forked from TrueCloudLab/certificates
551 lines
18 KiB
Go
551 lines
18 KiB
Go
package cloudcas
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import (
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"context"
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"crypto/rand"
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"crypto/x509"
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"encoding/asn1"
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"encoding/pem"
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"regexp"
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"strings"
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"time"
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privateca "cloud.google.com/go/security/privateca/apiv1beta1"
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"github.com/google/uuid"
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gax "github.com/googleapis/gax-go/v2"
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"github.com/pkg/errors"
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"github.com/smallstep/certificates/cas/apiv1"
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"google.golang.org/api/option"
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pb "google.golang.org/genproto/googleapis/cloud/security/privateca/v1beta1"
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durationpb "google.golang.org/protobuf/types/known/durationpb"
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)
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func init() {
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apiv1.Register(apiv1.CloudCAS, func(ctx context.Context, opts apiv1.Options) (apiv1.CertificateAuthorityService, error) {
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return New(ctx, opts)
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})
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}
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// The actual regular expression that matches a certificate authority is:
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// ^projects/[a-z][a-z0-9-]{4,28}[a-z0-9]/locations/[a-z0-9-]+/certificateAuthorities/[a-zA-Z0-9-_]+$
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// But we will allow a more flexible one to fail if this changes.
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var caRegexp = regexp.MustCompile("^projects/[^/]+/locations/[^/]+/certificateAuthorities/[^/]+$")
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// CertificateAuthorityClient is the interface implemented by the Google CAS
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// client.
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type CertificateAuthorityClient interface {
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CreateCertificate(ctx context.Context, req *pb.CreateCertificateRequest, opts ...gax.CallOption) (*pb.Certificate, error)
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RevokeCertificate(ctx context.Context, req *pb.RevokeCertificateRequest, opts ...gax.CallOption) (*pb.Certificate, error)
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GetCertificateAuthority(ctx context.Context, req *pb.GetCertificateAuthorityRequest, opts ...gax.CallOption) (*pb.CertificateAuthority, error)
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CreateCertificateAuthority(ctx context.Context, req *pb.CreateCertificateAuthorityRequest, opts ...gax.CallOption) (*privateca.CreateCertificateAuthorityOperation, error)
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FetchCertificateAuthorityCsr(ctx context.Context, req *pb.FetchCertificateAuthorityCsrRequest, opts ...gax.CallOption) (*pb.FetchCertificateAuthorityCsrResponse, error)
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ActivateCertificateAuthority(ctx context.Context, req *pb.ActivateCertificateAuthorityRequest, opts ...gax.CallOption) (*privateca.ActivateCertificateAuthorityOperation, error)
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}
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// recocationCodeMap maps revocation reason codes from RFC 5280, to Google CAS
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// revocation reasons. Revocation reason 7 is not used, and revocation reason 8
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// (removeFromCRL) is not supported by Google CAS.
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var revocationCodeMap = map[int]pb.RevocationReason{
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0: pb.RevocationReason_REVOCATION_REASON_UNSPECIFIED,
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1: pb.RevocationReason_KEY_COMPROMISE,
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2: pb.RevocationReason_CERTIFICATE_AUTHORITY_COMPROMISE,
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3: pb.RevocationReason_AFFILIATION_CHANGED,
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4: pb.RevocationReason_SUPERSEDED,
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5: pb.RevocationReason_CESSATION_OF_OPERATION,
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6: pb.RevocationReason_CERTIFICATE_HOLD,
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9: pb.RevocationReason_PRIVILEGE_WITHDRAWN,
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10: pb.RevocationReason_ATTRIBUTE_AUTHORITY_COMPROMISE,
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}
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// CloudCAS implements a Certificate Authority Service using Google Cloud CAS.
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type CloudCAS struct {
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client CertificateAuthorityClient
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certificateAuthority string
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project string
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location string
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}
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// newCertificateAuthorityClient creates the certificate authority client. This
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// function is used for testing purposes.
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var newCertificateAuthorityClient = func(ctx context.Context, credentialsFile string) (CertificateAuthorityClient, error) {
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var cloudOpts []option.ClientOption
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if credentialsFile != "" {
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cloudOpts = append(cloudOpts, option.WithCredentialsFile(credentialsFile))
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}
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client, err := privateca.NewCertificateAuthorityClient(ctx, cloudOpts...)
