usb: typec: class: Fix NULL pointer access

Concurrent calls to typec_partner_unlink_device can lead to a NULL pointer
dereference. This patch adds a mutex to protect USB device pointers and
prevent this issue. The same mutex protects both the device pointers and
the partner device registration.

Cc: stable@vger.kernel.org
Fixes: 59de2a56d127 ("usb: typec: Link enumerated USB devices with Type-C partner")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20250321143728.4092417-2-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 9c76c3d0c6cff9c9b94ef35fb0cb4be0e395aad6..eadb150223f8f86daf12d87ad9f180bc8af9e0c1 100644 (file)
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -1052,6 +1052,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
                partner->usb_mode = USB_MODE_USB3;
        }
 
+       mutex_lock(&port->partner_link_lock);
        ret = device_register(&partner->dev);
        if (ret) {
                dev_err(&port->dev, "failed to register partner (%d)\n", ret);
@@ -1063,6 +1064,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
                typec_partner_link_device(partner, port->usb2_dev);
        if (port->usb3_dev)
                typec_partner_link_device(partner, port->usb3_dev);
+       mutex_unlock(&port->partner_link_lock);
 
        return partner;
 }
@@ -1083,12 +1085,14 @@ void typec_unregister_partner(struct typec_partner *partner)
 
        port = to_typec_port(partner->dev.parent);
 
+       mutex_lock(&port->partner_link_lock);
        if (port->usb2_dev)
                typec_partner_unlink_device(partner, port->usb2_dev);
        if (port->usb3_dev)
                typec_partner_unlink_device(partner, port->usb3_dev);
 
        device_unregister(&partner->dev);
+       mutex_unlock(&port->partner_link_lock);
 }
 EXPORT_SYMBOL_GPL(typec_unregister_partner);
 
@@ -2041,10 +2045,11 @@ static struct typec_partner *typec_get_partner(struct typec_port *port)
 static void typec_partner_attach(struct typec_connector *con, struct device *dev)
 {
        struct typec_port *port = container_of(con, struct typec_port, con);
-       struct typec_partner *partner = typec_get_partner(port);
+       struct typec_partner *partner;
        struct usb_device *udev = to_usb_device(dev);
        enum usb_mode usb_mode;
 
+       mutex_lock(&port->partner_link_lock);
        if (udev->speed < USB_SPEED_SUPER) {
                usb_mode = USB_MODE_USB2;
                port->usb2_dev = dev;
@@ -2053,18 +2058,22 @@ static void typec_partner_attach(struct typec_connector *con, struct device *dev
                port->usb3_dev = dev;
        }
 
+       partner = typec_get_partner(port);
        if (partner) {
                typec_partner_set_usb_mode(partner, usb_mode);
                typec_partner_link_device(partner, dev);
                put_device(&partner->dev);
        }
+       mutex_unlock(&port->partner_link_lock);
 }
 
 static void typec_partner_deattach(struct typec_connector *con, struct device *dev)
 {
        struct typec_port *port = container_of(con, struct typec_port, con);
-       struct typec_partner *partner = typec_get_partner(port);
+       struct typec_partner *partner;
 
+       mutex_lock(&port->partner_link_lock);
+       partner = typec_get_partner(port);
        if (partner) {
                typec_partner_unlink_device(partner, dev);
                put_device(&partner->dev);
@@ -2074,6 +2083,7 @@ static void typec_partner_deattach(struct typec_connector *con, struct device *d
                port->usb2_dev = NULL;
        else if (port->usb3_dev == dev)
                port->usb3_dev = NULL;
+       mutex_unlock(&port->partner_link_lock);
 }
 
 /**
@@ -2614,6 +2624,7 @@ struct typec_port *typec_register_port(struct device *parent,
 
        ida_init(&port->mode_ids);
        mutex_init(&port->port_type_lock);
+       mutex_init(&port->partner_link_lock);
 
        port->id = id;
        port->ops = cap->ops;

diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index b3076a24ad2eeef3fc04bebe47c2636306e96f18..db2fe96c48ff0fb7ad70151e41353978b2383b7b 100644 (file)
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -59,6 +59,7 @@ struct typec_port {
        enum typec_port_type            port_type;
        enum usb_mode                   usb_mode;
        struct mutex                    port_type_lock;
+       struct mutex                    partner_link_lock;
 
        enum typec_orientation          orientation;
        struct typec_switch             *sw;