From b85de33a1a3433487b6a721cfdce25ec8673e622 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 5 Nov 2015 09:38:15 +0100 Subject: [PATCH] KVM: s390: avoid memory overwrites on emergency signal injection Commit 383d0b050106 ("KVM: s390: handle pending local interrupts via bitmap") introduced a possible memory overwrite from user space. User space could pass an invalid emergency signal code (sending VCPU) and therefore exceed the bitmap. Let's take care of this case and check that the id is in the valid range. Reviewed-by: Dominik Dingel Cc: stable@vger.kernel.org # v3.19+ db27a7a KVM: Provide function for VCPU lookup by id Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/kvm/interrupt.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 373e32346d68..7242c2da4009 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1110,6 +1110,10 @@ static int __inject_sigp_emergency(struct kvm_vcpu *vcpu, trace_kvm_s390_inject_vcpu(vcpu->vcpu_id, KVM_S390_INT_EMERGENCY, irq->u.emerg.code, 0); + /* sending vcpu invalid */ + if (kvm_get_vcpu_by_id(vcpu->kvm, irq->u.emerg.code) == NULL) + return -EINVAL; + set_bit(irq->u.emerg.code, li->sigp_emerg_pending); set_bit(IRQ_PEND_EXT_EMERGENCY, &li->pending_irqs); atomic_or(CPUSTAT_EXT_INT, li->cpuflags); -- 2.20.1