From a9c110b3c0fa9ff13b7f1f63c5d4b22f828032dd Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Tue, 16 Jul 2024 17:10:54 +0300
Subject: [PATCH] Use modern Go's clear()

---
 go.mod                        | 2 +-
 internal/gost34112012/hash.go | 2 +-
 mgm/mode.go                   | 8 ++------
 mgm/mul64.go                  | 4 +---
 4 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/go.mod b/go.mod
index f77e39a..2b80ff5 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,5 @@
 module go.cypherpunks.ru/gogost/v5
 
-go 1.20
+go 1.21
 
 require golang.org/x/crypto v0.16.0
diff --git a/internal/gost34112012/hash.go b/internal/gost34112012/hash.go
index 40eb2f0..ffd1bc0 100644
--- a/internal/gost34112012/hash.go
+++ b/internal/gost34112012/hash.go
@@ -264,8 +264,8 @@ func New(size int) *Hash {
 func (h *Hash) Reset() {
 	h.n = 0
 	h.buf = nil
+	clear(h.chk)
 	for i := 0; i < BlockSize; i++ {
-		h.chk[i] = 0
 		if h.size == 32 {
 			h.hsh[i] = 1
 		} else {
diff --git a/mgm/mode.go b/mgm/mode.go
index ba41973..588e9ad 100644
--- a/mgm/mode.go
+++ b/mgm/mode.go
@@ -110,9 +110,7 @@ func (mgm *MGM) validateSizes(text, additionalData []byte) {
 }
 
 func (mgm *MGM) auth(out, text, ad []byte) {
-	for i := 0; i < mgm.BlockSize; i++ {
-		mgm.sum[i] = 0
-	}
+	clear(mgm.sum)
 	adLen := len(ad) * 8
 	textLen := len(text) * 8
 	mgm.icn[0] |= 0x80
@@ -129,9 +127,7 @@ func (mgm *MGM) auth(out, text, ad []byte) {
 	}
 	if len(ad) > 0 {
 		copy(mgm.padded, ad)
-		for i := len(ad); i < mgm.BlockSize; i++ {
-			mgm.padded[i] = 0
-		}
+		clear(mgm.padded[len(ad):])
 		mgm.cipher.Encrypt(mgm.bufC, mgm.bufP)
 		subtle.XORBytes(mgm.sum, mgm.sum, mgm.mul.Mul(mgm.bufC, mgm.padded))
 		incr(mgm.bufP[:mgm.BlockSize/2])
diff --git a/mgm/mul64.go b/mgm/mul64.go
index 11265e2..201710c 100644
--- a/mgm/mul64.go
+++ b/mgm/mul64.go
@@ -57,9 +57,7 @@ func (mul *mul64) Mul(x, y []byte) []byte {
 	}
 	zBytes := mul.z.Bytes()
 	rem := len(x) - len(zBytes)
-	for i := 0; i < rem; i++ {
-		mul.buf[i] = 0
-	}
+	clear(mul.buf[:rem])
 	copy(mul.buf[rem:], zBytes)
 	return mul.buf[:]
 }
-- 
2.48.1