crypto: use bytes.Clone

Change-Id: I92e110023739c6f8f7815c7e47ad7639c4e8812d
Reviewed-on: https://go-review.googlesource.com/c/go/+/435279
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: xie cui <523516579@qq.com>

3 files changed, 4 insertions, 10 deletions

diff --git a/src/crypto/cipher/cbc.go b/src/crypto/cipher/cbc.go
index fe774c116e..51a142071f 100644
--- a/src/crypto/cipher/cbc.go
+++ b/src/crypto/cipher/cbc.go
@@ -12,6 +12,7 @@
 package cipher
 
 import (
+	"bytes"
 	"crypto/internal/alias"
 	"crypto/subtle"
 )
@@ -27,7 +28,7 @@ func newCBC(b Block, iv []byte) *cbc {
 	return &cbc{
 		b:         b,
 		blockSize: b.BlockSize(),
-		iv:        dup(iv),
+		iv:        bytes.Clone(iv),
 		tmp:       make([]byte, b.BlockSize()),
 	}
 }
diff --git a/src/crypto/cipher/cipher.go b/src/crypto/cipher/cipher.go
index 7e1a4de9a3..df6f596b4d 100644
--- a/src/crypto/cipher/cipher.go
+++ b/src/crypto/cipher/cipher.go
@@ -59,11 +59,3 @@ type BlockMode interface {
 	// maintains state and does not reset at each CryptBlocks call.
 	CryptBlocks(dst, src []byte)
 }
-
-// Utility routines
-
-func dup(p []byte) []byte {
-	q := make([]byte, len(p))
-	copy(q, p)
-	return q
-}
diff --git a/src/crypto/cipher/ctr.go b/src/crypto/cipher/ctr.go
index 2b434ef832..3ac0ff74d0 100644
--- a/src/crypto/cipher/ctr.go
+++ b/src/crypto/cipher/ctr.go
@@ -13,6 +13,7 @@
 package cipher
 
 import (
+	"bytes"
 	"crypto/internal/alias"
 	"crypto/subtle"
 )
@@ -48,7 +49,7 @@ func NewCTR(block Block, iv []byte) Stream {
 	}
 	return &ctr{
 		b:       block,
-		ctr:     dup(iv),
+		ctr:     bytes.Clone(iv),
 		out:     make([]byte, 0, bufSize),
 		outUsed: 0,
 	}