Backported from main: b25738c416
When a packet contains binary elements, the built-in parser does not modify them and simply sends them in their own WebSocket frame.
Example: `socket.emit("some event", Buffer.of(1,2,3))`
is encoded and transferred as:
- 1st frame: 51-["some event",{"_placeholder":true,"num":0}]
- 2nd frame: <buffer 01 02 03>
where:
- `5` is the type of the packet (binary message)
- `1` is the number of binary attachments
- `-` is the separator
- `["some event",{"_placeholder":true,"num":0}]` is the payload (including the placeholder)
On the receiving end, the parser reads the number of attachments and buffers them until they are all received.
Before this change, the built-in parser accepted any number of binary attachments, which could be exploited to make the server run out of memory.
The number of attachments is now limited to 10, which should be sufficient for most use cases.
The limit can be increased with a custom `parser`:
```js
import { Encoder, Decoder } from "socket.io-parser";
const io = new Server({
parser: {
Encoder,
Decoder: class extends Decoder {
constructor() {
super({
maxAttachments: 20
});
}
}
}
});
```
A packet like '2[{"toString":"foo"}]' was decoded as:
{
type: EVENT,
data: [ { "toString": "foo" } ]
}
Which would then throw an error when passed to the EventEmitter class:
> TypeError: Cannot convert object to primitive value
> at Socket.emit (node:events:507:25)
> at .../node_modules/socket.io/lib/socket.js:531:14
History of the isPayloadValid() method:
- added in [78f9fc2](78f9fc2) (v4.0.1, socket.io@3.0.0)
- updated in [1c220dd](1c220dd) (v4.0.4, socket.io@3.1.0)
Backported from 3b78117bf6
A specially crafted packet could be incorrectly decoded.
Example:
```js
const decoder = new Decoder();
decoder.on("decoded", (packet) => {
console.log(packet.data); // prints [ 'hello', [Function: splice] ]
})
decoder.add('51-["hello",{"_placeholder":true,"num":"splice"}]');
decoder.add(Buffer.from("world"));
```
As usual, please remember not to trust user input.
Backported from b5d0cb7dc5
When maxHttpBufferSize is large (1e8 bytes), a payload of length 100MB
can be sent like so:
99999991:422222222222222222222222222222222222222222222...
This massive packet can cause OOM via building up many many
`ConsOneByteString` objects due to concatenation:
99999989 `ConsOneByteString`s and then converting the massive integer to
a `Number`.
The performance can be improved to avoid this by using `substring`
rather than building the string via concatenation.
Below I tried one payload of length 7e7 as the 1e8 payload took so
long to process that it timed out before running out of memory.
```
==== JS stack trace =========================================
0: ExitFrame [pc: 0x13c5b79]
Security context: 0x152fe7b808d1 <JSObject>
1: decodeString [0x2dd385fb5d1] [/node_modules/socket.io-parser/index.js:~276] [pc=0xf59746881be](this=0x175d34c42b69 <JSGlobal Object>,0x14eccff10fe1 <Very long string[69999990]>)
2: add [0x31fc2693da29] [/node_modules/socket.io-parser/index.js:242] [bytecode=0xa7ed6554889 offset=11](this=0x0a2881be5069 <Decoder map = 0x3ceaa8bf48c9>,0x14eccff10fe1 <Very...
FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
1: 0xa09830 node::Abort() [node]
2: 0xa09c55 node::OnFatalError(char const*, char const*) [node]
3: 0xb7d71e v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool) [node]
4: 0xb7da99 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [node]
5: 0xd2a1f5 [node]
6: 0xd2a886 v8::internal::Heap::RecomputeLimits(v8::internal::GarbageCollector) [node]
7: 0xd37105 v8::internal::Heap::PerformGarbageCollection(v8::internal::GarbageCollector, v8::GCCallbackFlags) [node]
8: 0xd37fb5 v8::internal::Heap::CollectGarbage(v8::internal::AllocationSpace, v8::internal::GarbageCollectionReason, v8::GCCallbackFlags) [node]
9: 0xd3965f v8::internal::Heap::HandleGCRequest() [node]
10: 0xce8395 v8::internal::StackGuard::HandleInterrupts() [node]
11: 0x1042cb6 v8::internal::Runtime_StackGuard(int, unsigned long*, v8::internal::Isolate*) [node]
12: 0x13c5b79 [node]
```
- bump debug to version 2.3.3
- bump component-emitter to version 1.2.1
- bump benchmark to version 2.1.2
- bump expect.js to version 0.3.1
- bump mocha to version 3.2.0
- bump zuul to version 3.11.1
