package ca import ( "encoding/json" "net/url" "time" "github.com/pkg/errors" "github.com/smallstep/certificates/authority/provisioner" "github.com/smallstep/cli/token" "github.com/smallstep/cli/token/provision" "go.step.sm/crypto/jose" "go.step.sm/crypto/randutil" ) const tokenLifetime = 5 * time.Minute // Provisioner is an authorized entity that can sign tokens necessary for // signature requests. type Provisioner struct { *Client name string kid string audience string sshAudience string fingerprint string jwk *jose.JSONWebKey tokenLifetime time.Duration } // NewProvisioner loads and decrypts key material from the CA for the named // provisioner. The key identified by `kid` will be used if specified. If `kid` // is the empty string we'll use the first key for the named provisioner that // decrypts using `password`. func NewProvisioner(name, kid, caURL string, password []byte, opts ...ClientOption) (*Provisioner, error) { client, err := NewClient(caURL, opts...) if err != nil { return nil, err } // Get the fingerprint of the current connection fp, err := client.RootFingerprint() if err != nil { return nil, err } var jwk *jose.JSONWebKey switch { case name == "": return nil, errors.New("provisioner name cannot be empty") case kid == "": jwk, err = loadProvisionerJWKByName(client, name, password) default: jwk, err = loadProvisionerJWKByKid(client, kid, password) } if err != nil { return nil, err } return &Provisioner{ Client: client, name: name, kid: jwk.KeyID, audience: client.endpoint.ResolveReference(&url.URL{Path: "/1.0/sign"}).String(), sshAudience: client.endpoint.ResolveReference(&url.URL{Path: "/1.0/ssh/sign"}).String(), fingerprint: fp, jwk: jwk, tokenLifetime: tokenLifetime, }, nil } // Name returns the provisioner's name. func (p *Provisioner) Name() string { return p.name } // Kid returns the provisioners key ID. func (p *Provisioner) Kid() string { return p.kid } // SetFingerprint overwrites the default fingerprint used. func (p *Provisioner) SetFingerprint(sum string) { p.fingerprint = sum } // Token generates a bootstrap token for a subject. func (p *Provisioner) Token(subject string, sans ...string) (string, error) { if len(sans) == 0 { sans = []string{subject} } // A random jwt id will be used to identify duplicated tokens jwtID, err := randutil.Hex(64) // 256 bits if err != nil { return "", err } notBefore := time.Now() notAfter := notBefore.Add(tokenLifetime) tokOptions := []token.Options{ token.WithJWTID(jwtID), token.WithKid(p.kid), token.WithIssuer(p.name), token.WithAudience(p.audience), token.WithValidity(notBefore, notAfter), token.WithSANS(sans), } if p.fingerprint != "" { tokOptions = append(tokOptions, token.WithSHA(p.fingerprint)) } tok, err := provision.New(subject, tokOptions...) if err != nil { return "", err } return tok.SignedString(p.jwk.Algorithm, p.jwk.Key) } // SSHToken generates a SSH token. func (p *Provisioner) SSHToken(certType, keyID string, principals []string) (string, error) { jwtID, err := randutil.Hex(64) if err != nil { return "", err } notBefore := time.Now() notAfter := notBefore.Add(tokenLifetime) tokOptions := []token.Options{ token.WithJWTID(jwtID), token.WithKid(p.kid), token.WithIssuer(p.name), token.WithAudience(p.sshAudience), token.WithValidity(notBefore, notAfter), token.WithSSH(provisioner.SignSSHOptions{ CertType: certType, Principals: principals, KeyID: keyID, }), } if p.fingerprint != "" { tokOptions = append(tokOptions, token.WithSHA(p.fingerprint)) } tok, err := provision.New(keyID, tokOptions...) if err != nil { return "", err } return tok.SignedString(p.jwk.Algorithm, p.jwk.Key) } func decryptProvisionerJWK(encryptedKey string, password []byte) (*jose.JSONWebKey, error) { enc, err := jose.ParseEncrypted(encryptedKey) if err != nil { return nil, err } data, err := enc.Decrypt(password) if err != nil { return nil, err } jwk := new(jose.JSONWebKey) if err := json.Unmarshal(data, jwk); err != nil { return nil, errors.Wrap(err, "error unmarshaling provisioning key") } return jwk, nil } // loadProvisionerJWKByKid retrieves a provisioner key from the CA by key ID and // decrypts it using the specified password. func loadProvisionerJWKByKid(client *Client, kid string, password []byte) (*jose.JSONWebKey, error) { encrypted, err := getProvisionerKey(client, kid) if err != nil { return nil, err } return decryptProvisionerJWK(encrypted, password) } // loadProvisionerJWKByName retrieves the list of provisioners and encrypted key then // returns the key of the first provisioner with a matching name that can be successfully // decrypted with the specified password. func loadProvisionerJWKByName(client *Client, name string, password []byte) (key *jose.JSONWebKey, err error) { provisioners, err := getProvisioners(client) if err != nil { err = errors.Wrap(err, "error getting the provisioners") return } for _, provisioner := range provisioners { if provisioner.GetName() == name { if _, encryptedKey, ok := provisioner.GetEncryptedKey(); ok { key, err = decryptProvisionerJWK(encryptedKey, password) if err == nil { return } } } } return nil, errors.Errorf("provisioner '%s' not found (or your password is wrong)", name) } // getProvisioners returns the list of provisioners using the configured client. func getProvisioners(client *Client) (provisioner.List, error) { var cursor string var provisioners provisioner.List for { resp, err := client.Provisioners(WithProvisionerCursor(cursor), WithProvisionerLimit(100)) if err != nil { return nil, err } provisioners = append(provisioners, resp.Provisioners...) if resp.NextCursor == "" { return provisioners, nil } cursor = resp.NextCursor } } // getProvisionerKey returns the encrypted provisioner key for the given kid. func getProvisionerKey(client *Client, kid string) (string, error) { resp, err := client.ProvisionerKey(kid) if err != nil { return "", err } return resp.Key, nil }