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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 DE41BC3F2D7 for ; Tue, 3 Mar 2020 00:02:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B2222217F4 for ; Tue, 3 Mar 2020 00:02:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727103AbgCBX5Y (ORCPT ); Mon, 2 Mar 2020 18:57:24 -0500 Received: from mga02.intel.com ([134.134.136.20]:25519 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727030AbgCBX5Y (ORCPT ); Mon, 2 Mar 2020 18:57:24 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Mar 2020 15:57:22 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,509,1574150400"; d="scan'208";a="243384638" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga006.jf.intel.com with ESMTP; 02 Mar 2020 15:57:21 -0800 From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Xiaoyao Li Subject: [PATCH v2 05/66] KVM: x86: Check userapce CPUID array size after validating sub-leaf Date: Mon, 2 Mar 2020 15:56:08 -0800 Message-Id: <20200302235709.27467-6-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200302235709.27467-1-sean.j.christopherson@intel.com> References: <20200302235709.27467-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Verify that the next sub-leaf of CPUID 0x4 (or 0x8000001d) is valid before rejecting the entire KVM_GET_SUPPORTED_CPUID due to insufficent space in the userspace array. Note, although this is technically a bug, it's not visible to userspace as KVM_GET_SUPPORTED_CPUID is guaranteed to fail on KVM_CPUID_SIGNATURE, which is hardcoded to be added after the affected leafs. The real motivation for the change is to tightly couple the nent/maxnent and do_host_cpuid() sequences in preparation for future cleanup. Reviewed-by: Vitaly Kuznetsov Signed-off-by: Sean Christopherson --- arch/x86/kvm/cpuid.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 11d5f311ef10..e5cf1e0cf84a 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -552,12 +552,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, /* read more entries until cache_type is zero */ for (i = 1; ; ++i) { - if (*nent >= maxnent) - goto out; - cache_type = entry[i - 1].eax & 0x1f; if (!cache_type) break; + + if (*nent >= maxnent) + goto out; do_host_cpuid(&entry[i], function, i); ++*nent; } -- 2.24.1