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portlist: add Poller.IncludeLocalhost option

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This PR parameterizes receiving loopback updates from the portlist package.
Callers can now include services bound to localhost if they want.
Note that this option is off by default still.

Fixes #8171

Signed-off-by: Marwan Sulaiman <marwan@tailscale.com>
pull/8200/head
Marwan Sulaiman 2 years ago committed by Marwan Sulaiman
parent 3d180a16c3
commit e32e5c0d0c
9 changed files with 88 additions and 64 deletions
Show Stats Download Patch File Download Diff File

6
portlist/netstat.go
Unescape Escape View File

@ -67,7 +67,7 @@ type nothing struct{}
// Unfortunately, options to filter by proto or state are non-portable,
// so we'll filter for ourselves.
// Nowadays, though, we only use it for macOS as of 2022-11-04.
func appendParsePortsNetstat(base []Port, br *bufio.Reader) ([]Port, error) {
func appendParsePortsNetstat(base []Port, br *bufio.Reader, includeLocalhost bool) ([]Port, error) {
ret := base
var fieldBuf [10]mem.RO
for {
@ -99,7 +99,7 @@ func appendParsePortsNetstat(base []Port, br *bufio.Reader) ([]Port, error) {
// not interested in non-listener sockets
continue
}
if isLoopbackAddr(laddr) {
if !includeLocalhost && isLoopbackAddr(laddr) {
// not interested in loopback-bound listeners
continue
}
@ -110,7 +110,7 @@ func appendParsePortsNetstat(base []Port, br *bufio.Reader) ([]Port, error) {
proto = "udp"
laddr = cols[len(cols)-2]
raddr = cols[len(cols)-1]
if isLoopbackAddr(laddr) {
if !includeLocalhost && isLoopbackAddr(laddr) {
// not interested in loopback-bound listeners
continue
}

61
portlist/netstat_test.go
Unescape Escape View File

@ -8,6 +8,7 @@ package portlist
import (
"bufio"
"encoding/json"
"fmt"
"strings"
"testing"
@ -52,30 +53,40 @@ udp46 0 0 *.146 *.*
`
func TestParsePortsNetstat(t *testing.T) {
want := List{
Port{"tcp", 23, ""},
Port{"tcp", 24, ""},
Port{"udp", 104, ""},
Port{"udp", 106, ""},
Port{"udp", 146, ""},
Port{"tcp", 8185, ""}, // but not 8186, 8187, 8188 on localhost
}
pl, err := appendParsePortsNetstat(nil, bufio.NewReader(strings.NewReader(netstatOutput)))
if err != nil {
t.Fatal(err)
}
pl = sortAndDedup(pl)
jgot, _ := json.MarshalIndent(pl, "", "\t")
jwant, _ := json.MarshalIndent(want, "", "\t")
if len(pl) != len(want) {
t.Fatalf("Got:\n%s\n\nWant:\n%s\n", jgot, jwant)
}
for i := range pl {
if pl[i] != want[i] {
t.Errorf("row#%d\n got: %+v\n\nwant: %+v\n",
i, pl[i], want[i])
t.Fatalf("Got:\n%s\n\nWant:\n%s\n", jgot, jwant)
}
for _, loopBack := range [...]bool{false, true} {
t.Run(fmt.Sprintf("loopback_%v", loopBack), func(t *testing.T) {
want := List{
{"tcp", 23, "", 0},
{"tcp", 24, "", 0},
{"udp", 104, "", 0},
{"udp", 106, "", 0},
{"udp", 146, "", 0},
{"tcp", 8185, "", 0}, // but not 8186, 8187, 8188 on localhost, when loopback is false
}
if loopBack {
want = append(want,
Port{"tcp", 8186, "", 0},
Port{"tcp", 8187, "", 0},
Port{"tcp", 8188, "", 0},
)
}
pl, err := appendParsePortsNetstat(nil, bufio.NewReader(strings.NewReader(netstatOutput)), loopBack)
if err != nil {
t.Fatal(err)
}
pl = sortAndDedup(pl)
jgot, _ := json.MarshalIndent(pl, "", "\t")
jwant, _ := json.MarshalIndent(want, "", "\t")
if len(pl) != len(want) {
t.Fatalf("Got:\n%s\n\nWant:\n%s\n", jgot, jwant)
}
for i := range pl {
if pl[i] != want[i] {
t.Errorf("row#%d\n got: %+v\n\nwant: %+v\n",
i, pl[i], want[i])
t.Fatalf("Got:\n%s\n\nWant:\n%s\n", jgot, jwant)
}
}
})
}
}

