Files
grafana/pkg/clientauth/middleware/token-exchange.go

111 lines
3.2 KiB
Go

package middleware
import (
"fmt"
"net/http"
authlib "github.com/grafana/authlib/authn"
sdkhttpclient "github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
"github.com/grafana/grafana/pkg/apimachinery/identity"
infralog "github.com/grafana/grafana/pkg/infra/log"
"github.com/grafana/grafana/pkg/setting"
)
type TokenExchangeMiddleware struct {
tokenExchangeClient authlib.TokenExchanger
}
type tokenExchangeMiddlewareImpl struct {
tokenExchangeClient authlib.TokenExchanger
audiences []string
next http.RoundTripper
}
type signerSettings struct {
token string
tokenExchangeURL string
}
var _ http.RoundTripper = &tokenExchangeMiddlewareImpl{}
func TestingTokenExchangeMiddleware(tokenExchangeClient authlib.TokenExchanger) *TokenExchangeMiddleware {
return &TokenExchangeMiddleware{
tokenExchangeClient: tokenExchangeClient,
}
}
func NewTokenExchangeMiddleware(cfg *setting.Cfg) (*TokenExchangeMiddleware, error) {
clientCfg, err := readSignerSettings(cfg)
if err != nil {
return nil, err
}
tokenExchangeClient, err := authlib.NewTokenExchangeClient(authlib.TokenExchangeConfig{
Token: clientCfg.token,
TokenExchangeURL: clientCfg.tokenExchangeURL,
})
if err != nil {
return nil, err
}
return &TokenExchangeMiddleware{
tokenExchangeClient: tokenExchangeClient,
}, nil
}
func (p *TokenExchangeMiddleware) New(audiences []string) sdkhttpclient.MiddlewareFunc {
return func(opts sdkhttpclient.Options, next http.RoundTripper) http.RoundTripper {
return &tokenExchangeMiddlewareImpl{
tokenExchangeClient: p.tokenExchangeClient,
audiences: audiences,
next: next,
}
}
}
func (m tokenExchangeMiddlewareImpl) RoundTrip(req *http.Request) (res *http.Response, e error) {
log := infralog.New("token-exchange-middleware")
user, err := identity.GetRequester(req.Context())
if err != nil {
return nil, err
}
namespace := user.GetNamespace()
if namespace == "" {
return nil, fmt.Errorf("cluster scoped resources are currently not supported")
}
log.Debug("signing request", "url", req.URL.Path, "audience", m.audiences, "namespace", namespace)
token, err := m.tokenExchangeClient.Exchange(req.Context(), authlib.TokenExchangeRequest{
Namespace: namespace,
Audiences: m.audiences,
})
if err != nil {
return nil, fmt.Errorf("failed to exchange token: %w", err)
}
req.Header.Set("X-Access-Token", "Bearer "+token.Token)
return m.next.RoundTrip(req)
}
// we exercise the below code path in OSS but would rather have it fail
// instead of documenting these non-pertinent settings and requiring mock values for them.
// hence, the error return is handled above as non-critical and a mock
// exchange client is returned.
func readSignerSettings(cfg *setting.Cfg) (*signerSettings, error) {
grpcClientAuthSection := cfg.SectionWithEnvOverrides("grpc_client_authentication")
s := &signerSettings{}
s.token = grpcClientAuthSection.Key("token").MustString("")
s.tokenExchangeURL = grpcClientAuthSection.Key("token_exchange_url").MustString("")
if s.token == "" || s.tokenExchangeURL == "" {
return nil, fmt.Errorf("authorization: missing token or tokenExchangeUrl")
}
return s, nil
}