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Date: Wed, 3 Sep 2014 15:05:14 -0700 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Nadav Amit <namit@...technion.ac.il>, Paolo Bonzini <pbonzini@...hat.com> Subject: [PATCH 3.14 40/88] KVM: x86: Inter-privilege level ret emulation is not implemeneted 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nadav Amit <namit@...technion.ac.il> commit 9e8919ae793f4edfaa29694a70f71a515ae9942a upstream. Return unhandlable error on inter-privilege level ret instruction. This is since the current emulation does not check the privilege level correctly when loading the CS, and does not pop RSP/SS as needed. Signed-off-by: Nadav Amit <namit@...technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- arch/x86/kvm/emulate.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2006,6 +2006,7 @@ static int em_ret_far(struct x86_emulate { int rc; unsigned long cs; + int cpl = ctxt->ops->cpl(ctxt); rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes); if (rc != X86EMUL_CONTINUE) @@ -2015,6 +2016,9 @@ static int em_ret_far(struct x86_emulate rc = emulate_pop(ctxt, &cs, ctxt->op_bytes); if (rc != X86EMUL_CONTINUE) return rc; + /* Outer-privilege level return is not implemented */ + if (ctxt->mode >= X86EMUL_MODE_PROT16 && (cs & 3) > cpl) + return X86EMUL_UNHANDLEABLE; rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS); return rc; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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