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usbip: stub-dev 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 stub-dev.

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/2b182f3561b4a065bf3bf6dce3b0e9944ba17b3f.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shuah Khan 2021-03-29 19:36:49 -06:00 committed by Greg Kroah-Hartman
parent 4e9c93af72
commit 9dbf34a834
1 changed files with 9 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/usb/usbip/stub_dev.c
View File

@ -63,6 +63,7 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a
dev_info(dev, "stub up\n");
mutex_lock(&sdev->ud.sysfs_lock);
spin_lock_irq(&sdev->ud.lock);
if (sdev->ud.status != SDEV_ST_AVAILABLE) {
@ -87,13 +88,13 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a
tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx");
if (IS_ERR(tcp_rx)) {
sockfd_put(socket);
return -EINVAL;
goto unlock_mutex;
}
tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx");
if (IS_ERR(tcp_tx)) {
kthread_stop(tcp_rx);
sockfd_put(socket);
return -EINVAL;
goto unlock_mutex;
}
/* get task structs now */
@ -112,6 +113,8 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a
wake_up_process(sdev->ud.tcp_rx);
wake_up_process(sdev->ud.tcp_tx);
mutex_unlock(&sdev->ud.sysfs_lock);
} else {
dev_info(dev, "stub down\n");
@ -122,6 +125,7 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a
spin_unlock_irq(&sdev->ud.lock);
usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
mutex_unlock(&sdev->ud.sysfs_lock);
}
return count;
@ -130,6 +134,8 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a
sockfd_put(socket);
err:
spin_unlock_irq(&sdev->ud.lock);
unlock_mutex:
mutex_unlock(&sdev->ud.sysfs_lock);
return -EINVAL;
}
static DEVICE_ATTR_WO(usbip_sockfd);
@ -270,6 +276,7 @@ static struct stub_device *stub_device_alloc(struct usb_device *udev)
sdev->ud.side = USBIP_STUB;
sdev->ud.status = SDEV_ST_AVAILABLE;
spin_lock_init(&sdev->ud.lock);
mutex_init(&sdev->ud.sysfs_lock);
sdev->ud.tcp_socket = NULL;
sdev->ud.sockfd = -1;