Authorize daemon IPC callers by their local identity

client/cmd/daemon_error.go

@@ -0,0 +1,66 @@
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	gstatus "google.golang.org/grpc/status"
+
+	"github.com/netbirdio/netbird/client/internal/ipcauth"
+)
+
+// daemonCallError prepares a daemon error for display. A refusal the daemon
+// raised because the operation needs root/administrator is already guidance
+// written for the user, so it is surfaced on its own instead of buried under the
+// gRPC envelope and the name of the RPC that hit it. Anything else is wrapped
+// with context as usual.
+func daemonCallError(context string, err error) error {
+	if guidance, ok := privilegeGuidance(err); ok {
+		return errors.New(guidance)
+	}
+	return fmt.Errorf("%s: %w", context, err)
+}
+
+// privilegeGuidance renders the daemon's privilege refusal as a summary and the
+// command that performs the operation with the privileges it needs. It reports
+// false for any other error.
+func privilegeGuidance(err error) (string, bool) {
+	info, ok := privilegeErrorInfo(err)
+	if !ok {
+		return "", false
+	}
+
+	summary := info.GetMetadata()[ipcauth.ErrorMetaSummary]
+	command := info.GetMetadata()[ipcauth.ErrorMetaCommand]
+	if summary == "" {
+		// Detail without a summary: fall back to the status message, which
+		// carries the same text.
+		summary = strings.TrimSpace(gstatus.Convert(err).Message())
+	}
+	if command == "" {
+		return summary, true
+	}
+
+	return fmt.Sprintf("%s\n\n    %s\n", summary, command), true
+}
+
+// privilegeErrorInfo returns the daemon's privilege-refusal detail, if the error
+// carries one.
+func privilegeErrorInfo(err error) (*errdetails.ErrorInfo, bool) {
+	if err == nil {
+		return nil, false
+	}
+
+	for _, detail := range gstatus.Convert(err).Details() {
+		info, ok := detail.(*errdetails.ErrorInfo)
+		if !ok {
+			continue
+		}
+		if info.GetReason() == ipcauth.ErrorReasonPrivilegeRequired && info.GetDomain() == ipcauth.ErrorDomain {
+			return info, true
+		}
+	}
+	return nil, false
+}