urlutil: add time validation functions

internal/urlutil/query_params.go

@@ -8,12 +8,16 @@ const (
 	QueryDeviceCredentialID = "pomerium_device_credential_id"
 	QueryDeviceType         = "pomerium_device_type"
 	QueryEnrollmentToken    = "pomerium_enrollment_token" //nolint
+	QueryExpiry             = "pomerium_expiry"
+	QueryIdentityProfile    = "pomerium_identity_profile"
 	QueryIdentityProviderID = "pomerium_idp_id"
 	QueryIsProgrammatic     = "pomerium_programmatic"
+	QueryIssued             = "pomerium_issued"
 	QueryPomeriumJWT        = "pomerium_jwt"
+	QueryRedirectURI        = "pomerium_redirect_uri"
 	QuerySession            = "pomerium_session"
 	QuerySessionEncrypted   = "pomerium_session_encrypted"
-	QueryRedirectURI        = "pomerium_redirect_uri"
+	QuerySessionState       = "pomerium_session_state"
 )
 
 // URL signature based query params used for verifying the authenticity of a URL.

internal/urlutil/time.go

@@ -0,0 +1,43 @@
+package urlutil
+
+import (
+	"fmt"
+	"net/url"
+	"strconv"
+	"time"
+)
+
+// BuildTimeParameters adds the issued and expiry timestamps to the query parameters.
+func BuildTimeParameters(params url.Values, expiry time.Duration) {
+	now := time.Now()
+
+	params.Set(QueryIssued, fmt.Sprint(now.UnixMilli()))
+	params.Set(QueryExpiry, fmt.Sprint(now.Add(expiry).UnixMilli()))
+}
+
+// ValidateTimeParameters validates that the issued and expiry timestamps in the query parameters are valid.
+func ValidateTimeParameters(params url.Values) error {
+	now := time.Now()
+
+	issuedMS, err := strconv.ParseInt(params.Get(QueryIssued), 10, 64)
+	if err != nil {
+		return fmt.Errorf("invalid issued timestamp: %w", err)
+	}
+	issued := time.UnixMilli(issuedMS)
+
+	if now.Add(DefaultLeeway).Before(issued) {
+		return ErrIssuedInTheFuture
+	}
+
+	expiryMS, err := strconv.ParseInt(params.Get(QueryExpiry), 10, 64)
+	if err != nil {
+		return fmt.Errorf("invalid expiry timestamp: %w", err)
+	}
+	expiry := time.UnixMilli(expiryMS)
+
+	if now.Add(-DefaultLeeway).After(expiry) {
+		return ErrExpired
+	}
+
+	return nil
+}

internal/urlutil/time_test.go

@@ -0,0 +1,63 @@
+package urlutil
+
+import (
+	"fmt"
+	"net/url"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuildTimeParameters(t *testing.T) {
+	t.Parallel()
+
+	params := make(url.Values)
+	BuildTimeParameters(params, time.Minute)
+	assert.True(t, params.Has(QueryIssued))
+	assert.True(t, params.Has(QueryExpiry))
+
+	ms1, _ := strconv.Atoi(params.Get(QueryIssued))
+	ms2, _ := strconv.Atoi(params.Get(QueryExpiry))
+	assert.Equal(t, 60000, ms2-ms1)
+}
+
+func TestValidateTimeParameters(t *testing.T) {
+	t.Parallel()
+
+	msNow := time.Now().UnixMilli()
+	for _, tc := range []struct {
+		name   string
+		params url.Values
+		err    string
+	}{
+		{"empty", url.Values{}, "invalid issued timestamp"},
+		{"missing issued", url.Values{QueryExpiry: {fmt.Sprint(msNow + 10000)}}, "invalid issued timestamp"},
+		{"missing expiry", url.Values{QueryIssued: {fmt.Sprint(msNow + 10000)}}, "invalid expiry timestamp"},
+		{"invalid issued", url.Values{
+			QueryIssued: {fmt.Sprint(msNow + 120000)},
+			QueryExpiry: {fmt.Sprint(msNow + 240000)},
+		}, "issued in the future"},
+		{"invalid expiry", url.Values{
+			QueryIssued: {fmt.Sprint(msNow - 120000)},
+			QueryExpiry: {fmt.Sprint(msNow - 240000)},
+		}, "expired"},
+		{"valid", url.Values{
+			QueryIssued: {fmt.Sprint(msNow)},
+			QueryExpiry: {fmt.Sprint(msNow)},
+		}, ""},
+	} {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			err := ValidateTimeParameters(tc.params)
+			if tc.err == "" {
+				assert.NoError(t, err)
+			} else {
+				assert.ErrorContains(t, err, tc.err)
+			}
+		})
+	}
+}