const crypto = require('crypto');
const zlib = require('zlib');
const { promisify } = require('util');
-const { base64ToBase64URL, base64URLToBase64 } = require('@squeep/base64url');
const common = require('./common');
const allVersions = require('./version-parameters');
const { performance } = require('perf_hooks');
// Filter any unavailable algorithms
const availableCiphers = crypto.getCiphers();
+ const availableHashes = crypto.getHashes();
+ // Add legacy scrypt to available hashes for filtering key derivations
+ availableHashes.push(allVersions.KD.SCRYPT);
this.versionParameters = Object.entries(allVersions).reduce((acc, [v, p]) => {
- if (availableCiphers.includes(p.algorithm)) {
+ const validCipher = availableCiphers.includes(p.algorithm);
+ const validKeyDeriver = availableHashes.includes(p.keyDeriver);
+ if (validCipher && validKeyDeriver) {
acc[v] = p; // eslint-disable-line security/detect-object-injection
}
return acc;
}
+ /**
+ * Generate key data.
+ */
+ static async _keyFromSecret(deriver, secret, salt, keyBytes) {
+ switch (deriver) {
+ case allVersions.KD.SHAKE256: {
+ const hash = crypto.createHash(allVersions.KD.SHAKE256, { outputLength: keyBytes });
+ hash.update(salt);
+ hash.update(secret);
+ return hash.digest();
+ }
+
+ case allVersions.KD.BLAKE2B512: {
+ const hash = crypto.createHash(allVersions.KD.BLAKE2B512);
+ hash.update(salt);
+ hash.update(secret);
+ const digest = hash.digest();
+ // should assert that keyBytes <= 64
+ // but not concerned about that for now
+ // until we have a new algorithm with bigger key size
+ return digest.subarray(0, keyBytes);
+ }
+
+ case allVersions.KD.SCRYPT:
+ return scryptAsync(secret, salt, keyBytes);
+
+ default:
+ throw new RangeError('unsupported key deriver');
+ }
+ }
+
+
+ /**
+ * Return bits and bit mask for given number of encoded bytes.
+ * @param {Number} numBytes
+ * @returns {Object}
+ */
+ static _versionHeaderBits(numBytes) {
+ // Round up to 8 bits in result, just to be proper.
+ const resultBits = (((numBytes + 7) >> 3) << 3) >>> 0;
+ return {
+ headerValue: ((0xff << (resultBits - numBytes + 1)) & 0xff) >>> 0,
+ headerMask: ((0xff << (resultBits - numBytes)) & 0xff) >>> 0,
+ };
+ }
+
+
+ /**
+ * Parse a byte into the total number of bytes in the packed number,
+ * returning that and the new value for the first byte, to update in the
+ * buffer before parsing as an unsigned integer.
+ * Number of packed bytes is indicated by location of first leading 0 bit.
+ * Support for numbers larger than 127 is of dubious practicality, but here
+ * it is anyhow.
+ * @param {Number} firstByte
+ * @returns {Object}
+ */
+ static _versionHeaderDecode(firstByte) {
+ for (let numBytes = 1; numBytes <= 8; numBytes++) {
+ const {
+ headerValue,
+ headerMask,
+ } = MysteryBox._versionHeaderBits(numBytes);
+ if (((firstByte & headerMask) >>> 0) === headerValue) {
+ const restMask = (~headerMask & 0xff) >>> 0;
+ return {
+ numBytes,
+ firstByte: (firstByte & restMask) >>> 0,
+ };
+ }
+ }
+ // Nine bytes would be an extravagence.
+ throw new RangeError(`unsupported version header (0x${firstByte.toString(16)})`);
+ }
+
+
+ /**
+ * Decode leading bytes of buffer as version identifier.
+ * In the first byte, the position of the first unset bit indicates how
+ * many total bytes comprise the version, in big-endian encoding.
+ * Returns decoded version and number of bytes used to decode.
+ * Only supports up to 6-byte numbers, and of those, only up to 4398046511103.
+ * @param {Buffer} buf - N.B. will be mogrified
+ * @returns {Object}
+ */
+ static _versionDecode(buf) {
+ const headerByte = buf.readUInt8(0);
+ const { numBytes: versionBytes, firstByte } = MysteryBox._versionHeaderDecode(headerByte);
+ if (versionBytes === 1) {
+ return {
+ version: firstByte,
+ versionBytes,
+ };
+ }
+
+ if (versionBytes > 6) {
+ throw new RangeError(`unsupported version (${versionBytes} bytes)`);
+ }
+
+ // Otherwise, update the masked first byte and parse the rest of the buffer.
+ buf[0] = firstByte;
+ return {
+ version: buf.readUIntBE(0, versionBytes),
+ versionBytes,
+ };
+ }
+
+
+ /**
+ * Encode a version identifier into a buffer of a variable number of bytes.
+ * @param {Number} version
+ * @returns {Object}
+ */
+ static _versionEncode(version) {
+ let versionBytes = 0;
+
+ if (version <= 0x7f) { // 0-127
+ versionBytes = 1;
+ } else if (version <= 0x3fff) { // 128-16383
+ versionBytes = 2;
+ } else if (version <= 0x1fffff) { // 16384-2097151
+ versionBytes = 3;
+ } else if (version <= 0x0fffffff) { // 2097152-268435455
+ versionBytes = 4;
+ } else if (version <= 0x07ffffffff) { // 268435456-34359738367
+ versionBytes = 5;
+ } else if (version <= 0x03ffffffffff) { // 34359738368-4398046511103
+ versionBytes = 6;
+ } else {
+ throw new RangeError('version too large to encode');
+ }
+
+ const buffer = Buffer.alloc(versionBytes);
+ buffer.writeUIntBE(version, 0, versionBytes);
+ const headerByte = ((0xff << (8 - versionBytes + 1)) & 0xff) >>> 0;
+ buffer[0] = (buffer[0] | headerByte) >>> 0;
+
+ return {
+ buffer,
+ versionBytes,
+ };
+ }
+
+
/**
* Put contents into a mysterious box.
