Mirrors/smtpd
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Different fixes.

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Handle empty e-mail addresses.
Implemented MaxRecipients check.
Announce PIPELINING support.
Corrected error code on Too Busy error.
Implemented DataTimeout for timeouts on DATA.
Use textproto.DotReader in handleDATA to implement dot-stuffing.
Reset deadlines on old socket in STARTTLS, add new deadlines to new TLS socket.
This commit is contained in:
Christian Joergensen 2014-07-17 16:00:44 +02:00
parent 3b49f5e70d
commit a0c514f12d
5 changed files with 226 additions and 39 deletions
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8
address.go
View File

@ -6,8 +6,14 @@ import (
)
func parseAddress(src string) (string, error) {
if src[0] != '<' || src[len(src)-1] != '>' || strings.Count(src, "@") != 1 {
if src[0] != '<' || src[len(src)-1] != '>' {
return "", fmt.Errorf("Ill-formatted e-mail address: %s", src)
}
if strings.Count(src, "@") > 1 {
return "", fmt.Errorf("Ill-formatted e-mail address: %s", src)
}
return src[1 : len(src)-1], nil
}

2
example_test.go
View File

@ -27,6 +27,7 @@ func ExampleServer() {
},
Handler: func(peer smtpd.Peer, env smtpd.Envelope) error {
return smtp.SendMail(
"smtp.gmail.com:587",
smtp.PlainAuth(
@ -39,6 +40,7 @@ func ExampleServer() {
env.Recipients,
env.Data,
)
},
}

79
protocol.go
View File

@ -6,7 +6,11 @@ import (
"crypto/tls"
"encoding/base64"
"fmt"
"io"
"io/ioutil"
"net/textproto"
"strings"
"time"
)
type command struct {
@ -178,6 +182,11 @@ func (session *session) handleRCPT(cmd command) {
return
}
if len(session.envelope.Recipients) >= session.server.MaxRecipients {
session.reply(550, "Too many recipients")
return
}
addr, err := parseAddress(cmd.params[1])
if err != nil {
@ -219,12 +228,23 @@ func (session *session) handleSTARTTLS(cmd command) {
return
}
// Reset HeloName as a new EHLO/HELO is required after STARTTLS
session.peer.HeloName = ""
// Reset deadlines on the underlying connection before I replace it
// with a TLS connection
session.conn.SetDeadline(time.Time{})
// Replace connection with a TLS connection
session.conn = tlsConn
session.reader = bufio.NewReader(tlsConn)
session.writer = bufio.NewWriter(tlsConn)
session.scanner = bufio.NewScanner(session.reader)
session.tls = true
// Flush the connection to set new timeout deadlines
session.flush()
return
}
@ -237,46 +257,47 @@ func (session *session) handleDATA(cmd command) {
}
session.reply(354, "Go ahead. End your data with <CR><LF>.<CR><LF>")
session.conn.SetDeadline(time.Now().Add(session.server.DataTimeout))
data := &bytes.Buffer{}
done := false
reader := textproto.NewReader(session.reader).DotReader()
for session.scanner.Scan() {
_, err := io.CopyN(data, reader, int64(session.server.MaxMessageSize))
line := session.scanner.Text()
if err == io.EOF {
if line == "." {
done = true
break
// EOF was reached before MaxMessageSize
// Accept and deliver message
session.envelope.Data = data.Bytes()
if err := session.deliver(); err != nil {
session.error(err)
} else {
session.reply(250, "Thank you.")
}
data.Write([]byte(line))
data.Write([]byte("\r\n"))
}
if !done {
return
}
if data.Len() > session.server.MaxMessageSize {
session.reply(550, fmt.Sprintf(
"Message exceeded max message size of %d bytes",
session.server.MaxMessageSize,
))
return
}
session.envelope.Data = data.Bytes()
err := session.deliver()
if err != nil {
session.error(err)
} else {
session.reply(250, "Thank you.")
// Network error, ignore
return
}
// Discard the rest and report an error.
_, err = io.Copy(ioutil.Discard, reader)
if err != nil {
// Network error, ignore
return
}
session.reply(552, fmt.Sprintf(
"Message exceeded max message size of %d bytes",
session.server.MaxMessageSize,
))
return
}
func (session *session) handleRSET(cmd command) {
@ -298,7 +319,7 @@ func (session *session) handleQUIT(cmd command) {
func (session *session) handleAUTH(cmd command) {
if session.server.Authenticator == nil {
if session.server.Authenticator == nil {
session.reply(502, "AUTH not supported.")
return
}

21
smtpd.go
View File

@ -18,9 +18,11 @@ type Server struct {
ReadTimeout time.Duration // Socket timeout for read operations. (default: 60s)
WriteTimeout time.Duration // Socket timeout for write operations. (default: 60s)
DataTimeout time.Duration // Socket timeout for DATA command (default: 5m)
MaxMessageSize int // Max message size in bytes. (default: 10240000)
MaxConnections int // Max concurrent connections, use -1 to disable. (default: 100)
MaxMessageSize int // Max message size in bytes. (default: 10240000)
MaxRecipients int // Max RCPT TO calls for each envelope. (default: 100)
// New e-mails are handed off to this function.
// Can be left empty for a NOOP server.
@ -168,6 +170,10 @@ func (srv *Server) configureDefaults() {
srv.MaxConnections = 100
}
if srv.MaxRecipients == 0 {
srv.MaxRecipients = 100
}
if srv.ReadTimeout == 0 {
srv.ReadTimeout = time.Second * 60
}
@ -176,6 +182,10 @@ func (srv *Server) configureDefaults() {
srv.WriteTimeout = time.Second * 60
}
if srv.DataTimeout == 0 {
srv.DataTimeout = time.Minute * 5
}
if srv.ForceTLS && srv.TLSConfig == nil {
log.Fatal("Cannot use ForceTLS with no TLSConfig")
}
@ -211,7 +221,7 @@ func (session *session) serve() {
}
func (session *session) reject() {
session.reply(450, "Too busy. Try again later.")
session.reply(421, "Too busy. Try again later.")
session.close()
}
@ -231,14 +241,14 @@ func (session *session) welcome() {
}
func (session *session) reply(code int, message string) {
fmt.Fprintf(session.writer, "%d %s\r\n", code, message)
session.flush()
}
func (session *session) flush() {
session.conn.SetWriteDeadline(time.Now().Add(session.server.WriteTimeout))
session.writer.Flush()
session.conn.SetReadDeadline(time.Now().Add(session.server.ReadTimeout))
}
func (session *session) error(err error) {
@ -254,6 +264,7 @@ func (session *session) extensions() []string {
extensions := []string{
fmt.Sprintf("SIZE %d", session.server.MaxMessageSize),
"8BITMIME",
"PIPELINING",
}
if session.server.TLSConfig != nil && !session.tls {

