Messages in this thread Patch in this message | | | From | ZhangXiaoxu <> | Subject | [PATCH] time: Validate the usec before covert to nsec in do_adjtimex | Date | Mon, 8 Jul 2019 15:55:04 +0800 |
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When covert the usec to nsec, it will multiple 1000, it maybe overflow and lead an undefined behavior.
For example, users may input an negative tv_usec values when call adjtimex syscall, then multiple 1000 maybe overflow it to a positive and legal number.
So, we should validate the usec before coverted it to nsec.
Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com> --- kernel/time/timekeeping.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 44b726b..e5c1d00 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1272,9 +1272,6 @@ static int timekeeping_inject_offset(const struct timespec64 *ts) struct timespec64 tmp; int ret = 0; - if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC) - return -EINVAL; - raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); @@ -2321,6 +2318,9 @@ int do_adjtimex(struct __kernel_timex *txc) if (txc->modes & ADJ_SETOFFSET) { struct timespec64 delta; + + if (txc->time.tv_usec < 0 || txc->time.tv_usec >= USEC_PER_SEC) + return -EINVAL; delta.tv_sec = txc->time.tv_sec; delta.tv_nsec = txc->time.tv_usec; if (!(txc->modes & ADJ_NANO)) -- 2.7.4
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