PLT-5904 (Server): Config flag for SMTP Cert Check. (#5857)

config/config.json

@@ -132,7 +132,8 @@
         "PushNotificationContents": "generic",
         "EnableEmailBatching": false,
         "EmailBatchingBufferSize": 256,
-        "EmailBatchingInterval": 30
+        "EmailBatchingInterval": 30,
+        "SkipServerCertificateVerification": false
     },
     "RateLimitSettings": {
         "Enable": false,

model/config.go

@@ -252,6 +252,7 @@ type EmailSettings struct {
 	EnableEmailBatching               *bool
 	EmailBatchingBufferSize           *int
 	EmailBatchingInterval             *int
+	SkipServerCertificateVerification *bool
 }
 
 type RateLimitSettings struct {
@@ -680,6 +681,11 @@ func (o *Config) SetDefaults() {
 		*o.EmailSettings.EmailBatchingInterval = EMAIL_BATCHING_INTERVAL
 	}
 
+	if o.EmailSettings.SkipServerCertificateVerification == nil {
+		o.EmailSettings.SkipServerCertificateVerification = new(bool)
+		*o.EmailSettings.SkipServerCertificateVerification = false
+	}
+
 	if !IsSafeLink(o.SupportSettings.TermsOfServiceLink) {
 		o.SupportSettings.TermsOfServiceLink = nil
 	}

utils/mail.go

@@ -25,7 +25,7 @@ func connectToSMTPServer(config *model.Config) (net.Conn, *model.AppError) {
 
 	if config.EmailSettings.ConnectionSecurity == model.CONN_SECURITY_TLS {
 		tlsconfig := &tls.Config{
-			InsecureSkipVerify: true,
+			InsecureSkipVerify: *config.EmailSettings.SkipServerCertificateVerification,
 			ServerName:         config.EmailSettings.SMTPServer,
 		}
 
@@ -56,7 +56,7 @@ func newSMTPClient(conn net.Conn, config *model.Config) (*smtp.Client, *model.Ap
 		}
 	} else if config.EmailSettings.ConnectionSecurity == model.CONN_SECURITY_STARTTLS {
 		tlsconfig := &tls.Config{
-			InsecureSkipVerify: true,
+			InsecureSkipVerify: *config.EmailSettings.SkipServerCertificateVerification,
 			ServerName:         config.EmailSettings.SMTPServer,
 		}
 		c.StartTLS(tlsconfig)