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crypto: add randomInt function
PR-URL: #34600 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Tobias Nießen <[email protected]>
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‎doc/api/crypto.md‎

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@@ -2793,6 +2793,44 @@ threadpool request. To minimize threadpool task length variation, partition
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large `randomFill` requests when doing so as part of fulfilling a client
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request.
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2796+
### `crypto.randomInt([min, ]max[, callback])`
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<!-- YAML
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added: REPLACEME
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-->
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*`min`{integer} Start of random range (inclusive). **Default**: `0`.
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*`max`{integer} End of random range (exclusive).
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*`callback`{Function} `function(err, n){}`.
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Return a random integer `n` such that `min <= n < max`. This
2806+
implementation avoids [modulo bias][].
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The range (`max - min`) must be less than `2^48`. `min` and `max` must
2809+
be safe integers.
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If the `callback` function is not provided, the random integer is
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generated synchronously.
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```js
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// Asynchronous
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crypto.randomInt(3, (err, n) =>{
2817+
if (err) throw err;
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console.log(`Random number chosen from (0, 1, 2): ${n}`);
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});
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```
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```js
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// Synchronous
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constn=crypto.randomInt(3);
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console.log(`Random number chosen from (0, 1, 2): ${n}`);
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```
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```js
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// With `min` argument
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constn=crypto.randomInt(1, 7);
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console.log(`The dice rolled: ${n}`);
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```
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27962834
### `crypto.scrypt(password, salt, keylen[, options], callback)`
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<!-- YAML
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added: v10.5.0
@@ -3565,6 +3603,7 @@ See the [list of SSL OP Flags][] for details.
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[NIST SP 800-131A]: https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar1.pdf
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[NIST SP 800-132]: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-132.pdf
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[NIST SP 800-38D]: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
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[modulo bias]: https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle#Modulo_bias
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[Nonce-Disrespecting Adversaries]: https://github.com/nonce-disrespect/nonce-disrespect
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[OpenSSL's SPKAC implementation]: https://www.openssl.org/docs/man1.1.0/apps/openssl-spkac.html
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[RFC 1421]: https://www.rfc-editor.org/rfc/rfc1421.txt

‎lib/crypto.js‎

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Original file line numberDiff line numberDiff line change
@@ -52,7 +52,8 @@ const{
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const{
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randomBytes,
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randomFill,
55-
randomFillSync
55+
randomFillSync,
56+
randomInt
5657
}=require('internal/crypto/random');
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const{
5859
pbkdf2,
@@ -184,6 +185,7 @@ module.exports ={
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randomBytes,
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randomFill,
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randomFillSync,
188+
randomInt,
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scrypt,
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scryptSync,
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sign: signOneShot,

‎lib/internal/crypto/random.js‎

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@@ -3,6 +3,7 @@
33
const{
44
MathMin,
55
NumberIsNaN,
6+
NumberIsSafeInteger
67
}=primordials;
78

89
const{ AsyncWrap, Providers }=internalBinding('async_wrap');
@@ -119,6 +120,82 @@ function randomFill(buf, offset, size, cb){
119120
_randomBytes(buf,offset,size,wrap);
120121
}
121122

