KVM: s390: clear_io_irq() requests are not expected for adapter interrupts
There is a chance to delete not yet delivered I/O interrupts if an
exploiter uses the subsystem identification word 0x0000 while
processing a KVM_DEV_FLIC_CLEAR_IO_IRQ ioctl. -EINVAL will be returned
now instead in that case.
Classic interrupts will always have bit 0x10000 set in the schid while
adapter interrupts have a zero schid. The clear_io_irq interface is
only useful for classic interrupts (as adapter interrupts belong to
many devices). Let's make this interface more strict and forbid a schid
of 0.
Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index a3da4f3..c8aacce 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2191,6 +2191,8 @@ static int clear_io_irq(struct kvm *kvm, struct kvm_device_attr *attr)
return -EINVAL;
if (copy_from_user(&schid, (void __user *) attr->addr, sizeof(schid)))
return -EFAULT;
+ if (!schid)
+ return -EINVAL;
kfree(kvm_s390_get_io_int(kvm, isc_mask, schid));
/*
* If userspace is conforming to the architecture, we can have at most