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

570 lines
18 KiB
Go

// Package local implements certificate signature functionality for CFSSL.
package local
import (
"bytes"
"crypto"
"crypto/rand"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/hex"
"encoding/pem"
"errors"
"io"
"math/big"
"net"
"net/http"
"net/mail"
"net/url"
"os"
"github.com/cloudflare/cfssl/certdb"
"github.com/cloudflare/cfssl/config"
cferr "github.com/cloudflare/cfssl/errors"
"github.com/cloudflare/cfssl/helpers"
"github.com/cloudflare/cfssl/info"
"github.com/cloudflare/cfssl/log"
"github.com/cloudflare/cfssl/signer"
"github.com/google/certificate-transparency-go"
"github.com/google/certificate-transparency-go/client"
"github.com/google/certificate-transparency-go/jsonclient"
"golang.org/x/net/context"
)
// Signer contains a signer that uses the standard library to
// support both ECDSA and RSA CA keys.
type Signer struct {
ca *x509.Certificate
priv crypto.Signer
policy *config.Signing
sigAlgo x509.SignatureAlgorithm
dbAccessor certdb.Accessor
}
// NewSigner creates a new Signer directly from a
// private key and certificate, with optional policy.
func NewSigner(priv crypto.Signer, cert *x509.Certificate, sigAlgo x509.SignatureAlgorithm, policy *config.Signing) (*Signer, error) {
if policy == nil {
policy = &config.Signing{
Profiles: map[string]*config.SigningProfile{},
Default: config.DefaultConfig()}
}
if !policy.Valid() {
return nil, cferr.New(cferr.PolicyError, cferr.InvalidPolicy)
}
return &Signer{
ca: cert,
priv: priv,
sigAlgo: sigAlgo,
policy: policy,
}, nil
}
// NewSignerFromFile generates a new local signer from a caFile
// and a caKey file, both PEM encoded.
func NewSignerFromFile(caFile, caKeyFile string, policy *config.Signing) (*Signer, error) {
log.Debug("Loading CA: ", caFile)
ca, err := helpers.ReadBytes(caFile)
if err != nil {
return nil, err
}
log.Debug("Loading CA key: ", caKeyFile)
cakey, err := helpers.ReadBytes(caKeyFile)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.ReadFailed, err)
}
parsedCa, err := helpers.ParseCertificatePEM(ca)
if err != nil {
return nil, err
}
strPassword := os.Getenv("CFSSL_CA_PK_PASSWORD")
password := []byte(strPassword)
if strPassword == "" {
password = nil
}
priv, err := helpers.ParsePrivateKeyPEMWithPassword(cakey, password)
if err != nil {
log.Debug("Malformed private key %v", err)
return nil, err
}
return NewSigner(priv, parsedCa, signer.DefaultSigAlgo(priv), policy)
}
func (s *Signer) sign(template *x509.Certificate) (cert []byte, err error) {
var initRoot bool
if s.ca == nil {
if !template.IsCA {
err = cferr.New(cferr.PolicyError, cferr.InvalidRequest)
return
}
template.DNSNames = nil
template.EmailAddresses = nil
template.URIs = nil
s.ca = template
initRoot = true
}
derBytes, err := x509.CreateCertificate(rand.Reader, template, s.ca, template.PublicKey, s.priv)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
}
if initRoot {
s.ca, err = x509.ParseCertificate(derBytes)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.ParseFailed, err)
}
}
cert = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
log.Infof("signed certificate with serial number %d", template.SerialNumber)
return
}
// replaceSliceIfEmpty replaces the contents of replaced with newContents if
// the slice referenced by replaced is empty
func replaceSliceIfEmpty(replaced, newContents *[]string) {
if len(*replaced) == 0 {
*replaced = *newContents
}
}
// PopulateSubjectFromCSR has functionality similar to Name, except
// it fills the fields of the resulting pkix.Name with req's if the
// subject's corresponding fields are empty
func PopulateSubjectFromCSR(s *signer.Subject, req pkix.Name) pkix.Name {
// if no subject, use req
if s == nil {
return req
}
name := s.Name()
if name.CommonName == "" {
name.CommonName = req.CommonName
}
replaceSliceIfEmpty(&name.Country, &req.Country)
replaceSliceIfEmpty(&name.Province, &req.Province)
replaceSliceIfEmpty(&name.Locality, &req.Locality)
replaceSliceIfEmpty(&name.Organization, &req.Organization)
replaceSliceIfEmpty(&name.OrganizationalUnit, &req.OrganizationalUnit)
if name.SerialNumber == "" {
name.SerialNumber = req.SerialNumber
}
return name
}
// OverrideHosts fills template's IPAddresses, EmailAddresses, DNSNames, and URIs with the
// content of hosts, if it is not nil.
