37df009806
May or may not break depending on the build of sjcl and/or minification options. It remains to be seen.
108 lines
5 KiB
TypeScript
108 lines
5 KiB
TypeScript
import { profanity } from "@2toad/profanity";
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// import { AES_CCM } from "@trafficlunar/asmcrypto.js";
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import sjcl from "sjcl-with-all";
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import { MII_DECRYPTION_KEY, MII_QR_ENCRYPTED_LENGTH } from "./constants";
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import Mii from "./mii.js/mii";
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import TomodachiLifeMii from "./tomodachi-life-mii";
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// AES-CCM encrypted Mii QR codes have some errata (https://www.3dbrew.org/wiki/AES_Registers#CCM_mode_pitfall)
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// causing them to not be easily decryptable by asmcrypto
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// or sjcl, they can't verify the nonce/tag.
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// In order to use sjcl's decrypt function without
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// verification, a private function needs to be called.
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// This private function's name is originally "_ctrMode"
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// but its name is minified across builds.
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// In "sjcl-with-all" v1.0.8 from npm, the name is "u"
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/** Private _ctrMode function defined here: {@link https://github.com/bitwiseshiftleft/sjcl/blob/85caa53c281eeeb502310013312c775d35fe0867/core/ccm.js#L194} */
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const sjclCcmCtrMode: ((
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prf: sjcl.SjclCipher, data: sjcl.BitArray, iv: sjcl.BitArray,
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tag: sjcl.BitArray, tlen: number, L: number
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) => { data: sjcl.BitArray; tag: sjcl.BitArray }) | undefined =
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// @ts-expect-error -- Referencing a private function that is not in the types.
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sjcl.mode.ccm.u; // NOTE: This may need to be changed with a different sjcl build. Read above
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export function convertQrCode(bytes: Uint8Array): { mii: Mii; tomodachiLifeMii: TomodachiLifeMii } {
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// Decrypt 96 byte 3DS/Wii U format Mii data from the QR code.
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// References (Credits: jaames, kazuki-4ys):
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// - https://gist.github.com/jaames/96ce8daa11b61b758b6b0227b55f9f78
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// - https://github.com/kazuki-4ys/kazuki-4ys.github.io/blob/148dc339974f8b7515bfdc1395ec1fc9becb68ab/web_apps/MiiInfoEditorCTR/encode.js#L57
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// Check that the private _ctrMode function is defined.
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if (!sjclCcmCtrMode) {
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throw new Error("Private sjcl.mode.ccm._ctrMode function cannot be found. The build of sjcl expected may have changed. Read src/lib/qr-codes.ts for more details.");
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}
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// Verify that the length is not smaller than expected.
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if (bytes.length < MII_QR_ENCRYPTED_LENGTH) {
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throw new Error(`Mii QR code has wrong size (got ${bytes.length}, expected ${MII_QR_ENCRYPTED_LENGTH} or longer)`);
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}
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const nonce = bytes.subarray(0, 8); // Extract the AES-CCM nonce.
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const encryptedContent = bytes.subarray(8); // Extract the ciphertext.
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const cipher = new sjcl.cipher.aes(MII_DECRYPTION_KEY); // Construct new sjcl cipher.
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// Convert encrypted content and nonce to sjcl.BitArray (toBits expects array)
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const encryptedBits = sjcl.codec.bytes.toBits(Array.from(encryptedContent));
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const nonceBits = sjcl.codec.bytes.toBits([...nonce, 0, 0, 0, 0]); // Pad to 12 bytes.
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// Isolate the actual ciphertext from the tag and adjust IV.
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// Copied from sjcl.mode.ccm.decrypt: https://github.com/bitwiseshiftleft/sjcl/blob/85caa53c281eeeb502310013312c775d35fe0867/core/ccm.js#L83
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const tlen = 128; // Tag length in bits.
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const dataWithoutTag = sjcl.bitArray.clamp(encryptedBits,
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// remove tag from out, tag length = 128
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sjcl.bitArray.bitLength(encryptedBits) - tlen);
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let decryptedBits: { data: sjcl.BitArray };
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try {
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decryptedBits = sjclCcmCtrMode(cipher, dataWithoutTag, nonceBits, [], tlen, 3); // hardcoding 3 as "L" / length
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} catch {
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// Note that the function above is not likely to fail since it decrypts without verification.
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throw new Error("Failed to decrypt QR code. It may be invalid or corrupted");
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}
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// NOTE: The CBC-MAC within the QR code is NOT verified here.
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// Convert the decrypted bytes from sjcl format.
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const decryptedBytes = sjcl.codec.bytes.fromBits(decryptedBits.data);
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const decryptedSlice = new Uint8Array(decryptedBytes).subarray(0, 88);
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// Create the final Mii StoreData from the decrypted bytes.
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const result = new Uint8Array([
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...decryptedSlice.subarray(0, 12), // First 12 decrypted bytes.
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...nonce, // Original nonce from the encrypted bytes.
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...decryptedSlice.subarray(12), // Then the rest of the decrypted bytes.
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]);
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// Check if Mii data is valid by checking always zero "reserved_2" field.
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if (result[0x16] !== 0 && result[0x17] !== 0) {
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throw new Error("QR code is not a valid Mii QR code");
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}
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// Construct mii-js Mii and TomodachiLifeMii classes.
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try {
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const buffer = Buffer.from(result); // Convert to node Buffer.
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const mii = new Mii(buffer); // Will verify the Mii data further.
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// Decrypt Tomodachi Life Mii data from encrypted QR code bytes.
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const tomodachiLifeMii = TomodachiLifeMii.fromBytes(bytes);
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// Apply hair dye fields.
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if (tomodachiLifeMii.hairDyeEnabled) {
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mii.hairColor = tomodachiLifeMii.studioHairColor;
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mii.eyebrowColor = tomodachiLifeMii.studioHairColor;
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mii.facialHairColor = tomodachiLifeMii.studioHairColor;
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}
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// Censor potential inappropriate words.
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tomodachiLifeMii.firstName = profanity.censor(tomodachiLifeMii.firstName);
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tomodachiLifeMii.lastName = profanity.censor(tomodachiLifeMii.lastName);
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tomodachiLifeMii.islandName = profanity.censor(tomodachiLifeMii.islandName);
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return { mii, tomodachiLifeMii };
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} catch (error) {
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console.error(error);
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throw new Error("Mii data is not valid");
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}
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}
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