certificates/authority/provisioner/sign_options.go
Oleksandr Kovalchuk 322200b7db
Implement modifier to set CommonName
Implement modifier which sets CommonName to the certificate if
CommonName is empty and forceCN is set in the config. Replace previous
implementation introduced in 0218018cee
with new modifier.

Closes https://github.com/smallstep/certificates/issues/259
Ref: https://github.com/smallstep/certificates/pull/260#issuecomment-628961322
2020-05-17 20:23:13 +03:00

393 lines
12 KiB
Go

package provisioner
import (
"crypto/ecdsa"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"net"
"reflect"
"time"
"github.com/pkg/errors"
"github.com/smallstep/cli/crypto/x509util"
"golang.org/x/crypto/ed25519"
)
// Options contains the options that can be passed to the Sign method. Backdate
// is automatically filled and can only be configured in the CA.
type Options struct {
NotAfter TimeDuration `json:"notAfter"`
NotBefore TimeDuration `json:"notBefore"`
Backdate time.Duration `json:"-"`
}
// SignOption is the interface used to collect all extra options used in the
// Sign method.
type SignOption interface{}
// CertificateValidator is the interface used to validate a X.509 certificate.
type CertificateValidator interface {
SignOption
Valid(cert *x509.Certificate, o Options) error
}
// CertificateRequestValidator is the interface used to validate a X.509
// certificate request.
type CertificateRequestValidator interface {
SignOption
Valid(req *x509.CertificateRequest) error
}
// ProfileModifier is the interface used to add custom options to the profile
// constructor. The options are used to modify the final certificate.
type ProfileModifier interface {
SignOption
Option(o Options) x509util.WithOption
}
// CertificateEnforcer is the interface used to modify a certificate after
// validation.
type CertificateEnforcer interface {
SignOption
Enforce(cert *x509.Certificate) error
}
// profileWithOption is a wrapper against x509util.WithOption to conform the
// interface.
type profileWithOption x509util.WithOption
func (v profileWithOption) Option(Options) x509util.WithOption {
return x509util.WithOption(v)
}
// emailOnlyIdentity is a CertificateRequestValidator that checks that the only
// SAN provided is the given email address.
type emailOnlyIdentity string
func (e emailOnlyIdentity) Valid(req *x509.CertificateRequest) error {
switch {
case len(req.DNSNames) > 0:
return errors.New("certificate request cannot contain DNS names")
case len(req.IPAddresses) > 0:
return errors.New("certificate request cannot contain IP addresses")
case len(req.URIs) > 0:
return errors.New("certificate request cannot contain URIs")
case len(req.EmailAddresses) == 0:
return errors.New("certificate request does not contain any email address")
case len(req.EmailAddresses) > 1:
return errors.New("certificate request contains too many email addresses")
case req.EmailAddresses[0] == "":
return errors.New("certificate request cannot contain an empty email address")
case req.EmailAddresses[0] != string(e):
return errors.Errorf("certificate request does not contain the valid email address, got %s, want %s", req.EmailAddresses[0], e)
default:
return nil
}
}
// defaultPublicKeyValidator validates the public key of a certificate request.
type defaultPublicKeyValidator struct{}
// Valid checks that certificate request common name matches the one configured.
func (v defaultPublicKeyValidator) Valid(req *x509.CertificateRequest) error {
switch k := req.PublicKey.(type) {
case *rsa.PublicKey:
if k.Size() < 256 {
return errors.New("rsa key in CSR must be at least 2048 bits (256 bytes)")
}
case *ecdsa.PublicKey, ed25519.PublicKey:
default:
return errors.Errorf("unrecognized public key of type '%T' in CSR", k)
}
return nil
}
// commonNameValidator validates the common name of a certificate request.
type commonNameValidator string
// Valid checks that certificate request common name matches the one configured.
