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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 06BE9C4360F for ; Thu, 4 Apr 2019 08:56:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C3F012177E for ; Thu, 4 Apr 2019 08:56:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554368179; bh=sl7L8ILsqxlHfyGIFJaE9lnYYFD9MTdIxzPZvBJ9amo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SlUluxV9UbzyiBIHSm/PD/xwDR4nFxXuNMxzVdjYeQaICKqWZ+5/Pt74ncY/Epl38 KQNIqE4XI8S9wXxr5FkGao+qe3tc4udGzFjrQKh8S093biU/PxFqOxuKId7COmc1Le dmc00c8DCL1ucBULCANmyUxBmSRMJOBMOlhGstiY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730454AbfDDI4S (ORCPT ); Thu, 4 Apr 2019 04:56:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:59468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730436AbfDDI4M (ORCPT ); Thu, 4 Apr 2019 04:56:12 -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 2FCB220693; Thu, 4 Apr 2019 08:56:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554368171; bh=sl7L8ILsqxlHfyGIFJaE9lnYYFD9MTdIxzPZvBJ9amo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VU12lp3uh/kkt4awiEiy581TLq/Mr1bYpsq/cyMlPYxOwotk4YMMcSqfL31TLWeXx 0WBeqW5pOs8oU1tZQTjDIQAuI+o+nafxi0ACMomiBBt5W6Z7hdtA2KWWHNEHZRaLvH YzB24wc03iNd46g8P+iG+kpPTiNPoycgvYIyeS6Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Laurent Dufour , "Aneesh Kumar K.V" , Michael Ellerman , Sasha Levin Subject: [PATCH 4.14 047/121] powerpc/hugetlb: Handle mmap_min_addr correctly in get_unmapped_area callback Date: Thu, 4 Apr 2019 10:47:15 +0200 Message-Id: <20190404084547.818350022@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190404084545.245659903@linuxfoundation.org> References: <20190404084545.245659903@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 5330367fa300742a97e20e953b1f77f48392faae ] After we ALIGN up the address we need to make sure we didn't overflow and resulted in zero address. In that case, we need to make sure that the returned address is greater than mmap_min_addr. This fixes selftest va_128TBswitch --run-hugetlb reporting failures when run as non root user for mmap(-1, MAP_HUGETLB) The bug is that a non-root user requesting address -1 will be given address 0 which will then fail, whereas they should have been given something else that would have succeeded. We also avoid the first mmap(-1, MAP_HUGETLB) returning NULL address as mmap address with this change. So we think this is not a security issue, because it only affects whether we choose an address below mmap_min_addr, not whether we actually allow that address to be mapped. ie. there are existing capability checks to prevent a user mapping below mmap_min_addr and those will still be honoured even without this fix. Fixes: 484837601d4d ("powerpc/mm: Add radix support for hugetlb") Reviewed-by: Laurent Dufour Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- arch/powerpc/mm/hugetlbpage-radix.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c index bd022d16745c..a31bad29b55d 100644 --- a/arch/powerpc/mm/hugetlbpage-radix.c +++ b/arch/powerpc/mm/hugetlbpage-radix.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #include #include +#include #include #include #include @@ -79,7 +80,7 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, if (addr) { addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); - if (high_limit - len >= addr && + if (high_limit - len >= addr && addr >= mmap_min_addr && (!vma || addr + len <= vm_start_gap(vma))) return addr; } @@ -89,7 +90,7 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, */ info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.length = len; - info.low_limit = PAGE_SIZE; + info.low_limit = max(PAGE_SIZE, mmap_min_addr); info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW); info.align_mask = PAGE_MASK & ~huge_page_mask(h); info.align_offset = 0; -- 2.19.1