| From 338c7dbadd2671189cec7faf64c84d01071b3f96 Mon Sep 17 00:00:00 2001 |
| From: Andy Honig <ahonig@google.com> |
| Date: Mon, 18 Nov 2013 16:09:22 -0800 |
| Subject: KVM: Improve create VCPU parameter (CVE-2013-4587) |
| |
| From: Andy Honig <ahonig@google.com> |
| |
| 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 <ahonig@google.com> |
| Signed-off-by: Andrew Honig <ahonig@google.com> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| virt/kvm/kvm_main.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/virt/kvm/kvm_main.c |
| +++ b/virt/kvm/kvm_main.c |
| @@ -1893,6 +1893,9 @@ static int kvm_vm_ioctl_create_vcpu(stru |
| 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); |
