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
|
package encoder
import (
"bytes"
"crypto/rand"
"encoding/base64"
"encoding/binary"
"encoding/hex"
"os"
"strings"
"testing"
"golang.org/x/crypto/nacl/box"
)
func testKeyring(t *testing.T) string {
t.Helper()
path := t.TempDir() + "/pubring.mix"
var content strings.Builder
for i, name := range []string{"entry", "middle", "exit"} {
keyID := strings.Repeat(string(rune('a'+i)), 32)
publicKey := strings.Repeat(string(rune('d'+i)), 64)
content.WriteString(name + " " + name + "@example.org " + keyID + " 4:0.2c E 2025-01-01 2099-12-31\n\n")
content.WriteString("-----Begin Mix Key-----\n" + keyID + "\n" + publicKey + "\n-----End Mix Key-----\n")
}
if err := os.WriteFile(path, []byte(content.String()), 0600); err != nil {
t.Fatal(err)
}
return path
}
func TestValidateEmail(t *testing.T) {
r := Request{Kind: Email, PublicKeyring: "/tmp/pubring.mix", Entry: "entry", Chain: []string{"entry"}, To: "user@example.org", Body: "hello"}
if err := Validate(r); err != nil {
t.Fatal(err)
}
}
func TestValidateRejectsPlainIncompleteRequest(t *testing.T) {
r := Request{Kind: Email, PublicKeyring: "/tmp/pubring.mix", Entry: "entry", Chain: []string{"entry"}, To: "bad", Body: "hello"}
if err := Validate(r); err == nil {
t.Fatal("expected invalid recipient")
}
}
func TestValidateUsenetRequiresGatewayRecipient(t *testing.T) {
r := Request{Kind: Usenet, PublicKeyring: "/tmp/pubring.mix", Chain: []string{"entry"}, Newsgroup: "misc.test", Body: "hello"}
if err := Validate(r); err == nil {
t.Fatal("expected missing Usenet gateway recipient to be rejected")
}
r.To = "mail2news@example.org"
if err := Validate(r); err != nil {
t.Fatalf("expected valid Usenet request: %v", err)
}
}
func TestComposeUsenetGatewayHeaders(t *testing.T) {
plain, err := composeMessage(Request{
Kind: Usenet, To: "mail2news@example.org", Subject: "test", Newsgroup: "misc.test", Body: "hello",
})
if err != nil {
t.Fatal(err)
}
text := string(plain)
if !strings.Contains(text, "To: mail2news@example.org\n") || !strings.Contains(text, "Newsgroups: misc.test\n") {
t.Fatalf("missing Usenet delivery headers: %q", text)
}
}
func TestEncodeProducesYAMNArmor(t *testing.T) {
keyring := testKeyring(t)
result, err := Encode(Request{
Kind: Email, PublicKeyring: keyring, Entry: "entry", Chain: []string{"entry"},
From: "Anonymous <anon@example.org>", To: "user@example.org", Subject: "test", Body: "hello",
})
if err != nil {
t.Fatal(err)
}
if result.EntryAddress != "entry@example.org" {
t.Fatalf("unexpected entry address: %q", result.EntryAddress)
}
text := string(result.Envelope)
if !strings.Contains(text, "-----BEGIN REMAILER MESSAGE-----") || !strings.Contains(text, "-----END REMAILER MESSAGE-----") {
t.Fatal("missing YAMN armor markers")
}
lines := strings.Split(text, "\n")
start := 0
for i, line := range lines {
if line == "-----BEGIN REMAILER MESSAGE-----" {
start = i + 3
break
}
}
var encoded strings.Builder
for _, line := range lines[start:] {
if line == "" || strings.HasPrefix(line, "-----END") {
break
}
encoded.WriteString(line)
}
packet, err := base64.StdEncoding.DecodeString(encoded.String())
if err != nil {
t.Fatal(err)
}
if len(packet) != messageBytes {
t.Fatalf("unexpected packet size: got %d, want %d", len(packet), messageBytes)
}
}
func TestEncodeMultiHop(t *testing.T) {
result, err := Encode(Request{
Kind: Email, PublicKeyring: testKeyring(t), Entry: "entry",
Chain: []string{"entry", "middle", "exit"}, To: "user@example.org", Body: "hello",
})
if err != nil {
t.Fatal(err)
}
if len(result.Envelope) == 0 || result.EntryAddress != "entry@example.org" {
t.Fatal("multi-hop envelope was not produced")
}
}
func TestEncodeMultiHopDecodesAtEveryRemailer(t *testing.T) {
