implement indeterminate LDAP verification (#1574)

This PR implements tri-state verification for the LDAP detector. This implementation looks for network errors to explicitly flag as indeterminate, rather than authentication errors to explicitly flag as determinate; this is because the error that occurs from authentication failures doesn't appear to have its own type and I didn't want to have to match on the error message text.

pkg/detectors/ldap/ldap.go

@@ -3,6 +3,8 @@ package ldap
 import (
 	"context"
 	"crypto/tls"
+	"fmt"
+	"net"
 	"net/url"
 	"regexp"
 	"strings"
@@ -63,7 +65,11 @@ func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (result
 				}
 
 				if verify {
-					s1.Verified = verifyLDAP(ctx, username[1], password[1], ldapURL)
+					verificationErr := verifyLDAP(username[1], password[1], ldapURL)
+					s1.Verified = verificationErr == nil
+					if !isErrDeterminate(verificationErr) {
+						s1.VerificationError = verificationErr
+					}
 				}
 
 				results = append(results, s1)
@@ -89,7 +95,12 @@ func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (result
 		}
 
 		if verify {
-			s1.Verified = verifyLDAP(ctx, username, password, ldapURL)
+			verificationError := verifyLDAP(username, password, ldapURL)
+
+			s1.Verified = verificationError == nil
+			if !isErrDeterminate(verificationError) {
+				s1.VerificationError = verificationError
+			}
 		}
 
 		results = append(results, s1)
@@ -98,7 +109,19 @@ func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (result
 	return results, nil
 }
 
-func verifyLDAP(ctx context.Context, username, password string, ldapURL *url.URL) bool {
+func isErrDeterminate(err error) bool {
+	switch e := err.(type) {
+	case *ldap.Error:
+		switch e.Err.(type) {
+		case *net.OpError:
+			return false
+		}
+	}
+
+	return true
+}
+
+func verifyLDAP(username, password string, ldapURL *url.URL) error {
 	// Tests with non-TLS, TLS, and STARTTLS
 
 	ldap.DefaultTimeout = 5 * time.Second
@@ -109,38 +132,35 @@ func verifyLDAP(ctx context.Context, username, password string, ldapURL *url.URL
 	case "ldap":
 		// Non-TLS dial
 		l, err := ldap.DialURL(uri)
+		if err != nil {
+			return err
+		}
+		defer l.Close()
+		// Non-TLS verify
+		err = l.Bind(username, password)
 		if err == nil {
-			defer l.Close()
-			// Non-TLS verify
-			err = l.Bind(username, password)
-			if err == nil {
-				return true
-			}
+			return nil
+		}
 
-			// STARTTLS
-			err = l.StartTLS(&tls.Config{InsecureSkipVerify: true})
-			if err == nil {
-				// STARTTLS verify
-				err = l.Bind(username, password)
-				if err == nil {
-					return true
-				}
-			}
+		// STARTTLS
+		err = l.StartTLS(&tls.Config{InsecureSkipVerify: true})
+		if err != nil {
+			return err
 		}
+		// STARTTLS verify
+		return l.Bind(username, password)
 	case "ldaps":
 		// TLS dial
 		l, err := ldap.DialTLS("tcp", uri, &tls.Config{InsecureSkipVerify: true})
-		if err == nil {
-			defer l.Close()
-			// TLS verify
-			err = l.Bind(username, password)
-			if err == nil {
-				return true
-			}
+		if err != nil {
+			return err
 		}
+		defer l.Close()
+		// TLS verify
+		return l.Bind(username, password)
 	}
 
-	return false
+	return fmt.Errorf("unknown ldap scheme %q", ldapURL.Scheme)
 }
 
 func (s Scanner) Type() detectorspb.DetectorType {

pkg/detectors/ldap/ldap_integration_test.go

@@ -7,13 +7,14 @@ import (
 	"bytes"
 	"context"
 	"errors"
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	"os"
 	"os/exec"
 	"strings"
 	"testing"
 	"time"
 
-	"github.com/kylelemons/godebug/pretty"
 	"github.com/trufflesecurity/trufflehog/v3/pkg/detectors"
 
 	"github.com/trufflesecurity/trufflehog/v3/pkg/pb/detectorspb"
@@ -60,11 +61,12 @@ func TestLdap_Integration_FromChunk(t *testing.T) {
 		verify bool
 	}
 	tests := []struct {
-		name    string
-		s       Scanner
-		args    args
-		want    []detectors.Result
-		wantErr bool
+		name                string
+		s                   Scanner
+		args                args
+		want                []detectors.Result
+		wantErr             bool
+		wantVerificationErr bool
 	}{
 		{
 			name: "found with URI and separate user+password usage, verified",
@@ -152,6 +154,26 @@ func TestLdap_Integration_FromChunk(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		{
+			name: "inaccessible host",
+			s:    Scanner{},
+			args: args{
+				ctx: context.Background(),
+				data: []byte(`
+		ldap://badhost:1389
+		binddn="cn=admin,dc=example,dc=org"
+		pass="P@55w0rd"`),
+				verify: true,
+			},
+			want: []detectors.Result{
+				{
+					DetectorType: detectorspb.DetectorType_LDAP,
+					Verified:     false,
+				},
+			},
+			wantErr:             false,
+			wantVerificationErr: true,
+		},
 		{
 			name: "not found",
 			s:    Scanner{},
@@ -176,9 +198,12 @@ func TestLdap_Integration_FromChunk(t *testing.T) {
 				if len(got[i].Raw) == 0 {
 					t.Fatalf("no raw secret present: \n %+v", got[i])
 				}
-				got[i].Raw = nil
+				if (got[i].VerificationError != nil) != tt.wantVerificationErr {
+					t.Fatalf("wantVerificationError = %v, verification error = %v", tt.wantVerificationErr, got[i].VerificationError)
+				}
 			}
-			if diff := pretty.Compare(got, tt.want); diff != "" {
+			ignoreOpts := cmpopts.IgnoreFields(detectors.Result{}, "Raw", "VerificationError")
+			if diff := cmp.Diff(got, tt.want, ignoreOpts); diff != "" {
 				t.Errorf("Ldap.FromData() %s diff: (-got +want)\n%s", tt.name, diff)
 			}
 		})
@@ -205,7 +230,7 @@ func startOpenLDAP() error {
 		return nil
 	case <-time.After(30 * time.Second):
 		stopOpenLDAP()
-		return errors.New("timeout waiting for postgres database to be ready")
+		return errors.New("timeout waiting for ldap service to be ready")
 	}
 }