[PATCH 4.19 40/49] USB: gadget: validate interface OS descriptor requests

From: Greg Kroah-Hartman
Date: Mon Feb 14 2022 - 04:39:35 EST


From: Szymon Heidrich <szymon.heidrich@xxxxxxxxx>

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@xxxxxxxxx>
Cc: stable@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/composite.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1930,6 +1930,9 @@ 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);