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=unavailable 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 E912AC4360F for ; Thu, 4 Apr 2019 09:28:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B302820820 for ; Thu, 4 Apr 2019 09:28:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554370099; bh=4ZHzu6Nj+eNcUD3b8X7xVuToNRpq6124yjPBYt2rJjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uxPqBkBXS3Bo47vSFWH2fTv2Qbr9jQVVO7tpQs7EkLIoL2KwsnyAiLd5o/2AOqqTX 38VHDqG8TpQLDM59L93WqJaycFayUWEI2AmyvfWaF5LHtyZ6wmt3CoRZFHlykMiqS9 +6Y8ckCDNGt/kS52nVaeBFEx/NtOtxoPBNykoKhM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733044AbfDDJL6 (ORCPT ); Thu, 4 Apr 2019 05:11:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:51880 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733030AbfDDJL5 (ORCPT ); Thu, 4 Apr 2019 05:11:57 -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 40EE32054F; Thu, 4 Apr 2019 09:11:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554369116; bh=4ZHzu6Nj+eNcUD3b8X7xVuToNRpq6124yjPBYt2rJjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NwykczK2eONtSH7JDdp8vXGEOrme1dqkJbUPPVYh58Rxm7MY71Oz1wr3ca8a17ts5 6qRjgZVd2nKFqS0jlxszdTOKBXXTmjTwiQqn4q/PC9SUNzTYoq6GSf2HVAckd64l8p DY8j20F79L8LTWckyr26A/WJ/wmIQwQ6RuKplfvw= 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 5.0 080/246] powerpc/hugetlb: Handle mmap_min_addr correctly in get_unmapped_area callback Date: Thu, 4 Apr 2019 10:46:20 +0200 Message-Id: <20190404084621.935017873@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190404084619.236418459@linuxfoundation.org> References: <20190404084619.236418459@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.0-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 2486bee0f93e..97c7a39ebc00 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 @@ -73,7 +74,7 @@ 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; } @@ -83,7 +84,7 @@ 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