| From | Ben Hutchings <> | Date | Sun, 29 Dec 2013 03:08:44 +0100 | Subject | [PATCH 3.2 142/185] KVM: Improve create VCPU parameter (CVE-2013-4587) |
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3.2.54-rc1 review patch. If anyone has any objections, please let me know.
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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: Ben Hutchings <ben@decadent.org.uk> --- virt/kvm/kvm_main.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1683,6 +1683,9 @@ 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);
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