From f6834c347ad64d2768b60b60f411597a467b4b64 Mon Sep 17 00:00:00 2001
From: tdakkota <tanc13@yandex.ru>
Date: Wed, 20 Mar 2024 22:01:05 +0300
Subject: [PATCH] promql: validate `label_join` destination label

Signed-off-by: tdakkota <tanc13@yandex.ru>
---
 promql/functions.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/promql/functions.go b/promql/functions.go
index da66af2f0..d5840374e 100644
--- a/promql/functions.go
+++ b/promql/functions.go
@@ -1386,6 +1386,9 @@ func (ev *evaluator) evalLabelJoin(args parser.Expressions) (parser.Value, annot
 		}
 		srcLabels[i-3] = src
 	}
+	if !model.LabelName(dst).IsValid() {
+		panic(fmt.Errorf("invalid destination label name in label_join(): %s", dst))
+	}
 
 	val, ws := ev.eval(args[0])
 	matrix := val.(Matrix)