From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758750AbaGQXWg (ORCPT ); Thu, 17 Jul 2014 19:22:36 -0400 Received: from us-mx2.synaptics.com ([192.147.44.131]:32990 "EHLO us-mx2.synaptics.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758071AbaGQXWe (ORCPT ); Thu, 17 Jul 2014 19:22:34 -0400 X-PGP-Universal: processed; by securemail.synaptics.com on Thu, 17 Jul 2014 16:31:02 -0700 From: Andrew Duggan To: , CC: Andrew Duggan , Jiri Kosina , Benjamin Tissoires Subject: [PATCH v2] HID: rmi: check that report ids exist in the report_id_hash before accessing their size Date: Thu, 17 Jul 2014 16:14:44 -0700 Message-ID: <1405638885-8014-1-git-send-email-aduggan@synaptics.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.2.20.38] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is possible that the hid-rmi driver could get loaded onto a device which does not have the expected report ids. This should not happen because it would indicate that the hid-rmi driver is not compatible with that device. However, if it does happen it should return an error from probe instead of dereferencing a null pointer. related bug: https://bugzilla.kernel.org/show_bug.cgi?id=80091 Signed-off-by: Andrew Duggan --- Added hid_err messages as suggested by Benjamin. This fixes the null pointer dereference from bug 80091 while the next patch addresses the binding issue in hid-core. drivers/hid/hid-rmi.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c index 3221a95..260be7a 100644 --- a/drivers/hid/hid-rmi.c +++ b/drivers/hid/hid-rmi.c @@ -848,6 +848,8 @@ static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id) struct rmi_data *data = NULL; int ret; size_t alloc_size; + struct hid_report *input_report; + struct hid_report *output_report; data = devm_kzalloc(&hdev->dev, sizeof(struct rmi_data), GFP_KERNEL); if (!data) @@ -866,12 +868,26 @@ static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id) return ret; } - data->input_report_size = (hdev->report_enum[HID_INPUT_REPORT] - .report_id_hash[RMI_ATTN_REPORT_ID]->size >> 3) - + 1 /* report id */; - data->output_report_size = (hdev->report_enum[HID_OUTPUT_REPORT] - .report_id_hash[RMI_WRITE_REPORT_ID]->size >> 3) - + 1 /* report id */; + input_report = hdev->report_enum[HID_INPUT_REPORT] + .report_id_hash[RMI_ATTN_REPORT_ID]; + if (!input_report) { + hid_err(hdev, "device does not have expected input report\n"); + ret = -ENODEV; + return ret; + } + + data->input_report_size = (input_report->size >> 3) + 1 /* report id */; + + output_report = hdev->report_enum[HID_OUTPUT_REPORT] + .report_id_hash[RMI_WRITE_REPORT_ID]; + if (!output_report) { + hid_err(hdev, "device does not have expected output report\n"); + ret = -ENODEV; + return ret; + } + + data->output_report_size = (output_report->size >> 3) + + 1 /* report id */; alloc_size = data->output_report_size + data->input_report_size; -- 1.9.1