certificates/ca/bootstrap.go

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package ca
import (
"context"
"net/http"
"strings"
"github.com/pkg/errors"
"github.com/smallstep/cli/jose"
"gopkg.in/square/go-jose.v2/jwt"
)
type tokenClaims struct {
SHA string `json:"sha"`
jose.Claims
}
// Bootstrap is a helper function that initializes a client with the
// configuration in the bootstrap token.
func Bootstrap(token string) (*Client, error) {
tok, err := jwt.ParseSigned(token)
if err != nil {
return nil, errors.Wrap(err, "error parsing token")
}
var claims tokenClaims
if err := tok.UnsafeClaimsWithoutVerification(&claims); err != nil {
return nil, errors.Wrap(err, "error parsing ott")
}
// Validate bootstrap token
switch {
case len(claims.SHA) == 0:
return nil, errors.New("invalid bootstrap token: sha claim is not present")
case !strings.HasPrefix(strings.ToLower(claims.Audience[0]), "http"):
return nil, errors.New("invalid bootstrap token: aud claim is not a url")
}
return NewClient(claims.Audience[0], WithRootSHA256(claims.SHA))
}
// BootstrapServer is a helper function that returns an http.Server configured
// with the given address and handler, and prepared to use TLS connections. The
// certificate will automatically rotate if necessary.
//
// Usage:
// srv, err := ca.BootstrapServer(":443", token, handler)
// if err != nil {
// return err
// }
// srv.ListenAndServeTLS("", "")
func BootstrapServer(addr, token string, handler http.Handler) (*http.Server, error) {
client, err := Bootstrap(token)
if err != nil {
return nil, err
}
req, pk, err := CreateSignRequest(token)
if err != nil {
return nil, err
}
sign, err := client.Sign(req)
if err != nil {
return nil, err
}
tlsConfig, err := client.GetServerTLSConfig(context.Background(), sign, pk)
if err != nil {
return nil, err
}
return &http.Server{
Addr: addr,
Handler: handler,
TLSConfig: tlsConfig,
}, nil
}
// BootstrapClient is a helper function that using the given bootstrap token
// return an http.Client configured with a Transport prepared to do TLS
// connections using the client certificate returned by the certificate
// authority. The certificate will automatically rotate if necessary.
//
// Usage:
// client, err := ca.BootstrapClient(token)
// if err != nil {
// return err
// }
// resp, err := client.Get("https://internal.smallstep.com")
func BootstrapClient(token string) (*http.Client, error) {
client, err := Bootstrap(token)
if err != nil {
return nil, err
}
req, pk, err := CreateSignRequest(token)
if err != nil {
return nil, err
}
sign, err := client.Sign(req)
if err != nil {
return nil, err
}
transport, err := client.Transport(context.Background(), sign, pk)
if err != nil {
return nil, err
}
return &http.Client{
Transport: transport,
}, nil
}