Additional DB sanitization functions

[markjaquith]

For places where we build complex SQL queries by hand or where we let PHP control things like column names, limits, and ORDER BY order, we need some functions to consistently sanitize this data.

Proposed:

sanitize_column($column name);
sanitize_limit($limit_string);
sanitize_orderby_direction($desc_or_asc);

Any others?

No Patch. Moved to 2.7

No patch moving to 2.9.

I fail to see the point. If so, we'd also need a sanitize_where, sanitize_join, sanitize_group_by, and, why not..., sanitize_subquery. In short, an SQL parser.

It's the plugin author's responsibility to make sure that whatever he adds is valid sql.