Int32 overflow when creating a buffer

[rgrannell1]

• Version: v7.9.0
• Platform: Linux ***** 4.4.0-72-generic [stream] support piping multiple streams into a single stream #93-Ubuntu SMP Fri Mar 31 14:07:41 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
• Subsystem: stream

I noticed that there's an unhandled overflow error in stream.Readable in work earlier today; when large values are supplied as highWaterMark the value used by the created object wraps around to a negative number. This didn't cause us massive problems, but it is a little difficult to debug (given that most people won't read the contents of _readableState)

console.log(
	require('stream').Readable({
		highWaterMark: 2147483647
	})._readableState.highWaterMark
)

console.log(
	require('stream').Readable({
		highWaterMark: 2147483647 + 1
	})._readableState.highWaterMark
)

which outputs:

2147483647
-2147483648

This should ideally throw an error, or support larger numeric values.

[cjihrig]

You may be running into these lines.

> ~~(2147483647)
2147483647
> ~~(2147483647 + 1)
-2147483648

[tniessen]

@cjihrig Was about to write the same thing, appears to be the problem.

[tniessen]

This should ideally throw an error, or support larger numeric values.

Thoughts on this? 2^31 is a fairly high value for highWaterMark. Is there any real-world use for bigger values?

[cjihrig]

I'd personally be in favor of some input validation, but I'd like to know what @nodejs/streams thinks.

[mcollina]

I'm definitely +1 for input validation. That large value is really a bug, because you are essentially disabling backpressure, and you are exposing yourself to out-of-memory errors.

[mcollina]

Fixed in #12593.