Feedback-ID: i0fe9450f:Fastmail
Date: Fri, 5 Jun 2026 08:17:15 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Ashutosh Sharma <ashu.coek88@gmail.com>
Cc: surya poondla <suryapoondla4@gmail.com>,
	"violin0613@tju.edu.cn" <violin0613@tju.edu.cn>,
	pgsql-bugs@postgresql.org
Subject: Re: Fw: Re: heap_force_common in contrib/pg_surgery/heap_surgery.c
 has an off by one stack buffer overflow
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On Thu, Jun 04, 2026 at 02:42:23PM +0530, Ashutosh Sharma wrote:
> These are admittedly small risks, but they are real ones. Keeping the
> array 1-based eliminates that entire class of potential confusion and
> makes the code easier to maintain going forward. I'd lean toward
> Surya's approach for that reason.

That depends on the code path involved:
- pruneheap.c has "processed" and "htsv", that use a +1 index to avoid
the substract, where we also worry about performance.
- heapam_handler.c has in_index, that uses a -1 index.

At the end, the first pattern is an outlier, we don't need to worry
about performance in pg_surgery, and we're talking about three lines
of code in pg_surgery to change (two for include_this_tid, one for the
assertion).  With all that in mind, I'd just do a -1 conversion and
call it a day.  :)
--
Michael

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