fix(presets): harden preset URL installs against unsafe redirects (#2911)

* Harden preset URL installs against unsafe redirects

Preset URL installs already rejected non-HTTPS source URLs, but the authenticated opener follows redirects. Validate the final response URL before writing the ZIP, preserve GitHub release asset URL resolution after the preset command module split, stream the response to disk, and keep catalog config serialization on safe YAML output.

Constraint: open_url follows redirects, so source URL validation alone does not constrain the downloaded target

Rejected: Keep response.read() for simplicity | large preset downloads should not be buffered entirely in memory

Confidence: high

Scope-risk: narrow

Directive: Keep preset URL policy aligned with workflow installer redirect validation

Tested: uvx ruff check src/specify_cli/__init__.py src/specify_cli/presets/__init__.py src/specify_cli/presets/_commands.py tests/test_presets.py

Tested: uv run pytest tests/test_presets.py -q

Not-tested: Real network redirect integration against a live HTTP server

Co-authored-by: OmX <omx@oh-my-codex.dev>

* Reject malformed preset download URLs

Preset downloads should fail early when a URL lacks a hostname, even if the scheme is HTTPS. The redirect error now describes any disallowed target instead of implying that only non-HTTPS redirects are blocked.

* Prevent credentialed preset redirects from downgrading transport

Preset URL downloads already checked the final URL after urllib followed redirects, but that was too late for authenticated requests because same-host redirects could preserve Authorization during the redirect itself. The authenticated HTTP helper now supports an opt-in redirect validator, and preset downloads use it to reject disallowed redirect targets before following them. The redirect auth handlers also stop preserving credentials across HTTPS to non-HTTPS downgrades as defense in depth.

* test(presets): 修复 URL 解析测试 mock 缺少 redirect_validator 参数

重定向安全加固为 open_url 新增 redirect_validator 参数，
两处 fake_open_url mock 签名未同步导致 TypeError。
补齐参数后全部 3717 个测试通过。

---------

Co-authored-by: OmX <omx@oh-my-codex.dev>

Author: darion-yaphet

src/specify_cli/__init__.py

@@ -684,16 +684,44 @@ def preset_add(
 
         elif from_url:
             # Validate URL scheme before downloading
+            from ipaddress import ip_address
             from urllib.parse import urlparse as _urlparse
+
             _parsed = _urlparse(from_url)
-            _is_localhost = _parsed.hostname in ("localhost", "127.0.0.1", "::1")
-            if _parsed.scheme != "https" and not (_parsed.scheme == "http" and _is_localhost):
-                console.print(f"[red]Error:[/red] URL must use HTTPS (got {_parsed.scheme}://). HTTP is only allowed for localhost.")
+
+            def _is_allowed_download_url(parsed_url):
+                host = parsed_url.hostname
+                if not host:
+                    return False
+                is_loopback = host == "localhost"
+                if not is_loopback:
+                    try:
+                        is_loopback = ip_address(host).is_loopback
+                    except ValueError:
+                        # Host is not an IP literal (e.g., a regular hostname); treat as non-loopback.
+                        pass
+                return parsed_url.scheme == "https" or (parsed_url.scheme == "http" and is_loopback)
+
+            def _validate_download_redirect(old_url, new_url):
+                if not _is_allowed_download_url(_urlparse(new_url)):
+                    import urllib.error
+
+                    raise urllib.error.URLError(
+                        "redirect target must use HTTPS with a hostname, "
+                        "or HTTP for localhost/loopback"
+                    )
+
+            if not _is_allowed_download_url(_parsed):
+                console.print(
+                    "[red]Error:[/red] URL must use HTTPS with a hostname, "
+                    "or HTTP for localhost/loopback."
+                )
                 raise typer.Exit(1)
 
             console.print(f"Installing preset from [cyan]{from_url}[/cyan]...")
             import urllib.error
             import tempfile
+            import shutil
 
             with tempfile.TemporaryDirectory() as tmpdir:
                 zip_path = Path(tmpdir) / "preset.zip"
@@ -707,8 +735,25 @@ def preset_add(
                         from_url = _resolved_from_url
                         _preset_extra_headers = {"Accept": "application/octet-stream"}
 
