/
elf.go
2450 lines (2130 loc) · 63.1 KB
/
elf.go
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// 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 ld
import (
"github.com/bir3/gocompiler/src/cmd/internal/notsha256"
"github.com/bir3/gocompiler/src/cmd/internal/objabi"
"github.com/bir3/gocompiler/src/cmd/internal/sys"
"github.com/bir3/gocompiler/src/cmd/link/internal/loader"
"github.com/bir3/gocompiler/src/cmd/link/internal/sym"
"debug/elf"
"encoding/binary"
"encoding/hex"
"fmt"
"github.com/bir3/gocompiler/src/internal/buildcfg"
"os"
"path/filepath"
"runtime"
"sort"
"strings"
)
/*
* Derived from:
* $FreeBSD: src/sys/sys/elf32.h,v 1.8.14.1 2005/12/30 22:13:58 marcel Exp $
* $FreeBSD: src/sys/sys/elf64.h,v 1.10.14.1 2005/12/30 22:13:58 marcel Exp $
* $FreeBSD: src/sys/sys/elf_common.h,v 1.15.8.1 2005/12/30 22:13:58 marcel Exp $
* $FreeBSD: src/sys/alpha/include/elf.h,v 1.14 2003/09/25 01:10:22 peter Exp $
* $FreeBSD: src/sys/amd64/include/elf.h,v 1.18 2004/08/03 08:21:48 dfr Exp $
* $FreeBSD: src/sys/arm/include/elf.h,v 1.5.2.1 2006/06/30 21:42:52 cognet Exp $
* $FreeBSD: src/sys/i386/include/elf.h,v 1.16 2004/08/02 19:12:17 dfr Exp $
* $FreeBSD: src/sys/powerpc/include/elf.h,v 1.7 2004/11/02 09:47:01 ssouhlal Exp $
* $FreeBSD: src/sys/sparc64/include/elf.h,v 1.12 2003/09/25 01:10:26 peter Exp $
*
* Copyright (c) 1996-1998 John D. Polstra. All rights reserved.
* Copyright (c) 2001 David E. O'Brien
* Portions Copyright 2009 The Go Authors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/*
* ELF definitions that are independent of architecture or word size.
*/
/*
* Note header. The ".note" section contains an array of notes. Each
* begins with this header, aligned to a word boundary. Immediately
* following the note header is n_namesz bytes of name, padded to the
* next word boundary. Then comes n_descsz bytes of descriptor, again
* padded to a word boundary. The values of n_namesz and n_descsz do
* not include the padding.
*/
type elfNote struct {
nNamesz uint32
nDescsz uint32
nType uint32
}
/* For accessing the fields of r_info. */
/* For constructing r_info from field values. */
/*
* Relocation types.
*/
const (
ARM_MAGIC_TRAMP_NUMBER = 0x5c000003
)
/*
* Symbol table entries.
*/
/* For accessing the fields of st_info. */
/* For constructing st_info from field values. */
/* For accessing the fields of st_other. */
/*
* ELF header.
*/
type ElfEhdr elf.Header64
/*
* Section header.
*/
type ElfShdr struct {
elf.Section64
shnum elf.SectionIndex
}
/*
* Program header.
*/
type ElfPhdr elf.ProgHeader
/* For accessing the fields of r_info. */
/* For constructing r_info from field values. */
/*
* Symbol table entries.
*/
/* For accessing the fields of st_info. */
/* For constructing st_info from field values. */
/* For accessing the fields of st_other. */
/*
* Go linker interface
*/
const (
ELF64HDRSIZE = 64
ELF64PHDRSIZE = 56
ELF64SHDRSIZE = 64
ELF64RELSIZE = 16
ELF64RELASIZE = 24
ELF64SYMSIZE = 24
ELF32HDRSIZE = 52
ELF32PHDRSIZE = 32
ELF32SHDRSIZE = 40
ELF32SYMSIZE = 16
ELF32RELSIZE = 8
)
/*
* The interface uses the 64-bit structures always,
* to avoid code duplication. The writers know how to
* marshal a 32-bit representation from the 64-bit structure.
*/
var elfstrdat, elfshstrdat []byte
/*
* Total amount of space to reserve at the start of the file
* for Header, PHeaders, SHeaders, and interp.
