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Refactor extended attributes and security descriptor helpers to use go-winio (#5040)

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* Refactor ea and sd helpers to use go-winio

Import go-winio and instead of copying the functions to encode/decode extended attributes and enable process privileges for security descriptors, call the functions defined in go-winio.
This commit is contained in:
Aneesh N 2024-12-10 02:18:38 +05:30 committed by GitHub
parent d7d9af4c9f
commit 6808004ad1
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GPG key ID: B5690EEEBB952194
4 changed files with 23 additions and 389 deletions
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1
go.mod
View file

@ -6,6 +6,7 @@ require (
github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.8.0 github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.8.0
github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.5.0 github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.5.0
github.com/Backblaze/blazer v0.7.1 github.com/Backblaze/blazer v0.7.1
github.com/Microsoft/go-winio v0.6.2
github.com/anacrolix/fuse v0.3.1 github.com/anacrolix/fuse v0.3.1
github.com/cenkalti/backoff/v4 v4.3.0 github.com/cenkalti/backoff/v4 v4.3.0
github.com/cespare/xxhash/v2 v2.3.0 github.com/cespare/xxhash/v2 v2.3.0

2
go.sum
View file

@ -33,6 +33,8 @@ github.com/Backblaze/blazer v0.7.1 h1:J43PbFj6hXLg1jvCNr+rQoAsxzKK0IP7ftl1ReCwpc
github.com/Backblaze/blazer v0.7.1/go.mod h1:MhntL1nMpIuoqrPP6TnZu/xTydMgOAe/Xm6KongbjKs= github.com/Backblaze/blazer v0.7.1/go.mod h1:MhntL1nMpIuoqrPP6TnZu/xTydMgOAe/Xm6KongbjKs=
github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU= github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
github.com/Julusian/godocdown v0.0.0-20170816220326-6d19f8ff2df8/go.mod h1:INZr5t32rG59/5xeltqoCJoNY7e5x/3xoY9WSWVWg74= github.com/Julusian/godocdown v0.0.0-20170816220326-6d19f8ff2df8/go.mod h1:INZr5t32rG59/5xeltqoCJoNY7e5x/3xoY9WSWVWg74=
github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
github.com/anacrolix/envpprof v1.3.0 h1:WJt9bpuT7A/CDCxPOv/eeZqHWlle/Y0keJUvc6tcJDk= github.com/anacrolix/envpprof v1.3.0 h1:WJt9bpuT7A/CDCxPOv/eeZqHWlle/Y0keJUvc6tcJDk=
github.com/anacrolix/envpprof v1.3.0/go.mod h1:7QIG4CaX1uexQ3tqd5+BRa/9e2D02Wcertl6Yh0jCB0= github.com/anacrolix/envpprof v1.3.0/go.mod h1:7QIG4CaX1uexQ3tqd5+BRa/9e2D02Wcertl6Yh0jCB0=
github.com/anacrolix/fuse v0.3.1 h1:oT8s3B5HFkBdLe/WKJO5MNo9iIyEtc+BhvTZYp4jhDM= github.com/anacrolix/fuse v0.3.1 h1:oT8s3B5HFkBdLe/WKJO5MNo9iIyEtc+BhvTZYp4jhDM=

