[PATCH net] ptp: Return -EINVAL on ptp_clock_register if required ops are NULL

[Tim Hostetler <thostet@google.com>]

ptp_clock should never be registered unless it stubs one of gettimex64()
or gettime64() and settime64(). WARN_ON_ONCE and error out if either set
of function pointers is null.

Cc: stable@vger.kernel.org
Fixes: d7d38f5bd7be ("ptp: use the 64 bit get/set time methods for the posix clock.")
Suggested-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: Tim Hostetler <thostet@google.com>
---
 drivers/ptp/ptp_clock.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index ef020599b771..0bc79076771b 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -325,6 +325,10 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	if (info->n_alarm > PTP_MAX_ALARMS)
 		return ERR_PTR(-EINVAL);
 
+	if (WARN_ON_ONCE((!info->gettimex64 && !info->gettime64) ||
+			 !info->settime64))
+		return ERR_PTR(-EINVAL);
+
 	/* Initialize a clock structure. */
 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
 	if (!ptp) {
-- 
2.51.1.851.g4ebd6896fd-goog