Merge branch 'staging' of github.com:xwiki-labs/cryptpad into staging
yflory
8 years ago
commit
fc760b4820
@ -0,0 +1,182 @@
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define([
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'/bower_components/tweetnacl/nacl-fast.min.js',
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], function () {
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var Nacl = window.nacl;
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var PARANOIA = true;
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var plainChunkLength = 128 * 1024;
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var cypherChunkLength = 131088;
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var slice = function (A) {
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return Array.prototype.slice.call(A);
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};
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var createNonce = function () {
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return new Uint8Array(new Array(24).fill(0));
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};
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var increment = function (N) {
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var l = N.length;
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while (l-- > 1) {
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if (PARANOIA) {
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if (typeof(N[l]) !== 'number') {
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throw new Error('E_UNSAFE_TYPE');
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}
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if (N[l] > 255) {
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throw new Error('E_OUT_OF_BOUNDS');
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}
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}
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/* jshint probably suspects this is unsafe because we lack types
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but as long as this is only used on nonces, it should be safe */
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if (N[l] !== 255) { return void N[l]++; } // jshint ignore:line
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N[l] = 0;
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// you don't need to worry about this running out.
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// you'd need a REAAAALLY big file
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if (l === 0) { return true; }
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}
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};
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var joinChunks = function (chunks) {
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return new Uint8Array(chunks.reduce(function (A, B) {
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return slice(A).concat(slice(B));
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}, []));
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};
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var padChunk = function (A) {
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var padding;
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if (A.length === plainChunkLength) { return A; }
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if (A.length < plainChunkLength) {
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padding = new Array(plainChunkLength - A.length).fill(32);
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return A.concat(padding);
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}
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if (A.length > plainChunkLength) {
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// how many times larger is it?
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var chunks = Math.ceil(A.length / plainChunkLength);
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padding = new Array((plainChunkLength * chunks) - A.length).fill(32);
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return A.concat(padding);
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}
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};
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var decrypt = function (u8, key, cb) {
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var nonce = createNonce();
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var i = 0;
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var takeChunk = function () {
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var start = i * cypherChunkLength;
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var end = start + cypherChunkLength;
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i++;
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var box = new Uint8Array(u8.subarray(start, end));
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// decrypt the chunk
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var plaintext = Nacl.secretbox.open(box, nonce, key);
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// TODO handle nonce-too-large-error
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increment(nonce);
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return plaintext;
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};
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var buffer = '';
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var res = {
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metadata: undefined,
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};
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// decrypt metadata
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var chunk;
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for (; !res.metadata && i * cypherChunkLength < u8.length;) {
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chunk = takeChunk();
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buffer += Nacl.util.encodeUTF8(chunk);
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try {
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res.metadata = JSON.parse(buffer);
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//console.log(res.metadata);
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} catch (e) {
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console.log('buffering another chunk for metadata');
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}
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}
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if (!res.metadata) {
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return void setTimeout(function () {
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cb('NO_METADATA');
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});
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}
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var fail = function () {
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cb("DECRYPTION_ERROR");
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};
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var chunks = [];
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// decrypt file contents
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for (;i * cypherChunkLength < u8.length;) {
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chunk = takeChunk();
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if (!chunk) {
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return window.setTimeout(fail);
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}
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chunks.push(chunk);
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}
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// send chunks
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res.content = joinChunks(chunks);
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cb(void 0, res);
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};
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// metadata
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/* { filename: 'raccoon.jpg', type: 'image/jpeg' } */
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/* TODO
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in your callback, return an object which you can iterate...
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*/
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var encrypt = function (u8, metadata, key, cb) {
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var nonce = createNonce();
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// encode metadata
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var metaBuffer = Array.prototype.slice
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.call(Nacl.util.decodeUTF8(JSON.stringify(metadata)));
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var plaintext = new Uint8Array(padChunk(metaBuffer));
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var chunks = [];
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var j = 0;
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var start;
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var end;
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var part;
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var box;
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// prepend some metadata
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for (;j * plainChunkLength < plaintext.length; j++) {
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start = j * plainChunkLength;
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end = start + plainChunkLength;
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part = plaintext.subarray(start, end);
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box = Nacl.secretbox(part, nonce, key);
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chunks.push(box);
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increment(nonce);
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}
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// append the encrypted file chunks
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var i = 0;
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for (;i * plainChunkLength < u8.length; i++) {
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start = i * plainChunkLength;
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end = start + plainChunkLength;
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part = new Uint8Array(u8.subarray(start, end));
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box = Nacl.secretbox(part, nonce, key);
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chunks.push(box);
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increment(nonce);
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}
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// TODO do something with the chunks...
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};
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return {
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decrypt: decrypt,
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encrypt: encrypt,
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};
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});
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