From 3c7d5fcee11afa7887132c634ab2e84a4a44224a Mon Sep 17 00:00:00 2001
From: Eng Zer Jun <engzerjun@gmail.com>
Date: Sun, 23 Jul 2023 17:14:48 +0800
Subject: [PATCH] util: Compare password hashing method with
 `strings.EqualFold`

Comparing two strings to the same case with `strings.ToLower` is more
computational expensive than `strings.EqualFold`.

Sample benchmark:

package auth_test

import (
	"strings"
	"testing"
)

func BenchmarkToLower(b *testing.B) {
	for i := 0; i < b.N; i++ {
		if strings.ToLower("PBKDF2") != strings.ToLower("pbkdf2") {
			b.Fail()
		}
	}
}

func BenchmarkEqualFold(b *testing.B) {
	for i := 0; i < b.N; i++ {
		if !strings.EqualFold("PBKDF2", "pbkdf2") {
			b.Fail()
		}
	}
}

goos: linux
goarch: amd64
pkg: go.thethings.network/lorawan-stack/v3/pkg/auth
cpu: AMD Ryzen 7 PRO 4750U with Radeon Graphics
BenchmarkToLower-16      	14323047	        98.17 ns/op	       8 B/op	       1 allocs/op
BenchmarkEqualFold-16    	132120366	         8.705 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	go.thethings.network/lorawan-stack/v3/pkg/auth	3.267s

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
---
 pkg/auth/password.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg/auth/password.go b/pkg/auth/password.go
index 8c13f4cae2..1561fab7c1 100644
--- a/pkg/auth/password.go
+++ b/pkg/auth/password.go
@@ -92,7 +92,7 @@ func Validate(hashed, plain string) (bool, error) {
 	typ := parts[0]
 
 	for _, method := range hashValidators {
-		if strings.ToLower(typ) == strings.ToLower(method.Name()) {
+		if strings.EqualFold(typ, method.Name()) {
 			return method.Validate(hashed, plain)
 		}
 	}