WIP

cmd/veil-verify/main.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
 
 	"github.com/Amnesic-Systems/veil/internal/enclave"
 	"github.com/Amnesic-Systems/veil/internal/enclave/nitro"
@@ -22,6 +23,7 @@ import (
 type config struct {
 	Addr    string
 	Testing bool
+	PCRs    enclave.PCR
 }
 
 func parseFlags(out io.Writer, args []string) (*config, error) {
@@ -33,6 +35,11 @@ func parseFlags(out io.Writer, args []string) (*config, error) {
 		"",
 		"Address of the enclave, e.g.: https://example.com:8443",
 	)
+	msmts := fs.String(
+		"measurements",
+		"",
+		"JSON-encoded enclave image measurements",
+	)
 	testing := fs.Bool(
 		"insecure",
 		false,
@@ -43,9 +50,53 @@ func parseFlags(out io.Writer, args []string) (*config, error) {
 		return nil, fmt.Errorf("failed to parse flags: %w", err)
 	}
 
+	pcr, err := toPCR([]byte(*msmts))
+	if err != nil {
+		return nil, err
+	}
+
 	return &config{
 		Addr:    *addr,
 		Testing: *testing,
+		PCRs:    pcr,
+	}, nil
+}
+
+func toPCR(jsonMsmts []byte) (enclave.PCR, error) {
+	// This structs represents the JSON-encoded measurements of the enclave image.
+	// The JSON tags must match the output of the nitro-cli command line tool. An
+	// example:
+	//
+	//	{
+	//	  "Measurements": {
+	//	    "HashAlgorithm": "Sha384 { ... }",
+	//	    "PCR0": "8b927cf0bbf2d668a8c24c69afd23bff2dda713b4f0d70195205950f9a5a1fbb7089ad937e3025ee8d5a084f3d6c9126",
+	//	    "PCR1": "4b4d5b3661b3efc12920900c80e126e4ce783c522de6c02a2a5bf7af3a2b9327b86776f188e4be1c1c404a129dbda493",
+	//	    "PCR2": "22d2194eb27a7cda42e66dd5b91ef13e5a153d797c04ae179e59bef1c93438d6ad0365c175c119230e36d0f8d6b6b59e"
+	//	  }
+	//	}
+	m := struct {
+		Measurements struct {
+			HashAlgorithm string `json:"HashAlgorithm"`
+			PCR0          string `json:"PCR0"`
+			PCR1          string `json:"PCR1"`
+			PCR2          string `json:"PCR2"`
+		} `json:"Measurements"`
+	}{}
+	if err := json.Unmarshal(jsonMsmts, &m); err != nil {
+		return nil, err
+	}
+
+	const want = "sha384"
+	got := strings.ToLower(m.Measurements.HashAlgorithm)
+	if !strings.HasPrefix(got, want) {
+		return nil, fmt.Errorf("expected hash algorithm %q but got %q", want, got)
+	}
+
+	return enclave.PCR{
+		0: []byte(m.Measurements.PCR0),
+		1: []byte(m.Measurements.PCR1),
+		2: []byte(m.Measurements.PCR2),
 	}, nil
 }
 
@@ -95,8 +146,8 @@ func attestEnclave(ctx context.Context, cfg *config) (err error) {
 		return err
 	}
 	defer resp.Body.Close()
-	var doc enclave.RawDocument
-	if err := json.Unmarshal(body, &doc); err != nil {
+	var rawDoc enclave.RawDocument
+	if err := json.Unmarshal(body, &rawDoc); err != nil {
 		return err
 	}
 
@@ -105,7 +156,12 @@ func attestEnclave(ctx context.Context, cfg *config) (err error) {
 	if cfg.Testing {
 		attester = noop.NewAttester()
 	}
-	_, err = attester.Verify(&doc, nonce)
+	doc, err := attester.Verify(&rawDoc, nonce)
+
+	if !cfg.PCRs.Equal(doc.PCRs) {
+		fmt.Println("NOT EQUAL")
+	}
+
 	return err
 }
 

internal/enclave/attester.go

@@ -25,7 +25,7 @@ type Document struct {
 	ModuleID    string   `cbor:"module_id" json:"module_id"`
 	Timestamp   uint64   `cbor:"timestamp" json:"timestamp"`
 	Digest      string   `cbor:"digest" json:"digest"`
-	PCRs        pcr      `cbor:"pcrs" json:"pcrs"`
+	PCRs        PCR      `cbor:"pcrs" json:"pcrs"`
 	Certificate []byte   `cbor:"certificate" json:"certificate"`
 	CABundle    [][]byte `cbor:"cabundle" json:"cabundle"`
 	AuxInfo

internal/enclave/pcr.go

@@ -7,12 +7,12 @@ import (
 
 var emptyPCR = make([]byte, sha512.Size384)
 