keyring, secretKeys := testDecodeKeyring(t)
request := Request{
Kind: Email, PublicKeyring: keyring, Entry: "entry",
Chain: []string{"entry", "middle", "exit"}, From: "Anonymous <anon@example.org>",
To: "user@example.org", Subject: "three-hop compatibility", Body: "hello through three remailers",
}
result, err := Encode(request)
if err != nil {
t.Fatal(err)
}
packet := decodeArmoredPacket(t, result.Envelope)
wantPlain, err := composeMessage(request)
if err != nil {
t.Fatal(err)
}
for hop, name := range request.Chain {
data := openHeaderForTest(t, packet[:headerBytes], secretKeys[name])
if data[0] != 2 {
t.Fatalf("hop %d (%s): unexpected packet version %d", hop, name, data[0])
}
if !bytes.Equal(data[117:149], antiTag(packet)) {
t.Fatalf("hop %d (%s): anti-tag mismatch", hop, name)
}
switch data[1] {
case 0:
if hop == len(request.Chain)-1 {
t.Fatalf("hop %d (%s): exit encoded as intermediate", hop, name)
}
shiftHeadersUpForTest(packet)
encryptAll(packet, data[19:51], data[53:65])
case 1:
if hop != len(request.Chain)-1 {
t.Fatalf("hop %d (%s): intermediate encoded as exit", hop, name)
}
bodyLength := int(binary.LittleEndian.Uint32(data[87:91]))
if bodyLength != len(wantPlain) {
t.Fatalf("exit body length: got %d, want %d", bodyLength, len(wantPlain))
}
body := aesCTR(packet[maxChainLength*headerBytes:], data[19:51], data[53:69])
if !bytes.Equal(body[:bodyLength], wantPlain) {
t.Fatal("exit plaintext does not match the encoded message")
}
default:
t.Fatalf("hop %d (%s): unknown packet type %d", hop, name, data[1])
}
}
}
func testDecodeKeyring(t *testing.T) (string, map[string]*[32]byte) {
t.Helper()
path := t.TempDir() + "/pubring.mix"
secretKeys := make(map[string]*[32]byte)
var content strings.Builder
for i, name := range []string{"entry", "middle", "exit"} {
publicKey, secretKey, err := box.GenerateKey(rand.Reader)
if err != nil {
t.Fatal(err)
}
keyID := bytes.Repeat([]byte{byte(i + 1)}, 16)
content.WriteString(name + " " + name + "@example.org " + hex.EncodeToString(keyID) + " 4:0.2c E 2025-01-01 2099-12-31\n\n")
content.WriteString("-----Begin Mix Key-----\n" + hex.EncodeToString(keyID) + "\n" + hex.EncodeToString(publicKey[:]) + "\n-----End Mix Key-----\n")
secretKeys[name] = secretKey
}
if err := os.WriteFile(path, []byte(content.String()), 0600); err != nil {
t.Fatal(err)
}
return path, secretKeys
}
func decodeArmoredPacket(t *testing.T, envelope []byte) []byte {
t.Helper()
lines := strings.Split(string(envelope), "\n")
start := -1
for i, line := range lines {
if line == "-----BEGIN REMAILER MESSAGE-----" {
start = i + 3
break
}
}
if start < 0 {
t.Fatal("missing armored packet start")
}
var encoded strings.Builder
for _, line := range lines[start:] {
if line == "" || strings.HasPrefix(line, "-----END") {
break
}
encoded.WriteString(line)
}
packet, err := base64.StdEncoding.DecodeString(encoded.String())
if err != nil {
t.Fatal(err)
}
if len(packet) != messageBytes {
t.Fatalf("unexpected packet size: got %d, want %d", len(packet), messageBytes)
}
return packet
}
func openHeaderForTest(t *testing.T, header []byte, recipientSecret *[32]byte) []byte {
t.Helper()
var senderPublic [32]byte
copy(senderPublic[:], header[16:48])
var nonce [24]byte
copy(nonce[:], header[48:72])
data, ok := box.Open(nil, header[72:248], &nonce, &senderPublic, recipientSecret)
if !ok {
t.Fatal("header authentication failed")
}
if len(data) != encHeadBytes {
t.Fatalf("unexpected decoded header size: got %d, want %d", len(data), encHeadBytes)
}
return data
}
func shiftHeadersUpForTest(packet []byte) {
headersEnd := maxChainLength * headerBytes
copy(packet, packet[headerBytes:headersEnd])
clear(packet[headersEnd-headerBytes : headersEnd])
}
|
