Implement configurable OIDC claims extraction (#44)

This PR expands the authentication agent with methods to extract an OAuth2 token claims and set their values to HAProxy session variables.

The token claims are prefixed with "token_claim_" and can be used as in an example below:

```
http-request set-header X-OIDC-Username %[var(sess.auth.token_claim_name)] if acl_app3 authenticated
```
---------

Signed-off-by: Dmitrii Ermakov <dmitrii.ermakov@maxiv.lu.se>
Co-authored-by: Dmitrii Ermakov <dmitrii.ermakov@maxiv.lu.se>

Author: ErmakovDmitriy

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/spf13/viper v1.19.0
 	github.com/stretchr/testify v1.9.0
 	github.com/tebeka/selenium v0.9.9
+	github.com/tidwall/gjson v1.17.1
 	github.com/vmihailenco/msgpack/v5 v5.4.1
 	golang.org/x/oauth2 v0.21.0
 )
@@ -34,6 +35,8 @@ require (
 	github.com/spf13/cast v1.6.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/subosito/gotenv v1.6.0 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.0 // indirect
 	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
 	go.uber.org/atomic v1.9.0 // indirect
 	go.uber.org/multierr v1.9.0 // indirect

go.sum

@@ -126,6 +126,12 @@ github.com/subosito/gotenv v1.6.0 h1:9NlTDc1FTs4qu0DDq7AEtTPNw6SVm7uBMsUCUjABIf8
 github.com/subosito/gotenv v1.6.0/go.mod h1:Dk4QP5c2W3ibzajGcXpNraDfq2IrhjMIvMSWPKKo0FU=
 github.com/tebeka/selenium v0.9.9 h1:cNziB+etNgyH/7KlNI7RMC1ua5aH1+5wUlFQyzeMh+w=
 github.com/tebeka/selenium v0.9.9/go.mod h1:5Fr8+pUvU6B1OiPfkdCKdXZyr5znvVkxuPd0NOdZCQc=
+github.com/tidwall/gjson v1.17.1 h1:wlYEnwqAHgzmhNUFfw7Xalt2JzQvsMx2Se4PcoFCT/U=
+github.com/tidwall/gjson v1.17.1/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/match v1.1.1 h1:+Ho715JplO36QYgwN9PGYNhgZvoUSc9X2c80KVTi+GA=
+github.com/tidwall/match v1.1.1/go.mod h1:eRSPERbgtNPcGhD8UCthc6PmLEQXEWd3PRB5JTxsfmM=
+github.com/tidwall/pretty v1.2.0 h1:RWIZEg2iJ8/g6fDDYzMpobmaoGh5OLl4AXtGUGPcqCs=
+github.com/tidwall/pretty v1.2.0/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
 github.com/vmihailenco/msgpack/v5 v5.4.1 h1:cQriyiUvjTwOHg8QZaPihLWeRAAVoCpE00IUPn0Bjt8=
 github.com/vmihailenco/msgpack/v5 v5.4.1/go.mod h1:GaZTsDaehaPpQVyxrf5mtQlH+pc21PIudVV/E3rRQok=
 github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAhO7/IwNM9g=

internal/auth/aes_encryptor.go

@@ -68,7 +68,7 @@ func (ae *AESEncryptor) Decrypt(securemess string) (string, error) {
 
 	ciphertextAndNonce, err := base64.StdEncoding.DecodeString(securemess)
 	if err != nil {
-		return "", fmt.Errorf("unable to b64 decode secure message: %v", err)
+		return "", fmt.Errorf("unable to b64 decode secure message: %w", err)
 	}
 
 	block, err := aes.NewCipher(ae.Key)

internal/auth/authenticator_oidc.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/base64"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"net/http"
 	"strings"
@@ -79,13 +80,14 @@ type OIDCAuthenticator struct {
 }
 
 type OAuthArgs struct {
-	ssl bool
-	host string
-	pathq string
-	clientid string
+	ssl          bool
+	host         string
+	pathq        string
+	clientid     string
 	clientsecret string
-	redirecturl string
-	cookie string
+	redirecturl  string
+	cookie       string
+	tokenClaims  []string
 }
 
