예제 #1
0
func StackInit(u models.Usercorn, args, env []string, auxv []byte) error {
	// push argv and envp strings
	envp, err := pushStrings(u, env...)
	if err != nil {
		return err
	}
	argv, err := pushStrings(u, args...)
	if err != nil {
		return err
	}
	// align stack pointer
	sp, _ := u.RegRead(u.Arch().SP)
	u.RegWrite(u.Arch().SP, (sp & ^uint64(15)))
	// end marker
	if _, err := u.Push(0); err != nil {
		return err
	}
	// auxv
	if len(auxv) > 0 {
		if _, err := u.PushBytes(auxv); err != nil {
			return err
		}
	}
	// envp
	if err := pushAddrs(u, envp); err != nil {
		return err
	}
	// argv
	if err := pushAddrs(u, argv); err != nil {
		return err
	}
	// argc
	_, err = u.Push(uint64(len(args)))
	return err
}
예제 #2
0
func pushStrings(u models.Usercorn, args ...string) ([]uint64, error) {
	addrs := make([]uint64, 0, len(args)+1)
	for _, arg := range args {
		if addr, err := u.PushBytes([]byte(arg + "\x00")); err != nil {
			return nil, err
		} else {
			addrs = append(addrs, addr)
		}
	}
	return addrs, nil
}
예제 #3
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
}
예제 #4
0
func StackInit(u models.Usercorn, args, env []string) error {
	exe := u.Exe()
	addr, err := u.PushBytes([]byte(exe + "\x00"))
	if err != nil {
		return err
	}
	var tmp [8]byte
	auxv, err := u.PackAddr(tmp[:], addr)
	if err != nil {
		return err
	}
	err = posix.StackInit(u, args, env, auxv)
	if err != nil {
		return err
	}
	// offset to mach_header at exe[0:] in guest memory
	textOffset, _, _ := u.Loader().Header()
	offset := u.Base() + textOffset
	_, err = u.Push(offset)
	return err
}
예제 #5
0
func StackInit(u models.Usercorn, args, env []string, auxv []byte) error {
	if _, err := u.Push(0); err != nil {
		return err
	}
	if len(args) > 0 {
		if _, err := u.PushBytes([]byte(args[0] + "\x00")); err != nil {
			return err
		}
	}
	// push argv and envp strings
	envp, err := pushStrings(u, env...)
	if err != nil {
		return err
	}
	argv, err := pushStrings(u, args...)
	if err != nil {
		return err
	}
	// precalc envp -> argc for stack alignment
	envpb, err := packAddrs(u, envp)
	if err != nil {
		return err
	}
	argvb, err := packAddrs(u, argv)
	if err != nil {
		return err
	}
	var tmp [8]byte
	argcb, err := u.PackAddr(tmp[:], uint64(len(argv)))
	init := append(argcb, argvb...)
	init = append(init, envpb...)
	// align stack pointer
	sp, _ := u.RegRead(u.Arch().SP)
	sp &= ^uint64(15)
	off := len(init) & 15
	if off > 0 {
		sp -= uint64(16 - off)
	}
	u.RegWrite(u.Arch().SP, sp)
	// auxv
	if len(auxv) > 0 {
		if _, err := u.PushBytes(auxv); err != nil {
			return err
		}
	}
	// write envp -> argc
	u.PushBytes(init)
	return err
}