go1.16 (#14783)

vendor/github.com/Microsoft/go-winio/privilege.go

@@ -0,0 +1,202 @@
+// +build windows
+
+package winio
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"runtime"
+	"sync"
+	"syscall"
+	"unicode/utf16"
+
+	"golang.org/x/sys/windows"
+)
+
+//sys adjustTokenPrivileges(token windows.Token, releaseAll bool, input *byte, outputSize uint32, output *byte, requiredSize *uint32) (success bool, err error) [true] = advapi32.AdjustTokenPrivileges
+//sys impersonateSelf(level uint32) (err error) = advapi32.ImpersonateSelf
+//sys revertToSelf() (err error) = advapi32.RevertToSelf
+//sys openThreadToken(thread syscall.Handle, accessMask uint32, openAsSelf bool, token *windows.Token) (err error) = advapi32.OpenThreadToken
+//sys getCurrentThread() (h syscall.Handle) = GetCurrentThread
+//sys lookupPrivilegeValue(systemName string, name string, luid *uint64) (err error) = advapi32.LookupPrivilegeValueW
+//sys lookupPrivilegeName(systemName string, luid *uint64, buffer *uint16, size *uint32) (err error) = advapi32.LookupPrivilegeNameW
+//sys lookupPrivilegeDisplayName(systemName string, name *uint16, buffer *uint16, size *uint32, languageId *uint32) (err error) = advapi32.LookupPrivilegeDisplayNameW
+
+const (
+	SE_PRIVILEGE_ENABLED = 2
+
+	ERROR_NOT_ALL_ASSIGNED syscall.Errno = 1300
+
+	SeBackupPrivilege  = "SeBackupPrivilege"
+	SeRestorePrivilege = "SeRestorePrivilege"
+)
+
+const (
+	securityAnonymous = iota
+	securityIdentification
+	securityImpersonation
+	securityDelegation
+)
+
+var (
+	privNames     = make(map[string]uint64)
+	privNameMutex sync.Mutex
+)
+
+// PrivilegeError represents an error enabling privileges.
+type PrivilegeError struct {
+	privileges []uint64
+}
+
+func (e *PrivilegeError) Error() string {
+	s := ""
+	if len(e.privileges) > 1 {
+		s = "Could not enable privileges "
+	} else {
+		s = "Could not enable privilege "
+	}
+	for i, p := range e.privileges {
+		if i != 0 {
+			s += ", "
+		}
+		s += `"`
+		s += getPrivilegeName(p)
+		s += `"`
+	}
+	return s
+}
+
+// RunWithPrivilege enables a single privilege for a function call.
+func RunWithPrivilege(name string, fn func() error) error {
+	return RunWithPrivileges([]string{name}, fn)
+}
+
+// RunWithPrivileges enables privileges for a function call.
+func RunWithPrivileges(names []string, fn func() error) error {
+	privileges, err := mapPrivileges(names)
+	if err != nil {
+		return err
+	}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	token, err := newThreadToken()
+	if err != nil {
+		return err
+	}
+	defer releaseThreadToken(token)
+	err = adjustPrivileges(token, privileges, SE_PRIVILEGE_ENABLED)
+	if err != nil {
+		return err
+	}
+	return fn()
+}
+
+func mapPrivileges(names []string) ([]uint64, error) {
+	var privileges []uint64
+	privNameMutex.Lock()
+	defer privNameMutex.Unlock()
+	for _, name := range names {
+		p, ok := privNames[name]
+		if !ok {
+			err := lookupPrivilegeValue("", name, &p)
+			if err != nil {
+				return nil, err
+			}
+			privNames[name] = p
+		}
+		privileges = append(privileges, p)
+	}
+	return privileges, nil
+}
+
+// EnableProcessPrivileges enables privileges globally for the process.
+func EnableProcessPrivileges(names []string) error {
+	return enableDisableProcessPrivilege(names, SE_PRIVILEGE_ENABLED)
+}
+
+// DisableProcessPrivileges disables privileges globally for the process.
+func DisableProcessPrivileges(names []string) error {
+	return enableDisableProcessPrivilege(names, 0)
+}
+
+func enableDisableProcessPrivilege(names []string, action uint32) error {
+	privileges, err := mapPrivileges(names)
+	if err != nil {
+		return err
+	}
+
+	p, _ := windows.GetCurrentProcess()
+	var token windows.Token
+	err = windows.OpenProcessToken(p, windows.TOKEN_ADJUST_PRIVILEGES|windows.TOKEN_QUERY, &token)
+	if err != nil {
+		return err
+	}
+
+	defer token.Close()
+	return adjustPrivileges(token, privileges, action)
+}
+
+func adjustPrivileges(token windows.Token, privileges []uint64, action uint32) error {
+	var b bytes.Buffer
+	binary.Write(&b, binary.LittleEndian, uint32(len(privileges)))
+	for _, p := range privileges {
+		binary.Write(&b, binary.LittleEndian, p)
+		binary.Write(&b, binary.LittleEndian, action)
+	}
+	prevState := make([]byte, b.Len())
+	reqSize := uint32(0)
+	success, err := adjustTokenPrivileges(token, false, &b.Bytes()[0], uint32(len(prevState)), &prevState[0], &reqSize)
+	if !success {
+		return err
+	}
+	if err == ERROR_NOT_ALL_ASSIGNED {
+		return &PrivilegeError{privileges}
+	}
+	return nil
+}
+
+func getPrivilegeName(luid uint64) string {
+	var nameBuffer [256]uint16
+	bufSize := uint32(len(nameBuffer))
+	err := lookupPrivilegeName("", &luid, &nameBuffer[0], &bufSize)
+	if err != nil {
+		return fmt.Sprintf("<unknown privilege %d>", luid)
+	}
+
+	var displayNameBuffer [256]uint16
+	displayBufSize := uint32(len(displayNameBuffer))
+	var langID uint32
+	err = lookupPrivilegeDisplayName("", &nameBuffer[0], &displayNameBuffer[0], &displayBufSize, &langID)
+	if err != nil {
+		return fmt.Sprintf("<unknown privilege %s>", string(utf16.Decode(nameBuffer[:bufSize])))
+	}
+
+	return string(utf16.Decode(displayNameBuffer[:displayBufSize]))
+}
+
+func newThreadToken() (windows.Token, error) {
+	err := impersonateSelf(securityImpersonation)
+	if err != nil {
+		return 0, err
+	}
+
+	var token windows.Token
+	err = openThreadToken(getCurrentThread(), syscall.TOKEN_ADJUST_PRIVILEGES|syscall.TOKEN_QUERY, false, &token)
+	if err != nil {
+		rerr := revertToSelf()
+		if rerr != nil {
+			panic(rerr)
+		}
+		return 0, err
+	}
+	return token, nil
+}
+
+func releaseThreadToken(h windows.Token) {
+	err := revertToSelf()
+	if err != nil {
+		panic(err)
+	}
+	h.Close()
+}