dkforest

commit e5b23d81f4dbcc2c33f6ac3072646940bbbdbf82
parent cf2e642848f5131522bcfe4eea6b66a88081c513
Author: n0tr1v <n0tr1v@protonmail.com>
Date:   Tue, 12 Dec 2023 18:49:11 -0500

use crypto rand for deck shuffle

Diffstat:
M
pkg/utils/utils.go
 | 
19
+++++++++++++++++++
M
pkg/web/handlers/poker/poker.go
 | 
4
+++-

2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/pkg/utils/utils.go b/pkg/utils/utils.go
@@ -596,6 +596,10 @@ func Shuffle[T any](s []T) {
 	rand.Shuffle(len(s), func(i, j int) { s[i], s[j] = s[j], s[i] })
 }
 
+func Shuffle1[T any](r *rand.Rand, s []T) {
+	r.Shuffle(len(s), func(i, j int) { s[i], s[j] = s[j], s[i] })
+}
+
 type Ints interface {
 	int | int64
 }
@@ -1156,3 +1160,18 @@ func Slice2Set[T any, U comparable](s []T, f func(T) U) *hashset.HashSet[U] {
 	}
 	return h
 }
+
+type CryptoRandSource struct{}
+
+func NewCryptoRandSource() CryptoRandSource {
+	return CryptoRandSource{}
+}
+
+func (_ CryptoRandSource) Int63() int64 {
+	var b [8]byte
+	_, _ = cryptoRand.Read(b[:])
+	// mask off sign bit to ensure positive number
+	return int64(binary.LittleEndian.Uint64(b[:]) & (1<<63 - 1))
+}
+
+func (_ CryptoRandSource) Seed(_ int64) {}
diff --git a/pkg/web/handlers/poker/poker.go b/pkg/web/handlers/poker/poker.go
@@ -10,6 +10,7 @@ import (
 	"github.com/chehsunliu/poker"
 	"github.com/labstack/echo"
 	"github.com/sirupsen/logrus"
+	"math/rand"
 	"net/http"
 	"sort"
 	"strconv"
@@ -424,7 +425,8 @@ func NewOngoing(g *PokerGame) *Ongoing {
 		"A♣", "2♣", "3♣", "4♣", "5♣", "6♣", "7♣", "8♣", "9♣", "10♣", "J♣", "Q♣", "K♣",
 		"A♦", "2♦", "3♦", "4♦", "5♦", "6♦", "7♦", "8♦", "9♦", "10♦", "J♦", "Q♦", "K♦",
 	}
-	utils.Shuffle(deck)
+	r := rand.New(utils.NewCryptoRandSource())
+	utils.Shuffle1(r, deck)
 
 	players := make([]*PokerPlayer, 0)
 	g.PlayersMtx.RLock()