From 430d57f53eb1cdbf9ba9bbd397317912b3cd2de5 Mon Sep 17 00:00:00 2001 From: Ray Chi Date: Mon, 7 Nov 2022 15:27:54 +0800 Subject: usb: core: stop USB enumeration if too many retries When a broken USB accessory connects to a USB host, usbcore might keep doing enumeration retries. If the host has a watchdog mechanism, the kernel panic will happen on the host. This patch provides an attribute early_stop to limit the numbers of retries for each port of a hub. If a port was marked with early_stop attribute, unsuccessful connection attempts will fail quickly. In addition, if an early_stop port has failed to initialize, it will ignore all future connection events until early_stop attribute is clear. Signed-off-by: Ray Chi Reviewed-by: Alan Stern Link: https://lore.kernel.org/r/20221107072754.3336357-1-raychi@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'drivers/usb/core/hub.c') diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index bbab424b0d55..77e73fc8d673 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -3081,6 +3081,48 @@ done: return status; } +/* + * hub_port_stop_enumerate - stop USB enumeration or ignore port events + * @hub: target hub + * @port1: port num of the port + * @retries: port retries number of hub_port_init() + * + * Return: + * true: ignore port actions/events or give up connection attempts. + * false: keep original behavior. + * + * This function will be based on retries to check whether the port which is + * marked with early_stop attribute would stop enumeration or ignore events. + * + * Note: + * This function didn't change anything if early_stop is not set, and it will + * prevent all connection attempts when early_stop is set and the attempts of + * the port are more than 1. + */ +static bool hub_port_stop_enumerate(struct usb_hub *hub, int port1, int retries) +{ + struct usb_port *port_dev = hub->ports[port1 - 1]; + + if (port_dev->early_stop) { + if (port_dev->ignore_event) + return true; + + /* + * We want unsuccessful attempts to fail quickly. + * Since some devices may need one failure during + * port initialization, we allow two tries but no + * more. + */ + if (retries < 2) + return false; + + port_dev->ignore_event = 1; + } else + port_dev->ignore_event = 0; + + return port_dev->ignore_event; +} + /* Check if a port is power on */ int usb_port_is_power_on(struct usb_hub *hub, unsigned int portstatus) { @@ -4796,6 +4838,11 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, do_new_scheme = use_new_scheme(udev, retry_counter, port_dev); for (retries = 0; retries < GET_DESCRIPTOR_TRIES; (++retries, msleep(100))) { + if (hub_port_stop_enumerate(hub, port1, retries)) { + retval = -ENODEV; + break; + } + if (do_new_scheme) { struct usb_device_descriptor *buf; int r = 0; @@ -5246,6 +5293,11 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, status = 0; for (i = 0; i < PORT_INIT_TRIES; i++) { + if (hub_port_stop_enumerate(hub, port1, i)) { + status = -ENODEV; + break; + } + usb_lock_port(port_dev); mutex_lock(hcd->address0_mutex); retry_locked = true; @@ -5614,6 +5666,10 @@ static void port_event(struct usb_hub *hub, int port1) if (!pm_runtime_active(&port_dev->dev)) return; + /* skip port actions if ignore_event and early_stop are true */ + if (port_dev->ignore_event && port_dev->early_stop) + return; + if (hub_handle_remote_wakeup(hub, port1, portstatus, portchange)) connect_change = 1; @@ -5927,6 +5983,10 @@ static int usb_reset_and_verify_device(struct usb_device *udev) mutex_lock(hcd->address0_mutex); for (i = 0; i < PORT_INIT_TRIES; ++i) { + if (hub_port_stop_enumerate(parent_hub, port1, i)) { + ret = -ENODEV; + break; + } /* ep0 maxpacket size may change; let the HCD know about it. * Other endpoints will be handled by re-enumeration. */ -- cgit