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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 682B9C606C1 for ; Mon, 8 Jul 2019 15:23:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41329214C6 for ; Mon, 8 Jul 2019 15:23:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562599394; bh=N+UVgD7OA5w7i4Zf1c+vj6sMbNBUCNtULkD6pkUw0ws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0Y83Pcsq6eXj0GMquAXkAg2VqZYf2T1DU82SoqWji/lsuyBNF7hI303MctzHZ7jrC gJ0NiEf4nvsf7tLLKoBddjT4Ac5M5Sf9HRQ/myVPTSd7ewDGiwNDlxFOTiKCeN6E+L EjD8eoHfwlIJBzhkl6qQbqgLEoEQWf25cNcYyljM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388154AbfGHPXM (ORCPT ); Mon, 8 Jul 2019 11:23:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:50044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388134AbfGHPXJ (ORCPT ); Mon, 8 Jul 2019 11:23:09 -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 D958E204EC; Mon, 8 Jul 2019 15:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562599388; bh=N+UVgD7OA5w7i4Zf1c+vj6sMbNBUCNtULkD6pkUw0ws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xojPNPSwViqvhqS/AWJkLO6l7Lr3/qj1C5vtEDrBcm0LUp2pv9r0gLx5hhZQ/CmC5 GRFDeIvWk4MmIUKvfnHsO+g68cXaWvZ/iUP30NzP/7zg8EWaVG4Tzmup/IeOUSDPsd E6GXmehiLDzU/K1sSkzPBjyL+50s7tywWO143HPQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , Ard Biesheuvel , Will Deacon Subject: [PATCH 4.9 102/102] arm64: kaslr: keep modules inside module region when KASAN is enabled Date: Mon, 8 Jul 2019 17:13:35 +0200 Message-Id: <20190708150531.760421168@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190708150525.973820964@linuxfoundation.org> References: <20190708150525.973820964@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: Ard Biesheuvel commit 6f496a555d93db7a11d4860b9220d904822f586a upstream. When KASLR and KASAN are both enabled, we keep the modules where they are, and randomize the placement of the kernel so it is within 2 GB of the module region. The reason for this is that putting modules in the vmalloc region (like we normally do when KASLR is enabled) is not possible in this case, given that the entire vmalloc region is already backed by KASAN zero shadow pages, and so allocating dedicated KASAN shadow space as required by loaded modules is not possible. The default module allocation window is set to [_etext - 128MB, _etext] in kaslr.c, which is appropriate for KASLR kernels booted without a seed or with 'nokaslr' on the command line. However, as it turns out, it is not quite correct for the KASAN case, since it still intersects the vmalloc region at the top, where attempts to allocate shadow pages will collide with the KASAN zero shadow pages, causing a WARN() and all kinds of other trouble. So cap the top end to MODULES_END explicitly when running with KASAN. Cc: # 4.9+ Acked-by: Catalin Marinas Tested-by: Catalin Marinas Signed-off-by: Ard Biesheuvel [will: backport to 4.9.y] Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/module.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -33,10 +33,14 @@ void *module_alloc(unsigned long size) { void *p; + u64 module_alloc_end = module_alloc_base + MODULES_VSIZE; + + if (IS_ENABLED(CONFIG_KASAN)) + /* don't exceed the static module region - see below */ + module_alloc_end = MODULES_END; p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base, - module_alloc_base + MODULES_VSIZE, - GFP_KERNEL, PAGE_KERNEL_EXEC, 0, + module_alloc_end, GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, __builtin_return_address(0)); if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&