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Throw if no cryptographic quality RNG available. Fixes #173.
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@broofa
broofa committed Oct 1, 2017
1 parent 0ea33e6 commit a05a7b4
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Showing 4 changed files with 98 additions and 65 deletions.
45 changes: 24 additions & 21 deletions lib/rng-browser.js
View file
Expand Up @@ -2,28 +2,31 @@
// browser this is a little complicated due to unknown quality of Math.random()
// and inconsistent support for the `crypto` API. We do the best we can via
// feature-detection
var getRandomValues = typeof(crypto) != 'undefined' && crypto.getRandomValues;
var rnds8 = new Uint8Array(16); // eslint-disable-line no-undef
var rnds = new Array(16);
var rng;

if (typeof(crypto) != 'undefined' && crypto.getRandomValues) {
// WHATWG crypto RNG - http://wiki.whatwg.org/wiki/Crypto
var rnds8 = new Uint8Array(16); // eslint-disable-line no-undef

module.exports = function whatwgRNG() {
crypto.getRandomValues(rnds8);
return rnds8;
};
} else {
// Math.random()-based (RNG)
//
// If all else fails, use Math.random(). It's fast, but is of unspecified
// quality.
var rnds = new Array(16);
function whatwgRNG() {
getRandomValues(rnds8);
return rnds8;
}

module.exports = function mathRNG() {
for (var i = 0, r; i < 16; i++) {
if ((i & 0x03) === 0) r = Math.random() * 0x100000000;
rnds[i] = r >>> ((i & 0x03) << 3) & 0xff;
}
function mathRNG() {
if (!rng._dubious) throw new Error('No good RNG available. See https://goo.gl/vz3J87');
for (var i = 0, r; i < 16; i++) {
if (i % 4 === 0) r = Math.random() * 0x100000000 | 0;
rnds[i] = r & 0xff;
r >>>= 8;
}

return rnds;
};
return rnds;
}


module.exports = rng = getRandomValues ? whatwgRNG : mathRNG;

// Hook for allowing the use of Math.random() as an RNG source
rng.allowDubiousRNG = function(flag) {
rng._dubious = flag;
};
10 changes: 7 additions & 3 deletions lib/rng.js
View file
Expand Up @@ -2,7 +2,11 @@
// this is pretty straight-forward - we use the crypto API.

var crypto = require('crypto');

module.exports = function nodeRNG() {
var rng = function nodeRNG() {
return crypto.randomBytes(16);
};
}

// Shim to keep API consistent across rng and rng-browser
rng.allowDubiousRNG = function() {};

module.exports = rng;
100 changes: 63 additions & 37 deletions test/test.js
View file
@@ -1,6 +1,10 @@
var assert = require('assert');

var uuid = require('../');
var uuidv1 = require('../v1');
var uuidv3 = require('../v3');
var uuidv4 = require('../v4');
var uuidv5 = require('../v5');
var crypto = require('crypto');

// Verify ordering of v1 ids created with explicit times
var TIME = 1321644961388; // 2011-11-18 11:36:01.388-08:00
Expand Down Expand Up @@ -49,6 +53,7 @@ function compare(name, ids) {
test('nodeRNG', function() {
var rng = require('../lib/rng');
assert.equal(rng.name, 'nodeRNG');
assert(rng.allowDubiousRNG, 'Supports dubious RNG API');

var bytes = rng();
assert.equal(bytes.length, 16);
Expand All @@ -61,6 +66,10 @@ test('nodeRNG', function() {
test('mathRNG', function() {
var rng = require('../lib/rng-browser');
assert.equal(rng.name, 'mathRNG');
assert(rng.allowDubiousRNG, 'Supports dubious RNG API');
assert.throws(rng);
rng.allowDubiousRNG(true);
assert.doesNotThrow(rng);

var bytes = rng();
assert.equal(bytes.length, 16);
Expand All @@ -71,6 +80,13 @@ test('mathRNG', function() {
});

test('cryptoRNG', function() {
var randomFillSync = crypto.randomFillSync;

// Purge require cache
Object.keys(require.cache).forEach(function(path) {
if (/rng-browser/.test(path)) delete require.cache[path];
});

// We shim the web crypto API to trigger cryptoRNG code path in rng module,
// then unshim once we've required it
global.crypto = {
Expand All @@ -81,6 +97,9 @@ test('cryptoRNG', function() {
var rng = require('../lib/rng-browser');
delete global.crypto;

assert(rng.allowDubiousRNG, 'Supports dubious RNG API');
assert.equal(rng.name, 'whatwgRNG');

var bytes = rng();
assert.equal(bytes.length, 16);

Expand Down Expand Up @@ -124,73 +143,73 @@ test('md5 browser', function() {
});

test('v3', function() {
var v3 = require('../v3');

