agentbbs/internal/mailbox/smtp_test.go
Anthony Ettinger 55d517feb4 fix(mailbox): verify SMTP STARTTLS against the mail host, not the dial IP
AgentMail compose/send failed with 'cannot validate certificate for 127.0.0.1
because it doesn't contain any IP SANs': the sender dialed the local relay at
127.0.0.1:25 and net/smtp pinned the TLS ServerName to the dial host, but the
relay's cert is for mail.<host>. Reimplement smtpSend (mirrors net/smtp.SendMail)
with an overridable IMAPConfig.SMTPServerName; default it to the mail host
(AGENTBBS_MAIL_SMTP_SERVERNAME). Now we dial the loopback for relay permission
yet verify the real hostname cert — no /etc/hosts hack. setup.sh upserts the new
var. Tested against a fake SMTP server (full MAIL/RCPT/DATA flow).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-23 15:54:30 +00:00

115 lines
2.7 KiB
Go

package mailbox
import (
"bufio"
"net"
"strings"
"sync"
"testing"
)
// fakeSMTP is a minimal SMTP server (no STARTTLS advertised) that records the
// envelope and body of one delivered message, so we can exercise smtpSend's
// dial→MAIL→RCPT→DATA→QUIT flow without real TLS.
type fakeSMTP struct {
addr string
ln net.Listener
mu sync.Mutex
from string
rcpts []string
body strings.Builder
gotMailFrom bool
}
func newFakeSMTP(t *testing.T) *fakeSMTP {
t.Helper()
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatal(err)
}
f := &fakeSMTP{addr: ln.Addr().String(), ln: ln}
go f.serve()
t.Cleanup(func() { _ = ln.Close() })
return f
}
func (f *fakeSMTP) serve() {
conn, err := f.ln.Accept()
if err != nil {
return
}
defer conn.Close()
br := bufio.NewReader(conn)
w := func(s string) { _, _ = conn.Write([]byte(s)) }
w("220 mock ESMTP\r\n")
inData := false
for {
line, err := br.ReadString('\n')
if err != nil {
return
}
if inData {
if strings.TrimRight(line, "\r\n") == "." {
inData = false
w("250 ok\r\n")
continue
}
f.mu.Lock()
f.body.WriteString(line)
f.mu.Unlock()
continue
}
up := strings.ToUpper(strings.TrimSpace(line))
switch {
case strings.HasPrefix(up, "EHLO"), strings.HasPrefix(up, "HELO"):
w("250 mock\r\n") // single line => no extensions (no STARTTLS)
case strings.HasPrefix(up, "MAIL FROM"):
f.mu.Lock()
f.from = strings.TrimSpace(line[len("MAIL FROM:"):])
f.gotMailFrom = true
f.mu.Unlock()
w("250 ok\r\n")
case strings.HasPrefix(up, "RCPT TO"):
f.mu.Lock()
f.rcpts = append(f.rcpts, strings.TrimSpace(line[len("RCPT TO:"):]))
f.mu.Unlock()
w("250 ok\r\n")
case strings.HasPrefix(up, "DATA"):
inData = true
w("354 go ahead\r\n")
case strings.HasPrefix(up, "QUIT"):
w("221 bye\r\n")
return
default:
w("250 ok\r\n")
}
}
}
func TestSMTPSendFlow(t *testing.T) {
srv := newFakeSMTP(t)
msg := []byte("Subject: hi\r\n\r\nbody text\r\n")
err := smtpSend(srv.addr, "", "", "", "alice@bbs.test", []string{"bob@example.com", "carol@example.com"}, msg)
if err != nil {
t.Fatalf("smtpSend: %v", err)
}
srv.mu.Lock()
defer srv.mu.Unlock()
if !srv.gotMailFrom || !strings.Contains(srv.from, "alice@bbs.test") {
t.Fatalf("MAIL FROM wrong: %q", srv.from)
}
if len(srv.rcpts) != 2 {
t.Fatalf("want 2 recipients, got %v", srv.rcpts)
}
if !strings.Contains(srv.body.String(), "body text") {
t.Fatalf("body not delivered: %q", srv.body.String())
}
}
func TestSMTPSendBadAddr(t *testing.T) {
if err := smtpSend("not-a-host-port", "", "", "", "a@b", []string{"c@d"}, []byte("x")); err == nil {
t.Fatal("expected error for malformed addr")
}
}