From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Wu Subject: [PATCH 2/3] HID: logitech-{dj,hidpp}: check report length Date: Tue, 16 Dec 2014 01:50:15 +0100 Message-ID: <1418691016-30681-3-git-send-email-peter@lekensteyn.nl> References: <1418691016-30681-1-git-send-email-peter@lekensteyn.nl> Return-path: Received: from lekensteyn.nl ([178.21.112.251]:59213 "EHLO lekensteyn.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796AbaLPAud (ORCPT ); Mon, 15 Dec 2014 19:50:33 -0500 In-Reply-To: <1418691016-30681-1-git-send-email-peter@lekensteyn.nl> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Jiri Kosina , Benjamin Tissoires , Nestor Lopez Casado Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Malicious USB devices can send bogus reports smaller than the expected buffer size. Ensure that the length is valid to avoid reading out of bounds. For the old WTP, I do not have a HID descriptor so just check for the minimum length in hidpp_raw_event (this can be changed to an inequality later). Signed-off-by: Peter Wu --- Hi, If you know that the WTP report (ID 2) has a length of 2, then you can change "<" to "!=" and remove the paragraph from the commit message. Kind regards, Peter --- drivers/hid/hid-logitech-dj.c | 16 +++++++++++++++- drivers/hid/hid-logitech-hidpp.c | 12 +++++++++--- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c index c917ab6..5bc6d80 100644 --- a/drivers/hid/hid-logitech-dj.c +++ b/drivers/hid/hid-logitech-dj.c @@ -962,10 +962,24 @@ static int logi_dj_raw_event(struct hid_device *hdev, switch (data[0]) { case REPORT_ID_DJ_SHORT: + if (size != DJREPORT_SHORT_LENGTH) { + dev_err(&hdev->dev, "DJ report of bad size (%d)", size); + return false; + } return logi_dj_dj_event(hdev, report, data, size); case REPORT_ID_HIDPP_SHORT: - /* intentional fallthrough */ + if (size != HIDPP_REPORT_SHORT_LENGTH) { + dev_err(&hdev->dev, + "Short HID++ report of bad size (%d)", size); + return false; + } + return logi_dj_hidpp_event(hdev, report, data, size); case REPORT_ID_HIDPP_LONG: + if (size != HIDPP_REPORT_LONG_LENGTH) { + dev_err(&hdev->dev, + "Long HID++ report of bad size (%d)", size); + return false; + } return logi_dj_hidpp_event(hdev, report, data, size); } diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c index ae23dec..2315358 100644 --- a/drivers/hid/hid-logitech-hidpp.c +++ b/drivers/hid/hid-logitech-hidpp.c @@ -992,11 +992,17 @@ static int hidpp_raw_event(struct hid_device *hdev, struct hid_report *report, return 1; } return hidpp_raw_hidpp_event(hidpp, data, size); + case 0x02: + if (size < 2) { + hid_err(hdev, "Received HID report of bad size (%d)", + size); + return 1; + } + if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) + return wtp_raw_event(hdev, data, size); + return 1; } - if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) - return wtp_raw_event(hdev, data, size); - return 0; } -- 2.1.3