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

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 8/4/26 8:06 AM, Christian Borntraeger wrote:
> __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>

Reviewed-by: Matthew Rosato <mjrosato@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;
>