harden: bound HTTP reads and enforce strict redirects (#3140)

* harden: bound HTTP reads and enforce strict redirects

Add a shared _download_security module (read_response_limited,
is_https_or_localhost_http, size constants) and route the GitHub release
and Azure DevOps token network reads through bounded reads so an oversized
response can't exhaust memory.

Add a strict_redirects mode to authentication.open_url: the redirect handler
now rejects any redirect whose target isn't HTTPS (or HTTP to localhost),
composing with the existing per-hop redirect_validator and auth-stripping.
The Azure DevOps token POST is routed through that handler so a 307/308
cannot forward the client_secret body to a non-HTTPS host.

Assisted-by: Codex (model: GPT-5, autonomous)

* test: align HTTP fakes with bounded reads

Assisted-by: Codex (model: GPT-5, autonomous)

* fix: tolerate invalid token response encoding

Assisted-by: Codex (model: GPT-5, autonomous)

* test: align GHES fakes with bounded reads

Assisted-by: Codex (model: GPT-5, autonomous)

* test: reuse shared upgrade HTTP response helper

Assisted-by: Codex (model: GPT-5, autonomous)

* fix: include rejected redirect target in error

Assisted-by: Codex (model: GPT-5, autonomous)

* fix: enforce strict redirects by default

Assisted-by: Codex (model: GPT-5, autonomous)

* fix: close redirect credential and SSRF gaps

Assisted-by: Codex (model: GPT-5, autonomous)

src/specify_cli/authentication/azure_devops.py

@@ -8,6 +8,7 @@ import os
 import subprocess
 from typing import TYPE_CHECKING
 
+from .._download_security import MAX_JSON_METADATA_BYTES, read_response_limited
 from .base import AuthProvider
 
 if TYPE_CHECKING:
@@ -17,6 +18,10 @@ if TYPE_CHECKING:
 _ADO_RESOURCE_ID = "499b84ac-1321-427f-aa17-267ca6975798"
 
 
+class _TokenResponseTooLarge(Exception):
+    """Raised when an Azure AD token response exceeds the bounded read limit."""
+
+
 class AzureDevOpsAuth(AuthProvider):
     """Azure DevOps authentication provider.
 
@@ -119,9 +124,38 @@ class AzureDevOpsAuth(AuthProvider):
             headers={"Content-Type": "application/x-www-form-urlencoded"},
         )
         try:
-            with urllib.request.urlopen(req, timeout=30) as resp:  # noqa: S310
-                payload = _json.loads(resp.read().decode("utf-8"))
+            from specify_cli.authentication.http import _StripAuthOnRedirect
+
+            def reject_token_redirect(_old_url: str, new_url: str) -> None:
+                # A 307/308 redirect preserves this POST body, including the
+                # client_secret. Refuse every redirect so credentials cannot
+                # leave the fixed Microsoft token endpoint.
+                raise urllib.error.URLError(
+                    f"Azure AD token request must not be redirected to {new_url}"
+                )
+
+            opener = urllib.request.build_opener(
+                _StripAuthOnRedirect((), reject_token_redirect)
+            )
+            with opener.open(req, timeout=30) as resp:  # noqa: S310
+                payload = _json.loads(
+                    read_response_limited(
+                        resp,
+                        max_bytes=MAX_JSON_METADATA_BYTES,
+                        error_type=_TokenResponseTooLarge,
+                        label="Azure DevOps token response",
+                    ).decode("utf-8")
+                )
                 token = payload.get("access_token", "").strip()
                 return token or None
-        except (urllib.error.URLError, OSError, _json.JSONDecodeError, KeyError):
+        except (
+            urllib.error.URLError,
+            OSError,
+            _json.JSONDecodeError,
+            UnicodeDecodeError,
+            _TokenResponseTooLarge,
+        ):
+            # Network failure, malformed JSON, or an oversized response — fall
+            # through to the next strategy. Unrelated programming errors (other
+            # ValueErrors, KeyErrors) intentionally propagate so they surface.
             return None