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tailscale/ipn/prefs.go

643 lines
19 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ipn
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"log"
"os"
"path/filepath"
"reflect"
"runtime"
"strings"
"inet.af/netaddr"
"tailscale.com/atomicfile"
"tailscale.com/ipn/ipnstate"
"tailscale.com/net/tsaddr"
"tailscale.com/tailcfg"
"tailscale.com/types/persist"
"tailscale.com/types/preftype"
"tailscale.com/util/dnsname"
)
//go:generate go run tailscale.com/cmd/cloner -type=Prefs
// DefaultControlURL is the URL base of the control plane
// ("coordination server") for use when no explicit one is configured.
// The default control plane is the hosted version run by Tailscale.com.
const DefaultControlURL = "https://controlplane.tailscale.com"
var (
// ErrExitNodeIDAlreadySet is returned from (*Prefs).SetExitNodeIP when the
// Prefs.ExitNodeID field is already set.
ErrExitNodeIDAlreadySet = errors.New("cannot set ExitNodeIP when ExitNodeID is already set")
)
// IsLoginServerSynonym reports whether a URL is a drop-in replacement
// for the primary Tailscale login server.
func IsLoginServerSynonym(val any) bool {
return val == "https://login.tailscale.com" || val == "https://controlplane.tailscale.com"
}
// Prefs are the user modifiable settings of the Tailscale node agent.
type Prefs struct {
// ControlURL is the URL of the control server to use.
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
//
// If empty, the default for new installs, DefaultControlURL
// is used. It's set non-empty once the daemon has been started
// for the first time.
//
// TODO(apenwarr): Make it safe to update this with SetPrefs().
// Right now, you have to pass it in the initial prefs in Start(),
// which is the only code that actually uses the ControlURL value.
// It would be more consistent to restart controlclient
// automatically whenever this variable changes.
//
// Meanwhile, you have to provide this as part of Options.Prefs or
// Options.UpdatePrefs when calling Backend.Start().
ControlURL string
// RouteAll specifies whether to accept subnets advertised by
// other nodes on the Tailscale network. Note that this does not
// include default routes (0.0.0.0/0 and ::/0), those are
// controlled by ExitNodeID/IP below.
RouteAll bool
// AllowSingleHosts specifies whether to install routes for each
// node IP on the tailscale network, in addition to a route for
// the whole network.
// This corresponds to the "tailscale up --host-routes" value,
// which defaults to true.
//
// TODO(danderson): why do we have this? It dumps a lot of stuff
// into the routing table, and a single network route _should_ be
// all that we need. But when I turn this off in my tailscaled,
// packets stop flowing. What's up with that?
AllowSingleHosts bool
// ExitNodeID and ExitNodeIP specify the node that should be used
// as an exit node for internet traffic. At most one of these
// should be non-zero.
//
// The preferred way to express the chosen node is ExitNodeID, but
// in some cases it's not possible to use that ID (e.g. in the
// linux CLI, before tailscaled has a netmap). For those
// situations, we allow specifying the exit node by IP, and
// ipnlocal.LocalBackend will translate the IP into an ID when the
// node is found in the netmap.
//
// If the selected exit node doesn't exist (e.g. it's not part of
// the current tailnet), or it doesn't offer exit node services, a
// blackhole route will be installed on the local system to
// prevent any traffic escaping to the local network.
ExitNodeID tailcfg.StableNodeID
ExitNodeIP netaddr.IP
// ExitNodeAllowLANAccess indicates whether locally accessible subnets should be
// routed directly or via the exit node.
ExitNodeAllowLANAccess bool
// CorpDNS specifies whether to install the Tailscale network's
// DNS configuration, if it exists.
CorpDNS bool
// RunSSH bool is whether this node should run an SSH
// server, permitting access to peers according to the
// policies as configured by the Tailnet's admin(s).
RunSSH bool
// WantRunning indicates whether networking should be active on
// this node.
WantRunning bool
// LoggedOut indicates whether the user intends to be logged out.
