Horton

Re: Assert in pageinspect with NULL pages

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Michael Paquier <michael@paquier.xyz>
Cc: Alexander Lakhin <exclusion@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, Daria Lepikhova <d.lepikhova@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2022-03-25T03:54:14Z
Lists: pgsql-hackers 
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

Commits

  1. pageinspect: Fix handling of all-zero pages

  2. pageinspect: Add more sanity checks to prevent out-of-bound reads

  3. pageinspect: Fix handling of page sizes and AM types

  4. Teach pageinspect about nbtree deduplication.