https://github.com/idouble/nasm-assembly-linux-notes

🐧 Assembly with Linux (Notes, Syscalls, Protection Rings) 🐧
https://github.com/idouble/nasm-assembly-linux-notes
assembly kernel-mode kernel-module linux linux-kernel nasm nasm-assembly privilege-levels privileged-instruction protection-ring read ring-0 ring-3 ring0 ring3 syscalls systemcall systemcalls usermode write
Last synced: about 1 year ago
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🐧 Assembly with Linux (Notes, Syscalls, Protection Rings) 🐧
Host: GitHub
URL: https://github.com/idouble/nasm-assembly-linux-notes
Owner: IDouble
License: mit
Created: 2019-12-25T08:09:35.000Z (over 6 years ago)
Default Branch: master
Last Pushed: 2024-02-29T17:13:52.000Z (about 2 years ago)
Last Synced: 2025-04-07T10:54:05.251Z (about 1 year ago)
Topics: assembly, kernel-mode, kernel-module, linux, linux-kernel, nasm, nasm-assembly, privilege-levels, privileged-instruction, protection-ring, read, ring-0, ring-3, ring0, ring3, syscalls, systemcall, systemcalls, usermode, write
Language: Assembly
Homepage:
Size: 2.24 MB
Stars: 115
Watchers: 5
Forks: 13
Open Issues: 1
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project

README

          # 🐧 NASM Assembly Linux Notes 🐧

🐧 Assembly with **Linux** (Notes, **Syscalls**, **Protection Rings**) 🐧

## 🐧 System Calls Linux (Syscalls) 🐧

![System Calls Linux Assembly NASM ASM](Images/systemcalls_linux_kernel.png)

### ❓ What is a System Call? ❓

When you run a program which calls **open, fork, read, write** (and many others) you are making a **System Call**.

**System Calls** are how a program enters the kernel to perform some task. Programs use **System Calls** to perform a variety of operations such as: **creating processes, doing network and file IO**, and much more.

Example: A user running a word processor in **User Mode (Ring 3)** presses “save”: a **System Call** is made into **Kernel Mode (Ring 0)**, asking the **Kernel** to save the file.

## 📖 System Call Table (Syscall Table) 📖

 

 

 

 

 

 

 

 

 

 

  #

  Name

  Registers

  

  

 

 

  eax

  ebx

  ecx

  edx

  esi

  edi

  

 

 

  0

  sys_restart_syscall

  0x00

  -

  -

  -

  -

  -

  

 

 

  1

  sys_exit

  0x01

  int error_code

  -

  -

  -

  -

  

 

 

  2

  sys_fork

  0x02

  struct pt_regs *

  -

  -

  -

  -

  

 

 

  3

  sys_read

  0x03

  unsigned int fd

  char __user *buf

  size_t count

  -

  -

  

 

 

  4

  sys_write

  0x04

  unsigned int fd

  const char __user *buf

  size_t count

  -

  -

  

 

 

  5

  sys_open

  0x05

  const char __user *filename

  int flags

  int mode

  -

  -

  

 

 

  6

  sys_close

  0x06

  unsigned int fd

  -

  -

  -

  -

  

 

 

  7

  sys_waitpid

  0x07

  pid_t pid

  int __user *stat_addr

  int options

  -

  -

  

 

 

  8

  sys_creat

  0x08

  const char __user *pathname

  int mode

  -

  -

  -

  

 

 

  9

  sys_link

  0x09

  const char __user *oldname

  const char __user *newname

  -

  -

  -

  

 

 

  10

  sys_unlink

  0x0a

  const char __user *pathname

  -

  -

  -

  -

  

 

 

  11

  sys_execve

  0x0b

  char __user *

  char __user *__user *

  char __user *__user *

  struct pt_regs *

  -

  

 

 

  12

  sys_chdir

  0x0c

  const char __user *filename

  -

  -

  -

  -

  

 

 

  13

  sys_time

  0x0d

  time_t __user *tloc

  -

  -

  -

  -

  

 

 

  14

  sys_mknod

  0x0e

  const char __user *filename

  int mode

  unsigned dev

  -

  -

  

 

 

  15

  sys_chmod

  0x0f

  const char __user *filename

  mode_t mode

  -

  -

  -

  

 

 

  16

  sys_lchown16

  0x10

  const char __user *filename

  old_uid_t user

  old_gid_t group

  -

  -

  

 

 

  17

  not implemented

  0x11

  -

  -

  -

  -

  -

  

 

 

  18

  sys_stat

  0x12

  char __user *filename

  struct __old_kernel_stat __user *statbuf

  -

  -

  -

  

 

 

  19

  sys_lseek

  0x13

  unsigned int fd

  off_t offset

  unsigned int origin

  -

  -

  

 

 

