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tailscale/ipn/ipnlocal/tailfs.go

386 lines
10 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package ipnlocal
import (
"errors"
"fmt"
"os"
"regexp"
"slices"
"strings"
"tailscale.com/ipn"
"tailscale.com/tailcfg"
"tailscale.com/tailfs"
"tailscale.com/types/netmap"
"tailscale.com/types/views"
)
const (
// TailFSLocalPort is the port on which the TailFS listens for location
// connections on quad 100.
TailFSLocalPort = 8080
)
var (
shareNameRegex = regexp.MustCompile(`^[a-z0-9_\(\) ]+$`)
ErrTailFSNotEnabled = errors.New("TailFS not enabled")
ErrInvalidShareName = errors.New("Share names may only contain the letters a-z, underscore _, parentheses (), or spaces")
)
// TailFSSharingEnabled reports whether sharing to remote nodes via tailfs is
// enabled. This is currently based on checking for the tailfs:share node
// attribute.
func (b *LocalBackend) TailFSSharingEnabled() bool {
b.mu.Lock()
defer b.mu.Unlock()
return b.tailFSSharingEnabledLocked()
}
func (b *LocalBackend) tailFSSharingEnabledLocked() bool {
return b.netMap != nil && b.netMap.SelfNode.HasCap(tailcfg.NodeAttrsTailFSShare)
}
// TailFSAccessEnabled reports whether accessing TailFS shares on remote nodes
// is enabled. This is currently based on checking for the tailfs:access node
// attribute.
func (b *LocalBackend) TailFSAccessEnabled() bool {
b.mu.Lock()
defer b.mu.Unlock()
return b.tailFSAccessEnabledLocked()
}
func (b *LocalBackend) tailFSAccessEnabledLocked() bool {
return b.netMap != nil && b.netMap.SelfNode.HasCap(tailcfg.NodeAttrsTailFSAccess)
}
// TailFSSetFileServerAddr tells tailfs to use the given address for connecting
// to the tailfs.FileServer that's exposing local files as an unprivileged
// user.
func (b *LocalBackend) TailFSSetFileServerAddr(addr string) error {
fs, ok := b.sys.TailFSForRemote.GetOK()
if !ok {
return ErrTailFSNotEnabled
}
fs.SetFileServerAddr(addr)
return nil
}
// TailFSSetShare adds the given share if no share with that name exists, or
// replaces the existing share if one with the same name already exists. To
// avoid potential incompatibilities across file systems, share names are
// limited to alphanumeric characters and the underscore _.
func (b *LocalBackend) TailFSSetShare(share *tailfs.Share) error {
var err error
share.Name, err = normalizeShareName(share.Name)
if err != nil {
return err
}
b.mu.Lock()
shares, err := b.tailFSSetShareLocked(share)
b.mu.Unlock()
if err != nil {
return err
}
b.tailFSNotifyShares(shares)
return nil
}
// normalizeShareName normalizes the given share name and returns an error if
// it contains any disallowed characters.
func normalizeShareName(name string) (string, error) {
// Force all share names to lowercase to avoid potential incompatibilities
// with clients that don't support case-sensitive filenames.
name = strings.ToLower(name)
// Trim whitespace
name = strings.TrimSpace(name)
if !shareNameRegex.MatchString(name) {
return "", ErrInvalidShareName
}
return name, nil
}
func (b *LocalBackend) tailFSSetShareLocked(share *tailfs.Share) (views.SliceView[*tailfs.Share, tailfs.ShareView], error) {
existingShares := b.pm.prefs.TailFSShares()
fs, ok := b.sys.TailFSForRemote.GetOK()
if !ok {
return existingShares, ErrTailFSNotEnabled
}
addedShare := false
var shares []*tailfs.Share
for i := 0; i < existingShares.Len(); i++ {
existing := existingShares.At(i)
if existing.Name() != share.Name {
if !addedShare && existing.Name() > share.Name {
// Add share in order
shares = append(shares, share)
addedShare = true
}
shares = append(shares, existing.AsStruct())
}
}
if !addedShare {
shares = append(shares, share)
}
err := b.tailFSSetSharesLocked(shares)
if err != nil {
return existingShares, err
}
fs.SetShares(shares)
return b.pm.prefs.TailFSShares(), nil
}
// TailFSRenameShare renames the share at old name to new name. To avoid
// potential incompatibilities across file systems, the new share name is
// limited to alphanumeric characters and the underscore _.
