Fix: Propagate OIDC claims for dynamic IAM policies (#8060)

Fix: Propagate OIDC claims to IAM identity for dynamic policy variables

Fixes #8037. Ensures additional OIDC claims (like preferred_username) are preserved in ExternalIdentity attributes and propagated to IAM tokens, enabling substitution in dynamic policies.

weed/iam/oidc/oidc_provider.go

@@ -237,6 +237,34 @@ func (p *OIDCProvider) Authenticate(ctx context.Context, token string) (*provide
 		attributes["roles"] = strings.Join(roles, ",")
 	}
 
+	// Store all additional claims as attributes
+	processedClaims := map[string]struct{}{
+		// user / business claims already handled elsewhere
+		"sub":    {},
+		"email":  {},
+		"name":   {},
+		"groups": {},
+		"roles":  {},
+		// standard structural OIDC/JWT claims that should not be exposed as attributes
+		"iss": {},
+		"aud": {},
+		"exp": {},
+		"iat": {},
+		"nbf": {},
+		"jti": {},
+	}
+	for key, value := range claims.Claims {
+		if _, isProcessed := processedClaims[key]; !isProcessed {
+			if strValue, ok := value.(string); ok {
+				attributes[key] = strValue
+			} else if jsonValue, err := json.Marshal(value); err == nil {
+				attributes[key] = string(jsonValue)
+			} else {
+				glog.Warningf("failed to marshal claim %q to JSON for OIDC attributes: %v", key, err)
+			}
+		}
+	}
+
 	identity := &providers.ExternalIdentity{
 		UserID:      claims.Subject,
 		Email:       email,

weed/iam/oidc/oidc_provider_test.go

@@ -248,6 +248,60 @@ func TestOIDCProviderAuthentication(t *testing.T) {
 		assert.Contains(t, identity.Groups, "developers")
 	})
 
+	t.Run("successful authentication with additional attributes", func(t *testing.T) {
+		token := createTestJWT(t, privateKey, jwt.MapClaims{
+			"iss":                server.URL,
+			"aud":                "test-client",
+			"sub":                "user123",
+			"exp":                time.Now().Add(time.Hour).Unix(),
+			"iat":                time.Now().Unix(),
+			"email":              "user@example.com",
+			"name":               "Test User",
+			"groups":             []string{"users"},
+			"preferred_username": "myusername",                              // Extra claim
+			"department":         "engineering",                             // Extra claim
+			"custom_number":      42,                                        // Non-string claim
+			"custom_avg":         98.6,                                      // Non-string claim
+			"custom_object":      map[string]interface{}{"nested": "value"}, // Nested object claim
+		})
+
+		identity, err := provider.Authenticate(context.Background(), token)
+		require.NoError(t, err)
+		require.NotNil(t, identity)
+
+		// Check standard fields
+		assert.Equal(t, "user123", identity.UserID)
+
+		// Check attributes
+		val, exists := identity.Attributes["preferred_username"]
+		assert.True(t, exists, "preferred_username should be in attributes")
+		assert.Equal(t, "myusername", val)
+
+		val, exists = identity.Attributes["department"]
+		assert.True(t, exists, "department should be in attributes")
+		assert.Equal(t, "engineering", val)
+
+		// Test non-string claims (should be JSON marshaled)
+		val, exists = identity.Attributes["custom_number"]
+		assert.True(t, exists, "custom_number should be in attributes")
+		assert.Equal(t, "42", val)
+
+		val, exists = identity.Attributes["custom_avg"]
+		assert.True(t, exists, "custom_avg should be in attributes")
+		assert.Contains(t, val, "98.6") // JSON number formatting might vary
+
+		val, exists = identity.Attributes["custom_object"]
+		assert.True(t, exists, "custom_object should be in attributes")
+		assert.Contains(t, val, "\"nested\":\"value\"")
+
+		// Verify structural JWT claims are excluded from attributes
+		excludedClaims := []string{"iss", "aud", "exp", "iat"}
+		for _, claim := range excludedClaims {
+			_, exists := identity.Attributes[claim]
+			assert.False(t, exists, "standard claim %s should not be in attributes", claim)
+		}
+	})
+
 	t.Run("authentication with invalid token", func(t *testing.T) {
 		_, err := provider.Authenticate(context.Background(), "invalid-token")
 		assert.Error(t, err)

