kernel-ark/include/linux/time.h
John Stultz 37cf4dc337 time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow
For adjtimex()'s ADJ_SETOFFSET, make sure the tv_usec value is
sane. We might multiply them later which can cause an overflow
and undefined behavior.

This patch introduces new helper functions to simplify the
checking code and adds comments to clarify

Orginally this patch was by Sasha Levin, but I've basically
rewritten it, so he should get credit for finding the issue
and I should get the blame for any mistakes made since.

Also, credit to Richard Cochran for the phrasing used in the
comment for what is considered valid here.

Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-10 22:41:06 -08:00

266 lines
7.3 KiB
C

#ifndef _LINUX_TIME_H
#define _LINUX_TIME_H
# include <linux/cache.h>
# include <linux/seqlock.h>
# include <linux/math64.h>
# include <linux/time64.h>
extern struct timezone sys_tz;
#define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
static inline int timespec_equal(const struct timespec *a,
const struct timespec *b)
{
return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
}
/*
* lhs < rhs: return <0
* lhs == rhs: return 0
* lhs > rhs: return >0
*/
static inline int timespec_compare(const struct timespec *lhs, const struct timespec *rhs)
{
if (lhs->tv_sec < rhs->tv_sec)
return -1;
if (lhs->tv_sec > rhs->tv_sec)
return 1;
return lhs->tv_nsec - rhs->tv_nsec;
}
static inline int timeval_compare(const struct timeval *lhs, const struct timeval *rhs)
{
if (lhs->tv_sec < rhs->tv_sec)
return -1;
if (lhs->tv_sec > rhs->tv_sec)
return 1;
return lhs->tv_usec - rhs->tv_usec;
}
extern time64_t mktime64(const unsigned int year, const unsigned int mon,
const unsigned int day, const unsigned int hour,
const unsigned int min, const unsigned int sec);
/**
* Deprecated. Use mktime64().
*/
static inline unsigned long mktime(const unsigned int year,
const unsigned int mon, const unsigned int day,
const unsigned int hour, const unsigned int min,
const unsigned int sec)
{
return mktime64(year, mon, day, hour, min, sec);
}
extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);
/*
* timespec_add_safe assumes both values are positive and checks
* for overflow. It will return TIME_T_MAX if the reutrn would be
* smaller then either of the arguments.
*/
extern struct timespec timespec_add_safe(const struct timespec lhs,
const struct timespec rhs);
static inline struct timespec timespec_add(struct timespec lhs,
struct timespec rhs)
{
struct timespec ts_delta;
set_normalized_timespec(&ts_delta, lhs.tv_sec + rhs.tv_sec,
lhs.tv_nsec + rhs.tv_nsec);
return ts_delta;
}
/*
* sub = lhs - rhs, in normalized form
*/
static inline struct timespec timespec_sub(struct timespec lhs,
struct timespec rhs)
{
struct timespec ts_delta;
set_normalized_timespec(&ts_delta, lhs.tv_sec - rhs.tv_sec,
lhs.tv_nsec - rhs.tv_nsec);
return ts_delta;
}
/*
* Returns true if the timespec is norm, false if denorm:
*/
static inline bool timespec_valid(const struct timespec *ts)
{
/* Dates before 1970 are bogus */
if (ts->tv_sec < 0)
return false;
/* Can't have more nanoseconds then a second */
if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
return false;
return true;
}
static inline bool timespec_valid_strict(const struct timespec *ts)
{
if (!timespec_valid(ts))
return false;
/* Disallow values that could overflow ktime_t */
if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
return false;
return true;
}
static inline bool timeval_valid(const struct timeval *tv)
{
/* Dates before 1970 are bogus */
if (tv->tv_sec < 0)
return false;
/* Can't have more microseconds then a second */
if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
return false;
return true;
}
extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
/*
* Validates if a timespec/timeval used to inject a time offset is valid.
* Offsets can be postive or negative. The value of the timeval/timespec
* is the sum of its fields, but *NOTE*: the field tv_usec/tv_nsec must