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if err != nil {
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return nil, errors.Wrap(err, "error creating client")
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}
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return client, nil
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}
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// New creates a new CertificateAuthorityService implementation using Google
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// Cloud CAS.
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func New(ctx context.Context, opts apiv1.Options) (*CloudCAS, error) {
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if opts.IsCreator {
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switch {
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case opts.Project == "":
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return nil, errors.New("cloudCAS 'project' cannot be empty")
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case opts.Location == "":
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return nil, errors.New("cloudCAS 'location' cannot be empty")
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}
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} else {
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if opts.CertificateAuthority == "" {
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return nil, errors.New("cloudCAS 'certificateAuthority' cannot be empty")
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}
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if !caRegexp.MatchString(opts.CertificateAuthority) {
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return nil, errors.New("cloudCAS 'certificateAuthority' is not valid certificate authority resource")
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}
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// Extract project and location from CertificateAuthority
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if parts := strings.Split(opts.CertificateAuthority, "/"); len(parts) == 6 {
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if opts.Project == "" {
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opts.Project = parts[1]
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}
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if opts.Location == "" {
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opts.Location = parts[3]
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}
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}
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}
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client, err := newCertificateAuthorityClient(ctx, opts.CredentialsFile)
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if err != nil {
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return nil, err
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}
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return &CloudCAS{
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client: client,
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certificateAuthority: opts.CertificateAuthority,
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project: opts.Project,
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location: opts.Location,
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}, nil
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}
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// GetCertificateAuthority returns the root certificate for the given
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// certificate authority. It implements apiv1.CertificateAuthorityGetter
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// interface.
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func (c *CloudCAS) GetCertificateAuthority(req *apiv1.GetCertificateAuthorityRequest) (*apiv1.GetCertificateAuthorityResponse, error) {
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name := req.Name
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if name == "" {
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name = c.certificateAuthority
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}
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ctx, cancel := defaultContext()
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defer cancel()
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resp, err := c.client.GetCertificateAuthority(ctx, &pb.GetCertificateAuthorityRequest{
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Name: name,
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})
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if err != nil {
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println(name)
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return nil, errors.Wrap(err, "cloudCAS GetCertificateAuthority failed")
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}
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if len(resp.PemCaCertificates) == 0 {
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return nil, errors.New("cloudCAS GetCertificateAuthority: PemCACertificate should not be empty")
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}
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// Last certificate in the chain is the root.
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root, err := parseCertificate(resp.PemCaCertificates[len(resp.PemCaCertificates)-1])
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if err != nil {
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return nil, err
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}
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return &apiv1.GetCertificateAuthorityResponse{
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RootCertificate: root,
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}, nil
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}
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// CreateCertificate signs a new certificate using Google Cloud CAS.
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func (c *CloudCAS) CreateCertificate(req *apiv1.CreateCertificateRequest) (*apiv1.CreateCertificateResponse, error) {
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switch {
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case req.Template == nil:
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return nil, errors.New("createCertificateRequest `template` cannot be nil")
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case req.Lifetime == 0:
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return nil, errors.New("createCertificateRequest `lifetime` cannot be 0")
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}
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cert, chain, err := c.createCertificate(req.Template, req.Lifetime, req.RequestID)
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if err != nil {
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return nil, err
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}
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return &apiv1.CreateCertificateResponse{
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Certificate: cert,
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CertificateChain: chain,
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}, nil
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}
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// RenewCertificate renews the given certificate using Google Cloud CAS.
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// Google's CAS does not support the renew operation, so this method uses
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// CreateCertificate.
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func (c *CloudCAS) RenewCertificate(req *apiv1.RenewCertificateRequest) (*apiv1.RenewCertificateResponse, error) {
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switch {
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case req.Template == nil:
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return nil, errors.New("renewCertificateRequest `template` cannot be nil")
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case req.Lifetime == 0:
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return nil, errors.New("renewCertificateRequest `lifetime` cannot be 0")
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}
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cert, chain, err := c.createCertificate(req.Template, req.Lifetime, req.RequestID)
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if err != nil {
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return nil, err
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}
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return &apiv1.RenewCertificateResponse{
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Certificate: cert,
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CertificateChain: chain,
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}, nil
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}
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// RevokeCertificate revokes a certificate using Google Cloud CAS.
