local-server/vendor/github.com/cloudflare/cfssl/csr/csr.go
2019-01-22 11:44:11 +13:00

439 lines
11 KiB
Go

// Package csr implements certificate requests for CFSSL.
package csr
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/pem"
"errors"
"net"
"net/mail"
"net/url"
"strings"
cferr "github.com/cloudflare/cfssl/errors"
"github.com/cloudflare/cfssl/helpers"
"github.com/cloudflare/cfssl/log"
)
const (
curveP256 = 256
curveP384 = 384
curveP521 = 521
)
// A Name contains the SubjectInfo fields.
type Name struct {
C string // Country
ST string // State
L string // Locality
O string // OrganisationName
OU string // OrganisationalUnitName
SerialNumber string
}
// A KeyRequest is a generic request for a new key.
type KeyRequest interface {
Algo() string
Size() int
Generate() (crypto.PrivateKey, error)
SigAlgo() x509.SignatureAlgorithm
}
// A BasicKeyRequest contains the algorithm and key size for a new private key.
type BasicKeyRequest struct {
A string `json:"algo" yaml:"algo"`
S int `json:"size" yaml:"size"`
}
// NewBasicKeyRequest returns a default BasicKeyRequest.
func NewBasicKeyRequest() *BasicKeyRequest {
return &BasicKeyRequest{"ecdsa", curveP256}
}
// Algo returns the requested key algorithm represented as a string.
func (kr *BasicKeyRequest) Algo() string {
return kr.A
}
// Size returns the requested key size.
func (kr *BasicKeyRequest) Size() int {
return kr.S
}
// Generate generates a key as specified in the request. Currently,
// only ECDSA and RSA are supported.
func (kr *BasicKeyRequest) Generate() (crypto.PrivateKey, error) {
log.Debugf("generate key from request: algo=%s, size=%d", kr.Algo(), kr.Size())
switch kr.Algo() {
case "rsa":
if kr.Size() < 2048 {
return nil, errors.New("RSA key is too weak")
}
if kr.Size() > 8192 {
return nil, errors.New("RSA key size too large")
}
return rsa.GenerateKey(rand.Reader, kr.Size())
case "ecdsa":
var curve elliptic.Curve
switch kr.Size() {
case curveP256:
curve = elliptic.P256()
case curveP384:
curve = elliptic.P384()
case curveP521:
curve = elliptic.P521()
default:
return nil, errors.New("invalid curve")
}
return ecdsa.GenerateKey(curve, rand.Reader)
default:
return nil, errors.New("invalid algorithm")
}
}
// SigAlgo returns an appropriate X.509 signature algorithm given the
// key request's type and size.
func (kr *BasicKeyRequest) SigAlgo() x509.SignatureAlgorithm {
switch kr.Algo() {
case "rsa":
switch {
case kr.Size() >= 4096:
return x509.SHA512WithRSA
case kr.Size() >= 3072:
return x509.SHA384WithRSA
case kr.Size() >= 2048:
return x509.SHA256WithRSA
default:
return x509.SHA1WithRSA
}
case "ecdsa":
switch kr.Size() {
case curveP521:
return x509.ECDSAWithSHA512
case curveP384:
return x509.ECDSAWithSHA384
case curveP256:
return x509.ECDSAWithSHA256
default:
return x509.ECDSAWithSHA1
}
default:
return x509.UnknownSignatureAlgorithm
}
}
// CAConfig is a section used in the requests initialising a new CA.
type CAConfig struct {
PathLength int `json:"pathlen" yaml:"pathlen"`
PathLenZero bool `json:"pathlenzero" yaml:"pathlenzero"`
Expiry string `json:"expiry" yaml:"expiry"`
Backdate string `json:"backdate" yaml:"backdate"`
}
// A CertificateRequest encapsulates the API interface to the
// certificate request functionality.
type CertificateRequest struct {
CN string
Names []Name `json:"names" yaml:"names"`
Hosts []string `json:"hosts" yaml:"hosts"`
KeyRequest KeyRequest `json:"key,omitempty" yaml:"key,omitempty"`
CA *CAConfig `json:"ca,omitempty" yaml:"ca,omitempty"`
SerialNumber string `json:"serialnumber,omitempty" yaml:"serialnumber,omitempty"`
}
// New returns a new, empty CertificateRequest with a
// BasicKeyRequest.
