Re: [PATCH] KVM: vgic: Fix potential double free dist->spis in __kvm_vgic_destroy()

[Auger Eric]

Hi,

On 11/28/19 7:38 AM, linmiaohe wrote:
> From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> 
> In kvm_vgic_dist_init() called from kvm_vgic_map_resources(), if
> dist->vgic_model is invalid, dist->spis will be freed without set
> dist->spis = NULL. And in vgicv2 resources clean up path,
> __kvm_vgic_destroy() will be called to free allocated resources.
> And dist->spis will be freed again in clean up chain because we
> forget to set dist->spis = NULL in kvm_vgic_dist_init() failed
> path. So double free would happen.
> 
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>

Thanks

Eric

> ---
>  virt/kvm/arm/vgic/vgic-init.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
> index 53e3969dfb52..c17c29beeb72 100644
> --- a/virt/kvm/arm/vgic/vgic-init.c
> +++ b/virt/kvm/arm/vgic/vgic-init.c
> @@ -171,6 +171,7 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
>  			break;
>  		default:
>  			kfree(dist->spis);
> +			dist->spis = NULL;
>  			return -EINVAL;
>  		}
>  	}
>