Alerting: Fix per-receiver RBAC for receivers with long names (#95084)

* Implement uidToResourceID

* add middleware

* Move uidToResourceID to alerting package

* Only hash uid if it's too long

* Use hashed uid in access control

* Move ReceiverUidToResourceId to ScopeProvider

* resolve uid in middleware only if param exists

* Tests

* Linting

---------

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

pkg/services/accesscontrol/resourcepermissions/api.go

@@ -5,16 +5,18 @@ import (
 	"net/http"
 	"strconv"
 
+	"go.opentelemetry.io/otel"
+
 	"github.com/grafana/grafana/pkg/api/dtos"
 	"github.com/grafana/grafana/pkg/api/response"
 	"github.com/grafana/grafana/pkg/api/routing"
 	"github.com/grafana/grafana/pkg/services/accesscontrol"
 	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
+	alertingac "github.com/grafana/grafana/pkg/services/ngalert/accesscontrol"
 	"github.com/grafana/grafana/pkg/services/org"
 	"github.com/grafana/grafana/pkg/services/team"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/web"
-	"go.opentelemetry.io/otel"
 )
 
 var tracer = otel.Tracer("github.com/grafana/grafana/pkg/accesscontrol/resourcepermissions")
@@ -48,6 +50,9 @@ func (a *api) registerEndpoints() {
 	if a.service.options.Resource == "teams" {
 		teamUIDResolverResource = team.MiddlewareTeamUIDResolver(a.service.teamService, ":resourceID")
 	}
+	if a.service.options.Resource == "receivers" {
+		teamUIDResolverResource = MiddlewareReceiverUIDResolver(":resourceID")
+	}
 
 	a.router.Group(fmt.Sprintf("/api/access-control/%s", a.service.options.Resource), func(r routing.RouteRegister) {
 		actionRead := fmt.Sprintf("%s.permissions:read", a.service.options.Resource)
@@ -430,3 +435,13 @@ func permissionSetResponse(cmd setPermissionCommand) response.Response {
 	}
 	return response.Success(message)
 }
+
+func MiddlewareReceiverUIDResolver(paramName string) web.Handler {
+	return func(c *contextmodel.ReqContext) {
+		gotParams := web.Params(c.Req)
+		if uid, ok := gotParams[paramName]; ok {
+			gotParams[paramName] = alertingac.ScopeReceiversProvider.GetResourceIDFromUID(uid)
+			web.SetURLParams(c.Req, gotParams)
+		}
+	}
+}