Azure OAuth: Use TID from id_token by default (#56264)

Co-authored-by: Kalle Persson <kalle.persson@grafana.com>

Co-authored-by: Kalle Persson <kalle.persson@grafana.com>

pkg/login/social/azuread_oauth.go

@@ -29,6 +29,7 @@ type azureClaims struct {
 	ID                string                 `json:"oid"`
 	ClaimNames        claimNames             `json:"_claim_names,omitempty"`
 	ClaimSources      map[string]claimSource `json:"_claim_sources,omitempty"`
+	TenantID          string                 `json:"tid,omitempty"`
 }
 
 type claimNames struct {
@@ -177,20 +178,27 @@ func extractGroups(client *http.Client, claims azureClaims, token *oauth2.Token)
 	// If user groups exceeds 200 no groups will be found in claims.
 	// See https://docs.microsoft.com/en-us/azure/active-directory/develop/id-tokens#groups-overage-claim
 	endpoint := claims.ClaimSources[claims.ClaimNames.Groups].Endpoint
+
+	// If the endpoints provided in _claim_source is pointing to the deprecated "graph.windows.net" api
+	// replace with handcrafted url to graph.microsoft.com
+	// See https://docs.microsoft.com/en-us/graph/migrate-azure-ad-graph-overview
 	if strings.Contains(endpoint, "graph.windows.net") {
-		// If the endpoints provided in _claim_source is pointed to the deprecated "graph.windows.net" api
-		// replace with handcrafted url to graph.microsoft.com
-		// See https://docs.microsoft.com/en-us/graph/migrate-azure-ad-graph-overview
-		parsedToken, err := jwt.ParseSigned(token.AccessToken)
-		if err != nil {
-			return nil, fmt.Errorf("error parsing id token: %w", err)
-		}
+		tenantID := claims.TenantID
+		// If tenantID wasn't found in the id_token, parse access token
+		if tenantID == "" {
+			parsedToken, err := jwt.ParseSigned(token.AccessToken)
+			if err != nil {
+				return nil, fmt.Errorf("error parsing access token: %w", err)
+			}
 
-		var accessClaims azureAccessClaims
-		if err := parsedToken.UnsafeClaimsWithoutVerification(&accessClaims); err != nil {
-			return nil, fmt.Errorf("error getting claims from access token: %w", err)
+			var accessClaims azureAccessClaims
+			if err := parsedToken.UnsafeClaimsWithoutVerification(&accessClaims); err != nil {
+				return nil, fmt.Errorf("error getting claims from access token: %w", err)
+			}
+			tenantID = accessClaims.TenantID
 		}
-		endpoint = fmt.Sprintf("https://graph.microsoft.com/v1.0/%s/users/%s/getMemberObjects", accessClaims.TenantID, claims.ID)
+
+		endpoint = fmt.Sprintf("https://graph.microsoft.com/v1.0/%s/users/%s/getMemberObjects", tenantID, claims.ID)
 	}
 
 	data, err := json.Marshal(&getAzureGroupRequest{SecurityEnabledOnly: false})