feat: add --http-proxy flag for configurable HTTP CONNECT proxy

Add network.httpProxyUrl config field and --http-proxy CLI flag
(default: http://localhost:42051) for apps that only understand
HTTP proxies (opencode, Node.js tools, etc.).

macOS daemon mode now sets:
- ALL_PROXY=socks5h:// for SOCKS5-aware apps (curl, git)
- HTTP_PROXY/HTTPS_PROXY=http:// for HTTP-proxy-aware apps

Credentials from the SOCKS5 proxy URL are automatically injected
into the HTTP proxy URL when not explicitly configured.

cmd/greywall/main.go

@@ -31,6 +31,7 @@ var (
 	monitor       bool
 	settingsPath  string
 	proxyURL      string
+	httpProxyURL  string
 	dnsAddr       string
 	cmdString     string
 	exposePorts   []string
@@ -99,6 +100,7 @@ Configuration file format:
 	rootCmd.Flags().BoolVarP(&monitor, "monitor", "m", false, "Monitor and log sandbox violations")
 	rootCmd.Flags().StringVarP(&settingsPath, "settings", "s", "", "Path to settings file (default: OS config directory)")
 	rootCmd.Flags().StringVar(&proxyURL, "proxy", "", "External SOCKS5 proxy URL (default: socks5://localhost:42052)")
+	rootCmd.Flags().StringVar(&httpProxyURL, "http-proxy", "", "HTTP CONNECT proxy URL (default: http://localhost:42051)")
 	rootCmd.Flags().StringVar(&dnsAddr, "dns", "", "DNS server address on host (default: localhost:42053)")
 	rootCmd.Flags().StringVarP(&cmdString, "c", "c", "", "Run command string directly (like sh -c)")
 	rootCmd.Flags().StringArrayVarP(&exposePorts, "port", "p", nil, "Expose port for inbound connections (can be used multiple times)")
@@ -228,6 +230,9 @@ func runCommand(cmd *cobra.Command, args []string) error {
 	if proxyURL != "" {
 		cfg.Network.ProxyURL = proxyURL
 	}
+	if httpProxyURL != "" {
+		cfg.Network.HTTPProxyURL = httpProxyURL
+	}
 	if dnsAddr != "" {
 		cfg.Network.DnsAddr = dnsAddr
 	}
@@ -240,6 +245,12 @@ func runCommand(cmd *cobra.Command, args []string) error {
 			fmt.Fprintf(os.Stderr, "[greywall] Defaulting proxy to socks5://localhost:42052\n")
 		}
 	}
+	if cfg.Network.HTTPProxyURL == "" {
+		cfg.Network.HTTPProxyURL = "http://localhost:42051"
+		if debug {
+			fmt.Fprintf(os.Stderr, "[greywall] Defaulting HTTP proxy to http://localhost:42051\n")
+		}
+	}
 	if cfg.Network.DnsAddr == "" {
 		cfg.Network.DnsAddr = "localhost:42053"
 		if debug {

internal/config/config.go

@@ -27,6 +27,7 @@ type Config struct {
 // NetworkConfig defines network restrictions.
 type NetworkConfig struct {
 	ProxyURL            string   `json:"proxyUrl,omitempty"`     // External SOCKS5 proxy (e.g. socks5://host:1080)
+	HTTPProxyURL        string   `json:"httpProxyUrl,omitempty"` // HTTP CONNECT proxy (e.g. http://host:42051)
 	DnsAddr             string   `json:"dnsAddr,omitempty"`      // DNS server address on host (e.g. localhost:3153)
 	AllowUnixSockets    []string `json:"allowUnixSockets,omitempty"`
 	AllowAllUnixSockets bool     `json:"allowAllUnixSockets,omitempty"`
@@ -203,6 +204,11 @@ func (c *Config) Validate() error {
 			return fmt.Errorf("invalid network.proxyUrl %q: %w", c.Network.ProxyURL, err)
 		}
 	}
+	if c.Network.HTTPProxyURL != "" {
+		if err := validateHTTPProxyURL(c.Network.HTTPProxyURL); err != nil {
+			return fmt.Errorf("invalid network.httpProxyUrl %q: %w", c.Network.HTTPProxyURL, err)
+		}
+	}
 	if c.Network.DnsAddr != "" {
 		if err := validateHostPort(c.Network.DnsAddr); err != nil {
 			return fmt.Errorf("invalid network.dnsAddr %q: %w", c.Network.DnsAddr, err)
@@ -273,6 +279,24 @@ func validateProxyURL(proxyURL string) error {
 	return nil
 }
 
