From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,URIBL_DBL_ABUSE_MALW, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30C96ECE561 for ; Mon, 24 Sep 2018 12:41:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA0FA2083A for ; Mon, 24 Sep 2018 12:41:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA0FA2083A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388795AbeIXSna (ORCPT ); Mon, 24 Sep 2018 14:43:30 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59150 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729543AbeIXSna (ORCPT ); Mon, 24 Sep 2018 14:43:30 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 848FF109F; Mon, 24 Sep 2018 12:41:32 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bartosz Golaszewski , Linus Walleij , Sasha Levin Subject: [PATCH 4.18 177/235] gpiolib: dont allow userspace to set values of input lines Date: Mon, 24 Sep 2018 13:52:43 +0200 Message-Id: <20180924113122.447077803@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bartosz Golaszewski [ Upstream commit e5332d5437764f775cf4e3b8ca3bf592af063a02 ] User space can currently both read and set values of input lines using the character device. This was not allowed by the old sysfs interface nor is it a correct behavior. Check the first descriptor in the set for the OUT flag when asked to set values and return -EPERM if the line is input. Signed-off-by: Bartosz Golaszewski Signed-off-by: Linus Walleij Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpio/gpiolib.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -449,7 +449,13 @@ static long linehandle_ioctl(struct file return 0; } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) { - /* TODO: check if descriptors are really output */ + /* + * All line descriptors were created at once with the same + * flags so just check if the first one is really output. + */ + if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags)) + return -EPERM; + if (copy_from_user(&ghd, ip, sizeof(ghd))) return -EFAULT;