From bd31a7f55777a46063ebe3d50e6536cfff51a757 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Thu, 14 Feb 2013 19:46:27 +0100 Subject: [PATCH] KVM: nVMX: Trap unconditionally if msr bitmap access fails This avoids basing decisions on uninitialized variables, potentially leaking kernel data to the L1 guest. Reviewed-by: Gleb Natapov Signed-off-by: Jan Kiszka Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/vmx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index b4ce43c82748..c1b3041a1f86 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5985,7 +5985,8 @@ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu, /* Then read the msr_index'th bit from this bitmap: */ if (msr_index < 1024*8) { unsigned char b; - kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1); + if (kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1)) + return 1; return 1 & (b >> (msr_index & 7)); } else return 1; /* let L1 handle the wrong parameter */ -- 2.39.5