refactor: ensure only a given install can access its access tokens with the app-install-get-access-token route

api/middleware.go

@@ -15,6 +15,7 @@ import (
 	"gorm.io/gorm"
 	"io"
 	"net/http"
+	"strconv"
 	"strings"
 )
 
@@ -128,6 +129,21 @@ func githubRestVerifyMiddleware(db *gorm.DB) mux.MiddlewareFunc {
 					http.Error(w, err.Error(), http.StatusBadRequest)
 					return
 				}
+
+				if mux.CurrentRoute(r).GetName() == "app-install-get-access-token" {
+					installId := mux.Vars(r)["installation_id"]
+
+					installIdInt, err := strconv.Atoi(installId)
+					if err != nil {
+						http.Error(w, "Invalid Install", http.StatusUnauthorized)
+						return
+					}
+
+					if appId != uint(installIdInt) {
+						http.Error(w, "Invalid Install", http.StatusUnauthorized)
+						return
+					}
+				}
 			}
 
 			addAuthStatusToRequestServ(true, r, w, next)