From: Jeff Davis <jdavis@postgresql.org>
Date: Mon, 13 Apr 2026 18:19:21 +0000 (-0700)
Subject: Fix overrun when comparing with unterminated ICU language string.
X-Git-Tag: REL_18_4~69
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6393259bd49db307c7113d70da355544479ee342;p=thirdparty%2Fpostgresql.git

Fix overrun when comparing with unterminated ICU language string.

The overrun was introduced in commit c4ff35f10.

Author: Andreas Karlsson <andreas@proxel.se>
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/96d80a47-f17f-42fa-82b1-2908efbd6541@gmail.com
Backpatch-through: 18
---

diff --git a/src/backend/utils/adt/pg_locale_icu.c b/src/backend/utils/adt/pg_locale_icu.c
index ff4541a64f3..4f401a28f0d 100644
--- a/src/backend/utils/adt/pg_locale_icu.c
+++ b/src/backend/utils/adt/pg_locale_icu.c
@@ -702,7 +702,7 @@ u_strFoldCase_default(UChar *dest, int32_t destCapacity,
 					  UErrorCode *pErrorCode)
 {
 	uint32		options = U_FOLD_CASE_DEFAULT;
-	char		lang[3];
+	char		lang[ULOC_LANG_CAPACITY];
 	UErrorCode	status;
 
 	/*
@@ -712,8 +712,8 @@ u_strFoldCase_default(UChar *dest, int32_t destCapacity,
 	 * languages to enable the option.
 	 */
 	status = U_ZERO_ERROR;
-	uloc_getLanguage(locale, lang, 3, &status);
-	if (U_SUCCESS(status))
+	uloc_getLanguage(locale, lang, ULOC_LANG_CAPACITY, &status);
+	if (U_SUCCESS(status) && status != U_STRING_NOT_TERMINATED_WARNING)
 	{
 		/*
 		 * The option name is confusing, but it causes u_strFoldCase to use