Fix SSRF access (#943)

tests/core/test_image_cache.py

@@ -5,15 +5,67 @@ import requests
 from shelfmark.core.image_cache import ImageCacheService
 
 
+def test_fetch_and_cache_rejects_backslash_authority_bypass_before_request(
+    tmp_path, monkeypatch
+) -> None:
+    cache = ImageCacheService(tmp_path)
+    calls = []
+
+    def fake_get(url, **_kwargs):
+        calls.append(url)
+        raise AssertionError("unsafe URL should not be requested")
+
+    monkeypatch.setattr("shelfmark.core.image_cache.requests.get", fake_get)
+
+    assert cache.fetch_and_cache("cover-ssrf", "http://127.0.0.1:6666\\@1.1.1.1") is None
+    assert calls == []
+    assert "cover-ssrf" not in cache._index
+
+
+def test_is_safe_url_rejects_encoded_separator_in_authority() -> None:
+    assert ImageCacheService._is_safe_url("http://127.0.0.1:6666%5c@1.1.1.1") is False
+    assert ImageCacheService._is_safe_url("http://127.0.0.1:6666%2f@1.1.1.1") is False
+
+
 def test_is_safe_url_rejects_invalid_ipv6_url() -> None:
     assert ImageCacheService._is_safe_url("http://[") is False
 
 
+def test_fetch_and_cache_blocks_unsafe_redirect(tmp_path, monkeypatch) -> None:
+    cache = ImageCacheService(tmp_path)
+
+    def fake_getaddrinfo(hostname, *_args, **_kwargs):
+        addresses = {
+            "example.com": "93.184.216.34",
+            "127.0.0.1": "127.0.0.1",
+        }
+        return [(None, None, None, None, (addresses[hostname], 0))]
+
+    class RedirectResponse:
+        is_redirect = True
+        headers = {"location": "http://127.0.0.1/cover.jpg"}
+
+        def close(self):
+            return None
+
+    calls = []
+
+    def fake_get(url, **_kwargs):
+        calls.append(url)
+        return RedirectResponse()
+
+    monkeypatch.setattr("shelfmark.core.image_cache.socket.getaddrinfo", fake_getaddrinfo)
+    monkeypatch.setattr("shelfmark.core.image_cache.requests.get", fake_get)
+
+    assert cache.fetch_and_cache("cover-redirect", "https://example.com/cover.jpg") is None
+    assert calls == ["https://example.com/cover.jpg"]
+    assert "cover-redirect" not in cache._index
+
+
 def test_fetch_and_cache_returns_none_on_request_exception(tmp_path, monkeypatch) -> None:
     cache = ImageCacheService(tmp_path)
-    monkeypatch.setattr(cache, "_is_safe_url", lambda _url: True)
 
-    def fake_get(*args, **kwargs):
+    def fake_get(*_args, **_kwargs):
         raise requests.exceptions.TooManyRedirects("too many redirects")
 
     monkeypatch.setattr("shelfmark.core.image_cache.requests.get", fake_get)