* May waste some.
* On FreeBSD, cannot be larger than a page.
*/
const (
ELFRESERVE = 4096
)
/*
* We use the 64-bit data structures on both 32- and 64-bit machines
* in order to write the code just once. The 64-bit data structure is
* written in the 32-bit format on the 32-bit machines.
*/
const (
NSECT = 400
)
var (
Nelfsym = 1
elf64 bool
// Either ".rel" or ".rela" depending on which type of relocation the
// target platform uses.
elfRelType string
ehdr ElfEhdr
phdr [NSECT]*ElfPhdr
shdr [NSECT]*ElfShdr
interp string
)
// ELFArch includes target-specific hooks for ELF targets.
// This is initialized by the target-specific Init function
// called by the linker's main function in cmd/link/main.go.
type ELFArch struct {
// TODO: Document these fields.
Androiddynld string
Linuxdynld string
LinuxdynldMusl string
Freebsddynld string
Netbsddynld string
Openbsddynld string
Dragonflydynld string
Solarisdynld string
Reloc1 func(*Link, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int, int64) bool
RelocSize uint32 // size of an ELF relocation record, must match Reloc1.
SetupPLT func(ctxt *Link, ldr *loader.Loader, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym)
// DynamicReadOnly can be set to true to make the .dynamic
// section read-only. By default it is writable.
// This is used by MIPS targets.
DynamicReadOnly bool
}
type Elfstring struct {
s string
off int
}
var elfstr [100]Elfstring
var nelfstr int
var buildinfo []byte
/*
Initialize the global variable that describes the ELF header. It will be updated as
we write section and prog headers.
*/
func Elfinit(ctxt *Link) {
ctxt.IsELF = true
if ctxt.Arch.InFamily(sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X) {
elfRelType = ".rela"
} else {
elfRelType = ".rel"
}
switch ctxt.Arch.Family {
// 64-bit architectures
case sys.PPC64, sys.S390X:
if ctxt.Arch.ByteOrder == binary.BigEndian && ctxt.HeadType != objabi.Hopenbsd {
ehdr.Flags = 1 /* Version 1 ABI */
} else {
ehdr.Flags = 2 /* Version 2 ABI */
}
fallthrough
case sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS64, sys.RISCV64:
if ctxt.Arch.Family == sys.MIPS64 {
ehdr.Flags = 0x20000004 /* MIPS 3 CPIC */
}
if ctxt.Arch.Family == sys.Loong64 {
ehdr.Flags = 0x43 /* DOUBLE_FLOAT, OBJABI_V1 */
}
if ctxt.Arch.Family == sys.RISCV64 {
ehdr.Flags = 0x4 /* RISCV Float ABI Double */
}
elf64 = true
ehdr.Phoff = ELF64HDRSIZE /* Must be ELF64HDRSIZE: first PHdr must follow ELF header */
ehdr.Shoff = ELF64HDRSIZE /* Will move as we add PHeaders */
ehdr.Ehsize = ELF64HDRSIZE /* Must be ELF64HDRSIZE */
ehdr.Phentsize = ELF64PHDRSIZE /* Must be ELF64PHDRSIZE */
ehdr.Shentsize = ELF64SHDRSIZE /* Must be ELF64SHDRSIZE */
// 32-bit architectures
case sys.ARM, sys.MIPS:
if ctxt.Arch.Family == sys.ARM {
// we use EABI on linux/arm, freebsd/arm, netbsd/arm.
if ctxt.HeadType == objabi.Hlinux || ctxt.HeadType == objabi.Hfreebsd || ctxt.HeadType == objabi.Hnetbsd {
// We set a value here that makes no indication of which
// float ABI the object uses, because this is information
// used by the dynamic linker to compare executables and
// shared libraries -- so it only matters for cgo calls, and
// the information properly comes from the object files
// produced by the host C compiler. parseArmAttributes in
// ldelf.go reads that information and updates this field as
// appropriate.
