crypto/...: more fixes for bug 2841

1) Remove the Reset() member in crypto/aes and crypto/des (and
   document the change).
2) Turn several empty error structures into vars. Any remaining error
   structures are either non-empty, or will probably become so in the
   future.
3) Implement SetWriteDeadline for TLS sockets. At the moment, the TLS
   status cannot be reused after a Write error, which is probably fine
   for most uses.
4) Make crypto/aes and crypto/des return a cipher.Block.

R=rsc, r
CC=golang-dev
http://codereview.appspot.com/5625045

5 files changed, 17 insertions, 13 deletions

diff --git a/src/pkg/crypto/cipher/cbc_aes_test.go b/src/pkg/crypto/cipher/cbc_aes_test.go
index 944ca1ba8..cee3a784b 100644
--- a/src/pkg/crypto/cipher/cbc_aes_test.go
+++ b/src/pkg/crypto/cipher/cbc_aes_test.go
@@ -8,11 +8,12 @@
 // Special Publication 800-38A, ``Recommendation for Block Cipher
 // Modes of Operation,'' 2001 Edition, pp. 24-29.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"testing"
 )
 
@@ -72,14 +73,14 @@ func TestCBC_AES(t *testing.T) {
 			continue
 		}
 
-		encrypter := NewCBCEncrypter(c, tt.iv)
+		encrypter := cipher.NewCBCEncrypter(c, tt.iv)
 		d := make([]byte, len(tt.in))
 		encrypter.CryptBlocks(d, tt.in)
 		if !bytes.Equal(tt.out, d) {
 			t.Errorf("%s: CBCEncrypter\nhave %x\nwant %x", test, d, tt.out)
 		}
 
-		decrypter := NewCBCDecrypter(c, tt.iv)
+		decrypter := cipher.NewCBCDecrypter(c, tt.iv)
 		p := make([]byte, len(d))
 		decrypter.CryptBlocks(p, d)
 		if !bytes.Equal(tt.in, p) {
diff --git a/src/pkg/crypto/cipher/cfb_test.go b/src/pkg/crypto/cipher/cfb_test.go
index 9547bfceb..f704b337e 100644
--- a/src/pkg/crypto/cipher/cfb_test.go
+++ b/src/pkg/crypto/cipher/cfb_test.go
@@ -2,11 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"crypto/rand"
 	"testing"
 )
@@ -21,11 +22,11 @@ func TestCFB(t *testing.T) {
 	plaintext := []byte("this is the plaintext")
 	iv := make([]byte, block.BlockSize())
 	rand.Reader.Read(iv)
-	cfb := NewCFBEncrypter(block, iv)
+	cfb := cipher.NewCFBEncrypter(block, iv)
 	ciphertext := make([]byte, len(plaintext))
 	cfb.XORKeyStream(ciphertext, plaintext)
 
-	cfbdec := NewCFBDecrypter(block, iv)
+	cfbdec := cipher.NewCFBDecrypter(block, iv)
 	plaintextCopy := make([]byte, len(plaintext))
 	cfbdec.XORKeyStream(plaintextCopy, ciphertext)
 
diff --git a/src/pkg/crypto/cipher/common_test.go b/src/pkg/crypto/cipher/common_test.go
index fb755757c..c75c919d1 100644
--- a/src/pkg/crypto/cipher/common_test.go
+++ b/src/pkg/crypto/cipher/common_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package cipher
+package cipher_test
 
 // Common values for tests.
 
diff --git a/src/pkg/crypto/cipher/ctr_aes_test.go b/src/pkg/crypto/cipher/ctr_aes_test.go
index 8dca9968c..d019ae0d0 100644
--- a/src/pkg/crypto/cipher/ctr_aes_test.go
+++ b/src/pkg/crypto/cipher/ctr_aes_test.go
@@ -8,11 +8,12 @@
 // Special Publication 800-38A, ``Recommendation for Block Cipher
 // Modes of Operation,'' 2001 Edition, pp. 55-58.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"testing"
 )
 
@@ -76,7 +77,7 @@ func TestCTR_AES(t *testing.T) {
 
 		for j := 0; j <= 5; j += 5 {
 			in := tt.in[0 : len(tt.in)-j]
-			ctr := NewCTR(c, tt.iv)
+			ctr := cipher.NewCTR(c, tt.iv)
 			encrypted := make([]byte, len(in))
 			ctr.XORKeyStream(encrypted, in)
 			if out := tt.out[0:len(in)]; !bytes.Equal(out, encrypted) {
@@ -86,7 +87,7 @@ func TestCTR_AES(t *testing.T) {
 
 		for j := 0; j <= 7; j += 7 {
 			in := tt.out[0 : len(tt.out)-j]
-			ctr := NewCTR(c, tt.iv)
+			ctr := cipher.NewCTR(c, tt.iv)
 			plain := make([]byte, len(in))
 			ctr.XORKeyStream(plain, in)
 			if out := tt.in[0:len(in)]; !bytes.Equal(out, plain) {
diff --git a/src/pkg/crypto/cipher/ofb_test.go b/src/pkg/crypto/cipher/ofb_test.go
index 9b4495c88..8d3c5d3a3 100644
--- a/src/pkg/crypto/cipher/ofb_test.go
+++ b/src/pkg/crypto/cipher/ofb_test.go
@@ -8,11 +8,12 @@
 // Special Publication 800-38A, ``Recommendation for Block Cipher
 // Modes of Operation,'' 2001 Edition, pp. 52-55.
 
-package cipher
+package cipher_test
 
 import (
 	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 	"testing"
 )
 
@@ -76,7 +77,7 @@ func TestOFB(t *testing.T) {
 
 		for j := 0; j <= 5; j += 5 {
 			plaintext := tt.in[0 : len(tt.in)-j]
-			ofb := NewOFB(c, tt.iv)
+			ofb := cipher.NewOFB(c, tt.iv)
 			ciphertext := make([]byte, len(plaintext))
 			ofb.XORKeyStream(ciphertext, plaintext)
 			if !bytes.Equal(ciphertext, tt.out[:len(plaintext)]) {
@@ -86,7 +87,7 @@ func TestOFB(t *testing.T) {
 
 		for j := 0; j <= 5; j += 5 {
 			ciphertext := tt.out[0 : len(tt.in)-j]
-			ofb := NewOFB(c, tt.iv)
+			ofb := cipher.NewOFB(c, tt.iv)
 			plaintext := make([]byte, len(ciphertext))
 			ofb.XORKeyStream(plaintext, ciphertext)
 			if !bytes.Equal(plaintext, tt.in[:len(ciphertext)]) {