USB: serial: keyspan_pda: fix modem-status error handling

Fix broken modem-status error handling which could lead to bits of slab
data leaking to user space.

Fixes: 3b36a8fd6777 ("usb: fix uninitialized variable warning in keyspan_pda")
Cc: stable <stable@vger.kernel.org>     # 2.6.27
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 5169624d8b11..38d43c4b7ce5 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -369,8 +369,10 @@ static int keyspan_pda_get_modem_info(struct usb_serial *serial,
                              3, /* get pins */
                              USB_TYPE_VENDOR|USB_RECIP_INTERFACE|USB_DIR_IN,
                              0, 0, data, 1, 2000);
-        if (rc >= 0)
+        if (rc == 1)
                 *value = *data;
+        else if (rc >= 0)
+                rc = -EIO;
 
         kfree(data);
         return rc;