* @param {Object|Buffer} contents
+ * @param {Number=} version
+ * @param {Number=} flags
* @returns {String}
*/
async pack(contents, version = this.bestVersion, flags = this.defaultFlags) {
start: performance.now(),
preCompress: 0,
postCompress: 0,
- preEncrypt: 0,
- postEncrypt: 0,
+ preCrypt: 0,
+ postCrypt: 0,
end: 0,
};
+ const stats = {
+ version,
+ flags: undefined,
+ serializedBytes: undefined, // original contents size in bytes
+ compressedBytes: undefined, // compressed contents size in bytes
+ };
if (!(version in this.versionParameters)) {
throw new RangeError(`MysteryBox format version ${version} not supported`);
// eslint-disable-next-line security/detect-object-injection
const v = this.versionParameters[version];
- const { compression } = MysteryBox._decodeFlags(flags);
+ const { compression, payloadIsBuffer } = MysteryBox._decodeFlags(flags);
if (Buffer.isBuffer(contents)) {
+ // Ensure payloadIsBuffer flag is set when contents are indeed a Buffer
flags |= this.Flags.BufferPayload;
} else {
- contents = JSON.stringify(contents);
+ if (payloadIsBuffer) {
+ // Flag is set, but contents are not a Buffer? Try to coerce contents.
+ contents = Buffer.from(contents);
+ } else {
+ // Otherwise attempt to serialize the object
+ contents = JSON.stringify(contents);
+ }
}
+ stats.serializedBytes = Buffer.byteLength(contents);
- const versionBuffer = Buffer.alloc(v.versionBytes);
- versionBuffer.writeUInt8(v.version, 0);
+ const { buffer: versionBuffer, versionBytes } = MysteryBox._versionEncode(v.version);
+ if (versionBytes !== v.versionBytes) {
+ throw new Error('internal inconsistency, mismatched version byte length');
+ }
const [iv, salt] = await Promise.all([
v.ivBytes,
compressedContents = await deflateRawAsync(contents);
break;
}
+ stats.compressedBytes = Buffer.byteLength(compressedContents);
+ // const compressionRatio = stats.compressedBytes / stats.serializedBytes;
timingsMs.postCompress = timingsMs.preCrypt = performance.now();
let payload;
- if (compressedContents.length >= contents.length) {
+ if (stats.compressedBytes >= stats.serializedBytes) {
+ // If compression is not beneficial enough, or detrimental, do not use
flags = flags & ~compressionFlagsMask;
payload = contents;
+ stats.compressedBytes = undefined;
} else {
payload = compressedContents;
}
+
const flagsBuffer = Buffer.alloc(v.flagsBytes);
flagsBuffer.writeUInt8(flags, 0);
+ stats.flags = this._prettyFlags(flags);
// Authenticate all this data
const aadBuffer = Buffer.concat([versionBuffer, flagsBuffer, iv, salt]);
// Always encrypt with first secret
const secret = this.secrets[0];
- const key = await scryptAsync(secret, salt, v.keyBytes);
+ const key = await MysteryBox._keyFromSecret(v.keyDeriver, secret, salt, v.keyBytes);
const cipher = crypto.createCipheriv(v.algorithm, key, iv, v.algOptions);
cipher.setAAD(aadBuffer);
const encrypted = cipher.update(payload);
const final = cipher.final();
const tag = cipher.getAuthTag();
- const merged = Buffer.concat([versionBuffer, flagsBuffer, iv, salt, tag, encrypted, final]).toString('base64');
- const result = base64ToBase64URL(merged);
+ const result = Buffer.concat([versionBuffer, flagsBuffer, iv, salt, tag, encrypted, final]).toString('base64url');
timingsMs.end = timingsMs.postCrypt = performance.now();
- this.logger.debug(_scope, 'statistics', { version, flags: this._prettyFlags(flags), serialized: contents.length, compressed: payload.length, encoded: result.length, ...MysteryBox._timingsLog(timingsMs) });
+ this.logger.debug(_scope, 'statistics', { ...stats, ...MysteryBox._timingsLog(timingsMs) });
return result;
}
throw new RangeError('nothing to unpack');
}
- const raw = Buffer.from(base64URLToBase64(box), 'base64');
+ const raw = Buffer.from(box, 'base64url');
let offset = 0;
- const version = raw.subarray(offset, 1).readUInt8(0);
+ const { version, versionBytes } = MysteryBox._versionDecode(raw);
if (!(version in this.versionParameters)) {
throw new RangeError('unsupported version');
}
// eslint-disable-next-line security/detect-object-injection
const v = this.versionParameters[version];
+
+ if (v.versionBytes !== versionBytes) {
+ throw new Error('internal inconsistency, mismatched version byte length');
+ }
offset += v.versionBytes;
const minBytes = v.versionBytes + v.flagsBytes + v.ivBytes + v.saltBytes + v.tagBytes;
let err;
let success = false;
for await (const secret of this.secrets) {
- const key = await scryptAsync(secret, salt, v.keyBytes);
+ const key = await MysteryBox._keyFromSecret(v.keyDeriver, secret, salt, v.keyBytes);
const decipher = crypto.createDecipheriv(v.algorithm, key, iv, v.algOptions);
decipher.setAAD(aad);
decipher.setAuthTag(tag);
projects / squeep-mystery-box / blobdiff