From 475dee9082f740f77a9e17d2e2242e647c860f13 Mon Sep 17 00:00:00 2001 From: Rick Arnold Date: Sun, 16 Dec 2012 20:19:35 -0500 Subject: [PATCH] net/smtp: add optional Hello method Add a Hello method that allows clients to set the server sent in the EHLO/HELO exchange; the default remains localhost. Based on CL 5555045 by rsc. Fixes #4219. R=golang-dev, rsc CC=golang-dev https://golang.org/cl/6946057 --- src/pkg/net/smtp/smtp.go | 65 ++++++++++-- src/pkg/net/smtp/smtp_test.go | 192 +++++++++++++++++++++++++++++++++- 2 files changed, 248 insertions(+), 9 deletions(-) diff --git a/src/pkg/net/smtp/smtp.go b/src/pkg/net/smtp/smtp.go index 59f6449f0a..4b91778770 100644 --- a/src/pkg/net/smtp/smtp.go +++ b/src/pkg/net/smtp/smtp.go @@ -13,6 +13,7 @@ package smtp import ( "crypto/tls" "encoding/base64" + "errors" "io" "net" "net/textproto" @@ -33,7 +34,10 @@ type Client struct { // map of supported extensions ext map[string]string // supported auth mechanisms - auth []string + auth []string + localName string // the name to use in HELO/EHLO + didHello bool // whether we've said HELO/EHLO + helloError error // the error from the hello } // Dial returns a new Client connected to an SMTP server at addr. @@ -55,12 +59,33 @@ func NewClient(conn net.Conn, host string) (*Client, error) { text.Close() return nil, err } - c := &Client{Text: text, conn: conn, serverName: host} - err = c.ehlo() - if err != nil { - err = c.helo() + c := &Client{Text: text, conn: conn, serverName: host, localName: "localhost"} + return c, nil +} + +// hello runs a hello exchange if needed. +func (c *Client) hello() error { + if !c.didHello { + c.didHello = true + err := c.ehlo() + if err != nil { + c.helloError = c.helo() + } + } + return c.helloError +} + +// Hello sends a HELO or EHLO to the server as the given host name. +// Calling this method is only necessary if the client needs control +// over the host name used. The client will introduce itself as "localhost" +// automatically otherwise. If Hello is called, it must be called before +// any of the other methods. +func (c *Client) Hello(localName string) error { + if c.didHello { + return errors.New("smtp: Hello called after other methods") } - return c, err + c.localName = localName + return c.hello() } // cmd is a convenience function that sends a command and returns the response @@ -79,14 +104,14 @@ func (c *Client) cmd(expectCode int, format string, args ...interface{}) (int, s // server does not support ehlo. func (c *Client) helo() error { c.ext = nil - _, _, err := c.cmd(250, "HELO localhost") + _, _, err := c.cmd(250, "HELO %s", c.localName) return err } // ehlo sends the EHLO (extended hello) greeting to the server. It // should be the preferred greeting for servers that support it. func (c *Client) ehlo() error { - _, msg, err := c.cmd(250, "EHLO localhost") + _, msg, err := c.cmd(250, "EHLO %s", c.localName) if err != nil { return err } @@ -113,6 +138,9 @@ func (c *Client) ehlo() error { // StartTLS sends the STARTTLS command and encrypts all further communication. // Only servers that advertise the STARTTLS extension support this function. func (c *Client) StartTLS(config *tls.Config) error { + if err := c.hello(); err != nil { + return err + } _, _, err := c.cmd(220, "STARTTLS") if err != nil { return err @@ -128,6 +156,9 @@ func (c *Client) StartTLS(config *tls.Config) error { // does not necessarily indicate an invalid address. Many servers // will not verify addresses