Package Instance

Allocation of Resources Without Limits or Throttling
Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. The `SniHandler` can allocate up to 16MB of heap for each channel during the TLS handshake. When the handler or the channel does not have an idle timeout, it can be used to make a TCP server using the `SniHandler` to allocate 16MB of heap. The `SniHandler` class is a handler that waits for the TLS handshake to configure a `SslHandler` according to the indicated server name by the `ClientHello` record. For this matter it allocates a `ByteBuf` using the value defined in the `ClientHello` record. Normally the value of the packet should be smaller than the handshake packet but there are not checks done here and the way the code is written, it is possible to craft a packet that makes the `SslClientHelloHandler`. This vulnerability has been fixed in version 4.1.94.Final.

SslHandler doesn't correctly validate packets which can lead to native crash when using native SSLEngine
### Impact
When a special crafted packet is received via SslHandler it doesn't correctly handle validation of such a packet in all cases which can lead to a native crash.

### Workarounds
As workaround its possible to either disable the usage of the native SSLEngine or changing the code from:

```
SslContext context = ...;
SslHandler handler = context.newHandler(....);
```

to:

```
SslContext context = ...;
SSLEngine engine = context.newEngine(....);
SslHandler handler = new SslHandler(engine, ....);
```