mirror of
https://github.com/wader/fq.git
synced 2024-11-23 18:56:52 +03:00
507 lines
14 KiB
Go
507 lines
14 KiB
Go
package elf
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// https://en.wikipedia.org/wiki/Executable_and_Linkable_Format
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// https://man7.org/linux/man-pages/man5/elf.5.html
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// https://github.com/torvalds/linux/blob/master/include/uapi/linux/elf.h
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import (
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"strings"
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"github.com/wader/fq/format"
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"github.com/wader/fq/format/registry"
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"github.com/wader/fq/pkg/decode"
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)
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// TODO: p_type hi/lo
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func init() {
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registry.MustRegister(decode.Format{
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Name: format.ELF,
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Description: "Executable and Linkable Format",
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Groups: []string{format.PROBE},
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DecodeFn: elfDecode,
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})
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}
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//nolint:revive
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const (
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LITTLE_ENDIAN = 1
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BIG_ENDIAN = 2
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)
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var endianNames = decode.UToStr{
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LITTLE_ENDIAN: "little-endian",
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BIG_ENDIAN: "big-endian",
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}
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var classBits = decode.UToU{
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1: 32,
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2: 64,
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}
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var osABINames = decode.UToStr{
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0: "Sysv",
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1: "HPUX",
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2: "NetBSD",
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3: "Linux",
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4: "Hurd",
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5: "86open",
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6: "Solaris",
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7: "Monterey",
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8: "Irix",
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9: "FreeBSD",
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10: "Tru64",
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11: "Modesto",
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12: "OpenBSD",
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97: "Arm",
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255: "Standalone",
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}
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//nolint:revive
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const (
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SHT_NULL = 0x0
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SHT_PROGBITS = 0x1
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SHT_SYMTAB = 0x2
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SHT_STRTAB = 0x3
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SHT_RELA = 0x4
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SHT_HASH = 0x5
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SHT_DYNAMIC = 0x6
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SHT_NOTE = 0x7
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SHT_NOBITS = 0x8
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SHT_REL = 0x9
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SHT_SHLIB = 0x0a
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SHT_DYNSYM = 0x0b
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SHT_INIT_ARRAY = 0x0e
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SHT_FINI_ARRAY = 0x0f
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SHT_PREINIT_ARRAY = 0x10
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SHT_GROUP = 0x11
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SHT_SYMTAB_SHNDX = 0x12
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SHT_NUM = 0x13
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SHT_LOOS = 0x60000000
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)
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var shTypeNames = decode.UToStr{
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SHT_NULL: "SHT_NULL",
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SHT_PROGBITS: "SHT_PROGBITS",
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SHT_SYMTAB: "SHT_SYMTAB",
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SHT_STRTAB: "SHT_STRTAB",
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SHT_RELA: "SHT_RELA",
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SHT_HASH: "SHT_HASH",
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SHT_DYNAMIC: "SHT_DYNAMIC",
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SHT_NOTE: "SHT_NOTE",
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SHT_NOBITS: "SHT_NOBITS",
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SHT_REL: "SHT_REL",
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SHT_SHLIB: "SHT_SHLIB",
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SHT_DYNSYM: "SHT_DYNSYM",
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SHT_INIT_ARRAY: "SHT_INIT_ARRAY",
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SHT_FINI_ARRAY: "SHT_FINI_ARRAY",
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SHT_PREINIT_ARRAY: "SHT_PREINIT_ARRAY",
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SHT_GROUP: "SHT_GROUP",
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SHT_SYMTAB_SHNDX: "SHT_SYMTAB_SHNDX",
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SHT_NUM: "SHT_NUM",
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SHT_LOOS: "SHT_LOOS",
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}
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func strIndexNull(idx int, s string) string {
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if idx > len(s) {
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return ""
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}
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i := strings.IndexByte(s[idx:], 0)
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if i == -1 {
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return s
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}
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return s[idx : idx+i]
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}
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func mapStrTable(table string) func(decode.Scalar) (decode.Scalar, error) {
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return func(s decode.Scalar) (decode.Scalar, error) {
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uv, ok := s.Actual.(uint64)
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if !ok {
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return s, nil
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}
