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
|
package submit
import (
"context"
"crypto/rand"
"crypto/sha256"
"encoding/base64"
"encoding/hex"
"fmt"
"net/mail"
"os"
"os/exec"
"regexp"
"strings"
"time"
)
var messageIDRE = regexp.MustCompile(`^<[^<>\s]+@[^<>\s]+>$`)
func BuildMessage(sub Submission, recipient, messageIDDomain, identiconsCLI string, requireFace bool) (raw string, messageID string, err error) {
messageID, err = newMessageID(messageIDDomain)
if err != nil {
return "", "", err
}
headers := []string{
"From: " + sub.From,
"To: " + recipient,
"Subject: " + sub.Subject,
"Message-ID: " + messageID,
"Date: " + jitteredDate(),
"Newsgroups: " + strings.Join(sub.Newsgroups, ","),
"X-Ed25519-Pub: " + sub.PublicKeyB64,
"X-Ed25519-Sig: " + sub.SignatureB64,
}
face := faceHeader(sub, identiconsCLI)
if face == "" && requireFace {
return "", "", fmt.Errorf("face header generation failed")
}
if face != "" {
headers = append(headers, "Face: "+face)
}
if refs := normalizeReferences(sub.References); refs != "" {
headers = append(headers, "References: "+refs, "In-Reply-To: "+refs)
}
headers = append(headers,
"MIME-Version: 1.0",
"Content-Type: text/plain; charset=utf-8",
"Content-Transfer-Encoding: 8bit",
"User-Agent: n2usenet-https-nym/0.1",
"X-No-Archive: Yes",
)
return strings.Join(headers, "\r\n") + "\r\n\r\n" + sub.Message, messageID, nil
}
func newMessageID(domain string) (string, error) {
domain = cleanHeader(domain)
if domain == "" {
domain = "n2usenet.local"
}
var b [16]byte
if _, err := rand.Read(b[:]); err != nil {
return "", err
}
return fmt.Sprintf("<%s.%d@%s>", hex.EncodeToString(b[:]), time.Now().Unix(), domain), nil
}
func jitteredDate() string {
var b [2]byte
if _, err := rand.Read(b[:]); err != nil {
return time.Now().UTC().Format(time.RFC1123Z)
}
seconds := int(b[0])<<8 | int(b[1])
seconds = seconds%3601 - 1800
return time.Now().UTC().Add(time.Duration(seconds) * time.Second).Format(time.RFC1123Z)
}
func normalizeReferences(refs string) string {
refs = cleanHeader(refs)
if refs == "" {
return ""
}
if !strings.HasPrefix(refs, "<") {
refs = "<" + refs
}
if !strings.HasSuffix(refs, ">") {
refs += ">"
}
if !messageIDRE.MatchString(refs) {
return ""
}
return refs
}
type FaceIdentity struct {
Hash string `json:"hash"`
Face string `json:"face"`
Preview string `json:"preview"`
}
func GenerateFace(username, email, pubkeyB64, identiconsCLI string, size int) (FaceIdentity, error) {
if identiconsCLI == "" {
return FaceIdentity{}, fmt.Errorf("identicons cli not configured")
}
if st, err := os.Stat(identiconsCLI); err != nil || st.IsDir() || st.Mode()&0111 == 0 {
return FaceIdentity{}, fmt.Errorf("identicons cli not executable")
}
username = cleanHeader(username)
email = cleanHeader(email)
pubkeyB64 = strings.TrimSpace(pubkeyB64)
if username == "" || email == "" || strings.ContainsAny(username, "|") || strings.ContainsAny(email, "|") {
return FaceIdentity{}, fmt.Errorf("invalid identity fields")
}
if _, err := base64.StdEncoding.DecodeString(pubkeyB64); err != nil {
return FaceIdentity{}, fmt.Errorf("invalid public key")
}
if size <= 0 {
size = 48
}
input := username + "|" + email + "|" + pubkeyB64
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
defer cancel()
out, err := exec.CommandContext(ctx, identiconsCLI, "-input", input, "-size", fmt.Sprintf("%d", size), "-transparent", "-format", "base64").Output()
if err != nil {
return FaceIdentity{}, fmt.Errorf("identicons cli failed: %w", err)
}
face := strings.TrimSpace(string(out))
if _, err := base64.StdEncoding.DecodeString(face); err != nil {
return FaceIdentity{}, fmt.Errorf("invalid face output")
}
hash := sha256.Sum256([]byte(input))
return FaceIdentity{
Hash: hex.EncodeToString(hash[:]),
Face: face,
Preview: "data:image/png;base64," + face,
}, nil
}
func faceHeader(sub Submission, identiconsCLI string) string {
addr, err := mail.ParseAddress(sub.From)
if err != nil {
return ""
}
face, err := GenerateFace(addr.Name, addr.Address, sub.PublicKeyB64, identiconsCLI, 48)
if err != nil {
return ""
}
return face.Face
}
|