9
portlist/poller.go
Unescape Escape View File

@ -24,6 +24,11 @@ var debugDisablePortlist = envknob.RegisterBool("TS_DEBUG_DISABLE_PORTLIST")
// Poller scans the systems for listening ports periodically and sends
// the results to C.
type Poller struct {
// IncludeLocalhost controls whether services bound to localhost are included.
//
// This field should only be changed before calling Run.
IncludeLocalhost bool
c chan List // unbuffered
// os, if non-nil, is an OS-specific implementation of the portlist getting
@ -62,7 +67,7 @@ type osImpl interface {
}
// newOSImpl, if non-nil, constructs a new osImpl.
var newOSImpl func() osImpl
var newOSImpl func(includeLocalhost bool) osImpl
var errUnimplemented = errors.New("portlist poller not implemented on " + runtime.GOOS)
@ -100,7 +105,7 @@ func (p *Poller) setPrev(pl List) {
func (p *Poller) initOSField() {
if newOSImpl != nil {
p.os = newOSImpl()
p.os = newOSImpl(p.IncludeLocalhost)
}
}

6
portlist/portlist.go
Unescape Escape View File

@ -18,6 +18,7 @@ type Port struct {
Proto string // "tcp" or "udp"
Port uint16 // port number
Process string // optional process name, if found
Pid int // process id, if known
}
// List is a list of Ports.
@ -69,12 +70,11 @@ func sortAndDedup(ps List) List {
out := ps[:0]
var last Port
for _, p := range ps {
protoPort := Port{Proto: p.Proto, Port: p.Port}
if last == protoPort {
if last.Proto == p.Proto && last.Port == p.Port {
continue
}
out = append(out, p)
last = protoPort
last = p
}
return out
}

22
portlist/portlist_linux.go
Unescape Escape View File

@ -35,25 +35,28 @@ type linuxImpl struct {
procNetFiles []*os.File // seeked to start & reused between calls
readlinkPathBuf []byte
known map[string]*portMeta // inode string => metadata
br *bufio.Reader
known map[string]*portMeta // inode string => metadata
br *bufio.Reader
includeLocalhost bool
}
type portMeta struct {
port Port
pid int
keep bool
needsProcName bool
}
func newLinuxImplBase() *linuxImpl {
func newLinuxImplBase(includeLocalhost bool) *linuxImpl {
return &linuxImpl{
br: bufio.NewReader(eofReader),
known: map[string]*portMeta{},
br: bufio.NewReader(eofReader),
known: map[string]*portMeta{},
includeLocalhost: includeLocalhost,
}
}
func newLinuxImpl() osImpl {
li := newLinuxImplBase()
func newLinuxImpl(includeLocalhost bool) osImpl {
li := newLinuxImplBase(includeLocalhost)
for _, name := range []string{
"/proc/net/tcp",
"/proc/net/tcp6",
@ -220,7 +223,7 @@ func (li *linuxImpl) parseProcNetFile(r *bufio.Reader, fileBase string) error {
// If a port is bound to localhost, ignore it.
// TODO: localhost is bigger than 1 IP, we need to ignore
// more things.
if mem.HasPrefix(local, mem.S(v4Localhost)) || mem.HasPrefix(local, mem.S(v6Localhost)) {
if !li.includeLocalhost && (mem.HasPrefix(local, mem.S(v4Localhost)) || mem.HasPrefix(local, mem.S(v6Localhost))) {
continue
}
@ -315,6 +318,9 @@ func (li *linuxImpl) findProcessNames(need map[string]*portMeta) error {
}
argv := strings.Split(strings.TrimSuffix(string(bs), "\x00"), "\x00")
if p, err := mem.ParseInt(pid, 10, 0); err == nil {
pe.pid = int(p)
}
pe.port.Process = argvSubject(argv...)
pe.needsProcName = false
delete(need, string(targetBuf[:n]))

4
portlist/portlist_linux_test.go
Unescape Escape View File

@ -89,7 +89,7 @@ func TestParsePorts(t *testing.T) {
if tt.file != "" {
file = tt.file
}
li := newLinuxImplBase()
li := newLinuxImplBase(false)
err := li.parseProcNetFile(r, file)
if err != nil {
t.Fatal(err)
@ -118,7 +118,7 @@ func BenchmarkParsePorts(b *testing.B) {
contents.WriteString(" 3: 69050120005716BC64906EBE009ECD4D:D506 0047062600000000000000006E171268:01BB 01 00000000:00000000 02:0000009E 00000000 1000 0 151042856 2 0000000000000000 21 4 28 10 -1\n")
}
li := newLinuxImplBase()
li := newLinuxImplBase(false)
r := bytes.NewReader(contents.Bytes())
br := bufio.NewReader(&contents)