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s.Sym = strIndexNull(int(uv), table)
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return s, nil
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}
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}
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func elfDecode(d *decode.D, in interface{}) interface{} {
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d.AssertAtLeastBitsLeft(128 * 8)
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var archBits int
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var endian uint64
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d.FieldStruct("ident", func(d *decode.D) {
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d.FieldRawLen("magic", 4*8, d.AssertBitBuf([]byte("\x7fELF")))
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archBits = int(d.FieldU8("class", d.MapUToUSym(classBits)))
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endian = d.FieldU8("data", d.MapUToStrSym(endianNames))
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d.FieldU8("version")
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d.FieldU8("os_abi", d.MapUToStrSym(osABINames))
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d.FieldU8("abi_version")
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d.FieldRawLen("pad", 7*8, d.BitBufIsZero)
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})
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switch endian {
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case LITTLE_ENDIAN:
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d.Endian = decode.LittleEndian
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case BIG_ENDIAN:
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d.Endian = decode.BigEndian
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default:
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d.Fatalf("unknown endian")
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}
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// TODO: hex functions?
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d.FieldU16("type", d.MapUToStrSym(decode.UToStr{
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0x00: "None",
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0x01: "Rel",
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0x02: "Exec",
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0x03: "Dyn",
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0x04: "Core",
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0xfe00: "Loos",
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0xfeff: "Hios",
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0xff00: "Loproc",
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0xffff: "Hiproc",
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}), d.Hex)
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d.FieldU16("machine", d.MapUToStrSym(decode.UToStr{
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0x00: "No specific instruction set",
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0x01: "AT&T WE 32100",
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0x02: "SPARC",
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0x03: "x86",
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0x04: "Motorola 68000 (M68k)",
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0x05: "Motorola 88000 (M88k)",
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0x06: "Intel MCU",
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0x07: "Intel 80860",
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0x08: "MIPS",
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0x09: "IBM_System/370",
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0x0a: "MIPS RS3000 Little-endian",
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0x0e: "Hewlett-Packard PA-RISC",
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0x0f: "Reserved for future use",
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0x13: "Intel 80960",
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0x14: "PowerPC",
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0x15: "PowerPC (64-bit)",
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0x16: "S390, including S390x",
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0x17: "IBM SPU/SPC",
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0x24: "NEC V800",
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0x25: "Fujitsu FR20",
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0x26: "TRW RH-32",
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0x27: "Motorola RCE",
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0x28: "ARM (up to ARMv7/Aarch32)",
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0x29: "Digital Alpha",
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0x2a: "SuperH",
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0x2b: "SPARC Version 9",
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0x2c: "Siemens TriCore embedded processor",
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0x2d: "Argonaut RISC Core",
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0x2e: "Hitachi H8/300",
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0x2f: "Hitachi H8/300H",
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0x30: "Hitachi H8S",
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0x31: "Hitachi H8/500",
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0x32: "IA-64",
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0x33: "Stanford MIPS-X",
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0x34: "Motorola ColdFire",
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0x35: "Motorola M68HC12",
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0x36: "Fujitsu MMA Multimedia Accelerator",
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0x37: "Siemens PCP",
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0x38: "Sony nCPU embedded RISC processor",
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0x39: "Denso NDR1 microprocessor",
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0x3a: "Motorola Star*Core processor",
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0x3b: "Toyota ME16 processor",
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0x3c: "STMicroelectronics ST100 processor",
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0x3d: "Advanced Logic Corp. TinyJ embedded processor family",
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0x3e: "AMD x86-64",
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0x8c: "TMS320C6000 Family",
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0xb7: "ARM 64-bits (ARMv8/Aarch64)",
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0xf3: "RISC-V",
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0xf7: "Berkeley Packet Filter",
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0x101: "WDC 65C816",
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}), d.Hex)
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d.FieldU32("version")
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d.FieldU("entry", archBits)
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phoff := d.FieldU("phoff", archBits)
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shoff := d.FieldU("shoff", archBits)
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d.FieldU32("flags")
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d.FieldU16("ehsize")
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phsize := d.FieldU16("phentsize")
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phnum := d.FieldU16("phnum")
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shentsize := d.FieldU16("shentsize")
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shnum := d.FieldU16("shnum")
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shstrndx := d.FieldU16("shstrndx")
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// TODO: make this nicer, API to update fields?