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func (c *CloudCAS) RevokeCertificate(req *apiv1.RevokeCertificateRequest) (*apiv1.RevokeCertificateResponse, error) {
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reason, ok := revocationCodeMap[req.ReasonCode]
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switch {
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case !ok:
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return nil, errors.Errorf("revokeCertificate 'reasonCode=%d' is invalid or not supported", req.ReasonCode)
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case req.Certificate == nil:
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return nil, errors.New("revokeCertificateRequest `certificate` cannot be nil")
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}
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ext, ok := apiv1.FindCertificateAuthorityExtension(req.Certificate)
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if !ok {
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return nil, errors.New("error revoking certificate: certificate authority extension was not found")
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}
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var cae apiv1.CertificateAuthorityExtension
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if _, err := asn1.Unmarshal(ext.Value, &cae); err != nil {
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return nil, errors.Wrap(err, "error unmarshaling certificate authority extension")
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}
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ctx, cancel := defaultContext()
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defer cancel()
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certpb, err := c.client.RevokeCertificate(ctx, &pb.RevokeCertificateRequest{
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Name: c.certificateAuthority + "/certificates/" + cae.CertificateID,
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Reason: reason,
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RequestId: req.RequestID,
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})
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS RevokeCertificate failed")
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}
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cert, chain, err := getCertificateAndChain(certpb)
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if err != nil {
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return nil, err
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}
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return &apiv1.RevokeCertificateResponse{
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Certificate: cert,
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CertificateChain: chain,
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}, nil
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}
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// CreateCertificateAuthority creates a new root or intermediate certificate
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// using Google Cloud CAS.
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func (c *CloudCAS) CreateCertificateAuthority(req *apiv1.CreateCertificateAuthorityRequest) (*apiv1.CreateCertificateAuthorityResponse, error) {
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switch {
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case c.project == "":
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return nil, errors.New("cloudCAS `project` cannot be empty")
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case c.location == "":
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return nil, errors.New("cloudCAS `location` cannot be empty")
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case req.Template == nil:
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return nil, errors.New("createCertificateAuthorityRequest `template` cannot be nil")
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case req.Lifetime == 0:
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return nil, errors.New("createCertificateAuthorityRequest `lifetime` cannot be 0")
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case req.Type == apiv1.IntermediateCA && req.Parent == nil:
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return nil, errors.New("createCertificateAuthorityRequest `parent` cannot be nil")
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case req.Type == apiv1.IntermediateCA && req.Parent.Name == "":
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return nil, errors.New("createCertificateAuthorityRequest `parent.name` cannot be empty")
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}
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// Select key and signature algorithm to use
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var err error
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var keySpec *pb.CertificateAuthority_KeyVersionSpec
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if req.CreateKey == nil {
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if keySpec, err = createKeyVersionSpec(0, 0); err != nil {
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return nil, errors.Wrap(err, "createCertificateAuthorityRequest `createKey` is not valid")
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}
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} else {
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if keySpec, err = createKeyVersionSpec(req.CreateKey.SignatureAlgorithm, req.CreateKey.Bits); err != nil {
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return nil, errors.Wrap(err, "createCertificateAuthorityRequest `createKey` is not valid")
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}
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}
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// Normalize or generate id.
