auth: OpenID/OAUth2 middleware

2 configurations for the listeners are now possible:
- enableJWT=false with client ssl auth
- enableJWT=true with https

Actual verification of the tokens is handled by
https://github.com/openshift-online/ocm-sdk-go.

An authentication handler is run as the top level handler, before any
routing is done. Routes which do not require authentication should be
listed as exceptions.

Authentication can be restricted using an ACL file which allows
filtering based on JWT claims. For more information see the inline
comments in ocm-sdk/authentication.

As an added quirk the `-v` flag for the osbuild-composer executable was
changed to `-verbose` to avoid flag collision with glog which declares
the `-v` flag in the package `init()` function. The ocm-sdk depends on
glog and pulls it in.

vendor/github.com/golang-jwt/jwt/rsa_utils.go

@@ -0,0 +1,101 @@
+package jwt
+
+import (
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+)
+
+var (
+	ErrKeyMustBePEMEncoded = errors.New("Invalid Key: Key must be PEM encoded PKCS1 or PKCS8 private key")
+	ErrNotRSAPrivateKey    = errors.New("Key is not a valid RSA private key")
+	ErrNotRSAPublicKey     = errors.New("Key is not a valid RSA public key")
+)
+
+// Parse PEM encoded PKCS1 or PKCS8 private key
+func ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKCS1PrivateKey(block.Bytes); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
+		return nil, ErrNotRSAPrivateKey
+	}
+
+	return pkey, nil
+}
+
+// Parse PEM encoded PKCS1 or PKCS8 private key protected with password
+func ParseRSAPrivateKeyFromPEMWithPassword(key []byte, password string) (*rsa.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	var parsedKey interface{}
+
+	var blockDecrypted []byte
+	if blockDecrypted, err = x509.DecryptPEMBlock(block, []byte(password)); err != nil {
+		return nil, err
+	}
+
+	if parsedKey, err = x509.ParsePKCS1PrivateKey(blockDecrypted); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(blockDecrypted); err != nil {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
+		return nil, ErrNotRSAPrivateKey
+	}
+
+	return pkey, nil
+}
+
+// Parse PEM encoded PKCS1 or PKCS8 public key
+func ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	// Parse the key
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
+		if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
+			parsedKey = cert.PublicKey
+		} else {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PublicKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PublicKey); !ok {
+		return nil, ErrNotRSAPublicKey
+	}
+
+	return pkey, nil
+}