pki: clean up fuzzer

[AdamKorcz]

Summary

Removes a check that is not correct.

For example, NewPublicKey in the ssh package parses the input data into the key and the comment:

rekor/pkg/pki/ssh/ssh.go

Lines 82 to 99 in 7359299

	func NewPublicKey(r io.Reader) (*PublicKey, error) {
	// 64K seems generous as a limit for valid SSH keys
	// we use http.MaxBytesReader and pass nil for ResponseWriter to reuse stdlib
	// and not reimplement this; There is a proposal for this to be fixed in 1.20
	// https://github.com/golang/go/issues/51115
	// TODO: switch this to stdlib once golang 1.20 comes out
	rawPub, err := io.ReadAll(http.MaxBytesReader(nil, io.NopCloser(r), 65536))
	if err != nil {
	return nil, err
	}
	key, comment, _, _, err := ssh.ParseAuthorizedKey(rawPub)
	if err != nil {
	return nil, err
	}
	return &PublicKey{key: key, comment: comment}, nil
	}

but canonicalizes only the key value:

rekor/pkg/pki/ssh/ssh.go

Lines 102 to 107 in 7359299

	func (k PublicKey) CanonicalValue() ([]byte, error) {
	if k.key == nil {
	return nil, fmt.Errorf("ssh public key has not been initialized")
	}
	return ssh.MarshalAuthorizedKey(k.key), nil
	}

and when then fuzzer then creates another key with the canonical value, the two public keys will differ and the comparison statement:

	if !cmp.Equal(pub1, pub2, cmpOpts...) {
	        t.Fatal("The two public keys should be equal but are not")
	}

... will fail.

Each PKI does something different, so I am removing this check in the fuzzer to let it run without interruption.

Release Note

Documentation

[codecov]

Codecov Report

Merging #1594 (56efb52) into main (05bdadc) will increase coverage by 18.72%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             main    #1594       +/-   ##
===========================================
+ Coverage   48.37%   67.09%   +18.72%     
===========================================
  Files          83       83               
  Lines        8389     8389               
===========================================
+ Hits         4058     5629     +1571     
+ Misses       3525     2086     -1439     
+ Partials      806      674      -132     

Flag	Coverage Δ
e2etests	48.37% <ø> (ø)
unittests	47.84% <ø> (?)

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see 45 files with indirect coverage changes