From: David Rowley <drowley@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Add Asserts to validate prevbit values in bms_prev_member
Date: Fri, 15 Aug 2025 04:33:36 +0000
Message-ID: <E1umm8G-000cy8-13@gemulon.postgresql.org> (raw)
Add Asserts to validate prevbit values in bms_prev_member
bms_prev_member() could attempt to access memory outside of the words[]
array in cases where the prevbit was a number < -1 or > a->nwords *
BITS_PER_BITMAPWORD + 1.
Here we add the Asserts to help draw attention to bogus callers so we're
more likely to catch them during development.
In passing, fix wording of bms_prev_member's header comment which talks
about how we expect the callers to ensure only valid prevbit values are
used.
Author: Greg Burd <greg@burd.me>
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/2000A717-1FFE-4031-827B-9330FB2E9065%40getmailspring.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/b4632883d44eae892e28dafbf674e6ac3dfd824d
Modified Files
--------------
src/backend/nodes/bitmapset.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
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To: pgsql-committers@postgresql.org
Cc: drowley@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Add Asserts to validate prevbit values in bms_prev_member
In-Reply-To: <E1umm8G-000cy8-13@gemulon.postgresql.org>
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