Files
sxchnge/backend/notifications/email/smtp_test.go

224 lines
7.7 KiB
Go

package email
import (
"context"
"crypto/tls"
"crypto/x509"
"encoding/base64"
"fmt"
"io"
"mime"
"mime/multipart"
"net"
"net/http/httptest"
"net/mail"
"net/textproto"
"strconv"
"strings"
"sync/atomic"
"testing"
"time"
"git.sendico.io/tech/sxchnge/notifications/model"
)
type smtpFixture struct {
settings smtpSettings
root *x509.CertPool
body chan []byte
auth atomic.Bool
}
func smtpServer(t *testing.T, reject string, code int) *smtpFixture {
t.Helper()
certServer := httptest.NewTLSServer(nil)
cert := certServer.TLS.Certificates[0]
root := x509.NewCertPool()
root.AddCert(certServer.Certificate())
certServer.Close()
listener, err := tls.Listen("tcp", "127.0.0.1:0", &tls.Config{Certificates: []tls.Certificate{cert}, MinVersion: tls.VersionTLS12})
if err != nil {
t.Fatal(err)
}
t.Cleanup(func() { _ = listener.Close() })
host, port, _ := net.SplitHostPort(listener.Addr().String())
n, _ := strconv.Atoi(port)
f := &smtpFixture{settings: smtpSettings{Host: host, Port: n, Username: "sender@example.com", SenderAddress: "sender@example.com", SenderName: "SXCHNGE", NetworkTimeout: 2}, root: root, body: make(chan []byte, 1)}
go func() {
conn, err := listener.Accept()
if err != nil {
return
}
defer conn.Close()
_ = conn.SetDeadline(time.Now().Add(5 * time.Second))
if reject == "greeting" {
_ = conn.(*tls.Conn).Handshake()
_, _ = io.Copy(io.Discard, conn)
return
}
c := textproto.NewConn(conn)
if c.PrintfLine("220 localhost ESMTP") != nil {
return
}
for {
line, err := c.ReadLine()
if err != nil {
return
}
command := strings.SplitN(line, " ", 2)[0]
if command == reject {
_ = c.PrintfLine("%d rejected recipient user@example.com credential test-password", code)
continue
}
switch command {
case "EHLO":
_ = c.PrintfLine("250-localhost\r\n250 AUTH PLAIN")
case "AUTH":
want := "AUTH PLAIN " + base64.StdEncoding.EncodeToString([]byte("\x00sender@example.com\x00test-password"))
f.auth.Store(line == want)
_ = c.PrintfLine("235 authenticated")
case "MAIL", "RCPT":
_ = c.PrintfLine("250 OK")
case "DATA":
_ = c.PrintfLine("354 send message")
body, err := c.ReadDotBytes()
if err != nil {
return
}
f.body <- body
if reject == "final" {
_ = c.PrintfLine("%d final rejection", code)
} else if reject == "disconnect" {
return
} else {
_ = c.PrintfLine("250 queued")
}
case "QUIT":
// A lost QUIT reply must not turn accepted DATA into UNKNOWN.
return
default:
_ = c.PrintfLine("500 unexpected command")
}
}
}()
return f
}
func (f *smtpFixture) sender() *smtpSender {
return &smtpSender{settings: f.settings, password: "test-password", tls: &tls.Config{ServerName: f.settings.Host, RootCAs: f.root, MinVersion: tls.VersionTLS12}}
}
func TestSMTPAcceptanceAndMIME(t *testing.T) {
f := smtpServer(t, "", 0)
sender := f.sender()
email := model.Email{Address: "user@example.com", Subject: "Подтвердите почту", Text: "Confirm code 123456\n.line", HTML: "<p>Confirm code 123456</p>"}
out := sender.Send(context.Background(), "notification-id", email)
if out.State != model.Accepted || out.SMTPStatus != 250 || !f.auth.Load() {
t.Fatal("SMTP acceptance/authentication failed", out)
}
msg, err := mail.ReadMessage(strings.NewReader(string(<-f.body)))
if err != nil {
t.Fatal(err)
}
subject, err := new(mime.WordDecoder).DecodeHeader(msg.Header.Get("Subject"))
if err != nil || subject != email.Subject {
t.Fatal("wrong MIME subject", subject, err)
}
if msg.Header.Get("From") != "\"SXCHNGE\" <sender@example.com>" || !strings.HasSuffix(msg.Header.Get("Message-ID"), "@example.com>") {
t.Fatal("invalid sender/message identifier")
}
kind, params, err := mime.ParseMediaType(msg.Header.Get("Content-Type"))
if err != nil || kind != "multipart/alternative" {