  20

  sys_getpid

  0x14

  -

  -

  -

  -

  -

  

 

 

  21

  sys_mount

  0x15

  char __user *dev_name

  char __user *dir_name

  char __user *type

  unsigned long flags

  void __user *data

  

 

 

  22

  sys_oldumount

  0x16

  char __user *name

  -

  -

  -

  -

  

 

 

  23

  sys_setuid16

  0x17

  old_uid_t uid

  -

  -

  -

  -

  

 

 

  24

  sys_getuid16

  0x18

  -

  -

  -

  -

  -

  

 

 

  25

  sys_stime

  0x19

  time_t __user *tptr

  -

  -

  -

  -

  

 

 

  26

  sys_ptrace

  0x1a

  long request

  long pid

  long addr

  long data

  -

  

 

 

  27

  sys_alarm

  0x1b

  unsigned int seconds

  -

  -

  -

  -

  

 

 

  28

  sys_fstat

  0x1c

  unsigned int fd

  struct __old_kernel_stat __user *statbuf

  -

  -

  -

  

 

 

  29

  sys_pause

  0x1d

  -

  -

  -

  -

  -

  

 

 

  30

  sys_utime

  0x1e

  char __user *filename

  struct utimbuf __user *times

  -

  -

  -

  

 

 

  31

  not implemented

  0x1f

  -

  -

  -

  -

  -

  

 

 

  32

  not implemented

  0x20

  -

  -

  -

  -

  -

  

 

 

  33

  sys_access

  0x21

  const char __user *filename

  int mode

  -

  -

  -

  

 

 

  34

  sys_nice

  0x22

  int increment

  -

  -

  -

  -

  

 

 

  35

  not implemented

  0x23

  -

  -

  -

  -

  -

  

 

 

  36

  sys_sync

  0x24

  -

  -

  -

  -

  -

  

 

 

  37

  sys_kill

  0x25

  int pid

  int sig

  -

  -

  -

  

 

 

  38

  sys_rename

  0x26

  const char __user *oldname

  const char __user *newname

  -

  -

  -

  

 

 

  39

  sys_mkdir

  0x27

  const char __user *pathname

  int mode

  -

  -

  -

  

 

 

  40

  sys_rmdir

  0x28

  const char __user *pathname

  -

  -

  -

  -

  

 

 

  41

  sys_dup

  0x29

  unsigned int fildes

  -

  -

  -

  -

  

 

 

  42

  sys_pipe

  0x2a

  int __user *fildes

  -

  -

  -

  -

  

 

 

  43

  sys_times

  0x2b

  struct tms __user *tbuf

  -

  -

  -

  -

  

 

 

  44

  not implemented

  0x2c

  -

  -

  -

  -

  -

  

 

 

  45

  sys_brk

  0x2d

  unsigned long brk

  -

  -

  -

  -

  

 

 

  46

  sys_setgid16

  0x2e

  old_gid_t gid

  -

  -

  -

  -

  

 

 

  47

  sys_getgid16

  0x2f

  -

  -

  -

  -

  -

  

 

 

  48

  sys_signal

  0x30

  int sig

  __sighandler_t handler

  -

  -

  -

  

 

 

  49

  sys_geteuid16

  0x31

  -

  -

  -

  -

  -

  

 

 

  50

  sys_getegid16

  0x32

  -

  -

  -

  -

  -

  

 

 

  51

  sys_acct

  0x33

  const char __user *name

  -

  -

  -

  -

  

 

 

  52

  sys_umount

  0x34

  char __user *name

  int flags

  -

  -

  -

  

 

 

  53

  not implemented

  0x35

  -

  -

  -

  -

  -

  

 

 

  54

  sys_ioctl

  0x36

  unsigned int fd

  unsigned int cmd

  unsigned long arg

  -

  -

  

 

 

  55

  sys_fcntl

  0x37

  unsigned int fd

  unsigned int cmd

  unsigned long arg

  -

  -

  

 

 

  56

  not implemented

  0x38

  -

  -

  -

  -

  -

  

 

 

  57

  sys_setpgid

  0x39

  pid_t pid

  pid_t pgid

  -

  -

  -

  

 

 

  58

  not implemented

  0x3a

  -

  -

  -

  -

  -

  

 

 

  59

  sys_olduname

  0x3b

  struct oldold_utsname __user *

  -

  -

  -

  -

  

 

 

  60

  sys_umask

  0x3c

  int mask

  -

  -

  -

  -

  

 

 

  61

  sys_chroot

  0x3d

  const char __user *filename

  -

  -

  -

  -

  

 

 

  62

  sys_ustat

  0x3e

  unsigned dev

  struct ustat __user *ubuf

  -

  -

  -

  

 

 

  63

  sys_dup2

  0x3f

  unsigned int oldfd

  unsigned int newfd

  -

  -

  -

  

