From 43a123c1ae6613b3efeed291fa552ecd909d3acf Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:23:18 +0200 Subject: Adding upstream version 1.20.14. Signed-off-by: Daniel Baumann --- src/debug/macho/file.go | 726 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 726 insertions(+) create mode 100644 src/debug/macho/file.go (limited to 'src/debug/macho/file.go') diff --git a/src/debug/macho/file.go b/src/debug/macho/file.go new file mode 100644 index 0000000..ecde25a --- /dev/null +++ b/src/debug/macho/file.go @@ -0,0 +1,726 @@ +// 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 macho implements access to Mach-O object files. + +# Security + +This package is not designed to be hardened against adversarial inputs, and is +outside the scope of https://go.dev/security/policy. In particular, only basic +validation is done when parsing object files. As such, care should be taken when +parsing untrusted inputs, as parsing malformed files may consume significant +resources, or cause panics. +*/ +package macho + +// High level access to low level data structures. + +import ( + "bytes" + "compress/zlib" + "debug/dwarf" + "encoding/binary" + "fmt" + "internal/saferio" + "io" + "os" + "strings" +) + +// A File represents an open Mach-O file. +type File struct { + FileHeader + ByteOrder binary.ByteOrder + Loads []Load + Sections []*Section + + Symtab *Symtab + Dysymtab *Dysymtab + + closer io.Closer +} + +// A Load represents any Mach-O load command. +type Load interface { + Raw() []byte +} + +// A LoadBytes is the uninterpreted bytes of a Mach-O load command. +type LoadBytes []byte + +func (b LoadBytes) Raw() []byte { return b } + +// A SegmentHeader is the header for a Mach-O 32-bit or 64-bit load segment command. +type SegmentHeader struct { + Cmd LoadCmd + Len uint32 + Name string + Addr uint64 + Memsz uint64 + Offset uint64 + Filesz uint64 + Maxprot uint32 + Prot uint32 + Nsect uint32 + Flag uint32 +} + +// A Segment represents a Mach-O 32-bit or 64-bit load segment command. +type Segment struct { + LoadBytes + SegmentHeader + + // 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 +} + +// Data reads and returns the contents of the segment. +func (s *Segment) Data() ([]byte, error) { + return saferio.ReadDataAt(s.sr, s.Filesz, 0) +} + +// Open returns a new ReadSeeker reading the segment. +func (s *Segment) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) } + +type SectionHeader struct { + Name string + Seg string + Addr uint64 + Size uint64 + Offset uint32 + Align uint32 + Reloff uint32 + Nreloc uint32 + Flags uint32 +} + +// A Reloc represents a Mach-O relocation. +type Reloc struct { + Addr uint32 + Value uint32 + // when Scattered == false && Extern == true, Value is the symbol number. + // when Scattered == false && Extern == false, Value is the section number. + // when Scattered == true, Value is the value that this reloc refers to. + Type uint8 + Len uint8 // 0=byte, 1=word, 2=long, 3=quad + Pcrel bool + Extern bool // valid if Scattered == false + Scattered bool +} + +type Section struct { + SectionHeader + Relocs []Reloc + + // 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 +} + +// Data reads and returns the contents of the Mach-O section. +func (s *Section) Data() ([]byte, error) { + return saferio.ReadDataAt(s.sr, s.Size, 0) +} + +// Open returns a new ReadSeeker reading the Mach-O