Authentication processor 2/4 - Add auth context and interface (#1808)

* Authentication processor 1/4 - Add configauth

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

* Authentication processor 2/4 - Add auth context and interface

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

internal/auth/authenticator.go

@@ -0,0 +1,95 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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.
+
+package auth
+
+import (
+	"context"
+	"errors"
+	"io"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+
+	"go.opentelemetry.io/collector/config/configauth"
+)
+
+var (
+	errNoOIDCProvided   = errors.New("no OIDC information provided")
+	errMetadataNotFound = errors.New("no request metadata found")
+	errNotImplemented   = errors.New("not implemented")
+	defaultAttribute    = "authorization"
+)
+
+// Authenticator will authenticate the incoming request/RPC
+type Authenticator interface {
+	io.Closer
+
+	// Authenticate checks whether the given context contains valid auth data. Successfully authenticated calls will always return a nil error and a context with the auth data.
+	Authenticate(context.Context, map[string][]string) (context.Context, error)
+
+	// Start will
+	Start(context.Context) error
+
+	// UnaryInterceptor is a helper method to provide a gRPC-compatible UnaryInterceptor, typically calling the authenticator's Authenticate method.
+	UnaryInterceptor(context.Context, interface{}, *grpc.UnaryServerInfo, grpc.UnaryHandler) (interface{}, error)
+
+	// StreamInterceptor is a helper method to provide a gRPC-compatible StreamInterceptor, typically calling the authenticator's Authenticate method.
+	StreamInterceptor(interface{}, grpc.ServerStream, *grpc.StreamServerInfo, grpc.StreamHandler) error
+}
+
+type authenticateFunc func(context.Context, map[string][]string) (context.Context, error)
+
+// New creates an authenticator based on the given configuration
+func New(cfg configauth.Authentication) (Authenticator, error) {
+	if cfg.OIDC == nil {
+		return nil, errNoOIDCProvided
+	}
+
+	if len(cfg.Attribute) == 0 {
+		cfg.Attribute = defaultAttribute
+	}
+
+	return nil, errNotImplemented
+}
+
+func defaultUnaryInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler, authenticate authenticateFunc) (interface{}, error) {
+	headers, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, errMetadataNotFound
+	}
+
+	ctx, err := authenticate(ctx, headers)
+	if err != nil {
+		return nil, err
+	}
+
+	return handler(ctx, req)
+}
+
+func defaultStreamInterceptor(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler, authenticate authenticateFunc) error {
+	ctx := stream.Context()
+	headers, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return errMetadataNotFound
+	}
+
+	// TODO: how to replace the context from the stream?
+	_, err := authenticate(ctx, headers)
+	if err != nil {
+		return err
+	}
+
+	return handler(srv, stream)
+}

