예제 #1
0
파일: elf_auxv.go 프로젝트: x56/usercorn
func setupElfAuxv(u models.Usercorn) ([]Elf64Auxv, error) {
	// set up AT_RANDOM
	var tmp [16]byte
	if _, err := rand.Read(tmp[:]); err != nil {
		return nil, err
	}
	randAddr, err := u.PushBytes(tmp[:])
	if err != nil {
		return nil, err
	}
	// insert platform string
	platformAddr, err := u.PushBytes([]byte(u.Loader().Arch() + "\x00"))
	if err != nil {
		return nil, err
	}
	// main auxv table
	auxv := []Elf64Auxv{
		// TODO: set/track a page size somewhere - on Arch.OS?
		{ELF_AT_PAGESZ, 4096},
		{ELF_AT_BASE, u.InterpBase()},
		{ELF_AT_FLAGS, 0},
		{ELF_AT_ENTRY, uint64(u.BinEntry())},
		{ELF_AT_UID, uint64(os.Getuid())},
		{ELF_AT_EUID, uint64(os.Geteuid())},
		{ELF_AT_GID, uint64(os.Getgid())},
		{ELF_AT_EGID, uint64(os.Getegid())},
		{ELF_AT_PLATFORM, platformAddr},
		{ELF_AT_CLKTCK, 100}, // 100hz, totally fake
		{ELF_AT_RANDOM, randAddr},
		{ELF_AT_NULL, 0},
	}
	// add phdr information if present in binary
	phdrOff, _, phdrCount := u.Loader().Header()
	segments, _ := u.Loader().Segments()
	for _, s := range segments {
		if s.ContainsPhys(phdrOff) {
			phdrOff += s.Addr
			break
		}
	}
	phdrEnt := 56
	if u.Bits() == 32 {
		phdrEnt = 56 // FIXME
	}
	if phdrOff > 0 {
		auxv = append(auxv, []Elf64Auxv{
			{ELF_AT_PHDR, phdrOff},
			{ELF_AT_PHENT, uint64(phdrEnt)},
			{ELF_AT_PHNUM, uint64(phdrCount)},
		}...)
	}
	return auxv, nil
}