Files
netbird/client/ssh/server/privileges_windows_test.go

294 lines
10 KiB
Go

//go:build windows
package server
import (
"os/user"
"testing"
"unsafe"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"golang.org/x/sys/windows"
)
// filterNormalAccount limits NetUserEnum to normal user accounts.
const filterNormalAccount = 0x2
// TOKEN_ELEVATION_TYPE values.
const (
tokenElevationTypeDefault = 1
tokenElevationTypeFull = 2
tokenElevationTypeLimited = 3
)
// tokenElevationType reads TokenElevationType from a token.
func tokenElevationType(token windows.Token) (uint32, error) {
var elevationType, returnedLen uint32
err := windows.GetTokenInformation(token, windows.TokenElevationType,
(*byte)(unsafe.Pointer(&elevationType)), uint32(unsafe.Sizeof(elevationType)), &returnedLen)
if err != nil {
return 0, err
}
return elevationType, nil
}
// userInfo0 mirrors USER_INFO_0.
type userInfo0 struct {
name *uint16
}
func mustParseSID(t *testing.T, s string) *windows.SID {
t.Helper()
sid, err := windows.StringToSid(s)
require.NoError(t, err, "parse SID %s", s)
return sid
}
// localAccountNames returns the names of the local user accounts.
func localAccountNames(t *testing.T) []string {
t.Helper()
var buf *byte
var entriesRead, totalEntries, resume uint32
err := windows.NetUserEnum(nil, 0, filterNormalAccount, &buf, maxPreferredLength,
&entriesRead, &totalEntries, &resume)
require.NoError(t, err, "enumerate local users")
t.Cleanup(func() {
require.NoError(t, windows.NetApiBufferFree(buf), "free NetApi buffer")
})
entries := unsafe.Slice((*userInfo0)(unsafe.Pointer(buf)), entriesRead)
names := make([]string, 0, entriesRead)
for _, entry := range entries {
names = append(names, windows.UTF16PtrToString(entry.name))
}
return names
}
// localAccountNameByRID returns the name of the local account carrying the
// given RID. Accounts such as Administrator and Guest can be renamed and are
// localized, so tests must not name them literally.
func localAccountNameByRID(t *testing.T, rid uint32) string {
t.Helper()
for _, name := range localAccountNames(t) {
sid, _, _, err := windows.LookupSID("", name)
if err != nil {
continue
}
if sid.IdentifierAuthority() != windows.SECURITY_NT_AUTHORITY {
continue
}
count := sid.SubAuthorityCount()
if count < 2 || sid.SubAuthority(0) != 21 {
continue
}
if sid.SubAuthority(uint32(count-1)) == rid {
return name
}
}
t.Fatalf("no local account with RID %d", rid)
return ""
}
// wellKnownAccountName resolves a well-known SID to the qualified account name
// the local system uses for it, which is localized.
func wellKnownAccountName(t *testing.T, sidType windows.WELL_KNOWN_SID_TYPE) string {
t.Helper()
sid, err := windows.CreateWellKnownSid(sidType)
require.NoError(t, err, "create well-known SID")
name, domain, _, err := sid.LookupAccount("")
require.NoError(t, err, "resolve %s to an account name", sid)
if domain == "" {
return name
}
return domain + `\` + name
}
func TestIsBuiltinAdministratorSID(t *testing.T) {
tests := []struct {
name string
sid string
want bool
}{
{"machine_administrator", "S-1-5-21-1111111111-2222222222-3333333333-500", true},
{"domain_administrator", "S-1-5-21-3390233681-4087452608-412898826-500", true},
{"regular_user", "S-1-5-21-1111111111-2222222222-3333333333-1001", false},
{"guest_account", "S-1-5-21-1111111111-2222222222-3333333333-501", false},
{"domain_admins_group", "S-1-5-21-1111111111-2222222222-3333333333-512", false},
{"system", "S-1-5-18", false},
{"administrators_group", "S-1-5-32-544", false},
{"non_nt_authority", "S-1-1-0", false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := isBuiltinAdministratorSID(mustParseSID(t, tt.sid))
assert.Equal(t, tt.want, result, "RID 500 detection for %s", tt.sid)
})
}
}
func TestIsPrivilegedUserSID(t *testing.T) {
tests := []struct {
name string
sid string
want bool
}{
{"local_system", "S-1-5-18", true},
{"local_service", "S-1-5-19", true},
{"network_service", "S-1-5-20", true},
{"administrators_group", "S-1-5-32-544", true},
{"builtin_administrator", "S-1-5-21-1111111111-2222222222-3333333333-500", true},
{"regular_user", "S-1-5-21-1111111111-2222222222-3333333333-1001", false},
{"users_group", "S-1-5-32-545", false},
{"everyone", "S-1-1-0", false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := isPrivilegedUserSID(mustParseSID(t, tt.sid))
assert.Equal(t, tt.want, result, "SID privilege classification for %s", tt.sid)
})
}
}
func TestIsWindowsAccountPrivileged(t *testing.T) {
tests := []struct {
name string
username string
want bool
}{
{"system", wellKnownAccountName(t, windows.WinLocalSystemSid), true},
{"local_service", wellKnownAccountName(t, windows.WinLocalServiceSid), true},
{"network_service", wellKnownAccountName(t, windows.WinNetworkServiceSid), true},
{"administrators_group", wellKnownAccountName(t, windows.WinBuiltinAdministratorsSid), true},
// The built-in Administrator (RID 500) and Guest (RID 501) accounts
// exist on every Windows installation, though they may be disabled.
