usbip_sockfd_store() must perform
if (udc->ud.status != SDEV_ST_AVAILABLE) {
/* misc assignments for attach operation */
udc->ud.status = SDEV_ST_USED;
}
under a lock, or multiple ud->tcp_{tx,rx} are created (which will later
cause a crash like [1]) and refcount on ud->tcp_socket is leaked when
usbip_sockfd_store() is concurrently called.
Since I don't want to replace "return" with "goto" in order to call
usbip_event_unlock(), wrap whole function in order to keep changes
minimal.
[1] https://syzkaller.appspot.com/bug?extid=95ce4b142579611ef0a9
Reported-by: syzbot <syzbot+95ce4b142579611ef0a9@xxxxxxxxxxxxxxxxxxxxxxxxx>
Tested-by: syzbot <syzbot+a93fba6d384346a761e3@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/usbip/vudc_sysfs.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/usbip/vudc_sysfs.c b/drivers/usb/usbip/vudc_sysfs.c
index 100f680c572a..ebf6a127fcc3 100644
--- a/drivers/usb/usbip/vudc_sysfs.c
+++ b/drivers/usb/usbip/vudc_sysfs.c
@@ -90,8 +90,8 @@ static ssize_t dev_desc_read(struct file *file, struct kobject *kobj,
}
static BIN_ATTR_RO(dev_desc, sizeof(struct usb_device_descriptor));
-static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr,
- const char *in, size_t count)
+static ssize_t __usbip_sockfd_store(struct device *dev, struct device_attribute *attr,
+ const char *in, size_t count)
{
struct vudc *udc = (struct vudc *) dev_get_drvdata(dev);
int rv;
@@ -184,6 +184,17 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a
return ret;
}
+static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr,
+ const char *in, size_t count)
+{
+ ssize_t ret = usbip_event_lock_killable();
+
+ if (ret)
+ return ret;
+ ret = __usbip_sockfd_store(dev, attr, in, count);
+ usbip_event_unlock();
+ return ret;
+}
static DEVICE_ATTR_WO(usbip_sockfd);
static ssize_t usbip_status_show(struct device *dev,
--
2.18.4
