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authorAndy Honig <ahonig@google.com>2013-11-18 16:09:22 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-20 07:45:07 -0800
commitf4d838225e0cbdc8099c2eb8d55dd9406def1f33 (patch)
treece82eab11ef8913393eeb58b66e528d2480e78cb /virt/kvm
parenta5633d4871bae973f39945b2ba0f86f6bbd45ab4 (diff)
downloadlinaro-lsk-f4d838225e0cbdc8099c2eb8d55dd9406def1f33.tar.gz
KVM: Improve create VCPU parameter (CVE-2013-4587)
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>
Diffstat (limited to 'virt/kvm')
-rw-r--r--virt/kvm/kvm_main.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 302681c4aa4..eb99458f5b6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1904,6 +1904,9 @@ 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);