USB: gadget: validate interface OS descriptor requests

Stall the control endpoint in case provided index exceeds array size of
MAX_CONFIG_INTERFACES or when the retrieved function pointer is null.

Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 16f9e3423c9faaa59ddab3e8e62d36e49b2dd719..9315313108c9d50432ee80ba7b801b8a1e1c036b 100644 (file)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1988,6 +1988,9 @@ unknown:
                                if (w_index != 0x5 || (w_value >> 8))
                                        break;
                                interface = w_value & 0xFF;
+                               if (interface >= MAX_CONFIG_INTERFACES ||
+                                   !os_desc_cfg->interface[interface])
+                                       break;
                                buf[6] = w_index;
                                count = count_ext_prop(os_desc_cfg,
                                        interface);