serverconnect - cert is alway None

Problem Description

I’ve configured an mitmProxy in upstream mode, and trying to intercept the certificate it (Fiddler) presents to mitmProxy using an add-on.

cert field frommitmproxy.connections.ServerConnection object is always None

Maybe I’m doing something wrong…

Steps to reproduce the behavior:

import mitmproxy
from mitmproxy import ctx


class MyAddon:

    def serverconnect(self, conn: mitmproxy.connections.ServerConnection):
        ctx.log.info("serverconnect: %s" % vars(conn))

addons = [
    MyAddon()
]

System Information

5.0.1

[Prinzhorn]

I’m trying to create a custom “trust manager” by inspecting cert.x509._subject_invalidator and if it’s created by a specific issuer, pass-trough the request, otherwise block it.

In this case you can work around by using the request event and flow.kill() if your check fails.

Pseudocode:

request(flow):
    if(flow.server_conn.cert......):
        flow.kill()

[mhils]

I think @Prinzhorn’s previous comment achieves just that. We will eventually expose the relevant OpenSSL bits in an addon, but for now @Prinzhorn’s approach is probably the best way to go next to monkeypatching the core.