// An empty common name is considered valid.
func (v commonNameValidator) Valid(req *x509.CertificateRequest) error {
if req.Subject.CommonName == "" {
return nil
}
if req.Subject.CommonName != string(v) {
return errors.Errorf("certificate request does not contain the valid common name; requested common name = %s, token subject = %s", req.Subject.CommonName, v)
}
return nil
}
// commonNameSliceValidator validates thats the common name of a certificate
// request is present in the slice. An empty common name is considered valid.
type commonNameSliceValidator []string
func (v commonNameSliceValidator) Valid(req *x509.CertificateRequest) error {
if req.Subject.CommonName == "" {
return nil
}
for _, cn := range v {
if req.Subject.CommonName == cn {
return nil
}
}
return errors.Errorf("certificate request does not contain the valid common name, got %s, want %s", req.Subject.CommonName, v)
}
// dnsNamesValidator validates the DNS names SAN of a certificate request.
type dnsNamesValidator []string
// Valid checks that certificate request DNS Names match those configured in
// the bootstrap (token) flow.
func (v dnsNamesValidator) Valid(req *x509.CertificateRequest) error {
want := make(map[string]bool)
for _, s := range v {
want[s] = true
}
got := make(map[string]bool)
for _, s := range req.DNSNames {
got[s] = true
}
if !reflect.DeepEqual(want, got) {
return errors.Errorf("certificate request does not contain the valid DNS names - got %v, want %v", req.DNSNames, v)
}
return nil
}
// ipAddressesValidator validates the IP addresses SAN of a certificate request.
type ipAddressesValidator []net.IP
// Valid checks that certificate request IP Addresses match those configured in
// the bootstrap (token) flow.
func (v ipAddressesValidator) Valid(req *x509.CertificateRequest) error {
want := make(map[string]bool)
for _, ip := range v {
want[ip.String()] = true
}
got := make(map[string]bool)
for _, ip := range req.IPAddresses {
got[ip.String()] = true
}
if !reflect.DeepEqual(want, got) {
return errors.Errorf("IP Addresses claim failed - got %v, want %v", req.IPAddresses, v)
}
return nil
}
// emailAddressesValidator validates the email address SANs of a certificate request.
type emailAddressesValidator []string
// Valid checks that certificate request IP Addresses match those configured in
// the bootstrap (token) flow.
func (v emailAddressesValidator) Valid(req *x509.CertificateRequest) error {
want := make(map[string]bool)
for _, s := range v {
want[s] = true
}
got := make(map[string]bool)
for _, s := range req.EmailAddresses {
got[s] = true
}
if !reflect.DeepEqual(want, got) {
return errors.Errorf("certificate request does not contain the valid Email Addresses - got %v, want %v", req.EmailAddresses, v)
}
return nil
}
// profileDefaultDuration is a wrapper against x509util.WithOption to conform
// the SignOption interface.
type profileDefaultDuration time.Duration
func (v profileDefaultDuration) Option(so Options) x509util.WithOption {
var backdate time.Duration
notBefore := so.NotBefore.Time()
if notBefore.IsZero() {
notBefore = now()
backdate = -1 * so.Backdate
}
notAfter := so.NotAfter.RelativeTime(notBefore)
return func(p x509util.Profile) error {
fn := x509util.WithNotBeforeAfterDuration(notBefore, notAfter, time.Duration(v))
if err := fn(p); err != nil {
return err
}
crt := p.Subject()
crt.NotBefore = crt.NotBefore.Add(backdate)
return nil
}
}
// profileLimitDuration is an x509 profile option that modifies an x509 validity
// period according to an imposed expiration time.
type profileLimitDuration struct {
def time.Duration
notAfter time.Time
}
// Option returns an x509util option that limits the validity period of a
// certificate to one that is superficially imposed.
func (v profileLimitDuration) Option(so Options) x509util.WithOption {
return func(p x509util.Profile) error {
var backdate time.Duration
n := now()
notBefore := so.NotBefore.Time()
if notBefore.IsZero() {
notBefore = n
backdate = -1 * so.Backdate
}
if notBefore.After(v.notAfter) {
return errors.Errorf("provisioning credential expiration (%s) is before "+
"requested certificate notBefore (%s)", v.notAfter, notBefore)
}
notAfter := so.NotAfter.RelativeTime(notBefore)
if notAfter.After(v.notAfter) {
return errors.Errorf("provisioning credential expiration (%s) is before "+
"requested certificate notAfter (%s)", v.notAfter, notBefore)
}
if notAfter.IsZero() {
t := notBefore.Add(v.def)
if t.After(v.notAfter) {
notAfter = v.notAfter
} else {
notAfter = t
}
}
crt := p.Subject()
crt.NotBefore = notBefore.Add(backdate)
crt.NotAfter = notAfter
return nil
}
}
// validityValidator validates the certificate validity settings.
