From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932263Ab3LQSQB (ORCPT ); Tue, 17 Dec 2013 13:16:01 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:32955 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932227Ab3LQSP5 (ORCPT ); Tue, 17 Dec 2013 13:15:57 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andrew Honig , Paolo Bonzini , Luis Henriques Subject: [PATCH 3.5 096/103] KVM: Improve create VCPU parameter (CVE-2013-4587) Date: Tue, 17 Dec 2013 18:13:25 +0000 Message-Id: <1387304012-23805-97-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1387304012-23805-1-git-send-email-luis.henriques@canonical.com> References: <1387304012-23805-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.28 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Honig commit 338c7dbadd2671189cec7faf64c84d01071b3f96 upstream. In multiple functions the vcpu_id is used as an offset into a bitfield. Ag malicious user could specify a vcpu_id greater than 255 in order to set or clear bits in kernel memory. This could be used to elevate priveges in the kernel. This patch verifies that the vcpu_id provided is less than 255. The api documentation already specifies that the vcpu_id must be less than max_vcpus, but this is currently not checked. Reported-by: Andrew Honig Signed-off-by: Andrew Honig Signed-off-by: Paolo Bonzini Signed-off-by: Luis Henriques --- virt/kvm/kvm_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 1b29357..6c6631a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1698,6 +1698,9 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) int r; struct kvm_vcpu *vcpu, *v; + if (id >= KVM_MAX_VCPUS) + return -EINVAL; + vcpu = kvm_arch_vcpu_create(kvm, id); if (IS_ERR(vcpu)) return PTR_ERR(vcpu); -- 1.8.3.2