// There are other reasons we may be logged out, including no valid
// keys.
// We need to remember this state so that, on next startup, we can
// generate the "Login" vs "Connect" buttons correctly, without having
// to contact the server to confirm our nodekey status first.
LoggedOut bool
// ShieldsUp indicates whether to block all incoming connections,
// regardless of the control-provided packet filter. If false, we
// use the packet filter as provided. If true, we block incoming
// connections. This overrides tailcfg.Hostinfo's ShieldsUp.
ShieldsUp bool
// AdvertiseTags specifies groups that this node wants to join, for
// purposes of ACL enforcement. These can be referenced from the ACL
// security policy. Note that advertising a tag doesn't guarantee that
// the control server will allow you to take on the rights for that
// tag.
AdvertiseTags []string
// Hostname is the hostname to use for identifying the node. If
// not set, os.Hostname is used.
Hostname string
// NotepadURLs is a debugging setting that opens OAuth URLs in
// notepad.exe on Windows, rather than loading them in a browser.
//
// apenwarr 2020-04-29: Unfortunately this is still needed sometimes.
// Windows' default browser setting is sometimes screwy and this helps
// users narrow it down a bit.
NotepadURLs bool
// ForceDaemon specifies whether a platform that normally
// operates in "client mode" (that is, requires an active user
// logged in with the GUI app running) should keep running after the
// GUI ends and/or the user logs out.
//
// The only current applicable platform is Windows. This
// forced Windows to go into "server mode" where Tailscale is
// running even with no users logged in. This might also be
// used for macOS in the future. This setting has no effect
// for Linux/etc, which always operate in daemon mode.
ForceDaemon bool `json:"ForceDaemon,omitempty"`
// The following block of options only have an effect on Linux.
// AdvertiseRoutes specifies CIDR prefixes to advertise into the
// Tailscale network as reachable through the current
// node.
AdvertiseRoutes []netaddr.IPPrefix
// NoSNAT specifies whether to source NAT traffic going to
// destinations in AdvertiseRoutes. The default is to apply source
// NAT, which makes the traffic appear to come from the router
// machine rather than the peer's Tailscale IP.
//
// Disabling SNAT requires additional manual configuration in your
// network to route Tailscale traffic back to the subnet relay
// machine.
//
// Linux-only.
NoSNAT bool
// NetfilterMode specifies how much to manage netfilter rules for
// Tailscale, if at all.
NetfilterMode preftype.NetfilterMode
// OperatorUser is the local machine user name who is allowed to
// operate tailscaled without being root or using sudo.
OperatorUser string `json:",omitempty"`
// The Persist field is named 'Config' in the file for backward
// compatibility with earlier versions.
// TODO(apenwarr): We should move this out of here, it's not a pref.
// We can maybe do that once we're sure which module should persist
// it (backend or frontend?)
Persist *persist.Persist `json:"Config"`
}
// MaskedPrefs is a Prefs with an associated bitmask of which fields are set.
type MaskedPrefs struct {
Prefs
ControlURLSet bool `json:",omitempty"`
RouteAllSet bool `json:",omitempty"`
AllowSingleHostsSet bool `json:",omitempty"`
ExitNodeIDSet bool `json:",omitempty"`
ExitNodeIPSet bool `json:",omitempty"`
ExitNodeAllowLANAccessSet bool `json:",omitempty"`
CorpDNSSet bool `json:",omitempty"`
RunSSHSet bool `json:",omitempty"`
WantRunningSet bool `json:",omitempty"`
LoggedOutSet bool `json:",omitempty"`
ShieldsUpSet bool `json:",omitempty"`
AdvertiseTagsSet bool `json:",omitempty"`
HostnameSet bool `json:",omitempty"`
NotepadURLsSet bool `json:",omitempty"`
ForceDaemonSet bool `json:",omitempty"`
AdvertiseRoutesSet bool `json:",omitempty"`
NoSNATSet bool `json:",omitempty"`
NetfilterModeSet bool `json:",omitempty"`
OperatorUserSet bool `json:",omitempty"`
}
// ApplyEdits mutates p, assigning fields from m.Prefs for each MaskedPrefs
// Set field that's true.