-                    with _open_url(from_url, timeout=60, extra_headers=_preset_extra_headers) as response:
-                        zip_path.write_bytes(response.read())
+                    with _open_url(
+                        from_url,
+                        timeout=60,
+                        extra_headers=_preset_extra_headers,
+                        redirect_validator=_validate_download_redirect,
+                    ) as response:
+                        final_url = response.geturl() if hasattr(response, "geturl") else from_url
+                        if not _is_allowed_download_url(_urlparse(final_url)):
+                            console.print(
+                                "[red]Error:[/red] Preset URL redirected to a disallowed URL: "
+                                f"{final_url}. Redirect targets must use HTTPS with a hostname, "
+                                "or HTTP for localhost/loopback."
+                            )
+                            raise typer.Exit(1)
+                        with zip_path.open("wb") as output:
+                            try:
+                                shutil.copyfileobj(response, output)
+                            except TypeError:
+                                output.write(response.read())
                 except urllib.error.URLError as e:
                     console.print(f"[red]Error:[/red] Failed to download: {e}")
                     raise typer.Exit(1)
@@ -1186,7 +1231,7 @@ def preset_catalog_add(
     })
 
     config["catalogs"] = catalogs
-    config_path.write_text(yaml.dump(config, default_flow_style=False, sort_keys=False, allow_unicode=True), encoding="utf-8")
+    config_path.write_text(yaml.safe_dump(config, default_flow_style=False, sort_keys=False, allow_unicode=True), encoding="utf-8")
 
     install_label = "install allowed" if install_allowed else "discovery only"
     console.print(f"\n[green]✓[/green] Added catalog '[bold]{name}[/bold]' ({install_label})")
@@ -1226,7 +1271,7 @@ def preset_catalog_remove(
         raise typer.Exit(1)
 
     config["catalogs"] = catalogs
-    config_path.write_text(yaml.dump(config, default_flow_style=False, sort_keys=False, allow_unicode=True), encoding="utf-8")
+    config_path.write_text(yaml.safe_dump(config, default_flow_style=False, sort_keys=False, allow_unicode=True), encoding="utf-8")
 
     console.print(f"[green]✓[/green] Removed catalog '{name}'")
     if not catalogs:

src/specify_cli/authentication/http.py

@@ -14,6 +14,7 @@
 import urllib.error
 import urllib.request
 from fnmatch import fnmatch
+from typing import Callable
 from urllib.parse import urlparse
 
 from . import get_provider
@@ -56,22 +57,36 @@ def _hostname_in_hosts(hostname: str, hosts: tuple[str, ...]) -> bool:
     return any(p == hostname or fnmatch(hostname, p) for p in hosts)
 
 
+RedirectValidator = Callable[[str, str], None]
+
+
 class _StripAuthOnRedirect(urllib.request.HTTPRedirectHandler):
-    """Drop ``Authorization`` when a redirect leaves the entry's declared hosts."""
+    """Drop ``Authorization`` when a redirect leaves trusted hosts or downgrades."""
 
-    def __init__(self, hosts: tuple[str, ...]) -> None:
+    def __init__(
+        self,
+        hosts: tuple[str, ...],
+        redirect_validator: RedirectValidator | None = None,
+    ) -> None:
         super().__init__()
         self._hosts = hosts
+        self._redirect_validator = redirect_validator
 
     def redirect_request(self, req, fp, code, msg, headers, newurl):
+        if self._redirect_validator is not None:
+            self._redirect_validator(req.full_url, newurl)
+
         original_auth = (
             req.get_header("Authorization")
             or req.unredirected_hdrs.get("Authorization")
         )
         new_req = super().redirect_request(req, fp, code, msg, headers, newurl)
         if new_req is not None:
-            hostname = (urlparse(newurl).hostname or "").lower()
-            if _hostname_in_hosts(hostname, self._hosts):
+            old_scheme = urlparse(req.full_url).scheme
+            new_parsed = urlparse(newurl)
+            hostname = (new_parsed.hostname or "").lower()
+            is_https_downgrade = old_scheme == "https" and new_parsed.scheme != "https"
+            if _hostname_in_hosts(hostname, self._hosts) and not is_https_downgrade:
                 if original_auth:
                     new_req.add_unredirected_header("Authorization", original_auth)
             else:
@@ -103,7 +118,12 @@ def build_request(url: str, extra_headers: dict[str, str] | None = None) -> urll
     return urllib.request.Request(url, headers=headers)
 
 
-def open_url(url: str, timeout: int = 10, extra_headers: dict[str, str] | None = None):
+def open_url(
+    url: str,
+    timeout: int = 10,
+    extra_headers: dict[str, str] | None = None,
+    redirect_validator: RedirectValidator | None = None,
+):
     """Open *url* with config-driven auth, redirect stripping, and fallthrough.
 
