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tailscale/ipn/serve.go

259 lines
7.6 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package ipn
import (
"errors"
"fmt"
"net"
"net/netip"
"net/url"
"strconv"
"strings"
"golang.org/x/exp/slices"
"tailscale.com/tailcfg"
)
// ServeConfigKey returns a StateKey that stores the
// JSON-encoded ServeConfig for a config profile.
func ServeConfigKey(profileID ProfileID) StateKey {
return StateKey("_serve/" + profileID)
}
// ServeConfig is the JSON type stored in the StateStore for
// StateKey "_serve/$PROFILE_ID" as returned by ServeConfigKey.
type ServeConfig struct {
// TCP are the list of TCP port numbers that tailscaled should handle for
// the Tailscale IP addresses. (not subnet routers, etc)
TCP map[uint16]*TCPPortHandler `json:",omitempty"`
// Web maps from "$SNI_NAME:$PORT" to a set of HTTP handlers
// keyed by mount point ("/", "/foo", etc)
Web map[HostPort]*WebServerConfig `json:",omitempty"`
// AllowFunnel is the set of SNI:port values for which funnel
// traffic is allowed, from trusted ingress peers.
AllowFunnel map[HostPort]bool `json:",omitempty"`
}
// HostPort is an SNI name and port number, joined by a colon.
// There is no implicit port 443. It must contain a colon.
type HostPort string
// A FunnelConn wraps a net.Conn that is coming over a
// Funnel connection. It can be used to determine further
// information about the connection, like the source address
// and the target SNI name.
type FunnelConn struct {
// Conn is the underlying connection.
net.Conn
// Target is what was presented in the "Tailscale-Ingress-Target"
// HTTP header.
Target HostPort
// Src is the source address of the connection.
// This is the address of the client that initiated the
// connection, not the address of the Tailscale Funnel
// node which is relaying the connection. That address
// can be found in Conn.RemoteAddr.
Src netip.AddrPort
}
// WebServerConfig describes a web server's configuration.
type WebServerConfig struct {
Handlers map[string]*HTTPHandler // mountPoint => handler
}
// TCPPortHandler describes what to do when handling a TCP
// connection.
type TCPPortHandler struct {
// HTTPS, if true, means that tailscaled should handle this connection as an
// HTTPS request as configured by ServeConfig.Web.
//
// It is mutually exclusive with TCPForward.
HTTPS bool `json:",omitempty"`
// TCPForward is the IP:port to forward TCP connections to.
// Whether or not TLS is terminated by tailscaled depends on
// TerminateTLS.
//
// It is mutually exclusive with HTTPS.
TCPForward string `json:",omitempty"`
// TerminateTLS, if non-empty, means that tailscaled should terminate the
// TLS connections before forwarding them to TCPForward, permitting only the
// SNI name with this value. It is only used if TCPForward is non-empty.
// (the HTTPS mode uses ServeConfig.Web)
TerminateTLS string `json:",omitempty"`
}
// HTTPHandler is either a path or a proxy to serve.
type HTTPHandler struct {
// Exactly one of the following may be set.
Path string `json:",omitempty"` // absolute path to directory or file to serve
Proxy string `json:",omitempty"` // http://localhost:3000/, localhost:3030, 3030
Text string `json:",omitempty"` // plaintext to serve (primarily for testing)
// TODO(bradfitz): bool to not enumerate directories? TTL on mapping for
// temporary ones? Error codes? Redirects?
}
// WebHandlerExists checks if the ServeConfig Web handler exists for
// the given host:port and mount point.
func (sc *ServeConfig) WebHandlerExists(hp HostPort, mount string) bool {
h := sc.GetWebHandler(hp, mount)
return h != nil
}
// GetWebHandler returns the HTTPHandler for the given host:port and mount point.
// Returns nil if the handler does not exist.
func (sc *ServeConfig) GetWebHandler(hp HostPort, mount string) *HTTPHandler {
if sc == nil || sc.Web[hp] == nil {
return nil
}
return sc.Web[hp].Handlers[mount]
}
// GetTCPPortHandler returns the TCPPortHandler for the given port.
