From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Tissoires Subject: Re: [PATCH] HID: i2c-hid: Limit reads to wMaxInputLength bytes for input events Date: Fri, 20 Feb 2015 14:38:30 -0500 Message-ID: <20150220193830.GB15471@mail.corp.redhat.com> References: <1424454311-70750-1-git-send-email-seth.forshee@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:33137 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751545AbbBTTii (ORCPT ); Fri, 20 Feb 2015 14:38:38 -0500 Content-Disposition: inline In-Reply-To: <1424454311-70750-1-git-send-email-seth.forshee@canonical.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Seth Forshee Cc: Jiri Kosina , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org On Feb 20 2015 or thereabouts, Seth Forshee wrote: > 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 Reviewed-by: Benjamin Tissoires Thanks! Benjamin > --- > 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 >