From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Renninger Subject: Re: [PATCH] acpi/ec: Deny write access unless requested by module param Date: Wed, 17 Feb 2016 15:27:31 +0100 Message-ID: <2729982.5vh6UKHT1H@skinner> References: <1454742488-2231898-1-git-send-email-green@linuxhacker.ru> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:37572 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423401AbcBQO1d (ORCPT ); Wed, 17 Feb 2016 09:27:33 -0500 In-Reply-To: <1454742488-2231898-1-git-send-email-green@linuxhacker.ru> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: green@linuxhacker.ru Cc: "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org On Saturday, February 06, 2016 02:08:08 AM green@linuxhacker.ru wrote: > From: Oleg Drokin > > In debugfs it's not enough to just set file mode to read-only to > deny write access to a file, instead just don't provide > the write method unless write access is really requested. > > Signed-off-by: Oleg Drokin Signed-off-by: Thomas Renninger Thanks! > --- > I assume allowing run-time changes via /sys/module is preferrable, > opposed to forced module unload and reload to change this option, > but I can submit another patch to only depend on the module parameter > too, please let me know. > > drivers/acpi/ec_sys.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/acpi/ec_sys.c b/drivers/acpi/ec_sys.c > index bea8e42..6c7dd7a 100644 > --- a/drivers/acpi/ec_sys.c > +++ b/drivers/acpi/ec_sys.c > @@ -73,6 +73,9 @@ static ssize_t acpi_ec_write_io(struct file *f, const char > __user *buf, loff_t init_off = *off; > int err = 0; > > + if (!write_support) > + return -EINVAL; > + > if (*off >= EC_SPACE_SIZE) > return 0; > if (*off + count >= EC_SPACE_SIZE) {