func OverrideHosts(template *x509.Certificate, hosts []string) {
if hosts != nil {
template.IPAddresses = []net.IP{}
template.EmailAddresses = []string{}
template.DNSNames = []string{}
template.URIs = []*url.URL{}
}
for i := range hosts {
if ip := net.ParseIP(hosts[i]); ip != nil {
template.IPAddresses = append(template.IPAddresses, ip)
} else if email, err := mail.ParseAddress(hosts[i]); err == nil && email != nil {
template.EmailAddresses = append(template.EmailAddresses, email.Address)
} else if uri, err := url.ParseRequestURI(hosts[i]); err == nil && uri != nil {
template.URIs = append(template.URIs, uri)
} else {
template.DNSNames = append(template.DNSNames, hosts[i])
}
}
}
// Sign signs a new certificate based on the PEM-encoded client
// certificate or certificate request with the signing profile,
// specified by profileName.
func (s *Signer) Sign(req signer.SignRequest) (cert []byte, err error) {
profile, err := signer.Profile(s, req.Profile)
if err != nil {
return
}
block, _ := pem.Decode([]byte(req.Request))
if block == nil {
return nil, cferr.New(cferr.CSRError, cferr.DecodeFailed)
}
if block.Type != "NEW CERTIFICATE REQUEST" && block.Type != "CERTIFICATE REQUEST" {
return nil, cferr.Wrap(cferr.CSRError,
cferr.BadRequest, errors.New("not a csr"))
}
csrTemplate, err := signer.ParseCertificateRequest(s, block.Bytes)
if err != nil {
return nil, err
}
// Copy out only the fields from the CSR authorized by policy.
safeTemplate := x509.Certificate{}
// If the profile contains no explicit whitelist, assume that all fields
// should be copied from the CSR.
if profile.CSRWhitelist == nil {
safeTemplate = *csrTemplate
} else {
if profile.CSRWhitelist.Subject {
safeTemplate.Subject = csrTemplate.Subject
}
if profile.CSRWhitelist.PublicKeyAlgorithm {
safeTemplate.PublicKeyAlgorithm = csrTemplate.PublicKeyAlgorithm
}
if profile.CSRWhitelist.PublicKey {
safeTemplate.PublicKey = csrTemplate.PublicKey
}
if profile.CSRWhitelist.SignatureAlgorithm {
safeTemplate.SignatureAlgorithm = csrTemplate.SignatureAlgorithm
}
if profile.CSRWhitelist.DNSNames {
safeTemplate.DNSNames = csrTemplate.DNSNames
}
if profile.CSRWhitelist.IPAddresses {
safeTemplate.IPAddresses = csrTemplate.IPAddresses
}
if profile.CSRWhitelist.EmailAddresses {
safeTemplate.EmailAddresses = csrTemplate.EmailAddresses
}
if profile.CSRWhitelist.URIs {
safeTemplate.URIs = csrTemplate.URIs
}
}
if req.CRLOverride != "" {
safeTemplate.CRLDistributionPoints = []string{req.CRLOverride}
}
if safeTemplate.IsCA {
if !profile.CAConstraint.IsCA {
log.Error("local signer policy disallows issuing CA certificate")
return nil, cferr.New(cferr.PolicyError, cferr.InvalidRequest)
}
if s.ca != nil && s.ca.MaxPathLen > 0 {
if safeTemplate.MaxPathLen >= s.ca.MaxPathLen {
log.Error("local signer certificate disallows CA MaxPathLen extending")
// do not sign a cert with pathlen > current
return nil, cferr.New(cferr.PolicyError, cferr.InvalidRequest)
}
} else if s.ca != nil && s.ca.MaxPathLen == 0 && s.ca.MaxPathLenZero {
log.Error("local signer certificate disallows issuing CA certificate")
// signer has pathlen of 0, do not sign more intermediate CAs
return nil, cferr.New(cferr.PolicyError, cferr.InvalidRequest)
}
}
OverrideHosts(&safeTemplate, req.Hosts)
safeTemplate.Subject = PopulateSubjectFromCSR(req.Subject, safeTemplate.Subject)
// If there is a whitelist, ensure that both the Common Name and SAN DNSNames match
if profile.NameWhitelist != nil {
if safeTemplate.Subject.CommonName != "" {
if profile.NameWhitelist.Find([]byte(safeTemplate.Subject.CommonName)) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.UnmatchedWhitelist)
}
}
for _, name := range safeTemplate.DNSNames {
if profile.NameWhitelist.Find([]byte(name)) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.UnmatchedWhitelist)
}
}
for _, name := range safeTemplate.EmailAddresses {
if profile.NameWhitelist.Find([]byte(name)) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.UnmatchedWhitelist)
}
}
for _, name := range safeTemplate.URIs {
if profile.NameWhitelist.Find([]byte(name.String())) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.UnmatchedWhitelist)
}
}
}
if profile.ClientProvidesSerialNumbers {
if req.Serial == nil {
return nil, cferr.New(cferr.CertificateError, cferr.MissingSerial)
}
safeTemplate.SerialNumber = req.Serial
} else {
// RFC 5280 4.1.2.2:
// Certificate users MUST be able to handle serialNumber
// values up to 20 octets. Conforming CAs MUST NOT use
// serialNumber values longer than 20 octets.