 

 

  64

  sys_getppid

  0x40

  -

  -

  -

  -

  -

  

 

 

  65

  sys_getpgrp

  0x41

  -

  -

  -

  -

  -

  

 

 

  66

  sys_setsid

  0x42

  -

  -

  -

  -

  -

  

 

 

  67

  sys_sigaction

  0x43

  int sig

  const struct old_sigaction __user *act

  struct old_sigaction __user *oact

  -

  -

  

 

 

  68

  sys_sgetmask

  0x44

  -

  -

  -

  -

  -

  

 

 

  69

  sys_ssetmask

  0x45

  int newmask

  -

  -

  -

  -

  

 

 

  70

  sys_setreuid16

  0x46

  old_uid_t ruid

  old_uid_t euid

  -

  -

  -

  

 

 

  71

  sys_setregid16

  0x47

  old_gid_t rgid

  old_gid_t egid

  -

  -

  -

  

 

 

  72

  sys_sigsuspend

  0x48

  int history0

  int history1

  old_sigset_t mask

  -

  -

  

 

 

  73

  sys_sigpending

  0x49

  old_sigset_t __user *set

  -

  -

  -

  -

  

 

 

  74

  sys_sethostname

  0x4a

  char __user *name

  int len

  -

  -

  -

  

 

 

  75

  sys_setrlimit

  0x4b

  unsigned int resource

  struct rlimit __user *rlim

  -

  -

  -

  

 

 

  76

  sys_old_getrlimit

  0x4c

  unsigned int resource

  struct rlimit __user *rlim

  -

  -

  -

  

 

 

  77

  sys_getrusage

  0x4d

  int who

  struct rusage __user *ru

  -

  -

  -

  

 

 

  78

  sys_gettimeofday

  0x4e

  struct timeval __user *tv

  struct timezone __user *tz

  -

  -

  -

  

 

 

  79

  sys_settimeofday

  0x4f

  struct timeval __user *tv

  struct timezone __user *tz

  -

  -

  -

  

 

 

  80

  sys_getgroups16

  0x50

  int gidsetsize

  old_gid_t __user *grouplist

  -

  -

  -

  

 

 

  81

  sys_setgroups16

  0x51

  int gidsetsize

  old_gid_t __user *grouplist

  -

  -

  -

  

 

 

  82

  sys_old_select

  0x52

  struct sel_arg_struct __user *arg

  -

  -

  -

  -

  

 

 

  83

  sys_symlink

  0x53

  const char __user *old

  const char __user *new

  -

  -

  -

  

 

 

  84

  sys_lstat

  0x54

  char __user *filename

  struct __old_kernel_stat __user *statbuf

  -

  -

  -

  

 

 

  85

  sys_readlink

  0x55

  const char __user *path

  char __user *buf

  int bufsiz

  -

  -

  

 

 

  86

  sys_uselib

  0x56

  const char __user *library

  -

  -

  -

  -

  

 

 

  87

  sys_swapon

  0x57

  const char __user *specialfile

  int swap_flags

  -

  -

  -

  

 

 

  88

  sys_reboot

  0x58

  int magic1

  int magic2

  unsigned int cmd

  void __user *arg

  -

  

 

 

  89

  sys_old_readdir

  0x59

  unsigned int

  struct old_linux_dirent __user *

  unsigned int

  -

  -

  

 

 

  90

  sys_old_mmap

  0x5a

  struct mmap_arg_struct __user *arg

  -

  -

  -

  -

  

 

 

  91

  sys_munmap

  0x5b

  unsigned long addr

  size_t len

  -

  -

  -

  

 

 

  92

  sys_truncate

  0x5c

  const char __user *path

  long length

  -

  -

  -

  

 

 

  93

  sys_ftruncate

  0x5d

  unsigned int fd

  unsigned long length

  -

  -

  -

  

 

 

  94

  sys_fchmod

  0x5e

  unsigned int fd

  mode_t mode

  -

  -

  -

  

 

 

  95

  sys_fchown16

  0x5f

  unsigned int fd

  old_uid_t user

  old_gid_t group

  -

  -

  

 

 

  96

  sys_getpriority

  0x60

  int which

  int who

  -

  -

  -

  

 

 

  97

  sys_setpriority

  0x61

  int which

  int who

  int niceval

  -

  -

  

 

 

  98

  not implemented

  0x62

  -

  -

  -

  -

  -

  

 

 

  99

  sys_statfs

  0x63

  const char __user * path

  struct statfs __user *buf

  -

  -

  -

  

 

 

  100

  sys_fstatfs

  0x64

  unsigned int fd

  struct statfs __user *buf

  -

  -

  -

  

 

 

  101

  sys_ioperm

  0x65

  unsigned long

  unsigned long

  int

  -

  -

  

 

 

