[PATCH] platform/chrome: cros_ec_typec: zero out stale pointers

[Victor Ding]

`cros_typec_get_switch_handles` allocates several pointers when
obtaining four handles. These pointers are all freed if failing to
obtain any of the four handles; therefore, pointers in `port` becomes
stale. The stale pointers eventually cause use-after-free or double in
later code paths.

This patch proposes to elimite these stale pointers by zeroing them out
right after they are freed.

Signed-off-by: Victor Ding <victording@xxxxxxxxxxxx>
---

 drivers/platform/chrome/cros_ec_typec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 2a7ff14dc37e..59de4ce01fab 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -173,10 +173,13 @@ static int cros_typec_get_switch_handles(struct cros_typec_port *port,
 
 role_sw_err:
 	typec_switch_put(port->ori_sw);
+	port->ori_sw = NULL;
 ori_sw_err:
 	typec_retimer_put(port->retimer);
+	port->retimer = NULL;
 retimer_sw_err:
 	typec_mux_put(port->mux);
+	port->mux = NULL;
 mux_err:
 	return -ENODEV;
 }
-- 
2.39.0.rc0.267.gcb52ba06e7-goog