From: Yu Liao <liaoyu15@huawei.com> hulk inclusion category: bugfix bugzilla: 185831, https://gitee.com/openeuler/kernel/issues/I4MO2G CVE: NA ------------------------------------------------- Passing unnormalized timespec64 to timespec64_compare() may cause incorrect results. For example: wall_to_monotonic = {tv_sec = -10, tv_nsec = 900000000} ts_delta = {tv_sec = -9, tv_nsec = -900000000} timespec64_compare() returns -1, but actually wall_to_monotonic > ts_delta. This will cause wall_to_monotonic to become a positive number. Use timespec64_sub() instead of direct subtraction to avoid this. Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- include/linux/time64.h | 2 ++ kernel/time/timekeeping.c | 3 +-- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/time64.h b/include/linux/time64.h index b58142aa0b1dd..e58f59674ad6d 100644 --- a/include/linux/time64.h +++ b/include/linux/time64.h @@ -62,6 +62,8 @@ static inline int timespec64_equal(const struct timespec64 *a, * lhs < rhs: return <0 * lhs == rhs: return 0 * lhs > rhs: return >0 + * + * Note: Both lhs and rhs must be normalized. */ static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *rhs) { diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 64aa492f79422..17ba0a2f5f5d1 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1236,8 +1236,7 @@ int do_settimeofday64(const struct timespec64 *ts) timekeeping_forward_now(tk); xt = tk_xtime(tk); - ts_delta.tv_sec = ts->tv_sec - xt.tv_sec; - ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec; + ts_delta = timespec64_sub(*ts, xt); if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) { ret = -EINVAL; -- 2.25.1