forked from owenthereal/upterm
/
sshhandler.go
196 lines (166 loc) · 4.49 KB
/
sshhandler.go
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
package server
import (
"io"
"net"
"sync"
"github.com/gliderlabs/ssh"
"github.com/oklog/run"
log "github.com/sirupsen/logrus"
gossh "golang.org/x/crypto/ssh"
)
const (
forwardedStreamlocalChannelType = "forwarded-streamlocal@openssh.com"
streamlocalForwardChannelType = "streamlocal-forward@openssh.com"
cancelStreamlocalForwardChannelType = "cancel-streamlocal-forward@openssh.com"
)
type streamlocalChannelForwardMsg struct {
SocketPath string
}
type forwardedStreamlocalPayload struct {
SocketPath string
Reserved0 string
}
func newStreamlocalForwardHandler(
sessionRepo *sessionRepo,
sessionDialListener SessionDialListener,
logger log.FieldLogger,
) *streamlocalForwardHandler {
return &streamlocalForwardHandler{
sessionRepo: sessionRepo,
sessionDialListener: sessionDialListener,
forwards: make(map[string]net.Listener),
logger: logger,
}
}
type streamlocalForwardHandler struct {
sessionRepo *sessionRepo
sessionDialListener SessionDialListener
forwards map[string]net.Listener
logger log.FieldLogger
sync.Mutex
}
func (h *streamlocalForwardHandler) listen(ctx ssh.Context, ln net.Listener, sessionID string, logger log.FieldLogger) error {
conn := ctx.Value(ssh.ContextKeyConn).(*gossh.ServerConn)
for {
c, err := ln.Accept()
if err != nil {
return err
}
go func(sessionID string, logger log.FieldLogger) {
payload := gossh.Marshal(&forwardedStreamlocalPayload{
SocketPath: sessionID,
})
ch, reqs, err := conn.OpenChannel(forwardedStreamlocalChannelType, payload)
if err != nil {
logger.WithError(err).Error("error opening channel")
c.Close()
return
}
closeAll := func() {
ch.Close()
c.Close()
}
var g run.Group
{
g.Add(func() error {
gossh.DiscardRequests(reqs)
return nil
}, func(err error) {
closeAll()
})
}
{
g.Add(func() error {
_, err := io.Copy(ch, c)
return err
}, func(err error) {
closeAll()
})
}
{
g.Add(func() error {
_, err := io.Copy(c, ch)
return err
}, func(err error) {
closeAll()
})
}
if err := g.Run(); err != nil {
logger.WithError(err).Error("error listening connection")
}
}(sessionID, logger)
}
}
func (h *streamlocalForwardHandler) Handler(ctx ssh.Context, srv *ssh.Server, req *gossh.Request) (bool, []byte) {
switch req.Type {
case streamlocalForwardChannelType:
var reqPayload streamlocalChannelForwardMsg
if err := gossh.Unmarshal(req.Payload, &reqPayload); err != nil {
h.logger.WithError(err).Error("error parsing streamlocal payload")
return false, []byte(err.Error())
}
if srv.ReversePortForwardingCallback == nil || !srv.ReversePortForwardingCallback(ctx, reqPayload.SocketPath, 0) {
return false, []byte("port forwarding is disabled")
}
sessionID := reqPayload.SocketPath
logger := h.logger.WithFields(log.Fields{"session-id": sessionID})
// validate session exists
if _, err := h.sessionRepo.Get(sessionID); err != nil {
return false, []byte(err.Error())
}
ln, err := h.sessionDialListener.Listen(sessionID)
if err != nil {
logger.WithError(err).Error("error listening socketing")
return false, []byte(err.Error())
}
h.trackListener(sessionID, ln)
var g run.Group
{
g.Add(func() error {
<-ctx.Done()
return ctx.Err()
}, func(err error) {
h.closeListener(sessionID)
})
}
{
g.Add(func() error {
return h.listen(ctx, ln, sessionID, logger)
}, func(err error) {
h.closeListener(sessionID)
})
}
go func(sessionID string) {
if err := g.Run(); err != nil {
h.logger.WithError(err).WithField("session-id", sessionID).Debug("error handling ssh session")
}
}(sessionID)
return true, nil
case cancelStreamlocalForwardChannelType:
var reqPayload streamlocalChannelForwardMsg
if err := gossh.Unmarshal(req.Payload, &reqPayload); err != nil {
h.logger.WithError(err).Error("error parsing steamlocal payload")
return false, []byte(err.Error())
}
sessionID := reqPayload.SocketPath
h.closeListener(sessionID)
return true, nil
default:
return false, nil
}
}
func (h *streamlocalForwardHandler) trackListener(sessionID string, ln net.Listener) {
h.Lock()
defer h.Unlock()
h.forwards[sessionID] = ln
}
func (h *streamlocalForwardHandler) closeListener(sessionID string) {
h.Lock()
defer h.Unlock()
ln, ok := h.forwards[sessionID]
if ok {
ln.Close()
}
delete(h.forwards, sessionID)
h.sessionRepo.Delete(sessionID)
}