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,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 1939DC47257 for ; Mon, 4 May 2020 18:15:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF56520705 for ; Mon, 4 May 2020 18:15:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588616118; bh=6Rv8g7Pik3o5TY+Aa2mrVyiSSrcmj02o9OfxZPNwV/A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aRshSd2D4oaowqKvEqFAiSgSZbFPsSLyqZTQYI2mYBCEusxV7bELvch5GGyanotJY z2pkL6MDkBmrva7FWAy1KfYZQcWH7QQWy5C0KZ+5O+HqayJ32tfI247Dpy3ZfXlhql fdVcMfkQMmNrmNjvyfa3x/UnkbgdHMJ0syVexvsg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730815AbgEDR7d (ORCPT ); Mon, 4 May 2020 13:59:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:53118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730794AbgEDR73 (ORCPT ); Mon, 4 May 2020 13:59:29 -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 4FB0820746; Mon, 4 May 2020 17:59:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615167; bh=6Rv8g7Pik3o5TY+Aa2mrVyiSSrcmj02o9OfxZPNwV/A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gkL70LFyQIzAzxDLQhcxeUK9isBGoXP+38Uns2NyA/SSHbd3xDO1V+7mfhFN6ULMn EdEW5zzWy/KtIo5dva7S14gVOnjRaNC4RNgFTndHUDyikgD5Ha58E/uwDdPzLBydyU K+6Lcd3ZEANl0uZCYhmJvDtVpCo/goWfrmJWO5aM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Alex Williamson Subject: [PATCH 4.9 12/18] vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn() Date: Mon, 4 May 2020 19:57:22 +0200 Message-Id: <20200504165444.661937255@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200504165442.028485341@linuxfoundation.org> References: <20200504165442.028485341@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: Sean Christopherson commit 5cbf3264bc715e9eb384e2b68601f8c02bb9a61d upstream. Use follow_pfn() to get the PFN of a PFNMAP VMA instead of assuming that vma->vm_pgoff holds the base PFN of the VMA. This fixes a bug where attempting to do VFIO_IOMMU_MAP_DMA on an arbitrary PFNMAP'd region of memory calculates garbage for the PFN. Hilariously, this only got detected because the first "PFN" calculated by vaddr_get_pfn() is PFN 0 (vma->vm_pgoff==0), and iommu_iova_to_phys() uses PA==0 as an error, which triggers a WARN in vfio_unmap_unpin() because the translation "failed". PFN 0 is now unconditionally reserved on x86 in order to mitigate L1TF, which causes is_invalid_reserved_pfn() to return true and in turns results in vaddr_get_pfn() returning success for PFN 0. Eventually the bogus calculation runs into PFNs that aren't reserved and leads to failure in vfio_pin_map_dma(). The subsequent call to vfio_remove_dma() attempts to unmap PFN 0 and WARNs. WARNING: CPU: 8 PID: 5130 at drivers/vfio/vfio_iommu_type1.c:750 vfio_unmap_unpin+0x2e1/0x310 [vfio_iommu_type1] Modules linked in: vfio_pci vfio_virqfd vfio_iommu_type1 vfio ... CPU: 8 PID: 5130 Comm: sgx Tainted: G W 5.6.0-rc5-705d787c7fee-vfio+ #3 Hardware name: Intel Corporation Mehlow UP Server Platform/Moss Beach Server, BIOS CNLSE2R1.D00.X119.B49.1803010910 03/01/2018 RIP: 0010:vfio_unmap_unpin+0x2e1/0x310 [vfio_iommu_type1] Code: <0f> 0b 49 81 c5 00 10 00 00 e9 c5 fe ff ff bb 00 10 00 00 e9 3d fe RSP: 0018:ffffbeb5039ebda8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff9a55cbf8d480 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9a52b771c200 RBP: 0000000000000000 R08: 0000000000000040 R09: 00000000fffffff2 R10: 0000000000000001 R11: ffff9a51fa896000 R12: 0000000184010000 R13: 0000000184000000 R14: 0000000000010000 R15: ffff9a55cb66ea08 FS: 00007f15d3830b40(0000) GS:ffff9a55d5600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561cf39429e0 CR3: 000000084f75f005 CR4: 00000000003626e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vfio_remove_dma+0x17/0x70 [vfio_iommu_type1] vfio_iommu_type1_ioctl+0x9e3/0xa7b [vfio_iommu_type1] ksys_ioctl+0x92/0xb0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x4c/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f15d04c75d7 Code: <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 f7 d8 64 89 01 48 Fixes: 73fa0d10d077 ("vfio: Type1 IOMMU implementation") Signed-off-by: Sean Christopherson Signed-off-by: Alex Williamson Signed-off-by: Greg Kroah-Hartman --- drivers/vfio/vfio_iommu_type1.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -229,8 +229,8 @@ static int vaddr_get_pfn(unsigned long v vma = find_vma_intersection(current->mm, vaddr, vaddr + 1); if (vma && vma->vm_flags & VM_PFNMAP) { - *pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; - if (is_invalid_reserved_pfn(*pfn)) + if (!follow_pfn(vma, vaddr, pfn) && + is_invalid_reserved_pfn(*pfn)) ret = 0; }