// Expect to get the same results as http://tools.adjet.org/uuid-v3
assert.equal(v3('hello.example.com', v3.DNS), '9125a8dc-52ee-365b-a5aa-81b0b3681cf6');
assert.equal(v3('http://example.com/hello', v3.URL), 'c6235813-3ba4-3801-ae84-e0a6ebb7d138');
assert.equal(v3('hello', '0f5abcd1-c194-47f3-905b-2df7263a084b'), 'a981a0c2-68b1-35dc-bcfc-296e52ab01ec');
assert.equal(uuidv3('hello.example.com', uuidv3.DNS), '9125a8dc-52ee-365b-a5aa-81b0b3681cf6');
assert.equal(uuidv3('http://example.com/hello', uuidv3.URL), 'c6235813-3ba4-3801-ae84-e0a6ebb7d138');
assert.equal(uuidv3('hello', '0f5abcd1-c194-47f3-905b-2df7263a084b'), 'a981a0c2-68b1-35dc-bcfc-296e52ab01ec');

// test the buffer functionality
var buf = new Array(16);
var testBuf = [0x91, 0x25, 0xa8, 0xdc, 0x52, 0xee, 0x36, 0x5b, 0xa5, 0xaa, 0x81, 0xb0, 0xb3, 0x68, 0x1c, 0xf6];
v3('hello.example.com', v3.DNS, buf);
assert.ok(buf.length === testBuf.length && buf.every(function (elem, idx) { return elem === testBuf[idx]; }));
uuidv3('hello.example.com', uuidv3.DNS, buf);
assert.ok(buf.length === testBuf.length && buf.every(function(elem, idx) {
return elem === testBuf[idx];
}));

// test offsets as well
buf = new Array(19);
for (var i=0; i<3; ++i) buf[i] = 'landmaster';
v3('hello.example.com', v3.DNS, buf, 3);
uuidv3('hello.example.com', uuidv3.DNS, buf, 3);
assert.ok(buf.length === testBuf.length+3 && buf.every(function (elem, idx) {
return (idx >= 3) ? (elem === testBuf[idx-3]) : (elem === 'landmaster');
}), "hello");
});

test('v5', function() {
var v5 = require('../v5');

// Expect to get the same results as http://tools.adjet.org/uuid-v5
assert.equal(v5('hello.example.com', v5.DNS), 'fdda765f-fc57-5604-a269-52a7df8164ec');
assert.equal(v5('http://example.com/hello', v5.URL), '3bbcee75-cecc-5b56-8031-b6641c1ed1f1');
assert.equal(v5('hello', '0f5abcd1-c194-47f3-905b-2df7263a084b'), '90123e1c-7512-523e-bb28-76fab9f2f73d');
assert.equal(uuidv5('hello.example.com', uuidv5.DNS), 'fdda765f-fc57-5604-a269-52a7df8164ec');
assert.equal(uuidv5('http://example.com/hello', uuidv5.URL), '3bbcee75-cecc-5b56-8031-b6641c1ed1f1');
assert.equal(uuidv5('hello', '0f5abcd1-c194-47f3-905b-2df7263a084b'), '90123e1c-7512-523e-bb28-76fab9f2f73d');

// test the buffer functionality
var buf = new Array(16);
var testBuf = [0xfd, 0xda, 0x76, 0x5f, 0xfc, 0x57, 0x56, 0x04, 0xa2, 0x69, 0x52, 0xa7, 0xdf, 0x81, 0x64, 0xec];
v5('hello.example.com', v5.DNS, buf);
assert.ok(buf.length === testBuf.length && buf.every(function (elem, idx) { return elem === testBuf[idx]; }));
uuidv5('hello.example.com', uuidv5.DNS, buf);
assert.ok(buf.length === testBuf.length && buf.every(function(elem, idx) {
return elem === testBuf[idx];
}));

// test offsets as well
buf = new Array(19);
for (var i=0; i<3; ++i) buf[i] = 'landmaster';
v5('hello.example.com', v5.DNS, buf, 3);
assert.ok(buf.length === testBuf.length+3 && buf.every(function (elem, idx) {
uuidv5('hello.example.com', uuidv5.DNS, buf, 3);
assert.ok(buf.length === testBuf.length+3 && buf.every(function(elem, idx) {
return (idx >= 3) ? (elem === testBuf[idx-3]) : (elem === 'landmaster');
}));
});


// Verify ordering of v1 ids created using default behavior
compare('uuids with current time', [
uuid.v1(),
uuid.v1(),
uuid.v1(),
uuid.v1(),
uuid.v1()
uuidv1(),
uuidv1(),
uuidv1(),
uuidv1(),
uuidv1()
]);

