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![Zeng Tao](/assets/img/avatar_default.png)
UBSAN reports: Undefined behaviour in ./include/linux/time64.h:127:27 signed integer overflow: 17179869187 * 1000000000 cannot be represented in type 'long long int' Call Trace: timespec64_to_ns include/linux/time64.h:127 [inline] set_cpu_itimer+0x65c/0x880 kernel/time/itimer.c:180 do_setitimer+0x8e/0x740 kernel/time/itimer.c:245 __x64_sys_setitimer+0x14c/0x2c0 kernel/time/itimer.c:336 do_syscall_64+0xa1/0x540 arch/x86/entry/common.c:295 Commitbd40a17576
("y2038: itimer: change implementation to timespec64") replaced the original conversion which handled time clamping correctly with timespec64_to_ns() which has no overflow protection. Fix it in timespec64_to_ns() as this is not necessarily limited to the usage in itimers. [ tglx: Added comment and adjusted the fixes tag ] Fixes:361a3bf005
("time64: Add time64.h header and define struct timespec64") Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1598952616-6416-1-git-send-email-prime.zeng@hisilicon.com
163 lines
4.4 KiB
C
163 lines
4.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_TIME64_H
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#define _LINUX_TIME64_H
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#include <linux/math64.h>
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#include <vdso/time64.h>
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typedef __s64 time64_t;
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typedef __u64 timeu64_t;
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#include <uapi/linux/time.h>
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struct timespec64 {
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time64_t tv_sec; /* seconds */
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long tv_nsec; /* nanoseconds */
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};
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struct itimerspec64 {
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struct timespec64 it_interval;
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struct timespec64 it_value;
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};
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/* Located here for timespec[64]_valid_strict */
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#define TIME64_MAX ((s64)~((u64)1 << 63))
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#define TIME64_MIN (-TIME64_MAX - 1)
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#define KTIME_MAX ((s64)~((u64)1 << 63))
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#define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC)
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/*
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* Limits for settimeofday():
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*
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* To prevent setting the time close to the wraparound point time setting
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* is limited so a reasonable uptime can be accomodated. Uptime of 30 years
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* should be really sufficient, which means the cutoff is 2232. At that
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* point the cutoff is just a small part of the larger problem.
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*/
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#define TIME_UPTIME_SEC_MAX (30LL * 365 * 24 *3600)
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#define TIME_SETTOD_SEC_MAX (KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
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static inline int timespec64_equal(const struct timespec64 *a,
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const struct timespec64 *b)
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{
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return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
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}
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/*
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* lhs < rhs: return <0
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* lhs == rhs: return 0
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* lhs > rhs: return >0
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*/
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static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs)
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{
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if (lhs->tv_sec < rhs->tv_sec)
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return -1;
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if (lhs->tv_sec > rhs->tv_sec)
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return 1;
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return lhs->tv_nsec - rhs->tv_nsec;
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}
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extern void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);
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static inline struct timespec64 timespec64_add(struct timespec64 lhs,
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struct timespec64 rhs)
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{
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struct timespec64 ts_delta;
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set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
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lhs.tv_nsec + rhs.tv_nsec);
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return ts_delta;
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}
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/*
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* sub = lhs - rhs, in normalized form
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*/
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static inline struct timespec64 timespec64_sub(struct timespec64 lhs,
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struct timespec64 rhs)
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{
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struct timespec64 ts_delta;
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set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
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lhs.tv_nsec - rhs.tv_nsec);
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return ts_delta;
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}
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/*
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* Returns true if the timespec64 is norm, false if denorm:
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*/
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static inline bool timespec64_valid(const struct timespec64 *ts)
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{
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/* Dates before 1970 are bogus */
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if (ts->tv_sec < 0)
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return false;
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/* Can't have more nanoseconds then a second */
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if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
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return false;
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return true;
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}
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static inline bool timespec64_valid_strict(const struct timespec64 *ts)
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{
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if (!timespec64_valid(ts))
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return false;
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/* Disallow values that could overflow ktime_t */
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if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
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return false;
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return true;
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}
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static inline bool timespec64_valid_settod(const struct timespec64 *ts)
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{
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if (!timespec64_valid(ts))
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return false;
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/* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
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if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
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return false;
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return true;
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}
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/**
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* timespec64_to_ns - Convert timespec64 to nanoseconds
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* @ts: pointer to the timespec64 variable to be converted
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*
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* Returns the scalar nanosecond representation of the timespec64
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* parameter.
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*/
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static inline s64 timespec64_to_ns(const struct timespec64 *ts)
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{
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/* Prevent multiplication overflow */
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if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
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return KTIME_MAX;
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return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
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}
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/**
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* ns_to_timespec64 - Convert nanoseconds to timespec64
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* @nsec: the nanoseconds value to be converted
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*
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* Returns the timespec64 representation of the nsec parameter.
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*/
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extern struct timespec64 ns_to_timespec64(const s64 nsec);
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/**
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* timespec64_add_ns - Adds nanoseconds to a timespec64
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* @a: pointer to timespec64 to be incremented
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* @ns: unsigned nanoseconds value to be added
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*
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* This must always be inlined because its used from the x86-64 vdso,
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* which cannot call other kernel functions.
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*/
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static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
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{
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a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
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a->tv_nsec = ns;
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}
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/*
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* timespec64_add_safe assumes both values are positive and checks for
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* overflow. It will return TIME64_MAX in case of overflow.
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*/
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extern struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
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const struct timespec64 rhs);
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#endif /* _LINUX_TIME64_H */
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