1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package pe implements access to PE (Microsoft Windows Portable Executable) files.
package pe
import (
"debug/dwarf"
"encoding/binary"
"errors"
"fmt"
"io"
"os"
"strconv"
)
// A File represents an open PE file.
type File struct {
FileHeader
OptionalHeader interface{} // of type *OptionalHeader32 or *OptionalHeader64
Sections []*Section
Symbols []*Symbol
closer io.Closer
}
type SectionHeader struct {
Name string
VirtualSize uint32
VirtualAddress uint32
Size uint32
Offset uint32
PointerToRelocations uint32
PointerToLineNumbers uint32
NumberOfRelocations uint16
NumberOfLineNumbers uint16
Characteristics uint32
}
type Section struct {
SectionHeader
// Embed ReaderAt for ReadAt method.
// Do not embed SectionReader directly
// to avoid having Read and Seek.
// If a client wants Read and Seek it must use
// Open() to avoid fighting over the seek offset
// with other clients.
io.ReaderAt
sr *io.SectionReader
}
type Symbol struct {
Name string
Value uint32
SectionNumber int16
Type uint16
StorageClass uint8
}
type ImportDirectory struct {
OriginalFirstThunk uint32
TimeDateStamp uint32
ForwarderChain uint32
Name uint32
FirstThunk uint32
dll string
}
// Data reads and returns the contents of the PE section.
func (s *Section) Data() ([]byte, error) {
dat := make([]byte, s.sr.Size())
n, err := s.sr.ReadAt(dat, 0)
if n == len(dat) {
err = nil
}
return dat[0:n], err
}
// Open returns a new ReadSeeker reading the PE section.
func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
type FormatError struct {
off int64
msg string
val interface{}
}
func (e *FormatError) Error() string {
msg := e.msg
if e.val != nil {
msg += fmt.Sprintf(" '%v'", e.val)
}
msg += fmt.Sprintf(" in record at byte %#x", e.off)
return msg
}
// Open opens the named file using os.Open and prepares it for use as a PE binary.
func Open(name string) (*File, error) {
f, err := os.Open(name)
if err != nil {
return nil, err
}
ff, err := NewFile(f)
if err != nil {
f.Close()
return nil, err
}
ff.closer = f
return ff, nil
}
// Close closes the File.
// If the File was created using NewFile directly instead of Open,
// Close has no effect.
func (f *File) Close() error {
var err error
if f.closer != nil {
err = f.closer.Close()
f.closer = nil
}
return err
}
var (
sizeofOptionalHeader32 = uint16(binary.Size(OptionalHeader32{}))
sizeofOptionalHeader64 = uint16(binary.Size(OptionalHeader64{}))
)
// NewFile creates a new File for accessing a PE binary in an underlying reader.
func NewFile(r io.ReaderAt) (*File, error) {
f := new(File)
sr := io.NewSectionReader(r, 0, 1<<63-1)
var dosheader [96]byte
if _, err := r.ReadAt(dosheader[0:], 0); err != nil {
return nil, err
}
var base int64
if dosheader[0] == 'M' && dosheader[1] == 'Z' {
signoff := int64(binary.LittleEndian.Uint32(dosheader[0x3c:]))
var sign [4]byte
r.ReadAt(sign[:], signoff)
if !(sign[0] == 'P' && sign[1] == 'E' && sign[2] == 0 && sign[3] == 0) {
return nil, errors.New("Invalid PE File Format.")
}
base = signoff + 4
} else {
base = int64(0)
}
sr.Seek(base, os.SEEK_SET)
if err := binary.Read(sr, binary.LittleEndian, &f.FileHeader); err != nil {
return nil, err
}
if f.FileHeader.Machine != IMAGE_FILE_MACHINE_UNKNOWN && f.FileHeader.Machine != IMAGE_FILE_MACHINE_AMD64 && f.FileHeader.Machine != IMAGE_FILE_MACHINE_I386 {
return nil, errors.New("Invalid PE File Format.")
}
var ss []byte
if f.FileHeader.NumberOfSymbols > 0 {
// Get COFF string table, which is located at the end of the COFF symbol table.
sr.Seek(int64(f.FileHeader.PointerToSymbolTable+COFFSymbolSize*f.FileHeader.NumberOfSymbols), os.SEEK_SET)
var l uint32
if err := binary.Read(sr, binary.LittleEndian, &l); err != nil {
return nil, err
}
ss = make([]byte, l)
if _, err := r.ReadAt(ss, int64(f.FileHeader.PointerToSymbolTable+COFFSymbolSize*f.FileHeader.NumberOfSymbols)); err != nil {
return nil, err
}
// Process COFF symbol table.
sr.Seek(int64(f.FileHeader.PointerToSymbolTable), os.SEEK_SET)
aux := uint8(0)
for i := 0; i < int(f.FileHeader.NumberOfSymbols); i++ {
cs := new(COFFSymbol)
if err := binary.Read(sr, binary.LittleEndian, cs); err != nil {
return nil, err
}
if aux > 0 {
aux--
continue
}
var name string
if cs.Name[0] == 0 && cs.Name[1] == 0 && cs.Name[2] == 0 && cs.Name[3] == 0 {
si := int(binary.LittleEndian.Uint32(cs.Name[4:]))
name, _ = getString(ss, si)
} else {
name = cstring(cs.Name[:])
}
aux = cs.NumberOfAuxSymbols
s := &Symbol{
Name: name,
Value: cs.Value,
SectionNumber: cs.SectionNumber,
Type: cs.Type,
StorageClass: cs.StorageClass,
}
f.Symbols = append(f.Symbols, s)
}
}
// Read optional header.
