pgp: Base pgp code

pgp/pgp.go

@@ -0,0 +1,230 @@
+// Mgmt
+// Copyright (C) 2013-2016+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package pgp
+
+import (
+	"bufio"
+	"bytes"
+	"crypto"
+	"encoding/base64"
+	"io/ioutil"
+	"log"
+	"os"
+	"strings"
+
+	errwrap "github.com/pkg/errors"
+	"golang.org/x/crypto/openpgp"
+	"golang.org/x/crypto/openpgp/packet"
+)
+
+// DefaultKeyringFile is the default file name for keyrings.
+const DefaultKeyringFile = "keyring.pgp"
+
+// CONFIG set default Hash.
+var CONFIG packet.Config
+
+func init() {
+	CONFIG.DefaultHash = crypto.SHA256
+}
+
+// PGP contains base entity.
+type PGP struct {
+	Entity *openpgp.Entity
+}
+
+// Import private key from defined path.
+func Import(privKeyPath string) (*PGP, error) {
+
+	privKeyFile, err := os.Open(privKeyPath)
+	if err != nil {
+		return nil, err
+	}
+	defer privKeyFile.Close()
+
+	file := packet.NewReader(bufio.NewReader(privKeyFile))
+	entity, err := openpgp.ReadEntity(file)
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "can't read entity from path")
+	}
+
+	obj := &PGP{
+		Entity: entity,
+	}
+
+	log.Printf("PGP: Imported key: %s", obj.Entity.PrivateKey.KeyIdShortString())
+	return obj, nil
+}
+
+// Generate creates new key pair. This key pair must be saved or it will be lost.
+func Generate(name, comment, email string, hash *crypto.Hash) (*PGP, error) {
+	if hash != nil {
+		CONFIG.DefaultHash = *hash
+	}
+	// generate a new public/private key pair
+	entity, err := openpgp.NewEntity(name, comment, email, &CONFIG)
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "can't generate entity")
+	}
+
+	obj := &PGP{
+		Entity: entity,
+	}
+
+	log.Printf("PGP: Created key: %s", obj.Entity.PrivateKey.KeyIdShortString())
+	return obj, nil
+}
+
+// SaveKey writes the whole entity (including private key!) to a .gpg file.
+func (obj *PGP) SaveKey(path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return errwrap.Wrapf(err, "can't create file from given path")
+	}
+
+	w := bufio.NewWriter(f)
+	if err != nil {
+		return errwrap.Wrapf(err, "can't create writer")
+	}
+
+	if err := obj.Entity.SerializePrivate(w, &CONFIG); err != nil {
+		return errwrap.Wrapf(err, "can't serialize private key")
+	}
+
+	for _, ident := range obj.Entity.Identities {
+		for _, sig := range ident.Signatures {
+			if err := sig.Serialize(w); err != nil {
+				return errwrap.Wrapf(err, "can't serialize signature")
+			}
+		}
+	}
+
+	if err := w.Flush(); err != nil {
+		return errwrap.Wrapf(err, "enable to flush writer")
+	}
+
+	return nil
+}
+
+// WriteFile from given buffer in specified path.
+func (obj *PGP) WriteFile(path string, buff *bytes.Buffer) error {
+	w, err := createWriter(path)
+	if err != nil {
+		return errwrap.Wrapf(err, "can't create writer")
+	}
+	buff.WriteTo(w)
+
+	if err := w.Flush(); err != nil {
+		return errwrap.Wrapf(err, "can't flush buffered data")
+	}
+	return nil
+}
+
+// CreateWriter remove duplicate function.
+func createWriter(path string) (*bufio.Writer, error) {
+	f, err := os.Create(path)
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "can't create file from given path")
+	}
+	return bufio.NewWriter(f), nil
+}
+
+// Encrypt message for specified entity.
+func (obj *PGP) Encrypt(to *openpgp.Entity, msg string) (string, error) {
+	buf, err := obj.EncryptMsg(to, msg)
+	if err != nil {
+		return "", errwrap.Wrapf(err, "can't encrypt message")
+	}
+
+	// encode to base64
+	bytes, err := ioutil.ReadAll(buf)
+	if err != nil {
+		return "", errwrap.Wrapf(err, "can't read unverified body")
+	}
+	return base64.StdEncoding.EncodeToString(bytes), nil
+}
+
+// EncryptMsg encrypts the message.
+func (obj *PGP) EncryptMsg(to *openpgp.Entity, msg string) (*bytes.Buffer, error) {
+	ents := []*openpgp.Entity{to}
+
+	buf := new(bytes.Buffer)
+	w, err := openpgp.Encrypt(buf, ents, obj.Entity, nil, nil)
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "can't encrypt message")
+	}
+
+	_, err = w.Write([]byte(msg))
+	if err != nil {
+		return nil, errwrap.Wrapf(err, "can't write to buffer")
+	}
+
+	if err = w.Close(); err != nil {
+		return nil, errwrap.Wrapf(err, "can't close writer")
+	}
+	return buf, nil
+}
+
+// Decrypt an encrypted msg.
+func (obj *PGP) Decrypt(encString string) (string, error) {
+	entityList := openpgp.EntityList{obj.Entity}
+
+	// decode the base64 string
+	dec, err := base64.StdEncoding.DecodeString(encString)
+	if err != nil {
+		return "", errwrap.Wrapf(err, "fail at decoding encrypted string")
+	}
+
+	// decrypt it with the contents of the private key
+	md, err := openpgp.ReadMessage(bytes.NewBuffer(dec), entityList, nil, nil)
+	if err != nil {
+		return "", errwrap.Wrapf(err, "can't read message")
+	}
+
+	bytes, err := ioutil.ReadAll(md.UnverifiedBody)
+	if err != nil {
+		return "", errwrap.Wrapf(err, "can't read unverified body")
+	}
+	return string(bytes), nil
+}
+
+// GetIdentities return the first identities from current object.
+func (obj *PGP) GetIdentities() (string, error) {
+	identities := []*openpgp.Identity{}
+
+	for _, v := range obj.Entity.Identities {
+		identities = append(identities, v)
+	}
+	return identities[0].Name, nil
+}
+
+// ParseIdentity parses an identity into name, comment and email components.
+func ParseIdentity(identity string) (name, comment, email string, err error) {
+	// get name
+	n := strings.Split(identity, " <")
+	if len(n) != 2 {
+		return "", "", "", errwrap.Wrap(err, "user string mal formated")
+	}
+
+	// get email and comment
+	ec := strings.Split(n[1], "> ")
+	if len(ec) != 2 {
+		return "", "", "", errwrap.Wrap(err, "user string mal formated")
+	}
+
+	return n[0], ec[1], ec[0], nil
+}