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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 F2D17CA90AF for ; Wed, 13 May 2020 10:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4E0B206E5 for ; Wed, 13 May 2020 10:29:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XFQh3s3+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728606AbgEMK3D (ORCPT ); Wed, 13 May 2020 06:29:03 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:46021 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727794AbgEMK3C (ORCPT ); Wed, 13 May 2020 06:29:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589365740; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kcmT/ox8AHLX/QMTCJPzRwt3hsJ5CzQByK8qyk+UAh8=; b=XFQh3s3+BqgZf/oeqbAkce3N8p1GHCw+DmgJLAFJuQuxEMESIWpX7MaGiBvuzLIDlmjaeA KL6OWyzRHXYOJiflsuFIvSY59RSvIt42ScTO7u9yLDJmuhhg1DUrppRB23utWs0/mEhti8 yWTm2w4UOuIgdxr3gPX6bpVm7yM09Jc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-283-xqI8SoykMmaPbd2Rkkxylw-1; Wed, 13 May 2020 06:28:59 -0400 X-MC-Unique: xqI8SoykMmaPbd2Rkkxylw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8B59F835B46; Wed, 13 May 2020 10:28:57 +0000 (UTC) Received: from localhost (unknown [10.40.208.69]) by smtp.corp.redhat.com (Postfix) with ESMTP id D57247D94A; Wed, 13 May 2020 10:28:49 +0000 (UTC) Date: Wed, 13 May 2020 12:28:47 +0200 From: Igor Mammedov To: Pan Nengyuan Cc: , , , , euler.robot@huawei.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, zhang.zhanghailiang@huawei.com Subject: Re: [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug Message-ID: <20200513122847.10dbc3c0@redhat.com> In-Reply-To: <20200513132630.13412-1-pannengyuan@huawei.com> References: <20200513132630.13412-1-pannengyuan@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 13 May 2020 09:26:30 -0400 Pan Nengyuan wrote: > When we hotplug vcpus, cpu_update_state is added to vm_change_state_head > in kvm_arch_init_vcpu(). But it forgot to delete in kvm_arch_destroy_vcpu= () after > unplug. Then it will cause a use-after-free access. This patch delete it = in > kvm_arch_destroy_vcpu() to fix that. >=20 > Reproducer: > virsh setvcpus vm1 4 --live > virsh setvcpus vm1 2 --live > virsh suspend vm1 > virsh resume vm1 >=20 > The UAF stack: > =3D=3Dqemu-system-x86_64=3D=3D28233=3D=3DERROR: AddressSanitizer: heap-us= e-after-free on address 0x62e00002e798 at pc 0x5573c6917d9e bp 0x7fff07139e= 50 sp 0x7fff07139e40 > WRITE of size 1 at 0x62e00002e798 thread T0 > #0 0x5573c6917d9d in cpu_update_state /mnt/sdb/qemu/target/i386/kvm.c= :742 > #1 0x5573c699121a in vm_state_notify /mnt/sdb/qemu/vl.c:1290 > #2 0x5573c636287e in vm_prepare_start /mnt/sdb/qemu/cpus.c:2144 > #3 0x5573c6362927 in vm_start /mnt/sdb/qemu/cpus.c:2150 > #4 0x5573c71e8304 in qmp_cont /mnt/sdb/qemu/monitor/qmp-cmds.c:173 > #5 0x5573c727cb1e in qmp_marshal_cont qapi/qapi-commands-misc.c:835 > #6 0x5573c7694c7a in do_qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.= c:132 > #7 0x5573c7694c7a in qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:1= 75 > #8 0x5573c71d9110 in monitor_qmp_dispatch /mnt/sdb/qemu/monitor/qmp.c= :145 > #9 0x5573c71dad4f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu/monitor/= qmp.c:234 >=20 > Reported-by: Euler Robot > Signed-off-by: Pan Nengyuan > Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Igor Mammedov > --- > - v2: remove unnecessary set vmsentry to null(there is no non-null check). > --- > target/i386/cpu.h | 1 + > target/i386/kvm.c | 4 +++- > 2 files changed, 4 insertions(+), 1 deletion(-) >=20 > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index e818fc712a..afbd11b7a3 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -1631,6 +1631,7 @@ struct X86CPU { > =20 > CPUNegativeOffsetState neg; > CPUX86State env; > + VMChangeStateEntry *vmsentry; > =20 > uint64_t ucode_rev; > =20 > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > index 4901c6dd74..0a4eca5a85 100644 > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -1770,7 +1770,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > } > } > =20 > - qemu_add_vm_change_state_handler(cpu_update_state, env); > + cpu->vmsentry =3D qemu_add_vm_change_state_handler(cpu_update_state,= env); > =20 > c =3D cpuid_find_entry(&cpuid_data.cpuid, 1, 0); > if (c) { > @@ -1883,6 +1883,8 @@ int kvm_arch_destroy_vcpu(CPUState *cs) > env->nested_state =3D NULL; > } > =20 > + qemu_del_vm_change_state_handler(cpu->vmsentry); > + > return 0; > } > =20