// GetRemoteCA returns the remote endpoint's CA certificate
func GetRemoteCA(ctx context.Context, d digest.Digest, picker *picker.Picker) (RootCA, error) {
// We need a valid picker to be able to Dial to a remote CA
if picker == nil {
return RootCA{}, fmt.Errorf("valid remote address picker required")
}
// This TLS Config is intentionally using InsecureSkipVerify. Either we're
// doing TOFU, in which case we don't validate the remote CA, or we're using
// a user supplied hash to check the integrity of the CA certificate.
insecureCreds := credentials.NewTLS(&tls.Config{InsecureSkipVerify: true})
opts := []grpc.DialOption{
grpc.WithTransportCredentials(insecureCreds),
grpc.WithBackoffMaxDelay(10 * time.Second),
grpc.WithPicker(picker)}
firstAddr, err := picker.PickAddr()
if err != nil {
return RootCA{}, err
}
conn, err := grpc.Dial(firstAddr, opts...)
if err != nil {
return RootCA{}, err
}
defer conn.Close()
client := api.NewCAClient(conn)
response, err := client.GetRootCACertificate(ctx, &api.GetRootCACertificateRequest{})
if err != nil {
return RootCA{}, err
}
if d != "" {
verifier, err := digest.NewDigestVerifier(d)
if err != nil {
return RootCA{}, fmt.Errorf("unexpected error getting digest verifier: %v", err)
}
io.Copy(verifier, bytes.NewReader(response.Certificate))
if !verifier.Verified() {
return RootCA{}, fmt.Errorf("remote CA does not match fingerprint. Expected: %s", d.Hex())
}
}
// Check the validity of the remote Cert
_, err = helpers.ParseCertificatePEM(response.Certificate)
if err != nil {
return RootCA{}, err
}
// Create a Pool with our RootCACertificate
pool := x509.NewCertPool()
if !pool.AppendCertsFromPEM(response.Certificate) {
return RootCA{}, fmt.Errorf("failed to append certificate to cert pool")
}
return RootCA{Cert: response.Certificate, Pool: pool}, nil
}
// GetRemoteSignedCertificate submits a CSR together with the intended role to a remote CA server address
// available through a picker, and that is part of a CA identified by a specific certificate pool.
func GetRemoteSignedCertificate(ctx context.Context, csr []byte, role, secret string, rootCAPool *x509.CertPool, picker *picker.Picker, creds credentials.TransportAuthenticator, nodeInfo chan<- api.IssueNodeCertificateResponse) ([]byte, error) {
if rootCAPool == nil {
return nil, fmt.Errorf("valid root CA pool required")
}
if picker == nil {
return nil, fmt.Errorf("valid remote address picker required")
}
if creds == nil {
// This is our only non-MTLS request, and it happens when we are boostraping our TLS certs
// We're using CARole as server name, so an external CA doesn't also have to have ManagerRole in the cert SANs
creds = credentials.NewTLS(&tls.Config{ServerName: CARole, RootCAs: rootCAPool})
}
opts := []grpc.DialOption{
grpc.WithTransportCredentials(creds),
grpc.WithBackoffMaxDelay(10 * time.Second),
grpc.WithPicker(picker)}
firstAddr, err := picker.PickAddr()
if err != nil {
return nil, err
}
conn, err := grpc.Dial(firstAddr, opts...)
if err != nil {
return nil, err
}
defer conn.Close()
// Create a CAClient to retrieve a new Certificate
caClient := api.NewNodeCAClient(conn)
// Convert our internal string roles into an API role
apiRole, err := FormatRole(role)
if err != nil {
return nil, err
}
// Send the Request and retrieve the request token
issueRequest := &api.IssueNodeCertificateRequest{CSR: csr, Role: apiRole, Secret: secret}
issueResponse, err := caClient.IssueNodeCertificate(ctx, issueRequest)
if err != nil {
return nil, err
}
// Send back the NodeID on the nodeInfo, so the caller can know what ID was assigned by the CA
if nodeInfo != nil {
nodeInfo <- *issueResponse
}
statusRequest := &api.NodeCertificateStatusRequest{NodeID: issueResponse.NodeID}
expBackoff := events.NewExponentialBackoff(events.ExponentialBackoffConfig{
Base: time.Second,
Factor: time.Second,
Max: 30 * time.Second,
})
log.Infof("Waiting for TLS certificate to be issued...")
// Exponential backoff with Max of 30 seconds to wait for a new retry
for {
// Send the Request and retrieve the certificate
statusResponse, err := caClient.NodeCertificateStatus(ctx, statusRequest)
if err != nil {
return nil, err
}
// If the certificate was issued, return
if statusResponse.Status.State == api.IssuanceStateIssued {
if statusResponse.Certificate == nil {
return nil, fmt.Errorf("no certificate in CertificateStatus response")
}
// The certificate in the response must match the CSR
// we submitted. If we are getting a response for a
// certificate that was previously issued, we need to
// retry until the certificate gets updated per our
// current request.
if bytes.Equal(statusResponse.Certificate.CSR, csr) {
return statusResponse.Certificate.Certificate, nil
}
}
// If we're still pending, the issuance failed, or the state is unknown
// let's continue trying.
expBackoff.Failure(nil, nil)
time.Sleep(expBackoff.Proceed(nil))
}
}