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usbip: vudc synchronize sysfs code paths

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commit bd8b82042269a95db48074b8bb400678dbac1815 upstream.

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 # 4.9.x # 4.14.x
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: Tom Seewald <tseewald@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shuah Khan 2021-04-16 15:53:18 -05:00 committed by Greg Kroah-Hartman
parent f7df446815
commit 94b9c4c583
2 changed files with 6 additions and 0 deletions
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1
drivers/usb/usbip/vudc_dev.c
View File

@ -582,6 +582,7 @@ 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;

5
drivers/usb/usbip/vudc_sysfs.c
View File

@ -125,6 +125,7 @@ static ssize_t store_sockfd(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) {
@ -200,6 +201,8 @@ static ssize_t store_sockfd(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 {
@ -220,6 +223,7 @@ static ssize_t store_sockfd(struct device *dev,
}
spin_unlock_irqrestore(&udc->lock, flags);
mutex_unlock(&udc->ud.sysfs_lock);
return count;
@ -229,6 +233,7 @@ unlock_ud:
spin_unlock_irq(&udc->ud.lock);
unlock:
spin_unlock_irqrestore(&udc->lock, flags);
mutex_unlock(&udc->ud.sysfs_lock);
return ret;
}