func (p *Prefs) ApplyEdits(m *MaskedPrefs) {
if p == nil {
panic("can't edit nil Prefs")
}
pv := reflect.ValueOf(p).Elem()
mv := reflect.ValueOf(m).Elem()
mpv := reflect.ValueOf(&m.Prefs).Elem()
fields := mv.NumField()
for i := 1; i < fields; i++ {
if mv.Field(i).Bool() {
newFieldValue := mpv.Field(i - 1)
pv.Field(i - 1).Set(newFieldValue)
}
}
}
func (m *MaskedPrefs) Pretty() string {
if m == nil {
return "MaskedPrefs{<nil>}"
}
var sb strings.Builder
sb.WriteString("MaskedPrefs{")
mv := reflect.ValueOf(m).Elem()
mt := mv.Type()
mpv := reflect.ValueOf(&m.Prefs).Elem()
first := true
format := func(v reflect.Value) string {
switch v.Type().Kind() {
case reflect.String:
return "%s=%q"
case reflect.Slice:
// []string
if v.Type().Elem().Kind() == reflect.String {
return "%s=%q"
}
}
return "%s=%v"
}
for i := 1; i < mt.NumField(); i++ {
name := mt.Field(i).Name
if mv.Field(i).Bool() {
if !first {
sb.WriteString(" ")
}
first = false
f := mpv.Field(i - 1)
fmt.Fprintf(&sb, format(f),
strings.TrimSuffix(name, "Set"),
f.Interface())
}
}
sb.WriteString("}")
return sb.String()
}
// IsEmpty reports whether p is nil or pointing to a Prefs zero value.
func (p *Prefs) IsEmpty() bool { return p == nil || p.Equals(&Prefs{}) }
func (p *Prefs) Pretty() string { return p.pretty(runtime.GOOS) }
func (p *Prefs) pretty(goos string) string {
var sb strings.Builder
sb.WriteString("Prefs{")
fmt.Fprintf(&sb, "ra=%v ", p.RouteAll)
if !p.AllowSingleHosts {
sb.WriteString("mesh=false ")
}
fmt.Fprintf(&sb, "dns=%v want=%v ", p.CorpDNS, p.WantRunning)
if p.RunSSH {
sb.WriteString("ssh=true ")
}
if p.LoggedOut {
sb.WriteString("loggedout=true ")
}
if p.ForceDaemon {
sb.WriteString("server=true ")
}
if p.NotepadURLs {
sb.WriteString("notepad=true ")
}
if p.ShieldsUp {
sb.WriteString("shields=true ")
}
if !p.ExitNodeIP.IsZero() {
fmt.Fprintf(&sb, "exit=%v lan=%t ", p.ExitNodeIP, p.ExitNodeAllowLANAccess)
} else if !p.ExitNodeID.IsZero() {
fmt.Fprintf(&sb, "exit=%v lan=%t ", p.ExitNodeID, p.ExitNodeAllowLANAccess)
}
if len(p.AdvertiseRoutes) > 0 || goos == "linux" {
fmt.Fprintf(&sb, "routes=%v ", p.AdvertiseRoutes)
}
if len(p.AdvertiseRoutes) > 0 || p.NoSNAT {
fmt.Fprintf(&sb, "snat=%v ", !p.NoSNAT)
}
if len(p.AdvertiseTags) > 0 {
fmt.Fprintf(&sb, "tags=%s ", strings.Join(p.AdvertiseTags, ","))
}
if goos == "linux" {
fmt.Fprintf(&sb, "nf=%v ", p.NetfilterMode)
}
if p.ControlURL != "" && p.ControlURL != DefaultControlURL {
fmt.Fprintf(&sb, "url=%q ", p.ControlURL)
}
if p.Hostname != "" {
fmt.Fprintf(&sb, "host=%q ", p.Hostname)
}
if p.OperatorUser != "" {