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// TODO: is wrong: string table is one large string to index into
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// TODO: and string can overlap
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var strIndexTable string
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if shstrndx != 0 {
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var strTableOffset uint64
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var strTableSize uint64
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d.RangeFn(int64((shoff+shstrndx*shentsize)*8), int64(shentsize*8), func(d *decode.D) {
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d.SeekRel(32)
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d.SeekRel(32)
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d.SeekRel(int64(archBits))
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d.SeekRel(int64(archBits))
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strTableOffset = d.U(archBits)
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strTableSize = d.U(archBits)
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_ = strIndexTable
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})
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strIndexTable = string(d.BytesRange(int64(strTableOffset*8), int(strTableSize)*8))
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}
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// d.DecodeRangeFn(int64(phoff)*8, int64(phnum*phsize*8), func(d *decode.D) {
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d.FieldArray("program_headers", func(d *decode.D) {
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for i := uint64(0); i < phnum; i++ {
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d.SeekAbs(int64(phoff*8) + int64(i*phsize*8))
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pTypeNames := decode.UToStr{
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0x00000000: "PT_NULL",
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0x00000001: "PT_LOAD",
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0x00000002: "PT_DYNAMIC",
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0x00000003: "PT_INTERP",
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0x00000004: "PT_NOTE",
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0x00000005: "PT_SHLIB",
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0x00000006: "PT_PHDR",
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0x00000007: "PT_TLS",
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0x60000000: "PT_LOOS",
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0x6fffffff: "PT_HIOS",
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0x70000000: "PT_LOPROC",
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0x7fffffff: "PT_HIPROC",
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}
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pFlags := func(d *decode.D) {
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d.FieldStruct("p_flags", func(d *decode.D) {
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if d.Endian == decode.LittleEndian {
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d.FieldU5("unused0")
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d.FieldBool("PF_R")
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d.FieldBool("PF_W")
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d.FieldBool("PF_X")
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d.FieldU24("unused1")
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} else {
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d.FieldU29("unused0")
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d.FieldBool("PF_R")
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d.FieldBool("PF_W")
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d.FieldBool("PF_X")
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}
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})
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}
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d.FieldStruct("program_header", func(d *decode.D) {
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var offset uint64
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var size uint64
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switch archBits {
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case 32:
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d.FieldUFn("p_type", func(d *decode.D) uint64 { return d.U32() & 0xf }, d.MapUToStrSym(pTypeNames))
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offset = d.FieldU("p_offset", archBits)
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d.FieldU("p_vaddr", archBits)
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d.FieldU("p_paddr", archBits)
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size = d.FieldU32("p_filesz")
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d.FieldU32("p_memsz")
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pFlags(d)
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d.FieldU32("p_align")
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case 64:
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d.FieldUFn("p_type", func(d *decode.D) uint64 { return d.U32() & 0xf }, d.MapUToStrSym(pTypeNames))
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pFlags(d)
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offset = d.FieldU("p_offset", archBits)
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d.FieldU("p_vaddr", archBits)
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d.FieldU("p_paddr", archBits)
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size = d.FieldU64("p_filesz")
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d.FieldU64("p_memsz")
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d.FieldU64("p_align")
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}
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d.RangeFn(int64(offset*8), int64(size*8), func(d *decode.D) {
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d.FieldRawLen("data", d.BitsLeft())
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})
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})
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}
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})
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// })
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// d.DecodeRangeFn(int64(shoff)*8, int64(shnum*shentsize*8), func(d *decode.D) {
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d.FieldArray("section_headers", func(d *decode.D) {
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for i := uint64(0); i < shnum; i++ {
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d.SeekAbs(int64(shoff*8) + int64(i*shentsize*8))
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shFlags := func(d *decode.D, archBits int) {
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d.FieldStruct("sh_flags", func(d *decode.D) {
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if d.Endian == decode.LittleEndian {
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d.FieldBool("SHF_LINK_ORDER")
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d.FieldBool("SHF_INFO_LINK")
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d.FieldBool("SHF_STRINGS")
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d.FieldBool("SHF_MERGE")
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d.FieldU1("unused0")
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d.FieldBool("SHF_EXECINSTR")
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d.FieldBool("SHF_ALLOC")
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d.FieldBool("SHF_WRITE")
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d.FieldBool("SHF_TLS")
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d.FieldBool("SHF_GROUP")
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d.FieldBool("SHF_OS_NONCONFORMING")
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d.FieldU9("unused1")
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d.FieldU8("os_specific")
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d.FieldU4("processor_specific")
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if archBits == 64 {
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d.FieldU32("unused2")
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}
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} else {
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// TODO: add.FieldUnused that is per decoder?
