KVM: arm64: Tear down vGIC on failed vCPU creation

commit 250f25367b58d8c65a1b060a2dda037eea09a672 upstream.

If kvm_arch_vcpu_create() fails to share the vCPU page with the
hypervisor, we propagate the error back to the ioctl but leave the
vGIC vCPU data initialised. Note only does this leak the corresponding
memory when the vCPU is destroyed but it can also lead to use-after-free
if the redistributor device handling tries to walk into the vCPU.

Add the missing cleanup to kvm_arch_vcpu_create(), ensuring that the
vGIC vCPU structures are destroyed on error.

Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250314133409.9123-1-will@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 9818cde948ca9c7028220322aea4ff3706542c93..fe4314af8eeccc6b80c9210df0ae5965911a3fb5 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -391,7 +391,11 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
        if (err)
                return err;
 
-       return kvm_share_hyp(vcpu, vcpu + 1);
+       err = kvm_share_hyp(vcpu, vcpu + 1);
+       if (err)
+               kvm_vgic_vcpu_destroy(vcpu);
+
+       return err;
 }
 
 void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)