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

[ Upstream commit 0b1d250afb8eb9d65afb568bac9b9f9253a82b49 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index 2ef757f35162681458ef14234f01e676eddaa6fb..c864f1d4fa2c585632e3d99afdca27d535f19792 100644 (file)
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -1546,6 +1546,12 @@ 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) {