153
internal/fs/ea_windows.go
View file

@ -4,17 +4,28 @@
package fs package fs
import ( import (
"bytes"
"encoding/binary"
"errors"
"fmt" "fmt"
"syscall" "syscall"
"unsafe" "unsafe"
"github.com/Microsoft/go-winio"
"golang.org/x/sys/windows" "golang.org/x/sys/windows"
) )
// The code below was adapted from https://github.com/microsoft/go-winio under MIT license. // extendedAttribute is a type alias for winio.ExtendedAttribute
type extendedAttribute = winio.ExtendedAttribute
// encodeExtendedAttributes encodes the extended attributes to a byte slice.
func encodeExtendedAttributes(attrs []extendedAttribute) ([]byte, error) {
return winio.EncodeExtendedAttributes(attrs)
}
// decodeExtendedAttributes decodes the extended attributes from a byte slice.
func decodeExtendedAttributes(data []byte) ([]extendedAttribute, error) {
return winio.DecodeExtendedAttributes(data)
}
// The code below was copied over from https://github.com/microsoft/go-winio/blob/main/pipe.go under MIT license.
// The MIT License (MIT) // The MIT License (MIT)
@ -38,140 +49,6 @@ import (
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE. // SOFTWARE.
// The code below was copied over from https://github.com/microsoft/go-winio/blob/main/ea.go under MIT license.
type fileFullEaInformation struct {
NextEntryOffset uint32
Flags uint8
NameLength uint8
ValueLength uint16
}
var (
fileFullEaInformationSize = binary.Size(&fileFullEaInformation{})
errInvalidEaBuffer = errors.New("invalid extended attribute buffer")
errEaNameTooLarge = errors.New("extended attribute name too large")
errEaValueTooLarge = errors.New("extended attribute value too large")
)
// extendedAttribute represents a single Windows EA.
type extendedAttribute struct {
Name string
Value []byte
Flags uint8
}
func parseEa(b []byte) (ea extendedAttribute, nb []byte, err error) {
var info fileFullEaInformation
err = binary.Read(bytes.NewReader(b), binary.LittleEndian, &info)
if err != nil {
err = errInvalidEaBuffer
return ea, nb, err
}
nameOffset := fileFullEaInformationSize
nameLen := int(info.NameLength)
valueOffset := nameOffset + int(info.NameLength) + 1
valueLen := int(info.ValueLength)
nextOffset := int(info.NextEntryOffset)
if valueLen+valueOffset > len(b) || nextOffset < 0 || nextOffset > len(b) {
err = errInvalidEaBuffer
return ea, nb, err
}
ea.Name = string(b[nameOffset : nameOffset+nameLen])
ea.Value = b[valueOffset : valueOffset+valueLen]
ea.Flags = info.Flags
if info.NextEntryOffset != 0 {
nb = b[info.NextEntryOffset:]
}
return ea, nb, err
}
// decodeExtendedAttributes decodes a list of EAs from a FILE_FULL_EA_INFORMATION
// buffer retrieved from BackupRead, ZwQueryEaFile, etc.
func decodeExtendedAttributes(b []byte) (eas []extendedAttribute, err error) {
for len(b) != 0 {
ea, nb, err := parseEa(b)
if err != nil {
return nil, err
}
eas = append(eas, ea)
b = nb
}
return eas, err
}
func writeEa(buf *bytes.Buffer, ea *extendedAttribute, last bool) error {
if int(uint8(len(ea.Name))) != len(ea.Name) {
return errEaNameTooLarge
}
if int(uint16(len(ea.Value))) != len(ea.Value) {
return errEaValueTooLarge
}
entrySize := uint32(fileFullEaInformationSize + len(ea.Name) + 1 + len(ea.Value))
withPadding := (entrySize + 3) &^ 3
nextOffset := uint32(0)
if !last {
nextOffset = withPadding
}
info := fileFullEaInformation{
NextEntryOffset: nextOffset,
Flags: ea.Flags,
NameLength: uint8(len(ea.Name)),
ValueLength: uint16(len(ea.Value)),
}
err := binary.Write(buf, binary.LittleEndian, &info)
if err != nil {
return err
}
_, err = buf.Write([]byte(ea.Name))
if err != nil {
return err
}
err = buf.WriteByte(0)
if err != nil {
return err
}
_, err = buf.Write(ea.Value)
if err != nil {
return err
}
_, err = buf.Write([]byte{0, 0, 0}[0 : withPadding-entrySize])
if err != nil {
return err
}
return nil
}
// encodeExtendedAttributes encodes a list of EAs into a FILE_FULL_EA_INFORMATION
// buffer for use with BackupWrite, ZwSetEaFile, etc.
func encodeExtendedAttributes(eas []extendedAttribute) ([]byte, error) {
var buf bytes.Buffer
for i := range eas {
last := false
if i == len(eas)-1 {
last = true
}
err := writeEa(&buf, &eas[i], last)
if err != nil {
return nil, err
}
}
return buf.Bytes(), nil
}
// The code below was copied over from https://github.com/microsoft/go-winio/blob/main/pipe.go under MIT license.
type ntStatus int32 type ntStatus int32
func (status ntStatus) Err() error { func (status ntStatus) Err() error {

