2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------ There is a bug in KVM that can be used to crash a host on Intel machines. If emulator is tricked into emulating mov to/from DR instruction it causes NULL pointer dereference on VMX since kvm_x86_ops->(set|get)_dr are not initialized. Recently this is not exploitable from guest userspace, but malicious guest kernel can trigger it easily. CVE-2010-0435 On upstream bug was fixed differently around 2.6.34. Signed-off-by: Gleb Natapov <[email protected]> Signed-off-by: Avi Kivity <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kvm/x86.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2782,6 +2782,9 @@ int emulator_get_dr(struct x86_emulate_c { struct kvm_vcpu *vcpu = ctxt->vcpu; + if (!kvm_x86_ops->get_dr) + return X86EMUL_UNHANDLEABLE; + switch (dr) { case 0 ... 3: *dest = kvm_x86_ops->get_dr(vcpu, dr); @@ -2797,6 +2800,9 @@ int emulator_set_dr(struct x86_emulate_c unsigned long mask = (ctxt->mode == X86EMUL_MODE_PROT64) ? ~0ULL : ~0U; int exception; + if (!kvm_x86_ops->set_dr) + return X86EMUL_UNHANDLEABLE; + kvm_x86_ops->set_dr(ctxt->vcpu, dr, value & mask, &exception); if (exception) { /* FIXME: better handling */ _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