20
portlist/portlist_macos.go
Unescape Escape View File

@ -29,8 +29,9 @@ type macOSImpl struct {
known map[protoPort]*portMeta // inode string => metadata
netstatPath string // lazily populated
br *bufio.Reader // reused
portsBuf []Port
br *bufio.Reader // reused
portsBuf []Port
includeLocalhost bool
}
type protoPort struct {
@ -43,10 +44,11 @@ type portMeta struct {
keep bool
}
func newMacOSImpl() osImpl {
func newMacOSImpl(includeLocalhost bool) osImpl {
return &macOSImpl{
known: map[protoPort]*portMeta{},
br: bufio.NewReader(bytes.NewReader(nil)),
known: map[protoPort]*portMeta{},
br: bufio.NewReader(bytes.NewReader(nil)),
includeLocalhost: includeLocalhost,
}
}
@ -119,7 +121,7 @@ func (im *macOSImpl) appendListeningPortsNetstat(base []Port) ([]Port, error) {
defer cmd.Process.Wait()
defer cmd.Process.Kill()
return appendParsePortsNetstat(base, im.br)
return appendParsePortsNetstat(base, im.br, im.includeLocalhost)
}
var lsofFailed atomic.Bool
@ -170,6 +172,7 @@ func (im *macOSImpl) addProcesses() error {
im.br.Reset(outPipe)
var cmd, proto string
var pid int
for {
line, err := im.br.ReadBytes('\n')
if err != nil {
@ -184,6 +187,10 @@ func (im *macOSImpl) addProcesses() error {
// starting a new process
cmd = ""
proto = ""
pid = 0
if p, err := mem.ParseInt(mem.B(val), 10, 0); err == nil {
pid = int(p)
}
case 'c':
cmd = string(val) // TODO(bradfitz): avoid garbage; cache process names between runs?
case 'P':
@ -202,6 +209,7 @@ func (im *macOSImpl) addProcesses() error {
switch {
case m != nil:
m.port.Process = cmd
m.port.Pid = pid
default:
// ignore: processes and ports come and go
}

13
portlist/portlist_test.go
Unescape Escape View File

@ -5,9 +5,7 @@ package portlist
import (
"context"
"flag"
"net"
"runtime"
"sync"
"testing"
"time"
@ -51,16 +49,9 @@ func TestIgnoreLocallyBoundPorts(t *testing.T) {
}
}
var flagRunUnspecTests = flag.Bool("run-unspec-tests",
runtime.GOOS == "linux", // other OSes have annoying firewall GUI confirmation dialogs
"run tests that require listening on the the unspecified address")
func TestChangesOverTime(t *testing.T) {
if !*flagRunUnspecTests {
t.Skip("skipping test without --run-unspec-tests")
}
var p Poller
p.IncludeLocalhost = true
get := func(t *testing.T) []Port {
t.Helper()
s, err := p.getList()
@ -71,7 +62,7 @@ func TestChangesOverTime(t *testing.T) {
}
p1 := get(t)
ln, err := net.Listen("tcp", ":0")
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Skipf("failed to bind: %v", err)
}

11
portlist/portlist_windows.go
Unescape Escape View File

@ -25,7 +25,8 @@ type famPort struct {
}
type windowsImpl struct {
known map[famPort]*portMeta // inode string => metadata
known map[famPort]*portMeta // inode string => metadata
includeLocalhost bool
}
type portMeta struct {
@ -33,9 +34,10 @@ type portMeta struct {
keep bool
}
func newWindowsImpl() osImpl {
func newWindowsImpl(includeLocalhost bool) osImpl {
return &windowsImpl{
known: map[famPort]*portMeta{},
known: map[famPort]*portMeta{},
includeLocalhost: includeLocalhost,
}
}
@ -58,7 +60,7 @@ func (im *windowsImpl) AppendListeningPorts(base []Port) ([]Port, error) {
if e.State != "LISTEN" {
continue
}
if !e.Local.Addr().IsUnspecified() {
if !im.includeLocalhost && !e.Local.Addr().IsUnspecified() {
continue
}
fp := famPort{
@ -83,6 +85,7 @@ func (im *windowsImpl) AppendListeningPorts(base []Port) ([]Port, error) {
Proto: "tcp",
Port: e.Local.Port(),
Process: process,
Pid: e.Pid,
},
}
im.known[fp] = pm

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