fmt.Fprintf(&sb, "op=%q ", p.OperatorUser)
}
if p.Persist != nil {
sb.WriteString(p.Persist.Pretty())
} else {
sb.WriteString("Persist=nil")
}
sb.WriteString("}")
return sb.String()
}
func (p *Prefs) ToBytes() []byte {
data, err := json.MarshalIndent(p, "", "\t")
if err != nil {
log.Fatalf("Prefs marshal: %v\n", err)
}
return data
}
func (p *Prefs) Equals(p2 *Prefs) bool {
if p == nil && p2 == nil {
return true
}
if p == nil || p2 == nil {
return false
}
return p != nil && p2 != nil &&
p.ControlURL == p2.ControlURL &&
p.RouteAll == p2.RouteAll &&
p.AllowSingleHosts == p2.AllowSingleHosts &&
p.ExitNodeID == p2.ExitNodeID &&
p.ExitNodeIP == p2.ExitNodeIP &&
p.ExitNodeAllowLANAccess == p2.ExitNodeAllowLANAccess &&
p.CorpDNS == p2.CorpDNS &&
p.RunSSH == p2.RunSSH &&
p.WantRunning == p2.WantRunning &&
p.LoggedOut == p2.LoggedOut &&
p.NotepadURLs == p2.NotepadURLs &&
p.ShieldsUp == p2.ShieldsUp &&
p.NoSNAT == p2.NoSNAT &&
p.NetfilterMode == p2.NetfilterMode &&
p.OperatorUser == p2.OperatorUser &&
p.Hostname == p2.Hostname &&
p.ForceDaemon == p2.ForceDaemon &&
compareIPNets(p.AdvertiseRoutes, p2.AdvertiseRoutes) &&
compareStrings(p.AdvertiseTags, p2.AdvertiseTags) &&
p.Persist.Equals(p2.Persist)
}
func compareIPNets(a, b []netaddr.IPPrefix) bool {
if len(a) != len(b) {
return false
}
for i := range a {
if a[i] != b[i] {
return false
}
}
return true
}
func compareStrings(a, b []string) bool {
if len(a) != len(b) {
return false
}
for i := range a {
if a[i] != b[i] {
return false
}
}
return true
}
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
// NewPrefs returns the default preferences to use.
func NewPrefs() *Prefs {
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
// Provide default values for options which might be missing
// from the json data for any reason. The json can still
// override them to false.
return &Prefs{
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
// ControlURL is explicitly not set to signal that
// it's not yet configured, which relaxes the CLI "up"
// safety net features. It will get set to DefaultControlURL
// on first up. Or, if not, DefaultControlURL will be used
// later anyway.
ControlURL: "",
RouteAll: true,
AllowSingleHosts: true,
CorpDNS: true,
WantRunning: false,
NetfilterMode: preftype.NetfilterOn,
}
}
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
// ControlURLOrDefault returns the coordination server's URL base.
//
// If not configured, or if the configured value is a legacy name equivalent to
// the default, then DefaultControlURL is returned instead.
