From patchwork Wed Jan 3 22:31:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Mattson X-Patchwork-Id: 10143611 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A16FE6034B for ; Wed, 3 Jan 2018 22:40:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8E18229369 for ; Wed, 3 Jan 2018 22:40:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 813CF29346; Wed, 3 Jan 2018 22:40:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 196B129346 for ; Wed, 3 Jan 2018 22:40:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751471AbeACWkN (ORCPT ); Wed, 3 Jan 2018 17:40:13 -0500 Received: from mail-it0-f67.google.com ([209.85.214.67]:39675 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbeACWkK (ORCPT ); Wed, 3 Jan 2018 17:40:10 -0500 Received: by mail-it0-f67.google.com with SMTP id 68so274025ite.4 for ; Wed, 03 Jan 2018 14:40:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=U4E7selyEhverjW78RnoJsNzXcmSnHQFL9NkoGscRkQ=; b=ml+Jjy+TIn7vl2H9wUCk19oxRtvJoFmo69eGu1PPDv9Mr0XPtvT++MN9A2D6kA0sYo pCQQWAjEpDYTISjPW6YQgZxPcpTxKY6IiAQxLwzijOkuW+thJ40wwOjyIvHqWyMj0mUQ wAza5kS0ccW56hCTVW6Zorgd5r0OWXEHyWtQa2dUvMlrdYFR/ShVsUGa4OZR2U5hG43n /wqnyu4s2mLXRu2WOSJ8Egu7kA1h94cSQttkjZz6uoAw4dMKn3WYyqthe4oILfK67hpf zmdUAuegC8lFBAQb2s53u/b1UN805K4URfDSNBsoIVSnX+WBq8ZyJ79WBdZS6j3n0Ld6 I3aA== 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=U4E7selyEhverjW78RnoJsNzXcmSnHQFL9NkoGscRkQ=; b=oNNwH6VvkOy1S3D79vFLa5HwgLAVQeUI6C1cTnJKegOehkLi2CRLHDbVq+PRC4mUfl xonK2e2m7DYws3oxR2ggyKkMrQ+bTSXNoZI8LR01GaEW9ruXQ//oT21/Pz2EmMwEKB6Y xzVCG26D2Qr4zucziwp0CjBI/lSvoYuNEBs+Om/SvkEXnEFD6IHRw/IlzON0UupBJdS1 TBldQPt1HE3ZFdYmViBf3jB6sWEkxONLQj6EZYYHwdWWrgR7YyoNZBa1CtCHdnyE3gm4 uRbPSAUR8jZv0WwyHKe6PC5DUf/jQN0CMy6nHtjeKugJJfM3OR7LUZSxVFiqP4UVvKC2 MtJA== X-Gm-Message-State: AKGB3mIyhOFpmNChSZeDdka8gVngN6b8qhQBVCRNd9tBLV03XkAIHvEW uDr3shf5foM7tvaVs033AdAGEBOXKGs= X-Google-Smtp-Source: ACJfBouGNVWMr//SqjJCIZUkERSK5FClUODYL0JNhGO/S9+PXRwF3xCoQdZ6GxOGIMKF3IkVZZS4qw== X-Received: by 10.36.170.14 with SMTP id b14mr3856662itf.13.1515019209418; Wed, 03 Jan 2018 14:40:09 -0800 (PST) Received: from turtle.sea.corp.google.com ([100.100.207.61]) by smtp.gmail.com with ESMTPSA id h94sm1126761iod.40.2018.01.03.14.40.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 03 Jan 2018 14:40:08 -0800 (PST) From: Jim Mattson To: kvm@vger.kernel.org Cc: Jim Mattson Subject: [PATCH] kvm: vmx: Scrub hardware GPRs at VM-exit Date: Wed, 3 Jan 2018 14:31:38 -0800 Message-Id: <20180103223138.102768-1-jmattson@google.com> X-Mailer: git-send-email 2.15.1.620.gb9897f4670-goog Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Guest GPR values are live in the hardware GPRs at VM-exit. Do not leave any guest values in hardware GPRs after the guest GPR values are saved to the vcpu_vmx structure. This is a partial mitigation for CVE 2017-5715 and CVE 2017-5753. Specifically, it defeats the Project Zero PoC for CVE 2017-5715. Suggested-by: Eric Northup Signed-off-by: Jim Mattson Reviewed-by: Eric Northup Reviewed-by: Benjamin Serebrin Reviewed-by: Andrew Honig --- arch/x86/kvm/vmx.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 669f5f74857d..850baff9d107 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -9649,6 +9649,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) /* Save guest registers, load host registers, keep flags */ "mov %0, %c[wordsize](%%" _ASM_SP ") \n\t" "pop %0 \n\t" + "setbe %c[fail](%0)\n\t" "mov %%" _ASM_AX ", %c[rax](%0) \n\t" "mov %%" _ASM_BX ", %c[rbx](%0) \n\t" __ASM_SIZE(pop) " %c[rcx](%0) \n\t" @@ -9665,12 +9666,23 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) "mov %%r13, %c[r13](%0) \n\t" "mov %%r14, %c[r14](%0) \n\t" "mov %%r15, %c[r15](%0) \n\t" + "xor %%r8d, %%r8d \n\t" + "xor %%r9d, %%r9d \n\t" + "xor %%r10d, %%r10d \n\t" + "xor %%r11d, %%r11d \n\t" + "xor %%r12d, %%r12d \n\t" + "xor %%r13d, %%r13d \n\t" + "xor %%r14d, %%r14d \n\t" + "xor %%r15d, %%r15d \n\t" #endif "mov %%cr2, %%" _ASM_AX " \n\t" "mov %%" _ASM_AX ", %c[cr2](%0) \n\t" + "xor %%eax, %%eax \n\t" + "xor %%ebx, %%ebx \n\t" + "xor %%esi, %%esi \n\t" + "xor %%edi, %%edi \n\t" "pop %%" _ASM_BP "; pop %%" _ASM_DX " \n\t" - "setbe %c[fail](%0) \n\t" ".pushsection .rodata \n\t" ".global vmx_return \n\t" "vmx_return: " _ASM_PTR " 2b \n\t"