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google: Support restricting access to a specific group(s)

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This commit is contained in:
Justin Burnham 2015-08-20 03:07:02 -07:00
parent d1c0208824
commit 3fd8f911c2
10 changed files with 242 additions and 19 deletions
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13
Godeps
View File

@ -1,5 +1,8 @@
github.com/BurntSushi/toml 3883ac1ce943878302255f538fce319d23226223
github.com/bitly/go-simplejson 3378bdcb5cebedcbf8b5750edee28010f128fe24
github.com/mreiferson/go-options ee94b57f2fbf116075426f853e5abbcdfeca8b3d
github.com/bmizerany/assert e17e99893cb6509f428e1728281c2ad60a6b31e3
gopkg.in/fsnotify.v1 v1.2.0
github.com/BurntSushi/toml 3883ac1ce943878302255f538fce319d23226223
github.com/bitly/go-simplejson 3378bdcb5cebedcbf8b5750edee28010f128fe24
github.com/mreiferson/go-options ee94b57f2fbf116075426f853e5abbcdfeca8b3d
github.com/bmizerany/assert e17e99893cb6509f428e1728281c2ad60a6b31e3
gopkg.in/fsnotify.v1 v1.2.0
golang.org/x/oauth2 397fe7649477ff2e8ced8fc0b2696f781e53745a
golang.org/x/oauth2/google 397fe7649477ff2e8ced8fc0b2696f781e53745a
google.golang.org/api/admin/directory/v1 a5c3e2a4792aff40e59840d9ecdff0542a202a80

29
README.md
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@ -51,6 +51,26 @@ For Google, the registration steps are:
It's recommended to refresh sessions on a short interval (1h) with `cookie-refresh` setting which validates that the account is still authorized.
#### Restrict auth to specific Google groups on your domain. (optional)
1. Create a service account: https://developers.google.com/identity/protocols/OAuth2ServiceAccount and make sure to download the json file.
2. Make note of the Client ID for a future step.
3. Under "APIs & Auth", choose APIs.
4. Click on Admin SDK and then Enable API.
5. Follow the steps on https://developers.google.com/admin-sdk/directory/v1/guides/delegation#delegate_domain-wide_authority_to_your_service_account and give the client id from step 2 the following oauth scopes:
```
https://www.googleapis.com/auth/admin.directory.group.readonly
https://www.googleapis.com/auth/admin.directory.user.readonly
```
6. Follow the steps on https://support.google.com/a/answer/60757 to enable Admin API access.
7. Create or choose an existing administrative email address on the Gmail domain to assign to the ```google-admin-email``` flag. This email will be impersonated by this client to make calls to the Admin SDK. See the note on the link from step 5 for the reason why.
8. Create or choose an existing email group and set that email to the ```google-group``` flag. You can pass multiple instances of this flag with different groups
and the user will be checked against all the provided groups.
9. Lock down the permissions on the json file downloaded from step 1 so only oauth2_proxy is able to read the file and set the path to the file in the ```google-service-account-json``` flag.
10. Restart oauth2_proxy.
Note: The user is checked against the group members list on initial authentication and every time the token is refreshed ( about once an hour ).
### GitHub Auth Provider
1. Create a new project: https://github.com/settings/developers
@ -110,6 +130,10 @@ Usage of oauth2_proxy:
-email-domain=: authenticate emails with the specified domain (may be given multiple times). Use * to authenticate any email
-github-org="": restrict logins to members of this organisation
-github-team="": restrict logins to members of this team
-google-group="": restrict logins to members of this google group
-google-admin-email="": the google admin to impersonate for api calls
-google-service-account-json="": the path to the service account json credentials
-htpasswd-file="": additionally authenticate against a htpasswd file. Entries must be created with "htpasswd -s" for SHA encryption
-http-address="127.0.0.1:4180": [http://]<addr>:<port> or unix://<path> to listen on for HTTP clients
-https-address=":443": <addr>:<port> to listen on for HTTPS clients
@ -141,7 +165,7 @@ The environment variables `OAUTH2_PROXY_CLIENT_ID`, `OAUTH2_PROXY_CLIENT_SECRET`
## SSL Configuration
There are two recommended configurations.
There are two recommended configurations.
1) Configure SSL Terminiation with OAuth2 Proxy by providing a `--tls-cert=/path/to/cert.pem` and `--tls-key=/path/to/cert.key`.
@ -171,7 +195,7 @@ Nginx will listen on port `443` and handle SSL connections while proxying to `oa
`oauth2_proxy` will then authenticate requests for an upstream application. The external endpoint for this example
would be `https://internal.yourcompany.com/`.
