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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 20CAFC4360C for ; Sun, 6 Oct 2019 17:38:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE5742173B for ; Sun, 6 Oct 2019 17:38:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383510; bh=lDQ0vRak90qAKBGgcQOhzIF+hJtm9oHmlBRzBXpF70A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SzYxxk5RwyI/VtBaF0EEz34HL/lGVDbFvROT3p5o/R54UsMzRlMH9nOhVhttOOtRw CUhDpPXc8mvGTrtK1eKzS24fKmJZ0Ho4AENM72XOVqEB+38e0RCQ+sZNq3ZbYLhUPr e/wWWLB1/O2m6rmKiumo3q7r7sCiNJ3lV80P5Zfw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730626AbfJFRi3 (ORCPT ); Sun, 6 Oct 2019 13:38:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:37670 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730606AbfJFRiZ (ORCPT ); Sun, 6 Oct 2019 13:38:25 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 E25DD2133F; Sun, 6 Oct 2019 17:38:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383505; bh=lDQ0vRak90qAKBGgcQOhzIF+hJtm9oHmlBRzBXpF70A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XNZ3LIemQmo1Mj0kkih/Tn30sz5O02Jyxuv5G7XVIp4YCSa3GAqCWprxbQGk8SwPO TylztE/lJ0q2wl757GwbhB3Kn+Hx6mEJoUhjwWr+C9HCm1aahR1689HQiRHIkR9p0f FLo/pHa4Ku1pehXBD4o0c8JVMWMbRrShbUopQ0Yw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexandre Ghiti , Kees Cook , Luis Chamberlain , Albert Ou , Alexander Viro , Catalin Marinas , Christoph Hellwig , Christoph Hellwig , James Hogan , Palmer Dabbelt , Paul Burton , Ralf Baechle , Russell King , Will Deacon , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 5.2 127/137] arm: properly account for stack randomization and stack guard gap Date: Sun, 6 Oct 2019 19:21:51 +0200 Message-Id: <20191006171219.914144952@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191006171209.403038733@linuxfoundation.org> References: <20191006171209.403038733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexandre Ghiti [ Upstream commit af0f4297286f13a75edf93677b1fb2fc16c412a7 ] This commit takes care of stack randomization and stack guard gap when computing mmap base address and checks if the task asked for randomization. This fixes the problem uncovered and not fixed for arm here: https://lkml.kernel.org/r/20170622200033.25714-1-riel@redhat.com Link: http://lkml.kernel.org/r/20190730055113.23635-7-alex@ghiti.fr Signed-off-by: Alexandre Ghiti Acked-by: Kees Cook Reviewed-by: Luis Chamberlain Cc: Albert Ou Cc: Alexander Viro Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Christoph Hellwig Cc: James Hogan Cc: Palmer Dabbelt Cc: Paul Burton Cc: Ralf Baechle Cc: Russell King Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- arch/arm/mm/mmap.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index f866870db749c..bff3d00bda5be 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -18,8 +18,9 @@ (((pgoff)<> (PAGE_SHIFT - 12)) static int mmap_is_legacy(struct rlimit *rlim_stack) { @@ -35,6 +36,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack) static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) { unsigned long gap = rlim_stack->rlim_cur; + unsigned long pad = stack_guard_gap; + + /* Account for stack randomization if necessary */ + if (current->flags & PF_RANDOMIZE) + pad += (STACK_RND_MASK << PAGE_SHIFT); + + /* Values close to RLIM_INFINITY can overflow. */ + if (gap + pad > gap) + gap += pad; if (gap < MIN_GAP) gap = MIN_GAP; -- 2.20.1