From c63a88072b581eb6f77087daced3bd1ed62d3ba3 Mon Sep 17 00:00:00 2001
From: Adam Langley <agl@golang.org>
Date: Sat, 5 Feb 2011 12:06:42 -0500
Subject: [PATCH] crypto/openpgp/packet: two more packet types.

R=bradfitzgo, r
CC=golang-dev
https://golang.org/cl/4124054
---
 src/pkg/crypto/openpgp/packet/compressed.go   |  39 +++++
 .../crypto/openpgp/packet/compressed_test.go  |  41 +++++
 src/pkg/crypto/openpgp/packet/private_key.go  | 164 ++++++++++++++++++
 .../crypto/openpgp/packet/private_key_test.go |  37 ++++
 4 files changed, 281 insertions(+)
 create mode 100644 src/pkg/crypto/openpgp/packet/compressed.go
 create mode 100644 src/pkg/crypto/openpgp/packet/compressed_test.go
 create mode 100644 src/pkg/crypto/openpgp/packet/private_key.go
 create mode 100644 src/pkg/crypto/openpgp/packet/private_key_test.go

diff --git a/src/pkg/crypto/openpgp/packet/compressed.go b/src/pkg/crypto/openpgp/packet/compressed.go
new file mode 100644
index 0000000000..1c15c24c4b
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/compressed.go
@@ -0,0 +1,39 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"compress/flate"
+	"compress/zlib"
+	"crypto/openpgp/error"
+	"io"
+	"os"
+	"strconv"
+)
+
+// Compressed represents a compressed OpenPGP packet. The decompressed contents
+// will contain more OpenPGP packets. See RFC 4880, section 5.6.
+type Compressed struct {
+	Body io.Reader
+}
+
+func (c *Compressed) parse(r io.Reader) os.Error {
+	var buf [1]byte
+	_, err := readFull(r, buf[:])
+	if err != nil {
+		return err
+	}
+
+	switch buf[0] {
+	case 1:
+		c.Body = flate.NewReader(r)
+	case 2:
+		c.Body, err = zlib.NewReader(r)
+	default:
+		err = error.UnsupportedError("unknown compression algorithm: " + strconv.Itoa(int(buf[0])))
+	}
+
+	return err
+}
diff --git a/src/pkg/crypto/openpgp/packet/compressed_test.go b/src/pkg/crypto/openpgp/packet/compressed_test.go
new file mode 100644
index 0000000000..24fe501edb
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/compressed_test.go
@@ -0,0 +1,41 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"encoding/hex"
+	"os"
+	"io/ioutil"
+	"testing"
+)
+
+func TestCompressed(t *testing.T) {
+	packet, err := Read(readerFromHex(compressedHex))
+	if err != nil {
+		t.Errorf("failed to read Compressed: %s", err)
+		return
+	}
+
+	c, ok := packet.(*Compressed)
+	if !ok {
+		t.Error("didn't find Compressed packet")
+		return
+	}
+
+	contents, err := ioutil.ReadAll(c.Body)
+	if err != nil && err != os.EOF {
+		t.Error(err)
+		return
+	}
+
+	expected, _ := hex.DecodeString(compressedExpectedHex)
+	if !bytes.Equal(expected, contents) {
+		t.Errorf("got:%x want:%x", contents, expected)
+	}
+}
+
+const compressedHex = "a3013b2d90c4e02b72e25f727e5e496a5e49b11e1700"
+const compressedExpectedHex = "cb1062004d14c8fe636f6e74656e74732e0a"
diff --git a/src/pkg/crypto/openpgp/packet/private_key.go b/src/pkg/crypto/openpgp/packet/private_key.go
new file mode 100644
index 0000000000..b22891755e
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/private_key.go
@@ -0,0 +1,164 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"big"
+	"bytes"
+	"crypto/cipher"
+	"crypto/openpgp/error"
+	"crypto/openpgp/s2k"
+	"crypto/rsa"
+	"crypto/sha1"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+)
+
+// PrivateKey represents a possibly encrypted private key. See RFC 4880,
+// section 5.5.3.
+type PrivateKey struct {
+	PublicKey
+	Encrypted     bool // if true then the private key is unavailable until Decrypt has been called.
+	encryptedData []byte
+	cipher        CipherFunction
+	s2k           func(out, in []byte)
+	PrivateKey    interface{} // An *rsa.PrivateKey.