  102

  sys_socketcall

  0x66

  int call

  unsigned long __user *args

  -

  -

  -

  

 

 

  103

  sys_syslog

  0x67

  int type

  char __user *buf

  int len

  -

  -

  

 

 

  104

  sys_setitimer

  0x68

  int which

  struct itimerval __user *value

  struct itimerval __user *ovalue

  -

  -

  

 

 

  105

  sys_getitimer

  0x69

  int which

  struct itimerval __user *value

  -

  -

  -

  

 

 

  106

  sys_newstat

  0x6a

  char __user *filename

  struct stat __user *statbuf

  -

  -

  -

  

 

 

  107

  sys_newlstat

  0x6b

  char __user *filename

  struct stat __user *statbuf

  -

  -

  -

  

 

 

  108

  sys_newfstat

  0x6c

  unsigned int fd

  struct stat __user *statbuf

  -

  -

  -

  

 

 

  109

  sys_uname

  0x6d

  struct old_utsname __user *

  -

  -

  -

  -

  

 

 

  110

  sys_iopl

  0x6e

  unsigned int

  struct pt_regs *

  -

  -

  -

  

 

 

  111

  sys_vhangup

  0x6f

  -

  -

  -

  -

  -

  

 

 

  112

  not implemented

  0x70

  -

  -

  -

  -

  -

  

 

 

  113

  sys_vm86old

  0x71

  struct vm86_struct __user *

  struct pt_regs *

  -

  -

  -

  

 

 

  114

  sys_wait4

  0x72

  pid_t pid

  int __user *stat_addr

  int options

  struct rusage __user *ru

  -

  

 

 

  115

  sys_swapoff

  0x73

  const char __user *specialfile

  -

  -

  -

  -

  

 

 

  116

  sys_sysinfo

  0x74

  struct sysinfo __user *info

  -

  -

  -

  -

  

 

 

  117

  sys_ipc

  0x75

  -

  -

  -

  -

  -

  

 

 

  118

  sys_fsync

  0x76

  unsigned int fd

  -

  -

  -

  -

  

 

 

  119

  sys_sigreturn

  0x77

  struct pt_regs *regs

  -

  -

  -

  -

  

 

 

  120

  sys_clone

  0x78

  unsigned long

  unsigned long

  unsigned long

  unsigned long

  struct pt_regs *

  

 

 

  121

  sys_setdomainname

  0x79

  char __user *name

  int len

  -

  -

  -

  

 

 

  122

  sys_newuname

  0x7a

  struct new_utsname __user *name

  -

  -

  -

  -

  

 

 

  123

  sys_modify_ldt

  0x7b

  int

  void __user *

  unsigned long

  -

  -

  

 

 

  124

  sys_adjtimex

  0x7c

  struct timex __user *txc_p

  -

  -

  -

  -

  

 

 

  125

  sys_mprotect

  0x7d

  unsigned long start

  size_t len

  unsigned long prot

  -

  -

  

 

 

  126

  sys_sigprocmask

  0x7e

  int how

  old_sigset_t __user *set

  old_sigset_t __user *oset

  -

  -

  

 

 

  127

  not implemented

  0x7f

  -

  -

  -

  -

  -

  

 

 

  128

  sys_init_module

  0x80

  void __user *umod

  unsigned long len

  const char __user *uargs

  -

  -

  

 

 

  129

  sys_delete_module

  0x81

  const char __user *name_user

  unsigned int flags

  -

  -

  -

  

 

 

  130

  not implemented

  0x82

  -

  -

  -

  -

  -

  

 

 

  131

  sys_quotactl

  0x83

  unsigned int cmd

  const char __user *special

  qid_t id

  void __user *addr

  -

  

 

 

  132

  sys_getpgid

  0x84

  pid_t pid

  -

  -

  -

  -

  

 

 

  133

  sys_fchdir

  0x85

  unsigned int fd

  -

  -

  -

  -

  

 

 

  134

  sys_bdflush

  0x86

  int func

  long data

  -

  -

  -

  

 

 

  135

  sys_sysfs

  0x87

  int option

  unsigned long arg1

  unsigned long arg2

  -

  -

  

 

 

  136

  sys_personality

  0x88

  unsigned int personality

  -

  -

  -

  -

  

 

 

  137

  not implemented

  0x89

  -

  -

  -

  -

  -

  

 

 

  138

  sys_setfsuid16

  0x8a

  old_uid_t uid

  -

  -

  -

  -

  

 

 

  139

  sys_setfsgid16

  0x8b

  old_gid_t gid

  -

  -

  -

  -

  

 

 

  140

  sys_llseek

  0x8c

  unsigned int fd

  unsigned long offset_high

  unsigned long offset_low

  loff_t __user *result

  unsigned int origin

  

 

 

  141

  sys_getdents

  0x8d
ecosyste.ms

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