USB: serial: whiteheat: fix potential slab corruption

BugLink: https://bugs.launchpad.net/bugs/1852492
commit 1251dab9e0a2c4d0d2d48370ba5baa095a5e8774 upstream.

Fix a user-controlled slab buffer overflow due to a missing sanity check
on the bulk-out transfer buffer used for control requests.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191029102354.2733-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/usb/serial/whiteheat.c b/drivers/usb/serial/whiteheat.c
index 1c7b46a8620cc039847bcdbbb814f76576a53e41..fb2f90726d357515a804a4bedd69e3e92c8410b2 100644 (file)
--- a/drivers/usb/serial/whiteheat.c
+++ b/drivers/usb/serial/whiteheat.c
@@ -571,6 +571,10 @@ static int firm_send_command(struct usb_serial_port *port, __u8 command,
 
        command_port = port->serial->port[COMMAND_PORT];
        command_info = usb_get_serial_port_data(command_port);
+
+       if (command_port->bulk_out_size < datasize + 1)
+               return -EIO;
+
        mutex_lock(&command_info->mutex);
        command_info->command_finished = false;