From de9f4c3bb798a40cf81cb9e90be28b05a21bda39 Mon Sep 17 00:00:00 2001
From: Matthew Kim <38759997+friendlymatthew@users.noreply.github.com>
Date: Tue, 9 Jul 2024 18:25:10 -0400
Subject: [PATCH 3/4] Handle overflows in do_to_timestamp().

This commit handles overflow when formatting timestamps with the 'CC'
pattern.
---
 src/backend/utils/adt/formatting.c     | 25 +++++++++++++++++++++++--
 src/test/regress/expected/horology.out |  2 ++
 src/test/regress/sql/horology.sql      |  1 +
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 8736ada4be..32470665cf 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -77,6 +77,7 @@
 
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
+#include "common/int.h"
 #include "common/unicode_case.h"
 #include "common/unicode_category.h"
 #include "mb/pg_wchar.h"
@@ -4839,11 +4840,31 @@ do_to_timestamp(text *date_txt, text *fmt, Oid collid, bool std,
 		if (tmfc.bc)
 			tmfc.cc = -tmfc.cc;
 		if (tmfc.cc >= 0)
+		{
 			/* +1 because 21st century started in 2001 */
-			tm->tm_year = (tmfc.cc - 1) * 100 + 1;
+			/* tm->tm_year = (tmfc.cc - 1) * 100 + 1; */
+			if (pg_mul_s32_overflow((tmfc.cc - 1), 100, &tm->tm_year) ||
+				pg_add_s32_overflow(tm->tm_year, 1, &tm->tm_year))
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+						 errmsg("date out of range: \"%s\"",
+								text_to_cstring(date_txt))));
+			}
+		}
 		else
+		{
 			/* +1 because year == 599 is 600 BC */
-			tm->tm_year = tmfc.cc * 100 + 1;
+			/* tm->tm_year = tmfc.cc * 100 + 1; */
+			if (pg_mul_s32_overflow(tmfc.cc, 100, &tm->tm_year) ||
+				pg_add_s32_overflow(tm->tm_year, 1, &tm->tm_year))
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+						 errmsg("date out of range: \"%s\"",
+								text_to_cstring(date_txt))));
+			}
+		}
 		fmask |= DTK_M(YEAR);
 	}
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 241713cc51..311c688f89 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -3778,6 +3778,8 @@ SELECT to_date('0000-02-01','YYYY-MM-DD');  -- allowed, though it shouldn't be
  02-01-0001 BC
 (1 row)
 
+SELECT to_date('100000000', 'CC');
+ERROR:  date out of range: "100000000"
 -- to_char's TZ format code produces zone abbrev if known
 SELECT to_char('2012-12-12 12:00'::timestamptz, 'YYYY-MM-DD HH:MI:SS TZ');
          to_char         
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index e5cf12ff63..12a035cf57 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -660,6 +660,7 @@ SELECT to_date('2016 365', 'YYYY DDD');  -- ok
 SELECT to_date('2016 366', 'YYYY DDD');  -- ok
 SELECT to_date('2016 367', 'YYYY DDD');
 SELECT to_date('0000-02-01','YYYY-MM-DD');  -- allowed, though it shouldn't be
+SELECT to_date('100000000', 'CC');
 
 -- to_char's TZ format code produces zone abbrev if known
 SELECT to_char('2012-12-12 12:00'::timestamptz, 'YYYY-MM-DD HH:MI:SS TZ');
-- 
2.39.3 (Apple Git-146)