tailscale/ipn/ipnauth/access_check_test.go
Nick Khyl 551d6ae0f3 ipn, ipn/ipnauth: implement API surface for LocalBackend access checking
We have a lot of access checks spread around the
ipnserver, ipnlocal, localapi, and ipnauth
packages, with a significant number of
platform-specific checks that are used exclusively
on either Windows or Unix-like platforms.
Additionally, with the exception of a few
Windows-specific checks, most of these checks are
per-device rather than per-profile, which is not
always correct even on single-user/single-session
environments, but even more problematic on
multi-user/multi-session environments such as
Windows.

We initially attempted to map all possible
operations onto the permitRead/permitWrite access
flags. However, these flags are not utilized on
Windows and prove insufficient on Unix machines.
Specifically, on Windows, the first user to
connect is granted full access, while subsequent
logged-in users have no access to the LocalAPI at
all. This restriction applies regardless of the
environment, local user roles (e.g., whether a
Windows user is a local admin), or whether they
are the active user on a shared Windows client
device. Conversely, on Unix, we introduced the
permitCert flag to enable granting non-root web
servers (such as www-data, caddy, nginx, etc.)
access to certificates. We also added additional
access check to distinguish local admins (root
on Unix-like platforms, elevated admins on
Windows) from users with permitWrite access,
and used it as a fix for the serve path LPE.

A more fine-grained access control system could
better suit our current and future needs, especially
in improving the UX across various scenarios on
corporate and personal Windows devices.

This adds an API surface in ipnauth that will be
used in LocalBackend to check access to individual
Tailscale profiles as well as any device-wide
information and operations.

Updates tailscale/corp#18342

Signed-off-by: Nick Khyl <nickk@tailscale.com>
2024-04-19 16:15:14 -05:00

551 lines
14 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package ipnauth
import (
"reflect"
"testing"
"tailscale.com/ipn"
"tailscale.com/tailcfg"
)
func TestAccessCheckResult(t *testing.T) {
tests := []struct {
name string
res AccessCheckResult
wantStr string
wantHasResult bool
wantAllow bool
wantDeny bool
wantErr bool
}{
{
name: "zero-value-implicit-deny",
res: AccessCheckResult{},
wantStr: "Implicit Deny",
wantHasResult: false,
wantAllow: false,
wantDeny: true,
wantErr: true,
},
{
name: "continue-implicit-deny",
res: ContinueCheck(),
wantStr: "Implicit Deny",
wantHasResult: false,
wantAllow: false,
wantDeny: true,
wantErr: true,
},
{
name: "explicit-deny",
res: DenyAccess(errNotAllowed),
wantStr: "Deny: " + errNotAllowed.Error(),
wantHasResult: true,
wantAllow: false,
wantDeny: true,
wantErr: true,
},
{
name: "explicit-allow",
res: AllowAccess(),
wantStr: "Allow",
wantHasResult: true,
wantAllow: true,
wantDeny: false,
wantErr: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if gotStr := tt.res.String(); gotStr != tt.wantStr {
t.Errorf("got: %q, want: %q", gotStr, tt.wantStr)
}
if gotHasResult := tt.res.HasResult(); gotHasResult != tt.wantHasResult {
t.Errorf("gotHasResult: %v, wantHasResult: %v", gotHasResult, tt.wantHasResult)
}
if gotAllow := tt.res.Allowed(); gotAllow != tt.wantAllow {
t.Errorf("gotAllow: %v, wantAllow: %v", gotAllow, tt.wantAllow)
}
if gotDeny := tt.res.Denied(); gotDeny != tt.wantDeny {
t.Errorf("gotDeny: %v, wantDeny: %v", gotDeny, tt.wantDeny)
