Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.
Use sysfs_lock to protect sysfs paths in vudc.
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/usbip/vudc_dev.c | 1 +
drivers/usb/usbip/vudc_sysfs.c | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c
index c8eeabdd9b56..2bc428f2e261 100644
--- a/drivers/usb/usbip/vudc_dev.c
+++ b/drivers/usb/usbip/vudc_dev.c
@@ -572,6 +572,7 @@ static int init_vudc_hw(struct vudc *udc)
init_waitqueue_head(&udc->tx_waitq);
spin_lock_init(&ud->lock);
+ mutex_init(&ud->sysfs_lock);
ud->status = SDEV_ST_AVAILABLE;
ud->side = USBIP_VUDC;
diff --git a/drivers/usb/usbip/vudc_sysfs.c b/drivers/usb/usbip/vudc_sysfs.c
index 7383a543c6d1..f7633ee655a1 100644
--- a/drivers/usb/usbip/vudc_sysfs.c
+++ b/drivers/usb/usbip/vudc_sysfs.c
@@ -112,6 +112,7 @@ static ssize_t usbip_sockfd_store(struct device *dev,
dev_err(dev, "no device");
return -ENODEV;
}
+ mutex_lock(&udc->ud.sysfs_lock);
spin_lock_irqsave(&udc->lock, flags);
/* Don't export what we don't have */
if (!udc->driver || !udc->pullup) {
@@ -187,6 +188,8 @@ static ssize_t usbip_sockfd_store(struct device *dev,
wake_up_process(udc->ud.tcp_rx);
wake_up_process(udc->ud.tcp_tx);
+
+ mutex_unlock(&udc->ud.sysfs_lock);
return count;
} else {
@@ -207,6 +210,7 @@ static ssize_t usbip_sockfd_store(struct device *dev,
}
spin_unlock_irqrestore(&udc->lock, flags);
+ mutex_unlock(&udc->ud.sysfs_lock);
return count;
@@ -216,6 +220,7 @@ static ssize_t usbip_sockfd_store(struct device *dev,
spin_unlock_irq(&udc->ud.lock);
unlock:
spin_unlock_irqrestore(&udc->lock, flags);
+ mutex_unlock(&udc->ud.sysfs_lock);
return ret;
}
--
2.27.0
