[release-12.0.1] Apply security patch 357-202503311017.patch (#104493)

Apply security patch 357-202503311017.patch (#104490)

* Sanitize paths before evaluating access to route

* use util.CleanRelativePath

---------

Co-authored-by: Andres Martinez Gotor <andres.martinez@grafana.com>
(cherry picked from commit 1f707d16ed)

Co-authored-by: Yuri Tseretyan <yuriy.tseretyan@grafana.com>

pkg/api/pluginproxy/ds_proxy.go

@@ -300,7 +300,15 @@ func (proxy *DataSourceProxy) validateRequest() error {
 		}
 
 		// route match
-		if !strings.HasPrefix(proxy.proxyPath, route.Path) {
+		r1, err := util.CleanRelativePath(proxy.proxyPath)
+		if err != nil {
+			return err
+		}
+		r2, err := util.CleanRelativePath(route.Path)
+		if err != nil {
+			return err
+		}
+		if !strings.HasPrefix(r1, r2) {
 			continue
 		}