Enforce authorized_keys from restrictions

tests/integration_smoke.rs

@@ -223,6 +223,14 @@ fn start_echo_server() -> u16 {
 }
 
 fn write_native_client_auth(dir: &tempfile::TempDir, config_path: &std::path::Path) {
+    write_native_client_auth_with_options(dir, config_path, "");
+}
+
+fn write_native_client_auth_with_options(
+    dir: &tempfile::TempDir,
+    config_path: &std::path::Path,
+    options: &str,
+) {
     let ssh_dir = dir.path().join(".ssh");
     fs::create_dir_all(&ssh_dir).unwrap();
     let signing = ed25519_dalek::SigningKey::from_bytes(&[42u8; 32]);
@@ -232,11 +240,13 @@ fn write_native_client_auth(dir: &tempfile::TempDir, config_path: &std::path::Pa
     private
         .write_openssh_file(&ssh_dir.join("id_ed25519"), ssh_key::LineEnding::LF)
         .unwrap();
-    fs::write(
-        dir.path().join("authorized_keys"),
-        format!("{}\n", private.public_key().to_openssh().unwrap()),
-    )
-    .unwrap();
+    let public = private.public_key().to_openssh().unwrap();
+    let line = if options.is_empty() {
+        public
+    } else {
+        format!("{options} {public}")
+    };
+    fs::write(dir.path().join("authorized_keys"), format!("{line}\n")).unwrap();
 
     let config = load_server_config(Some(config_path.to_path_buf())).unwrap();
     let host_signing = load_or_create_host_key(&config).unwrap();
@@ -556,6 +566,21 @@ fn native_attach_only_smoke() {
     assert!(stderr.contains("terminal_ready"), "stderr={stderr}");
 }
 
+#[test]
+fn native_attach_enforces_authorized_keys_from_option() {
+    let dir = tempfile::tempdir().unwrap();
+    let port = free_udp_port();
+    let config = write_server_config(&dir, port);
+    write_native_client_auth_with_options(&dir, &config, "from=\"10.99.0.0/16\"");
+    let mut server = start_server(&dir, &config);
+    let output = native_attach_once(&dir, port);
+    let _ = server.kill();
+    let _ = server.wait();
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(!output.status.success(), "stderr={stderr}");
+    assert!(stderr.contains("from="), "stderr={stderr}");
+}
+
 #[test]
 fn native_attach_only_smoke_uses_ssh_agent() {
     let dir = tempfile::tempdir().unwrap();