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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB136C433FE for ; Wed, 1 Jun 2022 08:39:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350905AbiFAIjW (ORCPT ); Wed, 1 Jun 2022 04:39:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350904AbiFAIjR (ORCPT ); Wed, 1 Jun 2022 04:39:17 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 11CA45BD05 for ; Wed, 1 Jun 2022 01:39:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1654072754; 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: in-reply-to:in-reply-to:references:references; bh=QtIf3KbY9OaafutQhHCVWaTK0LuvjzCiWKGIzW1Y3vY=; b=UjJUulTZm8o21zv/0is5KT/XgBXiiMJWv/PY4oq76y6eF8FDZCL0YoiRkDM7sUP5fMGsS1 t1vToAxtTKOltm8PuIE7ojmzrPhcfVqjx8BeJOsKKrMfc7k4DB2NNVnaT98V1LVHjcriXd 0qdvEvw4w+gfr4H1LX7oomtHNgg+ZSg= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-178-hu3USXtOPIqwPKRfxQLu2w-1; Wed, 01 Jun 2022 04:39:13 -0400 X-MC-Unique: hu3USXtOPIqwPKRfxQLu2w-1 Received: by mail-ed1-f70.google.com with SMTP id g7-20020a056402424700b0042dee9d11d0so777256edb.3 for ; Wed, 01 Jun 2022 01:39:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=QtIf3KbY9OaafutQhHCVWaTK0LuvjzCiWKGIzW1Y3vY=; b=tKHL6ExQIqzDNj7JEv6c52MnikQ5dKGRGIsXd74hVK1MrYGu1+RnlJlTzjlnkzMG9g CbdWh43rL5dyvnyByyqGrQB8Xwa02c2u5ccs7YNZgJ+DzBrKRsEmtB/ImuML5fE859pu ZhfT3PPo4P20+2hAuRKCn4Zu6Gmc71xPb+6/eLagvnXyd1DVUlgaAr/NuzyF+UAGmSQ/ +0CH1mi+q1DzewUNORH6EX3+z4IF0lwWWRobjZb/B2NfoN0GJGUcJFjx5EPEogDeELVi uIIwYrfm/CuwfDrw7YKE6/8UlcrnehuL8/DJu7pajsq/i0SxJCD4yuSoC2Fj25wSza8N yt/w== X-Gm-Message-State: AOAM53011/GsorO6PBafyQW6dtpdk4j3LshmRhUkgFRSXX4zy2tcEl2K R7uWssbOqTkDruRs7nYG8KAjxTaQCDItwf7IIBd17aDXjqdZZwHL/91FwIa8OhMOqRwgaI4Cp0o uNVUeIe1sko2llJjRyKUzaodh X-Received: by 2002:a17:907:8a01:b0:6ff:3eab:9dfa with SMTP id sc1-20020a1709078a0100b006ff3eab9dfamr20580693ejc.467.1654072752020; Wed, 01 Jun 2022 01:39:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyjUDvptsflZlmEnATV7LNhRKIXP6t0S1OgAvGO5fU2wwcWAFOoBLNlq3tKHCuMQEw6dGIqkA== X-Received: by 2002:a17:907:8a01:b0:6ff:3eab:9dfa with SMTP id sc1-20020a1709078a0100b006ff3eab9dfamr20580681ejc.467.1654072751795; Wed, 01 Jun 2022 01:39:11 -0700 (PDT) Received: from fedora (nat-2.ign.cz. [91.219.240.2]) by smtp.gmail.com with ESMTPSA id cq16-20020a056402221000b0042dd022787esm594062edb.6.2022.06.01.01.39.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Jun 2022 01:39:11 -0700 (PDT) From: Vitaly Kuznetsov To: Sean Christopherson Cc: Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook , Robert Dinse , Paolo Bonzini Subject: Re: [PATCH v2 8/8] KVM: x86: Bug the VM on an out-of-bounds data read In-Reply-To: <20220526210817.3428868-9-seanjc@google.com> References: <20220526210817.3428868-1-seanjc@google.com> <20220526210817.3428868-9-seanjc@google.com> Date: Wed, 01 Jun 2022 10:39:10 +0200 Message-ID: <87ilpkok0h.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sean Christopherson writes: > Bug the VM and terminate emulation if an out-of-bounds read into the > emulator's data cache occurs. Knowingly contuining on all but guarantees > that KVM will overwrite random kernel data, which is far, far worse than > killing the VM. > > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/emulate.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 2aa17462a9ac..39ea9138224c 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -1373,7 +1373,8 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt, > if (mc->pos < mc->end) > goto read_cached; > > - WARN_ON((mc->end + size) >= sizeof(mc->data)); > + if (KVM_EMULATOR_BUG_ON((mc->end + size) >= sizeof(mc->data), ctxt)) > + return X86EMUL_UNHANDLEABLE; > > rc = ctxt->ops->read_emulated(ctxt, addr, mc->data + mc->end, size, > &ctxt->exception); The last WARN_ON() is gone, cool) Reviewed-by: Vitaly Kuznetsov -- Vitaly