//
// If CFSSL is providing the serial numbers, it makes
// sense to use the max supported size.
serialNumber := make([]byte, 20)
_, err = io.ReadFull(rand.Reader, serialNumber)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
}
// SetBytes interprets buf as the bytes of a big-endian
// unsigned integer. The leading byte should be masked
// off to ensure it isn't negative.
serialNumber[0] &= 0x7F
safeTemplate.SerialNumber = new(big.Int).SetBytes(serialNumber)
}
if len(req.Extensions) > 0 {
for _, ext := range req.Extensions {
oid := asn1.ObjectIdentifier(ext.ID)
if !profile.ExtensionWhitelist[oid.String()] {
return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
}
rawValue, err := hex.DecodeString(ext.Value)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.InvalidRequest, err)
}
safeTemplate.ExtraExtensions = append(safeTemplate.ExtraExtensions, pkix.Extension{
Id: oid,
Critical: ext.Critical,
Value: rawValue,
})
}
}
var distPoints = safeTemplate.CRLDistributionPoints
err = signer.FillTemplate(&safeTemplate, s.policy.Default, profile, req.NotBefore, req.NotAfter)
if err != nil {
return nil, err
}
if distPoints != nil && len(distPoints) > 0 {
safeTemplate.CRLDistributionPoints = distPoints
}
var certTBS = safeTemplate
if len(profile.CTLogServers) > 0 || req.ReturnPrecert {
// Add a poison extension which prevents validation
var poisonExtension = pkix.Extension{Id: signer.CTPoisonOID, Critical: true, Value: []byte{0x05, 0x00}}
var poisonedPreCert = certTBS
poisonedPreCert.ExtraExtensions = append(safeTemplate.ExtraExtensions, poisonExtension)
cert, err = s.sign(&poisonedPreCert)
if err != nil {
return
}
if req.ReturnPrecert {
return cert, nil
}
derCert, _ := pem.Decode(cert)
prechain := []ct.ASN1Cert{{Data: derCert.Bytes}, {Data: s.ca.Raw}}
var sctList []ct.SignedCertificateTimestamp
for _, server := range profile.CTLogServers {
log.Infof("submitting poisoned precertificate to %s", server)
ctclient, err := client.New(server, nil, jsonclient.Options{})
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.PrecertSubmissionFailed, err)
}
var resp *ct.SignedCertificateTimestamp
ctx := context.Background()
resp, err = ctclient.AddPreChain(ctx, prechain)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.PrecertSubmissionFailed, err)
}
sctList = append(sctList, *resp)
}
var serializedSCTList []byte
serializedSCTList, err = helpers.SerializeSCTList(sctList)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
}
// Serialize again as an octet string before embedding
serializedSCTList, err = asn1.Marshal(serializedSCTList)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
}
var SCTListExtension = pkix.Extension{Id: signer.SCTListOID, Critical: false, Value: serializedSCTList}
certTBS.ExtraExtensions = append(certTBS.ExtraExtensions, SCTListExtension)
}
var signedCert []byte
signedCert, err = s.sign(&certTBS)
if err != nil {
return nil, err
}
// Get the AKI from signedCert. This is required to support Go 1.9+.
// In prior versions of Go, x509.CreateCertificate updated the
// AuthorityKeyId of certTBS.
parsedCert, _ := helpers.ParseCertificatePEM(signedCert)
if s.dbAccessor != nil {
var certRecord = certdb.CertificateRecord{
Serial: certTBS.SerialNumber.String(),
// this relies on the specific behavior of x509.CreateCertificate
// which sets the AuthorityKeyId from the signer's SubjectKeyId
AKI: hex.EncodeToString(parsedCert.AuthorityKeyId),
CALabel: req.Label,
Status: "good",
Expiry: certTBS.NotAfter,
PEM: string(signedCert),
}
err = s.dbAccessor.InsertCertificate(certRecord)
if err != nil {
return nil, err
}
log.Debug("saved certificate with serial number ", certTBS.SerialNumber)
}
return signedCert, nil
}
// SignFromPrecert creates and signs a certificate from an existing precertificate
// that was previously signed by Signer.ca and inserts the provided SCTs into the
// new certificate. The resulting certificate will be a exact copy of the precert
// except for the removal of the poison extension and the addition of the SCT list
// extension. SignFromPrecert does not verify that the contents of the certificate
// still match the signing profile of the signer, it only requires that the precert
// was previously signed by the Signers CA.