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if archBits == 64 {
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d.FieldU32("unused0")
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}
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d.FieldU4("processor_specific")
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d.FieldU8("os_specific")
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d.FieldU9("unused1")
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d.FieldBool("SHF_TLS")
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d.FieldBool("SHF_GROUP")
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d.FieldBool("SHF_OS_NONCONFORMING")
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d.FieldBool("SHF_LINK_ORDER")
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d.FieldBool("SHF_INFO_LINK")
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d.FieldBool("SHF_STRINGS")
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d.FieldBool("SHF_MERGE")
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d.FieldU1("unused2")
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d.FieldBool("SHF_EXECINSTR")
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d.FieldBool("SHF_ALLOC")
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d.FieldBool("SHF_WRITE")
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// 0x1 SHF_WRITE Writable
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// 0x2 SHF_ALLOC Occupies memory during execution
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// 0x4 SHF_EXECINSTR Executable
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// 0x10 SHF_MERGE Might be merged
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// 0x20 SHF_STRINGS Contains null-terminated strings
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// 0x40 SHF_INFO_LINK 'sh_info' contains SHT index
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// 0x80 SHF_LINK_ORDER Preserve order after combining
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// 0x100 SHF_OS_NONCONFORMING Non-standard OS specific handling required
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// 0x200 SHF_GROUP Section is member of a group
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// 0x400 SHF_TLS Section hold thread-local data
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// 0x0ff00000 SHF_MASKOS OS-specific
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// 0xf0000000 SHF_MASKPROC Processor-specific
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// 0x4000000 SHF_ORDERED Special ordering requirement (Solaris)
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// 0x8000000 SHF_EXCLUDE Section is excluded unless referenced or allocated (Solaris)
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}
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})
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}
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d.FieldStruct("section_header", func(d *decode.D) {
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var offset uint64
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var size uint64
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var shname string
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var typ uint64
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//nolint:revive
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const (
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DT_NULL = 0
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DT_NEEDED = 1
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DT_PLTRELSZ = 2
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DT_PLTGOT = 3
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DT_HASH = 4
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DT_STRTAB = 5
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DT_SYMTAB = 6
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DT_RELA = 7
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DT_RELASZ = 8
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DT_RELAENT = 9
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DT_STRSZ = 10
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DT_SYMENT = 11
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DT_INIT = 12
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DT_FINI = 13
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DT_SONAME = 14
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DT_RPATH = 15
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DT_SYMBOLIC = 16
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DT_REL = 17
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DT_RELSZ = 18
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DT_RELENT = 19
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DT_PLTREL = 20
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DT_DEBUG = 21
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DT_TEXTREL = 22
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DT_JMPREL = 23
