ptp: Ensure info->enable callback is always set
commit fd53aa40e65f518453115b6f56183b0c201db26b upstream.
The ioctl and sysfs handlers unconditionally call the ->enable callback.
Not all drivers implement that callback, leading to NULL dereferences.
Example of affected drivers: ptp_s390.c, ptp_vclock.c and ptp_mock.c.
Instead use a dummy callback if no better was specified by the driver.
BUG=b/401203900
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2025-21814 in the Linux kernel.
cos-patch: security-moderate
Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
Cc: stable@vger.kernel.org
Change-Id: I5087b23f08a478e28d9569887028d172102815fe
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://patch.msgid.link/20250123-ptp-enable-v1-1-b015834d3a47@weissschuh.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/95259
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Kevin Berry <kpberry@google.com>
Reviewed-by: Arnav Kansal <rnv@google.com>
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 389599b..af66ed4 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -188,6 +188,11 @@ static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
return info->gettime64(info, ts);
}
+static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
+{
+ return -EOPNOTSUPP;
+}
+
static void ptp_aux_kworker(struct kthread_work *work)
{
struct ptp_clock *ptp = container_of(work, struct ptp_clock,
@@ -250,6 +255,9 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
ptp->info->getcrosscycles = ptp->info->getcrosststamp;
}
+ if (!ptp->info->enable)
+ ptp->info->enable = ptp_enable;
+
if (ptp->info->do_aux_work) {
kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