123+
// Largest integer we can read from a buffer.
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// e.g.: Buffer.from("ff".repeat(6), "hex").readUIntBE(0, 6);
125+
constRAND_MAX=0xFFFF_FFFF_FFFF;
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// Generates an integer in [min, max) range where min is inclusive and max is
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// exclusive.
129+
functionrandomInt(min,max,cb){
130+
// Detect optional min syntax
131+
// randomInt(max)
132+
// randomInt(max, cb)
133+
constminNotSpecified=typeofmax==='undefined'||
134+
typeofmax==='function';
135+
136+
if(minNotSpecified){
137+
cb=max;
138+
max=min;
139+
min=0;
140+
}
141+
142+
constisSync=typeofcb==='undefined';
143+
if(!isSync&&typeofcb!=='function'){
144+
thrownewERR_INVALID_CALLBACK(cb);
145+
}
146+
if(!NumberIsSafeInteger(min)){
147+
thrownewERR_INVALID_ARG_TYPE('min','safe integer',min);
148+
}
149+
if(!NumberIsSafeInteger(max)){
150+
thrownewERR_INVALID_ARG_TYPE('max','safe integer',max);
151+
}
152+
if(!(max>=min)){
153+
thrownewERR_OUT_OF_RANGE('max',`>= ${min}`,max);
154+
}
155+
156+
// First we generate a random int between [0..range)
157+
constrange=max-min;
158+
159+
if(!(range<=RAND_MAX)){
160+
thrownewERR_OUT_OF_RANGE(`max${minNotSpecified ? '' : ' - min'}`,
161+
`<= ${RAND_MAX}`,range);
162+
}
163+
164+
constexcess=RAND_MAX%range;
165+
constrandLimit=RAND_MAX-excess;
166+
167+
if(isSync){
168+
// Sync API
169+
while(true){
170+
constx=randomBytes(6).readUIntBE(0,6);
171+
// If x > (maxVal - (maxVal % range)), we will get "modulo bias"
172+
if(x>randLimit){
173+
// Try again
174+
continue;
175+
}
176+
constn=(x%range)+min;
177+
returnn;
178+
}
179+
}else{
180+
// Async API
181+
constpickAttempt=()=>{
182+
randomBytes(6,(err,bytes)=>{
183+
if(err)returncb(err);
184+
constx=bytes.readUIntBE(0,6);
185+
// If x > (maxVal - (maxVal % range)), we will get "modulo bias"
186+
if(x>randLimit){
187+
// Try again
188+
returnpickAttempt();
189+
}
190+
constn=(x%range)+min;
191+
cb(null,n);
192+
});
193+
};
194+
195+
pickAttempt();
196+
}
197+
}
198+
122199
functionhandleError(ex,buf){
123200
if(ex)throwex;
124201
returnbuf;
@@ -127,5 +204,6 @@ function handleError(ex, buf){
127204
module.exports={
128205
randomBytes,
129206
randomFill,
130-
randomFillSync
207+
randomFillSync,
208+
randomInt
131209
};