internal/auth/authenticator_test.go

@@ -0,0 +1,197 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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.
+
+package auth
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+
+	"go.opentelemetry.io/collector/config/configauth"
+)
+
+func TestNew(t *testing.T) {
+	// test
+	p, err := New(configauth.Authentication{
+		OIDC: &configauth.OIDC{
+			Audience:  "some-audience",
+			IssuerURL: "http://example.com",
+		},
+	})
+
+	// verify
+	assert.Nil(t, p)
+	assert.Equal(t, errNotImplemented, err)
+}
+
+func TestMissingOIDC(t *testing.T) {
+	// test
+	p, err := New(configauth.Authentication{})
+
+	// verify
+	assert.Nil(t, p)
+	assert.Equal(t, errNoOIDCProvided, err)
+}
+
+func TestDefaultUnaryInterceptorAuthSucceeded(t *testing.T) {
+	// prepare
+	handlerCalled := false
+	authCalled := false
+	authFunc := func(context.Context, map[string][]string) (context.Context, error) {
+		authCalled = true
+		return context.Background(), nil
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		handlerCalled = true
+		return nil, nil
+	}
+	ctx := metadata.NewIncomingContext(context.Background(), metadata.Pairs("authorization", "some-auth-data"))
+
+	// test
+	res, err := defaultUnaryInterceptor(ctx, nil, &grpc.UnaryServerInfo{}, handler, authFunc)
+
+	// verify
+	assert.Nil(t, res)
+	assert.NoError(t, err)
+	assert.True(t, authCalled)
+	assert.True(t, handlerCalled)
+}
+
+func TestDefaultUnaryInterceptorAuthFailure(t *testing.T) {
+	// prepare
+	authCalled := false
+	expectedErr := fmt.Errorf("not authenticated")
+	authFunc := func(context.Context, map[string][]string) (context.Context, error) {
+		authCalled = true
+		return context.Background(), expectedErr
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		assert.FailNow(t, "the handler should not have been called on auth failure!")
+		return nil, nil
+	}
+	ctx := metadata.NewIncomingContext(context.Background(), metadata.Pairs("authorization", "some-auth-data"))
+
+	// test
+	res, err := defaultUnaryInterceptor(ctx, nil, &grpc.UnaryServerInfo{}, handler, authFunc)
+
+	// verify
+	assert.Nil(t, res)
+	assert.Equal(t, expectedErr, err)
+	assert.True(t, authCalled)
+}
+
+func TestDefaultUnaryInterceptorMissingMetadata(t *testing.T) {
+	// prepare
+	authFunc := func(context.Context, map[string][]string) (context.Context, error) {
+		assert.FailNow(t, "the auth func should not have been called!")
+		return context.Background(), nil
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		assert.FailNow(t, "the handler should not have been called!")
+		return nil, nil
+	}
+
+	// test
+	res, err := defaultUnaryInterceptor(context.Background(), nil, &grpc.UnaryServerInfo{}, handler, authFunc)
+
+	// verify
+	assert.Nil(t, res)
+	assert.Equal(t, errMetadataNotFound, err)
+}
+
+func TestDefaultStreamInterceptorAuthSucceeded(t *testing.T) {
+	// prepare
+	handlerCalled := false
+	authCalled := false
+	authFunc := func(context.Context, map[string][]string) (context.Context, error) {
+		authCalled = true
+		return context.Background(), nil
+	}
+	handler := func(srv interface{}, stream grpc.ServerStream) error {
+		handlerCalled = true
+		return nil
+	}
+	ctx := metadata.NewIncomingContext(context.Background(), metadata.Pairs("authorization", "some-auth-data"))
+	streamServer := &mockServerStream{
+		ctx: ctx,
+	}
+
+	// test
+	err := defaultStreamInterceptor(nil, streamServer, &grpc.StreamServerInfo{}, handler, authFunc)
+
+	// verify
+	assert.NoError(t, err)
+	assert.True(t, authCalled)
+	assert.True(t, handlerCalled)
+}
+
+func TestDefaultStreamInterceptorAuthFailure(t *testing.T) {
+	// prepare
+	authCalled := false
+	expectedErr := fmt.Errorf("not authenticated")
+	authFunc := func(context.Context, map[string][]string) (context.Context, error) {
+		authCalled = true
+		return context.Background(), expectedErr
+	}
+	handler := func(srv interface{}, stream grpc.ServerStream) error {
+		assert.FailNow(t, "the handler should not have been called on auth failure!")
+		return nil
+	}
+	ctx := metadata.NewIncomingContext(context.Background(), metadata.Pairs("authorization", "some-auth-data"))
+	streamServer := &mockServerStream{
+		ctx: ctx,
+	}
+
+	// test
+	err := defaultStreamInterceptor(nil, streamServer, &grpc.StreamServerInfo{}, handler, authFunc)
+
+	// verify
+	assert.Equal(t, expectedErr, err)
+	assert.True(t, authCalled)
+}
+
+func TestDefaultStreamInterceptorMissingMetadata(t *testing.T) {
+	// prepare
+	authFunc := func(context.Context, map[string][]string) (context.Context, error) {
+		assert.FailNow(t, "the auth func should not have been called!")
+		return context.Background(), nil
+	}
+	handler := func(srv interface{}, stream grpc.ServerStream) error {
+		assert.FailNow(t, "the handler should not have been called!")
+		return nil
+	}
+	streamServer := &mockServerStream{
+		ctx: context.Background(),
+	}
+
+	// test
+	err := defaultStreamInterceptor(nil, streamServer, &grpc.StreamServerInfo{}, handler, authFunc)
+
+	// verify
+	assert.Equal(t, errMetadataNotFound, err)
+}
+
+type mockServerStream struct {
+	grpc.ServerStream
+	ctx context.Context
+}
+
+func (m *mockServerStream) Context() context.Context {
+	return m.ctx
+}

internal/auth/context.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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.
+
+package auth
+
+import "context"
+
+var (
+	subjectKey = subjectType{}
+	groupsKey  = groupsType{}
+)
+
+type subjectType struct{}
+type groupsType struct{}
+
+// SubjectFromContext returns a list of groups the subject in the context belongs to
+func SubjectFromContext(ctx context.Context) (string, bool) {
+	value, ok := ctx.Value(subjectKey).(string)
+	return value, ok
+}
+
+// GroupsFromContext returns a list of groups the subject in the context belongs to
+func GroupsFromContext(ctx context.Context) ([]string, bool) {
+	value, ok := ctx.Value(groupsKey).([]string)
+	return value, ok
+}