// Any of the following will result in an error.
// - no share found under old name
// - new share name contains disallowed characters
// - share already exists under new name
func (b *LocalBackend) TailFSRenameShare(oldName, newName string) error {
var err error
newName, err = normalizeShareName(newName)
if err != nil {
return err
}
b.mu.Lock()
shares, err := b.tailFSRenameShareLocked(oldName, newName)
b.mu.Unlock()
if err != nil {
return err
}
b.tailFSNotifyShares(shares)
return nil
}
func (b *LocalBackend) tailFSRenameShareLocked(oldName, newName string) (views.SliceView[*tailfs.Share, tailfs.ShareView], error) {
existingShares := b.pm.prefs.TailFSShares()
fs, ok := b.sys.TailFSForRemote.GetOK()
if !ok {
return existingShares, ErrTailFSNotEnabled
}
found := false
var shares []*tailfs.Share
for i := 0; i < existingShares.Len(); i++ {
existing := existingShares.At(i)
if existing.Name() == newName {
return existingShares, os.ErrExist
}
if existing.Name() == oldName {
share := existing.AsStruct()
share.Name = newName
shares = append(shares, share)
found = true
} else {
shares = append(shares, existing.AsStruct())
}
}
if !found {
return existingShares, os.ErrNotExist
}
slices.SortFunc(shares, tailfs.CompareShares)
err := b.tailFSSetSharesLocked(shares)
if err != nil {
return existingShares, err
}
fs.SetShares(shares)
return b.pm.prefs.TailFSShares(), nil
}
// TailFSRemoveShare removes the named share. Share names are forced to
// lowercase.
func (b *LocalBackend) TailFSRemoveShare(name string) error {
// Force all share names to lowercase to avoid potential incompatibilities
// with clients that don't support case-sensitive filenames.
var err error
name, err = normalizeShareName(name)
if err != nil {
return err
}
b.mu.Lock()
shares, err := b.tailFSRemoveShareLocked(name)
b.mu.Unlock()
if err != nil {
return err
}
b.tailFSNotifyShares(shares)
return nil
}
func (b *LocalBackend) tailFSRemoveShareLocked(name string) (views.SliceView[*tailfs.Share, tailfs.ShareView], error) {
existingShares := b.pm.prefs.TailFSShares()
fs, ok := b.sys.TailFSForRemote.GetOK()
if !ok {
return existingShares, ErrTailFSNotEnabled
}
found := false
var shares []*tailfs.Share
for i := 0; i < existingShares.Len(); i++ {
existing := existingShares.At(i)
if existing.Name() != name {
shares = append(shares, existing.AsStruct())
} else {
found = true
}
}
if !found {
return existingShares, os.ErrNotExist
}
err := b.tailFSSetSharesLocked(shares)
if err != nil {
return existingShares, err
}
fs.SetShares(shares)
return b.pm.prefs.TailFSShares(), nil
}
func (b *LocalBackend) tailFSSetSharesLocked(shares []*tailfs.Share) error {
prefs := b.pm.prefs.AsStruct()
prefs.ApplyEdits(&ipn.MaskedPrefs{
Prefs: ipn.Prefs{
TailFSShares: shares,
},
TailFSSharesSet: true,
})
return b.pm.setPrefsLocked(prefs.View())
}
// tailFSNotifyShares notifies IPN bus listeners (e.g. Mac Application process)
// about the latest list of shares.