}
if gotErr := tt.res.Error(); tt.wantErr {
if _, isAccessDenied := gotErr.(*ipn.AccessDeniedError); !isAccessDenied {
t.Errorf("err: %v, wantErr: %v", gotErr, tt.wantErr)
}
} else if gotErr != nil {
t.Errorf("err: %v, wantErr: %v", gotErr, tt.wantErr)
}
})
}
}
func TestAccessCheckerGrant(t *testing.T) {
tests := []struct {
name string
requested ProfileAccess
grant []ProfileAccess
wantRemaining ProfileAccess
wantHasResult bool
wantAllow bool
wantDeny bool
}{
{
name: "grant-none",
requested: ReadProfileInfo,
grant: []ProfileAccess{},
wantRemaining: ReadProfileInfo,
wantHasResult: false,
wantAllow: false,
wantDeny: true,
},
{
name: "grant-single",
requested: ReadProfileInfo,
grant: []ProfileAccess{ReadProfileInfo},
wantRemaining: 0,
wantHasResult: true,
wantAllow: true,
wantDeny: false,
},
{
name: "grant-other",
requested: ReadProfileInfo,
grant: []ProfileAccess{Connect},
wantRemaining: ReadProfileInfo,
wantHasResult: false,
wantAllow: false,
wantDeny: true,
},
{
name: "grant-some",
requested: ReadProfileInfo | Connect,
grant: []ProfileAccess{ReadProfileInfo},
wantRemaining: Connect,
wantHasResult: false,
wantAllow: false,
wantDeny: true,
},
{
name: "grant-all",
requested: ReadProfileInfo | Connect | Disconnect | ReadPrefs,
grant: []ProfileAccess{ReadProfileInfo, Connect | Disconnect, ReadPrefs},
wantRemaining: 0,
wantHasResult: true,
wantAllow: true,
wantDeny: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
checker := newAccessChecker(tt.requested)
for _, grant := range tt.grant {
checker.grant(grant)
}
if gotRemaining := checker.remaining(); gotRemaining != tt.wantRemaining {
t.Errorf("gotRemaining: %v, wantRemaining: %v", gotRemaining, tt.wantRemaining)
}
res := checker.result()
if gotHasResult := res.HasResult(); gotHasResult != tt.wantHasResult {
t.Errorf("gotHasResult: %v, wantHasResult: %v", gotHasResult, tt.wantHasResult)
}
if gotAllow := res.Allowed(); gotAllow != tt.wantAllow {
t.Errorf("gotAllow: %v, wantAllow: %v", gotAllow, tt.wantAllow)
}
if gotDeny := res.Denied(); gotDeny != tt.wantDeny {
t.Errorf("gotDeny: %v, wantDeny: %v", gotDeny, tt.wantDeny)
}
})
}
}
func TestAccessCheckerConditionalGrant(t *testing.T) {
tests := []struct {
name string
requested ProfileAccess
mustGrant bool
grant ProfileAccess
predicate func() error
wantRemaining ProfileAccess
wantHasResult bool
wantAllow bool
wantDeny bool
}{
{
name: "try-grant",
requested: ReadProfileInfo,
grant: ReadProfileInfo,
predicate: func() error { return nil },
wantRemaining: 0,
wantHasResult: true,
wantAllow: true,
wantDeny: false,
},
{
name: "try-grant-err",
requested: ReadProfileInfo,
grant: ReadProfileInfo,
predicate: func() error { return errNotAllowed },
wantRemaining: ReadProfileInfo,
wantHasResult: false,
wantAllow: false,
wantDeny: true,
},
{
name: "must-grant",
requested: ReadProfileInfo,
mustGrant: true,
grant: ReadProfileInfo,
predicate: func() error { return nil },
wantRemaining: 0,
wantHasResult: true,
wantAllow: true,
wantDeny: false,
},
{
name: "must-grant-err",
requested: ReadProfileInfo,
mustGrant: true,
grant: ReadProfileInfo,
predicate: func() error { return errNotAllowed },
wantRemaining: ReadProfileInfo,
wantHasResult: true,
wantAllow: false,
wantDeny: true,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
checker := newAccessChecker(tt.requested)
var res AccessCheckResult
if tt.mustGrant {
res = checker.mustGrant(tt.grant, tt.predicate)
} else {
res = checker.tryGrant(tt.grant, tt.predicate)
}