+// validateHTTPProxyURL validates an HTTP CONNECT proxy URL.
+func validateHTTPProxyURL(proxyURL string) error {
+	u, err := url.Parse(proxyURL)
+	if err != nil {
+		return fmt.Errorf("invalid URL: %w", err)
+	}
+	if u.Scheme != "http" && u.Scheme != "https" {
+		return errors.New("HTTP proxy URL must use http:// or https:// scheme")
+	}
+	if u.Hostname() == "" {
+		return errors.New("HTTP proxy URL must include a hostname")
+	}
+	if u.Port() == "" {
+		return errors.New("HTTP proxy URL must include a port")
+	}
+	return nil
+}
+
 // validateHostPort validates a host:port address.
 func validateHostPort(addr string) error {
 	// Must contain a colon separating host and port
@@ -407,8 +431,9 @@ func Merge(base, override *Config) *Config {
 		AllowPty: base.AllowPty || override.AllowPty,
 
 		Network: NetworkConfig{
-			// ProxyURL/DnsAddr: override wins if non-empty
+			// ProxyURL/HTTPProxyURL/DnsAddr: override wins if non-empty
 			ProxyURL:     mergeString(base.Network.ProxyURL, override.Network.ProxyURL),
+			HTTPProxyURL: mergeString(base.Network.HTTPProxyURL, override.Network.HTTPProxyURL),
 			DnsAddr:      mergeString(base.Network.DnsAddr, override.Network.DnsAddr),
 
 			// Append slices (base first, then override additions)

internal/sandbox/macos.go

@@ -763,28 +763,30 @@ func WrapCommandMacOS(cfg *config.Config, command string, exposedPorts []int, da
 		if socks5hURL != "" {
 			// ALL_PROXY uses socks5h:// (DNS resolved at proxy side) for
 			// SOCKS5-aware apps (curl, git).
-			// HTTP_PROXY/HTTPS_PROXY use http:// pointing to the GreyHaven
+			// HTTP_PROXY/HTTPS_PROXY use the configured HTTP CONNECT proxy
-			// HTTP CONNECT proxy (port 42051) for apps that only understand
+			// for apps that only understand HTTP proxies (opencode, Node.js
-			// HTTP proxies (opencode, Node.js tools, etc.). The CONNECT
+			// tools, etc.). The CONNECT proxy resolves DNS server-side.
-			// proxy resolves DNS server-side.
+			httpProxyURL := cfg.Network.HTTPProxyURL
-			httpProxyURL := "http://localhost:42051"
+			// Inject credentials from the SOCKS5 proxy URL into the HTTP proxy
-			if u, err := url.Parse(socks5hURL); err == nil {
+			// URL if the HTTP proxy URL doesn't already have credentials.
-				userinfo := ""
+			if httpProxyURL != "" {
-				if u.User != nil {
+				if hu, err := url.Parse(httpProxyURL); err == nil && hu.User == nil {
-					userinfo = u.User.String() + "@"
+					if su, err := url.Parse(socks5hURL); err == nil && su.User != nil {
+						hu.User = su.User
+						httpProxyURL = hu.String()
 					}
-				host := u.Hostname()
-				if host == "" {
-					host = "localhost"
 				}
-				httpProxyURL = "http://" + userinfo + host + ":42051"
 			}
 			sandboxEnvs = append(sandboxEnvs,
 				"ALL_PROXY="+socks5hURL, "all_proxy="+socks5hURL,
+			)
+			if httpProxyURL != "" {
+				sandboxEnvs = append(sandboxEnvs,
 					"HTTP_PROXY="+httpProxyURL, "http_proxy="+httpProxyURL,
 					"HTTPS_PROXY="+httpProxyURL, "https_proxy="+httpProxyURL,
 				)
 			}
+		}
 		termEnvs := getTerminalEnvVars()
 		parts = append(parts, "sudo", "-u", uid, "-g", daemonSession.SandboxGroup, "env")
 		parts = append(parts, sandboxEnvs...)