[PATCH 4.4 34/44] nfc: nci: fix the UAF of rf_conn_info object

[Greg Kroah-Hartman]

From: Lin Ma <linma@xxxxxxxxxx>

commit 1b1499a817c90fd1ce9453a2c98d2a01cca0e775 upstream.

The nci_core_conn_close_rsp_packet() function will release the conn_info
with given conn_id. However, it needs to set the rf_conn_info to NULL to
prevent other routines like nci_rf_intf_activated_ntf_packet() to trigger
the UAF.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx>
Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/nfc/nci/rsp.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/nfc/nci/rsp.c
+++ b/net/nfc/nci/rsp.c
@@ -274,6 +274,8 @@ static void nci_core_conn_close_rsp_pack
 		conn_info = nci_get_conn_info_by_conn_id(ndev, ndev->cur_id);
 		if (conn_info) {
 			list_del(&conn_info->list);
+			if (conn_info == ndev->rf_conn_info)
+				ndev->rf_conn_info = NULL;
 			devm_kfree(&ndev->nfc_dev->dev, conn_info);
 		}
 	}