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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 13507C43462 for ; Thu, 20 May 2021 11:26:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E460C6024A for ; Thu, 20 May 2021 11:26:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241561AbhETL1c (ORCPT ); Thu, 20 May 2021 07:27:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:38388 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239380AbhETLHi (ORCPT ); Thu, 20 May 2021 07:07:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 05E3561D37; Thu, 20 May 2021 10:05:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621505159; bh=Mvf0FNLedeZuBsf1fMjib3KJj6PXlybLW9Ols/CrO0Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bSIBSyNa0Q8+QBwHd4dN69NJZPmU1Bo8h8AizoQfzMohetDh6eHwari4MJ8XNbk5G 5QvaoUqhNHkvTu+DFtglTOfOM5njiteYFwnQtiDXHOSBJnntxrYfe4stM1yUhVrkn0 EBQIu8PJgRyla69S1gQNlHTJRVPUsofdQPvChQ2k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Caruso , Todd Poynor , Thomas Gleixner , Kasper Zwijsen Subject: [PATCH 4.4 001/190] timerfd: Reject ALARM timerfds without CAP_WAKE_ALARM Date: Thu, 20 May 2021 11:21:05 +0200 Message-Id: <20210520092102.199503505@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092102.149300807@linuxfoundation.org> References: <20210520092102.149300807@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Caruso commit 2895a5e5b3ae78d9923a91fce405d4a2f32c4309 upstream. timerfd gives processes a way to set wake alarms, but unlike timers made using timer_create, timerfds don't check whether the process has CAP_WAKE_ALARM before setting alarm-time timers. CAP_WAKE_ALARM is supposed to gate this behavior and so it makes sense that we should deny permission to create such timerfds if the process doesn't have this capability. Signed-off-by: Eric Caruso Cc: Todd Poynor Link: http://lkml.kernel.org/r/1465427339-96209-1-git-send-email-ejcaruso@chromium.org Signed-off-by: Thomas Gleixner Cc: Kasper Zwijsen Signed-off-by: Greg Kroah-Hartman --- fs/timerfd.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -400,6 +400,11 @@ SYSCALL_DEFINE2(timerfd_create, int, clo clockid != CLOCK_BOOTTIME_ALARM)) return -EINVAL; + if (!capable(CAP_WAKE_ALARM) && + (clockid == CLOCK_REALTIME_ALARM || + clockid == CLOCK_BOOTTIME_ALARM)) + return -EPERM; + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; @@ -444,6 +449,11 @@ static int do_timerfd_settime(int ufd, i return ret; ctx = f.file->private_data; + if (!capable(CAP_WAKE_ALARM) && isalarm(ctx)) { + fdput(f); + return -EPERM; + } + timerfd_setup_cancel(ctx, flags); /*