Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752871AbaGAGzS (ORCPT ); Tue, 1 Jul 2014 02:55:18 -0400 Received: from cantor2.suse.de ([195.135.220.15]:55813 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750869AbaGAGzQ (ORCPT ); Tue, 1 Jul 2014 02:55:16 -0400 Date: Tue, 1 Jul 2014 08:55:13 +0200 (CEST) From: Jiri Kosina To: Mateusz Guzik cc: Nicholas Krause , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] hid-appleir: Fix kernel panic due to null pointer In-Reply-To: <20140701065021.GA887@mguzik.redhat.com> Message-ID: References: <1404180865-3681-1-git-send-email-xerofoify@gmail.com> <20140701065021.GA887@mguzik.redhat.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 Jul 2014, Mateusz Guzik wrote: > > > Fixes a null pointer in appleir_input_configured due to reading > > > into wrong size array. Changed the variable to input_dev->keycodemax. > > > > This is a stale changelog from the previous buggy version. > > > > > Signed-off-by: Nicholas Krause > > > --- > > > drivers/hid/hid-appleir.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/hid/hid-appleir.c b/drivers/hid/hid-appleir.c > > > index 0e6a42d..cc02df4 100644 > > > --- a/drivers/hid/hid-appleir.c > > > +++ b/drivers/hid/hid-appleir.c > > > @@ -272,7 +272,7 @@ static void appleir_input_configured(struct hid_device *hid, > > > input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_REP); > > > > > > memcpy(appleir->keymap, appleir_key_table, sizeof(appleir->keymap)); > > > - for (i = 0; i < ARRAY_SIZE(appleir_key_table); i++) > > > + for (i = 0; i < appleir->keymap; i++) > > > > This is wrong. appleir->keymap is an array, and you want to count its > > elements. > > > > But where the claim of 'null pointer' is coming from (or reading/writing > past the array for that matter)? > > Replacing appleir_key_table with appleir->keymap is a noop anyway > because: > unsigned short keymap[ARRAY_SIZE(appleir_key_table)]; It's not really equivalent. ARRAY_SIZE counts the number of short-sized elements, sizeof() counts the number of bytes that fit into the data structure (which is twice as much, as sizeof(unsigned short) == 2). -- Jiri Kosina SUSE Labs -- 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/