func (s *Signer) SignFromPrecert(precert *x509.Certificate, scts []ct.SignedCertificateTimestamp) ([]byte, error) {
// Verify certificate was signed by s.ca
if err := precert.CheckSignatureFrom(s.ca); err != nil {
return nil, err
}
// Verify certificate is a precert
isPrecert := false
poisonIndex := 0
for i, ext := range precert.Extensions {
if ext.Id.Equal(signer.CTPoisonOID) {
if !ext.Critical {
return nil, cferr.New(cferr.CTError, cferr.PrecertInvalidPoison)
}
// Check extension contains ASN.1 NULL
if bytes.Compare(ext.Value, []byte{0x05, 0x00}) != 0 {
return nil, cferr.New(cferr.CTError, cferr.PrecertInvalidPoison)
}
isPrecert = true
poisonIndex = i
break
}
}
if !isPrecert {
return nil, cferr.New(cferr.CTError, cferr.PrecertMissingPoison)
}
// Serialize SCTs into list format and create extension
serializedList, err := helpers.SerializeSCTList(scts)
if err != nil {
return nil, err
}
// Serialize again as an octet string before embedding
serializedList, err = asn1.Marshal(serializedList)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
}
sctExt := pkix.Extension{Id: signer.SCTListOID, Critical: false, Value: serializedList}
// Create the new tbsCert from precert. Do explicit copies of any slices so that we don't
// use memory that may be altered by us or the caller at a later stage.
tbsCert := x509.Certificate{
SignatureAlgorithm: precert.SignatureAlgorithm,
PublicKeyAlgorithm: precert.PublicKeyAlgorithm,
PublicKey: precert.PublicKey,
Version: precert.Version,
SerialNumber: precert.SerialNumber,
Issuer: precert.Issuer,
Subject: precert.Subject,
NotBefore: precert.NotBefore,
NotAfter: precert.NotAfter,
KeyUsage: precert.KeyUsage,
BasicConstraintsValid: precert.BasicConstraintsValid,
IsCA: precert.IsCA,
MaxPathLen: precert.MaxPathLen,
MaxPathLenZero: precert.MaxPathLenZero,
PermittedDNSDomainsCritical: precert.PermittedDNSDomainsCritical,
}
if len(precert.Extensions) > 0 {
tbsCert.ExtraExtensions = make([]pkix.Extension, len(precert.Extensions))
copy(tbsCert.ExtraExtensions, precert.Extensions)
}
// Remove the poison extension from ExtraExtensions
tbsCert.ExtraExtensions = append(tbsCert.ExtraExtensions[:poisonIndex], tbsCert.ExtraExtensions[poisonIndex+1:]...)
// Insert the SCT list extension
tbsCert.ExtraExtensions = append(tbsCert.ExtraExtensions, sctExt)
// Sign the tbsCert
return s.sign(&tbsCert)
}
// Info return a populated info.Resp struct or an error.
func (s *Signer) Info(req info.Req) (resp *info.Resp, err error) {
cert, err := s.Certificate(req.Label, req.Profile)
if err != nil {
return
}
profile, err := signer.Profile(s, req.Profile)
if err != nil {
return
}
resp = new(info.Resp)
if cert.Raw != nil {
resp.Certificate = string(bytes.TrimSpace(pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw})))
}
resp.Usage = profile.Usage
resp.ExpiryString = profile.ExpiryString
return
}
// SigAlgo returns the RSA signer's signature algorithm.
func (s *Signer) SigAlgo() x509.SignatureAlgorithm {
return s.sigAlgo
}
// Certificate returns the signer's certificate.
func (s *Signer) Certificate(label, profile string) (*x509.Certificate, error) {
cert := *s.ca
return &cert, nil
}
// SetPolicy sets the signer's signature policy.
func (s *Signer) SetPolicy(policy *config.Signing) {
s.policy = policy
}
// SetDBAccessor sets the signers' cert db accessor
func (s *Signer) SetDBAccessor(dba certdb.Accessor) {
s.dbAccessor = dba
}
// GetDBAccessor returns the signers' cert db accessor
func (s *Signer) GetDBAccessor() certdb.Accessor {
return s.dbAccessor
}
// SetReqModifier does nothing for local
func (s *Signer) SetReqModifier(func(*http.Request, []byte)) {
// noop
}
// Policy returns the signer's policy.
func (s *Signer) Policy() *config.Signing {
return s.policy
}