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
|
// Package ctlsock implements the control socket interface that can be
// activated by passing "-ctlsock" on the command line.
package ctlsock
import (
"encoding/json"
"errors"
"fmt"
"io"
"net"
"os"
"syscall"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
// Interface should be implemented by fusefrontend[_reverse]
type Interface interface {
EncryptPath(string) (string, error)
DecryptPath(string) (string, error)
}
// RequestStruct is sent by a client
type RequestStruct struct {
EncryptPath string
DecryptPath string
}
// ResponseStruct is sent by us as response to a request
type ResponseStruct struct {
// Result is the resulting decrypted or encrypted path. Empty on error.
Result string
// ErrNo is the error number as defined in errno.h.
// 0 means success and -1 means that the error number is not known
// (look at ErrText in this case).
ErrNo int32
// ErrText is a detailed error message.
ErrText string
// WarnText contains warnings that may have been encountered while
// processing the message.
WarnText string
}
type ctlSockHandler struct {
fs Interface
socket *net.UnixListener
}
// Serve serves incoming connections on "sock". This call blocks so you
// probably want to run it in a new goroutine.
func Serve(sock net.Listener, fs Interface) {
handler := ctlSockHandler{
fs: fs,
socket: sock.(*net.UnixListener),
}
handler.acceptLoop()
}
func (ch *ctlSockHandler) acceptLoop() {
for {
conn, err := ch.socket.Accept()
if err != nil {
// This can trigger on program exit with "use of closed network connection".
// Special-casing this is hard due to https://github.com/golang/go/issues/4373
// so just don't use tlog.Warn to not cause panics in the tests.
tlog.Info.Printf("ctlsock: Accept error: %v", err)
break
}
go ch.handleConnection(conn.(*net.UnixConn))
}
}
// ReadBufSize is the size of the request read buffer.
// The longest possible path is 4096 bytes on Linux and 1024 on Mac OS X so
// 5000 bytes should be enough to hold the whole JSON request. This
// assumes that the path does not contain too many characters that had to be
// be escaped in JSON (for example, a null byte blows up to "\u0000").
// We abort the connection if the request is bigger than this.
const ReadBufSize = 5000
// handleConnection reads and parses JSON requests from "conn"
func (ch *ctlSockHandler) handleConnection(conn *net.UnixConn) {
buf := make([]byte, ReadBufSize)
for {
n, err := conn.Read(buf)
if err == io.EOF {
conn.Close()
return
} else if err != nil {
tlog.Warn.Printf("ctlsock: Read error: %#v", err)
conn.Close()
return
}
if n == ReadBufSize {
tlog.Warn.Printf("ctlsock: request too big (max = %d bytes)", ReadBufSize-1)
conn.Close()
return
}
buf = buf[:n]
var in RequestStruct
err = json.Unmarshal(buf, &in)
if err != nil {
tlog.Warn.Printf("ctlsock: JSON Unmarshal error: %#v", err)
err = errors.New("JSON Unmarshal error: " + err.Error())
sendResponse(conn, err, "", "")
continue
}
ch.handleRequest(&in, conn)
// Restore original size.
buf = buf[:cap(buf)]
}
}
// handleRequest handles an already-unmarshaled JSON request
func (ch *ctlSockHandler) handleRequest(in *RequestStruct, conn *net.UnixConn) {
var err error
var inPath, outPath, clean, warnText string
// You cannot perform both decryption and encryption in one request
if in.DecryptPath != "" && in.EncryptPath != "" {
err = errors.New("Ambiguous")
sendResponse(conn, err, "", "")
return
}
// Neither encryption nor encryption has been requested, makes no sense
if in.DecryptPath == "" && in.EncryptPath == "" {
err = errors.New("Empty input")
sendResponse(conn, err, "", "")
return
}
// Canonicalize input path
if in.EncryptPath != "" {
inPath = in.EncryptPath
} else {
inPath = in.DecryptPath
}
clean = SanitizePath(inPath)
// Warn if a non-canonical path was passed
if inPath != clean {
warnText = fmt.Sprintf("Non-canonical input path '%s' has been interpreted as '%s'.", inPath, clean)
}
// Error out if the canonical path is now empty
if clean == "" {
err = errors.New("Empty input after canonicalization")
sendResponse(conn, err, "", warnText)
return
}
// Actual encrypt or decrypt operation
if in.EncryptPath != "" {
outPath, err = ch.fs.EncryptPath(clean)
} else {
outPath, err = ch.fs.DecryptPath(clean)
}
sendResponse(conn, err, outPath, warnText)
}
// sendResponse sends a JSON response message
func sendResponse(conn *net.UnixConn, err error, result string, warnText string) {
msg := ResponseStruct{
Result: result,
WarnText: warnText,
}
if err != nil {
msg.ErrText = err.Error()
msg.ErrNo = -1
// Try to extract the actual error number
if pe, ok := err.(*os.PathError); ok {
if se, ok := pe.Err.(syscall.Errno); ok {
msg.ErrNo = int32(se)
}
} else if err == syscall.ENOENT {
msg.ErrNo = int32(syscall.ENOENT)
}
}
jsonMsg, err := json.Marshal(msg)
if err != nil {
tlog.Warn.Printf("ctlsock: Marshal failed: %v", err)
return
}
// For convenience for the user, add a newline at the end.
jsonMsg = append(jsonMsg, '\n')
_, err = conn.Write(jsonMsg)
if err != nil {
tlog.Warn.Printf("ctlsock: Write failed: %v", err)
}
}
|
