cryptutil: move to pkg dir, add token generator (#1029)

* cryptutil: move to pkg dir, add token generator

* add gitignored files

* add tests

pkg/cryptutil/hmac_test.go

@@ -0,0 +1,70 @@
+package cryptutil
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestHMAC(t *testing.T) {
+	// https://groups.google.com/d/msg/sci.crypt/OolWgsgQD-8/jHciyWkaL0gJ
+	hmacTests := []struct {
+		key    string
+		data   string
+		digest string
+	}{
+		{
+			key:    "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
+			data:   "4869205468657265", // "Hi There"
+			digest: "9f9126c3d9c3c330d760425ca8a217e31feae31bfe70196ff81642b868402eab",
+		},
+		{
+			key:    "4a656665",                                                 // "Jefe"
+			data:   "7768617420646f2079612077616e7420666f72206e6f7468696e673f", // "what do ya want for nothing?"
+			digest: "6df7b24630d5ccb2ee335407081a87188c221489768fa2020513b2d593359456",
+		},
+	}
+	for idx, tt := range hmacTests {
+		keySlice, _ := hex.DecodeString(tt.key)
+		dataBytes, _ := hex.DecodeString(tt.data)
+		expectedDigest, _ := hex.DecodeString(tt.digest)
+
+		keyBytes := &[32]byte{}
+		copy(keyBytes[:], keySlice)
+
+		macDigest := GenerateHMAC(dataBytes, string(keyBytes[:]))
+		if !bytes.Equal(macDigest, expectedDigest) {
+			t.Errorf("test %d generated unexpected mac", idx)
+		}
+		if !CheckHMAC(dataBytes, macDigest, string(keyBytes[:])) {
+			t.Errorf("test %d generated unexpected mac", idx)
+		}
+	}
+}
+
+func TestValidTimestamp(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name    string
+		ts      string
+		wantErr bool
+	}{
+		{"good - now", fmt.Sprint(time.Now().Unix()), false},
+		{"good - now - 200ms", fmt.Sprint(time.Now().Add(-200 * time.Millisecond).Unix()), false},
+		{"good - now + 200ms", fmt.Sprint(time.Now().Add(200 * time.Millisecond).Unix()), false},
+		{"bad - now + 10m", fmt.Sprint(time.Now().Add(10 * time.Minute).Unix()), true},
+		{"bad - now - 10m", fmt.Sprint(time.Now().Add(-10 * time.Minute).Unix()), true},
+		{"malformed - non int", fmt.Sprint("pomerium"), true},
+		{"malformed - negative number", fmt.Sprint("-1"), true},
+		{"malformed - huge number", fmt.Sprintf("%d", 10*10000000000), true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := ValidTimestamp(tt.ts); (err != nil) != tt.wantErr {
+				t.Errorf("ValidTimestamp() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}