func (b *LocalBackend) tailFSNotifyShares(shares views.SliceView[*tailfs.Share, tailfs.ShareView]) {
// Ensures shares is not nil to distinguish "no shares" from "not notifying shares"
if shares.IsNil() {
shares = views.SliceOfViews(make([]*tailfs.Share, 0))
}
b.send(ipn.Notify{TailFSShares: shares})
}
// tailFSNotifyCurrentSharesLocked sends an ipn.Notify if the current set of
// shares has changed since the last notification.
func (b *LocalBackend) tailFSNotifyCurrentSharesLocked() {
var shares views.SliceView[*tailfs.Share, tailfs.ShareView]
if b.tailFSSharingEnabledLocked() {
// Only populate shares if sharing is enabled.
shares = b.pm.prefs.TailFSShares()
}
lastNotified := b.lastNotifiedTailFSShares.Load()
if lastNotified == nil || !tailFSShareViewsEqual(lastNotified, shares) {
// Do the below on a goroutine to avoid deadlocking on b.mu in b.send().
go b.tailFSNotifyShares(shares)
}
}
func tailFSShareViewsEqual(a *views.SliceView[*tailfs.Share, tailfs.ShareView], b views.SliceView[*tailfs.Share, tailfs.ShareView]) bool {
if a == nil {
return false
}
if a.Len() != b.Len() {
return false
}
for i := 0; i < a.Len(); i++ {
if !tailfs.ShareViewsEqual(a.At(i), b.At(i)) {
return false
}
}
return true
}
// TailFSGetShares() gets the current list of TailFS shares, sorted by name.
func (b *LocalBackend) TailFSGetShares() views.SliceView[*tailfs.Share, tailfs.ShareView] {
b.mu.Lock()
defer b.mu.Unlock()
return b.pm.prefs.TailFSShares()
}
// updateTailFSPeersLocked sets all applicable peers from the netmap as tailfs
// remotes.
func (b *LocalBackend) updateTailFSPeersLocked(nm *netmap.NetworkMap) {
fs, ok := b.sys.TailFSForLocal.GetOK()
if !ok {
return
}
var tailFSRemotes []*tailfs.Remote
if b.tailFSAccessEnabledLocked() {
// Only populate peers if access is enabled, otherwise leave blank.
tailFSRemotes = b.tailFSRemotesFromPeers(nm)
}
fs.SetRemotes(b.netMap.Domain, tailFSRemotes, &tailFSTransport{b: b})
}
func (b *LocalBackend) tailFSRemotesFromPeers(nm *netmap.NetworkMap) []*tailfs.Remote {
tailFSRemotes := make([]*tailfs.Remote, 0, len(nm.Peers))
for _, p := range nm.Peers {
// Exclude mullvad exit nodes from list of TailFS peers
// TODO(oxtoacart) - once we have a better mechanism for finding only accessible sharers
// (see below) we can remove this logic.
if strings.HasSuffix(p.Name(), ".mullvad.ts.net.") {
continue
}
peerID := p.ID()
url := fmt.Sprintf("%s/%s", peerAPIBase(nm, p), tailFSPrefix[1:])
tailFSRemotes = append(tailFSRemotes, &tailfs.Remote{
Name: p.DisplayName(false),
URL: url,
Available: func() bool {
// TODO(oxtoacart): need to figure out a performant and reliable way to only
// show the peers that have shares to which we have access
// This will require work on the control server to transmit the inverse
// of the "tailscale.com/cap/tailfs" capability.
// For now, at least limit it only to nodes that are online.
// Note, we have to iterate the latest netmap because the peer we got from the first iteration may not be it
b.mu.Lock()
latestNetMap := b.netMap
b.mu.Unlock()
for _, candidate := range latestNetMap.Peers {
if candidate.ID() == peerID {
online := candidate.Online()
// TODO(oxtoacart): for some reason, this correctly
// catches when a node goes from offline to online,
// but not the other way around...
return online != nil && *online
}
}
// peer not found, must not be available
return false
},
})
}
return tailFSRemotes
}