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/openshift-online/ocm-sdk-go/authentication/context.go

@@ -0,0 +1,67 @@
+/*
+Copyright (c) 2019 Red Hat, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// This file contains functions that extract information from the context.
+
+package authentication
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/dgrijalva/jwt-go"
+)
+
+// ContextWithToken creates a new context containing the given token.
+func ContextWithToken(parent context.Context, token *jwt.Token) context.Context {
+	return context.WithValue(parent, tokenKeyValue, token)
+}
+
+// TokenFromContext extracts the JSON web token of the user from the context. If no token is found
+// in the context then the result will be nil.
+func TokenFromContext(ctx context.Context) (result *jwt.Token, err error) {
+	switch token := ctx.Value(tokenKeyValue).(type) {
+	case nil:
+	case *jwt.Token:
+		result = token
+	default:
+		err = fmt.Errorf(
+			"expected a token in the '%s' context value, but got '%T'",
+			tokenKeyValue, token,
+		)
+	}
+	return
+}
+
+// BearerFromContext extracts the bearer token of the user from the context. If no user is found in
+// the context then the result will be the empty string.
+func BearerFromContext(ctx context.Context) (result string, err error) {
+	token, err := TokenFromContext(ctx)
+	if err != nil {
+		return
+	}
+	if token == nil {
+		return
+	}
+	result = token.Raw
+	return
+}
+
+// tokenKeyType is the type of the key used to store the token in the context.
+type tokenKeyType string
+
+// tokenKeyValue is the key used to store the token in the context:
+const tokenKeyValue tokenKeyType = "token"

vendor/github.com/openshift-online/ocm-sdk-go/authentication/helpers.go

@@ -0,0 +1,57 @@
+/*
+Copyright (c) 2021 Red Hat, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// This file contains helper functions used in several places in the package.
+
+package authentication
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/dgrijalva/jwt-go"
+)
+
+// tokenRemaining determines if the given token will eventually expire (offile access tokens, for
+// example, never expire) and the time till it expires. That time will be positive if the token
+// isn't expired, and negative if the token has already expired.
+//
+// For tokens that don't have the `exp` claim, or that have it with value zero (typical for offline
+// access tokens) the result will always be `false` and zero.
+func tokenRemaining(token *jwt.Token, now time.Time) (expires bool, duration time.Duration,
+	err error) {
+	claims, ok := token.Claims.(jwt.MapClaims)
+	if !ok {
+		err = fmt.Errorf("expected map claims but got %T", claims)
+		return
+	}
+	var exp float64
+	claim, ok := claims["exp"]
+	if !ok {
+		return
+	}
+	exp, ok = claim.(float64)
+	if !ok {
+		err = fmt.Errorf("expected floating point 'exp' but got %T", claim)
+		return
+	}
+	if exp == 0 {
+		return
+	}
+	duration = time.Unix(int64(exp), 0).Sub(now)
+	expires = true
+	return
+}