ehdr.Flags = 0x5000002 // has entry point, Version5 EABI
}
} else if ctxt.Arch.Family == sys.MIPS {
ehdr.Flags = 0x50001004 /* MIPS 32 CPIC O32*/
}
fallthrough
default:
ehdr.Phoff = ELF32HDRSIZE
/* Must be ELF32HDRSIZE: first PHdr must follow ELF header */
ehdr.Shoff = ELF32HDRSIZE /* Will move as we add PHeaders */
ehdr.Ehsize = ELF32HDRSIZE /* Must be ELF32HDRSIZE */
ehdr.Phentsize = ELF32PHDRSIZE /* Must be ELF32PHDRSIZE */
ehdr.Shentsize = ELF32SHDRSIZE /* Must be ELF32SHDRSIZE */
}
}
// Make sure PT_LOAD is aligned properly and
// that there is no gap,
// correct ELF loaders will do this implicitly,
// but buggy ELF loaders like the one in some
// versions of QEMU and UPX won't.
func fixElfPhdr(e *ElfPhdr) {
frag := int(e.Vaddr & (e.Align - 1))
e.Off -= uint64(frag)
e.Vaddr -= uint64(frag)
e.Paddr -= uint64(frag)
e.Filesz += uint64(frag)
e.Memsz += uint64(frag)
}
func elf64phdr(out *OutBuf, e *ElfPhdr) {
if e.Type == elf.PT_LOAD {
fixElfPhdr(e)
}
out.Write32(uint32(e.Type))
out.Write32(uint32(e.Flags))
out.Write64(e.Off)
out.Write64(e.Vaddr)
out.Write64(e.Paddr)
out.Write64(e.Filesz)
out.Write64(e.Memsz)
out.Write64(e.Align)
}
func elf32phdr(out *OutBuf, e *ElfPhdr) {
if e.Type == elf.PT_LOAD {
fixElfPhdr(e)
}
out.Write32(uint32(e.Type))
out.Write32(uint32(e.Off))
out.Write32(uint32(e.Vaddr))
out.Write32(uint32(e.Paddr))
out.Write32(uint32(e.Filesz))
out.Write32(uint32(e.Memsz))
out.Write32(uint32(e.Flags))
out.Write32(uint32(e.Align))
}
func elf64shdr(out *OutBuf, e *ElfShdr) {
out.Write32(e.Name)
out.Write32(uint32(e.Type))
out.Write64(uint64(e.Flags))
out.Write64(e.Addr)
out.Write64(e.Off)
out.Write64(e.Size)
out.Write32(e.Link)
out.Write32(e.Info)
out.Write64(e.Addralign)
out.Write64(e.Entsize)
}
func elf32shdr(out *OutBuf, e *ElfShdr) {
out.Write32(e.Name)
out.Write32(uint32(e.Type))
out.Write32(uint32(e.Flags))
out.Write32(uint32(e.Addr))
out.Write32(uint32(e.Off))
out.Write32(uint32(e.Size))
out.Write32(e.Link)
out.Write32(e.Info)
out.Write32(uint32(e.Addralign))
out.Write32(uint32(e.Entsize))
}
func elfwriteshdrs(out *OutBuf) uint32 {
if elf64 {
for i := 0; i < int(ehdr.Shnum); i++ {
elf64shdr(out, shdr[i])
}
return uint32(ehdr.Shnum) * ELF64SHDRSIZE
}
for i := 0; i < int(ehdr.Shnum); i++ {
elf32shdr(out, shdr[i])
}
return uint32(ehdr.Shnum) * ELF32SHDRSIZE
}
func elfsetstring(ctxt *Link, s loader.Sym, str string, off int) {
if nelfstr >= len(elfstr) {
ctxt.Errorf(s, "too many elf strings")
errorexit()
}
elfstr[nelfstr].s = str
elfstr[nelfstr].off = off
nelfstr++
}
func elfwritephdrs(out *OutBuf) uint32 {
if elf64 {
for i := 0; i < int(ehdr.Phnum); i++ {
elf64phdr(out, phdr[i])
}
return uint32(ehdr.Phnum) * ELF64PHDRSIZE
}
for i := 0; i < int(ehdr.Phnum); i++ {
elf32phdr(out, phdr[i])
}
return uint32(ehdr.Phnum) * ELF32PHDRSIZE
}
func newElfPhdr() *ElfPhdr {
e := new(ElfPhdr)
if ehdr.Phnum >= NSECT {
Errorf(nil, "too many phdrs")
} else {
phdr[ehdr.Phnum] = e
ehdr.Phnum++
}
if elf64 {
ehdr.Shoff += ELF64PHDRSIZE
} else {
ehdr.Shoff += ELF32PHDRSIZE
}
return e
}
func newElfShdr(name int64) *ElfShdr {
e := new(ElfShdr)
e.Name = uint32(name)