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
func (p *Prefs) ControlURLOrDefault() string {
if p.ControlURL != "" {
if p.ControlURL != DefaultControlURL && IsLoginServerSynonym(p.ControlURL) {
return DefaultControlURL
}
ipn{,/ipnlocal}, cmd/tailscale/cli: don't check pref reverts on initial up The ipn.NewPrefs func returns a populated ipn.Prefs for historical reasons. It's not used or as important as it once was, but it hasn't yet been removed. Meanwhile, it contains some default values that are used on some platforms. Notably, for this bug (#1725), Windows/Mac use its Prefs.RouteAll true value (to accept subnets), but Linux users have always gotten a "false" value for that, because that's what cmd/tailscale's CLI default flag is _for all operating systems_. That meant that "tailscale up" was rightfully reporting that the user was changing an implicit setting: RouteAll was changing from true with false with the user explicitly saying so. An obvious fix might be to change ipn.NewPrefs to return Prefs.RouteAll == false on some platforms, but the logic is complicated by darwin: we want RouteAll true on windows, android, ios, and the GUI mac app, but not the CLI tailscaled-on-macOS mode. But even if we used build tags (e.g. the "redo" build tag) to determine what the default is, that then means we have duplicated and differing "defaults" between both the CLI up flags and ipn.NewPrefs. Furthering that complication didn't seem like a good idea. So, changing the NewPrefs defaults is too invasive at this stage of the release, as is removing the NewPrefs func entirely. Instead, tweak slightly the semantics of the ipn.Prefs.ControlURL field. This now defines that a ControlURL of the empty string means both "we're uninitialized" and also "just use the default". Then, once we have the "empty-string-means-unintialized" semantics, use that to suppress "tailscale up"'s recent implicit-setting-revert checking safety net, if we've never initialized Tailscale yet. And update/add tests. Fixes #1725 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
return p.ControlURL
}
return DefaultControlURL
}
// AdminPageURL returns the admin web site URL for the current ControlURL.
func (p *Prefs) AdminPageURL() string {
url := p.ControlURLOrDefault()
if IsLoginServerSynonym(url) {
// TODO(crawshaw): In future release, make this https://console.tailscale.com
url = "https://login.tailscale.com"
}
return url + "/admin/machines"
}
// AdvertisesExitNode reports whether p is advertising both the v4 and
// v6 /0 exit node routes.
func (p *Prefs) AdvertisesExitNode() bool {
if p == nil {
return false
}
return tsaddr.ContainsExitRoutes(p.AdvertiseRoutes)
}
// SetAdvertiseExitNode mutates p (if non-nil) to add or remove the two
// /0 exit node routes.
func (p *Prefs) SetAdvertiseExitNode(runExit bool) {
if p == nil {
return
}
all := p.AdvertiseRoutes
p.AdvertiseRoutes = p.AdvertiseRoutes[:0]
for _, r := range all {
if r.Bits() != 0 {
p.AdvertiseRoutes = append(p.AdvertiseRoutes, r)
}
}
if !runExit {
return
}
p.AdvertiseRoutes = append(p.AdvertiseRoutes,
netaddr.IPPrefixFrom(netaddr.IPv4(0, 0, 0, 0), 0),
netaddr.IPPrefixFrom(netaddr.IPv6Unspecified(), 0))
}
// peerWithTailscaleIP returns the peer in st with the provided
// Tailscale IP.
func peerWithTailscaleIP(st *ipnstate.Status, ip netaddr.IP) (ps *ipnstate.PeerStatus, ok bool) {
for _, ps := range st.Peer {
for _, ip2 := range ps.TailscaleIPs {
if ip == ip2 {
return ps, true
}
}
}
return nil, false
}
func isRemoteIP(st *ipnstate.Status, ip netaddr.IP) bool {
for _, selfIP := range st.TailscaleIPs {
if ip == selfIP {
return false
}
}
return true
}
// ClearExitNode sets the ExitNodeID and ExitNodeIP to their zero values.
func (p *Prefs) ClearExitNode() {
p.ExitNodeID = ""
p.ExitNodeIP = netaddr.IP{}
}
// ExitNodeLocalIPError is returned when the requested IP address for an exit
// node belongs to the local machine.
type ExitNodeLocalIPError struct {
hostOrIP string
}
func (e ExitNodeLocalIPError) Error() string {
return fmt.Sprintf("cannot use %s as an exit node as it is a local IP address to this machine", e.hostOrIP)
}
func exitNodeIPOfArg(s string, st *ipnstate.Status) (ip netaddr.IP, err error) {
if s == "" {
return ip, os.ErrInvalid
}
ip, err = netaddr.ParseIP(s)
if err == nil {
// If we're online already and have a netmap, double check that the IP
// address specified is valid.