-// pcr represents the enclave's platform configuration register (PCR) values.
-type pcr map[uint][]byte
+// PCR represents the enclave's platform configuration register (PCR) values.
+type PCR map[uint][]byte
 
 // FromDebugMode returns true if the given PCR map was generated by an enclave
 // in debug mode.
-func (p pcr) FromDebugMode() bool {
+func (p PCR) FromDebugMode() bool {
 	// PCRs 0, 1, and 2 are set at compile time but will be unset if the enclave
 	// is running in debug mode.
 	return bytes.Equal(p[0], emptyPCR) &&
@@ -21,7 +21,7 @@ func (p pcr) FromDebugMode() bool {
 }
 
 // Equal returns true if (and only if) the two given PCR maps are identical.
-func (ours pcr) Equal(theirs pcr) bool {
+func (ours PCR) Equal(theirs PCR) bool {
 	if len(ours) != len(theirs) {
 		return false
 	}

internal/enclave/pcr_test.go

@@ -10,16 +10,16 @@ import (
 func TestPCRsFromDebugMode(t *testing.T) {
 	cases := []struct {
 		name string
-		pcrs pcr
+		pcrs PCR
 		want bool
 	}{
 		{
 			name: "empty",
-			pcrs: pcr{},
+			pcrs: PCR{},
 		},
 		{
 			name: "debug mode",
-			pcrs: pcr{
+			pcrs: PCR{
 				0: emptyPCR,
 				1: emptyPCR,
 				2: emptyPCR,
@@ -30,7 +30,7 @@ func TestPCRsFromDebugMode(t *testing.T) {
 		},
 		{
 			name: "not debug mode",
-			pcrs: pcr{
+			pcrs: PCR{
 				0: []byte("foo"),
 				1: emptyPCR,
 				2: emptyPCR,
@@ -48,65 +48,65 @@ func TestPCRsFromDebugMode(t *testing.T) {
 func TestPCRsEqual(t *testing.T) {
 	cases := []struct {
 		name string
-		pcr1 pcr
-		pcr2 pcr
+		pcr1 PCR
+		pcr2 PCR
 		want bool
 	}{
 		{
 			name: "empty",
-			pcr1: pcr{},
-			pcr2: pcr{},
+			pcr1: PCR{},
+			pcr2: PCR{},
 			want: true,
 		},
 		{
 			name: "identical",
-			pcr1: pcr{
+			pcr1: PCR{
 				1: []byte("foobar"),
 			},
-			pcr2: pcr{
+			pcr2: PCR{
 				1: []byte("foobar"),
 			},
 			want: true,
 		},
 		{
 			name: "PCR mismatch",
-			pcr1: pcr{
+			pcr1: PCR{
 				1: []byte("foobar"),
 			},
-			pcr2: pcr{
+			pcr2: PCR{
 				1: []byte("barfoo"),
 			},
 			want: false,
 		},
 		{
 			name: "ignore PCR4",
-			pcr1: pcr{
+			pcr1: PCR{
 				1: []byte("foobar"),
 				4: []byte("foo"),
 			},
-			pcr2: pcr{
+			pcr2: PCR{
 				1: []byte("foobar"),
 				4: []byte("bar"),
 			},
 			want: true,
 		},
 		{
 			name: "length mismatch",
-			pcr1: pcr{
+			pcr1: PCR{
 				1: []byte("foobar"),
 				2: []byte("foo"),
 			},
-			pcr2: pcr{
+			pcr2: PCR{
 				1: []byte("foobar"),
 			},
 			want: false,
 		},
 		{
 			name: "PCR index mismatch",
-			pcr1: pcr{
+			pcr1: PCR{
 				1: []byte("foo"),
 			},
-			pcr2: pcr{
+			pcr2: PCR{
 				2: []byte("foo"),
 			},
 			want: false,