e.shnum = elf.SectionIndex(ehdr.Shnum)
if ehdr.Shnum >= NSECT {
Errorf(nil, "too many shdrs")
} else {
shdr[ehdr.Shnum] = e
ehdr.Shnum++
}
return e
}
func getElfEhdr() *ElfEhdr {
return &ehdr
}
func elf64writehdr(out *OutBuf) uint32 {
out.Write(ehdr.Ident[:])
out.Write16(uint16(ehdr.Type))
out.Write16(uint16(ehdr.Machine))
out.Write32(uint32(ehdr.Version))
out.Write64(ehdr.Entry)
out.Write64(ehdr.Phoff)
out.Write64(ehdr.Shoff)
out.Write32(ehdr.Flags)
out.Write16(ehdr.Ehsize)
out.Write16(ehdr.Phentsize)
out.Write16(ehdr.Phnum)
out.Write16(ehdr.Shentsize)
out.Write16(ehdr.Shnum)
out.Write16(ehdr.Shstrndx)
return ELF64HDRSIZE
}
func elf32writehdr(out *OutBuf) uint32 {
out.Write(ehdr.Ident[:])
out.Write16(uint16(ehdr.Type))
out.Write16(uint16(ehdr.Machine))
out.Write32(uint32(ehdr.Version))
out.Write32(uint32(ehdr.Entry))
out.Write32(uint32(ehdr.Phoff))
out.Write32(uint32(ehdr.Shoff))
out.Write32(ehdr.Flags)
out.Write16(ehdr.Ehsize)
out.Write16(ehdr.Phentsize)
out.Write16(ehdr.Phnum)
out.Write16(ehdr.Shentsize)
out.Write16(ehdr.Shnum)
out.Write16(ehdr.Shstrndx)
return ELF32HDRSIZE
}
func elfwritehdr(out *OutBuf) uint32 {
if elf64 {
return elf64writehdr(out)
}
return elf32writehdr(out)
}
/* Taken directly from the definition document for ELF64. */
func elfhash(name string) uint32 {
var h uint32
for i := 0; i < len(name); i++ {
h = (h << 4) + uint32(name[i])
if g := h & 0xf0000000; g != 0 {
h ^= g >> 24
}
h &= 0x0fffffff
}
return h
}
func elfWriteDynEntSym(ctxt *Link, s *loader.SymbolBuilder, tag elf.DynTag, t loader.Sym) {
Elfwritedynentsymplus(ctxt, s, tag, t, 0)
}
func Elfwritedynent(arch *sys.Arch, s *loader.SymbolBuilder, tag elf.DynTag, val uint64) {
if elf64 {
s.AddUint64(arch, uint64(tag))
s.AddUint64(arch, val)
} else {
s.AddUint32(arch, uint32(tag))
s.AddUint32(arch, uint32(val))
}
}
func Elfwritedynentsymplus(ctxt *Link, s *loader.SymbolBuilder, tag elf.DynTag, t loader.Sym, add int64) {
if elf64 {
s.AddUint64(ctxt.Arch, uint64(tag))
} else {
s.AddUint32(ctxt.Arch, uint32(tag))
}
s.AddAddrPlus(ctxt.Arch, t, add)
}
func elfwritedynentsymsize(ctxt *Link, s *loader.SymbolBuilder, tag elf.DynTag, t loader.Sym) {
if elf64 {
s.AddUint64(ctxt.Arch, uint64(tag))
} else {
s.AddUint32(ctxt.Arch, uint32(tag))
}
s.AddSize(ctxt.Arch, t)
}
func elfinterp(sh *ElfShdr, startva uint64, resoff uint64, p string) int {
interp = p
n := len(interp) + 1
sh.Addr = startva + resoff - uint64(n)
sh.Off = resoff - uint64(n)
sh.Size = uint64(n)
return n
}
func elfwriteinterp(out *OutBuf) int {
sh := elfshname(".interp")
out.SeekSet(int64(sh.Off))
out.WriteString(interp)
out.Write8(0)
return int(sh.Size)
}
// member of .gnu.attributes of MIPS for fpAbi
const (
// No floating point is present in the module (default)
MIPS_FPABI_NONE = 0
// FP code in the module uses the FP32 ABI for a 32-bit ABI
MIPS_FPABI_ANY = 1
// FP code in the module only uses single precision ABI
MIPS_FPABI_SINGLE = 2
// FP code in the module uses soft-float ABI
MIPS_FPABI_SOFT = 3
// FP code in the module assumes an FPU with FR=1 and has 12
// callee-saved doubles. Historic, no longer supported.