* always be non-negative.
*/
static inline bool timeval_inject_offset_valid(const struct timeval *tv)
{
/* We don't check the tv_sec as it can be positive or negative */
/* Can't have more microseconds then a second */
if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
return false;
return true;
}
static inline bool timespec_inject_offset_valid(const struct timespec *ts)
{
/* We don't check the tv_sec as it can be positive or negative */
/* Can't have more nanoseconds then a second */
if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
return false;
return true;
}
#define CURRENT_TIME (current_kernel_time())
#define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 })
/* Some architectures do not supply their own clocksource.
* This is mainly the case in architectures that get their
* inter-tick times by reading the counter on their interval
* timer. Since these timers wrap every tick, they're not really
* useful as clocksources. Wrapping them to act like one is possible
* but not very efficient. So we provide a callout these arches
* can implement for use with the jiffies clocksource to provide
* finer then tick granular time.
*/
#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
extern u32 (*arch_gettimeoffset)(void);
#endif
struct itimerval;
extern int do_setitimer(int which, struct itimerval *value,
struct itimerval *ovalue);
extern int do_getitimer(int which, struct itimerval *value);
extern unsigned int alarm_setitimer(unsigned int seconds);
extern long do_utimes(int dfd, const char __user *filename, struct timespec *times, int flags);
struct tms;
extern void do_sys_times(struct tms *);
/*
* Similar to the struct tm in userspace <time.h>, but it needs to be here so
* that the kernel source is self contained.
*/
struct tm {
/*
* the number of seconds after the minute, normally in the range
* 0 to 59, but can be up to 60 to allow for leap seconds
*/
int tm_sec;
/* the number of minutes after the hour, in the range 0 to 59*/
int tm_min;
/* the number of hours past midnight, in the range 0 to 23 */
int tm_hour;
/* the day of the month, in the range 1 to 31 */
int tm_mday;
/* the number of months since January, in the range 0 to 11 */
int tm_mon;
/* the number of years since 1900 */
long tm_year;
/* the number of days since Sunday, in the range 0 to 6 */
int tm_wday;
/* the number of days since January 1, in the range 0 to 365 */
int tm_yday;
};
void time_to_tm(time_t totalsecs, int offset, struct tm *result);
/**
* timespec_to_ns - Convert timespec to nanoseconds
* @ts: pointer to the timespec variable to be converted
*
* Returns the scalar nanosecond representation of the timespec
* parameter.
*/
static inline s64 timespec_to_ns(const struct timespec *ts)
{
return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
}
/**
* timeval_to_ns - Convert timeval to nanoseconds
* @ts: pointer to the timeval variable to be converted
*
* Returns the scalar nanosecond representation of the timeval
* parameter.
*/
static inline s64 timeval_to_ns(const struct timeval *tv)
{
return ((s64) tv->tv_sec * NSEC_PER_SEC) +
tv->tv_usec * NSEC_PER_USEC;
}
/**
* ns_to_timespec - Convert nanoseconds to timespec
* @nsec: the nanoseconds value to be converted
*
* Returns the timespec representation of the nsec parameter.
*/
extern struct timespec ns_to_timespec(const s64 nsec);
/**
* ns_to_timeval - Convert nanoseconds to timeval
* @nsec: the nanoseconds value to be converted
*
* Returns the timeval representation of the nsec parameter.
*/
extern struct timeval ns_to_timeval(const s64 nsec);
/**
* timespec_add_ns - Adds nanoseconds to a timespec
* @a: pointer to timespec to be incremented
* @ns: unsigned nanoseconds value to be added
*
* This must always be inlined because its used from the x86-64 vdso,
* which cannot call other kernel functions.
*/
static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
{
a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
a->tv_nsec = ns;
}
#endif