From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751833AbdITE6A (ORCPT ); Wed, 20 Sep 2017 00:58:00 -0400 Received: from omzsmtpe03.verizonbusiness.com ([199.249.25.208]:56381 "EHLO omzsmtpe03.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748AbdITEqC (ORCPT ); Wed, 20 Sep 2017 00:46:02 -0400 From: "Levin, Alexander (Sasha Levin)" Cc: Oleksandr Tyshchenko , Will Deacon , Robin Murphy , "Levin, Alexander (Sasha Levin)" X-Host: challenger.odc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH review for 4.4 42/47] iommu/io-pgtable-arm: Check for leaf entry before dereferencing it Thread-Topic: [PATCH review for 4.4 42/47] iommu/io-pgtable-arm: Check for leaf entry before dereferencing it Thread-Index: AQHTMcs9YJIIS57RjECzqTvAokCYrw== Date: Wed, 20 Sep 2017 04:45:10 +0000 Message-ID: <20170920044445.7392-42-alexander.levin@verizon.com> References: <20170920044445.7392-1-alexander.levin@verizon.com> In-Reply-To: <20170920044445.7392-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8K4w8hA025115 From: Oleksandr Tyshchenko [ Upstream commit ed46e66cc1b3d684042f92dfa2ab15ee917b4cac ] Do a check for already installed leaf entry at the current level before dereferencing it in order to avoid walking the page table down with wrong pointer to the next level. Signed-off-by: Oleksandr Tyshchenko CC: Will Deacon CC: Robin Murphy Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/iommu/io-pgtable-arm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index dad768caa9c5..18751b1dfd3d 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -335,8 +335,12 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova, if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS) pte |= ARM_LPAE_PTE_NSTABLE; __arm_lpae_set_pte(ptep, pte, cfg); - } else { + } else if (!iopte_leaf(pte, lvl)) { cptep = iopte_deref(pte, data); + } else { + /* We require an unmap first */ + WARN_ON(!selftest_running); + return -EEXIST; } /* Rinse, repeat */ -- 2.11.0