MIPS_FPABI_HIST = 4
// FP code in the module uses the FPXX ABI
MIPS_FPABI_FPXX = 5
// FP code in the module uses the FP64 ABI
MIPS_FPABI_FP64 = 6
// FP code in the module uses the FP64A ABI
MIPS_FPABI_FP64A = 7
)
func elfMipsAbiFlags(sh *ElfShdr, startva uint64, resoff uint64) int {
n := 24
sh.Addr = startva + resoff - uint64(n)
sh.Off = resoff - uint64(n)
sh.Size = uint64(n)
sh.Type = uint32(elf.SHT_MIPS_ABIFLAGS)
sh.Flags = uint64(elf.SHF_ALLOC)
return n
}
// Layout is given by this C definition:
//
// typedef struct
// {
// /* Version of flags structure. */
// uint16_t version;
// /* The level of the ISA: 1-5, 32, 64. */
// uint8_t isa_level;
// /* The revision of ISA: 0 for MIPS V and below, 1-n otherwise. */
// uint8_t isa_rev;
// /* The size of general purpose registers. */
// uint8_t gpr_size;
// /* The size of co-processor 1 registers. */
// uint8_t cpr1_size;
// /* The size of co-processor 2 registers. */
// uint8_t cpr2_size;
// /* The floating-point ABI. */
// uint8_t fp_abi;
// /* Processor-specific extension. */
// uint32_t isa_ext;
// /* Mask of ASEs used. */
// uint32_t ases;
// /* Mask of general flags. */
// uint32_t flags1;
// uint32_t flags2;
// } Elf_Internal_ABIFlags_v0;
func elfWriteMipsAbiFlags(ctxt *Link) int {
sh := elfshname(".MIPS.abiflags")
ctxt.Out.SeekSet(int64(sh.Off))
ctxt.Out.Write16(0) // version
ctxt.Out.Write8(32) // isaLevel
ctxt.Out.Write8(1) // isaRev
ctxt.Out.Write8(1) // gprSize
ctxt.Out.Write8(1) // cpr1Size
ctxt.Out.Write8(0) // cpr2Size
if buildcfg.GOMIPS == "softfloat" {
ctxt.Out.Write8(MIPS_FPABI_SOFT) // fpAbi
} else {
// Go cannot make sure non odd-number-fpr is used (ie, in load a double from memory).
// So, we mark the object is MIPS I style paired float/double register scheme,
// aka MIPS_FPABI_ANY. If we mark the object as FPXX, the kernel may use FR=1 mode,
// then we meet some problem.
// Note: MIPS_FPABI_ANY is bad naming: in fact it is MIPS I style FPR usage.
// It is not for 'ANY'.
// TODO: switch to FPXX after be sure that no odd-number-fpr is used.
ctxt.Out.Write8(MIPS_FPABI_ANY) // fpAbi
}
ctxt.Out.Write32(0) // isaExt
ctxt.Out.Write32(0) // ases
ctxt.Out.Write32(0) // flags1
ctxt.Out.Write32(0) // flags2
return int(sh.Size)
}
func elfnote(sh *ElfShdr, startva uint64, resoff uint64, sizes ...int) int {
n := resoff % 4
// if section contains multiple notes (as is the case with FreeBSD signature),
// multiple note sizes can be specified
for _, sz := range sizes {
n += 3*4 + uint64(sz)
}
sh.Type = uint32(elf.SHT_NOTE)
sh.Flags = uint64(elf.SHF_ALLOC)
sh.Addralign = 4
sh.Addr = startva + resoff - n
sh.Off = resoff - n
sh.Size = n - resoff%4
return int(n)
}
func elfwritenotehdr(out *OutBuf, str string, namesz uint32, descsz uint32, tag uint32) *ElfShdr {
sh := elfshname(str)
// Write Elf_Note header.
