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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 51ED7C352A9 for ; Sun, 29 Sep 2019 17:35:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28AB821A4C for ; Sun, 29 Sep 2019 17:35:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569778532; bh=lDQ0vRak90qAKBGgcQOhzIF+hJtm9oHmlBRzBXpF70A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=n7fsNRJRr4jLPFePDZ+HtFEjDWd8bbKxO3dAf2gSZhkYbLRZrTXfS0ougKY4sJ0CU lB6FfhkU2H7cdOcDt98r+yLtofKS59uNit6xfTIoLHdGITuwwGaYC0pE2XegSADwny 3+nopV97+g5FdQNBUSeth1FdJuw3tJiugvxFcxKs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729712AbfI2Rfa (ORCPT ); Sun, 29 Sep 2019 13:35:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:47614 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730596AbfI2Rfa (ORCPT ); Sun, 29 Sep 2019 13:35:30 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6CCB921925; Sun, 29 Sep 2019 17:35:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569778529; bh=lDQ0vRak90qAKBGgcQOhzIF+hJtm9oHmlBRzBXpF70A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PHretzD14Pb8cRSpZpg/8VZhObWYSJdtGiZFwYl7IPxnueSea9y+xfIk/WY+5Y2/0 9cEtGGcQgHFVNxVzuTdghkXHAKF1W3FPmKvSK8UaM0g2yhoFSWGEWmgisfxtrS18Cb 82s/veVUBWfPNh0DMWILqKGJDmtJoYEM6KojRj9E= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: 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 AUTOSEL 4.19 32/33] arm: properly account for stack randomization and stack guard gap Date: Sun, 29 Sep 2019 13:34:20 -0400 Message-Id: <20190929173424.9361-32-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190929173424.9361-1-sashal@kernel.org> References: <20190929173424.9361-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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