open-vault/command/agent/auth/kubernetes/kubernetes.go
Becca Petrin c2894b8d05
Add Kerberos auth agent (#7999)
* add kerberos auth agent

* strip old comment

* changes from feedback

* strip appengine indirect dependency
2020-01-09 14:56:34 -08:00

131 lines
3.1 KiB
Go

package kubernetes
import (
"context"
"errors"
"fmt"
"io"
"io/ioutil"
"net/http"
"os"
"strings"
"github.com/hashicorp/errwrap"
hclog "github.com/hashicorp/go-hclog"
"github.com/hashicorp/vault/api"
"github.com/hashicorp/vault/command/agent/auth"
)
const (
serviceAccountFile = "/var/run/secrets/kubernetes.io/serviceaccount/token"
)
type kubernetesMethod struct {
logger hclog.Logger
mountPath string
role string
// tokenPath is an optional path to a projected service account token inside
// the pod, for use instead of the default service account token.
tokenPath string
// jwtData is a ReadCloser used to inject a ReadCloser for mocking tests.
jwtData io.ReadCloser
}
// NewKubernetesAuthMethod reads the user configuration and returns a configured
// AuthMethod
func NewKubernetesAuthMethod(conf *auth.AuthConfig) (auth.AuthMethod, error) {
if conf == nil {
return nil, errors.New("empty config")
}
if conf.Config == nil {
return nil, errors.New("empty config data")
}
k := &kubernetesMethod{
logger: conf.Logger,
mountPath: conf.MountPath,
}
roleRaw, ok := conf.Config["role"]
if !ok {
return nil, errors.New("missing 'role' value")
}
k.role, ok = roleRaw.(string)
if !ok {
return nil, errors.New("could not convert 'role' config value to string")
}
tokenPathRaw, ok := conf.Config["token_path"]
if ok {
k.tokenPath, ok = tokenPathRaw.(string)
if !ok {
return nil, errors.New("could not convert 'token_path' config value to string")
}
}
if k.role == "" {
return nil, errors.New("'role' value is empty")
}
return k, nil
}
func (k *kubernetesMethod) Authenticate(ctx context.Context, client *api.Client) (string, http.Header, map[string]interface{}, error) {
k.logger.Trace("beginning authentication")
jwtString, err := k.readJWT()
if err != nil {
return "", nil, nil, errwrap.Wrapf("error reading JWT with Kubernetes Auth: {{err}}", err)
}
return fmt.Sprintf("%s/login", k.mountPath), nil, map[string]interface{}{
"role": k.role,
"jwt": jwtString,
}, nil
}
func (k *kubernetesMethod) NewCreds() chan struct{} {
return nil
}
func (k *kubernetesMethod) CredSuccess() {
}
func (k *kubernetesMethod) Shutdown() {
}
// readJWT reads the JWT data for the Agent to submit to Vault. The default is
// to read the JWT from the default service account location, defined by the
// constant serviceAccountFile. In normal use k.jwtData is nil at invocation and
// the method falls back to reading the token path with os.Open, opening a file
// from either the default location or from the token_path path specified in
// configuration.
func (k *kubernetesMethod) readJWT() (string, error) {
// load configured token path if set, default to serviceAccountFile
tokenFilePath := serviceAccountFile
if k.tokenPath != "" {
tokenFilePath = k.tokenPath
}
data := k.jwtData
// k.jwtData should only be non-nil in tests
if data == nil {
f, err := os.Open(tokenFilePath)
if err != nil {
return "", err
}
data = f
}
defer data.Close()
contentBytes, err := ioutil.ReadAll(data)
if err != nil {
return "", err
}
return strings.TrimSpace(string(contentBytes)), nil
}