out.SeekSet(int64(sh.Off))
out.Write32(namesz)
out.Write32(descsz)
out.Write32(tag)
return sh
}
// NetBSD Signature (as per sys/exec_elf.h)
const (
ELF_NOTE_NETBSD_NAMESZ = 7
ELF_NOTE_NETBSD_DESCSZ = 4
ELF_NOTE_NETBSD_TAG = 1
ELF_NOTE_NETBSD_VERSION = 700000000 /* NetBSD 7.0 */
)
var ELF_NOTE_NETBSD_NAME = []byte("NetBSD\x00")
func elfnetbsdsig(sh *ElfShdr, startva uint64, resoff uint64) int {
n := int(Rnd(ELF_NOTE_NETBSD_NAMESZ, 4) + Rnd(ELF_NOTE_NETBSD_DESCSZ, 4))
return elfnote(sh, startva, resoff, n)
}
func elfwritenetbsdsig(out *OutBuf) int {
// Write Elf_Note header.
sh := elfwritenotehdr(out, ".note.netbsd.ident", ELF_NOTE_NETBSD_NAMESZ, ELF_NOTE_NETBSD_DESCSZ, ELF_NOTE_NETBSD_TAG)
if sh == nil {
return 0
}
// Followed by NetBSD string and version.
out.Write(ELF_NOTE_NETBSD_NAME)
out.Write8(0)
out.Write32(ELF_NOTE_NETBSD_VERSION)
return int(sh.Size)
}
// The race detector can't handle ASLR (address space layout randomization).
// ASLR is on by default for NetBSD, so we turn the ASLR off explicitly
// using a magic elf Note when building race binaries.
func elfnetbsdpax(sh *ElfShdr, startva uint64, resoff uint64) int {
n := int(Rnd(4, 4) + Rnd(4, 4))
return elfnote(sh, startva, resoff, n)
}
func elfwritenetbsdpax(out *OutBuf) int {
sh := elfwritenotehdr(out, ".note.netbsd.pax", 4 /* length of PaX\x00 */, 4 /* length of flags */, 0x03 /* PaX type */)
if sh == nil {
return 0
}
out.Write([]byte("PaX\x00"))
out.Write32(0x20) // 0x20 = Force disable ASLR
return int(sh.Size)
}
// OpenBSD Signature
const (
ELF_NOTE_OPENBSD_NAMESZ = 8
ELF_NOTE_OPENBSD_DESCSZ = 4
ELF_NOTE_OPENBSD_TAG = 1
ELF_NOTE_OPENBSD_VERSION = 0
)
var ELF_NOTE_OPENBSD_NAME = []byte("OpenBSD\x00")
func elfopenbsdsig(sh *ElfShdr, startva uint64, resoff uint64) int {
n := ELF_NOTE_OPENBSD_NAMESZ + ELF_NOTE_OPENBSD_DESCSZ
return elfnote(sh, startva, resoff, n)
}
func elfwriteopenbsdsig(out *OutBuf) int {
// Write Elf_Note header.
sh := elfwritenotehdr(out, ".note.openbsd.ident", ELF_NOTE_OPENBSD_NAMESZ, ELF_NOTE_OPENBSD_DESCSZ, ELF_NOTE_OPENBSD_TAG)
if sh == nil {
return 0
}
// Followed by OpenBSD string and version.
