don't return any forwarded hops if the header is invalid

src/lib.rs

@@ -74,6 +74,7 @@ pub fn real_ip(headers: &HeaderMap, remote: IpAddr, trusted_proxies: &[IpNet]) -
 
     'outer: for hop in hops.rev() {
         for proxy in trusted_proxies {
+            dbg!(proxy);
             if proxy.contains(&hop) {
                 continue 'outer;
             }
@@ -110,3 +111,25 @@ pub fn get_forwarded_for(headers: &HeaderMap) -> impl DoubleEndedIterator<Item =
 #[allow(dead_code)]
 #[doc = include_str!("../README.md")]
 fn test_readme_examples() {}
+
+#[test]
+fn test_malformed() {
+    use http::header::HeaderValue;
+    let mut headers = HeaderMap::new();
+    headers.insert(
+        "forwarded",
+        HeaderValue::from_static(
+            "by=203.0.111.42;for=1.2.3.4:8888,for=5.6.7.8;proto=https;nonsense",
+        ),
+    );
+    let trusted_proxies = [
+        IpAddr::from([2, 3, 4, 5]).into(),
+        IpAddr::from([5, 6, 7, 8]).into(),
+    ];
+    let remote = IpAddr::from([2, 3, 4, 5]);
+    assert!(get_forwarded_for(&headers).next().is_none());
+    assert_eq!(
+        Some(IpAddr::from([2, 3, 4, 5])),
+        real_ip(&headers, remote, &trusted_proxies)
+    );
+}