[PATCH 4.9 27/34] USB: gadget: validate interface OS descriptor requests

Greg Kroah-Hartman
2022-02-14T09:31:37Z

From: Szymon Heidrich <szymon.heidrich@gmail.com>

commit 75e5b4849b81e19e9efe1654b30d7f3151c33c2c upstream.

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>
---
drivers/usb/gadget/composite.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1932,6 +1932,9 @@ 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;
if (w_length == 0x0A) {
count = count_ext_prop(os_desc_cfg,