diff --git a/common/protocol/http/sniff.go b/common/protocol/http/sniff.go
index db478da6..f15e6bd2 100644
--- a/common/protocol/http/sniff.go
+++ b/common/protocol/http/sniff.go
@@ -42,7 +42,7 @@ var (
 )
 
 func beginWithHTTPMethod(b []byte) error {
-	for _, m := range methods {
+	for _, m := range &methods {
 		if len(b) >= len(m) && strings.ToLower(string(b[:len(m)])) == m {
 			return nil
 		}
diff --git a/proxy/mtproto/auth.go b/proxy/mtproto/auth.go
index 973561ca..dd866239 100644
--- a/proxy/mtproto/auth.go
+++ b/proxy/mtproto/auth.go
@@ -36,7 +36,7 @@ func (a *Authentication) ApplySecret(b []byte) {
 
 func generateRandomBytes(random []byte) {
 	for {
-		common.Must2(rand.Read(random[:]))
+		common.Must2(rand.Read(random))
 
 		if random[0] == 0xef {
 			continue
diff --git a/transport/internet/kcp/crypt.go b/transport/internet/kcp/crypt.go
index 4bedbe31..61d2677e 100644
--- a/transport/internet/kcp/crypt.go
+++ b/transport/internet/kcp/crypt.go
@@ -36,14 +36,14 @@ func (a *SimpleAuthenticator) Seal(dst, nonce, plain, extra []byte) []byte {
 	common.Must2(fnvHash.Write(dst[4:]))
 	fnvHash.Sum(dst[:0])
 
-	len := len(dst)
-	xtra := 4 - len%4
+	dstLen := len(dst)
+	xtra := 4 - dstLen%4
 	if xtra != 4 {
 		dst = append(dst, make([]byte, xtra)...)
 	}
 	xorfwd(dst)
 	if xtra != 4 {
-		dst = dst[:len]
+		dst = dst[:dstLen]
 	}
 	return dst
 }