256
internal/fs/sd_windows.go
View file

@ -1,15 +1,13 @@
package fs package fs
import ( import (
"bytes"
"encoding/binary"
"fmt" "fmt"
"sync" "sync"
"sync/atomic" "sync/atomic"
"syscall" "syscall"
"unicode/utf16"
"unsafe" "unsafe"
"github.com/Microsoft/go-winio"
"github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/errors"
"golang.org/x/sys/windows" "golang.org/x/sys/windows"
@ -161,6 +159,10 @@ func setNamedSecurityInfoLow(filePath string, dacl *windows.ACL) error {
return windows.SetNamedSecurityInfo(fixpath(filePath), windows.SE_FILE_OBJECT, lowRestoreSecurityFlags, nil, nil, dacl, nil) return windows.SetNamedSecurityInfo(fixpath(filePath), windows.SE_FILE_OBJECT, lowRestoreSecurityFlags, nil, nil, dacl, nil)
} }
func enableProcessPrivileges(privileges []string) error {
return winio.EnableProcessPrivileges(privileges)
}
// enableBackupPrivilege enables privilege for backing up security descriptors // enableBackupPrivilege enables privilege for backing up security descriptors
func enableBackupPrivilege() { func enableBackupPrivilege() {
err := enableProcessPrivileges([]string{seBackupPrivilege}) err := enableProcessPrivileges([]string{seBackupPrivilege})
@ -212,251 +214,3 @@ func securityDescriptorStructToBytes(sd *windows.SECURITY_DESCRIPTOR) ([]byte, e
b := unsafe.Slice((*byte)(unsafe.Pointer(sd)), sd.Length()) b := unsafe.Slice((*byte)(unsafe.Pointer(sd)), sd.Length())
return b, nil return b, nil
} }
// The code below was adapted from
// https://github.com/microsoft/go-winio/blob/3c9576c9346a1892dee136329e7e15309e82fb4f/privilege.go
// under MIT license.
// The MIT License (MIT)
// Copyright (c) 2015 Microsoft
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
var (
modadvapi32 = windows.NewLazySystemDLL("advapi32.dll")
procLookupPrivilegeValueW = modadvapi32.NewProc("LookupPrivilegeValueW")
procAdjustTokenPrivileges = modadvapi32.NewProc("AdjustTokenPrivileges")
procLookupPrivilegeDisplayNameW = modadvapi32.NewProc("LookupPrivilegeDisplayNameW")
procLookupPrivilegeNameW = modadvapi32.NewProc("LookupPrivilegeNameW")
)
// Do the interface allocations only once for common
// Errno values.
const (
errnoErrorIOPending = 997
//revive:disable-next-line:var-naming ALL_CAPS
SE_PRIVILEGE_ENABLED = windows.SE_PRIVILEGE_ENABLED
//revive:disable-next-line:var-naming ALL_CAPS
ERROR_NOT_ALL_ASSIGNED windows.Errno = windows.ERROR_NOT_ALL_ASSIGNED
)
var (
errErrorIOPending error = syscall.Errno(errnoErrorIOPending)
errErrorEinval error = syscall.EINVAL
privNames = make(map[string]uint64)
privNameMutex sync.Mutex
)
// privilegeError represents an error enabling privileges.
type privilegeError struct {
privileges []uint64
}
// Error returns the string message for the error.
func (e *privilegeError) Error() string {
s := "Could not enable privilege "
if len(e.privileges) > 1 {
s = "Could not enable privileges "
}
for i, p := range e.privileges {
if i != 0 {
s += ", "
}
s += `"`
s += getPrivilegeName(p)
s += `"`
}
return s
}
func mapPrivileges(names []string) ([]uint64, error) {
privileges := make([]uint64, 0, len(names))
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)
}
func enableDisableProcessPrivilege(names []string, action uint32) error {
privileges, err := mapPrivileges(names)
if err != nil {
return err
}
p := windows.CurrentProcess()
var token windows.Token
err = windows.OpenProcessToken(p, windows.TOKEN_ADJUST_PRIVILEGES|windows.TOKEN_QUERY, &token)
if err != nil {
return err
}
defer func() {
_ = 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 { //nolint:errorlint // err is Errno
