gooxml: add support for verifying versions and license

license.go

@@ -0,0 +1,185 @@
+// Copyright 2017 Baliance. All rights reserved.
+//
+// Use of this source code is governed by the terms of the Affero GNU General
+// Public License version 3.0 as published by the Free Software Foundation and
+// appearing in the file LICENSE included in the packaging of this file. A
+// commercial license can be purchased by contacting sales@baliance.com.
+
+package gooxml
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"io"
+	"log"
+	"strings"
+	"time"
+)
+
+// OpenSourceLicense is the AGPL open source license. It is installed by default
+// if no license has previously been installed.
+const OpenSourceLicense = `
+H4sIAAAAAAAC_xzJsU7DQAwA0J2vqDynks--y9nZ
+2RAMLQubfeegDKRR2kogxL8jkN72vuHZPgImeNli
+PZwu973F4fUaOwxwWt5Xu933v86Fqjfnlq1mKWzU
+SXzEwCKoqWc0sREtvCYlsdlV2b12CwqyntVk7orZ
+eTQRtMhMoonHaDh3DMsYVEir10JzbV3CW1FmyrM4
+wQCPn9uy2225rDABI-Ix0ZHTGXH69wYDPC0t1muc
+v7aAKf08_AYAAP__z2E3oN8A`
+
+var license *License
+
+const pubKeyHex = `305c300d06092a864886f70d0101010500034b003048024100b87eafb6c07499eb97cc9d3565ecf3168196301907c841addc665086bb3ed8eb12d9da26cafa96450146da8bd0ccf155fcacc686955ef0302fa44aa3ec89417b0203010001`
+
+var pubKey *rsa.PublicKey
+
+func init() {
+	pubKeyBytes, err := hex.DecodeString(pubKeyHex)
+	if err != nil {
+		log.Fatalf("error reading key: %s", err)
+	}
+	pkRaw, err := x509.ParsePKIXPublicKey(pubKeyBytes)
+	if err != nil {
+		log.Fatalf("error reading key: %s", err)
+	}
+	pubKey = pkRaw.(*rsa.PublicKey)
+}
+
+// LicenseType is the type of license
+//go:generate stringer -type=LicenseType
+type LicenseType byte
+
+// LicenseType constants
+const (
+	LicenseTypeInvalid LicenseType = iota
+	LicenseTypeAGPL
+	LicenseTypeCommercial
+)
+
+// License holds the gooxml license information.
+type License struct {
+	Name        string
+	Signature   string `json:",omitempty"`
+	Expiration  time.Time
+	LicenseType LicenseType
+}
+
+// Sign signs a license with a private key, setting the license's signature
+// value
+func (l *License) Sign(privKey *rsa.PrivateKey) error {
+	l.Signature = ""
+	buf := bytes.Buffer{}
+	enc := json.NewEncoder(&buf)
+	if err := enc.Encode(l); err != nil {
+		return err
+	}
+
+	hashed := sha256.Sum256(buf.Bytes())
+	signature, err := rsa.SignPKCS1v15(rand.Reader, privKey, crypto.SHA256, hashed[:])
+	if err != nil {
+		return err
+	}
+	l.Signature = hex.EncodeToString(signature)
+	return nil
+}
+
+// Verify verifies a license by checking the license content and signature
+// against a public key.
+func (l License) Verify(pubKey *rsa.PublicKey) error {
+	cp := l
+	cp.Signature = ""
+	buf := bytes.Buffer{}
+	enc := json.NewEncoder(&buf)
+	if err := enc.Encode(cp); err != nil {
+		return err
+	}
+	sig, err := hex.DecodeString(l.Signature)
+	if err != nil {
+		return err
+	}
+	hashed := sha256.Sum256(buf.Bytes())
+	err = rsa.VerifyPKCS1v15(pubKey, crypto.SHA256, hashed[:], sig)
+	return err
+}
+
+func (l License) String() string {
+	buf := bytes.Buffer{}
+	enc := json.NewEncoder(&buf)
+	enc.Encode(l)
+	return buf.String()
+}
+
+// Encoded returns a base64 encoded version of the license for use with
+// InstallLicense.
+func (l License) Encoded() string {
+	buf := bytes.Buffer{}
+	w := base64.NewEncoder(base64.RawURLEncoding, &buf)
+	gz, _ := gzip.NewWriterLevel(w, gzip.BestCompression)
+	enc := json.NewEncoder(gz)
+	enc.Encode(l)
+	gz.Close()
+
+	rsp := bytes.Buffer{}
+	const maxLen = 40
+	raw := buf.Bytes()
+	for i := 0; i < buf.Len(); i += maxLen {
+		rsp.Write(raw[i : i+maxLen])
+		rsp.WriteByte('\r')
+		rsp.WriteByte('\n')
+	}
+	return rsp.String()
+}
+
+// InstallLicense installs a license, returning an error if the license is
+// invalid or expired. Expiration checks the ReleaseDate variable in version.go.
+func InstallLicense(s string) error {
+	s = strings.Replace(s, "\r", "", -1)
+	s = strings.Replace(s, "\n", "", -1)
+
+	var r io.Reader
+	r = strings.NewReader(s)
+	r = base64.NewDecoder(base64.RawURLEncoding, r)
+	r, err := gzip.NewReader(r)
+	if err != nil {
+		return err
+	}
+
+	dec := json.NewDecoder(r)
+	l := &License{}
+	if err := dec.Decode(l); err != nil {
+		return err
+	}
+	// check signature
+	if err := l.Verify(pubKey); err != nil {
+		return errors.New("license validatin error")
+	}
+
+	if l.Expiration.Before(ReleaseDate) {
+		return errors.New("license expired")
+	}
+	license = l
+	return nil
+}
+
+// GetLicense returns the current license.  This can be used by commercial
+// customers to assist in ensuring that their license hasn't expired.
+func GetLicense() License {
+	if license == nil {
+		if err := InstallLicense(OpenSourceLicense); err != nil {
+			log.Printf("open source license error: %s", err)
+		}
+	}
+	if license != nil {
+		return *license
+	}
+	return License{}
+}

