142 lines
3.6 KiB
Go
142 lines
3.6 KiB
Go
package providers
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import (
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"context"
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"fmt"
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"time"
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"golang.org/x/oauth2"
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oidc "github.com/coreos/go-oidc"
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)
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// OIDCProvider represents an OIDC based Identity Provider
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type OIDCProvider struct {
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*ProviderData
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Verifier *oidc.IDTokenVerifier
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}
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// NewOIDCProvider initiates a new OIDCProvider
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func NewOIDCProvider(p *ProviderData) *OIDCProvider {
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p.ProviderName = "OpenID Connect"
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return &OIDCProvider{ProviderData: p}
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}
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// Redeem exchanges the OAuth2 authentication token for an ID token
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func (p *OIDCProvider) Redeem(redirectURL, code string) (s *SessionState, err error) {
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ctx := context.Background()
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c := oauth2.Config{
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ClientID: p.ClientID,
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ClientSecret: p.ClientSecret,
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Endpoint: oauth2.Endpoint{
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TokenURL: p.RedeemURL.String(),
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},
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RedirectURL: redirectURL,
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}
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token, err := c.Exchange(ctx, code)
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if err != nil {
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return nil, fmt.Errorf("token exchange: %v", err)
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}
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s, err = p.createSessionState(ctx, token)
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if err != nil {
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return nil, fmt.Errorf("unable to update session: %v", err)
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}
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return
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}
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// RefreshSessionIfNeeded checks if the session has expired and uses the
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// RefreshToken to fetch a new ID token if required
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func (p *OIDCProvider) RefreshSessionIfNeeded(s *SessionState) (bool, error) {
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if s == nil || s.ExpiresOn.After(time.Now()) || s.RefreshToken == "" {
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return false, nil
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}
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origExpiration := s.ExpiresOn
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err := p.redeemRefreshToken(s)
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if err != nil {
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return false, fmt.Errorf("unable to redeem refresh token: %v", err)
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}
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fmt.Printf("refreshed id token %s (expired on %s)\n", s, origExpiration)
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return true, nil
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}
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func (p *OIDCProvider) redeemRefreshToken(s *SessionState) (err error) {
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c := oauth2.Config{
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ClientID: p.ClientID,
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ClientSecret: p.ClientSecret,
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Endpoint: oauth2.Endpoint{
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TokenURL: p.RedeemURL.String(),
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},
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}
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ctx := context.Background()
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t := &oauth2.Token{
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RefreshToken: s.RefreshToken,
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Expiry: time.Now().Add(-time.Hour),
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}
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token, err := c.TokenSource(ctx, t).Token()
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if err != nil {
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return fmt.Errorf("failed to get token: %v", err)
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}
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newSession, err := p.createSessionState(ctx, token)
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if err != nil {
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return fmt.Errorf("unable to update session: %v", err)
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}
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s.AccessToken = newSession.AccessToken
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s.IDToken = newSession.IDToken
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s.RefreshToken = newSession.RefreshToken
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s.ExpiresOn = newSession.ExpiresOn
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s.Email = newSession.Email
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return
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}
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func (p *OIDCProvider) createSessionState(ctx context.Context, token *oauth2.Token) (*SessionState, error) {
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rawIDToken, ok := token.Extra("id_token").(string)
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if !ok {
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return nil, fmt.Errorf("token response did not contain an id_token")
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}
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// Parse and verify ID Token payload.
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idToken, err := p.Verifier.Verify(ctx, rawIDToken)
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if err != nil {
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return nil, fmt.Errorf("could not verify id_token: %v", err)
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}
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// Extract custom claims.
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var claims struct {
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Email string `json:"email"`
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Verified *bool `json:"email_verified"`
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}
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if err := idToken.Claims(&claims); err != nil {
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return nil, fmt.Errorf("failed to parse id_token claims: %v", err)
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}
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if claims.Email == "" {
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return nil, fmt.Errorf("id_token did not contain an email")
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}
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if claims.Verified != nil && !*claims.Verified {
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return nil, fmt.Errorf("email in id_token (%s) isn't verified", claims.Email)
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}
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return &SessionState{
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AccessToken: token.AccessToken,
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IDToken: rawIDToken,
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RefreshToken: token.RefreshToken,
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ExpiresOn: token.Expiry,
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Email: claims.Email,
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}, nil
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}
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// ValidateSessionState checks that the session's IDToken is still valid
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func (p *OIDCProvider) ValidateSessionState(s *SessionState) bool {
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ctx := context.Background()
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_, err := p.Verifier.Verify(ctx, s.IDToken)
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if err != nil {
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return false
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}
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return true
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}
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