On Wed, Mar 23, 2022 at 1:16 AM Michael Paquier <michael@paquier.xyz> wrote:
> As far as I can see, this is
> also possible in bt_page_items_bytea(), gist_page_opaque_info(),
> gin_metapage_info() and gin_page_opaque_info(). All those code paths
> should be protected with some checks on PageGetSpecialSize(), I
> guess, before attempting to read the special area of the page. Hash
> indexes are protected by checking the expected size of the special
> area, and one code path of btree relies on the opened relation to be a
> btree index.
amcheck's palloc_btree_page() function validates that an 8KiB page is
in fact an nbtree page, in a maximally paranoid way. Might be an
example worth following here.
--
Peter Geoghegan