out.Write(ELF_NOTE_OPENBSD_NAME)
out.Write32(ELF_NOTE_OPENBSD_VERSION)
return int(sh.Size)
}
// FreeBSD Signature (as per sys/elf_common.h)
const (
ELF_NOTE_FREEBSD_NAMESZ = 8
ELF_NOTE_FREEBSD_DESCSZ = 4
ELF_NOTE_FREEBSD_ABI_TAG = 1
ELF_NOTE_FREEBSD_NOINIT_TAG = 2
ELF_NOTE_FREEBSD_FEATURE_CTL_TAG = 4
ELF_NOTE_FREEBSD_VERSION = 1203000 // 12.3-RELEASE
ELF_NOTE_FREEBSD_FCTL_ASLR_DISABLE = 0x1
)
const ELF_NOTE_FREEBSD_NAME = "FreeBSD\x00"
func elffreebsdsig(sh *ElfShdr, startva uint64, resoff uint64) int {
n := ELF_NOTE_FREEBSD_NAMESZ + ELF_NOTE_FREEBSD_DESCSZ
// FreeBSD signature section contains 3 equally sized notes
return elfnote(sh, startva, resoff, n, n, n)
}
// elfwritefreebsdsig writes FreeBSD .note section.
//
// See https://www.netbsd.org/docs/kernel/elf-notes.html for the description of
// a Note element format and
// https://github.com/freebsd/freebsd-src/blob/main/sys/sys/elf_common.h#L790
// for the FreeBSD-specific values.
func elfwritefreebsdsig(out *OutBuf) int {
sh := elfshname(".note.tag")
if sh == nil {
return 0
}
out.SeekSet(int64(sh.Off))
// NT_FREEBSD_ABI_TAG
out.Write32(ELF_NOTE_FREEBSD_NAMESZ)
out.Write32(ELF_NOTE_FREEBSD_DESCSZ)
out.Write32(ELF_NOTE_FREEBSD_ABI_TAG)
out.WriteString(ELF_NOTE_FREEBSD_NAME)
out.Write32(ELF_NOTE_FREEBSD_VERSION)
// NT_FREEBSD_NOINIT_TAG
out.Write32(ELF_NOTE_FREEBSD_NAMESZ)
out.Write32(ELF_NOTE_FREEBSD_DESCSZ)
out.Write32(ELF_NOTE_FREEBSD_NOINIT_TAG)
out.WriteString(ELF_NOTE_FREEBSD_NAME)
out.Write32(0)
// NT_FREEBSD_FEATURE_CTL
out.Write32(ELF_NOTE_FREEBSD_NAMESZ)
out.Write32(ELF_NOTE_FREEBSD_DESCSZ)
out.Write32(ELF_NOTE_FREEBSD_FEATURE_CTL_TAG)
out.WriteString(ELF_NOTE_FREEBSD_NAME)
if *flagRace {
// The race detector can't handle ASLR, turn the ASLR off when compiling with -race.
out.Write32(ELF_NOTE_FREEBSD_FCTL_ASLR_DISABLE)
} else {
out.Write32(0)
}
return int(sh.Size)
}
func addbuildinfo(val string) {
if val == "gobuildid" {
buildID := *flagBuildid
if buildID == "" {
Exitf("-B gobuildid requires a Go build ID supplied via -buildid")
}
hashedBuildID := notsha256.Sum256([]byte(buildID))
buildinfo = hashedBuildID[:20]
return
}
if !strings.HasPrefix(val, "0x") {
Exitf("-B argument must start with 0x: %s", val)
}
ov := val
val = val[2:]
const maxLen = 32
if hex.DecodedLen(len(val)) > maxLen {
Exitf("-B option too long (max %d digits): %s", maxLen, ov)
}
b, err := hex.DecodeString(val)
if err != nil {
if err == hex.ErrLength {
Exitf("-B argument must have even number of digits: %s", ov)
}
if inv, ok := err.(hex.InvalidByteError); ok {
Exitf("-B argument contains invalid hex digit %c: %s", byte(inv), ov)
}
Exitf("-B argument contains invalid hex: %s", ov)
}
buildinfo = b
}
// Build info note
const (
ELF_NOTE_BUILDINFO_NAMESZ = 4
ELF_NOTE_BUILDINFO_TAG = 3
)
var ELF_NOTE_BUILDINFO_NAME = []byte("GNU\x00")
func elfbuildinfo(sh *ElfShdr, startva uint64, resoff uint64) int {
