Add fuzzer and OSS-fuzz build script

[AdamKorcz]

This PR adds a go-fuzz fuzzer that targets WriteToken as well as a build script to integrate Kops into OSS-fuzz.

I have the integration script available for OSS-fuzz and will be happy to finalize the integration. For this, at least one maintainers email is needed for potential bug reports.

Fuzzing is a way of testing programs whereby pseudo-random data is passed to a target application with the goal of finding bugs and vulnerabilities. Kubernetes is already being fuzzed continuously by way of OSS-fuzz, and this has led to finding bugs and vulnerabilities.

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[johngmyers]

Please squash the commits.

Perusing the OSS-Fuzz documentation, I was not able to find a definition of the API for a fuzz target, particularly not a definition of the integer return values.

I also don't see any provision of a seed corpus or dictionary. Shouldn't this be tuned towards JSON?

/ok-to-test

[AdamKorcz]

I have not forgotten about this PR. I will ping you once it is ready to review.

[AdamKorcz]

Perusing the OSS-Fuzz documentation, I was not able to find a definition of the API for a fuzz target, particularly not a definition of the integer return values.

The fuzzer is implemented by way of go-fuzz, and some documentation on the integer return values can be found here: https://github.com/dvyukov/go-fuzz#usage

I also don't see any provision of a seed corpus or dictionary. Shouldn't this be tuned towards JSON?

To be meticulous: We don't have to do this, but it will help the fuzzer significantly. During build process we will clone https://github.com/google/AFL and get the json.dict from there, and we will do the same for the corpus at https://github.com/dvyukov/go-fuzz-corpus. The two commands in the build file moves the dict and zip files to the correct location with the correct names.

[AdamKorcz]

@johngmyers Does it look fine? From my side I consider the corpus and the dict added and all that is needed now is a squash.

[johngmyers]

Please squash and I'll approve.

[AdamKorcz]

Done!

[mikesplain]

Thanks @AdamKorcz!

/lgtm

[mikesplain]

/approve

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AdamKorcz, mikesplain

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[rifelpet]

@AdamKorcz is the fuzzing going to be happening on some platform that we can access? you mentioned needing an email address: ideally we could use a distribution list but I don't know if we have one setup other than a few announcement lists

[AdamKorcz]

@rifelpet The fuzzing will be done by OSS-fuzz which offers a dashboard for found bugs, stats and more. The dashboard is available at https://oss-fuzz.com/, and to get access to the kOps project maintainers need to add their email address in the project.yaml file here. For now, please leave all maintainer email addresses in the current integration PR ( google/oss-fuzz#4729 ) as we are currently discussing whether or not kOps and Kubernetes should be in the same integration in OSS-fuzz. Inputs on that thread are welcome.