Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756864Ab3I2Tq4 (ORCPT ); Sun, 29 Sep 2013 15:46:56 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59517 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755817Ab3I2T2m (ORCPT ); Sun, 29 Sep 2013 15:28:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Benjamin Tissoires , Kees Cook , Jiri Kosina Subject: [ 13/71] HID: multitouch: validate indexes details Date: Sun, 29 Sep 2013 12:27:25 -0700 Message-Id: <20130929192644.441182974@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.6.g82e253f.dirty In-Reply-To: <20130929192643.539596256@linuxfoundation.org> References: <20130929192643.539596256@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3320 Lines: 91 3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin Tissoires commit 8821f5dc187bdf16cfb32ef5aa8c3035273fa79a upstream. When working on report indexes, always validate that they are in bounds. Without this, a HID device could report a malicious feature report that could trick the driver into a heap overflow: [ 634.885003] usb 1-1: New USB device found, idVendor=0596, idProduct=0500 ... [ 676.469629] BUG kmalloc-192 (Tainted: G W ): Redzone overwritten Note that we need to change the indexes from s8 to s16 as they can be between -1 and 255. CVE-2013-2897 Signed-off-by: Benjamin Tissoires Acked-by: Kees Cook Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-multitouch.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -101,9 +101,9 @@ struct mt_device { unsigned last_slot_field; /* the last field of a slot */ unsigned mt_report_id; /* the report ID of the multitouch device */ unsigned pen_report_id; /* the report ID of the pen device */ - __s8 inputmode; /* InputMode HID feature, -1 if non-existent */ - __s8 inputmode_index; /* InputMode HID feature index in the report */ - __s8 maxcontact_report_id; /* Maximum Contact Number HID feature, + __s16 inputmode; /* InputMode HID feature, -1 if non-existent */ + __s16 inputmode_index; /* InputMode HID feature index in the report */ + __s16 maxcontact_report_id; /* Maximum Contact Number HID feature, -1 if non-existent */ __u8 num_received; /* how many contacts we received */ __u8 num_expected; /* expected last contact index */ @@ -317,20 +317,18 @@ static void mt_feature_mapping(struct hi struct hid_field *field, struct hid_usage *usage) { struct mt_device *td = hid_get_drvdata(hdev); - int i; switch (usage->hid) { case HID_DG_INPUTMODE: - td->inputmode = field->report->id; - td->inputmode_index = 0; /* has to be updated below */ - - for (i=0; i < field->maxusage; i++) { - if (field->usage[i].hid == usage->hid) { - td->inputmode_index = i; - break; - } + /* Ignore if value index is out of bounds. */ + if (usage->usage_index >= field->report_count) { + dev_err(&hdev->dev, "HID_DG_INPUTMODE out of range\n"); + break; } + td->inputmode = field->report->id; + td->inputmode_index = usage->usage_index; + break; case HID_DG_CONTACTMAX: td->maxcontact_report_id = field->report->id; @@ -536,6 +534,10 @@ static int mt_touch_input_mapping(struct mt_store_field(usage, td, hi); return 1; case HID_DG_CONTACTCOUNT: + /* Ignore if indexes are out of bounds. */ + if (field->index >= field->report->maxfield || + usage->usage_index >= field->report_count) + return 1; td->cc_index = field->index; td->cc_value_index = usage->usage_index; return 1; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/