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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 EE99FC432C0 for ; Mon, 18 Nov 2019 20:54:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C33732230C for ; Mon, 18 Nov 2019 20:54:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574110499; bh=TCcCWzt+woiXDfMa33gUEmmxlLgYw/oRawWE+pFh2tQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=U3GlvxBckzoTTZ/X4NweTbPZUkGKEbZ9lKR2XGAGpdMZ52xQOwbkPt2yc+aYp1CEL +YkVQLXMps4J+njO4YljjebxDqV3bUEiPhNhdE982W1A34dblxBdosA7+bUtJHqtGW Fjm6edG5j9v5JjkwZlmaYi7tiobakvam69qOKLFY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726759AbfKRUy6 (ORCPT ); Mon, 18 Nov 2019 15:54:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:53598 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726568AbfKRUy6 (ORCPT ); Mon, 18 Nov 2019 15:54:58 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC2A42230C; Mon, 18 Nov 2019 20:54:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574110498; bh=TCcCWzt+woiXDfMa33gUEmmxlLgYw/oRawWE+pFh2tQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Fw3Oo/M7wub+tVFG/tjWRtkQo9IgZ1fCUAsprnMwj9wsIN3hb7axv3ZE2JmIchCPt Mc5MFm+xg8eLnKiLlotW7GUMBcNjaoWHQ5GoqXkv0dbNx0LVDQa/ybIC60+wOLnd11 E0QC5jRjM9F2aKqy7plh2+VrGWz0YLhrAqt9XIY0= Date: Mon, 18 Nov 2019 12:54:57 -0800 From: Andrew Morton To: Alexey Dobriyan Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, security@kernel.org Subject: Re: [PATCH] ELF: warn if process starts with executable stack Message-Id: <20191118125457.778e44dfd4740d24795484c7@linux-foundation.org> In-Reply-To: <20191118145114.GA9228@avx2> References: <20191118145114.GA9228@avx2> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 18 Nov 2019 17:51:15 +0300 Alexey Dobriyan wrote: > PT_GNU_STACK is fail open design, Not sure what this means. Please expand on the motivation for this change. > at least warn people that something > isn't right. People who use an executable stack get a kernel splat. How is that useful? > ... > > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -762,6 +762,13 @@ int setup_arg_pages(struct linux_binprm *bprm, > goto out_unlock; > BUG_ON(prev != vma); > > +#ifdef CONFIG_MMU > + if (vm_flags & VM_EXEC) { > + pr_warn_once("process '%s'/%u started with executable stack\n", > + current->comm, current->pid); > + } > +#endif > > /* Move stack pages down in memory. */ > if (stack_shift) { > ret = shift_arg_pages(vma, stack_shift);