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Backport «buffer: ignore negative allocation lengths» to v5.x #7221

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Merged
ChALkeR merged 1 commit into from
Jun 17, 2016
Merged

Backport «buffer: ignore negative allocation lengths» to v5.x #7221

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4 changes: 2 additions & 2 deletions lib/buffer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -163,8 +163,8 @@ Object.setPrototypeOf(SlowBuffer, Uint8Array);


function allocate(size) {
if (size === 0) {
return createBuffer(size);
if (size <= 0) {
return createBuffer(0);
}
if (size < (Buffer.poolSize >>> 1)) {
if (size > (poolSize - poolOffset))
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11 changes: 11 additions & 0 deletions test/parallel/test-buffer.js
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Expand Up @@ -1438,3 +1438,14 @@ assert.equal(Buffer.prototype.parent, undefined);
assert.equal(Buffer.prototype.offset, undefined);
assert.equal(SlowBuffer.prototype.parent, undefined);
assert.equal(SlowBuffer.prototype.offset, undefined);

{
// Test that large negative Buffer length inputs don't affect the pool offset.
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@trevnorris trevnorris Jun 13, 2016

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Just curious, why have we started blocking when no block-scope variables are being used?

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@addaleax addaleax Jun 13, 2016

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@trevnorris Someone suggested it to make sure that the last call in the block here wouldn’t be accidentally moved around in the file/away from the preceding calls that made it fail

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@ChALkeR ChALkeR Jun 13, 2016 •
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That was @Fishrock123 in #7051 (comment).

assert.deepStrictEqual(Buffer(-Buffer.poolSize), Buffer.from(''));
assert.deepStrictEqual(Buffer(-100), Buffer.from(''));
assert.deepStrictEqual(Buffer.allocUnsafe(-Buffer.poolSize), Buffer.from(''));
assert.deepStrictEqual(Buffer.allocUnsafe(-100), Buffer.from(''));

// Check pool offset after that by trying to write string into the pool.
assert.doesNotThrow(() => Buffer.from('abc'));
}