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
|
// Copyright (c) 2006-2008 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/browser/ie7_password.h"
#include <wincrypt.h>
#include <string>
#include <vector>
#include "base/logging.h"
#include "base/scoped_ptr.h"
#include "base/string_util.h"
namespace {
// Structures that IE7/IE8 use to store a username/password.
// Some of the fields might have been incorrectly reverse engineered.
struct PreHeader {
DWORD pre_header_size; // Size of this header structure. Always 12.
DWORD header_size; // Size of the real Header: sizeof(Header) +
// item_count * sizeof(Entry);
DWORD data_size; // Size of the data referenced by the entries.
};
struct Header {
char wick[4]; // The string "WICK". I don't know what it means.
DWORD fixed_header_size; // The size of this structure without the entries:
// sizeof(Header).
DWORD item_count; // Number of entries. It should always be 2. One for
// the username, and one for the password.
wchar_t two_letters[2]; // Two unknown bytes.
DWORD unknown[2]; // Two unknown DWORDs.
};
struct Entry {
DWORD offset; // Offset where the data referenced by this entry is
// located.
FILETIME time_stamp; // Timestamp when the password got added.
DWORD string_length; // The length of the data string.
};
// Main data structure.
struct PasswordEntry {
PreHeader pre_header; // Contains the size of the different sections.
Header header; // Contains the number of items.
Entry entry[1]; // List of entries containing a string. The first one
// is the username, the second one if the password.
};
// Cleans up a crypt prov and a crypt hash.
void CleanupHashContext(HCRYPTPROV prov, HCRYPTHASH hash) {
if (hash)
CryptDestroyHash(hash);
if (prov)
CryptReleaseContext(prov, 0);
}
} // namespace
namespace ie7_password {
bool GetUserPassFromData(const std::vector<unsigned char>& data,
std::wstring* username,
std::wstring* password) {
const PasswordEntry* information =
reinterpret_cast<const PasswordEntry*>(&data.front());
// Some expected values. If it's not what we expect we don't even try to
// understand the data.
if (information->pre_header.pre_header_size != sizeof(PreHeader))
return false;
if (information->header.item_count != 2) // Username and Password
return false;
if (information->header.fixed_header_size != sizeof(Header))
return false;
const uint8* ptr = &data.front();
const uint8* offset_to_data = ptr + information->pre_header.header_size +
information->pre_header.pre_header_size;
const Entry* user_entry = information->entry;
const Entry* pass_entry = user_entry+1;
*username = reinterpret_cast<const wchar_t*>(offset_to_data +
user_entry->offset);
*password = reinterpret_cast<const wchar_t*>(offset_to_data +
pass_entry->offset);
return true;
}
std::wstring GetUrlHash(const std::wstring& url) {
HCRYPTPROV prov = NULL;
HCRYPTHASH hash = NULL;
std::wstring lower_case_url = StringToLowerASCII(url);
BOOL result = CryptAcquireContext(&prov, 0, 0, PROV_RSA_FULL, 0);
if (!result) {
if (GetLastError() == NTE_BAD_KEYSET) {
// The keyset does not exist. Create one.
result = CryptAcquireContext(&prov, 0, 0, PROV_RSA_FULL, CRYPT_NEWKEYSET);
}
}
if (!result) {
DCHECK(false);
return std::wstring();
}
// Initialize the hash.
if (!CryptCreateHash(prov, CALG_SHA1, 0, 0, &hash)) {
CleanupHashContext(prov, hash);
DCHECK(false);
return std::wstring();
}
// Add the data to the hash.
const unsigned char* buffer =
reinterpret_cast<const unsigned char*>(lower_case_url.c_str());
DWORD data_len = static_cast<DWORD>((lower_case_url.size() + 1) *
sizeof(wchar_t));
if (!CryptHashData(hash, buffer, data_len, 0)) {
CleanupHashContext(prov, hash);
DCHECK(false);
return std::wstring();
}
// Get the size of the resulting hash.
DWORD hash_len = 0;
DWORD buffer_size = sizeof(hash_len);
if (!CryptGetHashParam(hash, HP_HASHSIZE,
reinterpret_cast<unsigned char*>(&hash_len),
&buffer_size, 0)) {
CleanupHashContext(prov, hash);
DCHECK(false);
return std::wstring();
}
// Get the hash data.
scoped_array<unsigned char> new_buffer(new unsigned char[hash_len]);
if (!CryptGetHashParam(hash, HP_HASHVAL, new_buffer.get(), &hash_len, 0)) {
CleanupHashContext(prov, hash);
DCHECK(false);
return std::wstring();
}
std::wstring url_hash;
// Transform the buffer to an hexadecimal string.
unsigned char checksum = 0;
for (DWORD i = 0; i < hash_len; ++i) {
checksum += new_buffer.get()[i];
url_hash += StringPrintf(L"%2.2X", new_buffer.get()[i]);
}
url_hash += StringPrintf(L"%2.2X", checksum);
CleanupHashContext(prov, hash);
return url_hash;
}
bool DecryptPassword(const std::wstring& url,
const std::vector<unsigned char>& data,
std::wstring* username, std::wstring* password) {
std::wstring lower_case_url = StringToLowerASCII(url);
DATA_BLOB input = {0};
DATA_BLOB output = {0};
DATA_BLOB url_key = {0};
input.pbData = const_cast<unsigned char*>(&data.front());
input.cbData = static_cast<DWORD>((data.size()) *
sizeof(std::string::value_type));
url_key.pbData = reinterpret_cast<unsigned char*>(
const_cast<wchar_t*>(lower_case_url.data()));
url_key.cbData = static_cast<DWORD>((lower_case_url.size() + 1) *
sizeof(std::wstring::value_type));
if (CryptUnprotectData(&input, NULL, &url_key, NULL, NULL,
CRYPTPROTECT_UI_FORBIDDEN, &output)) {
// Now that we have the decrypted information, we need to understand it.
std::vector<unsigned char> decrypted_data;
decrypted_data.resize(output.cbData);
memcpy(&decrypted_data.front(), output.pbData, output.cbData);
GetUserPassFromData(decrypted_data, username, password);
LocalFree(output.pbData);
return true;
}
return false;
}
} // namespace ie7_password
|