n := int(ELF_NOTE_BUILDINFO_NAMESZ + Rnd(int64(len(buildinfo)), 4))
return elfnote(sh, startva, resoff, n)
}
func elfgobuildid(sh *ElfShdr, startva uint64, resoff uint64) int {
n := len(ELF_NOTE_GO_NAME) + int(Rnd(int64(len(*flagBuildid)), 4))
return elfnote(sh, startva, resoff, n)
}
func elfwritebuildinfo(out *OutBuf) int {
sh := elfwritenotehdr(out, ".note.gnu.build-id", ELF_NOTE_BUILDINFO_NAMESZ, uint32(len(buildinfo)), ELF_NOTE_BUILDINFO_TAG)
if sh == nil {
return 0
}
out.Write(ELF_NOTE_BUILDINFO_NAME)
out.Write(buildinfo)
var zero = make([]byte, 4)
out.Write(zero[:int(Rnd(int64(len(buildinfo)), 4)-int64(len(buildinfo)))])
return int(sh.Size)
}
func elfwritegobuildid(out *OutBuf) int {
sh := elfwritenotehdr(out, ".note.go.buildid", uint32(len(ELF_NOTE_GO_NAME)), uint32(len(*flagBuildid)), ELF_NOTE_GOBUILDID_TAG)
if sh == nil {
return 0
}
out.Write(ELF_NOTE_GO_NAME)
out.Write([]byte(*flagBuildid))
var zero = make([]byte, 4)
out.Write(zero[:int(Rnd(int64(len(*flagBuildid)), 4)-int64(len(*flagBuildid)))])
return int(sh.Size)
}
// Go specific notes
const (
ELF_NOTE_GOPKGLIST_TAG = 1
ELF_NOTE_GOABIHASH_TAG = 2
ELF_NOTE_GODEPS_TAG = 3
ELF_NOTE_GOBUILDID_TAG = 4
)
var ELF_NOTE_GO_NAME = []byte("Go\x00\x00")
var elfverneed int
type Elfaux struct {
next *Elfaux
num int
vers string
}
type Elflib struct {
next *Elflib
aux *Elfaux
file string
}
func addelflib(list **Elflib, file string, vers string) *Elfaux {
var lib *Elflib
for lib = *list; lib != nil; lib = lib.next {
if lib.file == file {
goto havelib
}
}
lib = new(Elflib)
lib.next = *list
lib.file = file
*list = lib
havelib:
for aux := lib.aux; aux != nil; aux = aux.next {
if aux.vers == vers {
return aux
}
}
aux := new(Elfaux)
aux.next = lib.aux
aux.vers = vers
lib.aux = aux
return aux
}
func elfdynhash(ctxt *Link) {
if !ctxt.IsELF {
return
}
nsym := Nelfsym
ldr := ctxt.loader
s := ldr.CreateSymForUpdate(".hash", 0)
s.SetType(sym.SELFROSECT)
i := nsym
nbucket := 1
for i > 0 {
nbucket++
i >>= 1
}
var needlib *Elflib
need := make([]*Elfaux, nsym)
chain := make([]uint32, nsym)
buckets := make([]uint32, nbucket)
for _, sy := range ldr.DynidSyms() {
dynid := ldr.SymDynid(sy)
if ldr.SymDynimpvers(sy) != "" {
need[dynid] = addelflib(&needlib, ldr.SymDynimplib(sy), ldr.SymDynimpvers(sy))
}
name := ldr.SymExtname(sy)
hc := elfhash(name)
b := hc % uint32(nbucket)
chain[dynid] = buckets[b]
buckets[b] = uint32(dynid)
}
// s390x (ELF64) hash table entries are 8 bytes
if ctxt.Arch.Family == sys.S390X {
s.AddUint64(ctxt.Arch, uint64(nbucket))
s.AddUint64(ctxt.Arch, uint64(nsym))
for i := 0; i < nbucket; i++ {
s.AddUint64(ctxt.Arch, uint64(buckets[i]))
}
for i := 0; i < nsym; i++ {
s.AddUint64(ctxt.Arch, uint64(chain[i]))
}
} else {
s.AddUint32(ctxt.Arch, uint32(nbucket))
s.AddUint32(ctxt.Arch, uint32(nsym))
for i := 0; i < nbucket; i++ {
s.AddUint32(ctxt.Arch, buckets[i])
}
for i := 0; i < nsym; i++ {
s.AddUint32(ctxt.Arch, chain[i])
}
}