+	sha1Checksum  bool
+	iv            []byte
+}
+
+func (pk *PrivateKey) parse(r io.Reader) (err os.Error) {
+	err = (&pk.PublicKey).parse(r)
+	if err != nil {
+		return
+	}
+	var buf [1]byte
+	_, err = readFull(r, buf[:])
+	if err != nil {
+		return
+	}
+
+	s2kType := buf[0]
+
+	switch s2kType {
+	case 0:
+		pk.s2k = nil
+		pk.Encrypted = false
+	case 254, 255:
+		_, err = readFull(r, buf[:])
+		if err != nil {
+			return
+		}
+		pk.cipher = CipherFunction(buf[0])
+		pk.Encrypted = true
+		pk.s2k, err = s2k.Parse(r)
+		if err != nil {
+			return
+		}
+		if s2kType == 254 {
+			pk.sha1Checksum = true
+		}
+	default:
+		return error.UnsupportedError("deprecated s2k function in private key")
+	}
+
+	if pk.Encrypted {
+		blockSize := pk.cipher.blockSize()
+		if blockSize == 0 {
+			return error.UnsupportedError("unsupported cipher in private key: " + strconv.Itoa(int(pk.cipher)))
+		}
+		pk.iv = make([]byte, blockSize)
+		_, err = readFull(r, pk.iv)
+		if err != nil {
+			return
+		}
+	}
+
+	pk.encryptedData, err = ioutil.ReadAll(r)
+	if err != nil {
+		return
+	}
+
+	if !pk.Encrypted {
+		return pk.parsePrivateKey(pk.encryptedData)
+	}
+
+	return
+}
+
+// Decrypt decrypts an encrypted private key using a passphrase.
+func (pk *PrivateKey) Decrypt(passphrase []byte) os.Error {
+	if !pk.Encrypted {
+		return nil
+	}
+
+	key := make([]byte, pk.cipher.keySize())
+	pk.s2k(key, passphrase)
+	block := pk.cipher.new(key)
+	cfb := cipher.NewCFBDecrypter(block, pk.iv)
+
+	data := pk.encryptedData
+	cfb.XORKeyStream(data, data)
+
+	if pk.sha1Checksum {
+		if len(data) < sha1.Size {
+			return error.StructuralError("truncated private key data")
+		}
+		h := sha1.New()
+		h.Write(data[:len(data)-sha1.Size])
+		sum := h.Sum()
+		if !bytes.Equal(sum, data[len(data)-sha1.Size:]) {
+			return error.StructuralError("private key checksum failure")
+		}
+		data = data[:len(data)-sha1.Size]
+	} else {
+		if len(data) < 2 {
+			return error.StructuralError("truncated private key data")
+		}
+		var sum uint16
+		for i := 0; i < len(data)-2; i++ {
+			sum += uint16(data[i])
+		}
+		if data[len(data)-2] != uint8(sum>>8) ||
+			data[len(data)-1] != uint8(sum) {
+			return error.StructuralError("private key checksum failure")
+		}
+		data = data[:len(data)-2]
+	}
+
+	return pk.parsePrivateKey(data)
+}
+
+func (pk *PrivateKey) parsePrivateKey(data []byte) (err os.Error) {
+	// TODO(agl): support DSA and ECDSA private keys.
+	rsaPub := pk.PublicKey.PublicKey.(*rsa.PublicKey)
+	rsaPriv := new(rsa.PrivateKey)
+	rsaPriv.PublicKey = *rsaPub
+
+	buf := bytes.NewBuffer(data)
+	d, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+	p, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+	q, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+
+	rsaPriv.D = new(big.Int).SetBytes(d)
+	rsaPriv.P = new(big.Int).SetBytes(p)
+	rsaPriv.Q = new(big.Int).SetBytes(q)
+	pk.PrivateKey = rsaPriv
+	pk.Encrypted = false
+	pk.encryptedData = nil
+
+	return nil
+}
diff --git a/src/pkg/crypto/openpgp/packet/private_key_test.go b/src/pkg/crypto/openpgp/packet/private_key_test.go
new file mode 100644
index 0000000000..e941cc735c
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/private_key_test.go
@@ -0,0 +1,37 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"testing"
+)
+
+func TestPrivateKeyRead(t *testing.T) {
+	packet, err := Read(readerFromHex(privKeyHex))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	privKey := packet.(*PrivateKey)
+
+	if !privKey.Encrypted {
+		t.Error("private key isn't encrypted")
+		return
+	}
+
+	err = privKey.Decrypt([]byte("testing"))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if privKey.CreationTime != 0x4cc349a8 || privKey.Encrypted {
+		t.Errorf("failed to parse, got: %#v", privKey)
+	}
+}
+
+// Generated with `gpg --export-secret-keys "Test Key 2"`
+const privKeyHex = "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"