if gotRemaining := checker.remaining(); gotRemaining != tt.wantRemaining {
t.Errorf("gotRemaining: %v, wantRemaining: %v", gotRemaining, tt.wantRemaining)
}
if gotHasResult := res.HasResult(); gotHasResult != tt.wantHasResult {
t.Errorf("gotHasResult: %v, wantHasResult: %v", gotHasResult, tt.wantHasResult)
}
if gotAllow := res.Allowed(); gotAllow != tt.wantAllow {
t.Errorf("gotAllow: %v, wantAllow: %v", gotAllow, tt.wantAllow)
}
if gotDeny := res.Denied(); gotDeny != tt.wantDeny {
t.Errorf("gotDeny: %v, wantDeny: %v", gotDeny, tt.wantDeny)
}
})
}
}
func TestAccessCheckerDeny(t *testing.T) {
tests := []struct {
name string
requested ProfileAccess
grant ProfileAccess
deny ProfileAccess
wantHasResult bool
wantAllow bool
wantDeny bool
}{
{
name: "deny-single",
requested: ReadProfileInfo,
deny: ReadProfileInfo,
wantHasResult: true,
wantAllow: false,
wantDeny: true,
},
{
name: "deny-other",
requested: ReadProfileInfo,
deny: Connect,
wantHasResult: false,
wantAllow: false,
wantDeny: true,
},
{
name: "grant-some-then-deny",
requested: ReadProfileInfo | Connect,
grant: ReadProfileInfo,
deny: Connect,
wantHasResult: true,
wantAllow: false,
wantDeny: true,
},
{
name: "deny-some",
requested: ReadProfileInfo | Connect | Disconnect | ReadPrefs,
deny: Connect,
wantHasResult: true,
wantAllow: false,
wantDeny: true,
},
{
name: "deny-all",
requested: ReadProfileInfo | Connect | Disconnect | ReadPrefs,
deny: ReadProfileInfo | Connect | Disconnect | ReadPrefs,
wantHasResult: true,
wantAllow: false,
wantDeny: true,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
checker := newAccessChecker(tt.requested)
res := checker.grant(tt.grant)
if res.HasResult() {
t.Fatalf("the result must not be ready yet")
}
res = checker.deny(tt.deny, errNotAllowed)
if gotHasResult := res.HasResult(); gotHasResult != tt.wantHasResult {
t.Errorf("gotHasResult: %v, wantHasResult: %v", gotHasResult, tt.wantHasResult)
}
if gotAllow := res.Allowed(); gotAllow != tt.wantAllow {
t.Errorf("gotAllow: %v, wantAllow: %v", gotAllow, tt.wantAllow)
}
if gotDeny := res.Denied(); gotDeny != tt.wantDeny {
t.Errorf("gotDeny: %v, wantDeny: %v", gotDeny, tt.wantDeny)
}
})
}
}
func TestFilterProfile(t *testing.T) {
profile := &ipn.LoginProfile{
ID: "TEST",
Key: "profile-TEST",
Name: "user@example.com",
NetworkProfile: ipn.NetworkProfile{
MagicDNSName: "example.ts.net",
DomainName: "example.ts.net",
},
UserProfile: tailcfg.UserProfile{
ID: 123456789,
LoginName: "user@example.com",
DisplayName: "User",
ProfilePicURL: "https://example.com/profile.png",
},
NodeID: "TEST-NODE-ID",
LocalUserID: "S-1-5-21-1234567890-1234567890-1234567890-1001",
ControlURL: "https://controlplane.tailscale.com",
}
tests := []struct {
name string
user Identity
profile *ipn.LoginProfile
wantProfile *ipn.LoginProfile
}{
{
name: "filter-unreadable",
user: &TestIdentity{ProfileAccess: 0},
profile: profile,
wantProfile: &ipn.LoginProfile{
ID: profile.ID,
Name: "Other User's Account",
Key: profile.Key,
LocalUserID: profile.LocalUserID,
UserProfile: tailcfg.UserProfile{
LoginName: "Other User's Account",
DisplayName: "Other User",
},
},
},
{
name: "do-not-filter-readable",
user: &TestIdentity{UID: string(profile.LocalUserID), ProfileAccess: ReadProfileInfo},
profile: profile,
wantProfile: profile,
},
{
name: "do-not-filter-for-self",
user: Self,
profile: profile,
wantProfile: profile,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
profile := FilterProfile(tt.user, tt.profile.View(), ipn.PrefsGetterFor(ipn.PrefsView{})).AsStruct()
