Infinite loop under certain timing conditions with SSL connections

[JavierJF]

• A clear description of the issue

If certain timing conditions are met, ProxySQL keeps polling an already closed socket. For this event to happen, the socket for the connection should be already closed when 'SSL_INIT' connection state is taking place at ProxySQL side.

• ProxySQL version

v2.0.16
v2.1.1

• OS version

NAME="Arch Linux"
PRETTY_NAME="Arch Linux"
ID=arch
BUILD_ID=rolling

• The steps to reproduce the issue

1. Start ProxySQL under gdb.
2. Place a breakpoint at MySQL_Data_Stream::read_from_net.
3. Connect a MySQL client with --ssl-mode=REQUIRED to either ProxySQL Admin or regular client port.
4. First time 'SSL_INIT' is taking place when hitting the breakpoint, kill the client application.
5. Disable breakpoints and continue execution.
6. Infinite loop should be taking place.

[renecannao]

Fixed