From: Andy Heninger <andy.heninger@gmail.com>
Date: Fri, 24 Aug 2018 17:50:56 +0000 (-0700)
Subject: ICU-20079 int overflow in Gregorian Calendar. (#66)
X-Git-Tag: release-63-rc~105
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c28e714aac3bab93ec36ddffd0ee708b01f12a43;p=icu

ICU-20079 int overflow in Gregorian Calendar. (#66)
---

diff --git a/icu4c/source/i18n/gregocal.cpp b/icu4c/source/i18n/gregocal.cpp
index 0485cca7cd9..a4a464626a8 100644
--- a/icu4c/source/i18n/gregocal.cpp
+++ b/icu4c/source/i18n/gregocal.cpp
@@ -541,8 +541,8 @@ int32_t GregorianCalendar::handleComputeMonthStart(int32_t eyear, int32_t month,
     }
 
     UBool isLeap = eyear%4 == 0;
-    int32_t y = eyear-1;
-    int32_t julianDay = 365*y + ClockMath::floorDivide(y, 4) + (kJan1_1JulianDay - 3);
+    int64_t y = (int64_t)eyear-1;
+    int64_t julianDay = 365*y + ClockMath::floorDivide(y, (int64_t)4) + (kJan1_1JulianDay - 3);
 
     nonConstThis->fIsGregorian = (eyear >= fGregorianCutoverYear);
 #if defined (U_DEBUG_CAL)
diff --git a/icu4c/source/i18n/gregoimp.h b/icu4c/source/i18n/gregoimp.h
index afaacda0b41..4fd868f4150 100644
--- a/icu4c/source/i18n/gregoimp.h
+++ b/icu4c/source/i18n/gregoimp.h
@@ -299,8 +299,8 @@ inline int32_t Grego::millisToJulianDay(double millis) {
 }
 
 inline int32_t Grego::gregorianShift(int32_t eyear) {
-  int32_t y = eyear-1;
-  int32_t gregShift = ClockMath::floorDivide(y, 400) - ClockMath::floorDivide(y, 100) + 2;
+  int64_t y = (int64_t)eyear-1;
+  int32_t gregShift = ClockMath::floorDivide(y, (int64_t)400) - ClockMath::floorDivide(y, (int64_t)100) + 2;
   return gregShift;
 }