 // NewOIDCAuthenticator create an instance of an OIDC authenticator
@@ -126,14 +128,14 @@ func NewOIDCAuthenticator(options OIDCAuthenticatorOptions) *OIDCAuthenticator {
 		http.HandleFunc(options.LogoutPath, oa.handleOAuth2Logout())
 		logrus.Infof("OIDC API is exposed on %s", options.CallbackAddr)
 		http.HandleFunc(options.HealthCheckPath, handleHealthCheck)
-		http.ListenAndServe(options.CallbackAddr, nil)
+		logrus.Fatalln(http.ListenAndServe(options.CallbackAddr, nil))
 	}()
 
 	return oa
 }
 
 func handleHealthCheck(w http.ResponseWriter, r *http.Request) {
-	w.Write([]byte("OK"))
+	_, _ = w.Write([]byte("OK"))
 }
 
 func (oa *OIDCAuthenticator) withOAuth2Config(domain string, callback func(c oauth2.Config) error) error {
@@ -166,24 +168,25 @@ func (oa *OIDCAuthenticator) verifyIDToken(context context.Context, domain strin
 	// Parse and verify ID Token payload.
 	idToken, err := verifier.Verify(context, rawIDToken)
 	if err != nil {
-		return nil, fmt.Errorf("unable to verify ID Token: %v", err)
+		return nil, fmt.Errorf("unable to verify ID Token: %w", err)
 	}
 	return idToken, nil
 }
 
-func (oa *OIDCAuthenticator) checkCookie(cookieValue string, domain string) error {
+func (oa *OIDCAuthenticator) decryptCookie(cookieValue string, domain string) (*oidc.IDToken, error) {
 	idToken, err := oa.encryptor.Decrypt(cookieValue)
 	if err != nil {
-		return fmt.Errorf("unable to decrypt session cookie: %v", err)
+		return nil, fmt.Errorf("unable to decrypt session cookie: %w", err)
 	}
 
-	_, err = oa.verifyIDToken(context.Background(), domain, idToken)
-	return err
+	token, err := oa.verifyIDToken(context.Background(), domain, idToken)
+	return token, err
 }
 
 func extractOAuth2Args(msg *message.Message, readClientInfoFromMessages bool) (OAuthArgs, error) {
 	var cookie string
 	var clientid, clientsecret, redirecturl *string
+	var tokenClaims []string
 
 	// ssl
 	sslValue, ok := msg.KV.Get("arg_ssl")
@@ -225,6 +228,15 @@ func extractOAuth2Args(msg *message.Message, readClientInfoFromMessages bool) (O
 	cookieValue, ok := msg.KV.Get("arg_cookie")
 	if ok {
 		cookie, _ = cookieValue.(string)
+
+		// Token claims
+		tokenClaimsValue, ok := msg.KV.Get("arg_token_claims")
+		if ok {
+			strV, ok := tokenClaimsValue.(string)
+			if ok {
+				tokenClaims = strings.Split(strV, " ")
+			}
+		}
 	}
 
 	if readClientInfoFromMessages {
@@ -281,8 +293,9 @@ func extractOAuth2Args(msg *message.Message, readClientInfoFromMessages bool) (O
 		clientsecret = &temp
 	}
 	return OAuthArgs{ssl: ssl, host: host, pathq: pathq,
-					 cookie: cookie, clientid: *clientid,
-					 clientsecret: *clientsecret, redirecturl: *redirecturl},
+			cookie: cookie, clientid: *clientid,
+			clientsecret: *clientsecret, redirecturl: *redirecturl,
+			tokenClaims: tokenClaims},
 		nil
 }
 
@@ -328,14 +341,47 @@ func (oa *OIDCAuthenticator) Authenticate(msg *message.Message) (bool, []action.
 
