[PATCH 2/3] KVM: s390: zero initialize irq for inject_pfault_token

[Christian Borntraeger <borntraeger@linux.ibm.com>]

__kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of
the on-stack struct kvm_s390_irq but the full ext substructure is copied
into the cpu local variable on inject. ext_params and pad contain stale
stack values.

Interrupt delivery only uses ext_params2, so nothing leaks, but a host
user can use the migration ioctls to get to the data.

Fix by zero-initializing the irq struct.

Fixes: 383d0b050106 ("KVM: s390: handle pending local interrupts via bitmap")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
---
 arch/s390/kvm/kvm-s390.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4a38de3d6758..447e6a61f886 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4474,7 +4474,7 @@ static void __kvm_inject_pfault_token(struct kvm_vcpu *vcpu, bool start_token,
 				     unsigned long token)
 {
 	struct kvm_s390_interrupt inti;
-	struct kvm_s390_irq irq;
+	struct kvm_s390_irq irq = {};
 	struct kvm_s390_interrupt_info *inti_mem = NULL;
 	int ret = 0;
 
-- 
2.53.0