// If the port is not configured, nil is returned.
func (sc *ServeConfig) GetTCPPortHandler(port uint16) *TCPPortHandler {
if sc == nil {
return nil
}
return sc.TCP[port]
}
// IsTCPForwardingAny checks if ServeConfig is currently forwarding
// in TCPForward mode on any port.
// This is exclusive of Web/HTTPS serving.
func (sc *ServeConfig) IsTCPForwardingAny() bool {
if sc == nil || len(sc.TCP) == 0 {
return false
}
for _, h := range sc.TCP {
if h.TCPForward != "" {
return true
}
}
return false
}
// IsTCPForwardingOnPort checks if ServeConfig is currently forwarding
// in TCPForward mode on the given port.
// This is exclusive of Web/HTTPS serving.
func (sc *ServeConfig) IsTCPForwardingOnPort(port uint16) bool {
if sc == nil || sc.TCP[port] == nil {
return false
}
return !sc.TCP[port].HTTPS
}
// IsServingWeb checks if ServeConfig is currently serving
// Web/HTTPS on the given port.
// This is exclusive of TCPForwarding.
func (sc *ServeConfig) IsServingWeb(port uint16) bool {
if sc == nil || sc.TCP[port] == nil {
return false
}
return sc.TCP[port].HTTPS
}
// IsFunnelOn checks if ServeConfig is currently allowing
// funnel traffic for any host:port.
func (sc *ServeConfig) IsFunnelOn() bool {
if sc == nil {
return false
}
for _, b := range sc.AllowFunnel {
if b {
return true
}
}
return false
}
// CheckFunnelAccess checks whether Funnel access is allowed for the given node
// and port.
// It checks:
// 1. Funnel is enabled on the Tailnet
// 2. HTTPS is enabled on the Tailnet
// 3. the node has the "funnel" nodeAttr
// 4. the port is allowed for Funnel
//
// The nodeAttrs arg should be the node's Self.Capabilities which should contain
// the attribute we're checking for and possibly warning-capabilities for
// Funnel.
func CheckFunnelAccess(port uint16, nodeAttrs []string) error {
if slices.Contains(nodeAttrs, tailcfg.CapabilityWarnFunnelNoInvite) {
return errors.New("Funnel not enabled; See https://tailscale.com/s/no-funnel.")
}
if slices.Contains(nodeAttrs, tailcfg.CapabilityWarnFunnelNoHTTPS) {
return errors.New("Funnel not available; HTTPS must be enabled. See https://tailscale.com/s/https.")
}
if !slices.Contains(nodeAttrs, tailcfg.NodeAttrFunnel) {
return errors.New("Funnel not available; \"funnel\" node attribute not set. See https://tailscale.com/s/no-funnel.")
}
return checkFunnelPort(port, nodeAttrs)
}
// checkFunnelPort checks whether the given port is allowed for Funnel.
// It uses the tailcfg.CapabilityFunnelPorts nodeAttr to determine the allowed
// ports.
func checkFunnelPort(wantedPort uint16, nodeAttrs []string) error {
deny := func(allowedPorts string) error {
if allowedPorts == "" {
return fmt.Errorf("port %d is not allowed for funnel", wantedPort)
}
return fmt.Errorf("port %d is not allowed for funnel; allowed ports are: %v", wantedPort, allowedPorts)
}
var portsStr string
for _, attr := range nodeAttrs {
if !strings.HasPrefix(attr, tailcfg.CapabilityFunnelPorts) {
continue
}
u, err := url.Parse(attr)
if err != nil {
return deny("")
}
portsStr = u.Query().Get("ports")
if portsStr == "" {
return deny("")
}
u.RawQuery = ""
if u.String() != tailcfg.CapabilityFunnelPorts {
return deny("")
}
}
wantedPortString := strconv.Itoa(int(wantedPort))
for _, ps := range strings.Split(portsStr, ",") {
if ps == "" {
continue
}
first, last, ok := strings.Cut(ps, "-")
if !ok {
if first == wantedPortString {
return nil
}
continue
}
fp, err := strconv.ParseUint(first, 10, 16)
if err != nil {
continue
}
lp, err := strconv.ParseUint(last, 10, 16)
if err != nil {
continue
}
pr := tailcfg.PortRange{First: uint16(fp), Last: uint16(lp)}
if pr.Contains(wantedPort) {
return nil
}
}
return deny(portsStr)
}