From 8b79b6952460b15e923d55d9e088bf7431784deb Mon Sep 17 00:00:00 2001
From: lionsoul2014 <chenxin619315@gmail.com>
Date: Tue, 19 May 2026 19:43:51 +0800
Subject: [PATCH] fix Index overflow for the cidr parse with bits equals to IP
 max bits

---
 maker/golang/xdb/util.go      |  9 ++++++++-
 maker/golang/xdb/util_test.go | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/maker/golang/xdb/util.go b/maker/golang/xdb/util.go
index e2c5667..aca0143 100644
--- a/maker/golang/xdb/util.go
+++ b/maker/golang/xdb/util.go
@@ -65,7 +65,14 @@ func CIDR2Range(cidrStr string) ([]byte, []byte, error) {
 
 	// border byte rest bit filled with 1
 	byteIdx := bits / 8
-	eip[byteIdx] |= bitMaskList[bits-(byteIdx*8)]
+
+	// check and fill the border byte bits.
+	// @Note this check is possible since there will be bits
+	// like 32 in IPv4 and 128 in IPv6.
+	// fmt.Printf("%s -> bits=%d, byteIdx=%d, maskIdx=%d\n", cidrStr, bits, byteIdx, bits-byteIdx*8)
+	if byteIdx < ipl {
+		eip[byteIdx] |= bitMaskList[bits-(byteIdx*8)]
+	}
 
 	// fill all the rest bits with 1
 	for bi := byteIdx + 1; bi < ipl; bi++ {
diff --git a/maker/golang/xdb/util_test.go b/maker/golang/xdb/util_test.go
index 296c506..f42f27f 100644
--- a/maker/golang/xdb/util_test.go
+++ b/maker/golang/xdb/util_test.go
@@ -364,3 +364,19 @@ func TestCIDR2Range(t *testing.T) {
 		fmt.Printf("cidr=%s: {sip=%s, eip=%s}\n", item[0], item[1], item[2])
 	}
 }
+
+func TestCIDR2Range_Fix(t *testing.T) {
+	var strList = []string{
+		// "14.200.21.0/24",
+		"14.200.21.158/32",
+	}
+
+	for _, cidr := range strList {
+		sip, eip, err := CIDR2Range(cidr)
+		if err != nil {
+			t.Fatalf("CIDR2Range: %s", err)
+		}
+
+		fmt.Printf("cidr=%s: {sip=%s, eip=%s}\n", cidr, IP2String(sip), IP2String(eip))
+	}
+}