fix(site-import): BLOCKED_NETS 补 v6 未指定/组播/保留段与 NAT64

- ::/128（v6 版 0.0.0.0，此前两层防线均放行）+ 224.0.0.0/4（组播）
  + 240.0.0.0/4（保留/广播，含 255.255.255.255）+ 64:ff9b::/96（NAT64）
  + 198.18.0.0/15（基准段）
- 测试 +9：六段参数化钉位、http://[::]/x URL 层拒绝、重定向协议切换
  （302→ftp://）第二跳拦截、DNS rebinding 端到端（真实 client 仅打桩
  getaddrinfo 返 10.x，证明连接层校验先于连接发生）

Co-Authored-By: Claude Code <noreply@anthropic.com>

app/platform/site_import/safe_fetch.py

@@ -28,8 +28,10 @@ from httpcore._exceptions import ConnectError, ConnectTimeout, map_exceptions
 
 BLOCKED_NETS = [ipaddress.ip_network(n) for n in [
     "127.0.0.0/8", "10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16",
-    "169.254.0.0/16", "0.0.0.0/8", "100.64.0.0/10", "::1/128",
-    "fc00::/7", "fe80::/10", "::ffff:0:0/96",
+    "169.254.0.0/16", "0.0.0.0/8", "100.64.0.0/10",
+    "224.0.0.0/4", "240.0.0.0/4", "198.18.0.0/15",
+    "::1/128", "fc00::/7", "fe80::/10", "::ffff:0:0/96",
+    "::/128", "64:ff9b::/96",
 ]]
 ALLOWED_PORTS = {80, 443}
 MAX_REDIRECTS = 5

tests/test_safe_fetch.py

@@ -77,6 +77,14 @@ class TestIsBlockedIp:
     def test_私网段全拒(self, ip):
         assert safe_fetch.is_blocked_ip(ip) is True
 
+    @pytest.mark.parametrize("ip", [
+        "::", "224.0.0.1", "240.0.0.1", "255.255.255.255",
+        "64:ff9b::1.2.3.4", "198.18.0.1",
+    ])
+    def test_补充禁段全拒(self, ip):
+        """v6 未指定/组播/保留广播/NAT64/基准段——补丁钉位（::/128 是 v6 版 0.0.0.0）。"""
+        assert safe_fetch.is_blocked_ip(ip) is True
+
     @pytest.mark.parametrize("ip", ["8.8.8.8", "1.1.1.1", "47.254.176.10", "2606:4700::1"])
     def test_公网放行(self, ip):
         assert safe_fetch.is_blocked_ip(ip) is False
@@ -117,6 +125,11 @@ class TestFetch:
         with pytest.raises(safe_fetch.FetchError):
             await safe_fetch.fetch("file:///etc/passwd")
 
+    async def test_ipv6未指定地址URL拒绝(self):
+        """http://[::]/ —— v6 版 0.0.0.0，URL 层必须拒（urlsplit 剥括号得 "::"）。"""
+        with pytest.raises(safe_fetch.FetchError):
+            await safe_fetch.fetch("http://[::]/x")
+
     async def test_逐跳重定向每跳重校验(self, monkeypatch):
         """302 → Location 指向私网 IP → 必须以 FetchError 终结（安全关键路径）。"""
         served = []
@@ -131,6 +144,31 @@ class TestFetch:
         # 首跳（公网）发生、第二跳（私网 Location）在 URL 层即被拦，未发起
         assert served == ["http://example.com/start"]
 
+    async def test_重定向协议切换拒绝(self, monkeypatch):
+        """302 → Location 换协议（ftp://）→ 第二跳 URL 层 FetchError。"""
+        served = []
+
+        def handler(request: httpx.Request) -> httpx.Response:
+            served.append(str(request.url))
+            return httpx.Response(302, headers={"Location": "ftp://evil/"})
+
+        monkeypatch.setattr(safe_fetch, "_make_client", _mock_client_factory(handler))
+        with pytest.raises(safe_fetch.FetchError):
+            await safe_fetch.fetch("http://example.com/start")
+        assert served == ["http://example.com/start"]
+
+    async def test_连接层私网解析拒绝_真实链路(self, monkeypatch):
+        """DNS rebinding 端到端钉位：URL 层查不出的私网目标（域名解析返回 10.x），
+        经真实 _make_client 的连接层必须拦下——只打桩 getaddrinfo，不打桩 connect_tcp，
+        证明校验先于任何连接发生。"""
+        async def fake_getaddrinfo(host, port, **kwargs):
+            return [(socket.AF_INET, socket.SOCK_STREAM, 6, "", ("10.66.0.9", port))]
+
+        monkeypatch.setattr(safe_fetch.anyio, "getaddrinfo", fake_getaddrinfo)
+        with pytest.raises(safe_fetch.FetchError) as exc_info:
+            await safe_fetch.fetch("http://rebinding.example.com/x")
+        assert isinstance(exc_info.value.__cause__, safe_fetch.BlockedAddressError)
+
     async def test_重定向上限5跳(self, monkeypatch):
         """>5 跳 302 链 → FetchError。"""
         calls = []