From: Johan Hovold <johan@hovoldconsulting.com>
Date: Fri, 27 Mar 2015 11:45:46 +0000 (+0100)
Subject: greybus: hid: fix null-deref on short report requests
X-Git-Tag: v4.9-rc1~119^2~378^2~21^2~1629
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=36257f6b4e7671cb12f98d91a6ffdeabdc254d0c;p=karo-tx-linux.git

greybus: hid: fix null-deref on short report requests

Make sure to verify the length of incoming requests before trying to
parse the request buffer, which can even be NULL on empty requests.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
---

diff --git a/drivers/staging/greybus/hid.c b/drivers/staging/greybus/hid.c
index f0da387476b8..a225813bc477 100644
--- a/drivers/staging/greybus/hid.c
+++ b/drivers/staging/greybus/hid.c
@@ -163,6 +163,11 @@ static void gb_hid_irq_handler(u8 type, struct gb_operation *op)
 		return;
 	}
 
+	if (op->request->payload_size < 2) {
+		dev_err(&connection->dev, "short report received\n");
+		return;
+	}
+
 	size = request->report[0] | request->report[1] << 8;
 	if (!size) {
 		dev_err(&connection->dev, "bad report size: %d\n", size);