func New() *CertificateRequest {
return &CertificateRequest{
KeyRequest: NewBasicKeyRequest(),
}
}
// appendIf appends to a if s is not an empty string.
func appendIf(s string, a *[]string) {
if s != "" {
*a = append(*a, s)
}
}
// Name returns the PKIX name for the request.
func (cr *CertificateRequest) Name() pkix.Name {
var name pkix.Name
name.CommonName = cr.CN
for _, n := range cr.Names {
appendIf(n.C, &name.Country)
appendIf(n.ST, &name.Province)
appendIf(n.L, &name.Locality)
appendIf(n.O, &name.Organization)
appendIf(n.OU, &name.OrganizationalUnit)
}
name.SerialNumber = cr.SerialNumber
return name
}
// BasicConstraints CSR information RFC 5280, 4.2.1.9
type BasicConstraints struct {
IsCA bool `asn1:"optional"`
MaxPathLen int `asn1:"optional,default:-1"`
}
// ParseRequest takes a certificate request and generates a key and
// CSR from it. It does no validation -- caveat emptor. It will,
// however, fail if the key request is not valid (i.e., an unsupported
// curve or RSA key size). The lack of validation was specifically
// chosen to allow the end user to define a policy and validate the
// request appropriately before calling this function.
func ParseRequest(req *CertificateRequest) (csr, key []byte, err error) {
log.Info("received CSR")
if req.KeyRequest == nil {
req.KeyRequest = NewBasicKeyRequest()
}
log.Infof("generating key: %s-%d", req.KeyRequest.Algo(), req.KeyRequest.Size())
priv, err := req.KeyRequest.Generate()
if err != nil {
err = cferr.Wrap(cferr.PrivateKeyError, cferr.GenerationFailed, err)
return
}
switch priv := priv.(type) {
case *rsa.PrivateKey:
key = x509.MarshalPKCS1PrivateKey(priv)
block := pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: key,
}
key = pem.EncodeToMemory(&block)
case *ecdsa.PrivateKey:
key, err = x509.MarshalECPrivateKey(priv)
if err != nil {
err = cferr.Wrap(cferr.PrivateKeyError, cferr.Unknown, err)
return
}
block := pem.Block{
Type: "EC PRIVATE KEY",
Bytes: key,
}
key = pem.EncodeToMemory(&block)
default:
panic("Generate should have failed to produce a valid key.")
}
csr, err = Generate(priv.(crypto.Signer), req)
if err != nil {
log.Errorf("failed to generate a CSR: %v", err)
err = cferr.Wrap(cferr.CSRError, cferr.BadRequest, err)
}
return
}
// ExtractCertificateRequest extracts a CertificateRequest from
// x509.Certificate. It is aimed to used for generating a new certificate
// from an existing certificate. For a root certificate, the CA expiry
// length is calculated as the duration between cert.NotAfter and cert.NotBefore.
func ExtractCertificateRequest(cert *x509.Certificate) *CertificateRequest {
req := New()
req.CN = cert.Subject.CommonName
req.Names = getNames(cert.Subject)
req.Hosts = getHosts(cert)
req.SerialNumber = cert.Subject.SerialNumber
if cert.IsCA {
req.CA = new(CAConfig)
// CA expiry length is calculated based on the input cert
// issue date and expiry date.
req.CA.Expiry = cert.NotAfter.Sub(cert.NotBefore).String()
req.CA.PathLength = cert.MaxPathLen
req.CA.PathLenZero = cert.MaxPathLenZero
}
return req
}
func getHosts(cert *x509.Certificate) []string {
var hosts []string
for _, ip := range cert.IPAddresses {
hosts = append(hosts, ip.String())
}
for _, dns := range cert.DNSNames {
hosts = append(hosts, dns)
}
for _, email := range cert.EmailAddresses {
hosts = append(hosts, email)
}
for _, uri := range cert.URIs {
hosts = append(hosts, uri.String())
}
return hosts
}
// getNames returns an array of Names from the certificate
// It onnly cares about Country, Organization, OrganizationalUnit, Locality, Province
func getNames(sub pkix.Name) []Name {
// anonymous func for finding the max of a list of interger
max := func(v1 int, vn ...int) (max int) {
max = v1
for i := 0; i < len(vn); i++ {
if vn[i] > max {
max = vn[i]
}
}
return max
}
nc := len(sub.Country)
norg := len(sub.Organization)
nou := len(sub.OrganizationalUnit)
nl := len(sub.Locality)
np := len(sub.Province)
n := max(nc, norg, nou, nl, np)
names := make([]Name, n)
for i := range names {
if i < nc {
names[i].C = sub.Country[i]
}
if i < norg {
names[i].O = sub.Organization[i]
}
if i < nou {
names[i].OU = sub.OrganizationalUnit[i]
}
if i < nl {
names[i].L = sub.Locality[i]
}
if i < np {
names[i].ST = sub.Province[i]
}
}
return names
}
// A Generator is responsible for validating certificate requests.