t.Fatal("wrong MIME type", kind, err)
}
parts := multipart.NewReader(msg.Body, params["boundary"])
for _, want := range []string{email.Text, email.HTML} {
part, err := parts.NextPart()
if err != nil {
t.Fatal(err)
}
body, err := io.ReadAll(part)
if err != nil || strings.ReplaceAll(string(body), "\r\n", "\n") != want {
t.Fatal("incorrect MIME content", err)
}
}
}
func TestSMTPFailureSafety(t *testing.T) {
for _, tc := range []struct {
stage string
code int
state model.State
failure string
}{
{"AUTH", 535, model.Failed, "provider_authentication_failed"},
{"RCPT", 550, model.Failed, "provider_rejected"},
{"final", 451, model.RetryWait, "provider_temporarily_unavailable"},
{"disconnect", 0, model.Unknown, "provider_outcome_unknown"},
} {
t.Run(fmt.Sprintf("%s-%d", tc.stage, tc.code), func(t *testing.T) {
f := smtpServer(t, tc.stage, tc.code)
out := f.sender().Send(context.Background(), "id", model.Email{Address: "user@example.com", Subject: "Subject", Text: "Body"})
if out.State != tc.state || out.Code != tc.failure || out.SMTPStatus != tc.code {
t.Fatal("incorrect SMTP classification", out)
}
if strings.Contains(out.ProviderMessage, "test-password") || strings.Contains(out.ProviderMessage, "user@example.com") {
t.Fatal("SMTP rejection leaked private data")
}
if tc.code == 451 && out.RetryAfter <= 0 {
t.Fatal("temporary rejection did not schedule retry")
}
})
}
}
func TestSMTPCertificateAndCancellation(t *testing.T) {
t.Run("untrusted certificate", func(t *testing.T) {
f := smtpServer(t, "", 0)
sender := f.sender()
sender.tls.RootCAs = x509.NewCertPool()
if out := sender.Send(context.Background(), "id", model.Email{Address: "user@example.com", Text: "Body"}); out.State != model.Unknown || f.auth.Load() {
t.Fatal("untrusted TLS accepted", out)
}
})
t.Run("cancel blocked greeting", func(t *testing.T) {
f := smtpServer(t, "greeting", 0)
ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
defer cancel()
started := time.Now()
if out := f.sender().Send(ctx, "id", model.Email{Address: "user@example.com", Text: "Body"}); out.State != model.Unknown || time.Since(started) > time.Second {
t.Fatal("SMTP ignored cancellation", out)
}
})
}
func TestSMTPConfigAndHeaderValidation(t *testing.T) {
t.Setenv("TEST_SMTP_PASSWORD", "test-password")
valid := map[string]any{"host": "mail.example.com", "port": 465, "username": "sender@example.com", "password_env": "TEST_SMTP_PASSWORD", "sender_address": "sender@example.com", "network_timeout": 10}
if _, err := New(Config{Driver: SMTP, Settings: valid}); err != nil {
t.Fatal(err)
}
for field, value := range map[string]any{"port": 0, "host": "https://bad", "username": "bad", "network_timeout": 0, "password_env": "MISSING_SMTP_PASSWORD", "typo": true} {
settings := map[string]any{}
for key, item := range valid {
settings[key] = item
}
settings[field] = value
if _, err := New(Config{Driver: SMTP, Settings: settings}); err == nil {
t.Fatalf("invalid setting %s accepted", field)
}
}
if _, err := smtpMessage(smtpSettings{}, "id", model.Email{Address: "user@example.com", Subject: "Subject\r\nBcc: stolen@example.com", Text: "Body"}); err == nil {
t.Fatal("header injection accepted")
}
}
func TestSMTPAuthenticationDiagnosticRedactsEncodedCredential(t *testing.T) {
f := &smtpSender{settings: smtpSettings{Username: "sender@example.com"}, password: "a"}
auth := base64.StdEncoding.EncodeToString([]byte("\x00sender@example.com\x00a"))
out := f.failure(&textproto.Error{Code: 535, Msg: "Rejected AUTH " + auth}, "id", model.Email{})
if out.SMTPStatus != 535 || strings.Contains(out.ProviderMessage, auth) || !strings.Contains(out.ProviderMessage, "AUTH [redacted]") {
t.Fatalf("encoded SMTP credential was not fully redacted: %q", out.ProviderMessage)
}
}