{"builtin_administrator", localAccountNameByRID(t, 500), true},
{"guest", localAccountNameByRID(t, 501), false},
// Unresolvable accounts fail closed.
{"nonexistent_user", "netbird-no-such-user", true},
{"empty_username", "", true},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := isWindowsAccountPrivileged(tt.username)
assert.Equal(t, tt.want, result, "account privilege classification for %q", tt.username)
})
}
}
func TestIsProcessElevated(t *testing.T) {
elevated := isProcessElevated()
// TokenElevationType is a second, independent view of the same token:
// Full means elevated and Limited means a filtered administrator, while
// Default covers both a standard user and an administrator with no linked
// token (UAC off, the built-in Administrator, SYSTEM), so it implies nothing.
elevationType, err := tokenElevationType(windows.GetCurrentProcessToken())
require.NoError(t, err, "read token elevation type")
adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
require.NoError(t, err, "create Administrators SID")
// Token(0) makes CheckTokenMembership evaluate the caller's own token. It
// counts only enabled SIDs, so a filtered administrator reports false here.
member, err := windows.Token(0).IsMember(adminSid)
require.NoError(t, err, "check own Administrators membership")
t.Logf("elevated=%v elevationType=%d memberOfAdministrators=%v", elevated, elevationType, member)
switch elevationType {
case tokenElevationTypeFull:
assert.True(t, elevated, "a token of elevation type Full must report elevated")
case tokenElevationTypeLimited:
assert.False(t, elevated, "a filtered administrator token must not report elevated")
}
// Administrators enabled in the token means the token wields administrative
// rights, which is what elevation reports.
if member {
assert.True(t, elevated, "token with enabled Administrators membership must report elevated")
}
}
// TestS4UMembershipAgreesWithLocalGroups exercises the S4U token path used
// for domain accounts. S4U logons need the TCB privilege, so the test runs
// only as SYSTEM (which is how CI executes the suite). For local accounts the
// token's Administrators membership must agree with the SAM enumeration.
func TestS4UMembershipAgreesWithLocalGroups(t *testing.T) {
system, err := windows.CreateWellKnownSid(windows.WinLocalSystemSid)
require.NoError(t, err, "create SYSTEM SID")
current, err := user.Current()
require.NoError(t, err, "get current user")
if current.Uid != system.String() {
t.Skipf("S4U logon requires SYSTEM (running as %s)", current.Username)
}
adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
require.NoError(t, err, "create Administrators SID")
checked := 0
for _, name := range localAccountNames(t) {
viaToken, err := s4uTokenIsMember(name, ".", adminSid)
if err != nil {
// Disabled or logon-restricted accounts cannot get an S4U logon.
t.Logf("skipping %s: %v", name, err)
continue
}
viaSAM, err := localGroupsContainSID(name, adminSid)
require.NoError(t, err, "enumerate local groups for %s", name)
assert.Equal(t, viaSAM, viaToken, "S4U token and SAM enumeration must agree on Administrators membership for %s", name)
checked++
}
// Ineligible accounts are skipped, so without this the test could report
// success while comparing nothing at all.
require.Positive(t, checked, "no local account completed an S4U logon, so nothing was compared")
t.Logf("checked %d local accounts via S4U", checked)
}
// TestLocalGroupsContainSID_Administrator checks the positive case against the
// built-in Administrator, a member of Administrators on every installation.
func TestLocalGroupsContainSID_Administrator(t *testing.T) {
adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
require.NoError(t, err, "create Administrators SID")
administrator := localAccountNameByRID(t, 500)
member, err := localGroupsContainSID(administrator, adminSid)
require.NoError(t, err, "enumerate local groups for %s", administrator)
assert.True(t, member, "%s is a member of the Administrators group", administrator)
}
// TestLocalGroupsContainSID_UnresolvableGroupFailsClosed covers a wanted SID
// that resolves to no group: the error must surface rather than being reported
// as "not a member", so the privilege check treats the account as privileged.
func TestLocalGroupsContainSID_UnresolvableGroupFailsClosed(t *testing.T) {
unknown := mustParseSID(t, "S-1-5-21-1111111111-2222222222-3333333333-4444")
_, err := localGroupsContainSID(localAccountNameByRID(t, 500), unknown)
require.Error(t, err, "must report an error when the wanted group cannot be identified")
}
func TestLocalGroupsContainSID_Guest(t *testing.T) {
guestsSid, err := windows.CreateWellKnownSid(windows.WinBuiltinGuestsSid)
require.NoError(t, err, "create Guests SID")
adminsSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
require.NoError(t, err, "create Administrators SID")
guest := localAccountNameByRID(t, 501)
inGuests, err := localGroupsContainSID(guest, guestsSid)
require.NoError(t, err, "enumerate local groups for %s", guest)
assert.True(t, inGuests, "%s is a member of the Guests group", guest)
inAdmins, err := localGroupsContainSID(guest, adminsSid)
require.NoError(t, err, "enumerate local groups for %s", guest)
assert.False(t, inAdmins, "%s is not a member of the Administrators group", guest)
}