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DT_ENCODING = 32
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)
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var dtNames = decode.UToStr{
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DT_NULL: "DT_NULL",
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DT_NEEDED: "DT_NEEDED",
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DT_PLTRELSZ: "DT_PLTRELSZ",
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DT_PLTGOT: "DT_PLTGOT",
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DT_HASH: "DT_HASH",
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DT_STRTAB: "DT_STRTAB",
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DT_SYMTAB: "DT_SYMTAB",
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DT_RELA: "DT_RELA",
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DT_RELASZ: "DT_RELASZ",
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DT_RELAENT: "DT_RELAENT",
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DT_STRSZ: "DT_STRSZ",
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DT_SYMENT: "DT_SYMENT",
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DT_INIT: "DT_INIT",
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DT_FINI: "DT_FINI",
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DT_SONAME: "DT_SONAME",
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DT_RPATH: "DT_RPATH",
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DT_SYMBOLIC: "DT_SYMBOLIC",
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DT_REL: "DT_REL",
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DT_RELSZ: "DT_RELSZ",
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DT_RELENT: "DT_RELENT",
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DT_PLTREL: "DT_PLTREL",
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DT_DEBUG: "DT_DEBUG",
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DT_TEXTREL: "DT_TEXTREL",
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DT_JMPREL: "DT_JMPREL",
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DT_ENCODING: "DT_ENCODING",
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}
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switch archBits {
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case 32:
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shname = d.FieldScalar("sh_name", d.ScalarU32(), mapStrTable(strIndexTable)).SymStr()
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typ = d.FieldU32("sh_type", d.MapUToStrSym(shTypeNames), d.Hex)
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shFlags(d, archBits)
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d.FieldU("sh_addr", archBits)
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offset = d.FieldU("sh_offset", archBits)
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size = d.FieldU32("sh_size")
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d.FieldU32("sh_link")
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d.FieldU32("sh_info")
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d.FieldU32("sh_addralign")
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d.FieldU32("sh_entsize")
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case 64:
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shname = d.FieldScalar("sh_name", d.ScalarU32(), mapStrTable(strIndexTable)).SymStr()
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typ = d.FieldU32("sh_type", d.MapUToStrSym(shTypeNames), d.Hex)
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shFlags(d, archBits)
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d.FieldU("sh_addr", archBits)
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offset = d.FieldU("sh_offset", archBits)
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size = d.FieldU64("sh_size")
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d.FieldU32("sh_link")
|
|
d.FieldU32("sh_info")
|
|
d.FieldU64("sh_addralign")
|
|
d.FieldU64("sh_entsize")
|
|
}
|
|
|
|
// SHT_NOBITS:
|
|
// "Identifies a section that occupies no space in the file but otherwise resembles SHT_PROGBITS. Although this section contains no bytes, the sh_offset member contains the conceptual file offset."
|
|
if typ != SHT_NOBITS {
|
|
d.RangeFn(int64(offset*8), int64(size*8), func(d *decode.D) {
|
|
d.FieldRawLen("data", d.BitsLeft())
|
|
})
|
|
|
|
d.RangeFn(int64(offset)*8, int64(size*8), func(d *decode.D) {
|
|
switch shname {
|
|
// TODO: PT_DYNAMIC?
|
|
case ".dynamic":
|
|
d.FieldArray("dynamic_tags", func(d *decode.D) {
|
|
for d.NotEnd() {
|
|
d.FieldStruct("tag", func(d *decode.D) {
|
|
tag := d.FieldUFn("tag", func(d *decode.D) uint64 { return d.U(archBits) }, d.MapUToStrSym(dtNames), d.Hex)
|
|
switch tag {
|
|
case DT_NEEDED:
|
|
// TODO: DT_STRTAB
|
|
//fieldStringStrIndexFn(d, "val", strIndexTable, func(d *decode.D) uint64 { return d.U(archBits) })
|
|
default:
|
|
d.FieldU("d_un", archBits)
|
|
}
|
|
})
|
|
}
|
|
})
|
|
}
|
|
})
|
|
}
|
|
})
|
|
}
|
|
})
|
|
// })
|
|
|
|
return nil
|
|
}
|