linux-stable/fs/udf/udftime.c
Roman Smirnov 3b84adf460 udf: udftime: prevent overflow in udf_disk_stamp_to_time()
An overflow can occur in a situation where src.centiseconds
takes the value of 255. This situation is unlikely, but there
is no validation check anywere in the code.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240327132755.13945-1-r.smirnov@omp.ru>
2024-04-10 13:10:12 +02:00

90 lines
2.6 KiB
C

// SPDX-License-Identifier: LGPL-2.0+
/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Eggert (eggert@twinsun.com). */
/*
* dgb 10/02/98: ripped this from glibc source to help convert timestamps
* to unix time
* 10/04/98: added new table-based lookup after seeing how ugly
* the gnu code is
* blf 09/27/99: ripped out all the old code and inserted new table from
* John Brockmeyer (without leap second corrections)
* rewrote udf_stamp_to_time and fixed timezone accounting in
* udf_time_to_stamp.
*/
/*
* We don't take into account leap seconds. This may be correct or incorrect.
* For more NIST information (especially dealing with leap seconds), see:
* http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
*/
#include "udfdecl.h"
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/time.h>
void
udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src)
{
u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
u16 year = le16_to_cpu(src.year);
uint8_t type = typeAndTimezone >> 12;
int16_t offset;
if (type == 1) {
offset = typeAndTimezone << 4;
/* sign extent offset */
offset = (offset >> 4);
if (offset == -2047) /* unspecified offset */
offset = 0;
} else
offset = 0;
dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
src.second);
dest->tv_sec -= offset * 60;
/*
* Sanitize nanosecond field since reportedly some filesystems are
* recorded with bogus sub-second values.
*/
if (src.centiseconds < 100 && src.hundredsOfMicroseconds < 100 &&
src.microseconds < 100) {
dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
src.hundredsOfMicroseconds * 100 + src.microseconds);
} else {
dest->tv_nsec = 0;
}
}
void
udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts)
{
time64_t seconds;
int16_t offset;
struct tm tm;
offset = -sys_tz.tz_minuteswest;
dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
seconds = ts.tv_sec + offset * 60;
time64_to_tm(seconds, 0, &tm);
dest->year = cpu_to_le16(tm.tm_year + 1900);
dest->month = tm.tm_mon + 1;
dest->day = tm.tm_mday;
dest->hour = tm.tm_hour;
dest->minute = tm.tm_min;
dest->second = tm.tm_sec;
dest->centiseconds = ts.tv_nsec / 10000000;
dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
dest->centiseconds * 10000) / 100;
dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
dest->hundredsOfMicroseconds * 100);
}
/* EOF */