fix: widen secure_parent_dir to skip entire install tree

Replace hardcoded /opt/hermes check with dynamic install-tree detection
using Path(__file__).resolve().parent. This catches ALL install paths
(Docker /opt/hermes, apt /usr/local/lib/hermes-agent, git clone, custom)
instead of just the Docker image path. Also covers subdirectories of the
install tree, not just the top-level dir.

Add regression test test_install_tree_skipped to verify both the install
root and subdirectories are excluded from chmod.

Add contributor email mapping for bradmarshall987.

Follow-up to PR #93050 by @bradmarshall987.

contributors/emails/bradmarshall987@users.noreply.github.com

@@ -0,0 +1 @@
+bradmarshall987

hermes_constants.py

@@ -350,6 +350,11 @@ _HERMES_NODE_TARGET_MAJOR = int(os.environ.get("HERMES_NODE_TARGET_MAJOR", "22")
 _managed_node_heal_attempted = False
 _NODE_BOOTSTRAP_SCRIPT = Path(__file__).resolve().parent / "scripts" / "lib" / "node-bootstrap.sh"
 
+# Install tree root (this file lives at <install_root>/hermes_constants.py).
+# Used by secure_parent_dir() to skip chmod on the install dir — chmodding it
+# 0700 breaks hermes-user traversal in Docker (UID 10000). See #25821, #93050.
+_INSTALL_ROOT = Path(__file__).resolve().parent
+
 
 def node_tool_runnable(path: str | None) -> bool:
     """Return True only when *path* is a Node/npm/npx binary that actually runs.
@@ -1023,14 +1028,10 @@ def secure_parent_dir(path: Path) -> None:
     # Refuse root and its direct children (/usr, /home, /var, /tmp, …).
     if parent == Path("/") or len(parent.parts) < 3:
         return
-    # Refuse /opt/hermes. The install dir lives on the image layer;
-    # chmodding it to 0700 breaks hermes-user traversal and produces
-    # spurious "Permission denied" on every new exec until manual
-    # `chmod 0755 /opt/hermes`. Reproducer: any auth write to a file
-    # directly under /opt/hermes (e.g. /opt/hermes/auth.json when
-    # HERMES_HOME resolves there) triggers the 0700 chmod and locks
-    # out UID 10000. See issue #25821 follow-up.
-    if str(parent) == "/opt/hermes":
+    # Refuse the install tree root. chmodding it 0700 breaks hermes-user
+    # traversal in Docker (UID 10000) and any other install where the
+    # runtime user doesn't own the install dir. See #25821, #93050.
+    if parent == _INSTALL_ROOT or _INSTALL_ROOT in parent.parents:
         return
     try:
         os.chmod(parent, 0o700)

tests/test_hermes_constants.py

@@ -560,8 +560,29 @@ class TestSecureParentDir:
         secure_parent_dir(Path("/foo"))
         assert called_with == []
 
+    def test_install_tree_skipped(self, monkeypatch):
+        """Parent dir equal to (or inside) the install tree must NOT be chmod'd.
 
+        Regression test for #93050: secure_parent_dir() chmod'd /opt/hermes to
+        0700 because it has 3 path parts and passed the ``< 3`` guard, locking
+        out UID 10000 (hermes user) from traversing the install dir.
+        """
+        install_root = Path(hermes_constants.__file__).resolve().parent
 
+        # Directly under the install root (e.g. /opt/hermes/auth.json)
+        target = install_root / "auth.json"
+        called_with = []
+        monkeypatch.setattr(os, "chmod", lambda p, m: called_with.append((str(p), m)))
+        secure_parent_dir(target)
+        assert called_with == [], "must not chmod the install root"
+
+        # Inside a subdirectory of the install root
+        sub = install_root / "subdir"
+        target2 = sub / "auth.json"
+        called_with2 = []
+        monkeypatch.setattr(os, "chmod", lambda p, m: called_with2.append((str(p), m)))
+        secure_parent_dir(target2)
+        assert called_with2 == [], "must not chmod dirs inside the install tree"
 
     @pytest.mark.require_symlinks
     def test_symlink_resolved(self, tmp_path, monkeypatch):