From 3f1b094cc92e17f1a74ba039130059300e64276c Mon Sep 17 00:00:00 2001
From: Denis Arh <denis.arh@gmail.com>
Date: Wed, 2 Sep 2020 13:09:41 +0200
Subject: [PATCH] Add SMTP_TSL_INSECURE and SMTP_TSL_SERVER_NAME for better
 SMTP TSL control

---
 corteza/corteza.go      | 24 +++++++++++++++++++++++-
 pkg/app/options/smtp.go |  8 +++++++-
 pkg/mail/mail.go        | 13 +++++++++++--
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/corteza/corteza.go b/corteza/corteza.go
index 60defc25e..5ea2a98f3 100644
--- a/corteza/corteza.go
+++ b/corteza/corteza.go
@@ -2,7 +2,9 @@ package corteza
 
 import (
 	"context"
+	"crypto/tls"
 	"github.com/cortezaproject/corteza-server/pkg/healthcheck"
+	gomail "gopkg.in/mail.v2"
 	"time"
 
 	"github.com/pkg/errors"
@@ -51,7 +53,27 @@ func (app *App) Setup(log *zap.Logger, opts *app.Options) (err error) {
 	defer sentry.Recover()
 
 	auth.SetupDefault(opts.Auth.Secret, int(opts.Auth.Expiry/time.Minute))
-	mail.SetupDialer(opts.SMTP.Host, opts.SMTP.Port, opts.SMTP.User, opts.SMTP.Pass, opts.SMTP.From)
+	mail.SetupDialer(
+		opts.SMTP.Host,
+		opts.SMTP.Port,
+		opts.SMTP.User,
+		opts.SMTP.Pass,
+		opts.SMTP.From,
+
+		// Apply TLS configuration
+		func(d *gomail.Dialer) {
+			if d.TLSConfig == nil {
+				d.TLSConfig = &tls.Config{ServerName: d.Host}
+			}
+
+			if opts.SMTP.TlsInsecure {
+				d.TLSConfig.InsecureSkipVerify = true
+			}
+
+			if opts.SMTP.TlsServerName != "" {
+				d.TLSConfig.ServerName = opts.SMTP.TlsServerName
+			}
+		})
 
 	http.SetupDefaults(
 		opts.HTTPClient.HttpClientTimeout,
diff --git a/pkg/app/options/smtp.go b/pkg/app/options/smtp.go
index 5db29bb53..6ab05921c 100644
--- a/pkg/app/options/smtp.go
+++ b/pkg/app/options/smtp.go
@@ -7,16 +7,22 @@ type (
 		User string `env:"SMTP_USER"`
 		Pass string `env:"SMTP_PASS"`
 		From string `env:"SMTP_FROM"`
+
+		TlsInsecure   bool   `env:"SMTP_TSL_INSECURE"`
+		TlsServerName string `env:"SMTP_TSL_SERVER_NAME"`
 	}
 )
 
 func SMTP(pfix string) (o *SMTPOpt) {
 	o = &SMTPOpt{
-		Host: "localhost:25",
+		Host: "localhost",
 		Port: 25,
 		User: "",
 		Pass: "",
 		From: "",
+
+		TlsInsecure:   false,
+		TlsServerName: "",
 	}
 
 	fill(o, pfix)
diff --git a/pkg/mail/mail.go b/pkg/mail/mail.go
index 910589433..015f40701 100644
--- a/pkg/mail/mail.go
+++ b/pkg/mail/mail.go
@@ -13,6 +13,8 @@ type (
 	Dialer interface {
 		DialAndSend(...*gomail.Message) error
 	}
+
+	applyCfg func(*gomail.Dialer)
 )
 
 const (
@@ -33,7 +35,7 @@ func init() {
 // SetupDialer setups SMTP dialer
 //
 // Host variable can contain "<host>:<port>" that will override port value
-func SetupDialer(host string, port int, user, pass, from string) {
+func SetupDialer(host string, port int, user, pass, from string, ff ...applyCfg) {
 	if host == "" {
 		defaultDialerError = errors.New("No hostname provided for SMTP")
 		return
@@ -59,12 +61,19 @@ func SetupDialer(host string, port int, user, pass, from string) {
 	}
 
 	defaultFrom = from
-	defaultDialer = gomail.NewDialer(
+	dialer := gomail.NewDialer(
 		host,
 		port,
 		user,
 		pass,
 	)
+
+	dialer.SSL = true
+	for _, fn := range ff {
+		fn(dialer)
+	}
+
+	defaultDialer = dialer
 }
 
 func New() *gomail.Message {