sr.Seek(base, os.SEEK_SET)
if err := binary.Read(sr, binary.LittleEndian, &f.FileHeader); err != nil {
return nil, err
}
var oh32 OptionalHeader32
var oh64 OptionalHeader64
switch f.FileHeader.SizeOfOptionalHeader {
case sizeofOptionalHeader32:
if err := binary.Read(sr, binary.LittleEndian, &oh32); err != nil {
return nil, err
}
if oh32.Magic != 0x10b { // PE32
return nil, fmt.Errorf("pe32 optional header has unexpected Magic of 0x%x", oh32.Magic)
}
f.OptionalHeader = &oh32
case sizeofOptionalHeader64:
if err := binary.Read(sr, binary.LittleEndian, &oh64); err != nil {
return nil, err
}
if oh64.Magic != 0x20b { // PE32+
return nil, fmt.Errorf("pe32+ optional header has unexpected Magic of 0x%x", oh64.Magic)
}
f.OptionalHeader = &oh64
}
// Process sections.
f.Sections = make([]*Section, f.FileHeader.NumberOfSections)
for i := 0; i < int(f.FileHeader.NumberOfSections); i++ {
sh := new(SectionHeader32)
if err := binary.Read(sr, binary.LittleEndian, sh); err != nil {
return nil, err
}
var name string
if sh.Name[0] == '\x2F' {
si, _ := strconv.Atoi(cstring(sh.Name[1:]))
name, _ = getString(ss, si)
} else {
name = cstring(sh.Name[0:])
}
s := new(Section)
s.SectionHeader = SectionHeader{
Name: name,
VirtualSize: sh.VirtualSize,
VirtualAddress: sh.VirtualAddress,
Size: sh.SizeOfRawData,
Offset: sh.PointerToRawData,
PointerToRelocations: sh.PointerToRelocations,
PointerToLineNumbers: sh.PointerToLineNumbers,
NumberOfRelocations: sh.NumberOfRelocations,
NumberOfLineNumbers: sh.NumberOfLineNumbers,
Characteristics: sh.Characteristics,
}
s.sr = io.NewSectionReader(r, int64(s.SectionHeader.Offset), int64(s.SectionHeader.Size))
s.ReaderAt = s.sr
f.Sections[i] = s
}
return f, nil
}
func cstring(b []byte) string {
var i int
for i = 0; i < len(b) && b[i] != 0; i++ {
}
return string(b[0:i])
}
// getString extracts a string from symbol string table.
func getString(section []byte, start int) (string, bool) {
if start < 0 || start >= len(section) {
return "", false
}
for end := start; end < len(section); end++ {
if section[end] == 0 {
return string(section[start:end]), true
}
}
return "", false
}
// Section returns the first section with the given name, or nil if no such
// section exists.
func (f *File) Section(name string) *Section {
for _, s := range f.Sections {
if s.Name == name {
return s
}
}
return nil
}
func (f *File) DWARF() (*dwarf.Data, error) {
// There are many other DWARF sections, but these
// are the required ones, and the debug/dwarf package
// does not use the others, so don't bother loading them.
var names = [...]string{"abbrev", "info", "str"}
var dat [len(names)][]byte
for i, name := range names {
name = ".debug_" + name
s := f.Section(name)
if s == nil {
continue
}
b, err := s.Data()
if err != nil && uint32(len(b)) < s.Size {
return nil, err
}
dat[i] = b
}
abbrev, info, str := dat[0], dat[1], dat[2]
return dwarf.New(abbrev, nil, nil, info, nil, nil, nil, str)
}
// ImportedSymbols returns the names of all symbols
// referred to by the binary f that are expected to be
// satisfied by other libraries at dynamic load time.
// It does not return weak symbols.
func (f *File) ImportedSymbols() ([]string, error) {
pe64 := f.Machine == IMAGE_FILE_MACHINE_AMD64
ds := f.Section(".idata")
if ds == nil {
// not dynamic, so no libraries
return nil, nil
}
d, err := ds.Data()
if err != nil {
return nil, err
}
var ida []ImportDirectory
for len(d) > 0 {
var dt ImportDirectory
dt.OriginalFirstThunk = binary.LittleEndian.Uint32(d[0:4])
dt.Name = binary.LittleEndian.Uint32(d[12:16])
dt.FirstThunk = binary.LittleEndian.Uint32(d[16:20])
d = d[20:]
if dt.OriginalFirstThunk == 0 {
break
}
ida = append(ida, dt)
}
names, _ := ds.Data()
var all []string
for _, dt := range ida {
dt.dll, _ = getString(names, int(dt.Name-ds.VirtualAddress))
d, _ = ds.Data()
// seek to OriginalFirstThunk
d = d[dt.OriginalFirstThunk-ds.VirtualAddress:]
for len(d) > 0 {
if pe64 { // 64bit
va := binary.LittleEndian.Uint64(d[0:8])
d = d[8:]
if va == 0 {
break
}
if va&0x8000000000000000 > 0 { // is Ordinal
// TODO add dynimport ordinal support.
} else {
fn, _ := getString(names, int(uint32(va)-ds.VirtualAddress+2))
all = append(all, fn+":"+dt.dll)
}
} else { // 32bit
va := binary.LittleEndian.Uint32(d[0:4])
d = d[4:]
if va == 0 {
break
}
if va&0x80000000 > 0 { // is Ordinal
// TODO add dynimport ordinal support.
//ord := va&0x0000FFFF
} else {
fn, _ := getString(names, int(va-ds.VirtualAddress+2))
all = append(all, fn+":"+dt.dll)
}
}
}
}
return all, nil
}
// ImportedLibraries returns the names of all libraries
// referred to by the binary f that are expected to be
// linked with the binary at dynamic link time.
func (f *File) ImportedLibraries() ([]string, error) {
// TODO
// cgo -dynimport don't use this for windows PE, so just return.
return nil, nil
}
|