pg_partman privilege escalation via SQL injection when inheriting template properties

pg_partman is a PostgreSQL extension that manages partitioned tables by time or ID. Prior to 5.5.0, inherit_template_properties() manually surrounds primary-key column names from pg_attribute.attname with double quotes without escaping embedded double-quote characters. A partman_user who owns a template table can create a crafted column name that breaks out of the generated ALTER TABLE ADD PRIMARY KEY identifier when the background worker applies the key to a child partition. The generated SQL then executes with pg_partman_bgw.role privileges, which default to PostgreSQL superuser, permitting database-wide compromise and operating-system command execution as the PostgreSQL service account. The crafted catalog identifier persists until removed and can trigger again during later partition creation. This issue is fixed in version 5.5.0.