From: Andy Honig Date: Tue, 19 Nov 2013 00:09:22 +0000 (-0800) Subject: KVM: Improve create VCPU parameter (CVE-2013-4587) X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=338c7dbadd2671189cec7faf64c84d01071b3f96;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git KVM: Improve create VCPU parameter (CVE-2013-4587) 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 Cc: stable@vger.kernel.org Signed-off-by: Andrew Honig Signed-off-by: Paolo Bonzini --- diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a0aa84b5941a..4f588bc94186 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1898,6 +1898,9 @@ 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);