Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933539AbaLKBeF (ORCPT ); Wed, 10 Dec 2014 20:34:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43359 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933440AbaLKBeD (ORCPT ); Wed, 10 Dec 2014 20:34:03 -0500 Date: Wed, 10 Dec 2014 20:33:50 -0500 From: Benjamin Tissoires To: Peter Wu Cc: Jiri Kosina , Nestor Lopez Casado , Peter Hutterer , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] HID: logitech-hidpp: do not return the name length Message-ID: <20141211013350.GE4861@mail.corp.redhat.com> References: <1418250070-28604-1-git-send-email-benjamin.tissoires@redhat.com> <4561294.qneDZ51mgu@al> <20141210230152.GC4861@mail.corp.redhat.com> <1906623.oO6IMXUbli@al> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1906623.oO6IMXUbli@al> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Dec 11 2014 or thereabouts, Peter Wu wrote: > On Wednesday 10 December 2014 18:01:52 Benjamin Tissoires wrote: > > On Dec 10 2014 or thereabouts, Peter Wu wrote: > > > On Wednesday 10 December 2014 17:21:09 Benjamin Tissoires wrote: > > > > We do not make any use of the actual name length get through > > > > hidpp_get_device_name(). > > > > > > > > We can drop the extra code and simplify the API a bit. > > > > > > > > Signed-off-by: Benjamin Tissoires > > > > > > > > --- > > > > drivers/hid/hid-logitech-hidpp.c | 10 +++------- > > > > 1 file changed, 3 insertions(+), 7 deletions(-) > > > > > > > > diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c > > > > index 1a6395d..3846305 100644 > > > > --- a/drivers/hid/hid-logitech-hidpp.c > > > > +++ b/drivers/hid/hid-logitech-hidpp.c > > > > @@ -461,7 +461,7 @@ static int hidpp_devicenametype_get_device_name(struct hidpp_device *hidpp, > > > > return count; > > > > } > > > > > > > > -static char *hidpp_get_device_name(struct hidpp_device *hidpp, u8 *name_length) > > > > +static char *hidpp_get_device_name(struct hidpp_device *hidpp) > > > > { > > > > u8 feature_type; > > > > u8 feature_index; > > > > @@ -484,7 +484,6 @@ static char *hidpp_get_device_name(struct hidpp_device *hidpp, u8 *name_length) > > > > if (!name) > > > > goto out_err; > > > > > > > > - *name_length = __name_length + 1; > > > > while (index < __name_length) > > > > index += hidpp_devicenametype_get_device_name(hidpp, > > > > feature_index, index, name + index, > > > > > > hidpp_devicenametype_get_device_name can return a non-positive value if > > > the USB device is unplugged at the wrong time, or if a malicious device > > > is attached (and 0 is returned). An infinite loop is the result. > > > > Oh, yes, you are definitively right. > > > > > > > > Can you apply this change in the patch or should I send you a separate > > > one? > > > > Feel free to send your patch directly to the list. > > > > > > > > while (index < __name_length) { > > > ret = hidpp_devicenametype_get_device_name(hidpp, > > > feature_index, index, name + index, > > > __name_length - index); > > > if (ret <= 0) { > > > kfree(name); > > > return NULL; > > > } > > > index += ret; > > > } > > > > > > > @@ -493,7 +492,6 @@ static char *hidpp_get_device_name(struct hidpp_device *hidpp, u8 *name_length) > > > > return name; > > > > > > > > out_err: > > > > - *name_length = 0; > > > > return NULL; > > > > > > What about dropping the label out_err here and returning NULL in the > > > previous places? > > > > Yep, good idea. You can either send a patch for that if you want to take > > credits, or I can send a v2. It's up to you. > > > > Cheers, > > Benjamin > > I found another place where a boundary check is missing, but will treat > that in a separate patch. If you send a v2 with the return NULL fixed > up, I'll base my patch (to add a retval check) on yours. OK. I am not sure I will be able to make it today or tomorrow. Feel free to send the fixes right now if you can manage to send them now. Cheers, Benjamin > > Kind regards, > Peter > > > > > > > > } > > > > > > > > @@ -989,7 +987,6 @@ static void hidpp_overwrite_name(struct hid_device *hdev, bool use_unifying) > > > > { > > > > struct hidpp_device *hidpp = hid_get_drvdata(hdev); > > > > char *name; > > > > - u8 name_length; > > > > > > > > if (use_unifying) > > > > /* > > > > @@ -999,7 +996,7 @@ static void hidpp_overwrite_name(struct hid_device *hdev, bool use_unifying) > > > > */ > > > > name = hidpp_get_unifying_name(hidpp); > > > > else > > > > - name = hidpp_get_device_name(hidpp, &name_length); > > > > + name = hidpp_get_device_name(hidpp); > > > > > > > > if (!name) > > > > hid_err(hdev, "unable to retrieve the name of the device"); > > > > @@ -1053,7 +1050,6 @@ static void hidpp_connect_event(struct hidpp_device *hidpp) > > > > bool connected = atomic_read(&hidpp->connected); > > > > struct input_dev *input; > > > > char *name, *devm_name; > > > > - u8 name_length; > > > > > > > > if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) > > > > wtp_connect(hdev, connected); > > > > @@ -1080,7 +1076,7 @@ static void hidpp_connect_event(struct hidpp_device *hidpp) > > > > return; > > > > } > > > > > > > > - name = hidpp_get_device_name(hidpp, &name_length); > > > > + name = hidpp_get_device_name(hidpp); > > > > if (!name) { > > > > hid_err(hdev, "unable to retrieve the name of the device"); > > > > } else { > > > > > -- 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/