I wrote assembly code to test the shellcode example. However, I got the following errors when I compile assembly code. I've tried to compile assembly code as .S and .s too. also, I tried to compile as "gcc -nostdlib -static shellcode.s -o shellcode-elf" and "as shellcode.s -o shellcode.o" too.
Can anyone please help me with compiling simple assembly code on by Ubuntu ?(Using mac M1 chip)
uname -a :
Linux ubuntu 5.8.0-49-generic #55~20.04.1-Ubuntu SMP Fri Mar 26 01:00:41 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux
Errors:
shellcode.s: Assembler messages:
shellcode.s:6: Error: operand 1 must be an integer register -- `mov rax,59'
shellcode.s:7: Error: unknown mnemonic `lea' -- `lea rdi,[rip+binsh]'
shellcode.s:8: Error: operand 1 must be an integer register -- `mov rsi,0'
shellcode.s:9: Error: operand 1 must be an integer register -- `mov rdx,0'
shellcode.s:10: Error: unknown mnemonic `syscall' -- `syscall'
Assembly code:
global _start
_start:
xor %eax, %eax
xor %edx, %edx
push %eax
push $0x68732f2f
push $0x6e69622f
mov %esp, %ebx
push %edx
push %ebx
mov %esp, %ecx
movb $0x0B, %al
int $0x80
As pointed-out in the comments, you can compile/execute programs targeting x86-64 Linux on a AArch64 Linux system using a cross-compiler and an emulator such as qemu-user.
Please note that the program will not be natively executed though. This should however be sufficient for your needs.
This example was built on a Aarch64 Ubuntu 20.04 system:
uname -a
Linux orangepipc2 5.10.21-sunxi64 #21.02.3 SMP Mon Mar 8 00:45:13 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux
# install the cross-compiler and qemu-user
sudo apt-get install gcc-10-multilib-x86-64-linux-gnu
sudo apt-get install qemu-user
Create hello.s (credits: https://cs.lmu.edu/~ray/notes/gasexamples/), since the code you provided does not assemble properly. Pointing-out why is out of the scope of the current answer - you should be able to fix the code by yourself once you will have the x86-64 cross-compiler installed.
hello.s:
.global main
.text
main:
# write(1, message, 13)
mov $1, %rax # system call 1 is write
mov $1, %rdi # file handle 1 is stdout
mov $message, %rsi # address of string to output
mov $13, %rdx # number of bytes
syscall # invoke operating system to do the write
# exit(0)
mov $60, %rax # system call 60 is exit
xor %rdi, %rdi # we want return code 0
syscall # invoke operating system to exit
message:
.ascii "Hello, world\n"
/usr/bin/x86_64-linux-gnu-gcc-10 -static -o hello hello.s
file hello
hello: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, BuildID[sha1]=2fb401aedb8c9593ea93c0c2dd59b91f11b57b10, for GNU/Linux 3.2.0, not stripped
qemu-x86_64 hello
Hello, world