I have a socket server written in python accepting connections like:

            self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

            # set the socket as non-blocking
            self.socket.setblocking(False)

            # bind
            self.socket.bind((self.host, int(self.port)))

            # listen
            self.socket.listen()
            

in a separate async function, i’m calling:

    conn, address = await self.loop.sock_accept(self.socket)

Once the connections is made, it is passed to :

    loop.connect_accepted_socket(lambda: <custom asyncio.Protocol class>, ssl=ssl_context)

When the connection fails to establish, the error is caught under:

except ssl.SSLError as e:
   print(e)

Where e can be a range of ssl errors.

Some of them are:

1. [SSL: WRONG_VERSION_NUMBER]
2. [SSL: SSLV3_ALERT_BAD_CERTIFICATE] sslv3 alert bad certificate (_ssl.c:1091)

Under such scenarios, i’d like to be able to print out the certificate that we had received from the client.

Is there a way to do this?

I’ve tried printing conn.getpeercert() in the exception handler, however, i get the error message:

AttributeError: ‘socket’ object has no attribute ‘getpeercert’

Whereas, if the connection does succeed, i’m able to get the peer certs from the transport object by calling

transport.get_extra_info(“peercert”)

I’d like to know if there is a way to print the certificate received from the client upon failure to verify.