From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andrew Honig , Paolo Bonzini , Kamal Mostafa Subject: [PATCH 3.8 051/166] KVM: Improve create VCPU parameter (CVE-2013-4587) Date: Wed, 15 Jan 2014 13:51:05 -0800 Message-Id: <1389822780-4729-52-git-send-email-kamal@canonical.com> In-Reply-To: <1389822780-4729-1-git-send-email-kamal@canonical.com> References: <1389822780-4729-1-git-send-email-kamal@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8.13.16 -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: Kamal Mostafa --- 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 4dc41654..4884600 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1839,6 +1839,9 @@ 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