From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:39676 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752475AbdJaJzf (ORCPT ); Tue, 31 Oct 2017 05:55:35 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Konovalov , Dmitry Torokhov Subject: [PATCH 4.4 10/20] Input: gtco - fix potential out-of-bound access Date: Tue, 31 Oct 2017 10:55:26 +0100 Message-Id: <20171031095510.706625629@linuxfoundation.org> In-Reply-To: <20171031095510.079198256@linuxfoundation.org> References: <20171031095510.079198256@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Torokhov commit a50829479f58416a013a4ccca791336af3c584c7 upstream. parse_hid_report_descriptor() has a while (i < length) loop, which only guarantees that there's at least 1 byte in the buffer, but the loop body can read multiple bytes which causes out-of-bounds access. Reported-by: Andrey Konovalov Reviewed-by: Andrey Konovalov Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman --- drivers/input/tablet/gtco.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) --- a/drivers/input/tablet/gtco.c +++ b/drivers/input/tablet/gtco.c @@ -231,13 +231,17 @@ static void parse_hid_report_descriptor( /* Walk this report and pull out the info we need */ while (i < length) { - prefix = report[i]; - - /* Skip over prefix */ - i++; + prefix = report[i++]; /* Determine data size and save the data in the proper variable */ - size = PREF_SIZE(prefix); + size = (1U << PREF_SIZE(prefix)) >> 1; + if (i + size > length) { + dev_err(ddev, + "Not enough data (need %d, have %d)\n", + i + size, length); + break; + } + switch (size) { case 1: data = report[i]; @@ -245,8 +249,7 @@ static void parse_hid_report_descriptor( case 2: data16 = get_unaligned_le16(&report[i]); break; - case 3: - size = 4; + case 4: data32 = get_unaligned_le32(&report[i]); break; }