section. +func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) } + +// A Dylib represents a Mach-O load dynamic library command. +type Dylib struct { + LoadBytes + Name string + Time uint32 + CurrentVersion uint32 + CompatVersion uint32 +} + +// A Symtab represents a Mach-O symbol table command. +type Symtab struct { + LoadBytes + SymtabCmd + Syms []Symbol +} + +// A Dysymtab represents a Mach-O dynamic symbol table command. +type Dysymtab struct { + LoadBytes + DysymtabCmd + IndirectSyms []uint32 // indices into Symtab.Syms +} + +// A Rpath represents a Mach-O rpath command. +type Rpath struct { + LoadBytes + Path string +} + +// A Symbol is a Mach-O 32-bit or 64-bit symbol table entry. +type Symbol struct { + Name string + Type uint8 + Sect uint8 + Desc uint16 + Value uint64 +} + +/* + * Mach-O reader + */ + +// FormatError is returned by some operations if the data does +// not have the correct format for an object file. +type FormatError struct { + off int64 + msg string + val any +} + +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 Mach-O 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 +} + +// NewFile creates a new File for accessing a Mach-O binary in an underlying reader. +// The Mach-O binary is expected to start at position 0 in the ReaderAt. +func NewFile(r io.ReaderAt) (*File, error) { + f := new(File) + sr := io.NewSectionReader(r, 0, 1<<63-1) + + // Read and decode Mach magic to determine byte order, size. + // Magic32 and Magic64 differ only in the bottom bit. + var ident [4]byte + if _, err := r.ReadAt(ident[0:], 0); err != nil { + return nil, err + } + be := binary.BigEndian.Uint32(ident[0:]) + le := binary.LittleEndian.Uint32(ident[0:]) + switch Magic32 &^ 1 { + case be &^ 1: + f.ByteOrder = binary.BigEndian + f.Magic = be + case le &^ 1: + f.ByteOrder = binary.LittleEndian + f.Magic = le + default: + return nil, &FormatError{0, "invalid magic number", nil} + } + + // Read entire file header. + if err := binary.Read(sr, f.ByteOrder, &f.FileHeader); err != nil { + return nil, err + } + + // Then load commands. + offset := int64(fileHeaderSize32) + if f.Magic == Magic64 { + offset = fileHeaderSize64 + } + dat, err := saferio.ReadDataAt(r, uint64(f.Cmdsz), offset) + if err != nil { + return nil, err + } + c := saferio.SliceCap((*Load)(nil), uint64(f.Ncmd)) + if c < 0 { + return nil, &FormatError{offset, "too many load commands", nil} + } + f.Loads = make([]Load, 0, c) + bo := f.ByteOrder + for i := uint32(0); i < f.Ncmd; i++ { + // Each load command begins with uint32 command and length. + if len(dat) < 8 { + return nil, &FormatError{offset, "command block too small", nil} + } + cmd, siz := LoadCmd(bo.Uint32(dat[0:4])), bo.Uint32(dat[4:8]) + if siz < 8 || siz > uint32(len(dat)) { + return nil, &FormatError{offset, "invalid command block size", nil} + } + var cmddat []byte + cmddat, dat = dat[0:siz], dat[siz:] + offset += int64(siz) + var s *Segment + switch cmd { + default: + f.Loads = append(f.Loads, LoadBytes(cmddat)) + + case LoadCmdRpath: + var hdr RpathCmd + b := bytes.NewReader(cmddat) + if err := binary.Read(b, bo, &hdr); err != nil { + return nil, err + } + l := new(Rpath) + if hdr.Path >= uint32(len(cmddat)) { + return nil, &FormatError{offset, "invalid path in rpath command", hdr.Path} + } + l.Path = cstring(cmddat[hdr.Path:]) + l.LoadBytes = LoadBytes(cmddat) + f.Loads = append(f.Loads, l) + + case LoadCmdDylib: + var hdr DylibCmd + b := bytes.NewReader(cmddat) + if err := binary.Read(b, bo, &hdr); err != nil { + return nil, err + } + l := new(Dylib) + if hdr.Name >= uint32(len(cmddat)) { + return nil, &FormatError{offset, "invalid name in dynamic library command", hdr.Name} + } + l.Name = cstring(cmddat[hdr.Name:]) + l.Time = hdr.Time + l.CurrentVersion = hdr.CurrentVersion + l.CompatVersion = hdr.CompatVersion + l.LoadBytes = LoadBytes(cmddat) + f.Loads = append(f.Loads, l) + + case LoadCmdSymtab: + var hdr SymtabCmd + b := bytes.NewReader(cmddat) + if err := binary.Read(b, bo, &hdr); err != nil { + return nil, err + } + strtab := make([]byte, hdr.Strsize) + if _, err := r.ReadAt(strtab, int64(hdr.Stroff)); err != nil { + return nil, err + } + var symsz int + if f.Magic == Magic64 { + symsz = 16 + } else { + symsz = 12 + } + symdat, err := saferio.ReadDataAt(r, uint64(hdr.Nsyms)*uint64(symsz), int64(hdr.Symoff)) + if err != nil { + return nil, err + } + st, err := f.parseSymtab(symdat, strtab, cmddat, &hdr, offset) + if err != nil { + return nil, err + } + f.Loads = append(f.Loads, st) + f.Symtab = st + + case LoadCmdDysymtab: + var hdr DysymtabCmd + b := bytes.NewReader(cmddat) + if err := binary.Read(b, bo, &hdr); err != nil { + return nil, err + } + if hdr.Iundefsym > uint32(len(f.Symtab.Syms)) { + return nil, &FormatError{offset, fmt.Sprintf( + "undefined symbols index in dynamic symbol table command is greater than symbol table length (%d > %d)", + hdr.Iundefsym, len(f.Symtab.Syms)), nil} + } else if hdr.Iundefsym+hdr.Nundefsym > uint32(len(f.Symtab.Syms)) { + return nil, &FormatError{offset, fmt.Sprintf( + "number of undefined symbols after index in dynamic symbol table command is greater than symbol table length (%d > %d)", + hdr.Iundefsym+hdr.Nundefsym, len(f.Symtab.Syms)), nil} + } + dat := make([]byte, hdr.Nindirectsyms*4) + if _, err := r.ReadAt(dat, int64(hdr.Indirectsymoff)); err != nil { + return nil, err + } + x := make([]uint32, hdr.Nindirectsyms) + if err := binary.Read(bytes.NewReader(dat), bo, x); err != nil { + return nil, err + } + st := new(Dysymtab) + st.LoadBytes = LoadBytes(cmddat) + st.DysymtabCmd = hdr + st.IndirectSyms = x + f.Loads = append(f.Loads, st) + f.Dysymtab = st + + case LoadCmdSegment: + var seg32 Segment32 + b := bytes.NewReader(cmddat) + if err := binary.Read(b, bo, &seg32); err != nil { + return nil, err + } + s = new(Segment) + s.LoadBytes = cmddat + s.Cmd = cmd + s.Len = siz + s.Name = cstring(seg32.Name[0:]) + s.Addr = uint64(seg32.Addr) + s.Memsz = uint64(seg32.Memsz) + s.Offset = uint64(seg32.Offset) + s.Filesz = uint64(seg32.Filesz) + s.Maxprot = seg32.Maxprot + s.Prot = seg32.Prot + s.Nsect = seg32.Nsect + s.Flag = seg32.Flag + f.Loads = append(f.Loads, s) + for i := 0; i < int(s.Nsect); i++ { + var sh32 Section32 + if err := binary.Read(b, bo, &sh32); err != nil { + return nil, err + } + sh := new(Section) + sh.Name = cstring(sh32.Name[0:]) + sh.Seg = cstring(sh32.Seg[0:]) + sh.Addr = uint64(sh32.Addr) + sh.Size = uint64(sh32.Size) + sh.Offset = sh32.Offset + sh.Align = sh32.Align + sh.Reloff = sh32.Reloff + sh.Nreloc = sh32.Nreloc + sh.Flags = sh32.Flags + if err := f.pushSection(sh, r); err != nil { + return nil, err + } + } + + case LoadCmdSegment64: + var seg64 Segment64 + b := bytes.NewReader(cmddat) + if err := binary.Read(b, bo, &seg64); err != nil { + return nil, err + } + s = new(Segment) + s.LoadBytes = cmddat + s.Cmd = cmd + s.Len = siz + s.Name = cstring(seg64.Name[0:]) + s.Addr = seg64.Addr + s.Memsz = seg64.Memsz + s.Offset = seg64.Offset + s.Filesz = seg64.Filesz + s.Maxprot = seg64.Maxprot + s.Prot = seg64.Prot + s.Nsect = seg64.Nsect + s.Flag = seg64.Flag + f.Loads = append(f.Loads, s) + for i := 0; i < int(s.Nsect); i++ { + var sh64 Section64 + if err := binary.Read(b, bo, &sh64); err != nil { + return nil, err + } + sh := new(Section) + sh.Name = cstring(sh64.Name[0:]) + sh.Seg = cstring(sh64.Seg[0:]) + sh.Addr = sh64.Addr + sh.Size = sh64.Size + sh.Offset = sh64.Offset + sh.Align = sh64.Align + sh.Reloff = sh64.Reloff + sh.Nreloc = sh64.Nreloc + sh.Flags = sh64.Flags + if err := f.pushSection(sh, r); err != nil { + return nil, err + } + } + } + if s != nil { + if int64(s.Offset) < 0 { + return nil, &FormatError{offset, "invalid section offset", s.Offset} + } + if int64(s.Filesz) < 0 { + return nil, &FormatError{offset, "invalid section file size", s.Filesz} + } + s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Filesz)) + s.ReaderAt = s.sr + } + } + return f, nil +} + +func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset int64) (*Symtab, error) { + bo := f.ByteOrder + c := saferio.SliceCap((*Symbol)(nil), uint64(hdr.Nsyms)) + if c < 0 { + return nil, &FormatError{offset, "too many symbols", nil} + } + symtab := make([]Symbol, 0, c) + b := bytes.NewReader(symdat) + for i := 0; i < int(hdr.Nsyms); i++ { + var n Nlist64 + if f.Magic == Magic64 { + if err := binary.Read(b, bo, &n); err != nil { + return nil, err + } + } else { + var n32 Nlist32 + if err := binary.Read(b, bo, &n32); err != nil { + return nil, err + } + n.Name = n32.Name + n.Type = n32.Type + n.Sect = n32.Sect + n.Desc = n32.Desc + n.Value = uint64(n32.Value) + } + if n.Name >= uint32(len(strtab)) { + return nil, &FormatError{offset, "invalid name in symbol table", n.Name} + } + // We add "_" to Go symbols. Strip it here. See issue 33808. + name := cstring(strtab[n.Name:]) + if strings.Contains(name, ".") && name[0] == '_' { + name = name[1:] + } + symtab = append(symtab, Symbol{ + Name: name, + Type: n.Type, + Sect: n.Sect, + Desc: n.Desc, + Value: n.Value, + }) + } + st := new(Symtab) + st.LoadBytes = LoadBytes(cmddat) + st.Syms = symtab + return st, nil +} + +type relocInfo struct { + Addr uint32 + Symnum uint32 +} + +func (f *File) pushSection(sh *Section, r io.ReaderAt) error { + f.Sections = append(f.Sections, sh) + sh.sr = io.NewSectionReader(r, int64(sh.Offset), int64(sh.Size)) + sh.ReaderAt = sh.sr + + if sh.Nreloc > 0 { + reldat, err := saferio.ReadDataAt(r, uint64(sh.Nreloc)*8, int64(sh.Reloff)) + if err != nil { + return err + } + b := bytes.NewReader(reldat) + + bo := f.ByteOrder + + sh.Relocs = make([]Reloc, sh.Nreloc) + for i := range sh.Relocs { + rel := &sh.Relocs[i] + + var ri relocInfo + if err := binary.Read(b, bo, &ri); err != nil { + return err + } + + if ri.Addr&(1<<31) != 0 { // scattered + rel.Addr = ri.Addr & (1<<24 - 1) + rel.Type = uint8((ri.Addr >> 24) & (1<<4 - 1)) + rel.Len = uint8((ri.Addr >> 28) & (1<<2 - 1)) + rel.Pcrel = ri.Addr&(1<<30) != 0 + rel.Value = ri.Symnum + rel.Scattered = true + } else { + switch bo { + case binary.LittleEndian: + rel.Addr = ri.Addr + rel.Value = ri.Symnum & (1<<24 - 1) + rel.Pcrel = ri.Symnum&(1<<24) != 0 + rel.Len = uint8((ri.Symnum >> 25) & (1<<2 - 1)) + rel.Extern = ri.Symnum&(1<<27) != 0 + rel.Type = uint8((ri.Symnum >> 28) & (1<<4 - 1)) + case binary.BigEndian: + rel.Addr = ri.Addr + rel.Value = ri.Symnum >> 8 + rel.Pcrel = ri.Symnum&(1<<7) != 0 + rel.Len = uint8((ri.Symnum >> 5) & (1<<2 - 1)) + rel.Extern = ri.Symnum&(1<<4) != 0 + rel.Type = uint8(ri.Symnum & (1<<4 - 1)) + default: + panic("unreachable") + } + } + } + } + + return nil +} + +func cstring(b []byte) string { + i := bytes.IndexByte(b, 0) + if i == -1 { + i = len(b) + } + return string(b[0:i]) +} + +// Segment returns the first Segment with the given name, or nil if no such segment exists. +func (f *File) Segment(name string) *Segment { + for _, l := range f.Loads { + if s, ok := l.(*Segment); ok && s.Name == name { + return s + } + } + return nil +} + +// 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 +} + +// DWARF returns the DWARF debug information for the Mach-O file. +func (f *File) DWARF() (*dwarf.Data, error) { + dwarfSuffix := func(s *Section) string { + switch { + case strings.HasPrefix(s.Name, "__debug_"): + return s.Name[8:] + case strings.HasPrefix(s.Name, "__zdebug_"): + return s.Name[9:] + default: + return "" + } + + } + sectionData := func(s *Section) ([]byte, error) { + b, err := s.Data() + if err != nil && uint64(len(b)) < s.Size { + return nil, err + } + + if len(b) >= 12 && string(b[:4]) == "ZLIB" { + dlen := binary.BigEndian.Uint64(b[4:12]) + dbuf := make([]byte, dlen) + r, err := zlib.NewReader(bytes.NewBuffer(b[12:])) + if err != nil { + return nil, err + } + if _, err := io.ReadFull(r, dbuf); err != nil { + return nil, err + } + if err := r.Close(); err != nil { + return nil, err + } + b = dbuf + } + return b, nil + } + + // There are many other DWARF sections, but these + // are the ones the debug/dwarf package uses. + // Don't bother loading others. + var dat = map[string][]byte{"abbrev": nil, "info": nil, "str": nil, "line": nil, "ranges": nil} + for _, s := range f.Sections { + suffix := dwarfSuffix(s) + if suffix == "" { + continue + } + if _, ok := dat[suffix]; !ok { + continue + } + b, err := sectionData(s) + if err != nil { + return nil, err + } + dat[suffix] = b + } + + d, err := dwarf.New(dat["abbrev"], nil, nil, dat["info"], dat["line"], nil, dat["ranges"], dat["str"]) + if err != nil { + return nil, err + } + + // Look for DWARF4 .debug_types sections and DWARF5 sections. + for i, s := range f.Sections { + suffix := dwarfSuffix(s) + if suffix == "" { + continue + } + if _, ok := dat[suffix]; ok { + // Already handled. + continue + } + + b, err := sectionData(s) + if err != nil { + return nil, err + } + + if suffix == "types" { + err = d.AddTypes(fmt.Sprintf("types-%d", i), b) + } else { + err = d.AddSection(".debug_"+suffix, b) + } + if err != nil { + return nil, err + } + } + + return d, nil +} + +// 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. +func (f *File) ImportedSymbols() ([]string, error) { + if f.Dysymtab == nil || f.Symtab == nil { + return nil, &FormatError{0, "missing symbol table", nil} + } + + st := f.Symtab + dt := f.Dysymtab + var all []string + for _, s := range st.Syms[dt.Iundefsym : dt.Iundefsym+dt.Nundefsym] { + all = append(all, s.Name) + } + return all, nil +} + +// ImportedLibraries returns the paths 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) { + var all []string + for _, l := range f.Loads { + if lib, ok := l.(*Dylib); ok { + all = append(all, lib.Name) + } + } + return all, nil +} -- cgit v1.2.3