Re: [RFC PATCH 06/28] arm64: RME: ioctls to create and configure realms

Suzuki K Poulose
2023-02-07T12:56:02Z

On 07/02/2023 12:25, Jean-Philippe Brucker wrote:
> On Fri, Jan 27, 2023 at 11:29:10AM +0000, Steven Price wrote:
>> +static int kvm_rme_config_realm(struct kvm *kvm, struct kvm_enable_cap *cap)
>> +{
>> + struct kvm_cap_arm_rme_config_item cfg;
>> + struct realm *realm = &kvm->arch.realm;
>> + int r = 0;
>> +
>> + if (kvm_realm_state(kvm) != REALM_STATE_NONE)
>> + return -EBUSY;
>
> This should also check kvm_is_realm() (otherwise we dereference a NULL
> realm).

Correct, I think this should be done way up in the stack at :

kvm_vm_ioctl_enable_cap() for KVM_CAP_ARM_RME.

>
> I was wondering about fuzzing the API to find more of this kind of issue,
> but don't know anything about it. Is there a recommended way to fuzz KVM?

Not sure either. kselftests is one possible way to drive these test at
least for unit-testing the new ABIs. This is something we plan to add.

Thanks for catching this.

Suzuki

> Thanks,
> Jean
>