When using Openssl as TLS backend, close notify alert is not sent before closing the connection

[pjsipbot]

2019-08-28 13:01:05: @trengginas created the issue on trac ticket 2221

Before closing a connection, close notify alert must be sent to avoid truncation attack as stated in rfc5246:

7.2.1.  Closure Alerts

   The client and the server must share knowledge that the connection is
   ending in order to avoid a truncation attack.  Either party may
   initiate the exchange of closing messages.

Currently, the close notify alert is not sent before the connection is closed.

Thanks to Peter Koletzki for the report.

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2019-08-28 13:02:55: @trengginas changed status from new to closed

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2019-08-28 13:02:55: @trengginas set owner to @trengginas

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2019-08-28 13:02:55: @trengginas set resolution to fixed

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2019-08-28 13:02:55: @trengginas commented

In r6054:
Fixed #2221: When using Openssl as TLS backend, close notify alert is not sent before closing the connection.