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
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
|
package dbus
import (
"bufio"
"bytes"
"errors"
"io"
"os"
"strconv"
)
// AuthStatus represents the Status of an authentication mechanism.
type AuthStatus byte
const (
// AuthOk signals that authentication is finished; the next command
// from the server should be an OK.
AuthOk AuthStatus = iota
// AuthContinue signals that additional data is needed; the next command
// from the server should be a DATA.
AuthContinue
// AuthError signals an error; the server sent invalid data or some
// other unexpected thing happened and the current authentication
// process should be aborted.
AuthError
)
type authState byte
const (
waitingForData authState = iota
waitingForOk
waitingForReject
)
// Auth defines the behaviour of an authentication mechanism.
type Auth interface {
// Return the name of the mechanism, the argument to the first AUTH command
// and the next status.
FirstData() (name, resp []byte, status AuthStatus)
// Process the given DATA command, and return the argument to the DATA
// command and the next status. If len(resp) == 0, no DATA command is sent.
HandleData(data []byte) (resp []byte, status AuthStatus)
}
// Auth authenticates the connection, trying the given list of authentication
// mechanisms (in that order). If nil is passed, the EXTERNAL and
// DBUS_COOKIE_SHA1 mechanisms are tried for the current user. For private
// connections, this method must be called before sending any messages to the
// bus. Auth must not be called on shared connections.
func (conn *Conn) Auth(methods []Auth) error {
if methods == nil {
uid := strconv.Itoa(os.Getuid())
methods = []Auth{AuthExternal(uid), AuthCookieSha1(uid, getHomeDir())}
}
in := bufio.NewReader(conn.transport)
err := conn.transport.SendNullByte()
if err != nil {
return err
}
err = authWriteLine(conn.transport, []byte("AUTH"))
if err != nil {
return err
}
s, err := authReadLine(in)
if err != nil {
return err
}
if len(s) < 2 || !bytes.Equal(s[0], []byte("REJECTED")) {
return errors.New("dbus: authentication protocol error")
}
s = s[1:]
for _, v := range s {
for _, m := range methods {
if name, _, status := m.FirstData(); bytes.Equal(v, name) {
var ok bool
err = authWriteLine(conn.transport, []byte("AUTH"), v)
if err != nil {
return err
}
switch status {
case AuthOk:
err, ok = conn.tryAuth(m, waitingForOk, in)
case AuthContinue:
err, ok = conn.tryAuth(m, waitingForData, in)
default:
panic("dbus: invalid authentication status")
}
if err != nil {
return err
}
if ok {
if conn.transport.SupportsUnixFDs() {
err = authWriteLine(conn, []byte("NEGOTIATE_UNIX_FD"))
if err != nil {
return err
}
line, err := authReadLine(in)
if err != nil {
return err
}
switch {
case bytes.Equal(line[0], []byte("AGREE_UNIX_FD")):
conn.EnableUnixFDs()
conn.unixFD = true
case bytes.Equal(line[0], []byte("ERROR")):
default:
return errors.New("dbus: authentication protocol error")
}
}
err = authWriteLine(conn.transport, []byte("BEGIN"))
if err != nil {
return err
}
go conn.inWorker()
return nil
}
}
}
}
return errors.New("dbus: authentication failed")
}
// tryAuth tries to authenticate with m as the mechanism, using state as the
// initial authState and in for reading input. It returns (nil, true) on
// success, (nil, false) on a REJECTED and (someErr, false) if some other
// error occurred.
func (conn *Conn) tryAuth(m Auth, state authState, in *bufio.Reader) (error, bool) {
for {
s, err := authReadLine(in)
if err != nil {
return err, false
}
switch {
case state == waitingForData && string(s[0]) == "DATA":
if len(s) != 2 {
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
continue
}
data, status := m.HandleData(s[1])
switch status {
case AuthOk, AuthContinue:
if len(data) != 0 {
err = authWriteLine(conn.transport, []byte("DATA"), data)
if err != nil {
return err, false
}
}
if status == AuthOk {
state = waitingForOk
}
case AuthError:
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
}
case state == waitingForData && string(s[0]) == "REJECTED":
return nil, false
case state == waitingForData && string(s[0]) == "ERROR":
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
case state == waitingForData && string(s[0]) == "OK":
if len(s) != 2 {
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
}
conn.uuid = string(s[1])
return nil, true
case state == waitingForData:
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
case state == waitingForOk && string(s[0]) == "OK":
if len(s) != 2 {
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
}
conn.uuid = string(s[1])
return nil, true
case state == waitingForOk && string(s[0]) == "DATA":
err = authWriteLine(conn.transport, []byte("DATA"))
if err != nil {
return err, false
}
case state == waitingForOk && string(s[0]) == "REJECTED":
return nil, false
case state == waitingForOk && string(s[0]) == "ERROR":
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
case state == waitingForOk:
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
case state == waitingForReject && string(s[0]) == "REJECTED":
return nil, false
case state == waitingForReject:
return errors.New("dbus: authentication protocol error"), false
default:
panic("dbus: invalid auth state")
}
}
}
// authReadLine reads a line and separates it into its fields.
func authReadLine(in *bufio.Reader) ([][]byte, error) {
data, err := in.ReadBytes('\n')
if err != nil {
return nil, err
}
data = bytes.TrimSuffix(data, []byte("\r\n"))
return bytes.Split(data, []byte{' '}), nil
}
// authWriteLine writes the given line in the authentication protocol format
// (elements of data separated by a " " and terminated by "\r\n").
func authWriteLine(out io.Writer, data ...[]byte) error {
buf := make([]byte, 0)
for i, v := range data {
buf = append(buf, v...)
if i != len(data)-1 {
buf = append(buf, ' ')
}
}
buf = append(buf, '\r')
buf = append(buf, '\n')
n, err := out.Write(buf)
if err != nil {
return err
}
if n != len(buf) {
return io.ErrUnexpectedEOF
}
return nil
}
|
