From c75b811de0afeea6acf19c99a755b8e1c0585aa9 Mon Sep 17 00:00:00 2001 From: Nick Wellnhofer Date: Thu, 25 Apr 2019 11:16:58 +0200 Subject: [PATCH 12/26] Fix integer overflow in _exsltDateDayInWeek Found by OSS-Fuzz. --- libexslt/date.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/libexslt/date.c b/libexslt/date.c index 32c9db7..d075adc 100644 --- a/libexslt/date.c +++ b/libexslt/date.c @@ -1474,11 +1474,12 @@ _exsltDateDayInWeek(long yday, long yr) long ret; if (yr <= 0) { - ret = ((yr-2 + ((yr/4)-(yr/100)+(yr/400)) + yday) % 7); + /* Compute modulus twice to avoid integer overflow */ + ret = ((yr%7-2 + ((yr/4)-(yr/100)+(yr/400)) + yday) % 7); if (ret < 0) ret += 7; } else - ret = (((yr-1) + (((yr-1)/4)-((yr-1)/100)+((yr-1)/400)) + yday) % 7); + ret = (((yr%7-1) + (((yr-1)/4)-((yr-1)/100)+((yr-1)/400)) + yday) % 7); return ret; } -- 1.8.3.1