/* binary (ELF) to shellcode converter */
/* by Dalnet SLACKo  slacko@mail.ru    */
#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <linux/elf.h>
  int main(int argc,char **argv) {
    Elf32_Ehdr _ehdr;
    Elf32_Shdr _shdr;
    struct stat _info;
    unsigned long _mapped;
    unsigned long _offset;
    int fd,i,_shnum;
    int _nextsize = 0;
    stat(argv[1],&_info);
    if(argc!=2) { 
    fprintf(stderr,"Usage %s <binary-file>\n",argv[0]);
    exit(1);
      }
    if((fd = open(argv[1],O_RDWR,0)) == -1) {
      perror("open()");
      exit(1);
      }
    (void *)_mapped = mmap(0,_info.st_size,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);
    if( *(long *)_mapped !=  (long)0x464c457f)  {
      fprintf(stderr,"File is not an ELF binary file\n");
      exit(1);
      }
    _ehdr = *(Elf32_Ehdr *)_mapped;
    _shnum = _ehdr.e_shnum;
    _shdr = *(Elf32_Shdr *)(_mapped + _ehdr.e_shoff);
    _offset = _ehdr.e_entry - 0x08048000;
    for(i=0;i<_shnum;i++) {
      if(_shdr.sh_offset == _offset) 
        break; 
      else {
      _nextsize += sizeof(Elf32_Shdr); 
      _shdr = *(Elf32_Shdr *)(_mapped + _ehdr.e_shoff + _nextsize);
      }
      }
    printf("Shellcode size %d bytes\n",_shdr.sh_size);
    for(i=0;i<_shdr.sh_size;i++) {
      if(!(i % 10) && i!=0) 
      printf("\"\n\"");
      if(i == 0) 
      printf("\n\"");
    printf("\\x%x",*(unsigned char *)(_mapped + _offset + i));
      }
    printf("\"\n\n");
    munmap((void *)_mapped,_info.st_size);
    close(fd);
    }