USB: serial: kl5kusb105: fix line-state error handling

commit 146cc8a17a3b4996f6805ee5c080e7101277c410 upstream.

The current implementation failed to detect short transfers when
attempting to read the line state, and also, to make things worse,
logged the content of the uninitialised heap transfer buffer.

Fixes: abf492e7b3ae ("USB: kl5kusb105: fix DMA buffers on stack")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/usb/serial/kl5kusb105.c b/drivers/usb/serial/kl5kusb105.c
index 0ee190fc1bf8..6cb45757818f 100644
--- a/drivers/usb/serial/kl5kusb105.c
+++ b/drivers/usb/serial/kl5kusb105.c
@@ -192,10 +192,11 @@ static int klsi_105_get_line_state(struct usb_serial_port *port,
                              status_buf, KLSI_STATUSBUF_LEN,
                              10000
                              );
-        if (rc < 0)
-                dev_err(&port->dev, "Reading line status failed (error = %d)\n",
-                        rc);
-        else {
+        if (rc != KLSI_STATUSBUF_LEN) {
+                dev_err(&port->dev, "reading line status failed: %d\n", rc);
+                if (rc >= 0)
+                        rc = -EIO;
+        } else {
                 status = get_unaligned_le16(status_buf);
 
                 dev_info(&port->serial->dev->dev, "read status %x %x\n",