keytab test and fix minor bug

keytab/keytab.go

@@ -107,7 +107,6 @@ func Parse(b []byte) (kt Keytab, err error) {
 	*/
 	// n tracks position in the byte array
 	n := 2
-	//Version 2 so Big Endian
 	l := read_int32(b, &n, &endian)
 	for l != 0 {
 		if l < 0 {
@@ -142,6 +141,10 @@ func Parse(b []byte) (kt Keytab, err error) {
 			// Add the entry to the keytab
 			kt.Entries = append(kt.Entries, ke)
 		}
+		// Check if there are still 4 bytes left to read
+		if len(b[n:]) < 4 {
+			break
+		}
 		// Read the size of the next entry
 		l = read_int32(b, &n, &endian)
 	}

keytab/keytab_test.go

@@ -0,0 +1,29 @@
+package keytab
+
+import (
+	"encoding/hex"
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"time"
+)
+
+//Keytab data generated from ktutil
+const keytabDataHexStr = "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"
+
+func TestParse(t *testing.T) {
+	dat, _ := hex.DecodeString(keytabDataHexStr)
+	kt, err := Parse(dat)
+	if err != nil {
+		t.Fatalf("Error parsing keytab data: %v\n", err)
+	}
+	assert.Equal(t, uint16(2), kt.Version, "Keytab version not as expected")
+	assert.Equal(t, uint32(1), kt.Entries[0].KVNO, "KVNO not as expected")
+	assert.Equal(t, uint8(1), kt.Entries[0].KVNO8, "KVNO8 not as expected")
+	assert.Equal(t, time.Unix(1483384877, 0), kt.Entries[0].Timestamp, "Timestamp not as expected")
+	assert.Equal(t, uint16(23), kt.Entries[0].Key.EType, "Key's EType not as expected")
+	assert.Equal(t, "0c61039f010b2fbb88fe449fbf262477", hex.EncodeToString(kt.Entries[0].Key.KeyMaterial), "Timestamp not as expected")
+	assert.Equal(t, int16(1), kt.Entries[0].Principal.NumComponents, "Number of components in principal not as expected")
+	assert.Equal(t, int32(1), kt.Entries[0].Principal.NameType, "Number of components in principal not as expected")
+	assert.Equal(t, "EXAMPLE.COM", kt.Entries[0].Principal.Realm, "Number of components in principal not as expected")
+	assert.Equal(t, "user", kt.Entries[0].Principal.Components[0], "Number of components in principal not as expected")
+}