1"use strict"; 2/* DokuWiki BotMon Captcha JavaScript */ 3/* 22.10.2025 - 0.1.0 - pre-release */ 4/* Author: Sascha Leib <ad@hominem.info> */ 5 6const $BMCaptcha = { 7 8 init: function() { 9 /* mark the page to contain the captcha styles */ 10 document.getElementsByTagName('body')[0].classList.add('botmon_captcha'); 11 12 $BMCaptcha.install() 13 }, 14 15 install: function() { 16 // find the parent element: 17 let bm_parent = document.getElementsByTagName('body')[0]; 18 19 // create the dialog: 20 const dlg = document.createElement('dialog'); 21 dlg.setAttribute('closedby', 'none'); 22 dlg.setAttribute('open', 'open'); 23 dlg.id = 'botmon_captcha_box'; 24 dlg.innerHTML = '<h2>Captcha box</h2><p>Checking if you are a human …</p><p></p>'; 25 26 // Checkbox: 27 const lbl = document.createElement('label'); 28 const cb = document.createElement('input'); 29 cb.setAttribute('type', 'checkbox'); 30 cb.addEventListener('click', $BMCaptcha._cbCallback); 31 lbl.appendChild(cb); 32 lbl.appendChild(document.createTextNode('I am a human.')); 33 34 dlg.appendChild(lbl); 35 36 bm_parent.appendChild(dlg); 37 }, 38 39 /* creates a digest hash for the cookie function */ 40 digest: { 41 42 /* simple SHA hash function - adapted from https://geraintluff.github.io/sha256/ */ 43 hash: function(ascii) { 44 45 // shortcut: 46 const sha256 = $BMCaptcha.digest.hash; 47 48 // helper function 49 const rightRotate = function(v, a) { 50 return (v>>>a) | (v<<(32 - a)); 51 }; 52 53 var mathPow = Math.pow; 54 var maxWord = mathPow(2, 32); 55 var lengthProperty = 'length' 56 var i, j; 57 var result = '' 58 59 var words = []; 60 var asciiBitLength = ascii[lengthProperty]*8; 61 62 //* caching results is optional - remove/add slash from front of this line to toggle 63 // Initial hash value: first 32 bits of the fractional parts of the square roots of the first 8 primes 64 // (we actually calculate the first 64, but extra values are just ignored) 65 var hash = sha256.h = sha256.h || []; 66 // Round constants: first 32 bits of the fractional parts of the cube roots of the first 64 primes 67 var k = sha256.k = sha256.k || []; 68 var primeCounter = k[lengthProperty]; 69 /*/ 70 var hash = [], k = []; 71 var primeCounter = 0; 72 //*/ 73 74 var isComposite = {}; 75 for (var candidate = 2; primeCounter < 64; candidate++) { 76 if (!isComposite[candidate]) { 77 for (i = 0; i < 313; i += candidate) { 78 isComposite[i] = candidate; 79 } 80 hash[primeCounter] = (mathPow(candidate, .5)*maxWord)|0; 81 k[primeCounter++] = (mathPow(candidate, 1/3)*maxWord)|0; 82 } 83 } 84 85 ascii += '\x80' // Append Ƈ' bit (plus zero padding) 86 while (ascii[lengthProperty]%64 - 56) ascii += '\x00' // More zero padding 87 for (i = 0; i < ascii[lengthProperty]; i++) { 88 j = ascii.charCodeAt(i); 89 if (j>>8) return; // ASCII check: only accept characters in range 0-255 90 words[i>>2] |= j << ((3 - i)%4)*8; 91 } 92 words[words[lengthProperty]] = ((asciiBitLength/maxWord)|0); 93 words[words[lengthProperty]] = (asciiBitLength) 94 95 // process each chunk 96 for (j = 0; j < words[lengthProperty];) { 97 var w = words.slice(j, j += 16); // The message is expanded into 64 words as part of the iteration 98 var oldHash = hash; 99 // This is now the undefinedworking hash", often labelled as variables a...g 100 // (we have to truncate as well, otherwise extra entries at the end accumulate 101 hash = hash.slice(0, 8); 102 103 for (i = 0; i < 64; i++) { 104 var i2 = i + j; 105 // Expand the message into 64 words 106 // Used below if 107 var w15 = w[i - 15], w2 = w[i - 2]; 108 109 // Iterate 110 var a = hash[0], e = hash[4]; 111 var temp1 = hash[7] 112 + (rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25)) // S1 113 + ((e&hash[5])^((~e)&hash[6])) // ch 114 + k[i] 115 // Expand the message schedule if needed 116 + (w[i] = (i < 16) ? w[i] : ( 117 w[i - 16] 118 + (rightRotate(w15, 7) ^ rightRotate(w15, 18) ^ (w15>>>3)) // s0 119 + w[i - 7] 120 + (rightRotate(w2, 17) ^ rightRotate(w2, 19) ^ (w2>>>10)) // s1 121 )|0 122 ); 123 // This is only used once, so *could* be moved below, but it only saves 4 bytes and makes things unreadble 124 var temp2 = (rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22)) // S0 125 + ((a&hash[1])^(a&hash[2])^(hash[1]&hash[2])); // maj 126 127 hash = [(temp1 + temp2)|0].concat(hash); // We don't bother trimming off the extra ones, they're harmless as long as we're truncating when we do the slice() 128 hash[4] = (hash[4] + temp1)|0; 129 } 130 131 for (i = 0; i < 8; i++) { 132 hash[i] = (hash[i] + oldHash[i])|0; 133 } 134 } 135 136 for (i = 0; i < 8; i++) { 137 for (j = 3; j + 1; j--) { 138 var b = (hash[i]>>(j*8))&255; 139 result += ((b < 16) ? 0 : '') + b.toString(16); 140 } 141 } 142 return result; 143 } 144 }, 145 146 _cbCallback: function(e) { 147 if (e.target.checked) { 148 //document.getElementById('botmon_captcha_box').close(); 149 150 // make a hash for the cookie: 151 const seed = document._botmon.seed || ''; 152 const extIp = document._botmon.ip || '0.0.0.0'; 153 const d = new Date(document._botmon.t0); 154 const raw = seed + '|' + location.hostname + '|' + extIp + '|' + d.toISOString().substring(0, 10); 155 156 const hash = $BMCaptcha.digest.hash(raw); 157 console.log('Setting cookie to:', raw, ' --> ', hash); 158 document.cookie = "captcha=" + hash + ';'; 159 160 window.location.reload(true); 161 } 162 } 163 164} 165// initialise the captcha module: 166$BMCaptcha.init();