fix(db): restrict data/app.db to 0600 (#4420)

* fix(db): restrict data/app.db to 0600

app.db holds bearer-token hashes, bcrypt password hashes, and encrypted
provider keys but was created under the default umask (0644 -> world-readable),
unlike .app_key/vault/integrations which are already 0600 via safe_chmod.

init_db() now chmods the SQLite file to 0600 right after create_all (POSIX
only; no-op on Windows, skipped for Postgres / in-memory). Unconditional and
idempotent, so it also re-locks already-deployed 0644 installs on next
startup. The transient rollback journal inherits 0600 from the parent file at
creation - no sidecar handling needed; -wal/-shm don't exist until WAL is
enabled (#4409 C4) and inherit the same mode then.

Satisfies Rule B, unblocking #4413 and the vault/integration secret moves.
Mirrors src/secret_storage.py:43-45.

Verified: security + DB-permission suites pass; 6 pre-existing visual_report
failures (missing markdown/nh3 deps) are unrelated.

Closes #4407

* fix(db): harden SQLite path parsing and re-lock sidecars

Address review feedback on #4420.

P2: derive the file to chmod from engine.url (SQLAlchemy's parsed URL)
via _sqlite_db_path(), instead of DATABASE_URL.replace("sqlite:///", "").
A driver-qualified URL (sqlite+pysqlite://) or one carrying query args
(?cache=shared) previously slipped past the prefix check / string slice
and left the DB world-readable; the parsed path resolves correctly and
drops the query.

P3: re-lock stale -wal/-shm/-journal sidecars to 0o600 at startup. The
main file is chmod'd first, so any sidecar SQLite creates afterward
inherits 0o600, but a -wal/-shm left world-readable by an older 0o644
install (once WAL was enabled) could still expose DB pages. Absent
sidecars are the normal case, not an error.

Tests: unit-test _sqlite_db_path across driver/query/memory/postgres URL
forms, and a subprocess test asserting stale 0o644 -wal/-shm are
re-locked on startup.

* fix(db): handle sqlite file URI app db permissions

* fix(db): close remaining SQLite permission bypasses

---------

Co-authored-by: Ethan <23321960+0xLeathery@users.noreply.github.com>
Co-authored-by: Alexandre Teixeira <alexandremagteixeira@gmail.com>

core/database.py

@@ -3,13 +3,16 @@ import logging
 import sqlite3
 from datetime import datetime, timezone
 from pathlib import Path
+from typing import Optional
+from urllib.parse import unquote, urlparse
 from sqlalchemy import event, create_engine, Column, String, Text, Boolean, DateTime, Integer, ForeignKey, JSON, Index, func, text
-from sqlalchemy.engine import Engine
+from sqlalchemy.engine import Engine, make_url
 from sqlalchemy.types import TypeDecorator
 from sqlalchemy.ext.declarative import declarative_base, declared_attr
 from sqlalchemy.orm import relationship, sessionmaker, backref
 
 from src.runtime_paths import get_app_root
+from core.platform_compat import safe_chmod, IS_WINDOWS
 
 logger = logging.getLogger(__name__)
 
@@ -42,12 +45,28 @@ def _default_database_url() -> str:
 
 
 def _normalize_sqlite_url(url: str) -> str:
-    if not url.startswith("sqlite:///"):
+    """Resolve relative ordinary SQLite paths without rewriting URI filenames."""
+    try:
+        parsed = make_url(url)
+    except Exception:
         return url
-    db_path = url.replace("sqlite:///", "", 1)
-    if db_path == ":memory:" or os.path.isabs(db_path):
+
+    if parsed.get_backend_name() != "sqlite":
         return url
-    return f"sqlite:///{(Path(get_app_root()) / db_path).resolve().as_posix()}"
+
+    db_path = parsed.database
+    if (
+        not db_path
+        or db_path == ":memory:"
+        or str(db_path).lower().startswith("file:")
+        or os.path.isabs(str(db_path))
+    ):
+        return url
+
+    absolute_path = (Path(get_app_root()) / str(db_path)).resolve().as_posix()
+    return parsed.set(database=absolute_path).render_as_string(
+        hide_password=False
+    )
 