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certificateAuthorityID := normalizeCertificateAuthorityName(req.Name)
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if certificateAuthorityID == "" {
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id, err := createCertificateID()
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if err != nil {
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return nil, err
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}
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certificateAuthorityID = id
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}
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// Add CertificateAuthority extension
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casExtension, err := apiv1.CreateCertificateAuthorityExtension(apiv1.CloudCAS, certificateAuthorityID)
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if err != nil {
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return nil, err
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}
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req.Template.ExtraExtensions = append(req.Template.ExtraExtensions, casExtension)
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// Prepare CreateCertificateAuthorityRequest
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pbReq := &pb.CreateCertificateAuthorityRequest{
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Parent: "projects/" + c.project + "/locations/" + c.location,
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CertificateAuthorityId: certificateAuthorityID,
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RequestId: req.RequestID,
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CertificateAuthority: &pb.CertificateAuthority{
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Type: pb.CertificateAuthority_TYPE_UNSPECIFIED,
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Tier: pb.CertificateAuthority_ENTERPRISE,
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Config: &pb.CertificateConfig{
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SubjectConfig: &pb.CertificateConfig_SubjectConfig{
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Subject: createSubject(req.Template),
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CommonName: req.Template.Subject.CommonName,
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},
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ReusableConfig: createReusableConfig(req.Template),
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},
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Lifetime: durationpb.New(req.Lifetime),
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KeySpec: keySpec,
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IssuingOptions: &pb.CertificateAuthority_IssuingOptions{
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IncludeCaCertUrl: true,
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IncludeCrlAccessUrl: true,
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},
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Labels: map[string]string{},
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},
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}
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switch req.Type {
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case apiv1.RootCA:
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pbReq.CertificateAuthority.Type = pb.CertificateAuthority_SELF_SIGNED
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case apiv1.IntermediateCA:
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pbReq.CertificateAuthority.Type = pb.CertificateAuthority_SUBORDINATE
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default:
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return nil, errors.Errorf("createCertificateAuthorityRequest `type=%d' is invalid or not supported", req.Type)
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}
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// Create certificate authority.
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ctx, cancel := defaultContext()
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defer cancel()
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resp, err := c.client.CreateCertificateAuthority(ctx, pbReq)
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS CreateCertificateAuthority failed")
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}
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// Wait for the long-running operation.
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ctx, cancel = defaultInitiatorContext()
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defer cancel()
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ca, err := resp.Wait(ctx)
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS CreateCertificateAuthority failed")
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}
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// Sign Intermediate CAs with the parent.
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if req.Type == apiv1.IntermediateCA {
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ca, err = c.signIntermediateCA(ca.Name, req)
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if err != nil {
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return nil, err
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}
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}
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if len(ca.PemCaCertificates) == 0 {
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return nil, errors.New("cloudCAS CreateCertificateAuthority failed: PemCaCertificates is empty")
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}
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cert, err := parseCertificate(ca.PemCaCertificates[0])
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if err != nil {
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return nil, err
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}
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var chain []*x509.Certificate
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if pemChain := ca.PemCaCertificates[1:]; len(pemChain) > 0 {
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chain = make([]*x509.Certificate, len(pemChain))
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for i, s := range pemChain {
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if chain[i], err = parseCertificate(s); err != nil {
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return nil, err
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}
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}
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}
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return &apiv1.CreateCertificateAuthorityResponse{
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Name: ca.Name,
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Certificate: cert,
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CertificateChain: chain,
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}, nil
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}
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func (c *CloudCAS) createCertificate(tpl *x509.Certificate, lifetime time.Duration, requestID string) (*x509.Certificate, []*x509.Certificate, error) {
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// Removes the CAS extension if it exists.
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apiv1.RemoveCertificateAuthorityExtension(tpl)
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// Create new CAS extension with the certificate id.
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id, err := createCertificateID()
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if err != nil {
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return nil, nil, err
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}
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casExtension, err := apiv1.CreateCertificateAuthorityExtension(apiv1.CloudCAS, id)
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if err != nil {
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return nil, nil, err
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}
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tpl.ExtraExtensions = append(tpl.ExtraExtensions, casExtension)
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// Create and submit certificate
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certConfig, err := createCertificateConfig(tpl)
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if err != nil {
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return nil, nil, err
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}
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ctx, cancel := defaultContext()
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defer cancel()
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cert, err := c.client.CreateCertificate(ctx, &pb.CreateCertificateRequest{
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Parent: c.certificateAuthority,
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CertificateId: id,
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Certificate: &pb.Certificate{
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CertificateConfig: certConfig,
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Lifetime: durationpb.New(lifetime),
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Labels: map[string]string{},
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},
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RequestId: requestID,
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})
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if err != nil {
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return nil, nil, errors.Wrap(err, "cloudCAS CreateCertificate failed")
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}
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// Return certificate and certificate chain
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return getCertificateAndChain(cert)
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}
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func (c *CloudCAS) signIntermediateCA(name string, req *apiv1.CreateCertificateAuthorityRequest) (*pb.CertificateAuthority, error) {
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id, err := createCertificateID()
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if err != nil {
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return nil, err
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}
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// Fetch intermediate CSR
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ctx, cancel := defaultInitiatorContext()
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defer cancel()
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csr, err := c.client.FetchCertificateAuthorityCsr(ctx, &pb.FetchCertificateAuthorityCsrRequest{
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Name: name,
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})
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS FetchCertificateAuthorityCsr failed")
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}
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// Sign the CSR with the ca.
