47 lines
2.0 KiB
Python
47 lines
2.0 KiB
Python
 
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"""Row-Level Security for plugin-owned tables (SPEC §11.1 + privacy hardening).
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Per-user isolation for ``plg_*`` tables is enforced by Postgres, not by remembering
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a ``WHERE user_id = ?`` in every query. Each user-data table gets RLS enabled +
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forced, with a policy comparing ``user_id`` to the transaction-local GUC
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``app.current_user_id``. Plugin code reaches these tables only through
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``sdk.session(user_id)`` (see :mod:`app.plugins.db`), which drops to the
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least-privilege :data:`PLUGIN_ROLE` and binds that GUC — so even a query that
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forgets to filter cannot see or write another user's rows.
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Plugin migrations call :func:`enable_rls` right after creating a user-data table.
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"""
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from __future__ import annotations
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# NOLOGIN, non-superuser, NOBYPASSRLS role plugin sessions SET LOCAL ROLE into
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# (created by core migration 0014). RLS is skipped for superusers / table owners /
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# BYPASSRLS roles, so plugin access must run as this restricted role to be enforced.
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PLUGIN_ROLE = "webmail_plugin"
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_USER_CTX = "current_setting('app.current_user_id', true)::uuid"
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def rls_ddl(table: str, *, user_column: str = "user_id") -> list[str]:
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"""SQL statements that lock ``table`` to the current user (SPEC §11.1).
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Pure/testable: returns the DDL rather than executing it. ``FORCE`` makes even
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the table owner subject to the policy; ``WITH CHECK`` blocks inserting/updating
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rows for a different user."""
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policy = f"{table}_user_isolation"
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return [
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f"ALTER TABLE {table} ENABLE ROW LEVEL SECURITY",
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f"ALTER TABLE {table} FORCE ROW LEVEL SECURITY",
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f"CREATE POLICY {policy} ON {table} "
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f"USING ({user_column} = {_USER_CTX}) "
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f"WITH CHECK ({user_column} = {_USER_CTX})",
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f"GRANT SELECT, INSERT, UPDATE, DELETE ON {table} TO {PLUGIN_ROLE}",
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]
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def enable_rls(table: str, *, user_column: str = "user_id") -> None:
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"""Apply :func:`rls_ddl` via Alembic ``op`` — call from a plugin migration."""
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from alembic import op
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for statement in rls_ddl(table, user_column=user_column):
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op.execute(statement)
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