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package microsoft
import (
"encoding/json"
"errors"
"net/http"
"path"
"strings"
"github.com/nsheridan/cashier/server/auth"
"github.com/nsheridan/cashier/server/config"
"github.com/nsheridan/cashier/server/metrics"
"golang.org/x/oauth2"
"golang.org/x/oauth2/microsoft"
)
const (
name = "microsoft"
)
// Config is an implementation of `auth.Provider` for authenticating using a
// Office 365 account.
type Config struct {
config *oauth2.Config
tenant string
groups map[string]bool
whitelist map[string]bool
}
var _ auth.Provider = (*Config)(nil)
// New creates a new Microsoft provider from a configuration.
func New(c *config.Auth) (*Config, error) {
whitelist := make(map[string]bool)
for _, u := range c.UsersWhitelist {
whitelist[u] = true
}
if c.ProviderOpts["tenant"] == "" && len(whitelist) == 0 {
return nil, errors.New("either Office 365 tenant or users whitelist must be specified")
}
groupMap := make(map[string]bool)
if groups, ok := c.ProviderOpts["groups"]; ok {
for _, group := range strings.Split(groups, ",") {
groupMap[strings.Trim(group, " ")] = true
}
}
return &Config{
config: &oauth2.Config{
ClientID: c.OauthClientID,
ClientSecret: c.OauthClientSecret,
RedirectURL: c.OauthCallbackURL,
Endpoint: microsoft.AzureADEndpoint(c.ProviderOpts["tenant"]),
Scopes: []string{"user.Read.All", "Directory.Read.All"},
},
tenant: c.ProviderOpts["tenant"],
whitelist: whitelist,
groups: groupMap,
}, nil
}
// A new oauth2 http client.
func (c *Config) newClient(token *oauth2.Token) *http.Client {
return c.config.Client(oauth2.NoContext, token)
}
// Gets a response for an graph api call.
func (c *Config) getDocument(token *oauth2.Token, pathElements ...string) map[string]interface{} {
client := c.newClient(token)
url := "https://" + path.Join("graph.microsoft.com/v1.0", path.Join(pathElements...))
resp, err := client.Get(url)
if err != nil {
return nil
}
defer resp.Body.Close()
var document map[string]interface{}
if err := json.NewDecoder(resp.Body).Decode(&document); err != nil {
return nil
}
return document
}
// Get info from the "/me" endpoint of the Microsoft Graph API (MSG-API).
// https://developer.microsoft.com/en-us/graph/docs/concepts/v1-overview
func (c *Config) getMe(token *oauth2.Token, item string) string {
document := c.getDocument(token, "/me")
if value, ok := document[item].(string); ok {
return value
}
return ""
}
// Check against verified domains from "/organization" endpoint of MSG-API.
func (c *Config) verifyTenant(token *oauth2.Token) bool {
document := c.getDocument(token, "/organization")
// The domains for an organisation are in an array of structs under
// verifiedDomains, which is in a struct which is in turn an array
// of such structs under value in the document. Which in json looks
// like this:
// { "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#organization",
// "value": [ {
// ...
// "verifiedDomains": [ {
// ...
// "name": "M365x214355.onmicrosoft.com",
// } ]
// } ]
//}
var value []interface{}
var ok bool
if value, ok = document["value"].([]interface{}); !ok {
return false
}
for _, valueEntry := range value {
if value, ok = valueEntry.(map[string]interface{})["verifiedDomains"].([]interface{}); !ok {
continue
}
for _, val := range value {
domain := val.(map[string]interface{})["name"].(string)
if domain == c.tenant {
return true
}
}
}
return false
}
// Check against groups from /users/{id}/memberOf endpoint of MSG-API.
func (c *Config) verifyGroups(token *oauth2.Token) bool {
document := c.getDocument(token, "/users/me/memberOf")
var value []interface{}
var ok bool
if value, ok = document["value"].([]interface{}); !ok {
return false
}
for _, valueEntry := range value {
if group, ok := valueEntry.(map[string]interface{})["displayName"].(string); ok {
if c.groups[group] {
return true
}
}
}
return false
}
// Name returns the name of the provider.
func (c *Config) Name() string {
return name
}
// Valid validates the oauth token.
func (c *Config) Valid(token *oauth2.Token) bool {
if len(c.whitelist) > 0 && !c.whitelist[c.Email(token)] {
return false
}
if !token.Valid() {
return false
}
metrics.M.AuthValid.WithLabelValues("microsoft").Inc()
if c.tenant != "" {
if c.verifyTenant(token) {
if len(c.groups) > 0 {
return c.verifyGroups(token)
}
return true
}
}
return false
}
// Revoke disables the access token.
func (c *Config) Revoke(token *oauth2.Token) error {
return nil
}
// StartSession retrieves an authentication endpoint from Microsoft.
func (c *Config) StartSession(state string) string {
return c.config.AuthCodeURL(state,
oauth2.SetAuthURLParam("hd", c.tenant),
oauth2.SetAuthURLParam("prompt", "login"))
}
// Exchange authorizes the session and returns an access token.
func (c *Config) Exchange(code string) (*oauth2.Token, error) {
t, err := c.config.Exchange(oauth2.NoContext, code)
if err == nil {
metrics.M.AuthExchange.WithLabelValues("microsoft").Inc()
}
return t, err
}
// Email retrieves the email address of the user.
func (c *Config) Email(token *oauth2.Token) string {
return c.getMe(token, "mail")
}
// Username retrieves the username portion of the user's email address.
func (c *Config) Username(token *oauth2.Token) string {
return strings.Split(c.Email(token), "@")[0]
}
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