git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 00b5f37189d24ac3ed46cb7f11742094778c46ce Mon Sep 17 00:00:00 2001
   2 From: Vitaly Kuznetsov <vkuznets@redhat.com>
   3 Date: Fri, 25 Mar 2022 14:21:39 +0100
   4 Subject: KVM: x86: Avoid theoretical NULL pointer dereference in kvm_irq_delivery_to_apic_fast()
   5
   6 From: Vitaly Kuznetsov <vkuznets@redhat.com>
   7
   8 commit 00b5f37189d24ac3ed46cb7f11742094778c46ce upstream.
   9
  10 When kvm_irq_delivery_to_apic_fast() is called with APIC_DEST_SELF
  11 shorthand, 'src' must not be NULL. Crash the VM with KVM_BUG_ON()
  12 instead of crashing the host.
  13
  14 Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
  15 Message-Id: <20220325132140.25650-3-vkuznets@redhat.com>
  16 Cc: stable@vger.kernel.org
  17 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19 ---
  20  arch/x86/kvm/lapic.c |    4 ++++
  21  1 file changed, 4 insertions(+)
  22
  23 --- a/arch/x86/kvm/lapic.c
  24 +++ b/arch/x86/kvm/lapic.c
  25 @@ -987,6 +987,10 @@ bool kvm_irq_delivery_to_apic_fast(struc
  26         *r = -1;
  27
  28         if (irq->shorthand == APIC_DEST_SELF) {
  29 +               if (KVM_BUG_ON(!src, kvm)) {
  30 +                       *r = 0;
  31 +                       return true;
  32 +               }
  33                 *r = kvm_apic_set_irq(src->vcpu, irq, dest_map);
  34                 return true;
  35         }