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=-6.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 8423CC282C4 for ; Tue, 12 Feb 2019 14:55:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5211521773 for ; Tue, 12 Feb 2019 14:55:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jxzgyLK3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730599AbfBLOzG (ORCPT ); Tue, 12 Feb 2019 09:55:06 -0500 Received: from mail-yw1-f68.google.com ([209.85.161.68]:39646 "EHLO mail-yw1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730581AbfBLOzB (ORCPT ); Tue, 12 Feb 2019 09:55:01 -0500 Received: by mail-yw1-f68.google.com with SMTP id k188so1096720ywa.6; Tue, 12 Feb 2019 06:55:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=RBi4iWHzkOTf6erCHihsCZEcXXpaip/u9aLYjX+/qYo=; b=jxzgyLK3E/2hzKKmOdEr+FLZtRgeRc+YbXVOpT9u0DxZX0EgdBLFExYMySREDj6yjF yQ7Km9P/eL+6Gm8PAcKrsshN9dUL0BEttEfIUhIMGCuon7DPHpx65gE2OzPI92c5vjtU ukZG3Nsj42Sdu0RMFQXeZk0M0w45x770JSEIPyhamGFl+qn2JdUXexy0yvAUkfa7gQTS kphe+zEydlRzTiz6DFX0sqmdEL+MtxaHqC3FOSX8yGH/w2O5yum2sSlTpaRRKqgcvSEI jp1JePufDPJeMq1g82POl5KDBAmKmDUzP+y6Ul5Rk6OscwyXPaEjpLy/D3ZcX9byfsGY 8JeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=RBi4iWHzkOTf6erCHihsCZEcXXpaip/u9aLYjX+/qYo=; b=qEB/dORd31PE31icBRJjMnz0kEmCWi/VNGjQFvC1Alvu9JDsMm2XB/N8qsr4kzjMvJ mIq1l4T/QvgDQDzvi+XnC8o2CdlAj/MnuGogRYiZiWcuw6DUrTdEovY6YpANn0bTK2q/ BLYM2gEpANWV/m+AFD3b9cyPx9oopkJXn+QnIqP3U9b3phi8+8yytzBXiXeMvYGkvZ0i SmLQPJb1AG5EqG1pAwK26gLhiYMyi7UFvAYsmmguc5JIkIQQPRgkaHxlZVWZpEk0DldQ y77qymPtmhLSn9tKGkpMgl2eK7/4q4AwtU7Drt66Tryxq/CI6xSYT0rMdqyT9mFWsJk5 dL3w== X-Gm-Message-State: AHQUAuaXpUsbJk/iq31LXuKQG9ZyAj+KkAkVjc8+cF9e/6slbZxaBV9N PsHKzSytsVwveU6L2mDkrIWVGrIoH+hqrQ== X-Google-Smtp-Source: AHgI3IZvaQAI0dqXCpVYiCcvGd/s+4YOleD1vbbBKVAcMLckw/MtOjrqG7RK3pqX/PBW1XPkvkc28g== X-Received: by 2002:a0d:cc08:: with SMTP id o8mr324963ywd.506.1549983301028; Tue, 12 Feb 2019 06:55:01 -0800 (PST) Received: from localhost.localdomain (c-73-120-18-128.hsd1.tn.comcast.net. [73.120.18.128]) by smtp.gmail.com with ESMTPSA id v134sm4987967ywv.90.2019.02.12.06.54.59 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 12 Feb 2019 06:55:00 -0800 (PST) From: demiobenour@gmail.com To: Alexander Viro , linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), linux-kernel@vger.kernel.org (open list) Cc: "Demi M. Obenour" Subject: [PATCH 4/4] Return -EINVAL if userspace passes bogus flags to open() Date: Tue, 12 Feb 2019 09:54:47 -0500 Message-Id: <20190212145450.2200-4-demiobenour@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190212145450.2200-1-demiobenour@gmail.com> References: <20190212145450.2200-1-demiobenour@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: "Demi M. Obenour" While testing the O_PATHSTATIC patch, I discovered that Linux does not return any error if an invalid flag is passed to open(2). This prevents adding new flags without a (minor) risk of breaking userspace. Therefore, add a check for invalid flags, and return -EINVAL if any are found. --- fs/open.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/open.c b/fs/open.c index 717afa8179c0..eeaa2eeb342a 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1074,6 +1074,13 @@ long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode) if (fd) return fd; + /* + * Enforce that open flags are valid, to ensure that new flags can be + * added later. + */ + if (unlikely(flags & ~VALID_OPEN_FLAGS)) + return -EINVAL; + tmp = getname(filename); if (IS_ERR(tmp)) return PTR_ERR(tmp); -- 2.20.1