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
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
#pragma once
#include <boost/process/async_pipe.hpp>
#include <boost/type_traits/has_dereference.hpp>
#include <cstring>
#include <filesystem>
#include <fstream>
#include <memory>
#include <string>
namespace fs = std::filesystem;
namespace utils
{
constexpr const size_t secretLimit = 1024;
template <typename T>
static void secureCleanup(T& value)
{
auto raw = const_cast<typename T::value_type*>(&value[0]);
explicit_bzero(raw, value.size() * sizeof(*raw));
}
class Credentials
{
public:
Credentials(std::string&& user, std::string&& password) :
userBuf(std::move(user)), passBuf(std::move(password))
{
}
~Credentials()
{
secureCleanup(userBuf);
secureCleanup(passBuf);
}
const std::string& user()
{
return userBuf;
}
const std::string& password()
{
return passBuf;
}
private:
Credentials() = delete;
Credentials(const Credentials&) = delete;
Credentials& operator=(const Credentials&) = delete;
std::string userBuf;
std::string passBuf;
};
class CredentialsProvider
{
public:
template <typename T>
struct Deleter
{
void operator()(T* buff) const
{
if (buff)
{
secureCleanup(*buff);
delete buff;
}
}
};
using Buffer = std::vector<char>;
using SecureBuffer = std::unique_ptr<Buffer, Deleter<Buffer>>;
// Using explicit definition instead of std::function to avoid implicit
// conversions eg. stack copy instead of reference for parameters
using FormatterFunc = void(const std::string& username,
const std::string& password, Buffer& dest);
CredentialsProvider(std::string&& user, std::string&& password) :
credentials(std::move(user), std::move(password))
{
}
const std::string& user()
{
return credentials.user();
}
const std::string& password()
{
return credentials.password();
}
SecureBuffer pack(const FormatterFunc formatter)
{
SecureBuffer packed{new Buffer{}};
if (formatter)
{
formatter(credentials.user(), credentials.password(), *packed);
}
return packed;
}
private:
Credentials credentials;
};
// Wrapper for boost::async_pipe ensuring proper pipe cleanup
template <typename Buffer>
class NamedPipe
{
public:
using unix_fd = sdbusplus::message::unix_fd;
NamedPipe(boost::asio::io_context& io, const std::string name,
Buffer&& buffer) :
name(name),
impl(io, name), buffer{std::move(buffer)}
{
}
~NamedPipe()
{
// Named pipe needs to be explicitly removed
impl.close();
::unlink(name.c_str());
}
unix_fd fd()
{
return unix_fd{impl.native_sink()};
}
const std::string& file()
{
return name;
}
template <typename WriteHandler>
void async_write(WriteHandler&& handler)
{
impl.async_write_some(data(), std::forward<WriteHandler>(handler));
}
private:
// Specialization for pointer types
template <typename B = Buffer>
typename std::enable_if<boost::has_dereference<B>::value,
boost::asio::const_buffer>::type
data()
{
return boost::asio::buffer(*buffer);
}
template <typename B = Buffer>
typename std::enable_if<!boost::has_dereference<B>::value,
boost::asio::const_buffer>::type
data()
{
return boost::asio::buffer(buffer);
}
const std::string name;
boost::process::async_pipe impl;
Buffer buffer;
};
class VolatileFile
{
using Buffer = CredentialsProvider::SecureBuffer;
public:
VolatileFile(Buffer&& contents) :
filePath(fs::temp_directory_path() / std::tmpnam(nullptr)),
size(contents->size())
{
auto data = std::move(contents);
create(filePath, data);
}
~VolatileFile()
{
// Purge file contents
std::array<char, secretLimit> buf;
buf.fill('*');
std::ofstream file(filePath);
std::size_t bytesWritten = 0, bytesToWrite = 0;
while (bytesWritten < size)
{
bytesToWrite = std::min(secretLimit, (size - bytesWritten));
file.write(buf.data(), bytesToWrite);
bytesWritten += bytesToWrite;
}
// Remove leftover file
fs::remove(filePath);
}
const std::string& path()
{
return filePath;
}
private:
static void create(const std::string& filePath, const Buffer& data)
{
// Create file
std::ofstream file(filePath);
// Limit permissions to owner only
fs::permissions(filePath,
fs::perms::owner_read | fs::perms::owner_write,
fs::perm_options::replace);
// Write contents
file.write(data->data(), data->size());
}
const std::string filePath;
const std::size_t size;
};
} // namespace utils
|
