From mboxrd@z Thu Jan 1 00:00:00 1970 From: Seth Forshee Subject: [PATCH] HID: i2c-hid: Limit reads to wMaxInputLength bytes for input events Date: Fri, 20 Feb 2015 11:45:11 -0600 Message-ID: <1424454311-70750-1-git-send-email-seth.forshee@canonical.com> Return-path: Received: from mail-oi0-f52.google.com ([209.85.218.52]:47889 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754421AbbBTRpd (ORCPT ); Fri, 20 Feb 2015 12:45:33 -0500 Received: by mail-oi0-f52.google.com with SMTP id u20so3802436oif.11 for ; Fri, 20 Feb 2015 09:45:32 -0800 (PST) Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Jiri Kosina Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Seth Forshee , Benjamin Tissoires d1c7e29e8d27 (HID: i2c-hid: prevent buffer overflow in early IRQ) changed hid_get_input() to read ihid->bufsize bytes, which can be more than wMaxInputLength. This is the case with the Dell XPS 13 9343, and it is causing events to be missed. In some cases the missed events are releases, which can cause the cursor to jump or freeze, among other problems. Limit the number of bytes read to min(wMaxInputLength, ihid->bufsize) to prevent such problems. Fixes: d1c7e29e8d27 "HID: i2c-hid: prevent buffer overflow in early IRQ" Cc: Benjamin Tissoires Signed-off-by: Seth Forshee --- drivers/hid/i2c-hid/i2c-hid.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index d43e967..5e72fc2 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -370,7 +370,10 @@ static int i2c_hid_hwreset(struct i2c_client *client) static void i2c_hid_get_input(struct i2c_hid *ihid) { int ret, ret_size; - int size = ihid->bufsize; + int size = le16_to_cpu(ihid->hdesc.wMaxInputLength); + + if (size > ihid->bufsize) + size = ihid->bufsize; ret = i2c_master_recv(ihid->client, ihid->inbuf, size); if (ret != size) { -- 1.9.1