 	// Verify the cookie to make sure the user is authenticated
 	if oauthArgs.cookie != "" {
-		err := oa.checkCookie(oauthArgs.cookie, extractDomainFromHost(oauthArgs.host))
+		idToken, err := oa.decryptCookie(oauthArgs.cookie, domain)
 		if err != nil {
+			// CoreOS/go-oidc does not have error types, so the errors are handled using strings
+			// comparison.
+			if errors.Is(err, &oidc.TokenExpiredError{}) || strings.Contains(err.Error(), "oidc:") {
+				authorizationURL, e := oa.buildAuthorizationURL(domain, oauthArgs)
+				if e != nil {
+					return false, nil, e
+				}
+
+				logrus.Infof("Authentication failed, redirecting to OIDC provider %s, reason: %s", authorizationURL, err)
+
+				return false, []action.Action{BuildRedirectURLMessage(authorizationURL)}, nil
+			}
+
 			return false, nil, err
-		} else {
+		}
+
+		if len(oauthArgs.tokenClaims) == 0 {
 			return true, nil, nil
+		} else {
+			// Extract token claims.
+			actions, err := BuildTokenClaimsMessage(idToken, oauthArgs.tokenClaims)
+			if err != nil {
+				return false, nil, err
+			}
+
+			return true, actions, nil
 		}
+
 	}
 
+	authorizationURL, err := oa.buildAuthorizationURL(domain, oauthArgs)
+	if err != nil {
+		return false, nil, err
+	}
+
+	return false, []action.Action{BuildRedirectURLMessage(authorizationURL)}, nil
+}
+
+func (oa *OIDCAuthenticator) buildAuthorizationURL(domain string, oauthArgs OAuthArgs) (string, error) {
 	currentTime := time.Now()
 
 	var state State
@@ -346,7 +392,7 @@ func (oa *OIDCAuthenticator) Authenticate(msg *message.Message) (bool, []action.
 
 	stateBytes, err := msgpack.Marshal(state)
 	if err != nil {
-		return false, nil, fmt.Errorf("unable to marshal the state")
+		return "", fmt.Errorf("unable to marshal the state")
 	}
 
 	var authorizationURL string
@@ -355,10 +401,10 @@ func (oa *OIDCAuthenticator) Authenticate(msg *message.Message) (bool, []action.
 		return nil
 	})
 	if err != nil {
-		return false, nil, fmt.Errorf("unable to build authorize url: %w", err)
+		return "", fmt.Errorf("unable to build authorize url: %w", err)
 	}
 
-	return false, []action.Action{BuildRedirectURLMessage(authorizationURL)}, nil
+	return authorizationURL, nil
 }
 
 func (oa *OIDCAuthenticator) handleOAuth2Logout() http.HandlerFunc {

internal/auth/messages.go

@@ -1,6 +1,14 @@
 package auth
 
-import action "github.com/negasus/haproxy-spoe-go/action"
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+	action "github.com/negasus/haproxy-spoe-go/action"
+	"github.com/tidwall/gjson"
+)
 
 // BuildRedirectURLMessage build a message containing the URL the user should be redirected too
 func BuildRedirectURLMessage(url string) action.Action {
@@ -16,3 +24,70 @@ func BuildHasErrorMessage() action.Action {
 func AuthenticatedUserMessage(username string) action.Action {
 	return action.NewSetVar(action.ScopeSession, "authenticated_user", username)
 }
+
+func BuildTokenClaimsMessage(idToken *oidc.IDToken, claimsFilter []string) ([]action.Action, error) {
+	var claimsData json.RawMessage
+
+	if err := idToken.Claims(&claimsData); err != nil {
+		return nil, fmt.Errorf("unable to load OIDC claims: %w", err)
+	}
+
+	claimsVals := gjson.ParseBytes(claimsData)
+	result := make([]action.Action, 0, len(claimsFilter))
+
+	for i := range claimsFilter {
+		value := claimsVals.Get(claimsFilter[i])
+
+		if !value.Exists() {
+			continue
+		}
+
+		key := computeSPOEKey(claimsFilter[i])
+		result = append(result, action.NewSetVar(action.ScopeSession, key, gjsonToSPOEValue(&value)))
+	}
+
+	return result, nil
+}
+
+var spoeKeyReplacer = strings.NewReplacer("-", "_", ".", "_")
+
+func computeSPOEKey(key string) string {
+	return "token_claim_" + spoeKeyReplacer.Replace(key)
+}
+
+func gjsonToSPOEValue(value *gjson.Result) interface{} {
+	switch value.Type {
+	case gjson.Null:
+		// Null is a null json value
+		return nil
+
+	case gjson.Number:
+		// Number is json number
+		return value.Int()
+
+	case gjson.String:
+		// String is a json string
+		return value.String()
+
+	default:
+		if value.IsArray() {
+			// Make a comma separated list.
+			tmp := value.Array()
+			lastInd := len(tmp) - 1
+			sb := &strings.Builder{}
+
+			for i := 0; i <= lastInd; i++ {
+				sb.WriteString(tmp[i].String())
+
+				if i != lastInd {
+					sb.WriteRune(',')
+				}
+			}
+
+			return sb.String()
+		}
+
+		// Other types such as True, False, JSON.
+		return value.String()
+	}
+}

