Convert email domains to punycode

src/mail.rs

@@ -259,6 +259,18 @@ pub fn send_change_email(address: &str, token: &str) -> EmptyResult {
 }
 
 fn send_email(address: &str, subject: &str, body_html: &str, body_text: &str) -> EmptyResult {
+    let address_split: Vec<&str> = address.rsplitn(2, '@').collect();
+    if address_split.len() != 2 {
+        err!("Invalid email address (no @)");
+    }
+
+    let domain_puny = match idna::domain_to_ascii_strict(address_split[1]) {
+        Ok(d) => d,
+        Err(_) => err!("Can't convert email domain to ASCII representation"),
+    };
+
+    let address = format!("{}@{}", address_split[0], domain_puny);
+
     let html = PartBuilder::new()
         .body(encode_to_str(body_html))
         .header(("Content-Type", "text/html; charset=utf-8"))