test-buffer-concat.js

// Copyright Joyent, Inc. and other Node contributors.
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//
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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'use strict';
const common = require('../common');
const assert = require('assert');

const zero = [];
const one = [ Buffer.from('asdf') ];
const long = [];
for (let i = 0; i < 10; i++) long.push(Buffer.from('asdf'));

const flatZero = Buffer.concat(zero);
const flatOne = Buffer.concat(one);
const flatLong = Buffer.concat(long);
const flatLongLen = Buffer.concat(long, 40);

assert.strictEqual(flatZero.length, 0);
assert.strictEqual(flatOne.toString(), 'asdf');

const check = 'asdf'.repeat(10);

// A special case where concat used to return the first item,
// if the length is one. This check is to make sure that we don't do that.
assert.notStrictEqual(flatOne, one[0]);
assert.strictEqual(flatLong.toString(), check);
assert.strictEqual(flatLongLen.toString(), check);

[undefined, null, Buffer.from('hello')].forEach((value) => {
  assert.throws(() => {
    Buffer.concat(value);
  }, {
    code: 'ERR_INVALID_ARG_TYPE',
    message: 'The "list" argument must be an instance of Array.' +
             `${common.invalidArgTypeHelper(value)}`
  });
});

[[42], ['hello', Buffer.from('world')]].forEach((value) => {
  assert.throws(() => {
    Buffer.concat(value);
  }, {
    code: 'ERR_INVALID_ARG_TYPE',
    message: 'The "list[0]" argument must be an instance of Buffer ' +
             `or Uint8Array.${common.invalidArgTypeHelper(value[0])}`
  });
});

assert.throws(() => {
  Buffer.concat([Buffer.from('hello'), 3]);
}, {
  code: 'ERR_INVALID_ARG_TYPE',
  message: 'The "list[1]" argument must be an instance of Buffer ' +
           'or Uint8Array. Received type number (3)'
});

assert.throws(() => {
  Buffer.concat([Buffer.from('hello')], 3.5);
}, {
  code: 'ERR_OUT_OF_RANGE',
  message: 'The value of "length" is out of range. It must be an integer. ' +
           'Received 3.5'
});

assert.throws(() => {
  Buffer.concat([Buffer.from('hello')], -2);
}, {
  code: 'ERR_OUT_OF_RANGE',
  message: 'The value of "length" is out of range. It must be >= 0 && <= 9007199254740991. ' +
           'Received -2'
});

// eslint-disable-next-line node-core/crypto-check
const random10 = common.hasCrypto ?
  require('crypto').randomBytes(10) :
  Buffer.alloc(10, 1);
const derived18 = Buffer.alloc(18);
for (let i = 0, j = 0; i < 18; i++) {
  if (i < 10)
    derived18[i] = random10[i];
  else
    derived18[i] = random10[j++];
}
const empty = Buffer.alloc(0);

assert.notDeepStrictEqual(random10, empty);
assert.notDeepStrictEqual(random10, Buffer.alloc(10));

assert.deepStrictEqual(Buffer.concat([], 100), empty);
assert.deepStrictEqual(Buffer.concat([random10], 0), empty);
assert.deepStrictEqual(Buffer.concat([random10], 10), random10);
assert.deepStrictEqual(Buffer.concat([random10, random10], 10), random10);
assert.deepStrictEqual(Buffer.concat([random10, random10], 18), derived18);
assert.deepStrictEqual(Buffer.concat([empty, random10]), random10);
assert.deepStrictEqual(Buffer.concat([random10, empty, empty]), random10);

// The tail should be zero-filled
assert.deepStrictEqual(Buffer.concat([empty], 100), Buffer.alloc(100));
assert.deepStrictEqual(Buffer.concat([empty], 4096), Buffer.alloc(4096));
assert.deepStrictEqual(
  Buffer.concat([random10], 40),
  Buffer.concat([random10, Buffer.alloc(30)]));

assert.deepStrictEqual(Buffer.concat([new Uint8Array([0x41, 0x42]),
                                      new Uint8Array([0x43, 0x44])]),
                       Buffer.from('ABCD'));

// Spoofed length getter should not cause uninitialized memory exposure
{
  const u8_1 = new Uint8Array([1, 2, 3, 4]);
  const u8_2 = new Uint8Array([5, 6, 7, 8]);
  Object.defineProperty(u8_1, 'length', { get() { return 100; } });
  const buf = Buffer.concat([u8_1, u8_2]);
  assert.strictEqual(buf.length, 8);
  assert.deepStrictEqual(buf, Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]));
}