type Generator struct {
Validator func(*CertificateRequest) error
}
// ProcessRequest validates and processes the incoming request. It is
// a wrapper around a validator and the ParseRequest function.
func (g *Generator) ProcessRequest(req *CertificateRequest) (csr, key []byte, err error) {
log.Info("generate received request")
err = g.Validator(req)
if err != nil {
log.Warningf("invalid request: %v", err)
return nil, nil, err
}
csr, key, err = ParseRequest(req)
if err != nil {
return nil, nil, err
}
return
}
// IsNameEmpty returns true if the name has no identifying information in it.
func IsNameEmpty(n Name) bool {
empty := func(s string) bool { return strings.TrimSpace(s) == "" }
if empty(n.C) && empty(n.ST) && empty(n.L) && empty(n.O) && empty(n.OU) {
return true
}
return false
}
// Regenerate uses the provided CSR as a template for signing a new
// CSR using priv.
func Regenerate(priv crypto.Signer, csr []byte) ([]byte, error) {
req, extra, err := helpers.ParseCSR(csr)
if err != nil {
return nil, err
} else if len(extra) > 0 {
return nil, errors.New("csr: trailing data in certificate request")
}
return x509.CreateCertificateRequest(rand.Reader, req, priv)
}
// Generate creates a new CSR from a CertificateRequest structure and
// an existing key. The KeyRequest field is ignored.
func Generate(priv crypto.Signer, req *CertificateRequest) (csr []byte, err error) {
sigAlgo := helpers.SignerAlgo(priv)
if sigAlgo == x509.UnknownSignatureAlgorithm {
return nil, cferr.New(cferr.PrivateKeyError, cferr.Unavailable)
}
var tpl = x509.CertificateRequest{
Subject: req.Name(),
SignatureAlgorithm: sigAlgo,
}
for i := range req.Hosts {
if ip := net.ParseIP(req.Hosts[i]); ip != nil {
tpl.IPAddresses = append(tpl.IPAddresses, ip)
} else if email, err := mail.ParseAddress(req.Hosts[i]); err == nil && email != nil {
tpl.EmailAddresses = append(tpl.EmailAddresses, email.Address)
} else if uri, err := url.ParseRequestURI(req.Hosts[i]); err == nil && uri != nil {
tpl.URIs = append(tpl.URIs, uri)
} else {
tpl.DNSNames = append(tpl.DNSNames, req.Hosts[i])
}
}
if req.CA != nil {
err = appendCAInfoToCSR(req.CA, &tpl)
if err != nil {
err = cferr.Wrap(cferr.CSRError, cferr.GenerationFailed, err)
return
}
}
csr, err = x509.CreateCertificateRequest(rand.Reader, &tpl, priv)
if err != nil {
log.Errorf("failed to generate a CSR: %v", err)
err = cferr.Wrap(cferr.CSRError, cferr.BadRequest, err)
return
}
block := pem.Block{
Type: "CERTIFICATE REQUEST",
Bytes: csr,
}
log.Info("encoded CSR")
csr = pem.EncodeToMemory(&block)
return
}
// appendCAInfoToCSR appends CAConfig BasicConstraint extension to a CSR
func appendCAInfoToCSR(reqConf *CAConfig, csr *x509.CertificateRequest) error {
pathlen := reqConf.PathLength
if pathlen == 0 && !reqConf.PathLenZero {
pathlen = -1
}
val, err := asn1.Marshal(BasicConstraints{true, pathlen})
if err != nil {
return err
}
csr.ExtraExtensions = []pkix.Extension{
{
Id: asn1.ObjectIdentifier{2, 5, 29, 19},
Value: val,
Critical: true,
},
}
return nil
}