debug.Log("Not all requested privileges were fully set: %v. AdjustTokenPrivileges returned warning: %v", privileges, err)
}
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]))
}
// The functions below are copied over from https://github.com/microsoft/go-winio/blob/main/zsyscall_windows.go under MIT license.
// This windows api always returns an error even in case of success, warnings (partial success) and error cases.
//
// Full success - When we call this with admin permissions, it returns DNS_ERROR_RCODE_NO_ERROR (0).
// This gets translated to errErrorEinval and ultimately in adjustTokenPrivileges, it gets ignored.
//
// Partial success - If we call this api without admin privileges, privileges related to SACLs do not get set and
// though the api returns success, it returns an error - golang.org/x/sys/windows.ERROR_NOT_ALL_ASSIGNED (1300)
func adjustTokenPrivileges(token windows.Token, releaseAll bool, input *byte, outputSize uint32, output *byte, requiredSize *uint32) (success bool, err error) {
var _p0 uint32
if releaseAll {
_p0 = 1
}
r0, _, e1 := syscall.SyscallN(procAdjustTokenPrivileges.Addr(), uintptr(token), uintptr(_p0), uintptr(unsafe.Pointer(input)), uintptr(outputSize), uintptr(unsafe.Pointer(output)), uintptr(unsafe.Pointer(requiredSize)))
success = r0 != 0
if true {
err = errnoErr(e1)
}
return
}
func lookupPrivilegeDisplayName(systemName string, name *uint16, buffer *uint16, size *uint32, languageID *uint32) (err error) {
var _p0 *uint16
_p0, err = syscall.UTF16PtrFromString(systemName)
if err != nil {
return
}
return _lookupPrivilegeDisplayName(_p0, name, buffer, size, languageID)
}
func _lookupPrivilegeDisplayName(systemName *uint16, name *uint16, buffer *uint16, size *uint32, languageID *uint32) (err error) {
r1, _, e1 := syscall.SyscallN(procLookupPrivilegeDisplayNameW.Addr(), uintptr(unsafe.Pointer(systemName)), uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(buffer)), uintptr(unsafe.Pointer(size)), uintptr(unsafe.Pointer(languageID)))
if r1 == 0 {
err = errnoErr(e1)
}
return
}
func lookupPrivilegeName(systemName string, luid *uint64, buffer *uint16, size *uint32) (err error) {
var _p0 *uint16
_p0, err = syscall.UTF16PtrFromString(systemName)
if err != nil {
return
}
return _lookupPrivilegeName(_p0, luid, buffer, size)
}
func _lookupPrivilegeName(systemName *uint16, luid *uint64, buffer *uint16, size *uint32) (err error) {
r1, _, e1 := syscall.SyscallN(procLookupPrivilegeNameW.Addr(), uintptr(unsafe.Pointer(systemName)), uintptr(unsafe.Pointer(luid)), uintptr(unsafe.Pointer(buffer)), uintptr(unsafe.Pointer(size)))
if r1 == 0 {
err = errnoErr(e1)
}
return
}
func lookupPrivilegeValue(systemName string, name string, luid *uint64) (err error) {
var _p0 *uint16
_p0, err = syscall.UTF16PtrFromString(systemName)
if err != nil {
return
}
var _p1 *uint16
_p1, err = syscall.UTF16PtrFromString(name)
if err != nil {
return
}
return _lookupPrivilegeValue(_p0, _p1, luid)
}
func _lookupPrivilegeValue(systemName *uint16, name *uint16, luid *uint64) (err error) {
r1, _, e1 := syscall.SyscallN(procLookupPrivilegeValueW.Addr(), uintptr(unsafe.Pointer(systemName)), uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(luid)))
if r1 == 0 {
err = errnoErr(e1)
}
return
}
// The code below was copied from https://github.com/microsoft/go-winio/blob/main/tools/mkwinsyscall/mkwinsyscall.go under MIT license.
// errnoErr returns common boxed Errno values, to prevent
// allocations at runtime.
func errnoErr(e syscall.Errno) error {
switch e {
case 0:
return errErrorEinval
case errnoErrorIOPending:
return errErrorIOPending
}
return e
}