// Verify ordering of v1 ids created with explicit times
compare('uuids with time option', [
uuid.v1({msecs: TIME - 10*3600*1000}),
uuid.v1({msecs: TIME - 1}),
uuid.v1({msecs: TIME}),
uuid.v1({msecs: TIME + 1}),
uuid.v1({msecs: TIME + 28*24*3600*1000})
uuidv1({msecs: TIME - 10*3600*1000}),
uuidv1({msecs: TIME - 1}),
uuidv1({msecs: TIME}),
uuidv1({msecs: TIME + 1}),
uuidv1({msecs: TIME + 28*24*3600*1000})
]);

test('msec', function() {
assert(
uuid.v1({msecs: TIME}) != uuid.v1({msecs: TIME}),
uuidv1({msecs: TIME}) !== uuidv1({msecs: TIME}),
'IDs created at same msec are different'
);
});
Expand All @@ -199,7 +218,7 @@ test('exception thrown when > 10k ids created in 1ms', function() {
// Verify throw if too many ids created
var thrown = false;
try {
uuid.v1({msecs: TIME, nsecs: 10000});
uuidv1({msecs: TIME, nsecs: 10000});
} catch (e) {
thrown = true;
}
Expand All @@ -208,8 +227,8 @@ test('exception thrown when > 10k ids created in 1ms', function() {

test('clock regression by msec', function() {
// Verify clock regression bumps clockseq
var uidt = uuid.v1({msecs: TIME});
var uidtb = uuid.v1({msecs: TIME - 1});
var uidt = uuidv1({msecs: TIME});
var uidtb = uuidv1({msecs: TIME - 1});
assert(
parseInt(uidtb.split('-')[3], 16) - parseInt(uidt.split('-')[3], 16) === 1,
'Clock regression by msec increments the clockseq'
Expand All @@ -218,8 +237,8 @@ test('clock regression by msec', function() {

test('clock regression by nsec', function() {
// Verify clock regression bumps clockseq
var uidtn = uuid.v1({msecs: TIME, nsecs: 10});
var uidtnb = uuid.v1({msecs: TIME, nsecs: 9});
var uidtn = uuidv1({msecs: TIME, nsecs: 10});
var uidtnb = uuidv1({msecs: TIME, nsecs: 9});
assert(
parseInt(uidtnb.split('-')[3], 16) - parseInt(uidtn.split('-')[3], 16) === 1,
'Clock regression by nsec increments the clockseq'
Expand All @@ -228,7 +247,7 @@ test('clock regression by nsec', function() {

test('explicit options product expected id', function() {
// Verify explicit options produce expected id
var id = uuid.v1({
var id = uuidv1({
msecs: 1321651533573,
nsecs: 5432,
clockseq: 0x385c,
Expand All @@ -239,10 +258,17 @@ test('explicit options product expected id', function() {

test('ids spanning 1ms boundary are 100ns apart', function() {
// Verify adjacent ids across a msec boundary are 1 time unit apart
var u0 = uuid.v1({msecs: TIME, nsecs: 9999});
var u1 = uuid.v1({msecs: TIME + 1, nsecs: 0});
var u0 = uuidv1({msecs: TIME, nsecs: 9999});
var u1 = uuidv1({msecs: TIME + 1, nsecs: 0});

var before = u0.split('-')[0], after = u1.split('-')[0];
var dt = parseInt(after, 16) - parseInt(before, 16);
assert(dt === 1, 'Ids spanning 1ms boundary are 100ns apart');
});

test('legacy API', function() {
var uuid = require('..');
assert.equal(uuid.v1, uuidv1, 'uuid.v1 = uuid/v1');
assert.equal(uuid.v4, uuidv4, 'uuid.v4 = uuid/v4');
assert.equal(uuid, uuidv4, 'uuid = uuid/v4');
});
8 changes: 4 additions & 4 deletions v1.js
View file
Expand Up @@ -24,17 +24,17 @@ function v1(options, buf, offset) {
// specified. We do this lazily to minimize issues related to insufficient
// system entropy. See #189
if (node == null || clockseq == null) {
var seedBytes = rng();
var rnds = options.random || (options.rng || rng)();
if (node == null) {
// Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
node = _nodeId = [
seedBytes[0] | 0x01,
seedBytes[1], seedBytes[2], seedBytes[3], seedBytes[4], seedBytes[5]
rnds[0] | 0x01,
rnds[1], rnds[2], rnds[3], rnds[4], rnds[5]
];
}
if (clockseq == null) {
// Per 4.2.2, randomize (14 bit) clockseq
clockseq = _clockseq = (seedBytes[6] << 8 | seedBytes[7]) & 0x3fff;
clockseq = _clockseq = (rnds[6] << 8 | rnds[7]) & 0x3fff;
}
}

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