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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 8B794C3A5A2 for ; Tue, 10 Sep 2019 11:57:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59C98208E4 for ; Tue, 10 Sep 2019 11:57:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733236AbfIJL5q (ORCPT ); Tue, 10 Sep 2019 07:57:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51316 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725818AbfIJL5q (ORCPT ); Tue, 10 Sep 2019 07:57:46 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E5FD418EF684; Tue, 10 Sep 2019 11:57:45 +0000 (UTC) Received: from asgard.redhat.com (ovpn-112-63.ams2.redhat.com [10.36.112.63]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 241D819C78; Tue, 10 Sep 2019 11:57:37 +0000 (UTC) Date: Tue, 10 Sep 2019 12:57:11 +0100 From: Eugene Syromiatnikov To: linux-kernel@vger.kernel.org, Christian Brauner Cc: Andrew Morton , "Peter Zijlstra (Intel)" , Ingo Molnar , "Dmitry V. Levin" , Eric Biederman , Oleg Nesterov Subject: [PATCH] fork: fail on non-zero higher 32 bits of args.exit_signal Message-ID: <20190910115711.GA3755@asgard.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.63]); Tue, 10 Sep 2019 11:57:46 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Previously, higher 32 bits of exit_signal fields were lost when copied to the kernel args structure (that uses int as a type for the respective field). Fail with EINVAL if these are set as it looks like there's no sane reason to accept them. * kernel/fork.c (copy_clone_args_from_user): Fail with -EINVAL if args.exit_signal converted to unsigned int is not equal to the original value. Signed-off-by: Eugene Syromiatnikov --- kernel/fork.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/fork.c b/kernel/fork.c index 2852d0e..fcbc4d5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2562,6 +2562,9 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, if (copy_from_user(&args, uargs, size)) return -EFAULT; + if (unlikely(((unsigned int)args.exit_signal) != args.exit_signal)) + return -EINVAL; + *kargs = (struct kernel_clone_args){ .flags = args.flags, .pidfd = u64_to_user_ptr(args.pidfd), -- 2.1.4