90 lines
3.4 KiB
JavaScript
90 lines
3.4 KiB
JavaScript
import { PNG } from 'pngjs'
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import fs from 'fs'
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import { createHash, createPrivateKey, createSign } from 'crypto'
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import { server } from './index.js'
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export const ImageSecurity = {
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createImageHash: async (stream, isCape) => {
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const png = await new Promise((resolve, reject) => {
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stream.pipe(new PNG()).on('metadata', function(metadata) {
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if(metadata.width * metadata.height > 40960) {
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reject('Image size exceeds 40960 pixels')
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}
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}).on('parsed', function(_) {
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resolve(this)
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})
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})
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if (isCape) {
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if(png.width % 64 === 0 && png.height % 32 === 0) {
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return [createHashInternal(png), stream]
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} else if (png.width % 22 === 0 && png.height % 17 === 0) {
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const newPNG = new PNG({
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width: Math.ceil(png.width / 22),
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height: Math.ceil(png.height / 17),
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})
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for (let y = 0; y < png.height; y++) {
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for (let x = 0; x < png.width; x++) {
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const idx = (png.width * y + x) << 2
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newPNG.data[idx] = png.data[idx]
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newPNG.data[idx + 1] = png.data[idx + 1]
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newPNG.data[idx + 2] = png.data[idx + 2]
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newPNG.data[idx + 3] = png.data[idx + 3]
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}
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}
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for (let y = png.height; y < newPNG.height; y++) {
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for (let x = png.width; x < newPNG.width; x++) {
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const idx = (png.width * y + x) << 2
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newPNG.data[idx] = 0
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newPNG.data[idx + 1] = 0
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newPNG.data[idx + 2] = 0
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newPNG.data[idx + 3] = 0
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}
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}
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return [createHashInternal(newPNG), newPNG.pack()]
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}
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} else {
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if(png.width % 64 === 0 && png.height % 32 === 0) {
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const newPNG = new PNG({
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width: png.width,
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height: png.height
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})
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for (let y = 0; y < png.height; y++) {
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for (let x = 0; x < png.width; x++) {
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const idx = (png.width * y + x) << 2
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newPNG.data[idx] = png.data[idx]
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newPNG.data[idx + 1] = png.data[idx + 1]
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newPNG.data[idx + 2] = png.data[idx + 2]
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newPNG.data[idx + 3] = png.data[idx + 3]
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}
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}
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return [createHashInternal(png), newPNG.pack()]
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}
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}
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throw new Error('Invalid image size')
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},
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sign: (data) => {
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return createSign('RSA-SHA1').update(data).sign({ key: createPrivateKey(server.keys.privateKey) }, 'hex')
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}
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}
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const createHashInternal = (png) => {
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const hash = createHash('sha256')
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for (let y = 0; y < png.height; y++) {
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for (let x = 0; x < png.width; x++) {
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const idx = (png.width * y + x) << 2
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hash.update(png.data[idx].toString(16))
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hash.update(png.data[idx + 1].toString(16))
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hash.update(png.data[idx + 2].toString(16))
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hash.update(png.data[idx + 3].toString(16))
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}
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}
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return hash.digest('hex')
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}
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