net/smtp: return error from SendMail when required AUTH not available

Return an error if an Auth is passed to SendMail but the server does not support authentication.

Fixes #22145

Change-Id: I49a37259c47bbe5145e30fa8a2d05444e60cb378
Reviewed-on: https://go-review.googlesource.com/79776
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/net/smtp/smtp.go b/src/net/smtp/smtp.go
index cf699e6be82f98526a339be75866f08ea8e2c754..e4e12ae5ee92821633851d09867ec96239eb74d5 100644 (file)
--- a/src/net/smtp/smtp.go
+++ b/src/net/smtp/smtp.go
@@ -343,10 +343,11 @@ func SendMail(addr string, a Auth, from string, to []string, msg []byte) error {
                }
        }
        if a != nil && c.ext != nil {
-               if _, ok := c.ext["AUTH"]; ok {
-                       if err = c.Auth(a); err != nil {
-                               return err
-                       }
+               if _, ok := c.ext["AUTH"]; !ok {
+                       return errors.New("smtp: server doesn't support AUTH")
+               }
+               if err = c.Auth(a); err != nil {
+                       return err
                }
        }
        if err = c.Mail(from); err != nil {

diff --git a/src/net/smtp/smtp_test.go b/src/net/smtp/smtp_test.go
index d489922597e5933cf8bfb836d3c7b0e3b376bb7e..e97aaa44863ee381055d4e8487653610eb740c85 100644 (file)
--- a/src/net/smtp/smtp_test.go
+++ b/src/net/smtp/smtp_test.go
@@ -15,6 +15,7 @@ import (
        "net/textproto"
        "runtime"
        "strings"
+       "sync"
        "testing"
        "time"
 )
@@ -635,6 +636,50 @@ SendMail is working for me.
 QUIT
 `
 
+func TestSendMailWithAuth(t *testing.T) {
+       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()
+       wg := sync.WaitGroup{}
+       var done = make(chan struct{})
+       go func() {
+               defer wg.Done()
+               conn, err := l.Accept()
+               if err != nil {
+                       t.Errorf("Accept error: %v", err)
+                       return
+               }
+               defer conn.Close()
+
+               tc := textproto.NewConn(conn)
+               tc.PrintfLine("220 hello world")
+               msg, err := tc.ReadLine()
+               if msg == "EHLO localhost" {
+                       tc.PrintfLine("250 mx.google.com at your service")
+               }
+               // for this test case, there should have no more traffic
+               <-done
+       }()
+       wg.Add(1)
+
+       err = SendMail(l.Addr().String(), PlainAuth("", "user", "pass", "smtp.google.com"), "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.Error("SendMail: Server doesn't support AUTH, expected to get an error, but got none ")
+       }
+       if err.Error() != "smtp: server doesn't support AUTH" {
+               t.Errorf("Expected: smtp: server doesn't support AUTH, got: %s", err)
+       }
+       close(done)
+       wg.Wait()
+}
+
 func TestAuthFailed(t *testing.T) {
        server := strings.Join(strings.Split(authFailedServer, "\n"), "\r\n")
        client := strings.Join(strings.Split(authFailedClient, "\n"), "\r\n")
@@ -830,14 +875,9 @@ func init() {
 }
 
 func sendMail(hostPort string) error {
-       host, _, err := net.SplitHostPort(hostPort)
-       if err != nil {
-               return err
-       }
-       auth := PlainAuth("", "", "", host)
        from := "joe1@example.com"
        to := []string{"joe2@example.com"}
-       return SendMail(hostPort, auth, from, to, []byte("Subject: test\n\nhowdy!"))
+       return SendMail(hostPort, nil, from, to, []byte("Subject: test\n\nhowdy!"))
 }
 
 // (copied from net/http/httptest)