for security reasons. func (c *Client) Verify(addr string) error { + if err := c.hello(); err != nil { + return err + } _, _, err := c.cmd(250, "VRFY %s", addr) return err } @@ -136,6 +167,9 @@ func (c *Client) Verify(addr string) error { // A failed authentication closes the connection. // Only servers that advertise the AUTH extension support this function. func (c *Client) Auth(a Auth) error { + if err := c.hello(); err != nil { + return err + } encoding := base64.StdEncoding mech, resp, err := a.Start(&ServerInfo{c.serverName, c.tls, c.auth}) if err != nil { @@ -178,6 +212,9 @@ func (c *Client) Auth(a Auth) error { // parameter. // This initiates a mail transaction and is followed by one or more Rcpt calls. func (c *Client) Mail(from string) error { + if err := c.hello(); err != nil { + return err + } cmdStr := "MAIL FROM:<%s>" if c.ext != nil { if _, ok := c.ext["8BITMIME"]; ok { @@ -227,6 +264,9 @@ func SendMail(addr string, a Auth, from string, to []string, msg []byte) error { if err != nil { return err } + if err := c.hello(); err != nil { + return err + } if ok, _ := c.Extension("STARTTLS"); ok { if err = c.StartTLS(nil); err != nil { return err @@ -267,6 +307,9 @@ func SendMail(addr string, a Auth, from string, to []string, msg []byte) error { // Extension also returns a string that contains any parameters the // server specifies for the extension. func (c *Client) Extension(ext string) (bool, string) { + if err := c.hello(); err != nil { + return false, "" + } if c.ext == nil { return false, "" } @@ -278,12 +321,18 @@ func (c *Client) Extension(ext string) (bool, string) { // Reset sends the RSET command to the server, aborting the current mail // transaction. func (c *Client) Reset() error { + if err := c.hello(); err != nil { + return err + } _, _, err := c.cmd(250, "RSET") return err } // Quit sends the QUIT command and closes the connection to the server. func (c *Client) Quit() error { + if err := c.hello(); err != nil { + return err + } _, _, err := c.cmd(221, "QUIT") if err != nil { return err diff --git a/src/pkg/net/smtp/smtp_test.go b/src/pkg/net/smtp/smtp_test.go index c315d185c9..2a11b26392 100644 --- a/src/pkg/net/smtp/smtp_test.go +++ b/src/pkg/net/smtp/smtp_test.go @@ -76,7 +76,7 @@ func TestBasic(t *testing.T) { bcmdbuf := bufio.NewWriter(&cmdbuf) var fake faker fake.ReadWriter = bufio.NewReadWriter(bufio.NewReader(strings.NewReader(basicServer)), bcmdbuf) - c := &Client{Text: textproto.NewConn(fake)} + c := &Client{Text: textproto.NewConn(fake), localName: "localhost"} if err := c.helo(); err != nil { t.Fatalf("HELO failed: %s", err) @@ -88,6 +88,7 @@ func TestBasic(t *testing.T) { t.Fatalf("Second EHLO failed: %s", err) } + c.didHello = true if ok, args := c.Extension("aUtH"); !ok || args != "LOGIN PLAIN" { t.Fatalf("Expected AUTH supported") } @@ -269,3 +270,192 @@ var newClient2Client = `EHLO localhost HELO localhost QUIT ` + +func TestHello(t *testing.T) { + + if len(helloServer) != len(helloClient) { + t.Fatalf("Hello server and client size mismatch") + } + + for i := 0; i < len(helloServer); i++ { + server := strings.Join(strings.Split(baseHelloServer+helloServer[i], "\n"), "\r\n") + client := strings.Join(strings.Split(baseHelloClient+helloClient[i], "\n"), "\r\n") + var cmdbuf bytes.Buffer + bcmdbuf := bufio.NewWriter(&cmdbuf) + var fake faker + fake.ReadWriter = bufio.NewReadWriter(bufio.NewReader(strings.NewReader(server)), bcmdbuf) + c, err := NewClient(fake, "fake.host") + if