here, or be
// followed by an equals sign.
if (arg.length() == (arg_length + 2) ||
(arg.length() > (arg_length + 2) && arg[arg_length+2] == L'=')) {
return true;
}
}
}
return false;
}
bool IsValidCommandLine(const wchar_t* command_line) {
if (command_line == NULL) {
return false;
}
int num_args = 0;
wchar_t** args = NULL;
args = CommandLineToArgvW(command_line, &num_args);
bool success = true;
// Note that we skip args[0] since that is just our executable name and
// doesn't get passed through to Chrome.
for (int i = 1; i < num_args; ++i) {
std::wstring trimmed_arg = TrimWhiteSpace(args[i]);
if (!IsValidArgument(trimmed_arg.c_str())) {
success = false;
break;
}
}
return success;
}
bool SanitizeAndLaunchChrome(const wchar_t* command_line) {
bool success = false;
if (IsValidCommandLine(command_line)) {
std::wstring chrome_path;
if (GetChromeExecutablePath(&chrome_path)) {
const wchar_t* args = PathGetArgs(command_line);
// Build the command line string with the quoted path to chrome.exe.
std::wstring command_line;
command_line.reserve(chrome_path.size() + 2);
command_line.append(1, L'\"').append(chrome_path).append(1, L'\"');
if (args != NULL) {
command_line += L' ';
command_line += args;
}
STARTUPINFO startup_info = {0};
startup_info.cb = sizeof(startup_info);
startup_info.dwFlags = STARTF_USESHOWWINDOW;
startup_info.wShowWindow = SW_SHOW;
PROCESS_INFORMATION process_info = {0};
if (CreateProcess(&chrome_path[0], &command_line[0],
NULL, NULL, FALSE, 0, NULL, NULL,
&startup_info, &process_info)) {
// Close handles.
CloseHandle(process_info.hThread);
CloseHandle(process_info.hProcess);
success = true;
} else {
_ASSERT(FALSE);
}
}
}
return success;
}
bool GetChromeExecutablePath(std::wstring* chrome_path) {
_ASSERT(chrome_path);
wchar_t cur_path[MAX_PATH * 4] = {0};
// Assume that we are always built into an exe.
GetModuleFileName(NULL, cur_path, arraysize(cur_path) / 2);
PathRemoveFileSpec(cur_path);
bool success = false;
if (PathAppend(cur_path, kBrowserProcessExecutableName)) {
if (!PathFileExists(cur_path)) {
// The installation model for Chrome places the DLLs in a versioned
// sub-folder one down from the Chrome executable. If we fail to find
// chrome.exe in the current path, try looking one up and launching that
// instead. In practice, that means we back up two and append the
// executable name again.
PathRemoveFileSpec(cur_path);
PathRemoveFileSpec(cur_path);
PathAppend(cur_path, kBrowserProcessExecutableName);
}
if (PathFileExists(cur_path)) {
*chrome_path = cur_path;
success = true;
}
}
return success;
}
} // namespace chrome_launcher
|
