USB: serial: io_ti: fix NULL-deref in interrupt callback

Fix a NULL-pointer dereference in the interrupt callback should a
malicious device send data containing a bad port number by adding the
missing sanity check.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index ceaeebaa6f90..4561dd4cde8b 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -1674,6 +1674,12 @@ static void edge_interrupt_callback(struct urb *urb)
         function    = TIUMP_GET_FUNC_FROM_CODE(data[0]);
         dev_dbg(dev, "%s - port_number %d, function %d, info 0x%x\n", __func__,
                 port_number, function, data[1]);
+
+        if (port_number >= edge_serial->serial->num_ports) {
+                dev_err(dev, "bad port number %d\n", port_number);
+                goto exit;
+        }
+
         port = edge_serial->serial->port[port_number];
         edge_port = usb_get_serial_port_data(port);
         if (!edge_port) {