‎test/parallel/test-crypto-random.js‎

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@@ -315,3 +315,183 @@ assert.throws(
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assert.strictEqual(desc.writable,true);
316316
assert.strictEqual(desc.enumerable,false);
317317
});
318+
319+
320+
{
321+
// Asynchronous API
322+
constrandomInts=[];
323+
for(leti=0;i<100;i++){
324+
crypto.randomInt(3,common.mustCall((err,n)=>{
325+
assert.ifError(err);
326+
assert.ok(n>=0);
327+
assert.ok(n<3);
328+
randomInts.push(n);
329+
if(randomInts.length===100){
330+
assert.ok(!randomInts.includes(-1));
331+
assert.ok(randomInts.includes(0));
332+
assert.ok(randomInts.includes(1));
333+
assert.ok(randomInts.includes(2));
334+
assert.ok(!randomInts.includes(3));
335+
}
336+
}));
337+
}
338+
}
339+
{
340+
// Synchronous API
341+
constrandomInts=[];
342+
for(leti=0;i<100;i++){
343+
constn=crypto.randomInt(3);
344+
assert.ok(n>=0);
345+
assert.ok(n<3);
346+
randomInts.push(n);
347+
}
348+
349+
assert.ok(!randomInts.includes(-1));
350+
assert.ok(randomInts.includes(0));
351+
assert.ok(randomInts.includes(1));
352+
assert.ok(randomInts.includes(2));
353+
assert.ok(!randomInts.includes(3));
354+
}
355+
{
356+
// Positive range
357+
constrandomInts=[];
358+
for(leti=0;i<100;i++){
359+
crypto.randomInt(1,3,common.mustCall((err,n)=>{
360+
assert.ifError(err);
361+
assert.ok(n>=1);
362+
assert.ok(n<3);
363+
randomInts.push(n);
364+
if(randomInts.length===100){
365+
assert.ok(!randomInts.includes(0));
366+
assert.ok(randomInts.includes(1));
367+
assert.ok(randomInts.includes(2));
368+
assert.ok(!randomInts.includes(3));
369+
}
370+
}));
371+
}
372+
}
373+
{
374+
// Negative range
375+
constrandomInts=[];
376+
for(leti=0;i<100;i++){
377+
crypto.randomInt(-10,-8,common.mustCall((err,n)=>{
378+
assert.ifError(err);
379+
assert.ok(n>=-10);
380+
assert.ok(n<-8);
381+
randomInts.push(n);
382+
if(randomInts.length===100){
383+
assert.ok(!randomInts.includes(-11));
384+
assert.ok(randomInts.includes(-10));
385+
assert.ok(randomInts.includes(-9));
386+
assert.ok(!randomInts.includes(-8));
387+
}
388+
}));
389+
}
390+
}
391+
{
392+
393+
['10',true,NaN,null,{},[]].forEach((i)=>{
394+
constinvalidMinError={
395+
code: 'ERR_INVALID_ARG_TYPE',
396+
name: 'TypeError',
397+
message: 'The "min" argument must be safe integer.'+
398+
`${common.invalidArgTypeHelper(i)}`,
399+
};
400+
constinvalidMaxError={
401+
code: 'ERR_INVALID_ARG_TYPE',
402+
name: 'TypeError',
403+
message: 'The "max" argument must be safe integer.'+
404+
`${common.invalidArgTypeHelper(i)}`,
405+
};
406+
407+
assert.throws(
408+
()=>crypto.randomInt(i,100),
409+
invalidMinError
410+
);
411+
assert.throws(
412+
()=>crypto.randomInt(i,100,common.mustNotCall()),
413+
invalidMinError
414+
);
415+
assert.throws(
416+
()=>crypto.randomInt(i),
417+
invalidMaxError
418+
);
419+
assert.throws(
420+
()=>crypto.randomInt(i,common.mustNotCall()),
421+
invalidMaxError
422+
);
423+
assert.throws(
424+
()=>crypto.randomInt(0,i,common.mustNotCall()),
425+
invalidMaxError
426+
);
427+
assert.throws(
428+
()=>crypto.randomInt(0,i),
429+
invalidMaxError
430+
);
431+
});
432+
433+
constmaxInt=Number.MAX_SAFE_INTEGER;
434+
constminInt=Number.MIN_SAFE_INTEGER;
435+
436+
crypto.randomInt(minInt,minInt+5,common.mustCall());
437+
crypto.randomInt(maxInt-5,maxInt,common.mustCall());
438+
439+
assert.throws(
440+
()=>crypto.randomInt(minInt-1,minInt+5,common.mustNotCall()),
441+
{
442+
code: 'ERR_INVALID_ARG_TYPE',
443+
name: 'TypeError',
444+
message: 'The "min" argument must be safe integer.'+
445+
`${common.invalidArgTypeHelper(minInt-1)}`,
446+
}
447+
);
448+
449+
assert.throws(
450+
()=>crypto.randomInt(maxInt+1,common.mustNotCall()),
451+
{
452+
code: 'ERR_INVALID_ARG_TYPE',
453+
name: 'TypeError',
454+
message: 'The "max" argument must be safe integer.'+
455+
`${common.invalidArgTypeHelper(maxInt+1)}`,
456+
}
457+
);
458+
459+
crypto.randomInt(0,common.mustCall());
460+
crypto.randomInt(0,0,common.mustCall());
461+
assert.throws(()=>crypto.randomInt(-1,common.mustNotCall()),{
462+
code: 'ERR_OUT_OF_RANGE',
463+
name: 'RangeError',
464+
message: 'The value of "max" is out of range. It must be >= 0. Received -1'
465+
});
466+
467+
constMAX_RANGE=0xFFFF_FFFF_FFFF;
468+
crypto.randomInt(MAX_RANGE,common.mustCall());
469+
crypto.randomInt(1,MAX_RANGE+1,common.mustCall());
470+
assert.throws(
471+
()=>crypto.randomInt(1,MAX_RANGE+2,common.mustNotCall()),
472+
{
473+
code: 'ERR_OUT_OF_RANGE',
474+
name: 'RangeError',
475+
message: 'The value of "max - min" is out of range. '+
476+
`It must be <= ${MAX_RANGE}. `+
477+
'Received 281_474_976_710_656'
478+
}
479+
);
480+
481+
assert.throws(()=>crypto.randomInt(MAX_RANGE+1,common.mustNotCall()),{
482+
code: 'ERR_OUT_OF_RANGE',
483+
name: 'RangeError',
484+
message: 'The value of "max" is out of range. '+
485+
`It must be <= ${MAX_RANGE}. `+
486+
'Received 281_474_976_710_656'
487+
});
488+
489+
[true,NaN,null,{},[],10].forEach((i)=>{
490+
constcbError={
491+
code: 'ERR_INVALID_CALLBACK',
492+
name: 'TypeError',
493+
message: `Callback must be a function. Received ${inspect(i)}`
494+
};
495+
assert.throws(()=>crypto.randomInt(0,1,i),cbError);
496+
});
497+
}

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