Copy nested capabilities_ex structure during interface init

[mtfriesen]

Description

Describe the purpose of and changes within this Pull Request.

#845 exposed a latent bug in the interface binding module: each interface copied the caller's capabilities struct into the interface object, but it left dangling pointers within that struct. If an interface was later removed, the new XdpRxQueueEnableChecksumOffload routine could dereference the dangling pointer and AV.

The expected lifetime of the caller's structure isn't clearly documented, but it certainly can't persist beyond the interface's final RemoveInterfaceComplete callback, which is the state during the CI bugcheck.

Also do the same thing for the Hooks nested pointer.
Also validate the size of the capabilities struct is large enough to contain the new/optional RxChecksumSupported field.

Resolves #922

Testing

Do any existing tests cover this change? Are new tests needed?

Builds locally, CI.

Documentation

Is there any documentation impact for this change?

N/A.

Installation

Is there any installer impact for this change?

N/A.

[Copilot]

Pull Request Overview

This PR fixes a dangling pointer bug in the XDP interface binding module where interface objects copied the caller's capabilities structure but left nested pointers dangling, potentially causing an access violation when interfaces were removed.

Key changes:

• Allocate and deep-copy the nested CapabilitiesEx structure during interface initialization
• Free the allocated CapabilitiesEx memory during interface cleanup

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[guhetier]

I also see a Hooks array in the capability struct, is its lifetime is independent from the caller structure?

[mtfriesen]

I also see a Hooks array in the capability struct, is its lifetime is independent from the caller structure?

Yeah, good catch. That's not causing us immediate problems right now, but we should be consistent and protect the lifetimes and avoid dangling pointers.