From b9d73497efe7c28800040b3e421bfb4cb6af6092 Mon Sep 17 00:00:00 2001 From: Claude Date: Tue, 26 May 2026 21:08:25 +0000 Subject: feat(config,cli): loopback-default binding with fail-loud on external (Phase 7) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The server now defaults to binding 127.0.0.1 and refuses to bind a non-loopback address (:8484, 0.0.0.0, a LAN IP, …) unless external_bind_allowed = true is set in config — failing loud at startup instead of silently exposing itself. External access is expected to go through a reverse proxy (Tailscale / Cloudflare Access / Caddy), per the locked auth model. - config: ExternalBindAllowed flag + ValidateBindAddr/isLoopbackHost (tested across loopback, all-interfaces, LAN, and override cases). - cli: --addr default is now 127.0.0.1:8484; serve() validates before binding. Per-client bearer rotation stays deferred (single shared token for now). https://claude.ai/code/session_01SESwn7kQ7oP62trWw6pc39 --- internal/cli/serve.go | 6 +++++- internal/config/bind.go | 44 ++++++++++++++++++++++++++++++++++++++++++++ internal/config/bind_test.go | 27 +++++++++++++++++++++++++++ internal/config/config.go | 6 +++++- 4 files changed, 81 insertions(+), 2 deletions(-) create mode 100644 internal/config/bind.go create mode 100644 internal/config/bind_test.go (limited to 'internal') diff --git a/internal/cli/serve.go b/internal/cli/serve.go index 7afa678..9aa765b 100644 --- a/internal/cli/serve.go +++ b/internal/cli/serve.go @@ -12,6 +12,7 @@ import ( "github.com/thepeterstone/claudomator/internal/api" "github.com/thepeterstone/claudomator/internal/budget" + "github.com/thepeterstone/claudomator/internal/config" "github.com/thepeterstone/claudomator/internal/executor" "github.com/thepeterstone/claudomator/internal/notify" "github.com/thepeterstone/claudomator/internal/storage" @@ -34,7 +35,7 @@ func newServeCmd() *cobra.Command { }, } - cmd.Flags().StringVar(&addr, "addr", ":8484", "listen address") + cmd.Flags().StringVar(&addr, "addr", "127.0.0.1:8484", "listen address (loopback by default; set external_bind_allowed=true in config to bind externally)") cmd.Flags().StringVar(&workspaceRoot, "workspace-root", "/workspace", "root directory for listing workspaces") cmd.Flags().StringVar(&cfg.ClaudeImage, "claude-image", cfg.ClaudeImage, "docker image for claude agents") cmd.Flags().StringVar(&cfg.GeminiImage, "gemini-image", cfg.GeminiImage, "docker image for gemini agents") @@ -43,6 +44,9 @@ func newServeCmd() *cobra.Command { } func serve(addr string) error { + if err := config.ValidateBindAddr(addr, cfg.ExternalBindAllowed); err != nil { + return err + } if err := cfg.EnsureDirs(); err != nil { return fmt.Errorf("creating dirs: %w", err) } diff --git a/internal/config/bind.go b/internal/config/bind.go new file mode 100644 index 0000000..f117385 --- /dev/null +++ b/internal/config/bind.go @@ -0,0 +1,44 @@ +package config + +import ( + "fmt" + "net" +) + +// ValidateBindAddr enforces loopback-by-default binding. It returns an error +// when addr resolves to a non-loopback interface and externalAllowed is false, +// so the server fails loud rather than silently exposing itself. Loopback +// addresses (127.0.0.1, ::1, localhost) always pass. +func ValidateBindAddr(addr string, externalAllowed bool) error { + host, _, err := net.SplitHostPort(addr) + if err != nil { + // No port (or malformed): treat the whole string as the host. + host = addr + } + if isLoopbackHost(host) { + return nil + } + if externalAllowed { + return nil + } + return fmt.Errorf( + "refusing to bind non-loopback address %q: set external_bind_allowed = true to override, "+ + "but prefer fronting external access with a reverse proxy (Tailscale / Cloudflare Access / Caddy)", + addr, + ) +} + +// isLoopbackHost reports whether host is a loopback target. An empty host +// (e.g. ":8484") or 0.0.0.0/:: binds all interfaces and is NOT loopback. +func isLoopbackHost(host string) bool { + switch host { + case "localhost": + return true + case "": + return false + } + if ip := net.ParseIP(host); ip != nil { + return ip.IsLoopback() + } + return false +} diff --git a/internal/config/bind_test.go b/internal/config/bind_test.go new file mode 100644 index 0000000..8e0ab4b --- /dev/null +++ b/internal/config/bind_test.go @@ -0,0 +1,27 @@ +package config + +import "testing" + +func TestValidateBindAddr(t *testing.T) { + cases := []struct { + addr string + external bool + wantErr bool + }{ + {"127.0.0.1:8484", false, false}, // loopback ok + {"localhost:8484", false, false}, // loopback ok + {"[::1]:8484", false, false}, // ipv6 loopback ok + {":8484", false, true}, // all interfaces, not allowed + {"0.0.0.0:8484", false, true}, // all interfaces, not allowed + {"192.168.1.10:8484", false, true}, // LAN ip, not allowed + {":8484", true, false}, // all interfaces, explicitly allowed + {"0.0.0.0:8484", true, false}, // explicitly allowed + {"192.168.1.10:8484", true, false}, // explicitly allowed + } + for _, c := range cases { + err := ValidateBindAddr(c.addr, c.external) + if (err != nil) != c.wantErr { + t.Errorf("ValidateBindAddr(%q, external=%v): err=%v, wantErr=%v", c.addr, c.external, err, c.wantErr) + } + } +} diff --git a/internal/config/config.go b/internal/config/config.go index 58de95c..6f6b958 100644 --- a/internal/config/config.go +++ b/internal/config/config.go @@ -70,6 +70,10 @@ type Config struct { ClaudeConfigDir string `toml:"claude_config_dir"` LocalModel LocalModel `toml:"local_model"` Budget BudgetConfig `toml:"budget"` + // ExternalBindAllowed must be explicitly true to bind a non-loopback address. + // Default external access should go through a reverse proxy (Tailscale / + // Cloudflare Access / Caddy); binding the server directly is a footgun. + ExternalBindAllowed bool `toml:"external_bind_allowed"` } // BudgetConfig configures rolling per-provider spend caps. With no providers @@ -103,7 +107,7 @@ func Default() (*Config, error) { GeminiImage: "claudomator-agent:latest", MaxConcurrent: 3, DefaultTimeout: "15m", - ServerAddr: ":8484", + ServerAddr: "127.0.0.1:8484", WorkspaceRoot: "/workspace", ClaudeConfigDir: "/workspace/claudomator/credentials/claude", }, nil -- cgit v1.2.3