weed/s3api/s3_iam_middleware.go

@@ -133,20 +133,53 @@ func (s3iam *S3IAMIntegration) AuthenticateJWT(ctx context.Context, r *http.Requ
 			return nil, s3err.ErrAccessDenied
 		}
 
+		// Create claims map and populate with standard claims and attributes
+		claims := make(map[string]interface{}, len(identity.Attributes)+5)
+
+		// Add all attributes from the identity to the claims
+		// This makes attributes like "preferred_username" available for policy substitution
+		for k, v := range identity.Attributes {
+			claims[k] = v
+		}
+
+		// Add standard OIDC fields to claims so they are available as variables
+		// This ensures ${jwt:email}, ${jwt:name}, etc. work as documented in the wiki
+		if identity.Email != "" {
+			claims["email"] = identity.Email
+		}
+		if identity.DisplayName != "" {
+			claims["name"] = identity.DisplayName
+		}
+		if len(identity.Groups) > 0 {
+			claims["groups"] = identity.Groups
+		}
+
+		// Set critical claims explicitly, overwriting any from attributes to ensure correctness.
+		claims["sub"] = identity.UserID
+		claims["role"] = identity.RoleArn
+
+		// Use real email address if available
+		emailAddress := identity.UserID + "@oidc.local"
+		if identity.Email != "" {
+			emailAddress = identity.Email
+		}
+
+		displayName := identity.UserID
+		if identity.DisplayName != "" {
+			displayName = identity.DisplayName
+		}
+
 		// Return IAM identity for OIDC token
 		return &IAMIdentity{
 			Name:         identity.UserID,
 			Principal:    identity.RoleArn,
 			SessionToken: sessionToken,
 			Account: &Account{
-				DisplayName:  identity.UserID,
-				EmailAddress: identity.UserID + "@oidc.local",
+				DisplayName:  displayName,
+				EmailAddress: emailAddress,
 				Id:           identity.UserID,
 			},
-			Claims: map[string]interface{}{
-				"sub":  identity.UserID,
-				"role": identity.RoleArn,
-			},
+			Claims: claims,
 		}, s3err.ErrNone
 	}
 
@@ -655,9 +688,13 @@ func (enhanced *EnhancedS3ApiServer) AuthorizeRequest(r *http.Request, identity
 
 // OIDCIdentity represents an identity validated through OIDC
 type OIDCIdentity struct {
-	UserID   string
-	RoleArn  string
-	Provider string
+	UserID      string
+	RoleArn     string
+	Provider    string
+	Email       string
+	DisplayName string
+	Groups      []string
+	Attributes  map[string]string
 }
 
 // validateExternalOIDCToken validates an external OIDC token using the STS service's secure issuer-based lookup
@@ -714,9 +751,13 @@ func (s3iam *S3IAMIntegration) validateExternalOIDCToken(ctx context.Context, to
 	roleArn := s3iam.selectPrimaryRole(cleanRoles, externalIdentity)
 
 	return &OIDCIdentity{
-		UserID:   externalIdentity.UserID,
-		RoleArn:  roleArn,
-		Provider: fmt.Sprintf("%T", provider), // Use provider type as identifier
+		UserID:      externalIdentity.UserID,
+		RoleArn:     roleArn,
+		Provider:    fmt.Sprintf("%T", provider), // Use provider type as identifier
+		Email:       externalIdentity.Email,
+		DisplayName: externalIdentity.DisplayName,
+		Groups:      externalIdentity.Groups,
+		Attributes:  externalIdentity.Attributes,
 	}, nil
 }