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staging: exfat: stop using 32-bit time_t 

time_t suffers from overflow problems and should not be used.

In exfat, it is currently used in two open-coded time64_to_tm()
implementations. Changes those to use the existing function instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20190906150917.1025250-2-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
alistair/sunxi64-5.4-dsi
Arnd Bergmann 2019-09-06 17:09:05 +02:00 committed by Greg Kroah-Hartman
parent 26cf766091
commit 44f6b40c22
1 changed files with 38 additions and 126 deletions
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164
drivers/staging/exfat/exfat_super.c
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@ -53,129 +53,65 @@ static int exfat_write_inode(struct inode *inode,
static void exfat_write_super(struct super_block *sb);
#define UNIX_SECS_1980 315532800L
#if BITS_PER_LONG == 64
#define UNIX_SECS_2108 4354819200L
#endif
/* days between 1.1.70 and 1.1.80 (2 leap days) */
#define DAYS_DELTA_DECADE (365 * 10 + 2)
/* 120 (2100 - 1980) isn't leap year */
#define NO_LEAP_YEAR_2100 (120)
#define IS_LEAP_YEAR(y) (!((y) & 0x3) && (y) != NO_LEAP_YEAR_2100)
#define SECS_PER_MIN (60)
#define SECS_PER_HOUR (60 * SECS_PER_MIN)
#define SECS_PER_DAY (24 * SECS_PER_HOUR)
#define MAKE_LEAP_YEAR(leap_year, year) \
do { \
if (unlikely(year > NO_LEAP_YEAR_2100)) \
leap_year = ((year + 3) / 4) - 1; \
else \
leap_year = ((year + 3) / 4); \
} while (0)
/* Linear day numbers of the respective 1sts in non-leap years. */
static time_t accum_days_in_year[] = {
/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
};
/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
static void exfat_time_fat2unix(struct exfat_sb_info *sbi,
struct timespec64 *ts, struct date_time_t *tp)
{
time_t year = tp->Year;
time_t ld;
ts->tv_sec = mktime64(tp->Year + 1980, tp->Month + 1, tp->Day,
tp->Hour, tp->Minute, tp->Second);
MAKE_LEAP_YEAR(ld, year);
if (IS_LEAP_YEAR(year) && (tp->Month) > 2)
ld++;
ts->tv_sec = tp->Second +
tp->Minute * SECS_PER_MIN +
tp->Hour * SECS_PER_HOUR +
(ld + accum_days_in_year[(tp->Month)] +
(tp->Day - 1)) * SECS_PER_DAY +
(year * 365 + DAYS_DELTA_DECADE) * SECS_PER_DAY +
sys_tz.tz_minuteswest * SECS_PER_MIN;
ts->tv_nsec = 0;
ts->tv_nsec = tp->MilliSecond * NSEC_PER_MSEC;
}
/* Convert linear UNIX date to a FAT time/date pair. */
static void exfat_time_unix2fat(struct exfat_sb_info *sbi,
struct timespec64 *ts, struct date_time_t *tp)
{
time_t second = ts->tv_sec;
time_t day, month, year;
time_t ld;
time64_t second = ts->tv_sec;
struct tm tm;
second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
time64_to_tm(second, 0, &tm);
/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
if (second < UNIX_SECS_1980) {
tp->Second = 0;
tp->Minute = 0;
tp->Hour = 0;
tp->Day = 1;
tp->Month = 1;
tp->Year = 0;
tp->MilliSecond = 0;
tp->Second = 0;
tp->Minute = 0;
tp->Hour = 0;
tp->Day = 1;
tp->Month = 1;
tp->Year = 0;
return;
}
#if (BITS_PER_LONG == 64)
if (second >= UNIX_SECS_2108) {
tp->Second = 59;
tp->Minute = 59;
tp->Hour = 23;
tp->Day = 31;
tp->Month = 12;
tp->Year = 127;
tp->MilliSecond = 999;
tp->Second = 59;
tp->Minute = 59;
tp->Hour = 23;
tp->Day = 31;
tp->Month = 12;
tp->Year = 127;
return;
}
#endif
day = second / SECS_PER_DAY - DAYS_DELTA_DECADE;
year = day / 365;
MAKE_LEAP_YEAR(ld, year);
if (year * 365 + ld > day)
year--;
MAKE_LEAP_YEAR(ld, year);
day -= year * 365 + ld;
if (IS_LEAP_YEAR(year) && day == accum_days_in_year[3]) {
month = 2;
} else {
if (IS_LEAP_YEAR(year) && day > accum_days_in_year[3])
day--;
for (month = 1; month < 12; month++) {
if (accum_days_in_year[month + 1] > day)
break;
}
}
day -= accum_days_in_year[month];
tp->Second = second % SECS_PER_MIN;
tp->Minute = (second / SECS_PER_MIN) % 60;
tp->Hour = (second / SECS_PER_HOUR) % 24;
tp->Day = day + 1;
tp->Month = month;
tp->Year = year;
tp->MilliSecond = ts->tv_nsec / NSEC_PER_MSEC;
tp->Second = tm.tm_sec;
tp->Minute = tm.tm_min;
tp->Hour = tm.tm_hour;
tp->Day = tm.tm_mday;
tp->Month = tm.tm_mon + 1;
tp->Year = tm.tm_year + 1900 - 1980;
}
struct timestamp_t *tm_current(struct timestamp_t *tp)
{
struct timespec64 ts;
time_t second, day, leap_day, month, year;
time64_t second = ktime_get_real_seconds();
struct tm tm;
ktime_get_real_ts64(&ts);
time64_to_tm(second, 0, &tm);
second = ts.tv_sec;
second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
if (second < UNIX_SECS_1980) {
tp->sec = 0;
tp->min = 0;
@ -185,7 +121,7 @@ struct timestamp_t *tm_current(struct timestamp_t *tp)
tp->year = 0;
return tp;
}
#if BITS_PER_LONG == 64
if (second >= UNIX_SECS_2108) {
tp->sec = 59;
tp->min = 59;
@ -195,37 +131,13 @@ struct timestamp_t *tm_current(struct timestamp_t *tp)
tp->year = 127;
return tp;
}
#endif
day = second / SECS_PER_DAY - DAYS_DELTA_DECADE;
year = day / 365;
MAKE_LEAP_YEAR(leap_day, year);
if (year * 365 + leap_day > day)
year--;
MAKE_LEAP_YEAR(leap_day, year);
day -= year * 365 + leap_day;
if (IS_LEAP_YEAR(year) && day == accum_days_in_year[3]) {
month = 2;
} else {
if (IS_LEAP_YEAR(year) && day > accum_days_in_year[3])
day--;
for (month = 1; month < 12; month++) {
if (accum_days_in_year[month + 1] > day)
break;
}
}
day -= accum_days_in_year[month];
tp->sec = second % SECS_PER_MIN;
tp->min = (second / SECS_PER_MIN) % 60;
tp->hour = (second / SECS_PER_HOUR) % 24;
tp->day = day + 1;
tp->mon = month;
tp->year = year;
tp->sec = tm.tm_sec;
tp->min = tm.tm_min;
tp->hour = tm.tm_hour;
tp->day = tm.tm_mday;
tp->mon = tm.tm_mon + 1;
tp->year = tm.tm_year + 1900 - 1980;
return tp;
}