From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 25 Sep 2023 15:50:28 +0000 (-0400)
Subject: Limit to_tsvector_byid's initial array allocation to something sane.
X-Git-Tag: REL_12_17~71
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4a81ed29d3c956ad11354c0dc4514f5af4a0d8d7;p=thirdparty%2Fpostgresql.git

Limit to_tsvector_byid's initial array allocation to something sane.

The initial estimate of the number of distinct ParsedWords is just
that: an estimate.  Don't let it exceed what palloc is willing to
allocate.  If in fact we need more entries, we'll eventually fail
trying to enlarge the array.  But if we don't, this allows success on
inputs that currently draw "invalid memory alloc request size".

Per bug #18080 from Uwe Binder.  Back-patch to all supported branches.

Discussion: https://postgr.es/m/18080-d5c5e58fef8c99b7@postgresql.org
---

diff --git a/src/backend/tsearch/to_tsany.c b/src/backend/tsearch/to_tsany.c
index 6baee8e1558..d9619c576e7 100644
--- a/src/backend/tsearch/to_tsany.c
+++ b/src/backend/tsearch/to_tsany.c
@@ -242,6 +242,8 @@ to_tsvector_byid(PG_FUNCTION_ARGS)
 												 * number */
 	if (prs.lenwords < 2)
 		prs.lenwords = 2;
+	else if (prs.lenwords > MaxAllocSize / sizeof(ParsedWord))
+		prs.lenwords = MaxAllocSize / sizeof(ParsedWord);
 	prs.curwords = 0;
 	prs.pos = 0;
 	prs.words = (ParsedWord *) palloc(sizeof(ParsedWord) * prs.lenwords);