err != nil { + t.Fatalf("NewClient: %v", err) + } + c.localName = "customhost" + err = nil + + switch i { + case 0: + err = c.Hello("customhost") + case 1: + err = c.StartTLS(nil) + if err.Error() == "502 Not implemented" { + err = nil + } + case 2: + err = c.Verify("test@example.com") + case 3: + c.tls = true + c.serverName = "smtp.google.com" + err = c.Auth(PlainAuth("", "user", "pass", "smtp.google.com")) + case 4: + err = c.Mail("test@example.com") + case 5: + ok, _ := c.Extension("feature") + if ok { + t.Errorf("Expected FEATURE not to be supported") + } + case 6: + err = c.Reset() + case 7: + err = c.Quit() + case 8: + err = c.Verify("test@example.com") + if err != nil { + err = c.Hello("customhost") + if err != nil { + t.Errorf("Want error, got none") + } + } + default: + t.Fatalf("Unhandled command") + } + + if err != nil { + t.Errorf("Command %d failed: %v", i, err) + } + + bcmdbuf.Flush() + actualcmds := cmdbuf.String() + if client != actualcmds { + t.Errorf("Got:\n%s\nExpected:\n%s", actualcmds, client) + } + } +} + +var baseHelloServer = `220 hello world +502 EH? +250-mx.google.com at your service +250 FEATURE +` + +var helloServer = []string{ + "", + "502 Not implemented\n", + "250 User is valid\n", + "235 Accepted\n", + "250 Sender ok\n", + "", + "250 Reset ok\n", + "221 Goodbye\n", + "250 Sender ok\n", +} + +var baseHelloClient = `EHLO customhost +HELO customhost +` + +var helloClient = []string{ + "", + "STARTTLS\n", + "VRFY test@example.com\n", + "AUTH PLAIN AHVzZXIAcGFzcw==\n", + "MAIL FROM:\n", + "", + "RSET\n", + "QUIT\n", + "VRFY test@example.com\n", +} + +func TestSendMail(t *testing.T) { + server := strings.Join(strings.Split(sendMailServer, "\n"), "\r\n") + client := strings.Join(strings.Split(sendMailClient, "\n"), "\r\n") + var cmdbuf bytes.Buffer + bcmdbuf := bufio.NewWriter(&cmdbuf) + l, err := net.Listen("tcp", "127.0.0.1:0") + if err != nil { + t.Fatalf("Unable to to create listener: %v", err) + } + defer l.Close() + + go func(l net.Listener, data []string, w *bufio.Writer) { + i := 0 + conn, err := l.Accept() + if err != nil { + t.Log("Accept error: %v", err) + return + } + defer conn.Close() + + tc := textproto.NewConn(conn) + for i < len(data) && data[i] != "" { + tc.PrintfLine(data[i]) + for len(data[i]) >= 4 && data[i][3] == '-' { + i++ + tc.PrintfLine(data[i]) + } + read := false + for !read || data[i] == "354 Go ahead" { + msg, err := tc.ReadLine() + w.Write([]byte(msg + "\r\n")) + read = true + if err != nil { + t.Log("Read error: %v", err) + return + } + if data[i] == "354 Go ahead" && msg == "." { + break + } + } + i++ + } + }(l, strings.Split(server, "\r\n"), bcmdbuf) + + err = SendMail(l.Addr().String(), nil, "test@example.com", []string{"other@example.com"}, []byte(strings.Replace(`From: test@example.com +To: other@example.com +Subject: SendMail test + +SendMail is working for me. +`, "\n", "\r\n", -1))) + + if err != nil { + t.Errorf("%v", err) + } + + bcmdbuf.Flush() + actualcmds := cmdbuf.String() + if client != actualcmds { + t.Errorf("Got:\n%s\nExpected:\n%s", actualcmds, client) + } +} + +var sendMailServer = `220 hello world +502 EH? +250 mx.google.com at your service +250 Sender ok +250 Receiver ok +354 Go ahead +250 Data ok +221 Goodbye +` + +var sendMailClient = `EHLO localhost +HELO localhost +MAIL FROM: +RCPT TO: +DATA +From: test@example.com +To: other@example.com +Subject: SendMail test + +SendMail is working for me. +. +QUIT +` -- 2.48.1