Commit dcf96f7a authored by Janosch Frank's avatar Janosch Frank Committed by Christian Borntraeger
Browse files

KVM: s390: Limit adapter indicator access to mapped page 



While we check the address for errors, we don't seem to check the bit
offsets and since they are 32 and 64 bits a lot of memory can be
reached indirectly via those offsets.

Fixes: 84223598 ("KVM: s390: irq routing for adapter interrupts.")
Suggested-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Tested-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
parent b00be773

arch/s390/kvm/interrupt.c

+12 −0
Original line number Diff line number Diff line
@@ -2724,6 +2724,9 @@ static unsigned long get_ind_bit(__u64 addr, unsigned long bit_nr, bool swap) 


	bit = bit_nr + (addr % PAGE_SIZE) * 8;



	/* kvm_set_routing_entry() should never allow this to happen */

	WARN_ON_ONCE(bit > (PAGE_SIZE * BITS_PER_BYTE - 1));



	return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit;

}
@@ -2852,6 +2855,7 @@ int kvm_set_routing_entry(struct kvm *kvm, 
			  struct kvm_kernel_irq_routing_entry *e,

			  const struct kvm_irq_routing_entry *ue)

{

	const struct kvm_irq_routing_s390_adapter *adapter;

	u64 uaddr_s, uaddr_i;

	int idx;
@@ -2862,6 +2866,14 @@ int kvm_set_routing_entry(struct kvm *kvm, 
			return -EINVAL;

		e->set = set_adapter_int;



		adapter = &ue->u.adapter;

		if (adapter->summary_addr + (adapter->summary_offset / 8) >=

		    (adapter->summary_addr & PAGE_MASK) + PAGE_SIZE)

			return -EINVAL;

		if (adapter->ind_addr + (adapter->ind_offset / 8) >=

		    (adapter->ind_addr & PAGE_MASK) + PAGE_SIZE)

			return -EINVAL;



		idx = srcu_read_lock(&kvm->srcu);

		uaddr_s = gpa_to_hva(kvm, ue->u.adapter.summary_addr);

		uaddr_i = gpa_to_hva(kvm, ue->u.adapter.ind_addr);