An example Nginx config follows. Note the use of `Strict-Transport-Security` header to pin requests to SSL
An example Nginx config follows. Note the use of `Strict-Transport-Security` header to pin requests to SSL
via [HSTS](http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security):
```
@ -233,4 +257,3 @@ Follow the examples in the [`providers` package](providers/) to define a new
`Provider` instance. Add a new `case` to
[`providers.New()`](providers/providers.go) to allow `oauth2_proxy` to use the
new `Provider`.

4
main.go
View File

@ -20,6 +20,7 @@ func main() {
emailDomains := StringArray{}
upstreams := StringArray{}
skipAuthRegex := StringArray{}
googleGroups := StringArray{}
config := flagSet.String("config", "", "path to config file")
showVersion := flagSet.Bool("version", false, "print version string")
@ -39,6 +40,9 @@ func main() {
flagSet.Var(&emailDomains, "email-domain", "authenticate emails with the specified domain (may be given multiple times). Use * to authenticate any email")
flagSet.String("github-org", "", "restrict logins to members of this organisation")
flagSet.String("github-team", "", "restrict logins to members of this team")
flagSet.Var(&googleGroups, "google-group", "restrict logins to members of this google group (may be given multiple times).")
flagSet.String("google-admin-email", "", "the google admin to impersonate for api calls")
flagSet.String("google-service-account-json", "", "the path to the service account json credentials")
flagSet.String("client-id", "", "the OAuth Client ID: ie: \"123456.apps.googleusercontent.com\"")
flagSet.String("client-secret", "", "the OAuth Client Secret")
flagSet.String("authenticated-emails-file", "", "authenticate against emails via file (one per line)")

6
oauthproxy.go
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@ -433,7 +433,7 @@ func (p *OauthProxy) OauthCallback(rw http.ResponseWriter, req *http.Request) {
}
// set cookie, or deny
if p.Validator(session.Email) {
if p.Validator(session.Email) && p.provider.ValidateGroup(session.Email) {
log.Printf("%s authentication complete %s", remoteAddr, session)
err := p.SaveSession(rw, req, session)
if err != nil {
@ -477,7 +477,7 @@ func (p *OauthProxy) Proxy(rw http.ResponseWriter, req *http.Request) {
clearSession = true
}
if saveSession && !revalidated && session.AccessToken != "" {
if saveSession && !revalidated && session != nil && session.AccessToken != "" {
if !p.provider.ValidateSessionState(session) {
log.Printf("%s removing session. error validating %s", remoteAddr, session)
saveSession = false
@ -493,7 +493,7 @@ func (p *OauthProxy) Proxy(rw http.ResponseWriter, req *http.Request) {
clearSession = true
}
if saveSession {
if saveSession && session != nil {
err := p.SaveSession(rw, req, session)
if err != nil {
log.Printf("%s %s", remoteAddr, err)

39
options.go
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@ -3,6 +3,7 @@ package main
import (
"fmt"
"net/url"
"os"
"regexp"
"strings"
"time"
@ -21,13 +22,16 @@ type Options struct {
TLSCertFile string `flag:"tls-cert" cfg:"tls_cert_file"`
TLSKeyFile string `flag:"tls-key" cfg:"tls_key_file"`
AuthenticatedEmailsFile string `flag:"authenticated-emails-file" cfg:"authenticated_emails_file"`
EmailDomains []string `flag:"email-domain" cfg:"email_domains"`
GitHubOrg string `flag:"github-org" cfg:"github_org"`
GitHubTeam string `flag:"github-team" cfg:"github_team"`
HtpasswdFile string `flag:"htpasswd-file" cfg:"htpasswd_file"`
DisplayHtpasswdForm bool `flag:"display-htpasswd-form" cfg:"display_htpasswd_form"`
CustomTemplatesDir string `flag:"custom-templates-dir" cfg:"custom_templates_dir"`
AuthenticatedEmailsFile string `flag:"authenticated-emails-file" cfg:"authenticated_emails_file"`
EmailDomains []string `flag:"email-domain" cfg:"email_domains"`
GitHubOrg string `flag:"github-org" cfg:"github_org"`
GitHubTeam string `flag:"github-team" cfg:"github_team"`
GoogleGroups []string `flag:"google-group" cfg:"google_group"`
