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package main
import (
"context"
"fmt"
"io"
"log"
"net/http"
"strings"
"time"
"github.com/spiffe/go-spiffe/v2/spiffetls/tlsconfig"
"github.com/spiffe/go-spiffe/v2/svid/jwtsvid"
"github.com/spiffe/go-spiffe/v2/workloadapi"
)
const socketPath = "unix:///tmp/agent.sock"
func index(w http.ResponseWriter, r *http.Request) {
log.Println("Request received", svidClaims(r.Context()))
_, _ = io.WriteString(w, "Success!!!")
}
type authenticator struct {
// JWT Source used to verify token
jwtSource *workloadapi.JWTSource
// Expected audiences
audiences []string
}
func (a *authenticator) authenticateClient(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
fields := strings.Fields(req.Header.Get("Authorization"))
if len(fields) != 2 || fields[0] != "Bearer" {
log.Print("Malformed header")
http.Error(w, "Invalid or unsupported authorization header", http.StatusUnauthorized)
return
}
token := fields[1]
// Parse and validate token against fetched bundle from jwtSource,
// an alternative is using `workloadapi.ValidateJWTSVID` that will
// attest against SPIRE on each call and validate token
svid, err := jwtsvid.ParseAndValidate(token, a.jwtSource, a.audiences)
if err != nil {
log.Printf("Invalid token: %v\n", err)
http.Error(w, "Unauthorized", http.StatusUnauthorized)
return
}
req = req.WithContext(withSVIDClaims(req.Context(), svid.Claims))
next.ServeHTTP(w, req)
})
}
type svidClaimsKey struct{}
func withSVIDClaims(ctx context.Context, claims map[string]interface{}) context.Context {
return context.WithValue(ctx, svidClaimsKey{}, claims)
}
func svidClaims(ctx context.Context) map[string]interface{} {
claims, _ := ctx.Value(svidClaimsKey{}).(map[string]interface{})
return claims
}
func main() {
if err := run(context.Background()); err != nil {
log.Fatal(err)
}
}
func run(ctx context.Context) error {
// Create options to configure Sources to use expected socket path,
// as default sources will use value environment variable `SPIFFE_ENDPOINT_SOCKET`
clientOptions := workloadapi.WithClientOptions(workloadapi.WithAddr(socketPath))
// Create a X509Source using previously create workloadapi client
x509Source, err := workloadapi.NewX509Source(ctx, clientOptions)
if err != nil {
return fmt.Errorf("unable to create X509Source: %w", err)
}
defer x509Source.Close()
// Create a `tls.Config` with configuration to allow TLS communication with client
tlsConfig := tlsconfig.TLSServerConfig(x509Source)
server := &http.Server{
Addr: ":8443",
TLSConfig: tlsConfig,
ReadHeaderTimeout: time.Second * 10,
}
// Create a JWTSource to validate provided tokens from clients
jwtSource, err := workloadapi.NewJWTSource(ctx, clientOptions)
if err != nil {
return fmt.Errorf("unable to create JWTSource: %w", err)
}
defer jwtSource.Close()
// Add a middleware to validate presented JWT token
auth := &authenticator{
jwtSource: jwtSource,
audiences: []string{"spiffe://example.org/server"},
}
http.Handle("/", auth.authenticateClient(http.HandlerFunc(index)))
if err := server.ListenAndServeTLS("", ""); err != nil {
return fmt.Errorf("failed to serve: %w", err)
}
return nil
}
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