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package client
import (
"bytes"
"crypto/tls"
"encoding/base64"
"encoding/json"
"encoding/pem"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"path"
"strings"
"time"
"google.golang.org/grpc"
"google.golang.org/grpc/metadata"
"github.com/golang/protobuf/ptypes"
"github.com/nsheridan/cashier/lib"
"github.com/nsheridan/cashier/proto"
"github.com/pkg/errors"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/agent"
"golang.org/x/net/context"
)
// SavePublicFiles installs the public part of the cert and key.
func SavePublicFiles(prefix string, cert *ssh.Certificate, pub ssh.PublicKey) error {
if prefix == "" {
return nil
}
pubTxt := ssh.MarshalAuthorizedKey(pub)
certPubTxt := []byte(cert.Type() + " " + base64.StdEncoding.EncodeToString(cert.Marshal()))
_prefix := prefix + "/id_" + cert.KeyId
if err := ioutil.WriteFile(_prefix+".pub", pubTxt, 0644); err != nil {
return err
}
err := ioutil.WriteFile(_prefix+"-cert.pub", certPubTxt, 0644)
return err
}
// SavePrivateFiles installs the private part of the key.
func SavePrivateFiles(prefix string, cert *ssh.Certificate, key Key) error {
if prefix == "" {
return nil
}
_prefix := prefix + "/id_" + cert.KeyId
pemBlock, err := pemBlockForKey(key)
if err != nil {
return err
}
err = ioutil.WriteFile(_prefix, pem.EncodeToMemory(pemBlock), 0600)
return err
}
// InstallCert adds the private key and signed certificate to the ssh agent.
func InstallCert(a agent.Agent, cert *ssh.Certificate, key Key) error {
t := time.Unix(int64(cert.ValidBefore), 0)
lifetime := t.Sub(time.Now()).Seconds()
comment := fmt.Sprintf("%s [Expires %s]", cert.KeyId, t)
pubcert := agent.AddedKey{
PrivateKey: key,
Certificate: cert,
Comment: comment,
LifetimeSecs: uint32(lifetime),
}
if err := a.Add(pubcert); err != nil {
return errors.Wrap(err, "unable to add cert to ssh agent")
}
privkey := agent.AddedKey{
PrivateKey: key,
Comment: comment,
LifetimeSecs: uint32(lifetime),
}
if err := a.Add(privkey); err != nil {
return errors.Wrap(err, "unable to add private key to ssh agent")
}
return nil
}
// send the signing request to the CA.
func send(s []byte, token, ca string, ValidateTLSCertificate bool) (*lib.SignResponse, error) {
transport := &http.Transport{
TLSClientConfig: &tls.Config{InsecureSkipVerify: !ValidateTLSCertificate},
}
client := &http.Client{Transport: transport}
u, err := url.Parse(ca)
if err != nil {
return nil, errors.Wrap(err, "unable to parse CA url")
}
u.Path = path.Join(u.Path, "/sign")
req, err := http.NewRequest("POST", u.String(), bytes.NewReader(s))
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", "application/json")
req.Header.Add("Accept", "application/json")
req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
resp, err := client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("Bad response from server: %s", resp.Status)
}
c := &lib.SignResponse{}
if err := json.NewDecoder(resp.Body).Decode(c); err != nil {
return nil, errors.Wrap(err, "unable to decode server response")
}
return c, nil
}
// Sign sends the public key to the CA to be signed.
func Sign(pub ssh.PublicKey, token string, message string, conf *Config) (*ssh.Certificate, error) {
validity, err := time.ParseDuration(conf.Validity)
if err != nil {
return nil, err
}
s, err := json.Marshal(&lib.SignRequest{
Key: string(lib.GetPublicKey(pub)),
ValidUntil: time.Now().Add(validity),
Message: message,
})
if err != nil {
return nil, errors.Wrap(err, "unable to create sign request")
}
resp, err := send(s, token, conf.CA, conf.ValidateTLSCertificate)
if err != nil {
return nil, errors.Wrap(err, "error sending request to CA")
}
if resp.Status != "ok" {
return nil, fmt.Errorf("bad response from CA: %s", resp.Response)
}
k, _, _, _, err := ssh.ParseAuthorizedKey([]byte(resp.Response))
if err != nil {
return nil, errors.Wrap(err, "unable to parse response")
}
cert, ok := k.(*ssh.Certificate)
if !ok {
return nil, fmt.Errorf("did not receive a valid certificate from server")
}
return cert, nil
}
// RPCSign sends the public key to the CA to be signed.
func RPCSign(pub ssh.PublicKey, token string, message string, conf *Config) (*ssh.Certificate, error) {
var opts []grpc.DialOption
var srv string
if strings.HasPrefix(conf.CA, "https://") {
srv = strings.TrimPrefix(conf.CA, "https://")
} else {
srv = strings.TrimPrefix(conf.CA, "http://")
opts = append(opts, grpc.WithInsecure())
}
conn, err := grpc.Dial(srv, opts...)
if err != nil {
return nil, err
}
defer conn.Close()
stub := proto.NewSignerClient(conn)
lifetime, err := time.ParseDuration(conf.Validity)
if err != nil {
return nil, err
}
deadline := time.Now().Add(lifetime)
ts, err := ptypes.TimestampProto(deadline)
if err != nil {
return nil, err
}
req := &proto.SignRequest{
Key: lib.GetPublicKey(pub),
ValidUntil: ts,
Message: message,
}
md := metadata.New(map[string]string{
"security": "authorization",
"payload": token,
})
r, err := stub.Sign(metadata.NewOutgoingContext(context.TODO(), md), req)
if err != nil {
return nil, err
}
k, _, _, _, err := ssh.ParseAuthorizedKey(r.Cert)
if err != nil {
return nil, err
}
cert, ok := k.(*ssh.Certificate)
if !ok {
return nil, errors.New("did not receive a valid certificate from server")
}
return cert, nil
}
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