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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 7449EC3A5A2 for ; Fri, 23 Aug 2019 07:19:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DF6622CF7 for ; Fri, 23 Aug 2019 07:19:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390134AbfHWHTP (ORCPT ); Fri, 23 Aug 2019 03:19:15 -0400 Received: from mga18.intel.com ([134.134.136.126]:55023 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389165AbfHWHTN (ORCPT ); Fri, 23 Aug 2019 03:19:13 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Aug 2019 00:19:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,420,1559545200"; d="scan'208";a="180619584" Received: from allen-box.sh.intel.com ([10.239.159.136]) by fmsmga007.fm.intel.com with ESMTP; 23 Aug 2019 00:19:09 -0700 From: Lu Baolu To: David Woodhouse , Joerg Roedel , Bjorn Helgaas , Christoph Hellwig Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com, kevin.tian@intel.com, mika.westerberg@linux.intel.com, Ingo Molnar , Greg Kroah-Hartman , pengfei.xu@intel.com, Konrad Rzeszutek Wilk , Marek Szyprowski , Robin Murphy , Jonathan Corbet , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Steven Rostedt , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v7 4/7] swiotlb: Zero out bounce buffer for untrusted device Date: Fri, 23 Aug 2019 15:17:32 +0800 Message-Id: <20190823071735.30264-5-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190823071735.30264-1-baolu.lu@linux.intel.com> References: <20190823071735.30264-1-baolu.lu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is necessary to avoid exposing valid kernel data to any malicious device. Suggested-by: Christoph Hellwig Signed-off-by: Lu Baolu --- kernel/dma/swiotlb.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 89066efa3840..04bea5a87462 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -35,6 +35,7 @@ #include #include #include +#include #ifdef CONFIG_DEBUG_FS #include #endif @@ -458,6 +459,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, unsigned long offset_slots; unsigned long max_slots; unsigned long tmp_io_tlb_used; + void *zero_addr; + size_t zero_size; if (no_iotlb_memory) panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer"); @@ -565,9 +568,20 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, */ for (i = 0; i < nslots; i++) io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT); + + zero_addr = phys_to_virt(tlb_addr); + zero_size = alloc_size; + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && - (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) + (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) { swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE); + zero_addr += mapping_size; + zero_size -= mapping_size; + } + + /* Zero out the bounce buffer if the consumer is untrusted. */ + if (dev_is_untrusted(hwdev) && zero_size) + memset(zero_addr, 0, zero_size); return tlb_addr; } -- 2.17.1