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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 5E091C4CECE for ; Tue, 17 Sep 2019 08:16:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 343DD21670 for ; Tue, 17 Sep 2019 08:16:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XMfUu4yb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731034AbfIQIQe (ORCPT ); Tue, 17 Sep 2019 04:16:34 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:40142 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725798AbfIQIQe (ORCPT ); Tue, 17 Sep 2019 04:16:34 -0400 Received: by mail-pl1-f195.google.com with SMTP id d22so1178444pll.7; Tue, 17 Sep 2019 01:16:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=lZpOV5nkYn4l+QDXD4wMM0QQ6pVGsg20H5ZmBWn5rFY=; b=XMfUu4ybyUbjaSQkc+G9xwv+FR7+SYPvEL9Au1fqvVxr5h+D75ZPor60PYddm3kRFN Nl17VEv+RnGNOjmQGn2murgOaEzjIqEAPfvyQIwJLfb7UKfl75QEET7wnkAsxhXl5reZ 0dcBq4BSZBzBOm5xAZkv4cPm+qZBbc3G2f0zm/g4NCObOOIZTXCeHOaTXEkdY2twPdKb gagOsiBm0jYDskJ59NLZDdbeq/ZzDedazC90wFT+oFEHxo8V0cj3zwm7jD4GYXChgCB3 flHvSawC/l/Qv9DvXaRm0Prx4z/qvrA5CZwTO3amxCGo/fekS2MpplfH1kyQAo2HL0g+ YeHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=lZpOV5nkYn4l+QDXD4wMM0QQ6pVGsg20H5ZmBWn5rFY=; b=ccy85uHNQ/ZSrKqkJKMCGBj22fUjnqHUiT7Rz9SEqDtN3EZJEpBfBM58dmNMkp8YKF a10ATPiRQ5hU6juW6pAqBjTdNrtEzTysagWwd6eL3pySN/Qh9Bf8ADoFWMvcpAYhsH2E gEmBt4bpCq4ymVJH5vt5PBoQwRboHMBu6/XrZ99OAB8oxlN1okPvh+9jp8WJPkxIy9PA svjUmAFrVyinz6eKKMbX53BB1lu81ubimKP78BCTLSaRBHs4tO5IaENkvRiDDDoB2Srw pJrSokpGuTnIkRq3oYweePdwTLoUoyBzDpBItXGos0cR2F4VO9UvjXdhFNuPH8kjCVkG zY8Q== X-Gm-Message-State: APjAAAXARhfHbawggQW+8foBaVNlf/5ZYu3GntSipnffpR0QU+66+jbR IhX7xaOzKxWEFhgm7SHrnXQY577p X-Google-Smtp-Source: APXvYqzNMalAy4NbEJMNfObcCqA9c0UoX5pztAHwrAbtwPMPP4mPFTKD26DkYq65IQVyqtWa82QGOQ== X-Received: by 2002:a17:902:8546:: with SMTP id d6mr2429121plo.170.1568708193274; Tue, 17 Sep 2019 01:16:33 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.123]) by smtp.googlemail.com with ESMTPSA id j10sm1924142pfh.137.2019.09.17.01.16.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 17 Sep 2019 01:16:32 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , stable@vger.kernel.org Subject: [PATCH 1/3] KVM: Fix coalesced mmio ring buffer out-of-bounds access Date: Tue, 17 Sep 2019 16:16:24 +0800 Message-Id: <1568708186-20260-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li Reported by syzkaller: #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 403c01067 P4D 403c01067 PUD 0 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 12564 Comm: a.out Tainted: G OE 5.3.0-rc4+ #4 RIP: 0010:coalesced_mmio_write+0xcc/0x130 [kvm] Call Trace: __kvm_io_bus_write+0x91/0xe0 [kvm] kvm_io_bus_write+0x79/0xf0 [kvm] write_mmio+0xae/0x170 [kvm] emulator_read_write_onepage+0x252/0x430 [kvm] emulator_read_write+0xcd/0x180 [kvm] emulator_write_emulated+0x15/0x20 [kvm] segmented_write+0x59/0x80 [kvm] writeback+0x113/0x250 [kvm] x86_emulate_insn+0x78c/0xd80 [kvm] x86_emulate_instruction+0x386/0x7c0 [kvm] kvm_mmu_page_fault+0xf9/0x9e0 [kvm] handle_ept_violation+0x10a/0x220 [kvm_intel] vmx_handle_exit+0xbe/0x6b0 [kvm_intel] vcpu_enter_guest+0x4dc/0x18d0 [kvm] kvm_arch_vcpu_ioctl_run+0x407/0x660 [kvm] kvm_vcpu_ioctl+0x3ad/0x690 [kvm] do_vfs_ioctl+0xa2/0x690 ksys_ioctl+0x6d/0x80 __x64_sys_ioctl+0x1a/0x20 do_syscall_64+0x74/0x720 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0010:coalesced_mmio_write+0xcc/0x130 [kvm] Both the coalesced_mmio ring buffer indexs ring->first and ring->last are bigger than KVM_COALESCED_MMIO_MAX from the testcase, array out-of-bounds access triggers by ring->coalesced_mmio[ring->last].phys_addr = addr; assignment. This patch fixes it by mod indexs by KVM_COALESCED_MMIO_MAX. syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=134b2826a00000 Reported-by: syzbot+983c866c3dd6efa3662a@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Wanpeng Li --- virt/kvm/coalesced_mmio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c index 5294abb..cff1ec9 100644 --- a/virt/kvm/coalesced_mmio.c +++ b/virt/kvm/coalesced_mmio.c @@ -73,6 +73,8 @@ static int coalesced_mmio_write(struct kvm_vcpu *vcpu, spin_lock(&dev->kvm->ring_lock); + ring->first = ring->first % KVM_COALESCED_MMIO_MAX; + ring->last = ring->last % KVM_COALESCED_MMIO_MAX; if (!coalesced_mmio_has_room(dev)) { spin_unlock(&dev->kvm->ring_lock); return -EOPNOTSUPP; -- 2.7.4