From 032ca175e4d671a57cdad03c3fbab5f63dea8183 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Wed, 7 Jul 2021 07:12:15 -0400
Subject: [PATCH] add support for email timeouts

---
 default.yaml       |  1 +
 irc/email/email.go |  4 +++-
 irc/smtp/smtp.go   | 29 ++++++++++++++++++++++++-----
 traditional.yaml   |  1 +
 4 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/default.yaml b/default.yaml
index 289165d2..d9055828 100644
--- a/default.yaml
+++ b/default.yaml
@@ -413,6 +413,7 @@ accounts:
             #     password: "hunter2"
             blacklist-regexes:
             #    - ".*@mailinator.com"
+            timeout: 60s
 
     # throttle account login attempts (to prevent either password guessing, or DoS
     # attacks on the server aimed at forcing repeated expensive bcrypt computations)
diff --git a/irc/email/email.go b/irc/email/email.go
index 11139fd9..d06f25e0 100644
--- a/irc/email/email.go
+++ b/irc/email/email.go
@@ -9,6 +9,7 @@ import (
 	"net"
 	"regexp"
 	"strings"
+	"time"
 
 	"github.com/ergochat/ergo/irc/smtp"
 )
@@ -40,6 +41,7 @@ type MailtoConfig struct {
 	MTAReal              MTAConfig `yaml:"mta"`
 	BlacklistRegexes     []string  `yaml:"blacklist-regexes"`
 	blacklistRegexes     []*regexp.Regexp
+	Timeout              time.Duration
 }
 
 func (config *MailtoConfig) Postprocess(heloDomain string) (err error) {
@@ -126,5 +128,5 @@ func SendMail(config MailtoConfig, recipient string, msg []byte) (err error) {
 		addr = fmt.Sprintf("%s:smtp", mx)
 	}
 
-	return smtp.SendMail(addr, auth, config.HeloDomain, config.Sender, []string{recipient}, msg, config.RequireTLS)
+	return smtp.SendMail(addr, auth, config.HeloDomain, config.Sender, []string{recipient}, msg, config.RequireTLS, config.Timeout)
 }
diff --git a/irc/smtp/smtp.go b/irc/smtp/smtp.go
index 80b76992..d17b09ae 100644
--- a/irc/smtp/smtp.go
+++ b/irc/smtp/smtp.go
@@ -24,6 +24,11 @@ import (
 	"net"
 	"net/textproto"
 	"strings"
+	"time"
+)
+
+var (
+	ErrTimedOut = errors.New("Timed out")
 )
 
 // A Client represents a client connection to an SMTP server.
@@ -48,11 +53,25 @@ type Client struct {
 
 // Dial returns a new Client connected to an SMTP server at addr.
 // The addr must include a port, as in "mail.example.com:smtp".
-func Dial(addr string) (*Client, error) {
-	conn, err := net.Dial("tcp", addr)
+func Dial(addr string, timeout time.Duration) (*Client, error) {
+	var conn net.Conn
+	var err error
+	start := time.Now()
+	if timeout == 0 {
+		conn, err = net.Dial("tcp", addr)
+	} else {
+		conn, err = net.DialTimeout("tcp", addr, timeout)
+	}
 	if err != nil {
 		return nil, err
 	}
+	if timeout != 0 {
+		remaining := timeout - time.Since(start)
+		if remaining <= 0 {
+			return nil, ErrTimedOut
+		}
+		conn.SetDeadline(time.Now().Add(remaining))
+	}
 	host, _, _ := net.SplitHostPort(addr)
 	return NewClient(conn, host)
 }
@@ -316,8 +335,8 @@ var testHookStartTLS func(*tls.Config) // nil, except for tests
 // attachments (see the mime/multipart package), or other mail
 // functionality. Higher-level packages exist outside of the standard
 // library.
-// XXX: modified in Oragono to add `requireTLS` and `heloDomain` arguments
-func SendMail(addr string, a Auth, heloDomain string, from string, to []string, msg []byte, requireTLS bool) error {
+// XXX: modified in Ergo to add `requireTLS`, `heloDomain`, and `timeout` arguments
+func SendMail(addr string, a Auth, heloDomain string, from string, to []string, msg []byte, requireTLS bool, timeout time.Duration) error {
 	if err := validateLine(from); err != nil {
 		return err
 	}
@@ -326,7 +345,7 @@ func SendMail(addr string, a Auth, heloDomain string, from string, to []string,
 			return err
 		}
 	}
-	c, err := Dial(addr)
+	c, err := Dial(addr, timeout)
 	if err != nil {
 		return err
 	}
diff --git a/traditional.yaml b/traditional.yaml
index 5d431c60..bee90c4d 100644
--- a/traditional.yaml
+++ b/traditional.yaml
@@ -386,6 +386,7 @@ accounts:
             #     password: "hunter2"
             blacklist-regexes:
             #    - ".*@mailinator.com"
+            timeout: 60s
 
     # throttle account login attempts (to prevent either password guessing, or DoS
     # attacks on the server aimed at forcing repeated expensive bcrypt computations)