[PATCH -next v4 1/2] posix-clock: Check timespec64 before call clock_settime()

[Jinjie Ruan]

As Andrew pointed out, it will make sense that the PTP core
checked timespec64 struct's tv_sec and tv_nsec range before calling
ptp->info->settime64().

As the man mannul of clock_settime() said, if tp.tv_sec is negative or
tp.tv_nsec is outside the range [0..999,999,999], it shuld return EINVAL,
which include Dynamic clocks which handles PTP clock, and the condition is
consistent with timespec64_valid(). So check it ahead using
timespec64_valid() in pc_clock_settime() and return -EINVAL if not valid.

There are some drivers that use tp->tv_sec and tp->tv_nsec directly to
write registers without validity checks and assume that the higher layer
has checked it, which is dangerous and will benefit from this, such as
hclge_ptp_settime(), igb_ptp_settime_i210(), _rcar_gen4_ptp_settime(),
and some drivers can remove the checks of itself.

Suggested-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
v4:
- Check it in pc_clock_settime().
- Update the commit message.
v3:
- Adjust to check in more higher layer clock_settime().
- Remove the NULL check.
- Update the commit message and subject.
v2:
- Adjust to check in ptp_clock_settime().
---
 kernel/time/posix-clock.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 4782edcbe7b9..89e39f9bd7ae 100644
--- a/kernel/time/posix-clock.c
+++ b/kernel/time/posix-clock.c
@@ -319,6 +319,9 @@ static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
 		goto out;
 	}
 
+	if (!timespec64_valid(ts))
+		return -EINVAL;
+
 	if (cd.clk->ops.clock_settime)
 		err = cd.clk->ops.clock_settime(cd.clk, ts);
 	else
-- 
2.34.1