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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 6F9B7C43219 for ; Thu, 2 May 2019 20:52:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A3682085A for ; Thu, 2 May 2019 20:52:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726444AbfEBUwn (ORCPT ); Thu, 2 May 2019 16:52:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725962AbfEBUwl (ORCPT ); Thu, 2 May 2019 16:52:41 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id EA8CD3151C44; Thu, 2 May 2019 20:52:40 +0000 (UTC) Received: from jsavitz.bos.com (dhcp-17-168.bos.redhat.com [10.18.17.168]) by smtp.corp.redhat.com (Postfix) with ESMTP id 14B595D9C4; Thu, 2 May 2019 20:52:39 +0000 (UTC) From: Joel Savitz To: linux-kernel@vger.kernel.org Cc: Joel Savitz , Thomas Gleixner , Ingo Molnar , Masami Hiramatsu , Waiman Long , Mauro Carvalho Chehab , Kristina Martsenko , Andrew Morton , Cyrill Gorcunov , Kees Cook , "Gustavo A. R. Silva" , YueHaibing , Micah Morton , Yang Shi , Jann Horn , Alexey Dobriyan , Rafael Aquini , Michael Kerrisk , Yury Norov Subject: [PATCH v2 1/2] kernel/sys: add PR_GET_TASK_SIZE option to prctl(2) Date: Thu, 2 May 2019 16:52:21 -0400 Message-Id: <1556830342-32307-2-git-send-email-jsavitz@redhat.com> In-Reply-To: <1556830342-32307-1-git-send-email-jsavitz@redhat.com> References: <1556830342-32307-1-git-send-email-jsavitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Thu, 02 May 2019 20:52:41 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When PR_GET_TASK_SIZE is passed to prctl, the kernel will attempt to copy the value of TASK_SIZE to the userspace address in arg2. Suggested-by: Alexey Dobriyan Signed-off-by: Joel Savitz --- include/uapi/linux/prctl.h | 3 +++ kernel/sys.c | 10 ++++++++++ 2 files changed, 13 insertions(+) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 094bb03b9cc2..2335fe0a8db8 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -229,4 +229,7 @@ struct prctl_mm_map { # define PR_PAC_APDBKEY (1UL << 3) # define PR_PAC_APGAKEY (1UL << 4) +/* Get the process virtual memory size */ +#define PR_GET_TASK_SIZE 55 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 12df0e5434b8..7ced7dbd035d 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2252,6 +2252,13 @@ static int propagate_has_child_subreaper(struct task_struct *p, void *data) return 1; } +static int prctl_get_tasksize(void __user * uaddr) +{ + unsigned long task_size = TASK_SIZE; + return copy_to_user(uaddr, &task_size, sizeof(unsigned long)) + ? -EFAULT : 0; +} + int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which) { return -EINVAL; @@ -2486,6 +2493,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EINVAL; error = PAC_RESET_KEYS(me, arg2); break; + case PR_GET_TASK_SIZE: + error = prctl_get_tasksize((void *)arg2) ; + break; default: error = -EINVAL; break; -- 2.18.1