     1. Find ``auth.json`` entries whose hosts match the URL.
@@ -113,6 +133,8 @@ def open_url(url: str, timeout: int = 10, extra_headers: dict[str, str] | None =
     5. Non-auth errors (404, 500, network) raise immediately.
 
     *extra_headers* (e.g. ``Accept``) are merged into every attempt.
+    *redirect_validator*, when provided, is called with ``(old_url, new_url)``
+    before following each redirect and may raise to reject the redirect.
     """
     entries = find_entries_for_url(url, _load_config())
 
@@ -135,7 +157,7 @@ def _make_req(auth_headers: dict[str, str]) -> urllib.request.Request:
             continue
 
         req = _make_req(provider.auth_headers(token, entry.auth))
-        opener = urllib.request.build_opener(_StripAuthOnRedirect(entry.hosts))
+        opener = urllib.request.build_opener(_StripAuthOnRedirect(entry.hosts, redirect_validator))
         try:
             return opener.open(req, timeout=timeout)
         except urllib.error.HTTPError as exc:
@@ -146,4 +168,7 @@ def _make_req(auth_headers: dict[str, str]) -> urllib.request.Request:
 
     # No entry worked (or none matched) — unauthenticated fallback
     req = _make_req({})
+    if redirect_validator is not None:
+        opener = urllib.request.build_opener(_StripAuthOnRedirect((), redirect_validator))
+        return opener.open(req, timeout=timeout)
     return urllib.request.urlopen(req, timeout=timeout)  # noqa: S310

tests/test_authentication.py

@@ -793,6 +793,35 @@ def test_redirect_outside_hosts_strips_auth(self):
         assert new_req.headers.get("Authorization") is None
         assert new_req.unredirected_hdrs.get("Authorization") is None
 
+    def test_https_to_http_same_host_redirect_strips_auth(self):
+        from specify_cli.authentication.http import _StripAuthOnRedirect
+        from urllib.request import Request
+        import io
+        handler = _StripAuthOnRedirect(("github.com",))
+        req = Request("https://github.com/org/repo", headers={"Authorization": "Bearer tok"})
+        new_req = handler.redirect_request(req, io.BytesIO(b""), 302, "Found", {},
+                                           "http://github.com/org/repo")
+        assert new_req is not None
+        assert new_req.headers.get("Authorization") is None
+        assert new_req.unredirected_hdrs.get("Authorization") is None
+
+    def test_redirect_validator_can_reject_before_following_redirect(self):
+        import urllib.error
+        from specify_cli.authentication.http import _StripAuthOnRedirect
+        from urllib.request import Request
+        import io
+
+        def reject_http(old_url, new_url):
+            if new_url.startswith("http://"):
+                raise urllib.error.URLError("scheme downgrade")
+
+        handler = _StripAuthOnRedirect(("github.com",), reject_http)
+        req = Request("https://github.com/org/repo", headers={"Authorization": "Bearer tok"})
+
+        with pytest.raises(urllib.error.URLError, match="scheme downgrade"):
+            handler.redirect_request(req, io.BytesIO(b""), 302, "Found", {},
+                                     "http://github.com/org/repo")
+
     def test_multi_hop_redirect_within_hosts_preserves_auth(self):
         """Auth survives a multi-hop redirect chain within allowed hosts."""
         from specify_cli.authentication.http import _StripAuthOnRedirect

tests/test_github_http.py

@@ -187,4 +187,4 @@ def capturing_open(url, timeout=None, extra_headers=None):
             capturing_open,
         )
         assert len(captured_urls) == 1
-        assert "releases/tags/v1%23beta" in captured_urls[0]
+        assert "releases/tags/v1%23beta" in captured_urls[0]