From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751792AbcBFHIr (ORCPT ); Sat, 6 Feb 2016 02:08:47 -0500 Received: from linuxhacker.ru ([217.76.32.60]:36726 "EHLO fiona.linuxhacker.ru" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751133AbcBFHIq (ORCPT ); Sat, 6 Feb 2016 02:08:46 -0500 X-Greylist: delayed 367 seconds by postgrey-1.27 at vger.kernel.org; Sat, 06 Feb 2016 02:08:46 EST From: green@linuxhacker.ru To: "Rafael J. Wysocki" , Len Brown , Thomas Renninger Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Oleg Drokin Subject: [PATCH] acpi/ec: Deny write access unless requested by module param Date: Sat, 6 Feb 2016 02:08:08 -0500 Message-Id: <1454742488-2231898-1-git-send-email-green@linuxhacker.ru> X-Mailer: git-send-email 2.1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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) { -- 2.1.0