cacert-boardvoting/cmd/boardvoting/config.go

/*
Copyright 2017-2022 CAcert Inc.
SPDX-License-Identifier: Apache-2.0

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 main

import (
	"context"
	"encoding/base64"
	"errors"
	"fmt"
	"io/ioutil"

	"github.com/gorilla/sessions"
	"gopkg.in/yaml.v2"
)

const (
	cookieSecretMinLen    = 32
	csrfKeyLength         = 32
	httpIdleTimeout       = 5
	httpReadHeaderTimeout = 10
	httpReadTimeout       = 10
	httpWriteTimeout      = 60
	sessionCookieName     = "votesession"
)

type Config struct {
	NoticeMailAddress         string `yaml:"notice_mail_address"`
	VoteNoticeMailAddress     string `yaml:"vote_notice_mail_address"`
	NotificationSenderAddress string `yaml:"notification_sender_address"`
	DatabaseFile              string `yaml:"database_file"`
	ClientCACertificates      string `yaml:"client_ca_certificates"`
	ServerCert                string `yaml:"server_certificate"`
	ServerKey                 string `yaml:"server_key"`
	CookieSecret              string `yaml:"cookie_secret"`
	CsrfKey                   string `yaml:"csrf_key"`
	BaseURL                   string `yaml:"base_url"`
	HTTPAddress               string `yaml:"http_address,omitempty"`
	HTTPSAddress              string `yaml:"https_address,omitempty"`
	MailServer                struct {
		Host string `yaml:"host"`
		Port int    `yaml:"port"`
	} `yaml:"mail_server"`
}

type configKey int

const (
	ctxConfig configKey = iota
	ctxCookieStore
)

func parseConfig(ctx context.Context, configFile string) (context.Context, error) {
	source, err := ioutil.ReadFile(configFile)
	if err != nil {
		return nil, fmt.Errorf("could not read configuration file %s: %w", configFile, err)
	}

	config := &Config{
		HTTPAddress:  "127.0.0.1:8000",
		HTTPSAddress: "127.0.0.1:8433",
	}

	if err := yaml.Unmarshal(source, config); err != nil {
		return nil, fmt.Errorf("could not parse configuration: %w", err)
	}

	cookieSecret, err := base64.StdEncoding.DecodeString(config.CookieSecret)
	if err != nil {
		return nil, fmt.Errorf("could not decode cookie secret: %w", err)
	}

	if len(cookieSecret) < cookieSecretMinLen {
		return nil, fmt.Errorf("cookie secret is less than the minimum require %d bytes long", cookieSecretMinLen)
	}

	csrfKey, err := base64.StdEncoding.DecodeString(config.CsrfKey)
	if err != nil {
		return nil, fmt.Errorf("could not decode CSRF key: %w", err)
	}

	if len(csrfKey) != csrfKeyLength {
		return nil, fmt.Errorf("CSRF key must be exactly %d bytes long but is %d bytes long", csrfKeyLength, len(csrfKey))
	}

	cookieStore := sessions.NewCookieStore(cookieSecret)
	cookieStore.Options.Secure = true

	ctx = context.WithValue(ctx, ctxConfig, config)
	ctx = context.WithValue(ctx, ctxCookieStore, cookieStore)

	return ctx, nil
}

func GetConfig(ctx context.Context) (*Config, error) {
	config, ok := ctx.Value(ctxConfig).(*Config)
	if !ok {
		return nil, errors.New("invalid value type for config in context")
	}

	return config, nil
}

func GetCookieStore(ctx context.Context) (*sessions.CookieStore, error) {
	cookieStore, ok := ctx.Value(ctxConfig).(*sessions.CookieStore)
	if !ok {
		return nil, errors.New("invalid value type for cookie store in context")
	}

	return cookieStore, nil
}