if !reflect.DeepEqual(profile, tt.wantProfile) {
t.Errorf("got: %+v, want: %+v", profile, tt.wantProfile)
}
})
}
}
func TestPrefsChangeRequiredAccess(t *testing.T) {
tests := []struct {
name string
prefs ipn.MaskedPrefs
wantRequiredAccess ProfileAccess
}{
{
name: "no-changes",
prefs: ipn.MaskedPrefs{},
wantRequiredAccess: 0,
},
{
name: "connect",
prefs: ipn.MaskedPrefs{
Prefs: ipn.Prefs{WantRunning: true},
WantRunningSet: true,
},
wantRequiredAccess: Connect,
},
{
name: "disconnect",
prefs: ipn.MaskedPrefs{
Prefs: ipn.Prefs{WantRunning: false},
WantRunningSet: true,
},
wantRequiredAccess: Disconnect,
},
{
name: "change-exit-node-id",
prefs: ipn.MaskedPrefs{
ExitNodeIDSet: true,
},
wantRequiredAccess: ChangeExitNode,
},
{
name: "change-exit-node-ip",
prefs: ipn.MaskedPrefs{
ExitNodeIPSet: true,
},
wantRequiredAccess: ChangeExitNode,
},
{
name: "change-exit-node-lan-access",
prefs: ipn.MaskedPrefs{
ExitNodeAllowLANAccessSet: true,
},
wantRequiredAccess: ChangeExitNode,
},
{
name: "change-multiple",
prefs: ipn.MaskedPrefs{
Prefs: ipn.Prefs{WantRunning: true},
ExitNodeIDSet: true,
WantRunningSet: true,
},
wantRequiredAccess: Connect | ChangeExitNode,
},
{
name: "change-other-single",
prefs: ipn.MaskedPrefs{
ForceDaemonSet: true,
},
wantRequiredAccess: ChangePrefs,
},
{
name: "change-other-multiple",
prefs: ipn.MaskedPrefs{
ForceDaemonSet: true,
RunSSHSet: true,
},
wantRequiredAccess: ChangePrefs,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
gotRequiredAccess := PrefsChangeRequiredAccess(&tt.prefs)
if gotRequiredAccess != tt.wantRequiredAccess {
t.Errorf("got: %v, want: %v", gotRequiredAccess, tt.wantRequiredAccess)
}
})
}
}
func TestCheckEditProfile(t *testing.T) {
tests := []struct {
name string
prefs ipn.MaskedPrefs
user Identity
wantAllow bool
}{
{
name: "allow-connect",
prefs: ipn.MaskedPrefs{
Prefs: ipn.Prefs{WantRunning: true},
WantRunningSet: true,
},
user: &TestIdentity{ProfileAccess: Connect},
wantAllow: true,
},
{
name: "deny-connect",
prefs: ipn.MaskedPrefs{
Prefs: ipn.Prefs{WantRunning: true},
WantRunningSet: true,
},
user: &TestIdentity{ProfileAccess: ReadProfileInfo},
wantAllow: false,
},
{
name: "allow-change-exit-node",
prefs: ipn.MaskedPrefs{
ExitNodeIDSet: true,
},
user: &TestIdentity{ProfileAccess: ChangeExitNode},
wantAllow: true,
},
{
name: "allow-change-prefs",
prefs: ipn.MaskedPrefs{
ForceDaemonSet: true,
RunSSHSet: true,
},
user: &TestIdentity{ProfileAccess: ChangePrefs},
wantAllow: true,
},
{
name: "deny-change-prefs",
prefs: ipn.MaskedPrefs{
ForceDaemonSet: true,
RunSSHSet: true,
},
user: &TestIdentity{ProfileAccess: ChangeExitNode},
wantAllow: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
profile, prefs := ipn.LoginProfile{}, ipn.NewPrefs()
res := CheckEditProfile(tt.user, profile.View(), ipn.PrefsGetterFor(prefs.View()), &tt.prefs)
if gotAllow := res.Allowed(); gotAllow != tt.wantAllow {
t.Errorf("gotAllow: %v, wantAllow: %v", gotAllow, tt.wantAllow)
}
})
}
}
func TestDenyAccessWithNilError(t *testing.T) {
res := DenyAccess(nil)
if gotHasResult := res.HasResult(); !gotHasResult {
t.Errorf("gotHasResult: %v, wantHasResult: true", gotHasResult)
}
if gotAllow := res.Allowed(); gotAllow {
t.Errorf("gotAllow: %v, wantAllow: false", gotAllow)
}
if gotDeny := res.Denied(); !gotDeny {
t.Errorf("gotDeny: %v, wantDeny: true", gotDeny)
}
gotErr := res.Error()
if _, isInternalError := gotErr.(*ipn.InternalServerError); !isInternalError {
t.Errorf("got %T: %v, want: *ipn.InternalServerError", gotErr, gotErr)
}
}