Commit 4dd6f17e authored Jul 06, 2017 by Michael Mueller Committed by Christian Borntraeger Nov 09, 2017

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>

parent ee739f4b

Documentation/virtual/kvm/devices/s390_flic.txt

+3 −0

Original line number	Diff line number	Diff line
		@@ -156,3 +156,6 @@ FLIC with an unknown group or attribute gives the error code EINVAL (instead of
		ENXIO, as specified in the API documentation). It is not possible to conclude
		that a FLIC operation is unavailable based on the error code resulting from a
		usage attempt.

		Note: The KVM_DEV_FLIC_CLEAR_IO_IRQ ioctl will return EINVAL in case a zero
		schid is specified.

arch/s390/kvm/interrupt.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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