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 D9AC7C433DF for ; Tue, 9 Jun 2020 17:47:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6DAF20814 for ; Tue, 9 Jun 2020 17:47:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591724877; bh=o0z1CX9zgBwNi/5coVAOQuBt/Vh7tSaDqWRWGlBBG8k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SFI6U7qDIrdpbTMUTYm/uBobF80RLmSKXxVQAp/FQ40pMJTFTJQsImJPx5HX/VIqH geKD6MH9MB3QfS6rnzR3bAl03uzRRBhUb1vhxxGR+aNTm0VWKAlfx5gYc19SR6wzwj yTj7qdei0LFuvJ3aiUHi9Q+OCAvIyV00ShfZ6viI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730677AbgFIRrz (ORCPT ); Tue, 9 Jun 2020 13:47:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:59228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732151AbgFIRrq (ORCPT ); Tue, 9 Jun 2020 13:47:46 -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 D3E4C2081A; Tue, 9 Jun 2020 17:47:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591724865; bh=o0z1CX9zgBwNi/5coVAOQuBt/Vh7tSaDqWRWGlBBG8k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S4yhKmdiu2tTBRNqsFc/dJshcKPfFIDEzW5mRQnCUadY0I1I+F28XPyA1ojAdMC3U TjQfx/oh/0sFbO+H+Y40KYQL8/2SPefxpN32ThZOMFnfzCJj0nM1LSRNxInIPe/TBo 0aBYspFixYMotTRN3jdeXgNUPdlF39vu2d6hu2yo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Fan Yang , Dan Williams , "Kirill A. Shutemov" , Linus Torvalds Subject: [PATCH 4.9 13/42] mm: Fix mremap not considering huge pmd devmap Date: Tue, 9 Jun 2020 19:44:19 +0200 Message-Id: <20200609174016.911176319@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200609174015.379493548@linuxfoundation.org> References: <20200609174015.379493548@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: Fan Yang commit 5bfea2d9b17f1034a68147a8b03b9789af5700f9 upstream. The original code in mm/mremap.c checks huge pmd by: if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) { However, a DAX mapped nvdimm is mapped as huge page (by default) but it is not transparent huge page (_PAGE_PSE | PAGE_DEVMAP). This commit changes the condition to include the case. This addresses CVE-2020-10757. Fixes: 5c7fb56e5e3f ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd") Cc: Reported-by: Fan Yang Signed-off-by: Fan Yang Tested-by: Fan Yang Tested-by: Dan Williams Reviewed-by: Dan Williams Acked-by: Kirill A. Shutemov Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/pgtable.h | 1 + mm/mremap.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -203,6 +203,7 @@ static inline int pmd_large(pmd_t pte) } #ifdef CONFIG_TRANSPARENT_HUGEPAGE +/* NOTE: when predicate huge page, consider also pmd_devmap, or use pmd_large */ static inline int pmd_trans_huge(pmd_t pmd) { return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE; --- a/mm/mremap.c +++ b/mm/mremap.c @@ -212,7 +212,7 @@ unsigned long move_page_tables(struct vm new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr); if (!new_pmd) break; - if (pmd_trans_huge(*old_pmd)) { + if (pmd_trans_huge(*old_pmd) || pmd_devmap(*old_pmd)) { if (extent == HPAGE_PMD_SIZE) { bool moved; /* See comment in move_ptes() */