Write go-spiffe compatible keys

[charlieegan3]

We have been using csi-driver-spiffe with a workload based on go-spiffe and found that the EC private key created by the driver is not compatible. go-spiffe uses https://cs.opensource.google/go/go/+/go1.18.1:src/crypto/x509/pkcs8.go;l=33

We are calling Load:
https://github.com/spiffe/go-spiffe/blob/31de176038793c17cf7e77f23e61401160c7d6c9/v2/svid/x509svid/svid.go#L33

This eventually calls:
https://github.com/spiffe/go-spiffe/blob/31de176038793c17cf7e77f23e61401160c7d6c9/v2/internal/pemutil/pem.go#L110-L114

This PR when complete will have the csi driver write a compatible key format instead so that keys can be used by go-spiffe based workloads.

Signed-off-by: Charlie Egan charlieegan3@users.noreply.github.com

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[JoshVanL]

Please add a test to ensure that the x509.Load function call will work on written key pairs from this function.

[charlieegan3]

Please add a test to ensure that the x509.Load function call will work on written key pairs from this function.

I tried to create a driver and test the writeKeyPair function on that but wasn't able to create a mount when running the tests on macOS so have extracted it to a separate function and tested that in f71daf7.

Let me know what you think.

[JoshVanL]

@charlieegan3 can we not write a unit test that unit tests the writeKeyPair?

Driver will be mostly empty, expect for the store. We can use an inmemory store.

[jetstack-bot]

@charlieegan3: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cert-manager-csi-driver-spiffe-verify	f71daf7	link	true	/test pull-cert-manager-csi-driver-spiffe-verify

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[charlieegan3]

@charlieegan3 can we not write a unit test that unit tests the writeKeyPair?

Driver will be mostly empty, expect for the store. We can use an inmemory store.

Perhaps I can fashion one without using New. Let me have a play.

[jetstack-bot]

@charlieegan3: PR needs rebase.

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[charlieegan3]

Closing in favour of #13