license_test.go

@@ -0,0 +1,15 @@
+// Copyright 2017 Baliance. All rights reserved.
+//
+// Use of this source code is governed by the terms of the Affero GNU General
+// Public License version 3.0 as published by the Free Software Foundation and
+// appearing in the file LICENSE included in the packaging of this file. A
+// commercial license can be purchased by contacting sales@baliance.com.
+
+package gooxml_test
+
+import "testing"
+import "baliance.com/gooxml"
+
+func TestOpenSourceLicense(t *testing.T) {
+	gooxml.GetLicense()
+}

licensetype_string.go

@@ -0,0 +1,16 @@
+// Code generated by "stringer -type=LicenseType"; DO NOT EDIT.
+
+package gooxml
+
+import "fmt"
+
+const _LicenseType_name = "LicenseTypeInvalidLicenseTypeAGPLLicenseTypeCommercial"
+
+var _LicenseType_index = [...]uint8{0, 18, 33, 54}
+
+func (i LicenseType) String() string {
+	if i >= LicenseType(len(_LicenseType_index)-1) {
+		return fmt.Sprintf("LicenseType(%d)", i)
+	}
+	return _LicenseType_name[_LicenseType_index[i]:_LicenseType_index[i+1]]
+}

update-version.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+
+cat << __EOF > version.go
+// Copyright `date +%Y` Baliance. All rights reserved.
+//
+// Use of this source code is governed by the terms of the Affero GNU General
+// Public License version 3.0 as published by the Free Software Foundation and
+// appearing in the file LICENSE included in the packaging of this file. A
+// commercial license can be purchased by contacting sales@baliance.com.
+
+package gooxml
+
+import "time"
+
+// ReleaseDate is the release date of the source code for licensing purposes.
+var ReleaseDate = time.Date(`date +%Y`,`date +%_m`,`date +%_d`,0,0,0,0,time.UTC)
+
+__EOF
+goimports -w version.go

version.go

@@ -0,0 +1,13 @@
+// Copyright 2017 Baliance. All rights reserved.
+//
+// Use of this source code is governed by the terms of the Affero GNU General
+// Public License version 3.0 as published by the Free Software Foundation and
+// appearing in the file LICENSE included in the packaging of this file. A
+// commercial license can be purchased by contacting sales@baliance.com.
+
+package gooxml
+
+import "time"
+
+// ReleaseDate is the release date of the source code for licensing purposes.
+var ReleaseDate = time.Date(2017, 9, 30, 0, 0, 0, 0, time.UTC)