resources/configuration/config.yml

@@ -14,7 +14,7 @@ ldap:
   # The DN and password of the user to bind with in order to perform the search query to find the user
   user_dn: cn=admin,dc=example,dc=com
   password: password
-  # The base DN used for the search queries 
+  # The base DN used for the search queries
   base_dn: dc=example,dc=com
   # The filter for the query searching for the user provided
   user_filter: "(&(cn={login})(ou:dn:={group}))"
@@ -36,6 +36,7 @@ oidc:
   # Various properties of the cookie holding the ID Token of the user
   cookie_name: authsession
   cookie_secure: false
+  # If not set, then uses ID token expire timestamp
   cookie_ttl_seconds: 3600
   # The secret used to sign the state parameter
   signature_secret: myunsecuresecret

resources/haproxy/haproxy.cfg

@@ -32,6 +32,11 @@ frontend haproxynode
     http-request set-var(req.oidc_client_id) str(app3-client) if acl_app3
     http-request set-var(req.oidc_client_secret) str(app3-secret) if acl_app3
     http-request set-var(req.oidc_redirect_url) str(http://app3.example.com:9080/oauth2/callback) if acl_app3
+    ## Request extra OpenID token claims, space separated
+    ## The extra claims will be set as variables with keys: "token_claim_" + {{ claim name }},
+    ## where '.' and '-' are replaced with '_'.
+    ## Nested claims are supported.
+    http-request set-var(req.oidc_token_claims) str("name roles org-groups resource_access.servicename.roles") if acl_app3
 
     acl oauth2callback path_beg /oauth2/callback
     acl oauth2logout path_beg /oauth2/logout
@@ -58,6 +63,12 @@ frontend haproxynode
     use_backend backend_redirect if acl_app2 ! authenticated
     use_backend backend_app if acl_app2 authenticated
 
+    # Set headers based on OpenID token claims
+    http-request set-header X-OIDC-Username %[var(sess.auth.token_claim_name)] if acl_app3 authenticated
+    http-request set-header X-OIDC-Roles %[var(sess.auth.token_claim_roles)] if acl_app3 authenticated
+    http-request set-header X-OIDC-Groups %[var(sess.auth.token_claim_org_groups)] if acl_app3 authenticated
+    http-request set-header X-OIDC-Resource-Access %[var(sess.auth.token_claim_resource_access_servicename_roles)] if acl_app3 authenticated
+
     # app3 redirects the user to the OAuth2 server when not authenticated
     use_backend backend_redirect if acl_app3 ! authenticated
     use_backend backend_app if acl_app3 authenticated

resources/haproxy/spoe-auth.conf

@@ -18,5 +18,5 @@ spoe-message try-auth-ldap
     event on-frontend-http-request if { hdr_beg(host) -i app1.example.com } || { hdr_beg(host) -i app2.example.com } || { hdr_beg(host) -i app3.example.com }
 
 spoe-message try-auth-oidc
-    args arg_ssl=ssl_fc arg_host=req.hdr(Host) arg_pathq=pathq arg_cookie=req.cook(authsession) arg_client_id=var(req.oidc_client_id) arg_client_secret=var(req.oidc_client_secret) arg_redirect_url=var(req.oidc_redirect_url)
+    args arg_ssl=ssl_fc arg_host=req.hdr(Host) arg_pathq=pathq arg_cookie=req.cook(authsession) arg_client_id=var(req.oidc_client_id) arg_client_secret=var(req.oidc_client_secret) arg_redirect_url=var(req.oidc_redirect_url) arg_token_claims=var(req.oidc_token_claims)
     event on-frontend-http-request if { hdr_beg(host) -i app1.example.com } || { hdr_beg(host) -i app2.example.com } || { hdr_beg(host) -i app3.example.com }