[PATCH 4.17 19/21] Bluetooth: hidp: buffer overflow in hidp_process_report

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mark Salyzyn <redacted>

commit 7992c18810e568b95c869b227137a2215702a805 upstream.

CVE-2018-9363

The buffer length is unsigned at all layers, but gets cast to int and
checked in hidp_process_report and can lead to a buffer overflow.
Switch len parameter to unsigned int to resolve issue.

This affects 3.18 and newer kernels.

Signed-off-by: Mark Salyzyn <redacted>
Fixes: a4b1b5877b514b276f0f31efe02388a9c2836728 ("HID: Bluetooth: hidp: make sure input buffers are big enough")
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Kees Cook <redacted>
Cc: Benjamin Tissoires <redacted>
Cc: linux-bluetooth@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: security@kernel.org
Cc: kernel-team@android.com
Acked-by: Kees Cook <redacted>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/bluetooth/hidp/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c

@@ -431,8 +431,8 @@ static void hidp_del_timer(struct hidp_s
 		del_timer(&session->timer);
 }
 
-static void hidp_process_report(struct hidp_session *session,
-				int type, const u8 *data, int len, int intr)
+static void hidp_process_report(struct hidp_session *session, int type,
+				const u8 *data, unsigned int len, int intr)
 {
 	if (len > HID_MAX_BUFFER_SIZE)
 		len = HID_MAX_BUFFER_SIZE;