155
smtpd_test.go
View File

@ -533,8 +533,8 @@ func TestHandler(t *testing.T) {
if env.Recipients[0] != "recipient@example.net" {
t.Fatalf("Unknown recipient: %v", env.Recipients[0])
}
if string(env.Data) != "This is the email body\r\n" {
t.Fatalf("Wrong message body: %v", env.Data)
if string(env.Data) != "This is the email body\n" {
t.Fatalf("Wrong message body: %v", string(env.Data))
}
return nil
},
@ -686,6 +686,46 @@ func TestNoMaxConnections(t *testing.T) {
c1.Close()
}
func TestMaxRecipients(t *testing.T) {
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatalf("Listen failed: %v", err)
}
defer ln.Close()
server := &smtpd.Server{
MaxRecipients: 1,
}
go func() {
server.Serve(ln)
}()
c, err := smtp.Dial(ln.Addr().String())
if err != nil {
t.Fatalf("Dial failed: %v", err)
}
if err := c.Mail("sender@example.org"); err != nil {
t.Fatalf("MAIL failed: %v", err)
}
if err := c.Rcpt("recipient@example.net"); err != nil {
t.Fatalf("RCPT failed: %v", err)
}
if err := c.Rcpt("recipient@example.net"); err == nil {
t.Fatal("RCPT succeeded despite MaxRecipients = 1")
}
if err := c.Quit(); err != nil {
t.Fatalf("QUIT failed: %v", err)
}
}
func TestInvalidHelo(t *testing.T) {
ln, err := net.Listen("tcp", "127.0.0.1:0")
@ -732,7 +772,7 @@ func TestInvalidSender(t *testing.T) {
t.Fatalf("Dial failed: %v", err)
}
if err := c.Mail("invalid"); err == nil {
if err := c.Mail("invalid@@example.org"); err == nil {
t.Fatal("Unexpected MAIL success")
}
@ -762,7 +802,7 @@ func TestInvalidRecipient(t *testing.T) {
t.Fatalf("Mail failed: %v", err)
}
if err := c.Rcpt("invalid"); err == nil {
if err := c.Rcpt("invalid@@example.org"); err == nil {
t.Fatal("Unexpected RCPT success")
}
@ -878,3 +918,110 @@ func TestInterruptedDATA(t *testing.T) {
c.Close()
}
func TestTimeoutClose(t *testing.T) {
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatalf("Listen failed: %v", err)
}
defer ln.Close()
server := &smtpd.Server{
MaxConnections: 1,
ReadTimeout: time.Second,
WriteTimeout: time.Second,
}
go func() {
server.Serve(ln)
}()
c1, err := smtp.Dial(ln.Addr().String())
if err != nil {
t.Fatalf("Dial failed: %v", err)
}
time.Sleep(time.Second * 2)
c2, err := smtp.Dial(ln.Addr().String())
if err != nil {
t.Fatalf("Dial failed: %v", err)
}
if err := c1.Mail("sender@example.org"); err == nil {
t.Fatal("MAIL succeeded despite being timed out.")
}
if err := c2.Mail("sender@example.org"); err != nil {
t.Fatalf("MAIL failed: %v", err)
}
if err := c2.Quit(); err != nil {
t.Fatalf("Quit failed: %v", err)
}
c2.Close()
}
func TestTLSTimeout(t *testing.T) {
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatalf("Listen failed: %v", err)
}
defer ln.Close()
cert, err := tls.X509KeyPair(localhostCert, localhostKey)
if err != nil {
t.Fatalf("Cert load failed: %v", err)
}
server := &smtpd.Server{
TLSConfig: &tls.Config{
Certificates: []tls.Certificate{cert},
},
ReadTimeout: time.Second * 2,
WriteTimeout: time.Second * 2,
}
go func() {
server.Serve(ln)
}()
c, err := smtp.Dial(ln.Addr().String())
if err != nil {
t.Fatalf("Dial failed: %v", err)
}
if err := c.StartTLS(&tls.Config{InsecureSkipVerify: true}); err != nil {
t.Fatalf("STARTTLS failed: %v", err)
}
time.Sleep(time.Second)
if err := c.Mail("sender@example.org"); err != nil {
t.Fatalf("MAIL failed: %v", err)
}
time.Sleep(time.Second)
if err := c.Rcpt("recipient@example.net"); err != nil {
t.Fatalf("RCPT failed: %v", err)
}
time.Sleep(time.Second)
if err := c.Rcpt("recipient@example.net"); err != nil {
t.Fatalf("RCPT failed: %v", err)
}
time.Sleep(time.Second)
if err := c.Quit(); err != nil {
t.Fatalf("Quit failed: %v", err)
}
}