GoogleAdminEmail string `flag:"google-admin-email" cfg:"google_admin_email"`
GoogleServiceAccountJSON string `flag:"google-service-account-json" cfg:"google_service_account_json"`
HtpasswdFile string `flag:"htpasswd-file" cfg:"htpasswd_file"`
DisplayHtpasswdForm bool `flag:"display-htpasswd-form" cfg:"display_htpasswd_form"`
CustomTemplatesDir string `flag:"custom-templates-dir" cfg:"custom_templates_dir"`
CookieName string `flag:"cookie-name" cfg:"cookie_name" env:"OAUTH2_PROXY_COOKIE_NAME"`
CookieSecret string `flag:"cookie-secret" cfg:"cookie_secret" env:"OAUTH2_PROXY_COOKIE_SECRET"`
@ -159,6 +163,18 @@ func (o *Options) Validate() error {
o.CookieExpire.String()))
}
if len(o.GoogleGroups) > 0 || o.GoogleAdminEmail != "" || o.GoogleServiceAccountJSON != "" {
if len(o.GoogleGroups) < 1 {
msgs = append(msgs, "missing setting: google-group")
}
if o.GoogleAdminEmail == "" {
msgs = append(msgs, "missing setting: google-admin-email")
}
if o.GoogleServiceAccountJSON == "" {
msgs = append(msgs, "missing setting: google-service-account-json")
}
}
if len(msgs) != 0 {
return fmt.Errorf("Invalid configuration:\n %s",
strings.Join(msgs, "\n "))
@ -182,6 +198,15 @@ func parseProviderInfo(o *Options, msgs []string) []string {
switch p := o.provider.(type) {
case *providers.GitHubProvider:
p.SetOrgTeam(o.GitHubOrg, o.GitHubTeam)
case *providers.GoogleProvider:
if o.GoogleServiceAccountJSON != "" {
file, err := os.Open(o.GoogleServiceAccountJSON)
if err != nil {
msgs = append(msgs, "invalid Google credentials file: "+o.GoogleServiceAccountJSON)
} else {
p.SetGroupRestriction(o.GoogleGroups, o.GoogleAdminEmail, file)
}
}
}
return msgs
}

26
options_test.go
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@ -40,6 +40,32 @@ func TestNewOptions(t *testing.T) {
assert.Equal(t, expected, err.Error())
}
func TestGoogleGroupOptions(t *testing.T) {
o := testOptions()
o.GoogleGroups = []string{"googlegroup"}
err := o.Validate()
assert.NotEqual(t, nil, err)
expected := errorMsg([]string{
"missing setting: google-admin-email",
"missing setting: google-service-account-json"})
assert.Equal(t, expected, err.Error())
}
func TestGoogleGroupInvalidFile(t *testing.T) {
o := testOptions()
o.GoogleGroups = []string{"test_group"}
o.GoogleAdminEmail = "admin@example.com"
o.GoogleServiceAccountJSON = "file_doesnt_exist.json"
err := o.Validate()
assert.NotEqual(t, nil, err)
expected := errorMsg([]string{
"invalid Google credentials file: file_doesnt_exist.json",
})
assert.Equal(t, expected, err.Error())
}
func TestInitializedOptions(t *testing.T) {
o := testOptions()
assert.Equal(t, nil, o.Validate())

120
providers/google.go
View File

@ -6,17 +6,25 @@ import (
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/url"
"strings"
"time"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"google.golang.org/api/admin/directory/v1"
)
type GoogleProvider struct {
*ProviderData
RedeemRefreshUrl *url.URL
// GroupValidator is a function that determines if the passed email is in
// the configured Google group.
GroupValidator func(string) bool
}
func NewGoogleProvider(p *ProviderData) *GoogleProvider {
@ -42,7 +50,15 @@ func NewGoogleProvider(p *ProviderData) *GoogleProvider {
if p.Scope == "" {
p.Scope = "profile email"
}
return &GoogleProvider{ProviderData: p}
return &GoogleProvider{
ProviderData: p,
// Set a default GroupValidator to just always return valid (true), it will
// be overwritten if we configured a Google group restriction.
GroupValidator: func(email string) bool {
return true
},
}
}
func emailFromIdToken(idToken string) (string, error) {
@ -139,6 +155,102 @@ func (p *GoogleProvider) Redeem(redirectUrl, code string) (s *SessionState, err
return
}
// SetGroupRestriction configures the GoogleProvider to restrict access to the
// specified group(s). AdminEmail has to be an administrative email on the domain that is
// checked. CredentialsFile is the path to a json file containing a Google service
// account credentials.
