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Subject[PATCH] time: Validate the usec before covert to nsec in do_adjtimex
Date
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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