From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] KVM: x86: Avoid theoretical NULL pointer dereference in kvm_irq_delivery_to_apic_fast()
Date: Fri, 25 Mar 2022 14:21:39 +0100 [thread overview]
Message-ID: <20220325132140.25650-3-vkuznets@redhat.com> (raw)
In-Reply-To: <20220325132140.25650-1-vkuznets@redhat.com>
When kvm_irq_delivery_to_apic_fast() is called with APIC_DEST_SELF
shorthand, 'src' must not be NULL. Crash the VM with KVM_BUG_ON()
instead of crashing the host.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/kvm/lapic.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 80a2020c4db4..66b0eb0bda94 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1024,6 +1024,10 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
*r = -1;
if (irq->shorthand == APIC_DEST_SELF) {
+ if (KVM_BUG_ON(!src, kvm)) {
+ *r = 0;
+ return true;
+ }
*r = kvm_apic_set_irq(src->vcpu, irq, dest_map);
return true;
}
--
2.35.1
next prev parent reply other threads:[~2022-03-25 13:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-25 13:21 [PATCH 0/3] KVM: x86: Prefent NULL prointer " Vitaly Kuznetsov
2022-03-25 13:21 ` [PATCH 1/3] KVM: x86: Check lapic_in_kernel() before attempting to set a SynIC irq Vitaly Kuznetsov
2022-03-25 13:21 ` Vitaly Kuznetsov [this message]
2022-03-25 13:21 ` [PATCH 3/3] KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC wasn't activated Vitaly Kuznetsov
2022-03-25 13:33 ` [PATCH 0/3] KVM: x86: Prefent NULL prointer dereference in kvm_irq_delivery_to_apic_fast() Paolo Bonzini
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