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// Copyright 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#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
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