fix(file-safety): deny reads of Google OAuth tokens (#30972)

agent/file_safety.py

@@ -153,11 +153,11 @@ def get_read_block_error(path: str) -> Optional[str]:
         carrier.
       * Credential / secret stores under HERMES_HOME and the global Hermes
         root: ``auth.json``, ``auth.lock``, ``.anthropic_oauth.json``,
-        ``.env``, ``webhook_subscriptions.json``, and anything under
+        ``.env``, ``webhook_subscriptions.json``, ``auth/google_oauth.json``,
-        ``mcp-tokens/``. These hold plaintext provider keys, OAuth tokens,
+        and anything under ``mcp-tokens/``. These hold plaintext provider keys,
-        and HMAC secrets that the agent never needs to read directly —
+        OAuth tokens, and HMAC secrets that the agent never needs to read
-        provider tools / gateway adapters consume them through internal
+        directly — provider tools / gateway adapters consume them through
-        channels.
+        internal channels.
 
     **This is NOT a security boundary.** The terminal tool runs as the
     same OS user with shell access; the agent can still ``cat auth.json``
@@ -222,6 +222,7 @@ def get_read_block_error(path: str) -> Optional[str]:
         ".anthropic_oauth.json",
         ".env",
         "webhook_subscriptions.json",
+        os.path.join("auth", "google_oauth.json"),
     )
     for hd in hermes_dirs:
         for name in credential_file_names:

tests/agent/test_file_safety_credentials.py

@@ -66,6 +66,16 @@ def test_anthropic_oauth_json_blocked(fake_home):
     assert "credential store" in err
 
 
+def test_google_oauth_json_blocked(fake_home):
+    """Gemini OAuth tokens live under auth/google_oauth.json — blocked."""
+    from agent.file_safety import get_read_block_error
+
+    oauth = _create(fake_home, Path("auth") / "google_oauth.json")
+    err = get_read_block_error(str(oauth))
+    assert err is not None
+    assert "credential store" in err
+
+
 def test_arbitrary_hermes_home_file_not_blocked(fake_home):
     """Non-credential files inside HERMES_HOME stay readable."""
     from agent.file_safety import get_read_block_error
@@ -149,6 +159,37 @@ def test_read_file_tool_blocks_relative_path_under_terminal_cwd(
     assert "credential store" in out["error"]
 
 
+def test_read_file_tool_blocks_nested_google_oauth_path(
+    fake_home, tmp_path, monkeypatch
+):
+    """The real read_file tool must not return Gemini OAuth token material."""
+    import json
+
+    import tools.file_tools as ft
+
+    oauth = _create(fake_home, Path("auth") / "google_oauth.json")
+    oauth.write_text(
+        json.dumps(
+            {
+                "refresh": "REFRESH_TOKEN_MARKER",
+                "access": "ACCESS_TOKEN_MARKER",
+                "email": "user@example.com",
+            }
+        ),
+        encoding="utf-8",
+    )
+    monkeypatch.chdir(tmp_path)
+    monkeypatch.setattr(
+        ft, "_get_live_tracking_cwd", lambda task_id="default": None
+    )
+
+    out = json.loads(ft.read_file_tool(str(oauth), task_id="google-oauth-test"))
+    assert "error" in out
+    assert "credential store" in out["error"]
+    assert "REFRESH_TOKEN_MARKER" not in json.dumps(out)
+    assert "ACCESS_TOKEN_MARKER" not in json.dumps(out)
+
+
 # ---------------------------------------------------------------------------
 # Widening: .env, webhook_subscriptions.json, mcp-tokens/
 # ---------------------------------------------------------------------------
@@ -222,6 +263,11 @@ def test_identically_named_files_outside_hermes_home_not_blocked(
             f"{rel} outside HERMES_HOME should NOT be blocked"
         )
 
+    google_oauth = project / "auth" / "google_oauth.json"
+    google_oauth.parent.mkdir()
+    google_oauth.write_text("not really a token", encoding="utf-8")
+    assert get_read_block_error(str(google_oauth)) is None
+
     tokens = project / "mcp-tokens"
     tokens.mkdir()
     tok_file = tokens / "token.json"
@@ -229,6 +275,14 @@ def test_identically_named_files_outside_hermes_home_not_blocked(
     assert get_read_block_error(str(tok_file)) is None
 
 
+def test_non_secret_auth_subtree_file_not_blocked(fake_home):
+    """Only the known Google OAuth token path is blocked, not all auth/*."""
+    from agent.file_safety import get_read_block_error
+
+    note = _create(fake_home, Path("auth") / "notes.json")
+    assert get_read_block_error(str(note)) is None
+
+
 def test_config_yaml_not_blocked(fake_home):
     """config.yaml is NOT a credential file — agent should still be
     able to read it for debugging.  (Writes are denied separately by
@@ -268,6 +322,14 @@ def test_profile_mode_blocks_root_credentials(tmp_path, monkeypatch):
     root_env.write_text("x")
     assert "credential store" in (get_read_block_error(str(root_env)) or "")
 
+    # Root-level Google OAuth token store: blocked too
+    root_google_oauth = root / "auth" / "google_oauth.json"
+    root_google_oauth.parent.mkdir(parents=True, exist_ok=True)
+    root_google_oauth.write_text("x")
+    assert "credential store" in (
+        get_read_block_error(str(root_google_oauth)) or ""
+    )
+
     # Root-level mcp-tokens: blocked
     root_tok = root / "mcp-tokens" / "gh.json"
     root_tok.parent.mkdir(parents=True, exist_ok=True)