tailscale/cmd/derper/derper_test.go
Simon Law 3ee4c60ff0
cmd/derper: fix mesh auth for DERP servers (#16061)
To authenticate mesh keys, the DERP servers used a simple == comparison,
which is susceptible to a side channel timing attack.

By extracting the mesh key for a DERP server, an attacker could DoS it
by forcing disconnects using derp.Client.ClosePeer. They could also
enumerate the public Wireguard keys, IP addresses and ports for nodes
connected to that DERP server.

DERP servers configured without mesh keys deny all such requests.

This patch also extracts the mesh key logic into key.DERPMesh, to
prevent this from happening again.

Security bulletin: https://tailscale.com/security-bulletins#ts-2025-003

Fixes tailscale/corp#28720

Signed-off-by: Simon Law <sfllaw@tailscale.com>
2025-05-22 12:14:16 -07:00

141 lines
3.5 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package main
import (
"bytes"
"context"
"net/http"
"net/http/httptest"
"strings"
"testing"
"tailscale.com/derp/derphttp"
"tailscale.com/tstest/deptest"
)
func TestProdAutocertHostPolicy(t *testing.T) {
tests := []struct {
in string
wantOK bool
}{
{"derp.tailscale.com", true},
{"derp.tailscale.com.", true},
{"derp1.tailscale.com", true},
{"derp1b.tailscale.com", true},
{"derp2.tailscale.com", true},
{"derp02.tailscale.com", true},
{"derp-nyc.tailscale.com", true},
{"derpfoo.tailscale.com", true},
{"derp02.bar.tailscale.com", false},
{"example.net", false},
}
for _, tt := range tests {
got := prodAutocertHostPolicy(context.Background(), tt.in) == nil
if got != tt.wantOK {
t.Errorf("f(%q) = %v; want %v", tt.in, got, tt.wantOK)
}
}
}
func TestNoContent(t *testing.T) {
testCases := []struct {
name string
input string
want string
}{
{
name: "no challenge",
},
{
name: "valid challenge",
input: "input",
want: "response input",
},
{
name: "valid challenge hostname",
input: "ts_derp99b.tailscale.com",
want: "response ts_derp99b.tailscale.com",
},
{
name: "invalid challenge",
input: "foo\x00bar",
want: "",
},
{
name: "whitespace invalid challenge",
input: "foo bar",
want: "",
},
{
name: "long challenge",
input: strings.Repeat("x", 65),
want: "",
},
}
for _, tt := range testCases {
t.Run(tt.name, func(t *testing.T) {
req, _ := http.NewRequest("GET", "https://localhost/generate_204", nil)
if tt.input != "" {
req.Header.Set(derphttp.NoContentChallengeHeader, tt.input)
}
w := httptest.NewRecorder()
derphttp.ServeNoContent(w, req)
resp := w.Result()
if tt.want == "" {
if h, found := resp.Header[derphttp.NoContentResponseHeader]; found {
t.Errorf("got %+v; expected no response header", h)
}
return
}
if got := resp.Header.Get(derphttp.NoContentResponseHeader); got != tt.want {
t.Errorf("got %q; want %q", got, tt.want)
}
})
}
}
func TestDeps(t *testing.T) {
deptest.DepChecker{
BadDeps: map[string]string{
"testing": "do not use testing package in production code",
"gvisor.dev/gvisor/pkg/buffer": "https://github.com/tailscale/tailscale/issues/9756",
"gvisor.dev/gvisor/pkg/cpuid": "https://github.com/tailscale/tailscale/issues/9756",
"gvisor.dev/gvisor/pkg/tcpip": "https://github.com/tailscale/tailscale/issues/9756",
"gvisor.dev/gvisor/pkg/tcpip/header": "https://github.com/tailscale/tailscale/issues/9756",
"tailscale.com/net/packet": "not needed in derper",
"github.com/gaissmai/bart": "not needed in derper",
"database/sql/driver": "not needed in derper", // previously came in via github.com/google/uuid
},
}.Check(t)
}
func TestTemplate(t *testing.T) {
buf := &bytes.Buffer{}
err := homePageTemplate.Execute(buf, templateData{
ShowAbuseInfo: true,
Disabled: true,
AllowDebug: true,
})
if err != nil {
t.Fatal(err)
}
str := buf.String()
if !strings.Contains(str, "If you suspect abuse") {
t.Error("Output is missing abuse mailto")
}
if !strings.Contains(str, "Tailscale Security Policies") {
t.Error("Output is missing Tailscale Security Policies link")
}
if !strings.Contains(str, "Status:") {
t.Error("Output is missing disabled status")
}
if !strings.Contains(str, "Debug info") {
t.Error("Output is missing debug info")
}
}