 
 # Get database URL from environment, default to SQLite in DATA_DIR
@@ -59,6 +78,59 @@ engine = create_engine(
     connect_args={"check_same_thread": False} if "sqlite" in DATABASE_URL else {}
 )
 
+
+# Sidecar files SQLite can create next to the main DB. -journal is the default
+# rollback journal; -wal/-shm appear once WAL is enabled. Each can hold copies of
+# secret-bearing pages, so they get the same 0o600 lockdown as the DB itself.
+_SQLITE_SIDECARS = ("-journal", "-wal", "-shm")
+
+
+def _sqlite_db_path(url) -> Optional[str]:
+    """Return the filesystem path for a file-backed SQLite URL.
+
+    SQLite query parameters such as ``mode=memory`` only affect filename
+    semantics when SQLAlchemy enables URI handling with ``uri=true``. Ordinary
+    file URLs must therefore remain file-backed even when they contain a query
+    parameter named ``mode``.
+
+    For SQLite ``file:`` URIs, an empty authority or ``localhost`` identifies a
+    local path. Other authorities are retained as UNC-style paths.
+    """
+    if url.get_backend_name() != "sqlite":
+        return None
+
+    db_path = url.database
+    if not db_path or db_path == ":memory:":
+        return None
+
+    db_path = str(db_path)
+    query = {
+        str(key).lower(): str(value).strip().lower()
+        for key, value in dict(getattr(url, "query", {}) or {}).items()
+    }
+    uri_enabled = query.get("uri") in {"1", "true", "yes", "on"}
+    is_file_uri = db_path.lower().startswith("file:")
+
+    if not uri_enabled or not is_file_uri:
+        return db_path
+
+    if (
+        db_path.lower().startswith("file::memory:")
+        or query.get("mode") == "memory"
+    ):
+        return None
+
+    parsed = urlparse(db_path)
+    fs_path = parsed.path or ""
+    if not fs_path or fs_path == ":memory:":
+        return None
+
+    authority = parsed.netloc
+    if authority and authority.lower() != "localhost":
+        fs_path = f"//{authority}{fs_path}"
+
+    return unquote(fs_path)
+
 # Create session factory
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
@@ -1819,6 +1891,41 @@ def init_db():
     """
     _migrate_model_endpoints()
     Base.metadata.create_all(bind=engine)
+    # Lock the DB file (and any SQLite sidecars) to 0o600 — it holds bearer-token
+    # + bcrypt hashes and encrypted provider keys. POSIX only; safe_chmod no-ops
+    # on Windows (ACL-restricted profile dir) and the path helper returns None for
+    # Postgres / in-memory. Must stay AFTER create_all: the file is born here at
+    # the umask default, and nothing below resets the mode. The path comes from
+    # engine.url (SQLAlchemy's parsed URL), so a driver-qualified or query-tagged
+    # DATABASE_URL still resolves to the real file instead of slipping through.
+    db_path = _sqlite_db_path(engine.url)
+    if db_path is not None:
+        # Fail closed-loud on the main file: this is the only access control on
+        # it, so if the chmod genuinely fails (read-only FS, foreign owner) an
+        # operator should hear about it. safe_chmod also returns False as a
+        # Windows no-op, so guard on IS_WINDOWS to avoid a spurious warning there.
+        if not safe_chmod(db_path, 0o600) and not IS_WINDOWS:
+            logger.warning(
+                "Could not restrict %s to 0o600; it holds secrets and may be "
+                "world-readable. Check filesystem permissions and ownership.",
+                db_path,
+            )
+        # Re-lock any sidecars present at startup. New ones inherit the main
+        # file's mode (now 0o600, since we set it first), and they're usually
+        # absent here, but a stale -wal/-shm/-journal left by an older 0o644
+        # install could still expose secret pages. Absent sidecars are the
+        # normal case, not an error — only a failed chmod warrants a warning.
+        for suffix in _SQLITE_SIDECARS:
+            sidecar = db_path + suffix
+            if (
+                os.path.exists(sidecar)
+                and not safe_chmod(sidecar, 0o600)
+                and not IS_WINDOWS
+            ):
+                logger.warning(
+                    "Could not restrict %s to 0o600; it may expose DB pages.",
+                    sidecar,
+                )
     _migrate_add_hidden_models_column()
     _migrate_add_cached_models_column()
     _migrate_add_pinned_models_column()