From 4eb9077f1bbc729bef36096de65ab923b778592e Mon Sep 17 00:00:00 2001
From: Lucas Clemente <lucas@clemente.io>
Date: Tue, 9 Aug 2016 13:08:42 +0200
Subject: [PATCH] simplify crypto/rand reading

---
 crypto/curve_25519.go          | 3 +--
 crypto/source_address_token.go | 2 +-
 handshake/crypto_setup.go      | 5 ++---
 handshake/server_config.go     | 5 ++---
 4 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/crypto/curve_25519.go b/crypto/curve_25519.go
index 4813a2617..a570d6b31 100644
--- a/crypto/curve_25519.go
+++ b/crypto/curve_25519.go
@@ -3,7 +3,6 @@ package crypto
 import (
 	"crypto/rand"
 	"errors"
-	"io"
 
 	"golang.org/x/crypto/curve25519"
 )
@@ -19,7 +18,7 @@ var _ KeyExchange = &curve25519KEX{}
 // NewCurve25519KEX creates a new KeyExchange using Curve25519, see https://cr.yp.to/ecdh.html
 func NewCurve25519KEX() (KeyExchange, error) {
 	c := &curve25519KEX{}
-	if _, err := io.ReadFull(rand.Reader, c.secret[:]); err != nil {
+	if _, err := rand.Read(c.secret[:]); err != nil {
 		return nil, errors.New("Curve25519: could not create private key")
 	}
 	// See https://cr.yp.to/ecdh.html
diff --git a/crypto/source_address_token.go b/crypto/source_address_token.go
index 709361e98..6afdacd65 100644
--- a/crypto/source_address_token.go
+++ b/crypto/source_address_token.go
@@ -121,7 +121,7 @@ func deriveKey(secret []byte) ([]byte, error) {
 
 func encryptToken(aead cipher.AEAD, token *sourceAddressToken) ([]byte, error) {
 	nonce := make([]byte, stkNonceSize)
-	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+	if _, err := rand.Read(nonce); err != nil {
 		return nil, err
 	}
 	return aead.Seal(nonce, nonce, token.serialize(), nil), nil
diff --git a/handshake/crypto_setup.go b/handshake/crypto_setup.go
index 0c2de6439..efd265737 100644
--- a/handshake/crypto_setup.go
+++ b/handshake/crypto_setup.go
@@ -3,7 +3,6 @@ package handshake
 import (
 	"bytes"
 	"crypto/rand"
-	"io"
 	"net"
 	"sync"
 
@@ -238,12 +237,12 @@ func (h *CryptoSetup) handleCHLO(sni string, data []byte, cryptoData map[Tag][]b
 	}
 
 	nonce := make([]byte, 32)
-	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
+	if _, err = rand.Read(nonce); err != nil {
 		return nil, err
 	}
 
 	h.diversificationNonce = make([]byte, 32)
-	if _, err = io.ReadFull(rand.Reader, h.diversificationNonce); err != nil {
+	if _, err = rand.Read(h.diversificationNonce); err != nil {
 		return nil, err
 	}
 
diff --git a/handshake/server_config.go b/handshake/server_config.go
index 91e047ad6..dc33e9775 100644
--- a/handshake/server_config.go
+++ b/handshake/server_config.go
@@ -3,7 +3,6 @@ package handshake
 import (
 	"bytes"
 	"crypto/rand"
-	"io"
 
 	"github.com/lucas-clemente/quic-go/crypto"
 )
@@ -19,13 +18,13 @@ type ServerConfig struct {
 // NewServerConfig creates a new server config
 func NewServerConfig(kex crypto.KeyExchange, signer crypto.Signer) (*ServerConfig, error) {
 	id := make([]byte, 16)
-	_, err := io.ReadFull(rand.Reader, id)
+	_, err := rand.Read(id)
 	if err != nil {
 		return nil, err
 	}
 
 	stkSecret := make([]byte, 32)
-	if _, err = io.ReadFull(rand.Reader, stkSecret); err != nil {
+	if _, err = rand.Read(stkSecret); err != nil {
 		return nil, err
 	}
 	stkSource, err := crypto.NewStkSource(stkSecret)