Commit b85de33a authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger

KVM: s390: avoid memory overwrites on emergency signal injection

Commit 383d0b05 ("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: default avatarDominik Dingel <dingel@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v3.19+ db27a7a3 KVM: Provide function for VCPU lookup by id
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent db27a7a3
......@@ -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);
......
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