[PATCH AUTOSEL 5.4 074/330] KVM: arm/arm64: vgic: Fix potential double free dist->spis in __kvm_vgic_destroy()

[Sasha Levin]

From: Miaohe Lin <linmiaohe@xxxxxxxxxx>

[ Upstream commit 0bda9498dd45280e334bfe88b815ebf519602cc3 ]

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>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1574923128-19956-1-git-send-email-linmiaohe@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 6f50c429196de..6d85c6d894c39 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -177,6 +177,7 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 			break;
 		default:
 			kfree(dist->spis);
+			dist->spis = NULL;
 			return -EINVAL;
 		}
 	}
-- 
2.25.1