From c71ae9b31034641a31c34b46e3f18c58e37f531f Mon Sep 17 00:00:00 2001
From: DarthVader <61409963+darsvador@users.noreply.github.com>
Date: Tue, 16 Mar 2021 19:07:32 +0800
Subject: [PATCH] Fix: core panics when zero domain/full type of rule (#786)

---
 common/strmatcher/mph_matcher.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/common/strmatcher/mph_matcher.go b/common/strmatcher/mph_matcher.go
index 794d6b8d4..21b98e764 100644
--- a/common/strmatcher/mph_matcher.go
+++ b/common/strmatcher/mph_matcher.go
@@ -94,6 +94,10 @@ func (g *MphMatcherGroup) Build() {
 		g.ac.Build()
 	}
 	keyLen := len(*g.ruleMap)
+	if keyLen == 0 {
+		keyLen = 1
+		(*g.ruleMap)["empty___"] = RollingHash("empty___")
+	}
 	g.level0 = make([]uint32, nextPow2(keyLen/4))
 	g.level0Mask = len(g.level0) - 1
 	g.level1 = make([]uint32, nextPow2(keyLen))