type validityValidator struct {
min time.Duration
max time.Duration
}
// newValidityValidator return a new validity validator.
func newValidityValidator(min, max time.Duration) *validityValidator {
return &validityValidator{min: min, max: max}
}
// Valid validates the certificate validity settings (notBefore/notAfter) and
// and total duration.
func (v *validityValidator) Valid(cert *x509.Certificate, o Options) error {
var (
na = cert.NotAfter.Truncate(time.Second)
nb = cert.NotBefore.Truncate(time.Second)
now = time.Now().Truncate(time.Second)
)
d := na.Sub(nb)
if na.Before(now) {
return errors.Errorf("notAfter cannot be in the past; na=%v", na)
}
if na.Before(nb) {
return errors.Errorf("notAfter cannot be before notBefore; na=%v, nb=%v", na, nb)
}
if d < v.min {
return errors.Errorf("requested duration of %v is less than the authorized minimum certificate duration of %v",
d, v.min)
}
// NOTE: this check is not "technically correct". We're allowing the max
// duration of a cert to be "max + backdate" and not all certificates will
// be backdated (e.g. if a user passes the NotBefore value then we do not
// apply a backdate). This is good enough.
if d > v.max+o.Backdate {
return errors.Errorf("requested duration of %v is more than the authorized maximum certificate duration of %v",
d, v.max+o.Backdate)
}
return nil
}
var (
stepOIDRoot = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 37476, 9000, 64}
stepOIDProvisioner = append(asn1.ObjectIdentifier(nil), append(stepOIDRoot, 1)...)
)
type stepProvisionerASN1 struct {
Type int
Name []byte
CredentialID []byte
KeyValuePairs []string `asn1:"optional,omitempty"`
}
type forceCNOption struct {
ForceCN bool
}
func newForceCNOption(forceCN bool) *forceCNOption {
return &forceCNOption{forceCN}
}
func (o *forceCNOption) Option(Options) x509util.WithOption {
return func(p x509util.Profile) error {
if !o.ForceCN {
// Forcing CN is disabled, do nothing to certificate
return nil
}
crt := p.Subject()
if crt.Subject.CommonName == "" {
if len(crt.DNSNames) > 0 {
crt.Subject.CommonName = crt.DNSNames[0]
} else {
return errors.New("Cannot force CN, DNSNames is empty")
}
}
return nil
}
}
type provisionerExtensionOption struct {
Type int
Name string
CredentialID string
KeyValuePairs []string
}
func newProvisionerExtensionOption(typ Type, name, credentialID string, keyValuePairs ...string) *provisionerExtensionOption {
return &provisionerExtensionOption{
Type: int(typ),
Name: name,
CredentialID: credentialID,
KeyValuePairs: keyValuePairs,
}
}
func (o *provisionerExtensionOption) Option(Options) x509util.WithOption {
return func(p x509util.Profile) error {
crt := p.Subject()
ext, err := createProvisionerExtension(o.Type, o.Name, o.CredentialID, o.KeyValuePairs...)
if err != nil {
return err
}
crt.ExtraExtensions = append(crt.ExtraExtensions, ext)
return nil
}
}
func createProvisionerExtension(typ int, name, credentialID string, keyValuePairs ...string) (pkix.Extension, error) {
b, err := asn1.Marshal(stepProvisionerASN1{
Type: typ,
Name: []byte(name),
CredentialID: []byte(credentialID),
KeyValuePairs: keyValuePairs,
})
if err != nil {
return pkix.Extension{}, errors.Wrapf(err, "error marshaling provisioner extension")
}
return pkix.Extension{
Id: stepOIDProvisioner,
Critical: false,
Value: b,
}, nil
}
func init() {
// Avoid dead-code warning in profileWithOption
_ = profileWithOption(nil)
}