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ctx, cancel = defaultInitiatorContext()
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defer cancel()
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sign, err := c.client.CreateCertificate(ctx, &pb.CreateCertificateRequest{
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Parent: req.Parent.Name,
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CertificateId: id,
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Certificate: &pb.Certificate{
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// Name: "projects/" + c.project + "/locations/" + c.location + "/certificates/" + id,
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CertificateConfig: &pb.Certificate_PemCsr{
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PemCsr: csr.PemCsr,
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},
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Lifetime: durationpb.New(req.Lifetime),
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Labels: map[string]string{},
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},
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RequestId: req.RequestID,
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})
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS CreateCertificate failed")
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}
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ctx, cancel = defaultInitiatorContext()
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defer cancel()
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resp, err := c.client.ActivateCertificateAuthority(ctx, &pb.ActivateCertificateAuthorityRequest{
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Name: name,
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PemCaCertificate: sign.PemCertificate,
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SubordinateConfig: &pb.SubordinateConfig{
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SubordinateConfig: &pb.SubordinateConfig_PemIssuerChain{
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PemIssuerChain: &pb.SubordinateConfig_SubordinateConfigChain{
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PemCertificates: sign.PemCertificateChain,
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},
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},
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},
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RequestId: req.RequestID,
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})
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS ActivateCertificateAuthority1 failed")
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}
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// Wait for the long-running operation.
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ctx, cancel = defaultInitiatorContext()
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defer cancel()
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ca, err := resp.Wait(ctx)
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if err != nil {
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return nil, errors.Wrap(err, "cloudCAS ActivateCertificateAuthority failed")
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}
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return ca, nil
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}
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func defaultContext() (context.Context, context.CancelFunc) {
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return context.WithTimeout(context.Background(), 15*time.Second)
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}
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func defaultInitiatorContext() (context.Context, context.CancelFunc) {
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return context.WithTimeout(context.Background(), 60*time.Second)
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}
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func createCertificateID() (string, error) {
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id, err := uuid.NewRandomFromReader(rand.Reader)
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if err != nil {
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return "", errors.Wrap(err, "error creating certificate id")
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}
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return id.String(), nil
|
|
}
|
|
|
|
func parseCertificate(pemCert string) (*x509.Certificate, error) {
|
|
block, _ := pem.Decode([]byte(pemCert))
|
|
if block == nil {
|
|
return nil, errors.New("error decoding certificate: not a valid PEM encoded block")
|
|
}
|
|
cert, err := x509.ParseCertificate(block.Bytes)
|
|
if err != nil {
|
|
return nil, errors.Wrap(err, "error parsing certificate")
|
|
}
|
|
return cert, nil
|
|
}
|
|
|
|
func getCertificateAndChain(certpb *pb.Certificate) (*x509.Certificate, []*x509.Certificate, error) {
|
|
cert, err := parseCertificate(certpb.PemCertificate)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
pemChain := certpb.PemCertificateChain[:len(certpb.PemCertificateChain)-1]
|
|
chain := make([]*x509.Certificate, len(pemChain))
|
|
for i := range pemChain {
|
|
chain[i], err = parseCertificate(pemChain[i])
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
}
|
|
|
|
return cert, chain, nil
|
|
|
|
}
|
|
|
|
// Normalize a certificate authority name to comply with [a-zA-Z0-9-_].
|
|
func normalizeCertificateAuthorityName(name string) string {
|
|
return strings.Map(func(r rune) rune {
|
|
switch {
|
|
case r >= 'a' && r <= 'z':
|
|
return r
|
|
case r >= 'A' && r <= 'Z':
|
|
return r
|
|
case r >= '0' && r <= '9':
|
|
return r
|
|
case r == '-':
|
|
return r
|
|
case r == '_':
|
|
return r
|
|
default:
|
|
return '-'
|
|
}
|
|
}, name)
|
|
}
|