| From | 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 |
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3.8.13.16 -stable 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: Kamal Mostafa <kamal@canonical.com> --- 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
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