From 074b01a51d058f4216b7ce541e96b778aa6af60d Mon Sep 17 00:00:00 2001 From: ZhangXiaoxu Date: Thu, 20 Dec 2018 17:36:56 +0800 Subject: [PATCH] rtc: Fix UBSAN overflow warning Users may call 'ioctl' and pass a very big value on 'tm->tm_year'. It can be overflowed in 'int' after add 1900. In function 'rtc_month_days' and 'mktime64', also treated it as an 'unsigned' parameter. UBSAN: Undefined behaviour in drivers/rtc/rtc-lib.c:103:59 signed integer overflow: 2147483647 + 1900 cannot be represented in type 'int' UBSAN: Undefined behaviour in drivers/rtc/rtc-lib.c:119:30 signed integer overflow: 2147483647 + 1900 cannot be represented in type 'int' So, covert it to 'unsigned' explicitly. Signed-off-by: ZhangXiaoxu Signed-off-by: Alexandre Belloni --- drivers/rtc/lib.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/rtc/lib.c b/drivers/rtc/lib.c index ef160da84220..9714cb3d1e29 100644 --- a/drivers/rtc/lib.c +++ b/drivers/rtc/lib.c @@ -100,7 +100,7 @@ int rtc_valid_tm(struct rtc_time *tm) if (tm->tm_year < 70 || ((unsigned)tm->tm_mon) >= 12 || tm->tm_mday < 1 - || tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900) + || tm->tm_mday > rtc_month_days(tm->tm_mon, ((unsigned)tm->tm_year + 1900)) || ((unsigned)tm->tm_hour) >= 24 || ((unsigned)tm->tm_min) >= 60 || ((unsigned)tm->tm_sec) >= 60) @@ -116,8 +116,8 @@ EXPORT_SYMBOL(rtc_valid_tm); */ time64_t rtc_tm_to_time64(struct rtc_time *tm) { - return mktime64(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, - tm->tm_hour, tm->tm_min, tm->tm_sec); + return mktime64(((unsigned)tm->tm_year + 1900), tm->tm_mon + 1, + tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec); } EXPORT_SYMBOL(rtc_tm_to_time64);