list argument must be an Array of Buffers

[peacemakr]

Version:
6.0.7

Environment:

• Operating system:
  Mac OSX
• Browser:
  Chrome
• Node.js:
  5.12.0
  Expected result:
  server should not crash
  Actual result:
  server is crashing with the following message

TypeError: list argument must be an Array of Buffers
    at Function.Buffer.concat (buffer.js:330:13)
    at IncomingMessage.onData (/test5/node_modules/engine.io/lib/transports/polling.js:161:23)
    at emitOne (events.js:90:13)
    at IncomingMessage.emit (events.js:182:7)
    at IncomingMessage.Readable.read (_stream_readable.js:368:10)
    at flow (_stream_readable.js:751:26)
    at resume_ (_stream_readable.js:731:3)
    at _combinedTickCallback (internal/process/next_tick.js:74:11)
    at process._tickDomainCallback (internal/process/next_tick.js:122:9)

Steps to reproduce:
Not sure what kind of input is causing that to happen... however this appears to be related to Engine.io not validating inputs etc

[lpinca]

I guess either chunks or data is not a buffer in this array.

Sounds like an external issue though.

[peacemakr]

it works normally in most cases, in fact it only occurred once to me

in any case, the code should be protected

[lpinca]

I vaguely remember a similar issue socketio/engine.io#305.

[lpinca]

This should have been fixed in engine.io@3.1.1. Please reopen if it's not the case.