Fixes #2 : Adds Microsoft Azure Active Directory provider support (#5)

authenticate/providers/google.go

@@ -6,12 +6,13 @@ import (
 	"time"
 
 	oidc "github.com/pomerium/go-oidc"
+	"golang.org/x/oauth2"
+
 	"github.com/pomerium/pomerium/authenticate/circuit"
 	"github.com/pomerium/pomerium/internal/httputil"
 	"github.com/pomerium/pomerium/internal/log"
 	"github.com/pomerium/pomerium/internal/sessions"
 	"github.com/pomerium/pomerium/internal/version"
-	"golang.org/x/oauth2"
 )
 
 const defaultGoogleProviderURL = "https://accounts.google.com"

authenticate/providers/microsoft.go

@@ -0,0 +1,110 @@
+package providers // import "github.com/pomerium/pomerium/internal/providers"
+
+import (
+	"context"
+	"net/url"
+	"time"
+
+	oidc "github.com/pomerium/go-oidc"
+	"golang.org/x/oauth2"
+
+	"github.com/pomerium/pomerium/authenticate/circuit"
+	"github.com/pomerium/pomerium/internal/httputil"
+	"github.com/pomerium/pomerium/internal/log"
+	"github.com/pomerium/pomerium/internal/sessions"
+	"github.com/pomerium/pomerium/internal/version"
+)
+
+// defaultAzureProviderURL Users with both a personal Microsoft
+// account and a work or school account from Azure Active Directory (Azure AD)
+// an sign in to the application.
+const defaultAzureProviderURL = "https://login.microsoftonline.com/common"
+
+// AzureProvider is an implementation of the Provider interface
+type AzureProvider struct {
+	*ProviderData
+	cb *circuit.Breaker
+	// non-standard oidc fields
+	RevokeURL *url.URL
+}
+
+// NewAzureProvider returns a new AzureProvider and sets the provider url endpoints.
+// If non-"common" tenant is desired, ProviderURL must be set.
+// https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-protocols-oidc
+func NewAzureProvider(p *ProviderData) (*AzureProvider, error) {
+	ctx := context.Background()
+
+	if p.ProviderURL == "" {
+		p.ProviderURL = defaultAzureProviderURL
+	}
+	log.Info().Msgf("provider url %s", p.ProviderURL)
+	provider, err := oidc.NewProvider(ctx, p.ProviderURL)
+	if err != nil {
+		return nil, err
+	}
+
+	p.verifier = provider.Verifier(&oidc.Config{ClientID: p.ClientID})
+	p.oauth = &oauth2.Config{
+		ClientID:     p.ClientID,
+		ClientSecret: p.ClientSecret,
+		Endpoint:     provider.Endpoint(),
+		RedirectURL:  p.RedirectURL.String(),
+		Scopes:       []string{oidc.ScopeOpenID, "profile", "email"},
+	}
+
+	azureProvider := &AzureProvider{
+		ProviderData: p,
+	}
+	// azure has a "end session endpoint"
+	var claims struct {
+		RevokeURL string `json:"end_session_endpoint"`
+	}
+
+	if err := provider.Claims(&claims); err != nil {
+		return nil, err
+	}
+
+	azureProvider.RevokeURL, err = url.Parse(claims.RevokeURL)
+	if err != nil {
+		return nil, err
+	}
+
+	azureProvider.cb = circuit.NewBreaker(&circuit.Options{
+		HalfOpenConcurrentRequests: 2,
+		OnStateChange:              azureProvider.cbStateChange,
+		OnBackoff:                  azureProvider.cbBackoff,
+		ShouldTripFunc:             func(c circuit.Counts) bool { return c.ConsecutiveFailures >= 3 },
+		ShouldResetFunc:            func(c circuit.Counts) bool { return c.ConsecutiveSuccesses >= 6 },
+		BackoffDurationFunc: circuit.ExponentialBackoffDuration(
+			time.Duration(200)*time.Second,
+			time.Duration(500)*time.Millisecond),
+	})
+
+	return azureProvider, nil
+}
+
+func (p *AzureProvider) cbBackoff(duration time.Duration, reset time.Time) {
+	log.Info().Dur("duration", duration).Msg("authenticate/providers/azure.cbBackoff")
+
+}
+
+func (p *AzureProvider) cbStateChange(from, to circuit.State) {
+	log.Info().Str("from", from.String()).Str("to", to.String()).Msg("authenticate/providers/azure.cbStateChange")
+}
+
+// Revoke revokes the access token a given session state.
+//https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-protocols-oidc#send-a-sign-out-request
+func (p *AzureProvider) Revoke(s *sessions.SessionState) error {
+	params := url.Values{}
+	params.Add("token", s.AccessToken)
+	err := httputil.Client("POST", p.RevokeURL.String(), version.UserAgent(), params, nil)
+	if err != nil && err != httputil.ErrTokenRevoked {
+		return err
+	}
+	return nil
+}
+
+// GetSignInURL returns the sign in url with typical oauth parameters
+func (p *AzureProvider) GetSignInURL(state string) string {
+	return p.oauth.AuthCodeURL(state, oauth2.AccessTypeOffline, oauth2.ApprovalForce)
+}

authenticate/providers/okta.go

@@ -6,10 +6,11 @@ import (
 	"net/url"
 
 	oidc "github.com/pomerium/go-oidc"
+	"golang.org/x/oauth2"
+
 	"github.com/pomerium/pomerium/internal/httputil"
 	"github.com/pomerium/pomerium/internal/sessions"
 	"github.com/pomerium/pomerium/internal/version"
-	"golang.org/x/oauth2"
 )
 
 // OktaProvider provides a standard, OpenID Connect implementation

authenticate/providers/providers.go

@@ -8,12 +8,15 @@ import (
 	"time"
 
 	oidc "github.com/pomerium/go-oidc"
+	"golang.org/x/oauth2"
+
 	"github.com/pomerium/pomerium/internal/log"
 	"github.com/pomerium/pomerium/internal/sessions"
-	"golang.org/x/oauth2"
 )
 
 const (
+	// AzureProviderName identifies the Azure provider
+	AzureProviderName = "azure"
 	// GoogleProviderName identifies the Google provider
 	GoogleProviderName = "google"
 	// OIDCProviderName identifes a generic OpenID connect provider
@@ -44,6 +47,12 @@ func New(provider string, p *ProviderData) (Provider, error) {
 			return nil, err
 		}
 		return p, nil
+	case AzureProviderName:
+		p, err := NewAzureProvider(p)
+		if err != nil {
+			return nil, err
+		}
+		return p, nil
 	case OktaProviderName:
 		p, err := NewOktaProvider(p)
 		if err != nil {