usbip: fix vhci_hcd to check for stream socket

Fix attach_store() to validate the passed in file descriptor is a
stream socket. If the file descriptor passed was a SOCK_DGRAM socket,
sock_recvmsg() can't detect end of stream.

Cc: stable@vger.kernel.org
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/52712aa308915bda02cece1589e04ee8b401d1f3.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: shuahkh

drivers/usb/usbip/vhci_sysfs.c

@@ -349,8 +349,16 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr,
 
 	/* Extract socket from fd. */
 	socket = sockfd_lookup(sockfd, &err);
-	if (!socket)
+	if (!socket) {
+		dev_err(dev, "failed to lookup sock");
 		return -EINVAL;
+	}
+	if (socket->type != SOCK_STREAM) {
+		dev_err(dev, "Expecting SOCK_STREAM - found %d",
+			socket->type);
+		sockfd_put(socket);
+		return -EINVAL;
+	}
 
 	/* now need lock until setting vdev status as used */