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authorShuah Khan <skhan@linuxfoundation.org>2021-03-29 19:36:50 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-04-05 09:05:42 +0200
commitbd8b82042269a95db48074b8bb400678dbac1815 (patch)
tree43af66f344afc0a2222eaad8cf7b1b99642e3f9b /drivers/usb/usbip
parent9dbf34a834563dada91366c2ac266f32ff34641a (diff)
downloadlinux-bd8b82042269a95db48074b8bb400678dbac1815.tar.gz
usbip: vudc synchronize sysfs code paths
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.

Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/caabcf3fc87bdae970509b5ff32d05bb7ce2fb15.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/usbip')
-rw-r--r--drivers/usb/usbip/vudc_dev.c1
-rw-r--r--drivers/usb/usbip/vudc_sysfs.c5
2 files changed, 6 insertions, 0 deletions
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 @@ unlock_ud:
 	spin_unlock_irq(&udc->ud.lock);
 unlock:
 	spin_unlock_irqrestore(&udc->lock, flags);
+	mutex_unlock(&udc->ud.sysfs_lock);
 
 	return ret;
 }