From b2ca699076573c94fee9a73cb0d8645383b602a0 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 13 Feb 2013 17:53:28 +0100 Subject: [PATCH] USB: serial: fix null-pointer dereferences on disconnect Make sure serial-driver dtr_rts is called with disc_mutex held after checking the disconnected flag. Due to a bug in the tty layer, dtr_rts may get called after a device has been disconnected and the tty-device unregistered. Some drivers have had individual checks for disconnect to make sure the disconnected interface was not accessed, but this should really be handled in usb-serial core (at least until the long-standing tty-bug has been fixed). Note that the problem has been made more acute with commit 0998d0631001 ("device-core: Ensure drvdata = NULL when no driver is bound") as the port data is now also NULL when dtr_rts is called resulting in further oopses. Reported-by: Chris Ruehl Cc: stable Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 20 +++++++++----------- drivers/usb/serial/mct_u232.c | 22 +++++++++------------- drivers/usb/serial/quatech2.c | 18 ++++++++---------- drivers/usb/serial/sierra.c | 8 +------- drivers/usb/serial/ssu100.c | 19 ++++++++----------- drivers/usb/serial/usb-serial.c | 14 ++++++++++++-- drivers/usb/serial/usb_wwan.c | 8 +++----- 7 files changed, 50 insertions(+), 59 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 90ceef1776c3..d07fccf3bab5 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1886,24 +1886,22 @@ static void ftdi_dtr_rts(struct usb_serial_port *port, int on) { struct ftdi_private *priv = usb_get_serial_port_data(port); - mutex_lock(&port->serial->disc_mutex); - if (!port->serial->disconnected) { - /* Disable flow control */ - if (!on && usb_control_msg(port->serial->dev, + /* Disable flow control */ + if (!on) { + if (usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0), FTDI_SIO_SET_FLOW_CTRL_REQUEST, FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE, 0, priv->interface, NULL, 0, WDR_TIMEOUT) < 0) { - dev_err(&port->dev, "error from flowcontrol urb\n"); + dev_err(&port->dev, "error from flowcontrol urb\n"); } - /* drop RTS and DTR */ - if (on) - set_mctrl(port, TIOCM_DTR | TIOCM_RTS); - else - clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); } - mutex_unlock(&port->serial->disc_mutex); + /* drop RTS and DTR */ + if (on) + set_mctrl(port, TIOCM_DTR | TIOCM_RTS); + else + clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); } /* diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c index b6911757c855..d9c86516fed4 100644 --- a/drivers/usb/serial/mct_u232.c +++ b/drivers/usb/serial/mct_u232.c @@ -499,19 +499,15 @@ static void mct_u232_dtr_rts(struct usb_serial_port *port, int on) unsigned int control_state; struct mct_u232_private *priv = usb_get_serial_port_data(port); - mutex_lock(&port->serial->disc_mutex); - if (!port->serial->disconnected) { - /* drop DTR and RTS */ - spin_lock_irq(&priv->lock); - if (on) - priv->control_state |= TIOCM_DTR | TIOCM_RTS; - else - priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS); - control_state = priv->control_state; - spin_unlock_irq(&priv->lock); - mct_u232_set_modem_ctrl(port, control_state); - } - mutex_unlock(&port->serial->disc_mutex); + spin_lock_irq(&priv->lock); + if (on) + priv->control_state |= TIOCM_DTR | TIOCM_RTS; + else + priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS); + control_state = priv->control_state; + spin_unlock_irq(&priv->lock); + + mct_u232_set_modem_ctrl(port, control_state); } static void mct_u232_close(struct usb_serial_port *port) diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c index d152be97d041..a8d5110d4cc5 100644 --- a/drivers/usb/serial/quatech2.c +++ b/drivers/usb/serial/quatech2.c @@ -945,19 +945,17 @@ static void qt2_dtr_rts(struct usb_serial_port *port, int on) struct usb_device *dev = port->serial->dev; struct qt2_port_private *port_priv = usb_get_serial_port_data(port); - mutex_lock(&port->serial->disc_mutex); - if (!port->serial->disconnected) { - /* Disable flow control */ - if (!on && qt2_setregister(dev, port_priv->device_port, + /* Disable flow control */ + if (!on) { + if (qt2_setregister(dev, port_priv->device_port, UART_MCR, 0) < 0) dev_warn(&port->dev, "error from flowcontrol urb\n"); - /* drop RTS and DTR */ - if (on) - update_mctrl(port_priv, TIOCM_DTR | TIOCM_RTS, 0); - else - update_mctrl(port_priv, 0, TIOCM_DTR | TIOCM_RTS); } - mutex_unlock(&port->serial->disc_mutex); + /* drop RTS and DTR */ + if (on) + update_mctrl(port_priv, TIOCM_DTR | TIOCM_RTS, 0); + else + update_mctrl(port_priv, 0, TIOCM_DTR | TIOCM_RTS); } static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch) diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c index af06f2f5f38b..d4426c038c32 100644 --- a/drivers/usb/serial/sierra.c +++ b/drivers/usb/serial/sierra.c @@ -861,19 +861,13 @@ static int sierra_open(struct tty_struct *tty, struct usb_serial_port *port) static void sierra_dtr_rts(struct usb_serial_port *port, int on) { - struct usb_serial *serial = port->serial; struct sierra_port_private *portdata; portdata = usb_get_serial_port_data(port); portdata->rts_state = on; portdata->dtr_state = on; - if (serial->dev) { - mutex_lock(&serial->disc_mutex); - if (!serial->disconnected) - sierra_send_setup(port); - mutex_unlock(&serial->disc_mutex); - } + sierra_send_setup(port); } static int sierra_startup(struct usb_serial *serial) diff --git a/drivers/usb/serial/ssu100.c b/drivers/usb/serial/ssu100.c index 4543ea350229..d938396171e8 100644 --- a/drivers/usb/serial/ssu100.c +++ b/drivers/usb/serial/ssu100.c @@ -506,19 +506,16 @@ static void ssu100_dtr_rts(struct usb_serial_port *port, int on) { struct usb_device *dev = port->serial->dev; - mutex_lock(&port->serial->disc_mutex); - if (!port->serial->disconnected) { - /* Disable flow control */ - if (!on && - ssu100_setregister(dev, 0, UART_MCR, 0) < 0) + /* Disable flow control */ + if (!on) { + if (ssu100_setregister(dev, 0, UART_MCR, 0) < 0) dev_err(&port->dev, "error from flowcontrol urb\n"); - /* drop RTS and DTR */ - if (on) - set_mctrl(dev, TIOCM_DTR | TIOCM_RTS); - else - clear_mctrl(dev, TIOCM_DTR | TIOCM_RTS); } - mutex_unlock(&port->serial->disc_mutex); + /* drop RTS and DTR */ + if (on) + set_mctrl(dev, TIOCM_DTR | TIOCM_RTS); + else + clear_mctrl(dev, TIOCM_DTR | TIOCM_RTS); } static void ssu100_update_msr(struct usb_serial_port *port, u8 msr) diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 0a17f5942552..a19ed74d770d 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -694,10 +694,20 @@ static int serial_carrier_raised(struct tty_port *port) static void serial_dtr_rts(struct tty_port *port, int on) { struct usb_serial_port *p = container_of(port, struct usb_serial_port, port); - struct usb_serial_driver *drv = p->serial->type; + struct usb_serial *serial = p->serial; + struct usb_serial_driver *drv = serial->type; - if (drv->dtr_rts) + if (!drv->dtr_rts) + return; + /* + * Work-around bug in the tty-layer which can result in dtr_rts + * being called after a disconnect (and tty_unregister_device + * has returned). Remove once bug has been squashed. + */ + mutex_lock(&serial->disc_mutex); + if (!serial->disconnected) drv->dtr_rts(p, on); + mutex_unlock(&serial->disc_mutex); } static const struct tty_port_operations serial_port_ops = { diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c index 01c94aada56c..1355a6cd4508 100644 --- a/drivers/usb/serial/usb_wwan.c +++ b/drivers/usb/serial/usb_wwan.c @@ -38,7 +38,6 @@ void usb_wwan_dtr_rts(struct usb_serial_port *port, int on) { - struct usb_serial *serial = port->serial; struct usb_wwan_port_private *portdata; struct usb_wwan_intf_private *intfdata; @@ -48,12 +47,11 @@ void usb_wwan_dtr_rts(struct usb_serial_port *port, int on) return; portdata = usb_get_serial_port_data(port); - mutex_lock(&serial->disc_mutex); + /* FIXME: locking */ portdata->rts_state = on; portdata->dtr_state = on; - if (serial->dev) - intfdata->send_setup(port); - mutex_unlock(&serial->disc_mutex); + + intfdata->send_setup(port); } EXPORT_SYMBOL(usb_wwan_dtr_rts);