Only allow access request deletion through static roles' permissions (#…

…9540)

* Only allow access request deletion through static roles' permissions

* Test coverage for access request deletion

lib/auth/auth_with_roles.go

@@ -93,6 +93,23 @@ func (a *ServerWithRoles) withOptions(opts ...actionOption) actionConfig {
 	return cfg
 }
 
+func (a *ServerWithRoles) withStaticRoles() (actionConfig, error) {
+	user, err := a.authServer.GetUser(a.context.User.GetName(), false)
+	if err != nil {
+		return actionConfig{}, trace.Wrap(err)
+	}
+
+	checker, err := services.FetchRoles(user.GetRoles(), a.authServer, user.GetTraits())
+	if err != nil {
+		return actionConfig{}, trace.Wrap(err)
+	}
+
+	return actionConfig{context: Context{
+		User:    user,
+		Checker: checker,
+	}}, nil
+}
+
 func (c actionConfig) action(namespace, resource string, verbs ...string) error {
 	if len(verbs) == 0 {
 		return trace.BadParameter("no verbs provided for authorization check on resource %q", resource)
@@ -1385,7 +1402,17 @@ func (a *ServerWithRoles) getProxyPublicAddr() string {
 }
 
 func (a *ServerWithRoles) DeleteAccessRequest(ctx context.Context, name string) error {
-	if err := a.action(apidefaults.Namespace, types.KindAccessRequest, types.VerbDelete); err != nil {
+	cfg, err := a.withStaticRoles()
+	if err != nil {
+		return err
+	}
+	if err := cfg.action(apidefaults.Namespace, types.KindAccessRequest, types.VerbDelete); err != nil {
+		if trace.IsAccessDenied(err) {
+			if a.withOptions(quietAction(true)).action(apidefaults.Namespace, types.KindAccessRequest, types.VerbDelete) == nil {
+				// the user would've had permission with the roles granted by access requests
+				return trace.WrapWithMessage(err, "access request deletion through elevated roles is not allowed")
+			}
+		}
 		return trace.Wrap(err)
 	}
 	return a.authServer.DeleteAccessRequest(ctx, name)

lib/auth/auth_with_roles_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/gravitational/teleport/api/defaults"
 	"github.com/gravitational/teleport/api/types"
 	libdefaults "github.com/gravitational/teleport/lib/defaults"
+	"github.com/gravitational/teleport/lib/services"
 	"github.com/gravitational/teleport/lib/tlsca"
 
 	"github.com/google/go-cmp/cmp"
@@ -1233,3 +1234,91 @@ func TestKindClusterConfig(t *testing.T) {
 		}
 	})
 }
+
+func TestNoElevatedAccessRequestDeletion(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+
+	srv, err := NewTestAuthServer(TestAuthServerConfig{Dir: t.TempDir()})
+	require.NoError(t, err)
+	t.Cleanup(func() { srv.Close() })
+
+	deleterRole, err := types.NewRole("deleter", types.RoleSpecV4{
+		Allow: types.RoleConditions{
+			Rules: []types.Rule{{
+				Resources: []string{"access_request"},
+				Verbs:     []string{"delete"},
+			}},
+		},
+	})
+	require.NoError(t, err)
+	deleterUser, err := CreateUser(srv.AuthServer, "deletey", deleterRole)
+	require.NoError(t, err)
+
+	requesterRole, err := types.NewRole("requester", types.RoleSpecV4{
+		Allow: types.RoleConditions{
+			Request: &types.AccessRequestConditions{
+				Roles: []string{deleterRole.GetName()},
+			},
+		},
+	})
+	require.NoError(t, err)
+	requesterUser, err := CreateUser(srv.AuthServer, "requesty", requesterRole)
+	require.NoError(t, err)
+
+	request, err := services.NewAccessRequest(requesterUser.GetName(), deleterRole.GetName())
+	require.NoError(t, err)
+	// the request must be for an allowed user/role combination or it will get rejected
+	err = srv.AuthServer.CreateAccessRequest(ctx, request)
+	require.NoError(t, err)
+
+	// requesty has used some other unspecified access request to get the
+	// deleter role in this identity
+	requesterAuthContext, err := srv.Authorizer.Authorize(context.WithValue(ctx,
+		ContextUser,
+		LocalUser{
+			Username: requesterUser.GetName(),
+			Identity: tlsca.Identity{
+				Username: requesterUser.GetName(),
+				Groups:   []string{requesterRole.GetName(), deleterRole.GetName()},
+				// a tlsca.Identity must have a nonempty Traits field or the
+				// roles will be reloaded from the backend during Authorize
+				Traits: map[string][]string{"nonempty": {}},
+			},
+		},
+	))
+	require.NoError(t, err)
+	requesterAuth := &ServerWithRoles{
+		authServer: srv.AuthServer,
+		sessions:   srv.SessionServer,
+		alog:       srv.AuditLog,
+		context:    *requesterAuthContext,
+	}
+
+	err = requesterAuth.DeleteAccessRequest(ctx, request.GetName())
+	require.True(t, trace.IsAccessDenied(err))
+	// matches the message in lib/auth/auth_with_roles.go:(*ServerWithRoles).DeleteAccessRequest()
+	require.Contains(t, err.Error(), "deletion through elevated roles")
+
+	deleterAuthContext, err := srv.Authorizer.Authorize(context.WithValue(ctx,
+		ContextUser,
+		LocalUser{
+			Username: deleterUser.GetName(),
+			Identity: tlsca.Identity{
+				Username: deleterUser.GetName(),
+				Groups:   []string{deleterRole.GetName()},
+				Traits:   map[string][]string{"nonempty": {}},
+			},
+		},
+	))
+	require.NoError(t, err)
+	deleterAuth := &ServerWithRoles{
+		authServer: srv.AuthServer,
+		sessions:   srv.SessionServer,
+		alog:       srv.AuditLog,
+		context:    *deleterAuthContext,
+	}
+
+	err = deleterAuth.DeleteAccessRequest(ctx, request.GetName())
+	require.NoError(t, err)
+}