timing-attack.js (1402B)
1 function run_test(isolated) { 2 let resolution = 100; 3 if (isolated) { 4 resolution = 5; 5 } 6 test(function() { 7 function check_resolutions(times, length) { 8 const end = length - 2; 9 10 // we compare each value with the following ones 11 for (let i = 0; i < end; i++) { 12 const h1 = times[i]; 13 for (let j = i+1; j < end; j++) { 14 const h2 = times[j]; 15 const diff = h2 - h1; 16 assert_true((diff === 0) || ((diff * 1000) >= resolution), 17 "Differences smaller than ' + resolution + ' microseconds: " + diff); 18 } 19 } 20 return true; 21 } 22 23 const times = new Array(10); 24 let index = 0; 25 let hrt1, hrt2, hrt; 26 assert_equals(self.crossOriginIsolated, isolated, "Document cross-origin isolated value matches"); 27 28 // rapid firing of performance.now 29 hrt1 = performance.now(); 30 hrt2 = performance.now(); 31 times[index++] = hrt1; 32 times[index++] = hrt2; 33 34 // ensure that we get performance.now() to return a different value 35 do { 36 hrt = performance.now(); 37 times[index++] = hrt; 38 } while ((hrt - hrt1) === 0); 39 40 assert_true(check_resolutions(times, index), 'Difference should be at least ' + resolution + ' microseconds.'); 41 }, 'The recommended minimum resolution of the Performance interface has been set to ' + resolution + ' microseconds for cross-origin isolated contexts.'); 42 }