From: Marios Pomonis <pomonis@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
rkrcmar@redhat.com,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, Nick Finco <nifi@google.com>,
Andrew Honig <ahonig@google.com>,
Marios Pomonis <pomonis@google.com>,
stable@vger.kernel.org
Subject: [PATCH v2 11/13] KVM: x86: Protect exit_reason from being used in Spectre-v1/L1TF attacks
Date: Wed, 11 Dec 2019 12:47:51 -0800 [thread overview]
Message-ID: <20191211204753.242298-12-pomonis@google.com> (raw)
In-Reply-To: <20191211204753.242298-1-pomonis@google.com>
This fixes a Spectre-v1/L1TF vulnerability in vmx_handle_exit().
While exit_reason is set by the hardware and therefore should not be
attacker-influenced, an unknown exit_reason could potentially be used to
perform such an attack.
Fixes: commit 55d2375e58a6 ("KVM: nVMX: Move nested code to dedicated files")
Signed-off-by: Marios Pomonis <pomonis@google.com>
Signed-off-by: Nick Finco <nifi@google.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
---
arch/x86/kvm/vmx/vmx.c | 55 +++++++++++++++++++++++-------------------
1 file changed, 30 insertions(+), 25 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 82b25f1812aa..78f2fef97d93 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5918,34 +5918,39 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
}
}
- if (exit_reason < kvm_vmx_max_exit_handlers
- && kvm_vmx_exit_handlers[exit_reason]) {
+ if (exit_reason >= kvm_vmx_max_exit_handlers)
+ goto unexpected_vmexit;
#ifdef CONFIG_RETPOLINE
- if (exit_reason == EXIT_REASON_MSR_WRITE)
- return kvm_emulate_wrmsr(vcpu);
- else if (exit_reason == EXIT_REASON_PREEMPTION_TIMER)
- return handle_preemption_timer(vcpu);
- else if (exit_reason == EXIT_REASON_PENDING_INTERRUPT)
- return handle_interrupt_window(vcpu);
- else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
- return handle_external_interrupt(vcpu);
- else if (exit_reason == EXIT_REASON_HLT)
- return kvm_emulate_halt(vcpu);
- else if (exit_reason == EXIT_REASON_EPT_MISCONFIG)
- return handle_ept_misconfig(vcpu);
+ if (exit_reason == EXIT_REASON_MSR_WRITE)
+ return kvm_emulate_wrmsr(vcpu);
+ else if (exit_reason == EXIT_REASON_PREEMPTION_TIMER)
+ return handle_preemption_timer(vcpu);
+ else if (exit_reason == EXIT_REASON_PENDING_INTERRUPT)
+ return handle_interrupt_window(vcpu);
+ else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+ return handle_external_interrupt(vcpu);
+ else if (exit_reason == EXIT_REASON_HLT)
+ return kvm_emulate_halt(vcpu);
+ else if (exit_reason == EXIT_REASON_EPT_MISCONFIG)
+ return handle_ept_misconfig(vcpu);
#endif
- return kvm_vmx_exit_handlers[exit_reason](vcpu);
- } else {
- vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n",
- exit_reason);
- dump_vmcs();
- vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
- vcpu->run->internal.suberror =
+
+ exit_reason = array_index_nospec(exit_reason,
+ kvm_vmx_max_exit_handlers);
+ if (!kvm_vmx_exit_handlers[exit_reason])
+ goto unexpected_vmexit;
+
+ return kvm_vmx_exit_handlers[exit_reason](vcpu);
+
+unexpected_vmexit:
+ vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n", exit_reason);
+ dump_vmcs();
+ vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+ vcpu->run->internal.suberror =
KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
- vcpu->run->internal.ndata = 1;
- vcpu->run->internal.data[0] = exit_reason;
- return 0;
- }
+ vcpu->run->internal.ndata = 1;
+ vcpu->run->internal.data[0] = exit_reason;
+ return 0;
}
/*
--
2.24.0.525.g8f36a354ae-goog
next prev parent reply other threads:[~2019-12-11 20:49 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 20:47 [PATCH v2 00/13] KVM: x86: Extend Spectre-v1 mitigation Marios Pomonis
2019-12-11 20:47 ` [PATCH v2 01/13] KVM: x86: Protect x86_decode_insn from Spectre-v1/L1TF attacks Marios Pomonis
2020-01-06 20:16 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 02/13] KVM: x86: Protect kvm_hv_msr_[get|set]_crash_data() " Marios Pomonis
2019-12-12 9:43 ` Vitaly Kuznetsov
2019-12-12 17:11 ` Marios Pomonis
2019-12-12 17:31 ` Christian Borntraeger
2019-12-12 17:44 ` Jim Mattson
2019-12-12 17:47 ` Christian Borntraeger
2020-01-06 20:16 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 03/13] KVM: x86: Refactor picdev_write() to prevent " Marios Pomonis
2020-01-06 20:17 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 04/13] KVM: x86: Protect ioapic_read_indirect() from " Marios Pomonis
2020-01-06 20:17 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 05/13] KVM: x86: Protect ioapic_write_indirect() " Marios Pomonis
2020-01-06 20:17 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 06/13] KVM: x86: Protect kvm_lapic_reg_write() " Marios Pomonis
2020-01-06 20:17 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 07/13] KVM: x86: Protect MSR-based index computations in fixed_msr_to_seg_unit() " Marios Pomonis
2020-01-06 20:18 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 08/13] KVM: x86: Protect MSR-based index computations in pmu.h " Marios Pomonis
2020-01-06 20:18 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 09/13] KVM: x86: Protect MSR-based index computations from Spectre-v1/L1TF attacks in x86.c Marios Pomonis
2020-01-06 20:18 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 10/13] KVM: x86: Protect memory accesses " Marios Pomonis
2020-01-06 20:19 ` Jim Mattson
2020-01-18 20:13 ` Paolo Bonzini
2019-12-11 20:47 ` Marios Pomonis [this message]
2019-12-11 20:47 ` [PATCH v2 12/13] KVM: x86: Protect DR-based index computations from Spectre-v1/L1TF attacks Marios Pomonis
2020-01-06 20:19 ` Jim Mattson
2019-12-11 20:47 ` [PATCH v2 13/13] KVM: x86: Protect pmu_intel.c " Marios Pomonis
2020-01-06 20:19 ` Jim Mattson
2020-01-18 20:18 ` [PATCH v2 00/13] KVM: x86: Extend Spectre-v1 mitigation Paolo Bonzini
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