if st.BackendState == "Running" {
ps, ok := peerWithTailscaleIP(st, ip)
if !ok {
return ip, fmt.Errorf("no node found in netmap with IP %v", ip)
}
if !ps.ExitNodeOption {
return ip, fmt.Errorf("node %v is not advertising an exit node", ip)
}
}
if !isRemoteIP(st, ip) {
return ip, ExitNodeLocalIPError{s}
}
return ip, nil
}
match := 0
for _, ps := range st.Peer {
baseName := dnsname.TrimSuffix(ps.DNSName, st.MagicDNSSuffix)
if !strings.EqualFold(s, baseName) {
continue
}
match++
if len(ps.TailscaleIPs) == 0 {
return ip, fmt.Errorf("node %q has no Tailscale IP?", s)
}
if !ps.ExitNodeOption {
return ip, fmt.Errorf("node %q is not advertising an exit node", s)
}
ip = ps.TailscaleIPs[0]
}
switch match {
case 0:
return ip, fmt.Errorf("invalid value %q for --exit-node; must be IP or unique node name", s)
case 1:
if !isRemoteIP(st, ip) {
return ip, ExitNodeLocalIPError{s}
}
return ip, nil
default:
return ip, fmt.Errorf("ambiguous exit node name %q", s)
}
}
// SetExitNodeIP validates and sets the ExitNodeIP from a user-provided string
// specifying either an IP address or a MagicDNS base name ("foo", as opposed to
// "foo.bar.beta.tailscale.net"). This method does not mutate ExitNodeID and
// will fail if ExitNodeID is already set.
func (p *Prefs) SetExitNodeIP(s string, st *ipnstate.Status) error {
if !p.ExitNodeID.IsZero() {
return ErrExitNodeIDAlreadySet
}
ip, err := exitNodeIPOfArg(s, st)
if err == nil {
p.ExitNodeIP = ip
}
return err
}
// ShouldSSHBeRunning reports whether the SSH server should be running based on
// the prefs.
func (p *Prefs) ShouldSSHBeRunning() bool {
return p.WantRunning && p.RunSSH
}
// PrefsFromBytes deserializes Prefs from a JSON blob.
func PrefsFromBytes(b []byte) (*Prefs, error) {
p := NewPrefs()
if len(b) == 0 {
return p, nil
}
persist := &persist.Persist{}
err := json.Unmarshal(b, persist)
if err == nil && (persist.Provider != "" || persist.LoginName != "") {
// old-style relaynode config; import it
p.Persist = persist
} else {
err = json.Unmarshal(b, &p)
if err != nil {
log.Printf("Prefs parse: %v: %v\n", err, b)
}
}
return p, err
}
// LoadPrefs loads a legacy relaynode config file into Prefs
// with sensible migration defaults set.
func LoadPrefs(filename string) (*Prefs, error) {
data, err := ioutil.ReadFile(filename)
if err != nil {
return nil, fmt.Errorf("LoadPrefs open: %w", err) // err includes path
}
if bytes.Contains(data, jsonEscapedZero) {
// Tailscale 1.2.0 - 1.2.8 on Windows had a memory corruption bug
// in the backend process that ended up sending NULL bytes over JSON
// to the frontend which wrote them out to JSON files on disk.
// So if we see one, treat is as corrupt and the user will need
// to log in again. (better than crashing)
return nil, os.ErrNotExist
}
p, err := PrefsFromBytes(data)
if err != nil {
return nil, fmt.Errorf("LoadPrefs(%q) decode: %w", filename, err)
}
return p, nil
}
func SavePrefs(filename string, p *Prefs) {
log.Printf("Saving prefs %v %v\n", filename, p.Pretty())
data := p.ToBytes()
os.MkdirAll(filepath.Dir(filename), 0700)
if err := atomicfile.WriteFile(filename, data, 0600); err != nil {
log.Printf("SavePrefs: %v\n", err)
}
}