Add command line tool to verify remote enclave.

cmd/veil-verify/main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+
+	"github.com/Amnesic-Systems/veil/internal/enclave"
+	"github.com/Amnesic-Systems/veil/internal/errs"
+	"github.com/Amnesic-Systems/veil/internal/httputil"
+	"github.com/Amnesic-Systems/veil/internal/nonce"
+)
+
+type config struct {
+	Addr    string
+	Testing bool
+}
+
+func parseFlags(out io.Writer, args []string) (*config, error) {
+	fs := flag.NewFlagSet("veil-verify", flag.ContinueOnError)
+	fs.SetOutput(out)
+
+	addr := fs.String(
+		"addr",
+		"",
+		"Address of the enclave, e.g.: https://example.com:8443",
+	)
+	testing := fs.Bool(
+		"insecure",
+		false,
+		"Enable testing by disabling attestation",
+	)
+
+	if err := fs.Parse(args); err != nil {
+		return nil, fmt.Errorf("failed to parse flags: %w", err)
+	}
+
+	return &config{
+		Addr:    *addr,
+		Testing: *testing,
+	}, nil
+}
+
+func run(ctx context.Context, out *os.File, args []string) error {
+	ctx, cancel := signal.NotifyContext(ctx, os.Interrupt)
+	defer cancel()
+
+	cfg, err := parseFlags(out, args)
+	if err != nil {
+		return err
+	}
+	if cfg.Addr == "" {
+		return fmt.Errorf("missing addr argument")
+	}
+
+	return attestEnclave(ctx, cfg)
+}
+
+func attestEnclave(ctx context.Context, cfg *config) (err error) {
+	defer errs.Wrap(&err, "failed to attest enclave")
+
+	nonce, err := nonce.New()
+	if err != nil {
+		return err
+	}
+
+	// Request the enclave's attestation document.  We don't care about HTTPS
+	// certificates because authentication is happening via the attestation
+	// document.
+	client := httputil.NewNoAuthHTTPClient()
+	url := cfg.Addr + "/enclave/attestation?nonce=" + nonce.URLEncode()
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("got status %d from enclave", resp.StatusCode)
+	}
+
+	// Parse the attestation document.
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	var doc enclave.AttestationDoc
+	if err := json.Unmarshal(body, &doc); err != nil {
+		return err
+	}
+
+	// Finally, verify the attestation document.
+	var attester enclave.Attester = enclave.NewNitroAttester()
+	if cfg.Testing {
+		attester = enclave.NewNoopAttester()
+	}
+	_, err = attester.Verify(&doc, nonce)
+	return err
+}
+
+func main() {
+	ctx := context.Background()
+	if err := run(ctx, os.Stdout, os.Args[1:]); err != nil {
+		log.Fatalf("Failed to run verifier: %v", err)
+	}
+	log.Println("Attestation successful")
+}