func (p *GoogleProvider) SetGroupRestriction(groups []string, adminEmail string, credentialsReader io.Reader) {
adminService := getAdminService(adminEmail, credentialsReader)
p.GroupValidator = func(email string) bool {
return userInGroup(adminService, groups, email)
}
}
func getAdminService(adminEmail string, credentialsReader io.Reader) *admin.Service {
data, err := ioutil.ReadAll(credentialsReader)
if err != nil {
log.Fatal("can't read Google credentials file:", err)
}
conf, err := google.JWTConfigFromJSON(data, admin.AdminDirectoryUserReadonlyScope, admin.AdminDirectoryGroupReadonlyScope)
if err != nil {
log.Fatal("can't load Google credentials file:", err)
}
conf.Subject = adminEmail
client := conf.Client(oauth2.NoContext)
adminService, err := admin.New(client)
if err != nil {
log.Fatal(err)
}
return adminService
}
func userInGroup(service *admin.Service, groups []string, email string) bool {
user, err := fetchUser(service, email)
if err != nil {
log.Printf("error fetching user: %v", err)
return false
}
id := user.Id
custID := user.CustomerId
for _, group := range groups {
members, err := fetchGroupMembers(service, group)
if err != nil {
log.Printf("error fetching group members: %v", err)
return false
}
for _, member := range members {
switch member.Type {
case "CUSTOMER":
if member.Id == custID {
return true
}
case "USER":
if member.Id == id {
return true
}
}
}
}
return false
}
func fetchUser(service *admin.Service, email string) (*admin.User, error) {
user, err := service.Users.Get(email).Do()
return user, err
}
func fetchGroupMembers(service *admin.Service, group string) ([]*admin.Member, error) {
members := []*admin.Member{}
pageToken := ""
for {
req := service.Members.List(group)
if pageToken != "" {
req.PageToken(pageToken)
}
r, err := req.Do()
if err != nil {
return nil, err
}
for _, member := range r.Members {
members = append(members, member)
}
if r.NextPageToken == "" {
break
}
pageToken = r.NextPageToken
}
return members, nil
}
// ValidateGroup validates that the provided email exists in the configured Google
// group(s).
func (p *GoogleProvider) ValidateGroup(email string) bool {
return p.GroupValidator(email)
}
func (p *GoogleProvider) RefreshSessionIfNeeded(s *SessionState) (bool, error) {
if s == nil || s.ExpiresOn.After(time.Now()) || s.RefreshToken == "" {
return false, nil
@ -148,6 +260,12 @@ func (p *GoogleProvider) RefreshSessionIfNeeded(s *SessionState) (bool, error) {
if err != nil {
return false, err
}
// re-check that the user is in the proper google group(s)
if !p.ValidateGroup(s.Email) {
return false, fmt.Errorf("%s is no longer in the group(s)", s.Email)
}
origExpiration := s.ExpiresOn
s.AccessToken = newToken
s.ExpiresOn = time.Now().Add(duration).Truncate(time.Second)

17
providers/google_test.go
View File

@ -105,6 +105,23 @@ func TestGoogleProviderGetEmailAddress(t *testing.T) {
assert.Equal(t, "refresh12345", session.RefreshToken)
}
func TestGoogleProviderValidateGroup(t *testing.T) {
p := newGoogleProvider()
p.GroupValidator = func(email string) bool {
return email == "michael.bland@gsa.gov"
}
assert.Equal(t, true, p.ValidateGroup("michael.bland@gsa.gov"))
p.GroupValidator = func(email string) bool {
return email != "michael.bland@gsa.gov"
}
assert.Equal(t, false, p.ValidateGroup("michael.bland@gsa.gov"))
}
func TestGoogleProviderWithoutValidateGroup(t *testing.T) {
p := newGoogleProvider()
assert.Equal(t, true, p.ValidateGroup("michael.bland@gsa.gov"))
}
//
func TestGoogleProviderGetEmailAddressInvalidEncoding(t *testing.T) {
p := newGoogleProvider()

6
providers/provider_default.go
View File

@ -105,6 +105,12 @@ func (p *ProviderData) GetEmailAddress(s *SessionState) (string, error) {
return "", errors.New("not implemented")
}
// ValidateGroup validates that the provided email exists in the configured provider
// email group(s).
func (p *ProviderData) ValidateGroup(email string) bool {
return true
}
func (p *ProviderData) ValidateSessionState(s *SessionState) bool {
return validateToken(p, s.AccessToken, nil)
}

1
providers/providers.go
View File

@ -8,6 +8,7 @@ type Provider interface {
Data() *ProviderData
GetEmailAddress(*SessionState) (string, error)
Redeem(string, string) (*SessionState, error)
ValidateGroup(string) bool
ValidateSessionState(*SessionState) bool
GetLoginURL(redirectURI, finalRedirect string) string
RefreshSessionIfNeeded(*SessionState) (bool, error)